Performance Characteristics of Compact Mobile LIFS (Laser-Induced Fluorescence Spectrum) Lidar

NASA Astrophysics Data System (ADS)

Tomida, Takayuki; Nishizawa, Naoto; Sakurai, Kosuke; Suganumata, Hikaru; Tsukada, Shodai; Song, Sung-Moo; Park, Ho-Dong; Saito, Yasunori

2016-06-01

We developed a compact but versatile laser-induced fluorescence spectrum (LIFS) lidar that has potential use for material or aerosol identification outside experimental rooms. The compactness and mobility of the LIFS lidar means observations can be more freely conducted at any place and any time. Its performance characteristics were validated by threedimensional fluorescence imaging of targets and remote detection of quasi bio/organic aerosols.

Compact lidar system using laser diode, binary continuous wave power modulation, and an avalanche photodiode-based receiver controlled by a digital signal processor

NASA Astrophysics Data System (ADS)

Ardanuy, Antoni; Comerón, Adolfo

2018-04-01

We analyze the practical limits of a lidar system based on the use of a laser diode, random binary continuous wave power modulation, and an avalanche photodiode (APD)-based photereceiver, combined with the control and computing power of the digital signal processors (DSP) currently available. The target is to design a compact portable lidar system made all in semiconductor technology, with a low-power demand and an easy configuration of the system, allowing change in some of its features through software. Unlike many prior works, we emphasize the use of APDs instead of photomultiplier tubes to detect the return signal and the application of the system to measure not only hard targets, but also medium-range aerosols and clouds. We have developed an experimental prototype to evaluate the behavior of the system under different environmental conditions. Experimental results provided by the prototype are presented and discussed.

Compact, Engineered, 2-Micron Coherent Doppler Wind Lidar Prototype for Field and Airborne Validation: Doppler Aerosol WiNd Lidar (DAWN). Interim Review #1 (6 months)

NASA Technical Reports Server (NTRS)

Kavaya, Michael J.; Singh, Upendra N.; Koch, Grady J.; Yu, Jirong; Amzajerdian, Farzin; Trieu, Bo C.; Petros, Mulugeta

2006-01-01

A new project, selected in 2005 by NASA's Science Mission Directorate (SMD), under the Instrument Incubator Program (IIP), will be described. The 3-year effort is intended to design, fabricate, and demonstrate a packaged, rugged, compact, space-qualifiable coherent Doppler wind lidar (DWL) transceiver capable of future validation in an aircraft and/or Unmanned Aerial Vehicle (UAV). The state-of-the-art 2-micron coherent DWL breadboard at NASA/LaRC will be engineered and compactly packaged consistent with future aircraft flights. The packaged transceiver will be integrated into a coherent DWL system test bed at LaRC. Atmospheric wind measurements will be made to validate the packaged technology. This will greatly advance the coherent part of the hybrid DWL solution to the need for global tropospheric wind measurements.

Optimization of eyesafe avalanche photodiode lidar for automobile safety and autonomous navigation systems

NASA Astrophysics Data System (ADS)

Williams, George M.

2017-03-01

Newly emerging accident-reducing, driver-assistance, and autonomous-navigation technology for automobiles is based on real-time three-dimensional mapping and object detection, tracking, and classification using lidar sensors. Yet, the lack of lidar sensors suitable for meeting application requirements appreciably limits practical widespread use of lidar in trucking, public livery, consumer cars, and fleet automobiles. To address this need, a system-engineering perspective to eyesafe lidar-system design for high-level advanced driver-assistance sensor systems and a design trade study including 1.5-μm spot-scanned, line-scanned, and flash-lidar systems are presented. A cost-effective lidar instrument design is then proposed based on high-repetition-rate diode-pumped solid-state lasers and high-gain, low-excess-noise InGaAs avalanche photodiode receivers and focal plane arrays. Using probabilistic receiver-operating-characteristic analysis, derived from measured component performance, a compact lidar system is proposed that is capable of 220 m ranging with 5-cm accuracy, which can be readily scaled to a 360-deg field of regard.

Design and development of a compact lidar/DIAL system for aerial surveillance of urban areas

NASA Astrophysics Data System (ADS)

Gaudio, P.; Gelfusa, M.; Malizia, A.; Richetta, M.; Antonucci, A.; Ventura, P.; Murari, A.; Vega, J.

2013-10-01

Recently surveying large areas in an automatic way, for early detection of harmful chemical agents, has become a strategic objective of defence and public health organisations. The Lidar-Dial techniques are widely recognized as a cost-effective alternative to monitor large portions of the atmosphere but, up to now, they have been mainly deployed as ground based stations. The design reported in this paper concerns the development of a Lidar-Dial system compact enough to be carried by a small airplane and capable of detecting sudden releases in air of harmful and/or polluting substances. The proposed approach consists of continuous monitoring of the area under surveillance with a Lidar type measurement. Once a significant increase in the density of backscattering substances is revealed, it is intended to switch to the Dial technique to identify the released chemicals and to determine its concentration. In this paper, the design of the proposed system is described and the simulations carried out to determine its performances are reported. For the Lidar measurements, commercially available Nd- YAG laser sources have already been tested and their performances, in combination with avalanche photodiodes, have been experimentally verified to meet the required specifications. With regard to the DIAL measurements, new compact CO2 laser sources are being investigated. The most promising candidate presents an energy per pulse of about 50 mJ typical, sufficient for a range of at least 500m. The laser also provides the so called "agile tuning" option that allows to quickly tune the wavelength. To guarantee continuous, automatic surveying of large areas, innovative solutions are required for the data acquisition, self monitoring of the system and data analysis. The results of the design, the simulations and some preliminary tests illustrate the potential of the chosen, integrated approach.

Advanced 2-micron Solid-state Laser for Wind and CO2 Lidar Applications

NASA Technical Reports Server (NTRS)

Yu, Jirong; Trieu, Bo C.; Petros, Mulugeta; Bai, Yingxin; Petzar, Paul J.; Koch, Grady J.; Singh, Upendra N.; Kavaya, Michael J.

2006-01-01

Significant advancements in the 2-micron laser development have been made recently. Solid-state 2-micron laser is a key subsystem for a coherent Doppler lidar that measures the horizontal and vertical wind velocities with high precision and resolution. The same laser, after a few modifications, can also be used in a Differential Absorption Lidar (DIAL) system for measuring atmospheric CO2 concentration profiles. The world record 2-micron laser energy is demonstrated with an oscillator and two amplifiers system. It generates more than one joule per pulse energy with excellent beam quality. Based on the successful demonstration of a fully conductive cooled oscillator by using heat pipe technology, an improved fully conductively cooled 2-micron amplifier was designed, manufactured and integrated. It virtually eliminates the running coolant to increase the overall system efficiency and reliability. In addition to technology development and demonstration, a compact and engineering hardened 2-micron laser is under development. It is capable of producing 250 mJ at 10 Hz by an oscillator and one amplifier. This compact laser is expected to be integrated to a lidar system and take field measurements. The recent achievements push forward the readiness of such a laser system for space lidar applications. This paper will review the developments of the state-of-the-art solid-state 2-micron laser.

A compact led lidar system fitted for a mars rover - design and ground experiment

NASA Astrophysics Data System (ADS)

Ong, Prane Mariel B.; Shiina, Tatsuo; Manago, Naohiro; Kuze, Hiroaki; Senshu, Hiroki; Otobe, Naohito; Hashimoto, George; Kawabata, Yasuhiro

2018-04-01

A compact LED lidar was constructed and fieldtested with the aim to observe the Mars' dust devils. To be able to fit it on the Mars rover, a specialized Cassegrain telescope was designed to be within a 10 cm-cube, with a field of view of 3mrad. The transmitter has 385 nm LED light source with 3 cmϕ opening, 70mrad divergence, 0.75W (7.5nJ/10ns) pulse power, and 500 kHz repetition frequency. The configuration of the optical system is biaxial to easily configure the overlap between their optical axes.

Langley Mobile Ozone Lidar: Ozone and Aerosol Atmospheric Profiling for Air Quality Research

NASA Technical Reports Server (NTRS)

De Young, Russell; Carrion, William; Ganoe, Rene; Pliutau, Denis; Gronoff, Guillaume; Berkoff, Timothy; Kuang, Shi

2017-01-01

The Langley mobile ozone lidar (LMOL) is a mobile ground-based ozone lidar system that consists of a pulsed UV laser producing two UV wavelengths of 286 and 291 nm with energy of approximately 0.2 mJ/pulse 0.2 mJ/pulse and repetition rate of 1 kHz. The 527 nm pump laser is also transmitted for aerosol measurements. The receiver consists of a 40 cm parabolic telescope, which is used for both backscattered analog and photon counting. The lidar is very compact and highly mobile. This demonstrates the utility of very small lidar systems eventually leading to space-based ozone lidars. The lidar has been validated by numerous ozonesonde launches and has provided ozone curtain profiles from ground to approximately 4 km in support of air quality field missions.

Development of Raman-Mie lidar system for aerosol and water vapor profiling

NASA Astrophysics Data System (ADS)

Deng, Qian; Wang, Zhenzhu; Xu, Jiwei; Tan, Min; Wu, Decheng; Xie, Chenbo; Liu, Dong; Wang, Yingjian

2018-03-01

Aerosol and water vapor are two important atmospheric parameters. The accurate quantification of diurnal variation of these parameters are very useful for environment assessment and climate change studies. A moveable, compact and unattended lidar system based on modular design is developed for aerosol extinction coefficients and water vapor mixing ratios measurements. In the southern suburbs of Beijing, the continuous observation was carried out by this lidar since the middle of the year of 2017. The lidar equipment is presented and the case study is also described in this paper. The observational results show that the lidar kept a very good status from the long-time continuous measurements which is suitable for networking especially in meteorological research field.

Low-pass parabolic FFT filter for airborne and satellite lidar signal processing.

PubMed

Jiao, Zhongke; Liu, Bo; Liu, Enhai; Yue, Yongjian

2015-10-14

In order to reduce random errors of the lidar signal inversion, a low-pass parabolic fast Fourier transform filter (PFFTF) was introduced for noise elimination. A compact airborne Raman lidar system was studied, which applied PFFTF to process lidar signals. Mathematics and simulations of PFFTF along with low pass filters, sliding mean filter (SMF), median filter (MF), empirical mode decomposition (EMD) and wavelet transform (WT) were studied, and the practical engineering value of PFFTF for lidar signal processing has been verified. The method has been tested on real lidar signal from Wyoming Cloud Lidar (WCL). Results show that PFFTF has advantages over the other methods. It keeps the high frequency components well and reduces much of the random noise simultaneously for lidar signal processing.

Holographic Optical Elements as Scanning Lidar Telescopes

NASA Technical Reports Server (NTRS)

Schwemmer, Geary K.; Rallison, Richard D.; Wilkerson, Thomas D.; Guerra, David V.

2003-01-01

We have investigated and developed the use of holographic optical elements (HOE) and holographic transmission gratings for scanning lidar telescopes. By rotating a flat HOE in its own plane with the focal spot on the rotation axis, a very simple and compact conical scanning telescope is possible. We developed and tested transmission and reflection HOES for use with the first three harmonics of Nd:YAG lasers, and designed, built, and tested two lidar systems based on this technology.

Measurements of particle backscatter, extinction, and lidar ratio at 1064 nm with the rotational raman method in Polly-XT

NASA Astrophysics Data System (ADS)

Engelmann, Ronny; Haarig, Moritz; Baars, Holger; Ansmann, Albert; Kottas, Michael; Marinou, Eleni

2018-04-01

We replaced a 1064-nm interference filter of a Polly-XT lidar system by a 1058-nm filter to observe pure rotational Raman backscattering from atmospheric Nitrogen and Oxygen. Polly-XT is compact Raman lidar with a Nd:YAG laser (20 Hz, 200 mJ at 1064 nm) and a 30-cm telescope mirror which applies photomultipliers in photoncounting mode. We present the first measured signals at 1058 nm and the derived extinction profile from measurements aboard RV Polarstern and in Leipzig. In combination with another Polly-XT system we could also derive particle backscatter and lidar ratio profiles at 1064 nm.

Single-Mode, High Repetition Rate, Compact Ho:YLF Laser for Space-Borne Lidar Applications

NASA Technical Reports Server (NTRS)

Bai, Yingxin; Yu, Jirong; Wong, Teh-Hwa; Chen, Songsheng; Petros, Mulugeta; Singh, Upendra N.

2014-01-01

A single transverse/longitudinal mode, compact Q-switched Ho:YLF laser has been designed and demonstrated for space-borne lidar applications. The pulse energy is between 34-40 mJ for 100-200 Hz operation. The corresponding peak power is >1 MW.

Wind Measurements from a High Energy, Pulsed, 2-Micron, Coherent-Detection Doppler Lidar and Intercomparison with other sensors deployed during Field Campaign

NASA Astrophysics Data System (ADS)

Singh, Upendra; Koch, Grady; Kavaya, Michael; Yu, Jirong; Beyon, Jeffrey; Demoz, Belay

2010-05-01

This paper presents an overview of 2-micron laser transmitter development at NASA Langley Research Center (LaRC) for coherent-detection lidar profiling of winds. The novel high-energy, 2-micron, Ho:Tm:LuLiF laser technology developed at NASA Langley was employed to study laser technology currently envisioned by NASA for future global coherent Doppler lidar winds measurement. The 250 mJ, 10 Hz laser was designed as an integral part of a compact lidar transceiver developed for future aircraft flight. Ground-based wind profiles made with this transceiver will be presented. NASA Langley is currently funded to build complete Doppler lidar systems using this transceiver for the DC-8 and WB-57 aircraft. The WB-57 flights will present a more severe environment and will require autonomous operation of the lidar system. The DC-8 lidar system is a likely component of future NASA hurricane research. It will include real-time data processing and display, as well as full data archiving. The LaRC mobile lidar was deployed at Howard University facility in Beltsville, Maryland as part of NASA HQ funded (ROSES-2007, Wind Lidar Science Proposal entitled "Intercomparison of Multiple Lidars for Wind Measurements). During the campaign, testing of the lidar was combined with a field campaign to operate a 2-micron coherent lidar alongside a 355-nm direct detection lidar to demonstrate the hybrid wind lidar concept. Besides lidar, many other meteorological sensors were located at the campaign site, including wind measuring balloon sondes, sonic and propeller anemometers mounted on a tower, and a 915-MHz radio acoustic sounding system. Comparisons among these wind measurement sensors will be presented at the conference.

CELiS (Compact Eyesafe Lidar System), a portable 1.5 μm elastic lidar system for rapid aerosol concentration measurement: Part 1, Instrument Design and Operation

NASA Astrophysics Data System (ADS)

Bird, A. W.; Wojcik, M.; Moore, K. D.; Lemon, R.

2014-12-01

CELiS (Compact Eyesafe Lidar System) is an elastic lidar system conceived for the purpose of monitoring air quality environmental compliance regarding particulate matter (PM) generated from off-road use of wheeled and tracked vehicles. CELiS is a prototype instrument development by the Space Dynamics Laboratory to demonstrate a small, low power, eye-safe lidar system capable of monitoring PM fence-line concentration of fugitive dust from off-road vehicle activity as part of the SERDP (Strategic Environmental Research and Development Program) Measurement and Modeling of Fugitive Dust Emission from Off-Road Department of Defense Activities program. CELiS is small, lightweight and easily transportable for quick setup and measurement of PM concentration and emissions. The instrument is mounted on Moog Quickset pan and tilt positioner. Ground support equipment includes portable racks with laser power and cooler, power supplies, readout electronics and computer. The complete CELiS instrument weighs less than 300 lbs., is less than 1 cubic meters in volume and uses 700 W of 120V AC power. CELiS has a working range of better than 6km and a range resolution of 1.5m-6m. CELiS operates in a biaxial configuration at the 1.5μm eyesafe wavelength. The receiver is an off-axis parabolic (OAP) telescope, aft-optics and alignment assembly and InGaAs APD detector readout. The transmitter is a 20Hz PRF - 25mJ Quantel 1.574 μm laser with a 20x beam expander. Both the receiver and transmitter are mounted on a carbon fiber optical breadboard with a custom mounting solution to minimize misalignment due to thermal operating range (0-40 C) and pointing vectors. Any lidar system used to monitor fence-line PM emissions related to off-road training activities will be subject to a strict eye-safety requirement to protect both troops and wildlife. CELiS is eyesafe at the output aperture. CELiS has participated in two Dugway Proving Ground Lidar exercises performing within expectations. Retrieval of particulate matter concentration is presented in companion poster by K. Moore.

Design of Advanced Atmospheric Water Vapor Differential Absorption Lidar (DIAL) Detection System

NASA Technical Reports Server (NTRS)

Refaat, Tamer F.; Luck, William S., Jr.; DeYoung, Russell J.

1999-01-01

The measurement of atmospheric water vapor is very important for understanding the Earth's climate and water cycle. The lidar atmospheric sensing experiment (LASE) is an instrument designed and operated by the Langley Research Center for high precision water vapor measurements. The design details of a new water vapor lidar detection system that improves the measurement sensitivity of the LASE instrument by a factor of 10 are discussed. The new system consists of an advanced, very low noise, avalanche photodiode (APD) and a state-of-the-art signal processing circuit. The new low-power system is also compact and lightweight so that it would be suitable for space flight and unpiloted atmospheric vehicles (UAV) applications. The whole system is contained on one small printed circuit board (9 x 15 sq cm). The detection system is mounted at the focal plane of a lidar receiver telescope, and the digital output is read by a personal computer with a digital data acquisition card.

Real-time computational photon-counting LiDAR

NASA Astrophysics Data System (ADS)

Edgar, Matthew; Johnson, Steven; Phillips, David; Padgett, Miles

2018-03-01

The availability of compact, low-cost, and high-speed MEMS-based spatial light modulators has generated widespread interest in alternative sampling strategies for imaging systems utilizing single-pixel detectors. The development of compressed sensing schemes for real-time computational imaging may have promising commercial applications for high-performance detectors, where the availability of focal plane arrays is expensive or otherwise limited. We discuss the research and development of a prototype light detection and ranging (LiDAR) system via direct time of flight, which utilizes a single high-sensitivity photon-counting detector and fast-timing electronics to recover millimeter accuracy three-dimensional images in real time. The development of low-cost real time computational LiDAR systems could have importance for applications in security, defense, and autonomous vehicles.

Holographic Airborne Rotating Lidar Instrument Experiment (HARLIE)

NASA Technical Reports Server (NTRS)

Schwemmer, Geary K.

1998-01-01

Scanning holographic lidar receivers are currently in use in two operational lidar systems, PHASERS (Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing) and now HARLIE (Holographic Airborne Rotating Lidar Instrument Experiment). These systems are based on volume phase holograms made in dichromated gelatin (DCG) sandwiched between 2 layers of high quality float glass. They have demonstrated the practical application of this technology to compact scanning lidar systems at 532 and 1064 nm wavelengths, the ability to withstand moderately high laser power and energy loading, sufficient optical quality for most direct detection systems, overall efficiencies rivaling conventional receivers, and the stability to last several years under typical lidar system environments. Their size and weight are approximately half of similar performing scanning systems using reflective optics. The cost of holographic systems will eventually be lower than the reflective optical systems depending on their degree of commercialization. There are a number of applications that require or can greatly benefit from a scanning capability. Several of these are airborne systems, which either use focal plane scanning, as in the Laser Vegetation Imaging System or use primary aperture scanning, as in the Airborne Oceanographic Lidar or the Large Aperture Scanning Airborne Lidar. The latter class requires a large clear aperture opening or window in the aircraft. This type of system can greatly benefit from the use of scanning transmission holograms of the HARLIE type because the clear aperture required is only about 25% larger than the collecting aperture as opposed to 200-300% larger for scan angles of 45 degrees off nadir.

Doppler Lidar for Wind Measurements on Venus

NASA Technical Reports Server (NTRS)

Singh, Upendra N.; Emmitt, George D.; Yu, Jirong; Kavaya, Michael J.

2010-01-01

NASA Langley Research Center has a long history of developing 2-micron laser transmitter for wind sensing. With support from NASA Laser Risk Reduction Program (LRRP) and Instrument Incubator Program (IIP), NASA Langley Research Center has developed a state-of-the-art compact lidar transceiver for a pulsed coherent Doppler lidar system for wind measurement. The transmitter portion of the transceiver employs the high-pulse-energy, Ho:Tm:LuLiF, partially conductively cooled laser technology developed at NASA Langley. The transceiver is capable of 250 mJ pulses at 10 Hz. It is very similar to the technology envisioned for coherent Doppler lidar wind measurements from Earth and Mars orbit. The transceiver is coupled to the large optics and data acquisition system in the NASA Langley VALIDAR mobile trailer. The large optics consists of a 15-cm off-axis beam expanding telescope, and a full-hemispheric scanner. Vertical and horizontal vector winds are measured, as well as relative backscatter. The data acquisition system employs frequency domain velocity estimation and pulse accumulation. It permits real-time display of the processed winds and archival of all data. This lidar system was recently deployed at Howard University facility in Beltsville, Mary-land, along with other wind lidar systems. Coherent Doppler wind lidar ground-based wind measurements and comparisons with other sensors will be presented. A simulation and data product for wind measurement at Venus will be presented.

New laser design for NIR lidar applications

NASA Astrophysics Data System (ADS)

Vogelmann, H.; Trickl, T.; Perfahl, M.; Biggel, S.

2018-04-01

Recently, we quantified the very high spatio-temporal short term variability of tropospheric water vapor in a three dimensional study [1]. From a technical point of view this also depicted the general requirement of short integration times for recording water-vapor profiles with lidar. For this purpose, the only suitable technique is the differential absorption lidar (DIAL) working in the near-infrared (NIR) spectral region. The laser emission of most water vapor DIAL systems is generated by Ti:sapphire or alexandrite lasers. The water vapor absorption band at 817 nm is predominated for the use of Ti:sapphire. We present a new concept of transversely pumping in a Ti:Sapphire amplification stage as well as a compact laser design for the generation of single mode NIR pulses with two different DIAL wavelengths inside a single resonator. This laser concept allows for high output power due to repetitions rates up to 100Hz or even more. It is, because of its compactness, also suitable for mobile applications.

Feasibility Study For A Spaceborne Ozone/Aerosol Lidar System

NASA Technical Reports Server (NTRS)

Campbell, Richard E.; Browell, Edward V.; Ismail, Syed; Dudelzak, Alexander E.; Carswell, Allan I.; Ulitsky, Arkady

1997-01-01

Because ozone provides a shield against harmful ultraviolet radiation, determines the temperature profile in the stratosphere, plays important roles in tropospheric chemistry and climate, and is a health risk near the surface, changes in natural ozone layers at different altitudes and their global impact are being intensively researched. Global ozone coverage is currently provided by passive optical and microwave satellite sensors that cannot deliver high spatial resolution measurements and have particular limitations in the troposphere. Vertical profiling DIfferential Absorption Lidars (DIAL) have shown excellent range-resolved capabilities, but these systems have been large, inefficient, and have required continuous technical attention for long term operations. Recently, successful, autonomous DIAL measurements have been performed from a high-altitude aircraft (LASE - Lidar Atmospheric Sensing Experiment), and a space-qualified aerosol lidar system (LITE - Laser In-space Technology Experiment) has performed well on Shuttle. Based on the above successes, NASA and the Canadian Space Agency are jointly studying the feasibility of developing ORACLE (Ozone Research with Advanced Cooperative Lidar Experiments), an autonomously operated, compact DIAL instrument to be placed in orbit using a Pegasus class launch vehicle.

Development of a solid-state sodium Doppler lidar using an all-fiber-coupled injection seeding unit for simultaneous temperature and wind measurements in the mesopause region

NASA Astrophysics Data System (ADS)

Yang, Guotao; Xia, Yuan; Cheng, Xuewu; Du, Lifang; Wang, Jihong; Xun, Yuchang

2017-04-01

We present a solid-state sodium (Na) Doppler lidar developed at YanQing Station, Beijing, China (40°N, 116°E) to achieve simultaneous wind and temperature measurements of mesopause region. The 589nm pulse laser is produced by two injection seeded 1064nm and 1319nm Nd:YAG pulse lasers using the sum-frequency generation (SFG) technique. An all-fiber-coupled seeding laser unit was designed to enable absolute laser frequency locking and cycling the measurements among three different operating frequencies. Experimental observations were carried out using this Na lidar system and the preliminary results were described and compared with the temperature of the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) and the horizontal wind of the meteor Radar, demonstrating the reliability and good performance of this lidar system. The all-fiber-coupled injection seeding configuration together with the solid-state Nd:YAG lasers make the Na Doppler lidar more compact and greatly reduce the system maintenance, which is conducive to transportable and unattended operation.

Solid-State 2-Micron Laser Transmitter Advancement for Wind and Carbon Dioxide Measurements From Ground, Airborne, and Space-Based Lidar Systems

NASA Technical Reports Server (NTRS)

Singh, Upendra N.; Kavaya, Michael J.; Koch, Grady; Yu, Jirong; Ismail, Syed

2008-01-01

NASA Langley Research Center has been developing 2-micron lidar technologies over a decade for wind measurements, utilizing coherent Doppler wind lidar technique and carbon dioxide measurements, utilizing Differential Absorption Lidar (DIAL) technique. Significant advancements have been made towards developing state-of-the-art technologies towards laser transmitters, detectors, and receiver systems. These efforts have led to the development of solid-state lasers with high pulse energy, tunablility, wavelength-stability, and double-pulsed operation. This paper will present a review of these technological developments along with examples of high resolution wind and high precision CO2 DIAL measurements in the atmosphere. Plans for the development of compact high power lasers for applications in airborne and future space platforms for wind and regional to global scale measurement of atmospheric CO2 will also be discussed.

Helicopter Flight Test of a Compact, Real-Time 3-D Flash Lidar for Imaging Hazardous Terrain During Planetary Landing

NASA Technical Reports Server (NTRS)

Roback, VIncent E.; Amzajerdian, Farzin; Brewster, Paul F.; Barnes, Bruce W.; Kempton, Kevin S.; Reisse, Robert A.; Bulyshev, Alexander E.

2013-01-01

A second generation, compact, real-time, air-cooled 3-D imaging Flash Lidar sensor system, developed from a number of cutting-edge components from industry and NASA, is lab characterized and helicopter flight tested under the Autonomous Precision Landing and Hazard Detection and Avoidance Technology (ALHAT) project. The ALHAT project is seeking to develop a guidance, navigation, and control (GN&C) and sensing system based on lidar technology capable of enabling safe, precise crewed or robotic landings in challenging terrain on planetary bodies under any ambient lighting conditions. The Flash Lidar incorporates a 3-D imaging video camera based on Indium-Gallium-Arsenide Avalanche Photo Diode and novel micro-electronic technology for a 128 x 128 pixel array operating at a video rate of 20 Hz, a high pulse-energy 1.06 µm Neodymium-doped: Yttrium Aluminum Garnet (Nd:YAG) laser, a remote laser safety termination system, high performance transmitter and receiver optics with one and five degrees field-of-view (FOV), enhanced onboard thermal control, as well as a compact and self-contained suite of support electronics housed in a single box and built around a PC-104 architecture to enable autonomous operations. The Flash Lidar was developed and then characterized at two NASA-Langley Research Center (LaRC) outdoor laser test range facilities both statically and dynamically, integrated with other ALHAT GN&C subsystems from partner organizations, and installed onto a Bell UH-1H Iroquois "Huey" helicopter at LaRC. The integrated system was flight tested at the NASA-Kennedy Space Center (KSC) on simulated lunar approach to a custom hazard field consisting of rocks, craters, hazardous slopes, and safe-sites near the Shuttle Landing Facility runway starting at slant ranges of 750 m. In order to evaluate different methods of achieving hazard detection, the lidar, in conjunction with the ALHAT hazard detection and GN&C system, operates in both a narrow 1deg FOV raster-scanning mode in which successive, gimbaled images of the hazard field are mosaicked together as well as in a wider, 4.85deg FOV staring mode in which digital magnification, via a novel 3-D superresolution technique, is used to effectively achieve the same spatial precision attained with the more narrow FOV optics. The lidar generates calibrated and corrected 3-D range images of the hazard field in real-time and passes them to the ALHAT Hazard Detection System (HDS) which stitches the images together to generate on-the-fly Digital Elevation Maps (DEM's) and identifies hazards and safe-landing sites which the ALHAT GN&C system can then use to guide the host vehicle to a safe landing on the selected site. Results indicate that, for the KSC hazard field, the lidar operational range extends from 100m to 1.35 km for a 30 degree line-of-sight angle and a range precision as low as 8 cm which permits hazards as small as 25 cm to be identified. Based on the Flash Lidar images, the HDS correctly found and reported safe sites in near-real-time during several of the flights. A follow-on field test, planned for 2013, seeks to complete the closing of the GN&C loop for fully-autonomous operations on-board the Morpheus robotic, rocket-powered, free-flyer test bed in which the ALHAT system would scan the KSC hazard field (which was vetted during the present testing) and command the vehicle to landing on one of the selected safe sites.

Design and Demonstration of a Miniature Lidar System for Rover Applications

NASA Technical Reports Server (NTRS)

Robinson, Benjamin

2011-01-01

Public awareness of harmful human environmental effects such as global warming has increased greatly in recent years and researchers have increased their efforts in gaining more knowledge about the Earth's atmosphere. Natural and man-made processes pose threats to the environment and human life, so knowledge of all atmospheric processes is necessary. Ozone and aerosols are important factors in many atmospheric processes and active remote sensing techniques provide a way to analyze their quantity and distribution. A compact ground-based lidar system for a robotic platform meant for atmospheric aerosol measurements was designed, tested, and evaluated. The system will eventually be deployed for ozone and aerosol measurements in Mars and lunar missions to improve our knowledge and understanding of atmospheres on Mars and the Moon. Atmospheric testing was performed to test the operability of the receiver system to acquire the lidar return signal from clouds and aerosols.

Flash LIDAR Systems for Planetary Exploration

NASA Astrophysics Data System (ADS)

Dissly, Richard; Weinberg, J.; Weimer, C.; Craig, R.; Earhart, P.; Miller, K.

2009-01-01

Ball Aerospace offers a mature, highly capable 3D flash-imaging LIDAR system for planetary exploration. Multi mission applications include orbital, standoff and surface terrain mapping, long distance and rapid close-in ranging, descent and surface navigation and rendezvous and docking. Our flash LIDAR is an optical, time-of-flight, topographic imaging system, leveraging innovations in focal plane arrays, readout integrated circuit real time processing, and compact and efficient pulsed laser sources. Due to its modular design, it can be easily tailored to satisfy a wide range of mission requirements. Flash LIDAR offers several distinct advantages over traditional scanning systems. The entire scene within the sensor's field of view is imaged with a single laser flash. This directly produces an image with each pixel already correlated in time, making the sensor resistant to the relative motion of a target subject. Additionally, images may be produced at rates much faster than are possible with a scanning system. And because the system captures a new complete image with each flash, optical glint and clutter are easily filtered and discarded. This allows for imaging under any lighting condition and makes the system virtually insensitive to stray light. Finally, because there are no moving parts, our flash LIDAR system is highly reliable and has a long life expectancy. As an industry leader in laser active sensor system development, Ball Aerospace has been working for more than four years to mature flash LIDAR systems for space applications, and is now under contract to provide the Vision Navigation System for NASA's Orion spacecraft. Our system uses heritage optics and electronics from our star tracker products, and space qualified lasers similar to those used in our CALIPSO LIDAR, which has been in continuous operation since 2006, providing more than 1.3 billion laser pulses to date.

Data Acquisition and Processing System for Airborne Wind Profiling with a Pulsed, 2-Micron, Coherent-Detection, Doppler Lidar System

NASA Technical Reports Server (NTRS)

Beyon, J. Y.; Koch, G. J.; Kavaya, M. J.

2010-01-01

A data acquisition and signal processing system is being developed for a 2-micron airborne wind profiling coherent Doppler lidar system. This lidar, called the Doppler Aerosol Wind Lidar (DAWN), is based on a Ho:Tm:LuLiF laser transmitter and 15-cm diameter telescope. It is being packaged for flights onboard the NASA DC-8, with the first flights in the summer of 2010 in support of the NASA Genesis and Rapid Intensification Processes (GRIP) campaign for the study of hurricanes. The data acquisition and processing system is housed in a compact PCI chassis and consists of four components such as a digitizer, a digital signal processing (DSP) module, a video controller, and a serial port controller. The data acquisition and processing software (DAPS) is also being developed to control the system including real-time data analysis and display. The system detects an external 10 Hz trigger pulse and initiates the data acquisition and processing process, and displays selected wind profile parameters such as Doppler shift, power distribution, wind directions and velocities. Doppler shift created by aircraft motion is measured by an inertial navigation/GPS sensor and fed to the signal processing system for real-time removal of aircraft effects from wind measurements. A general overview of the system and the DAPS as well as the coherent Doppler lidar system is presented in this paper.

Ground-Based Lidar for Atmospheric Boundary Layer Ozone Measurements

NASA Technical Reports Server (NTRS)

Kuang, Shi; Newchurch, Michael J.; Burris, John; Liu, Xiong

2013-01-01

Ground-based lidars are suitable for long-term ozone monitoring as a complement to satellite and ozonesonde measurements. However, current ground-based lidars are unable to consistently measure ozone below 500 m above ground level (AGL) due to both engineering issues and high retrieval sensitivity to various measurement errors. In this paper, we present our instrument design, retrieval techniques, and preliminary results that focus on the high-temporal profiling of ozone within the atmospheric boundary layer (ABL) achieved by the addition of an inexpensive and compact mini-receiver to the previous system. For the first time, to the best of our knowledge, the lowest, consistently achievable observation height has been extended down to 125 m AGL for a ground-based ozone lidar system. Both the analysis and preliminary measurements demonstrate that this lidar measures ozone with a precision generally better than 10% at a temporal resolution of 10 min and a vertical resolution from 150 m at the bottom of the ABL to 550 m at the top. A measurement example from summertime shows that inhomogeneous ozone aloft was affected by both surface emissions and the evolution of ABL structures.

Measurements of Water Vapor Profiles with Compact DIAL in the Tokyo Metropolitan Area

NASA Astrophysics Data System (ADS)

Abo, Makoto; Sakai, Tetsu; Le Hoai, Phong Pham; Shibata, Yasukuni; Nagasawa, Chikao

2018-04-01

In recent years, the frequency of occurrence of locally heavy rainfall that can cause extensive damages, has been increasing in Japan. For early prediction of heavy rainfall, it is useful to measure the water vapor vertical distribution upwind cumulus convection beforehand. For that purpose, we have been developing compact water vapor differential absorption lidar (DIAL). We show the results of the measurements with lidar in summer when the local heavy rainfall frequently occurs in Japan. We also show the preliminary result of the assimilation of the lidar data to the numerical model and impact on the heavy rainfall prediction.

New Mobile Lidar Systems Aboard Ultra-Light Aircrafts

NASA Astrophysics Data System (ADS)

Chazette, Patrick; Shang, Xiaoxia; Totems, Julien; Marnas, Fabien; Sanak, Joseph

2013-04-01

Two lidar systems embedded on ultra light aircraft (ULA) flew over the Rhone valley, south-east of France, to characterize the vertical extend of pollution aerosols in this area influenced by large industrial sites. The main industrial source is the Etang de Berre (43°28' N, 5°01' E), close to Marseille city. The emissions are mainly due to metallurgy and petrochemical factories. Traffic related to Marseille's area contribute to pollution with its ~1500000 inhabitants. Note that the maritime traffic close to Marseille may play an important role due to its position as the leading French harbor . For the previous scientific purpose and for the first time on ULA, we flew a mini-N2 Raman lidar system to help the assessment of the aerosol optical properties. Another Ultra-Violet Rayleigh-Mie lidar has been integrated aboard a second ULA. The lidars are compact and eye safe instruments. They operate at the wavelength of 355 nm with a sampling along the line-of-sight of 0.75 m. Different flights plans were tested to use the two lidars in synergy. We will present the different approaches and discuss both their advantages and limitations. Acknowledgements: the lidar systems have been developed by CEA. They have been deployed with the support of FERRING France. We acknowledge the ULA pilots Franck Toussaint, François Bernard and José Coutet, and the Air Creation ULA Company for logistical help during the ULA campaign.

Wind Profiling from a High Energy, Pulsed, 2-Micron, Coherent-Detection Doppler Lidar during Field Campaign

NASA Astrophysics Data System (ADS)

Singh, U. N.; Koch, G. J.; Kavaya, M. J.; Yu, J.; Beyon, J. Y.; Demoz, B.

2009-12-01

NASA Langley Research Center has a long history of developing 2-micron laser transmitter for wind sensing. With support from NASA Laser Risk Reduction Program (LRRP) and Instrument Incubator Program (IIP), NASA Langley Research Center has developed a state-of-the-art compact lidar transceiver for a pulsed coherent Doppler lidar system for wind measurement. The transmitter portion of the transceiver employs the high-pulse-energy, Ho:Tm:LuLiF, partially conductively cooled laser technology developed at NASA Langley. The transceiver is capable of 250 mJ pulses at 10 Hz. It is very similar to the technology envisioned for coherent Doppler lidar wind measurements from Earth and Mars orbit. The transceiver is coupled to the large optics and data acquisition system in the NASA Langley VALIDAR mobile trailer. The large optics consists of a 15-cm off-axis beam expanding telescope, and a full-hemispheric scanner. Vertical and horizontal vector winds are measured, as well as relative backscatter. The data acquisition system employs frequency domain velocity estimation and pulse accumulation. It permits real-time display of the processed winds and archival of all data. The LaRC mobile lidar was deployed at Howard University facility in Beltsville, Maryland as part of NASA HQ funded (ROSES-2007, Wind Lidar Science Proposal entitled “Intercomparison of Multiple Lidars for Wind Measurements). During the campaign, testing of the lidar was combined with a field campaign to operate a 2-μm coherent lidar alongside a 355-nm direct detection lidar to demonstrate the hybrid wind lidar concept. Besides lidar, many other meteorological sensors were located at the campaign site, including wind measuring balloon sondes, sonic and propeller anemometers mounted on a tower, and a 915-MHz radio acoustic sounding system. Comparisons among these wind measurement sensors are currently being analyzed and should be available for presentation at the Conference.

Compact high-pulse-energy ultraviolet laser source for ozone lidar measurements.

PubMed

Elsayed, Khaled A; DeYoung, Russell J; Petway, Larry B; Edwards, William C; Barnes, James C; Elsayed-Ali, Hani E

2003-11-20

An all solid-state Ti:sapphire laser differential absorption lidar transmitter was developed. This all-solid-state laser provides a compact, robust, and highly reliable laser transmitter for potential application in differential absorption lidar measurements of atmospheric ozone. Two compact, high-energy-pulsed, and injection-seeded Ti:sapphire lasers operating at a pulse repetition frequency of 30 Hz and wavelengths of 867 and 900 nm, with M2 of 1.3, have been experimentally demonstrated and their properties compared with model results. The output pulse energy was 115 mJ at 867 nm and 105 mJ at 900 nm, with a slope efficiency of 40% and 32%, respectively. At these energies, the beam quality was good enough so that we were able to achieve 30 mJ of ultraviolet laser output at 289 and 300 nm after frequency tripling with two lithium triborate nonlinear crystals.

Holographic Optical Elements as Scanning Lidar Telescopes

NASA Technical Reports Server (NTRS)

Schwemmer, Geary K.; Rallison, Richard D.; Wilkerson, Thomas D.; Guerra, David V.

2005-01-01

We have developed and investigated the use of holographic optical elements (HOEs) and holographic transmission gratings for scanning lidar telescopes. For example, rotating a flat HOE in its own plane with the focal spot on the rotation axis makes a very simple and compact conical scanning telescope. We developed and tested transmission and reflection HOEs for use at the first three harmonic wavelengths of Nd:YAG lasers. The diffraction efficiency, diffraction angle, focal length, focal spot size and optical losses were measured for several HOEs and holographic gratings, and found to be suitable for use as lidar receiver telescopes, and in many cases could also serve as the final collimating and beam steering optic for the laser transmitter. Two lidar systems based on this technology have been designed, built, and successfully tested in atmospheric science applications. This technology will enable future spaceborne lidar missions by significantly lowering the size, weight, power requirement and cost of a large aperture, narrow field of view scanning telescope.

The marbll experiment: towards a martian wind lidar

NASA Astrophysics Data System (ADS)

Määttänen, Anni; Ravetta, François; Montmessin, Franck; Bruneau, Didier; Mariscal, Jean-François; Van Haecke, Mathilde; Fayolle, Guillaume; Montaron, Christophe; Coscia, David

2018-04-01

Operating a lidar on Mars would fulfill the need of accessing wind and aerosol profiles in the atmospheric boundary layer. This is the purpose of the MARs Boundary Layer Lidar (MARBLL) instrument. We report recent developments of this compact direct-detection wind lidar designed to operate from the surface of Mars. A new laser source has been developed and an azimuthal scanning capability has been added. Preliminary results of a field campaign are presented.

Micro pulse lidar

NASA Technical Reports Server (NTRS)

Spinhirne, James D.

1993-01-01

An eye safe, compact, solid state lidar for profiling atmospheric cloud and aerosol scattering has been demonstrated. The transmitter of the micropulse lidar is a diode pumped micro-J pulse energy, high repetition rate Nd:YLF laser. Eye safety is obtained through beam expansion. The receiver employs a photon counting solid state Geiger mode avalanche photodiode detector. Data acquisition is by a single card multichannel scaler. Daytime background induced quantum noise is controlled by a narrow receiver field-of-view and a narrow bandwidth temperature controlled interference filter. Dynamic range of the signal is limited by optical geometric signal compression. Signal simulations and initial atmospheric measurements indicate that systems built on the micropulse lidar concept are capable of detecting and profiling all significant cloud and aerosol scattering through the troposphere and into the stratosphere. The intended applications are scientific studies and environmental monitoring which require full time, unattended measurements of the cloud and aerosol height structure.

Design and Demonstration of a Miniature Lidar System for Rover Applications

NASA Technical Reports Server (NTRS)

Robinson, Benjamin

2011-01-01

Public awareness of harmful human environmental effects such as global warming has increased greatly in recent years and researchers have increased their efforts in gaining more knowledge about the Earth s atmosphere. Natural and man-made processes pose threats to the environment and human life, so knowledge of all atmospheric processes is necessary. Ozone and aerosols are important factors in many atmospheric processes and active remote sensing techniques provide a way to analyze their quantity and distribution. A compact ground-based lidar system for a robotic platform meant for atmospheric aerosol measurements was designed, tested, and evaluated. The system will eventually be deployed for ozone and aerosol measurements in Mars and lunar missions to improve our knowledge and understanding of atmospheres on Mars and the Moon. All of the major subsystems were described in detail and atmospheric testing was performed to test the operability of the receiver system to acquire the lidar return signal from clouds and aerosols. The measured backscattered results are discussed and compared with theoretical results.

Compact and Rugged Transceiver for Coherent Doppler Wind Lidar Applications in Space

NASA Technical Reports Server (NTRS)

Kavaya, Michael J.; Koch, Grady J.; Yu, Jirong; Amzajerdian, Farzin; Singh, Upendra N.; Trieu, Bo C.; Modlin, Ed A.; Petros, Mulugeta; Bai, Yingxin; Reithmaier, Karl;

Lidar Remote Sensing for Industry and Environment Monitoring

NASA Technical Reports Server (NTRS)

Singh, Upendra N. (Editor); Itabe, Toshikazu (Editor); Sugimoto, Nobuo (Editor)

2000-01-01

Contents include the following: 1. Keynote paper: Overview of lidar technology for industrial and environmental monitoring in Japan. 2. lidar technology I: NASA's future active remote sensing mission for earth science. Geometrical detector consideration s in laser sensing application (invited paper). 3. Lidar technology II: High-power femtosecond light strings as novel atmospheric probes (invited paper). Design of a compact high-sensitivity aerosol profiling lidar. 4. Lasers for lidars: High-energy 2 microns laser for multiple lidar applications. New submount requirement of conductively cooled laser diodes for lidar applications. 5. Tropospheric aerosols and clouds I: Lidar monitoring of clouds and aerosols at the facility for atmospheric remote sensing (invited paper). Measurement of asian dust by using multiwavelength lidar. Global monitoring of clouds and aerosols using a network of micropulse lidar systems. 6. Troposphere aerosols and clouds II: Scanning lidar measurements of marine aerosol fields at a coastal site in Hawaii. 7. Tropospheric aerosols and clouds III: Formation of ice cloud from asian dust particles in the upper troposphere. Atmospheric boundary layer observation by ground-based lidar at KMITL, Thailand (13 deg N, 100 deg. E). 8. Boundary layer, urban pollution: Studies of the spatial correlation between urban aerosols and local traffic congestion using a slant angle scanning on the research vessel Mirai. 9. Middle atmosphere: Lidar-observed arctic PSC's over Svalbard (invited paper). Sodium temperature lidar measurements of the mesopause region over Syowa Station. 10. Differential absorption lidar (dIAL) and DOAS: Airborne UV DIAL measurements of ozone and aerosols (invited paper). Measurement of water vapor, surface ozone, and ethylene using differential absorption lidar. 12. Space lidar I: Lightweight lidar telescopes for space applications (invited paper). Coherent lidar development for Doppler wind measurement from the International Space Station. 13. Space lidar II: Using coherent Doppler lidar to estimate river discharge. 14. Poster session: Lidar technology, optics for lidar. Laser for lidar. Middle atmosphere observations. Tropospheric observations (aerosols, clouds). Boundary layer, urban pollution. Differential absorption lidar. Doppler lidar. and Space lidar.

Compact high-power shipborne doppler lidar based on high spectral resolution techniques

NASA Astrophysics Data System (ADS)

Wu, Songhua; Liu, Bingyi; Dai, Guangyao; Qin, Shenguang; Liu, Jintao; Zhang, Kailin; Feng, Changzhong; Zhai, Xiaochun; Song, Xiaoquan

2018-04-01

The Compact High-Power Shipborne Doppler Wind Lidar (CHiPSDWiL) based on highspectral-resolution technique has been built up at the Ocean University of China for the measurement of the wind field and the properties of the aerosol and clouds in the troposphere. The design of the CHiPSDWiL including the transceiver, the injection seeding, the locking and the frequency measurement will be presented. Preliminary results measured by the CHiPSDWiL are provided.

Ground-based lidar for atmospheric boundary layer ozone measurements.

PubMed

Kuang, Shi; Newchurch, Michael J; Burris, John; Liu, Xiong

2013-05-20

Ground-based lidars are suitable for long-term ozone monitoring as a complement to satellite and ozonesonde measurements. However, current ground-based lidars are unable to consistently measure ozone below 500 m above ground level (AGL) due to both engineering issues and high retrieval sensitivity to various measurement errors. In this paper, we present our instrument design, retrieval techniques, and preliminary results that focus on the high-temporal profiling of ozone within the atmospheric boundary layer (ABL) achieved by the addition of an inexpensive and compact mini-receiver to the previous system. For the first time, to the best of our knowledge, the lowest, consistently achievable observation height has been extended down to 125 m AGL for a ground-based ozone lidar system. Both the analysis and preliminary measurements demonstrate that this lidar measures ozone with a precision generally better than ±10% at a temporal resolution of 10 min and a vertical resolution from 150 m at the bottom of the ABL to 550 m at the top. A measurement example from summertime shows that inhomogeneous ozone aloft was affected by both surface emissions and the evolution of ABL structures.

Lidar Characterization of Boundary Layer Transport and Mixing for Estimating Urban-Scale Greenhouse Gas Emissions

NASA Astrophysics Data System (ADS)

Hardesty, R. Michael; Brewer, W. Alan; Sandberg, Scott P.; Weickmann, Ann M.; Shepson, Paul B.; Cambaliza, Maria; Heimburger, Alexie; Davis, Kenneth J.; Lauvaux, Thomas; Miles, Natasha L.; Sarmiento, Daniel P.; Deng, A. J.; Gaudet, Brian; Karion, Anna; Sweeney, Colm; Whetstone, James

2016-06-01

A compact commercial Doppler lidar has been deployed in Indianapolis for two years to measure wind profiles and mixing layer properties as part of project to improve greenhouse measurements from large area sources. The lidar uses vertical velocity variance and aerosol structure to measure mixing layer depth. Comparisons with aircraft and the NOAA HRDL lidar generally indicate good performance, although sensitivity might be an issue under low aerosol conditions.

Fiber-based Coherent Lidar for Target Ranging, Velocimetry, and Atmospheric Wind Sensing

NASA Technical Reports Server (NTRS)

Amzajerdian, Farzin; Pierrottet, Diego

2006-01-01

By employing a combination of optical heterodyne and linear frequency modulation techniques and utilizing state-of-the-art fiber optic technologies, highly efficient, compact and reliable lidar suitable for operation in a space environment is being developed.

A Compact Airborne High Spectral Resolution Lidar for Observations of Aerosol and Cloud Optical Properties

NASA Technical Reports Server (NTRS)

Hostetler, Chris A.; Hair, John W.; Cook, Anthony L.

2002-01-01

We are in the process of developing a nadir-viewing, aircraft-based high spectral resolution lidar (HSRL) at NASA Langley Research Center. The system is designed to measure backscatter and extinction of aerosols and tenuous clouds. The primary uses of the instrument will be to validate spaceborne aerosol and cloud observations, carry out regional process studies, and assess the predictions of chemical transport models. In this paper, we provide an overview of the instrument design and present the results of simulations showing the instrument's capability to accurately measure extinction and extinction-to-backscatter ratio.

Liborg: a lidar-based robot for efficient 3D mapping

NASA Astrophysics Data System (ADS)

Vlaminck, Michiel; Luong, Hiep; Philips, Wilfried

2017-09-01

In this work we present Liborg, a spatial mapping and localization system that is able to acquire 3D models on the y using data originated from lidar sensors. The novelty of this work is in the highly efficient way we deal with the tremendous amount of data to guarantee fast execution times while preserving sufficiently high accuracy. The proposed solution is based on a multi-resolution technique based on octrees. The paper discusses and evaluates the main benefits of our approach including its efficiency regarding building and updating the map and its compactness regarding compressing the map. In addition, the paper presents a working prototype consisting of a robot equipped with a Velodyne Lidar Puck (VLP-16) and controlled by a Raspberry Pi serving as an independent acquisition platform.

Compact Ozone Lidar for Atmospheric Ozone and Aerosol Measurements

NASA Technical Reports Server (NTRS)

Marcia, Joel; DeYoung, Russell J.

2007-01-01

A small compact ozone differential absorption lidar capable of being deployed on a small aircraft or unpiloted atmospheric vehicle (UAV) has been tested. The Ce:LiCAF tunable UV laser is pumped by a quadrupled Nd:YLF laser. Test results on the laser transmitter demonstrated 1.4 W in the IR and 240 mW in the green at 1000 Hz. The receiver consists of three photon-counting channels, which are a far field PMT, a near field UV PMT, and a green PMT. Each channel was tested for their saturation characteristics.

Optical amplifiers for coherent lidar

NASA Technical Reports Server (NTRS)

Fork, Richard

1996-01-01

We examine application of optical amplification to coherent lidar for the case of a weak return signal (a number of quanta of the return optical field close to unity). We consider the option that has been explored to date, namely, incorporation of an optical amplifier operated in a linear manner located after reception of the signal and immediately prior to heterodyning and photodetection. We also consider alternative strategies where the coherent interaction, the nonlinear processes, and the amplification are not necessarily constrained to occur in the manner investigated to date. We include the complications that occur because of mechanisms that occur at the level of a few, or one, quantum excitation. Two factors combine in the work to date that limit the value of the approach. These are: (1) the weak signal tends to require operation of the amplifier in the linear regime where the important advantages of nonlinear optical processing are not accessed, (2) the linear optical amplifier has a -3dB noise figure (SN(out)/SN(in)) that necessarily degrades the signal. Some improvement is gained because the gain provided by the optical amplifier can be used to overcome losses in the heterodyned process and photodetection. The result, however, is that introduction of an optical amplifier in a well optimized coherent lidar system results in, at best, a modest improvement in signal to noise. Some improvement may also be realized on incorporating more optical components in a coherent lidar system for purely practical reasons. For example, more compact, lighter weight, components, more robust alignment, or more rapid processing may be gained. We further find that there remain a number of potentially valuable, but unexplored options offered both by the rapidly expanding base of optical technology and the recent investigation of novel nonlinear coherent interference phenomena occurring at the single quantum excitation level. Key findings are: (1) insertion of linear optical amplifiers in well optimized conventional lidar systems offers modest improvements, at best, (2) the practical advantages of optical amplifiers, especially fiber amplifiers, such as ease of alignment, compactness, efficiency, lightweight, etc., warrant further investigation for coherent lidar, (3) the possibility of more fully optical lidar systems should be explored, (4) advantages gained by use of coherent interference of optical fields at the level of one, or a few, signal quanta should be explored, (5) amplification without inversion, population trapping, and use of electromagnetic induced transparency warrant investigation in connection with coherent lidar, (6) these new findings are probably more applicable to earth related NASA work, although applications to deep space should not be excluded, and (7) our own work in the Ultrafast Laboratory at UAH along some of the above lines of investigation, may be useful.

SAR and LIDAR fusion: experiments and applications

NASA Astrophysics Data System (ADS)

Edwards, Matthew C.; Zaugg, Evan C.; Bradley, Joshua P.; Bowden, Ryan D.

2013-05-01

In recent years ARTEMIS, Inc. has developed a series of compact, versatile Synthetic Aperture Radar (SAR) systems which have been operated on a variety of small manned and unmanned aircraft. The multi-frequency-band SlimSAR has demonstrated a variety of capabilities including maritime and littoral target detection, ground moving target indication, polarimetry, interferometry, change detection, and foliage penetration. ARTEMIS also continues to build upon the radar's capabilities through fusion with other sensors, such as electro-optical and infrared camera gimbals and light detection and ranging (LIDAR) devices. In this paper we focus on experiments and applications employing SAR and LIDAR fusion. LIDAR is similar to radar in that it transmits a signal which, after being reflected or scattered by a target area, is recorded by the sensor. The differences are that a LIDAR uses a laser as a transmitter and optical sensors as a receiver, and the wavelengths used exhibit a very different scattering phenomenology than the microwaves used in radar, making SAR and LIDAR good complementary technologies. LIDAR is used in many applications including agriculture, archeology, geo-science, and surveying. Some typical data products include digital elevation maps of a target area and features and shapes extracted from the data. A set of experiments conducted to demonstrate the fusion of SAR and LIDAR data include a LIDAR DEM used in accurately processing the SAR data of a high relief area (mountainous, urban). Also, feature extraction is used in improving geolocation accuracy of the SAR and LIDAR data.

Laser applications in meteorology and earth and atmospheric remote sensing; Proceedings of the Meeting, Los Angeles, CA, Jan. 16-18, 1989

NASA Technical Reports Server (NTRS)

Sokoloski, Martin M. (Editor)

1989-01-01

Various papers on laser applications in meteorology and earth and atmospheric remote sensing are presented. The individual topics addressed include: solid state lasers for the mid-IR region, tunable chromium lasers, GaInAsSb/AlGaAsSb injection lasers for remote sensing applications, development and design of an airborne autonomous wavemeter for laser tuning, fabrication of lightweight Si/SiC lidar mirrors, low-cost double heterostructure and quantum-well laser array development, nonlinear optical processes for the mid-IR region, simulated space-based Doppler lidar performance in regions of backscatter inhomogeneities, design of CO2 recombination catalysts for closed-cycle CO2 lasers, density measurements with combined Raman-Rayleigh lidar, geodynamics applications of spaceborne laser ranging, use of aircraft laser ranging data for forest mensuration, remote active spectrometer, multiwavelngth and triple CO2 lidars for trace gas detection, analysis of laser diagnostics in plumes, laser atmospheric wind sounder, compact Doppler lidar system using commercial off-the-shelf components, and preliminary design for a laser atmospheric wind sounder.

New fiber laser for lidar developments in disaster management

NASA Astrophysics Data System (ADS)

Besson, C.; Augere, B.; Canat, G.; Cezard, N.; Dolfi-Bouteyre, A.; Fleury, D.; Goular, D.; Lombard, L.; Planchat, C.; Renard, W.; Valla, M.

2014-10-01

Recent progress in fiber technology has enabled new laser designs along with all fiber lidar architectures. Their asset is to avoid free-space optics, sparing lengthy alignment procedures and yielding compact setups that are well adapted for field operations and on board applications thanks to their intrinsic vibration-resistant architectures. We present results in remote sensing for disaster management recently achieved with fiber laser systems. Field trials of a 3-paths lidar vibrometer for the remote study of modal parameters of buildings has shown that application-related constraints were fulfilled and that the obtained results are consistent with simultaneous in situ seismic sensors measurements. Remote multi-gas detection can be obtained using broadband infrared spectroscopy. Results obtained on methane concentration measurement using an infrared supercontinuum fiber laser and analysis in the 3-4 μm band are reported. For gas flux retrieval, air velocity measurement is also required. Long range scanning all-fiber wind lidars are now available thanks to innovative laser architectures. High peak power highly coherent pulses can be extracted from Er3+:Yb3+ and Tm3+ active fibers using methods described in the paper. The additional laser power provides increased coherent lidar capability in range and scanning of large areas but also better system resistance to adverse weather conditions. Wind sensing at ranges beyond 10 km have been achieved and on-going tests of a scanning system dedicated to airport safety is reported.

Airborne lidar mapping of vertical ozone distributions in support of the 1990 Clean Air Act Amendments

NASA Technical Reports Server (NTRS)

Uthe, Edward E.; Nielsen, Norman B.; Livingston, John M.

1992-01-01

The 1990 Clean Air Act Amendments mandated attainment of the ozone standard established by the U.S. Environmental Protection Agency. Improved photochemical models validated by experimental data are needed to develop strategies for reducing near surface ozone concentrations downwind of urban and industrial centers. For more than 10 years, lidar has been used on large aircraft to provide unique information on ozone distributions in the atmosphere. However, compact airborne lidar systems are needed for operation on small aircraft of the type typically used on regional air quality investigations to collect data with which to develop and validate air quality models. Data presented in this paper will consist of a comparison between airborne differential absorption lidar (DIAL) and airborne in-situ ozone measurements. Also discussed are future plans to improve the airborne ultraviolet-DIAL for ozone and other gas observations and addition of a Fourier Transform Infrared (FTIR) emission spectrometer to investigate the effects of other gas species on vertical ozone distribution.

Development of a solid-state sodium Doppler lidar using an all-fiber-coupled injection seeding unit for simultaneous temperature and wind measurements in the mesopause region.

PubMed

Xia, Yuan; Du, LiFang; Cheng, XueWu; Li, FaQuan; Wang, JiHong; Wang, ZeLong; Yang, Yong; Lin, Xin; Xun, YuChang; Gong, ShunSheng; Yang, GuoTao

2017-03-06

A solid-state sodium (Na) Doppler lidar developed at YanQing Station, Beijing, China (40°N, 116°E) aiming to simultaneous wind and temperature measurement of mesopause region was reported. The 589 nm pulse laser was produced by two injection seeded 1064 nm and 1319 nm Nd:YAG pulse lasers using the sum-frequency generation (SFG) technique. A fiber amplifier is implemented to boost the seed power at 1064 nm, enabling a robust, all-fiber-coupled design for seeding laser unit, absolute laser frequency locking, and cyclic three-frequency switching necessary for simultaneous temperature and wind measurements. The all-fiber-coupled injection seeding configuration together with the solid-state Nd:YAG lasers make the Na Doppler lidar more compact and greatly reduce the system maintenance, which is conducive to transportable and unattended operation. A preliminary observational result obtained with this solid-state sodium Doppler lidar was also reported in this paper.

Compact Efficient Lidar Receiver for Measuring Atmospheric Aerosols

NASA Technical Reports Server (NTRS)

Gili, Christopher; De Young, Russell

2006-01-01

A small, light weight, and efficient aerosol lidar receiver was constructed and tested. Weight and space savings were realized by using rigid optic tubes and mounting cubes to package the steering optics and detectors in a compact assembly. The receiver had a 1064nm channel using an APD detector. The 532nm channel was split (90/10) into an analog channel (90%) and a photon counting channel (10%). The efficiency of the 1064nm channel with optical filter was 44.0%. The efficiency of the analog 532nm channel was 61.4% with the optical filter, and the efficiency of the 532nm photon counting channel was 7.6% with the optical filter. The results of the atmospheric tests show that the detectors were able to consistently return accurate results. The lidar receiver was able to detect distinct cloud layers, and the lidar returns also agreed across the different detectors. The use of a light weight fiber-coupled telescope reduced weight and allowed great latitude in detector assembly positioning due to the flexibility enabled by the use of fiber optics. The receiver is now ready to be deployed for aircraft or ground based aerosol lidar measurements.

Novel short-pulse laser diode source for high-resolution 3D flash lidar

NASA Astrophysics Data System (ADS)

Canal, Celine; Laugustin, Arnaud; Kohl, Andreas; Rabot, Olivier

2017-06-01

Imaging based on laser illumination is present in various fields of applications such as medicine, security, defense, civil engineering and in the automotive sector. In this last domain, research and development to bring autonomous vehicles on the roads has been intensified the recent years. Among the various technologies currently studied, automotive lidars are a fast-growing one due to their accuracy to detect a wide range of objects at distances up to a few hundreds of meters in various weather conditions. First commercialized devices for ADAS were laser scanners. Since then, new architectures have recently appeared such as solid-state lidar and flash lidar that offer a higher compactness, robustness and a cost reduction. Flash lidars are based on time-of-flight measurements, with the particularity that they do not require beam scanners because only one short laser pulse with a large divergence is used to enlighten the whole scene. Depth of encountered objects can then be recovered from measurement of echoed light at once, hence enabling real-time 3D mapping of the environment. This paper will bring into the picture a cutting edge laser diode source that can deliver millijoule pulses as short as 12 ns, which makes them highly suitable for integration in flash lidars. They provide a 100-kW peak power highly divergent beam in a footprint of 4x5 cm2 (including both the laser diode and driver) and with a 30-% electrical-to-optical efficiency, making them suitable for integration in environments in which compactness and power consumption are a priority. Their emission in the range of 800-1000 nm is considered to be eye safe when taking into account the high divergence of the output beam. An overview of architecture of these state-of-the-art pulsed laser diode sources will be given together with some solutions for their integration in 3D mapping systems. Future work leads will be discussed for miniaturization of the laser diode and drastic cost reduction.

New Generation Lidar Technology and Applications

NASA Technical Reports Server (NTRS)

Spinhirne, James D.

1999-01-01

Lidar has been a tool for atmospheric research for several decades. Until recently routine operational use of lidar was not known. Problems have involved a lack of appropriate technology rather than a lack of applications. Within the last few years, lidar based on a new generation of solid state lasers and detectors have changed the situation. Operational applications for cloud and aerosol research applications are now well established. In these research applications, the direct height profiling capability of lidar is typically an adjunct to other types of sensing, both passive and active. Compact eye safe lidar with the sensitivity for ground based monitoring of all significant cloud and aerosol structure and the reliability to operate full time for several years is now in routine use. The approach is known as micro pulse lidar (MPL). For MPL the laser pulse repetition rate is in the kilohertz range and the pulse energies are in the micro-Joule range. The low pulse energy permits the systems to be eye safe and reliable with solid state lasers. A number of MPL systems have been deployed since 1992 at atmospheric research sites at a variety of global locations. Accurate monitoring of cloud and aerosol vertical distribution is a critical measurement for atmospheric radiation. An airborne application of lidar cloud and aerosol profiling is retrievals of parameters from combined lidar and passive sensing involving visible, infrared and microwave frequencies. A lidar based on a large pulse, solid state diode pumped ND:YAG laser has been deployed on the NASA ER-2 high altitude research aircraft along with multi-spectral visible/IR and microwave imaging radiometers since 1993. The system has shown high reliability in an extensive series of experimental projects for cloud remote sensing. The retrieval of cirrus radiation parameters is an effective application for combined lidar and passive sensing. An approved NASA mission will soon begin long term lidar observation of atmospheric structure from space. The Geoscience Laser Altimeter System (GLAS) of the Earth Observing System is scheduled for deployment in the 2001 time frame. GLAS is both a cloud and aerosol lidar and a surface altimeter, principally for monitoring of polar ice sheets. The GLAS instrument is based on all solid state lasers operating at 40 Hz and high efficiency, solid state detectors. The design lifetime is three to five years. Data from the GLAS mission is expected to revolutionize some aspects of our understanding of the global distribution of cloud and aerosols for global climate prediction.

Aerosol Measurements by the Globally Distributed Micro Pulse Lidar Network

NASA Technical Reports Server (NTRS)

Spinhirne, James; Welton, Judd; Campbell, James; Berkoff, Tim; Starr, David (Technical Monitor)

2001-01-01

Full time measurements of the vertical distribution of aerosol are now being acquired at a number of globally distributed MP (micro pulse) lidar sites. The MP lidar systems provide full time profiling of all significant cloud and aerosol to the limit of signal attenuation from compact, eye safe instruments. There are currently eight sites in operation and over a dozen planned. At all sited there are also passive aerosol and radiation measurements supporting the lidar data. Four of the installations are at Atmospheric Radiation Measurement program sites. The network operation includes instrument operation and calibration and the processing of aerosol measurements with standard retrievals and data products from the network sites. Data products include optical thickness and extinction cross section profiles. Application of data is to supplement satellite aerosol measurements and to provide a climatology of the height distribution of aerosol. The height distribution of aerosol is important for aerosol transport and the direct scattering and absorption of shortwave radiation in the atmosphere. Current satellite and other data already provide a great amount of information on aerosol distribution, but no passive technique can adequately resolve the height profile of aerosol. The Geoscience Laser Altimeter System (GLAS) is an orbital lidar to be launched in early 2002. GLAS will provide global measurements of the height distribution of aerosol. The MP lidar network will provide ground truth and analysis support for GLAS and other NASA Earth Observing System data. The instruments, sites, calibration procedures and standard data product algorithms for the MPL network will be described.

NASA Goddards LiDAR, Hyperspectral and Thermal (G-LiHT) Airborne Imager

NASA Technical Reports Server (NTRS)

Cook, Bruce D.; Corp, Lawrence A.; Nelson, Ross F.; Middleton, Elizabeth M.; Morton, Douglas C.; McCorkel, Joel T.; Masek, Jeffrey G.; Ranson, Kenneth J.; Ly, Vuong; Montesano, Paul M.

2013-01-01

The combination of LiDAR and optical remotely sensed data provides unique information about ecosystem structure and function. Here, we describe the development, validation and application of a new airborne system that integrates commercial off the shelf LiDAR hyperspectral and thermal components in a compact, lightweight and portable system. Goddard's LiDAR, Hyperspectral and Thermal (G-LiHT) airborne imager is a unique system that permits simultaneous measurements of vegetation structure, foliar spectra and surface temperatures at very high spatial resolution (approximately 1 m) on a wide range of airborne platforms. The complementary nature of LiDAR, optical and thermal data provide an analytical framework for the development of new algorithms to map plant species composition, plant functional types, biodiversity, biomass and carbon stocks, and plant growth. In addition, G-LiHT data enhance our ability to validate data from existing satellite missions and support NASA Earth Science research. G-LiHT's data processing and distribution system is designed to give scientists open access to both low- and high-level data products (http://gliht.gsfc.nasa.gov), which will stimulate the community development of synergistic data fusion algorithms. G-LiHT has been used to collect more than 6,500 km2 of data for NASA-sponsored studies across a broad range of ecoregions in the USA and Mexico. In this paper, we document G-LiHT design considerations, physical specifications, instrument performance and calibration and acquisition parameters. In addition, we describe the data processing system and higher-level data products that are freely distributed under NASA's Data and Information policy.

A Completely Solid-State Tunable Ti:Sapphire Laser System

NASA Technical Reports Server (NTRS)

Guerra, David V.; Coyle, D. Barry; Krebs, Danny J.

1994-01-01

Compact, completely solid-state tunable pulsed laser system passively cooled developed for potential employment in aircraft and sounding-rocket lidar experiments. Ti:sapphire based laser system pumped with frequency-doubled diode-pumped Nd:YAG. Rugged, self-contained system extremely flexible and provides pulsed output at specific frequencies with low input-power requirements. In-situ measurements enables scientists to study upper-atmosphere dynamics. Tuning range easily extended to bands between 650-950 nm in order to study other atmospheric constituents.

Advances in High Energy Solid-State 2-micron Laser Transmitter Development for Ground and Airborne Wind and CO2 Measurements

NASA Technical Reports Server (NTRS)

Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Chen, Songsheng; Kavaya, Michael J.; Trieu, Bo; Bai, Yingxin; Petzar, Paul; Modlin, Edward A.; Koch, Grady;

Progress on High-Energy 2-micron Solid State Laser for NASA Space-Based Wind and Carbon Dioxide Measurements

NASA Technical Reports Server (NTRS)

Singh, Upendra N.

2011-01-01

Sustained research efforts at NASA Langley Research Center during last fifteen years have resulted in significant advancement of a 2-micron diode-pumped, solid-state laser transmitter for wind and carbon dioxide measurements from ground, air and space-borne platforms. Solid-state 2-micron laser is a key subsystem for a coherent Doppler lidar that measures the horizontal and vertical wind velocities with high precision and resolution. The same laser, after a few modifications, can also be used in a Differential Absorption Lidar system for measuring atmospheric CO2 concentration profiles. Researchers at NASA Langley Research Center have developed a compact, flight capable, high energy, injection seeded, 2-micron laser transmitter for ground and airborne wind and carbon dioxide measurements. It is capable of producing 250 mJ at 10 Hz by an oscillator and one amplifier. This compact laser transmitter was integrated into a mobile trailer based coherent Doppler wind and CO2 DIAL system and was deployed during field measurement campaigns. This paper will give an overview of 2-micron solid-state laser technology development and discuss results from recent ground-based field measurements.

Rapid overt airborne reconnaissance (ROAR) for mines and obstacles in very shallow water, surf zone, and beach

NASA Astrophysics Data System (ADS)

Moran, Steven E.; Austin, William L.; Murray, James T.; Roddier, Nicolas A.; Bridges, Robert; Vercillo, Richard; Stettner, Roger; Phillips, Dave; Bisbee, Al; Witherspoon, Ned H.

2003-09-01

Under the Office of Naval Research's Organic Mine Countermeasures Future Naval Capabilities (OMCM FNC) program, Lite Cycles, Inc. is developing an innovative and highly compact airborne active sensor system for mine and obstacle detection in very shallow water (VSW), through the surf-zone (SZ) and onto the beach. The system uses an innovative LCI proprietary integrated scanner, detector, and telescope (ISDT) receiver architecture. The ISD tightly couples all receiver components and LIDAR electronics to achieve the system compaction required for tactical UAVintegration while providing a large aperture. It also includes an advanced compact multifunction laser transmitter; an industry-first high-resolution, compact 3-D camera, a scanning function for wide area search, and temporally displaced multiple looks on the fly over the ocean surface for clutter reduction. Additionally, the laser will provide time-multiplexed multi-color output to perform day/night multispectral imaging for beach surveillance. New processing algorithms for mine detection in the very challenging surf-zone clutter environment are under development, which offer the potential for significant processing gains in comparison to the legacy approaches. This paper reviews the legacy system approaches, describes the mission challenges, and provides an overview of the ROAR system architecture.

Novel pump head design for high energy 1064 nm oscillator amplifier system for lidar applications

NASA Astrophysics Data System (ADS)

Willis, Christina C. C.; Witt, Greg; Martin, Nigel; Albert, Michael; Culpepper, Charles; Burnham, Ralph

2017-02-01

Many scientific endeavors are benefitted by the development of increasingly high energy laser sources for lidar applications. Space-based applications for lidar require compact, efficient and high energy sources, and we have designed a novel gain head that is compatible with these requirements. The gain medium for the novel design consists of a composite Nd:YAG/Sm:YAG slab, wherein the Sm:YAG portion absorbs any parasitic 1064 nm oscillations that might occur in the main pump axis. A pump cavity is built around the slab, consisting of angled gold-coated reflectors which allow for five pump passes from each of the four pumping locations around the slab. Pumping is performed with off-axis diode bars, allowing for highly compact conductively cooled design. Optical and thermal modeling of this design was done to verify and predict its performance. In order to ultimately achieve 50 W average power at a repetition rate of 500 Hz, three heads of this design will be used in a MOPA configuration with two stages of amplification. To demonstrate the pump head we built it into a 1064 nm laser cavity and performed initial amplification experiments. Modeling and design of the system is presented along with the initial oscillator and amplifier results. The greatest pulse energy produced from the seeded q-switched linear oscillator was an output of 25 mJ at 500 Hz. With an input of 25 mJ and two planned stages of amplification, we expect to readily reach 100 mJ or more per pulse.

UAV-borne coherent doppler lidar for marine atmospheric boundary layer observations

NASA Astrophysics Data System (ADS)

Wu, Songhua; Wang, Qichao; Liu, Bingyi; Liu, Jintao; Zhang, Kailin; Song, Xiaoquan

2018-04-01

A compact UAV-borne Coherent Doppler Lidar (UCDL) has been developed at the Ocean University of China for the observation of wind profile and boundary layer structure in Marine Atmospheric Boundary Layer (MABL). The design, specifications and motion-correction methodology of the UCDL are presented. Preliminary results of the first flight campaign in Hailing Island in December 2016 is discussed.

Frequency Agile Tm,Ho:YLF Local Oscillator for a Scanning Doppler wind Lidar in Earth Orbit

NASA Technical Reports Server (NTRS)

Menzies, Robert T.; Hemmati, Hamid; Esproles, Carlos

1997-01-01

A compact cw Tm,Ho:YLF laser with single-mode tunability over +/-4 GHz has been developed into a modular unit containing an isolator and photomixer for offset tuning of the LO from a master oscillator which controls the frequency of a Doppler lidar transmitter. This and an alternative diode laser LO will be described.

Advances in High Energy Solid-State Pulsed 2-Micron Lidar Development for Ground and Airborne Wind, Water Vapor and CO2 Measurements

NASA Technical Reports Server (NTRS)

Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Refaat, Tamer; Kavaya, Michael J.; Remus, Ruben

2015-01-01

NASA Langley Research Center has a long history of developing 2-micron lasers. From fundamental spectroscopy research, theoretical prediction of new materials, laser demonstration and engineering of lidar systems, it has been a very successful program spanning around two decades. Successful development of 2-micron lasers has led to development of a state-of-the-art compact lidar transceiver for a pulsed coherent Doppler lidar system for wind measurement with an unprecedented laser pulse energy of 250 millijoules in a rugged package. This high pulse energy is produced by a Ho:Tm:LuLiF laser with an optical amplifier. While the lidar is meant for use as an airborne instrument, ground-based tests were carried out to characterize performance of the lidar. Atmospheric measurements will be presented, showing the lidar's capability for wind measurement in the atmospheric boundary layer and free troposphere. Lidar wind measurements are compared to a balloon sonde, showing good agreement between the two sensors. Similar architecture has been used to develop a high energy, Ho:Tm:YLF double-pulsed 2-micron Integrated Differential Absorption Lidar (IPDA) instrument based on direct detection technique that provides atmospheric column CO2 measurements. This instrument has been successfully used to measure atmospheric CO2 column density initially from a ground mobile lidar trailer, and then it was integrated on B-200 plane and 20 hours of flight measurement were made from an altitude ranging 1500 meters to 8000 meters. These measurements were compared to in-situ measurements and National Oceanic and Atmospheric Administration (NOAA) airborne flask measurement to derive the dry mixing ratio of the column CO2 by reflecting the signal by various reflecting surfaces such as land, vegetation, ocean surface, snow and sand. The lidar measurements when compared showed a very agreement with in-situ and airborne flask measurement. NASA Langley Research Center is currently developing a triple-pulsed 2-micron Integrated Differential Absorption Lidar (IPDA) instrument for simultaneous measurement of water vapor and carbon-dioxide column density measurement from an air-borne platform. This presentation will give an overview of the 2 decades of 2-micron coherent and direction detection of laser/lidar development at NASA Langley Research Center and will present the ground and airborne wind and column CO2 measurement intercomparison with in-situ, balloon and flask measurements.

Measurements of the Vertical Structure of Aerosols and Clouds Over the Ocean Using Micro-Pulse LIDAR Systems

NASA Technical Reports Server (NTRS)

Welton, Ellsworth J.; Spinhirne, James D.; Campbell, James R.; Berkoff, Timothy A.; Bates, David; Starr, David OC. (Technical Monitor)

2001-01-01

The determination of the vertical distribution of aerosols and clouds over the ocean is needed for accurate retrievals of ocean color from satellites observations. The presence of absorbing aerosol layers, especially at altitudes above the boundary layer, has been shown to influence the calculation of ocean color. Also, satellite data must be correctly screened for the presence of clouds, particularly cirrus, in order to measure ocean color. One instrument capable of providing this information is a lidar, which uses pulses of laser light to profile the vertical distribution of aerosol and cloud layers in the atmosphere. However, lidar systems prior to the 1990s were large, expensive, and not eye-safe which made them unsuitable for cruise deployments. During the 1990s the first small, autonomous, and eye-safe lidar system became available: the micro-pulse lidar, or MPL. The MPL is a compact and eye-safe lidar system capable of determining the range of aerosols and clouds by firing a short pulse of laser light (523 nm) and measuring the time-of-flight from pulse transmission to reception of a returned signal. The returned signal is a function of time, converted into range using the speed of light, and is proportional to the amount of light backscattered by atmospheric molecules (Rayleigh scattering), aerosols, and clouds. The MPL achieves ANSI eye-safe standards by sending laser pulses at low energy (micro-J) and expanding the beam to 20.32 cm in diameter. A fast pulse-repetition-frequency (2500 Hz) is used to achieve a good signal-to-noise, despite the low output energy. The MPL has a small field-of-view (< 100 micro-rad) and signals received with the instrument do not contain multiple scattering effects. The MPL has been used successfully at a number of long-term sites and also in several field experiments around the world.

DC-8 Scanning Lidar Characterization of Aircraft Contrails and Cirrus Clouds

NASA Technical Reports Server (NTRS)

Uthe, Edward E.; Nielsen, Norman B.; Oseberg, Terje E.

1998-01-01

An angular-scanning large-aperture (36 cm) backscatter lidar was developed and deployed on the NASA DC-8 research aircraft as part of the SUCCESS (Subsonic Aircraft: Contrail and Cloud Effects Special Study) program. The lidar viewing direction could be scanned continuously during aircraft flight from vertically upward to forward to vertically downward, or the viewing could be at fixed angles. Real-time pictorial displays generated from the lidar signatures were broadcast on the DC-8 video network and used to locate clouds and contrails above, ahead of, and below the DC-8 to depict their spatial structure and to help select DC-8 altitudes for achieving optimum sampling by onboard in situ sensors. Several lidar receiver systems and real-time data displays were evaluated to help extend in situ data into vertical dimensions and to help establish possible lidar configurations and applications on future missions. Digital lidar signatures were recorded on 8 mm Exabyte tape and generated real-time displays were recorded on 8mm video tape. The digital records were transcribed in a common format to compact disks to facilitate data analysis and delivery to SUCCESS participants. Data selected from the real-time display video recordings were processed for publication-quality displays incorporating several standard lidar data corrections. Data examples are presented that illustrate: (1) correlation with particulate, gas, and radiometric measurements made by onboard sensors, (2) discrimination and identification between contrails observed by onboard sensors, (3) high-altitude (13 km) scattering layer that exhibits greatly enhanced vertical backscatter relative to off-vertical backscatter, and (4) mapping of vertical distributions of individual precipitating ice crystals and their capture by cloud layers. An angular scan plotting program was developed that accounts for DC-8 pitch and velocity.

Lab Demonstration of the Hybrid Doppler Wind Lidar (HDWL) Transceiver

NASA Technical Reports Server (NTRS)

Marx, Catherine T.; Gentry, Bruce; Jordan, Patrick; Dogoda, Peter; Faust, Ed; Kavaya, Michael

2013-01-01

The recommended design approach for the 3D Tropospheric Winds mission is a hybrid Doppler lidar which combines the best elements of both a coherent aerosol Doppler lidar operating at 2 micron and a direct detection molecular Doppler lidar operating at 0.355 micron. In support of the mission, we built a novel, compact, light-weighted multi-field of view transceiver where multiple telescopes are used to cover the required four fields of view. A small mechanism sequentially selects both the "transmit" and "receive" fields of view. The four fields are combined to stimulate both the 0.355 micron receiver and the 2 micron receiver. This version is scaled (0.2 micron diameter aperture) from the space-based version but still demonstrates the feasibility of the hybrid approach. The primary mirrors were conventionally light-weighted and coated with dielectric, high reflectivity coatings with high laser damage thresholds at both 2 micron and 0.355 micron. The mechanical structure and mounts were fabricated from composites to achieve dimensional stability while significantly reducing the mass. In the laboratory, we demonstrated the system level functionality at 0.355 micron and at 2 micron raising the Technology Readiness Level (TRL) from 2 to 4.

Lab Demonstration of the Hybrid Doppler Wind Lidar (HDWL) Transceiver

NASA Technical Reports Server (NTRS)

Marx, Catherine T.; Gentry, Bruce; Jordan, Patrick; Dogoda, Peter; Faust, Ed; Kavaya, Michael

2013-01-01

The recommended design approach for the 3D Tropospheric Winds mission is a hybrid Doppler lidar which combines the best elements of both a coherent aerosol Doppler lidar operating at 2 microns and a direct detection molecular Doppler lidar operating at 0.355 microns. In support of the mission, we built a novel, compact, light-weighted multi-field of view transceiver where multiple telescopes are used to cover the required four fields of view. A small mechanism sequentially selects both the "transmit" and "receive" fields of view. The four fields are combined to stimulate both the 0.355 micron receiver and the 2 micron receiver. This version is scaled (0.2 m diameter aperture) from the space-based version but still demonstrates the feasibility of the hybrid approach. The primary mirrors were conventionally light-weighted and coated with dielectric, high reflectivity coatings with high laser damage thresholds at both 2 microns and 0.355 microns. The mechanical structure and mounts were fabricated from composites to achieve dimensional stability while significantly reducing the mass. In the laboratory, we demonstrated the system level functionality at 0.355 microns and at 2 microns, raising the Technology Readiness Level (TRL) from 2 to 4.

1.5 μm lidar anemometer for true air speed, angle of sideslip, and angle of attack measurements on-board Piaggio P180 aircraft

NASA Astrophysics Data System (ADS)

Augere, B.; Besson, B.; Fleury, D.; Goular, D.; Planchat, C.; Valla, M.

2016-05-01

Lidar (light detection and ranging) is a well-established measurement method for the prediction of atmospheric motions through velocity measurements. Recent advances in 1.5 μm Lidars show that the technology is mature, offers great ease of use, and is reliable and compact. A 1.5 μm airborne Lidar appears to be a good candidate for airborne in-flight measurement systems. It allows measurements remotely, outside aircraft aerodynamic disturbance, and absolute air speed (no need for calibration) with great precision in all aircraft flight domains. In the framework of the EU AIM2 project, the ONERA task has consisted of developing and testing a 1.5 μm anemometer sensor for in-flight airspeed measurements. The objective of this work is to demonstrate that the 1.5 μm Lidar sensor can increase the quality of the data acquisition procedure for aircraft flight test certification. This article presents the 1.5 μm anemometer sensor dedicated to in-flight airspeed measurements and describes the flight tests performed successfully on-board the Piaggio P180 aircraft. Lidar air data have been graphically compared to the air data provided by the aircraft flight test instrumentation (FTI) in the reference frame of the Lidar sensor head. Very good agreement of true air speed (TAS) by a fraction of ms-1, angle of sideslip (AOS), and angle of attack (AOA) by a fraction of degree were observed.

3D flash lidar performance in flight testing on the Morpheus autonomous, rocket-propelled lander to a lunar-like hazard field

NASA Astrophysics Data System (ADS)

Roback, Vincent E.; Amzajerdian, Farzin; Bulyshev, Alexander E.; Brewster, Paul F.; Barnes, Bruce W.

2016-05-01

For the first time, a 3-D imaging Flash Lidar instrument has been used in flight to scan a lunar-like hazard field, build a 3-D Digital Elevation Map (DEM), identify a safe landing site, and, in concert with an experimental Guidance, Navigation, and Control system, help to guide the Morpheus autonomous, rocket-propelled, free-flying lander to that safe site on the hazard field. The flight tests served as the TRL 6 demo of the Autonomous Precision Landing and Hazard Detection and Avoidance Technology (ALHAT) system and included launch from NASA-Kennedy, a lunar-like descent trajectory from an altitude of 250m, and landing on a lunar-like hazard field of rocks, craters, hazardous slopes, and safe sites 400m down-range. The ALHAT project developed a system capable of enabling safe, precise crewed or robotic landings in challenging terrain on planetary bodies under any ambient lighting conditions. The Flash Lidar is a second generation, compact, real-time, air-cooled instrument. Based upon extensive on-ground characterization at flight ranges, the Flash Lidar was shown to be capable of imaging hazards from a slant range of 1 km with an 8 cm range precision and a range accuracy better than 35 cm, both at 1-σ. The Flash Lidar identified landing hazards as small as 30 cm from the maximum slant range which Morpheus could achieve (450 m); however, under certain wind conditions it was susceptible to scintillation arising from air heated by the rocket engine and to pre-triggering on a dust cloud created during launch and transported down-range by wind.

3-D Flash Lidar Performance in Flight Testing on the Morpheus Autonomous, Rocket-Propelled Lander to a Lunar-Like Hazard Field

NASA Technical Reports Server (NTRS)

Roback, Vincent E.; Amzajerdian, Farzin; Bulyshev, Alexander E.; Brewster, Paul F.; Barnes, Bruce W.

2016-01-01

For the first time, a 3-D imaging Flash Lidar instrument has been used in flight to scan a lunar-like hazard field, build a 3-D Digital Elevation Map (DEM), identify a safe landing site, and, in concert with an experimental Guidance, Navigation, and Control (GN&C) system, help to guide the Morpheus autonomous, rocket-propelled, free-flying lander to that safe site on the hazard field. The flight tests served as the TRL 6 demo of the Autonomous Precision Landing and Hazard Detection and Avoidance Technology (ALHAT) system and included launch from NASA-Kennedy, a lunar-like descent trajectory from an altitude of 250m, and landing on a lunar-like hazard field of rocks, craters, hazardous slopes, and safe sites 400m down-range. The ALHAT project developed a system capable of enabling safe, precise crewed or robotic landings in challenging terrain on planetary bodies under any ambient lighting conditions. The Flash Lidar is a second generation, compact, real-time, air-cooled instrument. Based upon extensive on-ground characterization at flight ranges, the Flash Lidar was shown to be capable of imaging hazards from a slant range of 1 km with an 8 cm range precision and a range accuracy better than 35 cm, both at 1-delta. The Flash Lidar identified landing hazards as small as 30 cm from the maximum slant range which Morpheus could achieve (450 m); however, under certain wind conditions it was susceptible to scintillation arising from air heated by the rocket engine and to pre-triggering on a dust cloud created during launch and transported down-range by wind.

2-micron Pulsed Direct Detection IPDA Lidar for Atmospheric CO2 Measurements

NASA Astrophysics Data System (ADS)

Yu, J.; Singh, U.; Petros, M.

2012-12-01

A 2-micron high energy, pulsed Integrated Path Differential Absorption (IPDA) lidar is being developed for atmospheric CO2 measurements. Development of this lidar heavily leverages the 2-micron laser technologies developed in LaRC over the last decade. The high pulse energy, direct detection lidar operating at CO2 2-micron absorption band provides an alternate approach to measure CO2 concentrations with significant advantages. It is expected to provide high-precision measurement capability by unambiguously eliminating contamination from aerosols and clouds that can bias the IPDA measurement. Our objective is to integrate an existing high energy double-pulsed 2-micron laser transmitter with a direct detection receiver and telescope to enable an airborne capability to perform a first proof of principle demonstration of airborne direct detection CO2 measurements. The 2-micron transmitter provides 100mJ at 10Hz with double pulse format specifically designed for DIAL/IPDA instrument. The compact, rugged, highly reliable transceiver is based on unique Ho:Tm:YLF high-energy 2-micron pulsed laser technology. All the optical mounts are custom designed and have space heritage. A 16-inch diameter telescope has been designed and being manufactured for the direct detection lidar. The detector is an InGaAs Positive-Intrinsic-Negative (PIN) photodiode manufactured by Hamamatsu Corporation. The performance of the detector is characterized at various operating temperatures and bias voltages for spectral response, NEP, response time, dynamic range, and linearity. A collinear lidar structure is designed to be integrated to NASA UC12 or B200 research aircrafts. This paper will describe the design of the airborne 2-micron pulsed IPDA lidar system; the lidar operation parameters; the wavelength pair selection; laser transmitter energy, pulse rate, beam divergence, double pulse generation and accurate frequency control; detector characterization; telescope design; lidar structure design; and lidar signal to noise ratio estimation. The first engineering flight is scheduled at the end of next year.

Efficient Third Harmonic Generation for Wind Lidar Applications

NASA Technical Reports Server (NTRS)

Mordaunt, David W.; Cheung, Eric C.; Ho, James G.; Palese, Stephen P.

1998-01-01

The characterization of atmospheric winds on a global basis is a key parameter required for accurate weather prediction. The use of a space based lidar system for remote measurement of wind speed would provide detailed and highly accurate data for future weather prediction models. This paper reports the demonstration of efficient third harmonic conversion of a 1 micrometer laser to provide an ultraviolet (UV) source suitable for a wind lidar system based on atmospheric molecular scattering. Although infrared based lidars using aerosol scattering have been demonstrated to provide accurate wind measurement, a UV based system using molecular or Rayleigh scattering will provide accurate global wind measurements, even in those areas of the atmosphere where the aerosol density is too low to yield good infrared backscatter signals. The overall objective of this work is to demonstrate the maturity of the laser technology and its suitability for a near term flight aboard the space shuttle. The laser source is based on diode-pumped solid-state laser technology which has been extensively demonstrated at TRW in a variety of programs and internal development efforts. The pump laser used for the third harmonic demonstration is a breadboard system, designated the Laser for Risk Reduction Experiments (LARRE), which has been operating regularly for over 5 years. The laser technology has been further refined in an engineering model designated as the Compact Advanced Pulsed Solid-State Laser (CAPSSL), in which the laser head was packaged into an 8 x 8 x 18 inch volume with a weight of approximately 61 pounds. The CAPSSL system is a ruggedized configuration suitable for typical military applications. The LARRE and CAPSSL systems are based on Nd:YAG with an output wavelength of 1064 nm. The current work proves the viability of converting the Nd:YAG fundamental to the third harmonic wavelength at 355 nm for use in a direct detection wind lidar based on atmospheric Rayleigh scattering.

Backscatter-depolarisation lidars on high-altitude research aircraft

NASA Astrophysics Data System (ADS)

Mitev, Valentin; Matthey, Renaud; Makarov, Vladislav

2014-11-01

This article presents an overview of the development and the applications of two compact elastic backscatter depolarisation lidars, installed on-board the high-altitude research aircraft Myasishchev M-55 Geophysica. The installation of the lidars is intended for simultaneous probing of air parcels respectively upward and downward from the aircraft flight altitude to identify the presence of clouds (or aerosol )above and below the aircraft and to collocate them with in situ instruments. The lidar configuration and the procedure for its on-ground validation is outlined. Example of airborne measurements include polar stratospheric clouds, both synoptical and in lee-waves, ultra-thin cirrus clouds around the tropical tropopause and observation of aerosol layers emerging from the top of deep tropical convection.

A Compact Frequency Agile Mid-Infrared Airborne Lidar

DTIC Science & Technology

2006-10-01

et al. demonstrated a PPLN OPO pumped by a tunable ytterbium - doped fiber laser [11]. The system delivers a tunable mid-infrared output with a peak...shared component with it. OPO Resonator Mirrors Pump Laser Signal => , =0 ..rt.«^.._S„.5lfc>..J Idler Nonlinear Optical Crystal (a) Pump...signal- to-noise ratio (Figure 31). Tuning was accomplished by rotating the crystal. The theoretical analysis of up-conversion in LiNbC>3 crystal

Measurement of the Vertical Distribution of Aerosol by Globally Distributed MP Lidar Network Sites

NASA Technical Reports Server (NTRS)

Spinhirne, James; Welton, Judd; Campbell, James; Starr, David OC. (Technical Monitor)

2001-01-01

The global distribution of aerosol has an important influence on climate through the scattering and absorption of shortwave radiation and through modification of cloud optical properties. Current satellite and other data already provide a great amount of information on aerosol distribution. However there are critical parameters that can only be obtained by active optical profiling. For aerosol, no passive technique can adequately resolve the height profile of aerosol. The aerosol height distribution is required for any model for aerosol transport and the height resolved radiative heating/cooling effect of aerosol. The Geoscience Laser Altimeter System (GLAS) is an orbital lidar to be launched by 2002. GLAS will provide global measurements of the height distribution of aerosol. The sampling will be limited by nadir only coverage. There is a need for local sites to address sampling, and accuracy factors. Full time measurements of the vertical distribution of aerosol are now being acquired at a number of globally distributed MP (micro pulse) lidar sites. The MP lidar systems provide profiling of all significant cloud and aerosol to the limit of signal attenuation from compact, eye safe instruments. There are currently six sites in operation and over a dozen planned. At all sites there are a complement of passive aerosol and radiation measurements supporting the lidar data. Four of the installations are at Atmospheric Radiation Measurement program sites. The aerosol measurements, retrievals and data products from the network sites will be discussed. The current and planned application of data to supplement satellite aerosol measurements is covered.

Validation of Long Range Wind Lidar for Atmospheric Dynamics Studies during inter comparison campaign

NASA Astrophysics Data System (ADS)

Boquet, M.; Cariou, J. P.; Lolli, S.; Sauvage, L.; Parmentier, R.

2009-09-01

To fully understand atmospheric dynamics, climate studies, energy transfer and weather prediction, the wind field is one of the most important atmospheric state variables. Studies indicate that a global determination of the tropospheric wind field to an accuracy of 0.5 m/s is critical for improved numerical weather forecasting. LEOSPHERE recently developed a long range compact, eye safe and transportable wind Lidar capable to fully determine locally the wind field in real time in the planetary boundary layer (PBL). The WLS70 is a new generation wind Lidar developed for meteorological applications. The Lidar is derived from the commercial Windcube™ widely used by the wind industry and has been modified increasing the range up to 2 km. In this paper are presented results of the inter comparison measurement campaigns EUCAARI, LUAMI and WAVES in which the WLS70 participated together with both up-to-date active and passive ground-based remote-sensing systems for providing high-quality meteorological parameters reference or ground-truth e.g. to satellite sensors. In May 2008, the first WLS70 prototype started retrieving vertical wind speed profiles during the EUCAARI campaign at Cabauw, the Netherlands. First results were very promising with vertical profiles up to 2km showing high frequency updrafts and downdrafts in the boundary layer. From November 2008 to January 2009, a WLS70 was deployed in Germany, together with an EZ Lidar™ ALS450, in the frame of the Lindenberg Upper Air Methods Intercomparison (LUAMI) campaign. During 62 days, the WLS70 Lidar retrieved 24/24 hours vertical profiles of the 3 wind components, putting in evidence wind shears and veers, as well as gusts and high frequency convective effects with the raise of the mixing layer or with incoming rain fronts. In-cloud and multilayer measurements are also available allowing a large range of additional investigations such as cloud-aerosol interactions or cloud droplet activation. From March to May 2009, LEOSPHERE deployed a WLS70 prototype unit at the Howard University Research Campus in Beltsville, Maryland, for the Water Vapor Validation Experiments (WAVES) from the initiative of the NOAA. The presence of numerous wind profilers, lidars and radio soundings was a perfect opportunity to test and improve this new compact and autonomous long range wind Lidar. The WLS70 showed Low Level Jet phenomena which have strong impact on air quality. During these intensive inter comparison campaigns the WLS70 Wind Lidar was validated against Lidars, Radars, Sodars and anemometers. The results show mostly a very good agreement between the instruments. Moreover, the measurements put in evidence both horizontal and vertical wind speed and wind direction vertical profiles and atmosphere structure (PBL height , clouds base) derived from Lidar data with good time resolution (10s/profile), good range resolution (50m from 100m to 2000m), and good velocity resolution (0.2m/s). Enhanced measurement range is now expected through new optical device.

Remote sensing of atmospheric NO2 by employing the continuous-wave differential absorption lidar technique.

PubMed

Mei, Liang; Guan, Peng; Kong, Zheng

2017-10-02

Differential absorption lidar (DIAL) technique employed for remote sensing has been so far based on the sophisticated narrow-band pulsed laser sources, which require intensive maintenance during operation. In this work, a continuous-wave (CW) NO 2 DIAL system based on the Scheimpflug principle has been developed by employing a compact high-power CW multimode 450 nm laser diode as the light source. Laser emissions at the on-line and off-line wavelengths of the NO 2 absorption spectrum are implemented by tuning the injection current of the laser diode. Lidar signals are detected by a 45° tilted area CCD image sensor satisfying the Scheimpflug principle. Range-resolved NO 2 concentrations on a near-horizontal path are obtained by the NO 2 DIAL system in the range of 0.3-3 km and show good agreement with those measured by a conventional air pollution monitoring station. A detection sensitivity of ± 0.9 ppbv at 95% confidence level in the region of 0.3-1 km is achieved with 15-minute averaging and 700 m range resolution during hours of darkness, which allows accurate concentration measurement of ambient NO 2 . The low-cost and robust DIAL system demonstrated in this work opens up many possibilities for field NO 2 remote sensing applications.

Development of a UAV-based Global Ozone Lidar Demonstrator (GOLD)

NASA Astrophysics Data System (ADS)

Browell, E. V.; Deyoung, R. J.; Hair, J. W.; Ismail, S.; McGee, T.; Hardesty, R. M.; Brewer, W. A.; McDermid, I. S.

2006-12-01

Global ozone measurements are needed across the troposphere with high vertical resolution to enable comprehensive studies of continental and intercontinental atmospheric chemistry and dynamics, which are affected by diverse natural and human-induced processes. The development of a unattended aerial vehicle (UAV) based Global Ozone Lidar Demonstrator (GOLD) is an important step in enabling a space-based ozone and aerosol lidar and for conducting unique UAV-based large-scale atmospheric investigations. The GOLD system will incorporate the most advanced technology developed under the NASA Laser Risk Reduction Program (LRRP) and the Small Business Innovative Research (SBIR) program to produce a compact, autonomously operating ozone and aerosol Differential Absorption Lidar (DIAL) system for a UAV platform. This system will leverage advanced Nd:YAG and optical parametric oscillator (OPO) laser technologies being developed by ITT Industries under the LRRP and the autonomously operating ozone DIAL system being developed by Science and Engineering Services Inc. (SESI) under an SBIR Phase-3 contract. Laser components from ITT will be integrated into the SESI DIAL system, and the resulting GOLD system will be flight tested on a NASA UAV. The development of the GOLD system was initiated as part of the NASA Instrument Incubator Program in December 2005, and great progress has been made towards completing major GOLD subsystems. ITT has begun construction of the high-power Nd:YAG pump laser and the ultraviolet OPO for generating the ozone DIAL wavelengths of 290 and 300 nm and the aerosol visible wavelength at 532 nm. SESI is completing the Phase-3 SBIR contract for the delivery and demonstration of the ozone DIAL receiver and data system, and NOAA is completing detector evaluations for use in the GOLD system. Welch Mechanical is examining system designs for integrating GOLD into the external pod that will be hung under the new IKANA (Predator-B) UAV that NASA Dryden is acquiring. Details of the GOLD system design and development will be presented in this paper, and science applications for a UAV-based and space-based ozone lidar will be discussed.

New capability for ozone dial profiling measurements in the troposphere and lower stratosphere from aircraft

NASA Astrophysics Data System (ADS)

Hair, Johnathan; Hostetler, Chris; Cook, Anthony; Harper, David; Notari, Anthony; Fenn, Marta; Newchurch, Mike; Wang, Lihua; Kuang, Shi; Knepp, Travis; Burton, Sharon; Ferrare, Richard; Butler, Carolyn; Collins, Jim; Nehrir, Amin

2018-04-01

Recently, we successfully demonstrated a new compact and robust ozone DIAL lidar for smaller aircraft such as the NASA B200 and the ER-2 high-altitude aircraft. This is the first NASA airborne lidar to incorporate advanced solid-state lasers to produce the required power at the required ultraviolet wavelengths, and is compact and robust enough to operate nearly autonomously on the high-altitude ER-2 aircraft. This technology development resulted in the first new NASA airborne ozone DIAL instrument in more than 15 years. The combined ozone, aerosol, and clouds measurements provide valuable information on the chemistry, radiation, and dynamics of the atmosphere. In particular, from the ER-2 it offers a unique capability to study the upper troposphere and lower stratosphere.

Atmospheric aerosol and gas sensing using Scheimpflug lidar

NASA Astrophysics Data System (ADS)

Mei, Liang; Brydegaard, Mikkel

2015-04-01

This work presents a new lidar technique for atmospheric remote sensing based on Scheimpflug principle, which describes the relationship between nonparallel image- and object-planes[1]. When a laser beam is transmitted into the atmosphere, the implication is that the backscattering echo of the entire illuminated probe volume can be in focus simultaneously without diminishing the aperture. The range-resolved backscattering echo can be retrieved by using a tilted line scan or two-dimensional CCD/CMOS camera. Rather than employing nanosecond-pulsed lasers, cascade detectors, and MHz signal sampling, all of high cost and complexity, we have developed a robust and inexpensive atmospheric lidar system based on compact laser diodes and array detectors. We present initial applications of the Scheimpflug lidar for atmospheric aerosol monitoring in bright sunlight, with a 3 W, 808 nm CW laser diode. Kilohertz sampling rates are also achieved with applications for wind speed and entomology [2]. Further, a proof-of-principle demonstration of differential absorption lidar (DIAL) based on the Scheimpflug lidar technique is presented [3]. By utilizing a 30 mW narrow band CW laser diode emitting at around 760 nm, the detailed shape of an oxygen absorption line can be resolved remotely with an integration time of 6 s and measurement cycle of 1 minute during night time. The promising results demonstrated in this work show potential for the Scheimpflug lidar technique for remote atmospheric aerosol and gas sensing, and renews hope for robust and realistic instrumentation for atmospheric lidar sensing. [1] F. Blais, "Review of 20 years of range sensor development," Journal of Electronic Imaging, vol. 13, pp. 231-243, Jan 2004. [2] M. Brydegaard, A. Gebru, and S. Svanberg, "Super resolution laser radar with blinking atmospheric particles - application to interacting flying insects " Progress In Electromagnetics Research, vol. 147, pp. 141-151, 2014. [3] L. Mei and M. Brydegaard, "Contineous-wave differential absorption lidar," Submitted to Laser and Photonics Reviews, 2014.

Demonstration of coherent Doppler lidar for navigation in GPS-denied environments

NASA Astrophysics Data System (ADS)

Amzajerdian, Farzin; Hines, Glenn D.; Pierrottet, Diego F.; Barnes, Bruce W.; Petway, Larry B.; Carson, John M.

2017-05-01

A coherent Doppler lidar has been developed to address NASA's need for a high-performance, compact, and cost-effective velocity and altitude sensor onboard its landing vehicles. Future robotic and manned missions to solar system bodies require precise ground-relative velocity vector and altitude data to execute complex descent maneuvers and safe, soft landing at a pre-designated site. This lidar sensor, referred to as a Navigation Doppler Lidar (NDL), meets the required performance of the landing missions while complying with vehicle size, mass, and power constraints. Operating from up to four kilometers altitude, the NDL obtains velocity and range precision measurements reaching 2 cm/sec and 2 meters, respectively, dominated by the vehicle motion. Terrestrial aerial vehicles will also benefit from NDL data products as enhancement or replacement to GPS systems when GPS is unavailable or redundancy is needed. The NDL offers a viable option to aircraft navigation in areas where the GPS signal can be blocked or jammed by intentional or unintentional interference. The NDL transmits three laser beams at different pointing angles toward the ground to measure range and velocity along each beam using a frequency modulated continuous wave (FMCW) technique. The three line-of-sight measurements are then combined in order to determine the three components of the vehicle velocity vector and its altitude relative to the ground. This paper describes the performance and capabilities that the NDL demonstrated through extensive ground tests, helicopter flight tests, and onboard an autonomous rocket-powered test vehicle while operating in closedloop with a guidance, navigation, and control (GN and C) system.

Ultraviolet Rayleigh-Mie lidar for daytime-temperature profiling of the troposphere.

PubMed

Hua, Dengxin; Uchida, Masaru; Kobayashi, Takao

2005-03-01

A UV Rayleigh-Mie scattering lidar has been developed for daytime measurement of temperature and aerosol optical properties in the troposphere. The transmitter is a narrowband, injection-seeded, pulsed, third-harmonic Nd:YAG laser at an eye-safe wavelength of 355 nm. Two Fabry-Perot etalons (FPEs) with a dual-pass optical layout filter the molecular Rayleigh scattering components spectrally for retrieval of the temperature and provide a high rejection rate for aerosol Mie scattering in excess of 43 dB. The Mie signal is filtered with a third FPE filter for direct profiling of aerosol optical properties. The Mie scattering component in the Rayleigh signals, which will have influence on temperature measurements, is corrected by using a measure of aerosol scattering because of the relative insufficiency of Mie rejection of Rayleigh filters in the presence of dense aerosols or clouds, and the Mie rejection capability of system is thus improved. A narrowband interference filter is incorporated with the FPEs to block solar radiation. Also, the small field of view (0.1 mrad) of the receiver and the UV wavelength used enhance the ability of the lidar to suppress the solar background signal in daytime measurement. The system is relatively compact, with a power-aperture product of 0.18 W m(-2), and has a high sensitivity to temperature change (0.62%/K). Lidar measurements taken under different weather conditions (winter and summer) are demonstrated. Good agreement between the lidar and the radiosonde measurements was obtained in terms of lapse rates and inversions. Statistical temperature errors of less than 1 K up to a height of 2 km are obtainable, with an averaging time of approximately 12 min for daytime measurements.

Experimental tests and radiometric calculations for the feasibility of fluorescence LIDAR-based discrimination of oil spills from UAV

NASA Astrophysics Data System (ADS)

Raimondi, Valentina; Palombi, Lorenzo; Lognoli, David; Masini, Andrea; Simeone, Emilio

2017-09-01

This paper presents experimental tests and radiometric calculations for the feasibility of an ultra-compact fluorescence LIDAR from an Unmanned Air Vehicle (UAV) for the characterisation of oil spills in natural waters. The first step of this study was to define the experimental conditions for a LIDAR and its budget constraints on the basis of the specifications of small UAVs already available on the market. The second step consisted of a set of fluorescence LIDAR measurements on oil spills in the laboratory in order to propose a simplified discrimination method and to calculate the oil fluorescence conversion efficiency. Lastly, the main technical specifications of the payload were defined and radiometric calculations carried out to evaluate the performances of both the payload and the proposed discrimination method.

Out of the Lab...Into the Real World

NASA Technical Reports Server (NTRS)

1999-01-01

Big Sky Laser Technologies of Bozeman, MT is a developer of compact, ruggedized commercial and developmental laser systems, including small medical lasers and Lidars used in NASA tracking applications. Company engineers developing new laser products determined that NASA technology for detection and control of prelasing in a Q-switched laser would be of value to them in at least two of their product lines. Big Sky Laser's CFR-800 unit is based on NASA technology to which they obtained a non-exclusive patent.

Integrated four-channel all-fiber up-conversion single-photon-detector with adjustable efficiency and dark count.

PubMed

Zheng, Ming-Yang; Shentu, Guo-Liang; Ma, Fei; Zhou, Fei; Zhang, Hai-Ting; Dai, Yun-Qi; Xie, Xiuping; Zhang, Qiang; Pan, Jian-Wei

2016-09-01

Up-conversion single photon detector (UCSPD) has been widely used in many research fields including quantum key distribution, lidar, optical time domain reflectrometry, and deep space communication. For the first time in laboratory, we have developed an integrated four-channel all-fiber UCSPD which can work in both free-running and gate modes. This compact module can satisfy different experimental demands with adjustable detection efficiency and dark count. We have characterized the key parameters of the UCSPD system.

Validation campaigns of a coherent Doppler Wind Lidar for PBL Continuous Profiling

NASA Astrophysics Data System (ADS)

Sauvage, Laurent; Cariou, Jean-Pierre; Boquet, Matthieu; Parmentier, Remy

2010-05-01

To fully understand atmospheric dynamics, climate studies, energy transfer and weather prediction, the wind field is one of the most important atmospheric state variables. Studies indicate that a global determination of the tropospheric wind field to an accuracy of 0.5 m/s is critical for improved numerical weather forecasting. LEOSPHERE recently developed a long range compact, eye safe and transportable wind Lidar capable to fully determine locally the wind field in real time in the planetary boundary layer (PBL). The WLS70 is a new generation wind Lidar developed for meteorological applications. The Lidar is derived from the commercial Windcube™ widely used by the wind industry and has been modified increasing the range up to 2 km. In this paper are presented results of the inter comparison measurement campaigns EUCAARI, LUAMI and WAVES in which the WLS70 participated together with both up-to-date active and passive ground-based remote-sensing systems for providing high-quality meteorological parameters reference or ground-truth e.g. to satellite sensors. In May 2008, the first WLS70 prototype started retrieving vertical wind speed profiles during the EUCAARI campaign at Cabauw, the Netherlands. First results were very promising with vertical profiles up to 2km showing high frequency updrafts and downdrafts in the boundary layer. From November 2008 to January 2009, a WLS70 was deployed in Germany, together with an EZ Lidar™ ALS450, in the frame of the Lindenberg Upper Air Methods Intercomparison (LUAMI) campaign. During 62 days, the WLS70 Lidar retrieved 24/24 hours vertical profiles of the 3 wind components, putting in evidence wind shears and veers, as well as gusts and high frequency convective effects with the raise of the mixing layer or with incoming rain fronts. In-cloud and multilayer measurements are also available allowing a large range of additional investigations such as cloud-aerosol interactions or cloud droplet activation. From March to May 2009, LEOSPHERE deployed a WLS70 prototype unit at the Howard University Research Campus in Beltsville, Maryland, for the Water Vapor Validation Experiments (WAVES) from the initiative of the NOAA. The presence of numerous wind profilers, lidars and radio soundings was a perfect opportunity to test and improve this new compact and autonomous long range wind Lidar. The WLS70 showed Low Level Jet phenomena which have strong impact on air quality. In July 2009, the WLS70 took its definitive configuration with a new optical device installed on it allowing enhanced measurement range. New measurements were done at PNNL in Richland, Washington, and NASA Langley in Hampton, Virginia. These results are now processed and will bring a further proof on reliability and accuracy. During these intensive inter comparison campaigns the WLS70 Wind Lidar was validated against Lidars, Radars, Sodars and anemometers. The results show mostly a very good agreement between the instruments. Moreover, the measurements put in evidence both horizontal and vertical wind speed and wind direction vertical profiles and atmosphere structure (PBL height , clouds base) derived from Lidar data with good time resolution (10s/profile), good range resolution (50m from 100m to 2000m), and good velocity accuracy.

Iodine-filter-based mobile Doppler lidar to make continuous and full-azimuth-scanned wind measurements: data acquisition and analysis system, data retrieval methods, and error analysis.

PubMed

Wang, Zhangjun; Liu, Zhishen; Liu, Liping; Wu, Songhua; Liu, Bingyi; Li, Zhigang; Chu, Xinzhao

2010-12-20

An incoherent Doppler wind lidar based on iodine edge filters has been developed at the Ocean University of China for remote measurements of atmospheric wind fields. The lidar is compact enough to fit in a minivan for mobile deployment. With its sophisticated and user-friendly data acquisition and analysis system (DAAS), this lidar has made a variety of line-of-sight (LOS) wind measurements in different operational modes. Through carefully developed data retrieval procedures, various wind products are provided by the lidar, including wind profile, LOS wind velocities in plan position indicator (PPI) and range height indicator (RHI) modes, and sea surface wind. Data are processed and displayed in real time, and continuous wind measurements have been demonstrated for as many as 16 days. Full-azimuth-scanned wind measurements in PPI mode and full-elevation-scanned wind measurements in RHI mode have been achieved with this lidar. The detection range of LOS wind velocity PPI and RHI reaches 8-10 km at night and 6-8 km during daytime with range resolution of 10 m and temporal resolution of 3 min. In this paper, we introduce the DAAS architecture and describe the data retrieval methods for various operation modes. We present the measurement procedures and results of LOS wind velocities in PPI and RHI scans along with wind profiles obtained by Doppler beam swing. The sea surface wind measured for the sailing competition during the 2008 Beijing Olympics is also presented. The precision and accuracy of wind measurements are estimated through analysis of the random errors associated with photon noise and the systematic errors introduced by the assumptions made in data retrieval. The three assumptions of horizontal homogeneity of atmosphere, close-to-zero vertical wind, and uniform sensitivity are made in order to experimentally determine the zero wind ratio and the measurement sensitivity, which are important factors in LOS wind retrieval. Deviations may occur under certain meteorological conditions, leading to bias in these situations. Based on the error analyses and measurement results, we point out the application ranges of this Doppler lidar and propose several paths for future improvement.

Full-Time, Eye-Safe Cloud and Aerosol Lidar Observation at Atmospheric Radiation Measurement Program Sites: Instruments and Data Analysis

NASA Technical Reports Server (NTRS)

Campbell, James R.; Hlavka, Dennis L.; Welton, Ellsworth J.; Flynn, Connor J.; Turner, David D.; Spinhirne, James D.; Scott, V. Stanley, III; Hwang, I. H.; Einaudi, Franco (Technical Monitor)

2001-01-01

Atmospheric radiative forcing, surface radiation budget, and top of the atmosphere radiance interpretation involves a knowledge of the vertical height structure of overlying cloud and aerosol layers. During the last decade, the U.S. Department of Energy through I the Atmospheric Radiation Measurement (ARM) program has constructed four long- term atmospheric observing sites in strategic climate regimes (north central Oklahoma, In Barrow. Alaska, and Nauru and Manus Islands in the tropical western Pacific). Micro Pulse Lidar (MPL) systems provide continuous, autonomous observation of all significant atmospheric cloud and aerosol at each of the central ARM facilities. Systems are compact and transmitted pulses are eye-safe. Eye-safety is achieved by expanding relatively low-powered outgoing Pulse energy through a shared, coaxial transmit/receive telescope. ARM NIPL system specifications, and specific unit optical designs are discussed. Data normalization and calibration techniques are presented. A multiple cloud boundary detection algorithm is also described. These techniques in tandem represent an operational value added processing package used to produce normalized data products for Cloud and aerosol research and the historical ARM data archive.

Spectrally Tailored Pulsed Thulium Fiber Laser System for Broadband Lidar CO2 Sensing

NASA Technical Reports Server (NTRS)

Heaps, William S.; Georgieva, Elena M.; McComb, Timothy S.; Cheung, Eric C.; Hassell, Frank R.; Baldauf, Brian K.

2011-01-01

Thulium doped pulsed fiber lasers are capable of meeting the spectral, temporal, efficiency, size and weight demands of defense and civil applications for pulsed lasers in the eye-safe spectral regime due to inherent mechanical stability, compact "all-fiber" master oscillator power amplifier (MOPA) architectures, high beam quality and efficiency. Thulium fiber's longer operating wavelength allows use of larger fiber cores without compromising beam quality, increasing potential single aperture pulse energies. Applications of these lasers include eye-safe laser ranging, frequency conversion to longer or shorter wavelengths for IR countermeasures and sensing applications with otherwise tough to achieve wavelengths and detection of atmospheric species including CO2 and water vapor. Performance of a portable thulium fiber laser system developed for CO2 sensing via a broadband lidar technique with an etalon based sensor will be discussed. The fielded laser operates with approximately 280 J pulse energy in 90-150ns pulses over a tunable 110nm spectral range and has a uniquely tailored broadband spectral output allowing the sensing of multiple CO2 lines simultaneously, simplifying future potentially space based CO2 sensing instruments by reducing the number and complexity of lasers required to carry out high precision sensing missions. Power scaling and future "all fiber" system configurations for a number of ranging, sensing, countermeasures and other yet to be defined applications by use of flexible spectral and temporal performance master oscillators will be discussed. The compact, low mass, robust, efficient and readily power scalable nature of "all-fiber" thulium lasers makes them ideal candidates for use in future space based sensing applications.

Micro pulse laser radar

NASA Technical Reports Server (NTRS)

Spinhirne, James D. (Inventor)

1993-01-01

An eye safe, compact, solid state lidar for profiling atmospheric cloud and aerosol scattering is disclosed. The transmitter of the micro pulse lidar is a diode pumped micro-J pulse energy, high repetition rate Nd:YLF laser. Eye safety is obtained through beam expansion. The receiver employs a photon counting solid state Geiger mode avalanche photodiode detector. Data acquisition is by a single card multichannel scaler. Daytime background induced quantum noise is controlled by a narrow receiver field-of-view and a narrow bandwidth temperature controlled interference filter. Dynamic range of the signal is limited to optical geometric signal compression. Signal simulations and initial atmospheric measurements indicate that micropulse lider systems are capable of detecting and profiling all significant cloud and aerosol scattering through the troposphere and into the stratosphere. The intended applications are scientific studies and environmental monitoring which require full time, unattended measurements of the cloud and aerosol height structure.

The NASA Micro-Pulse Lidar Network (MPLNET): Co-location of Lidars with AERONET

NASA Technical Reports Server (NTRS)

Welton, Ellsworth J.; Campbell, James R.; Berkoff, Timothy A.; Spinhirne, James D.; Holben, Brent; Tsay, Si-Chee

2004-01-01

We present the formation of a global-ground based eye-safe lidar network, the NASA Micro-Pulse Lidar Network (MPLNET). The aim of MPLNET is to acquire long-term observations of aerosol and cloud vertical profiles at unique geographic sites within the NASA Aerosol Robotic Network (AERONET). Network growth follows a federated approach, pioneered by AERONET, wherein independent research groups may join MPLNET with their own instrument and site. MPLNET utilizes standard instrumentation and data processing algorithms for efficient network operations and direct comparison of data between each site. The micro-pulse lidar is eye-safe, compact, and commercially available, and most easily allows growth of the network without sacrificing standardized instrumentation gods. Red-time data products (next-day) are available, and include Level 1 daily lidar signal images from the surface to -2Okm, and Level 1.5 aerosol extinction provides at times co-incident with AERONET observations. Testing of our quality assured aerosol extinction products, Level 2, is near completion and data will soon be available. Level 3 products, continuous daylight aerosol extinction profiles, are under development and testing has begun. An overview of h4PL" will be presented. Successful methods of merging standardized lidar operations with AERONET will also be discussed, with the first 4 years of MPLNET results serving as an example.

Micro-pulse upconversion Doppler lidar for wind and visibility detection in the atmospheric boundary layer.

PubMed

Xia, Haiyun; Shangguan, Mingjia; Wang, Chong; Shentu, Guoliang; Qiu, Jiawei; Zhang, Qiang; Dou, Xiankang; Pan, Jianwei

2016-11-15

For the first time, to the best of our knowledge, a compact, eye-safe, and versatile direct detection Doppler lidar is developed using an upconversion single-photon detection method at 1.5 μm. An all-fiber and polarization maintaining architecture is realized to guarantee the high optical coupling efficiency and the robust stability. Using integrated-optic components, the conservation of etendue of the optical receiver is achieved by manufacturing a fiber-coupled periodically poled lithium niobate waveguide and an all-fiber Fabry-Perot interferometer (FPI). The double-edge technique is implemented by using a convert single-channel FPI and a single upconversion detector, incorporating a time-division multiplexing method. The backscatter photons at 1548.1 nm are converted into 863 nm via mixing with a pump laser at 1950 nm. The relative error of the system is less than 0.1% over nine weeks. In experiments, atmospheric wind and visibility over 48 h are detected in the boundary layer. The lidar shows good agreement with the ultrasonic wind sensor, with a standard deviation of 1.04 m/s in speed and 12.3° in direction.

Stabilized diode seed laser for flight and space-based remote lidar sensing applications

NASA Astrophysics Data System (ADS)

McNeil, Shirley; Pandit, Pushkar; Battle, Philip; Rudd, Joe; Hovis, Floyd

2017-08-01

AdvR, through support of the NASA SBIR program, has developed fiber-based components and sub-systems that are routinely used on NASA's airborne missions, and is now developing an environmentally hardened, diode-based, locked wavelength, seed laser for future space-based high spectral resolution lidar applications. The seed laser source utilizes a fiber-coupled diode laser, a fiber-coupled, calibrated iodine reference module to provide an absolute wavelength reference, and an integrated, dual-element, nonlinear optical waveguide component for second harmonic generation, spectral formatting and wavelength locking. The diode laser operates over a range close to 1064.5 nm, provides for stabilization of the seed to the desired iodine transition and allows for a highly-efficient, fully-integrated seed source that is well-suited for use in airborne and space-based environments. A summary of component level environmental testing and spectral purity measurements with a seeded Nd:YAG laser will be presented. A direct-diode, wavelength-locked seed laser will reduce the overall size weight and power (SWaP) requirements of the laser transmitter, thus directly addressing the need for developing compact, efficient, lidar component technologies for use in airborne and space-based environments.

Laser remote sensing of an algal bloom in a freshwater reservoir

NASA Astrophysics Data System (ADS)

Grishin, M. Ya; Lednev, V. N.; Pershin, S. M.; Bunkin, A. F.; Kobylyanskiy, V. V.; Ermakov, S. A.; Kapustin, I. A.; Molkov, A. A.

2016-12-01

Laser remote sensing of an algal bloom in a freshwater reservoir on the Volga River in central Russia was carried out. The compact Raman lidar was installed on a small ship to probe the properties of the surface water layer in different typical regions of Gorky Water Reservoir. Elastic and Raman scattering as well as chlorophyll fluorescence were quantified, mapped and compared with data acquired by a commercial salinity, temperature and depth probe (STD probe) equipped with a blue-green algae sensor. Good correlation between lidar and STD measurements was established.

Development of Advanced Seed Laser Modules for Lidar and Spectroscopy Applications

NASA Technical Reports Server (NTRS)

Prasad, Narasimha S.; Rosiewicz, Alex; Coleman, Steven M.

2013-01-01

We report on recent progress made in the development of highly compact, single mode, distributed feedback laser (DFB) seed laser modules for lidar and spectroscopy applications from space based platforms. One of the intended application of this technology is in the NASA's Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission. The DFB laser modules operating at 1571 nm and 1262 nm have advanced current and temperature drivers built into them. A combination of temperature and current tuning allows coarse and fine adjustment of the diode wavelengths.

Optical design and development of near-range compact lidar

NASA Astrophysics Data System (ADS)

Shiina, Tatsuo

2011-12-01

There are large demands to monitor the atmosphere in the closed space (hall, factory and so on), to check vegetation remotely and to detect hazardous gases such as explosive gas and bio terror from explosion-proof distance. On the contrary, traditional lidars have blind area, it is hard to monitor the atmosphere and the gas in the near range. In this study, optical designs and concrete developments for the atmosphere monitoring and the certain gas detection in near range were accomplished. Unique optical designs are introduced and their practical setups are explained.

Validation Campaigns of a new 1.5μm Doppler Wind Lidar for PBL Continuous Profiling

NASA Astrophysics Data System (ADS)

Sauvage, Laurent; Boquet, Matthieu; Cariou, Jean-Pierre; Lolli, Simone

2010-05-01

To fully understand atmospheric dynamics, climate studies, energy transfer and weather prediction, the wind field is one of the most important atmospheric state variables. Studies indicate that a global determination of the tropospheric wind field to an accuracy of 0.5 m/s is critical for improved numerical weather forecasting. LEOSPHERE recently developed a long range compact, eye safe and transportable wind Lidar capable to fully determine locally the wind field in real time in the planetary boundary layer (PBL). The WLS70 is a new generation wind Lidar developed for meteorological applications. The Lidar is derived from the commercial Windcube™ widely used by the wind industry and has been modified increasing the range up to 2 km. In this paper are presented results of the inter comparison measurement campaigns EUCAARI, LUAMI and WAVES in which the WLS70 participated together with both up-to-date active and passive ground-based remote-sensing systems for providing high-quality meteorological parameters reference or ground-truth e.g. to satellite sensors. In May 2008, the first WLS70 prototype started retrieving vertical wind speed profiles during the EUCAARI campaign at Cabauw, the Netherlands. First results were very promising with vertical profiles up to 2km showing high frequency updrafts and downdrafts in the boundary layer. From November 2008 to January 2009, a WLS70 was deployed in Germany, together with an EZ Lidar™ ALS450, in the frame of the Lindenberg Upper Air Methods Intercomparison (LUAMI) campaign. During 62 days, the WLS70 Lidar retrieved 24/24 hours vertical profiles of the 3 wind components, putting in evidence wind shears and veers, as well as gusts and high frequency convective effects with the raise of the mixing layer or with incoming rain fronts. In-cloud and multilayer measurements are also available allowing a large range of additional investigations such as cloud-aerosol interactions or cloud droplet activation. From March to May 2009, LEOSPHERE deployed a WLS70 prototype unit at the Howard University Research Campus in Beltsville, Maryland, for the Water Vapor Validation Experiments (WAVES) from the initiative of the NOAA. The presence of numerous wind profilers, lidars and radio soundings was a perfect opportunity to test and improve this new compact and autonomous long range wind Lidar. The WLS70 showed Low Level Jet phenomena which have strong impact on air quality. In July 2009, the WLS70 took its definitive configuration with a new optical device installed on it allowing enhanced measurement range. New measurements were done at PNNL in Richland, Washington, and NASA Langley in Hampton, Virginia. These results are now processed and will bring a further proof on reliability and accuracy. During these intensive inter comparison campaigns the WLS70 Wind Lidar was validated against Lidars, Radars, Sodars and anemometers. The results show mostly a very good agreement between the instruments. Moreover, the measurements put in evidence both horizontal and vertical wind speed and wind direction vertical profiles and atmosphere structure (PBL height , clouds base) derived from Lidar data with good time resolution (10s/profile), good range resolution (50m from 100m to 2000m), and good velocity accuracy (<0.2m/s).

Fiber-Coupled Planar Light-Wave Circuit for Seed Laser Control in High Spectral Resolution Lidar Systems

NASA Technical Reports Server (NTRS)

Cook, Anthony; McNeil, Shirley; Switzer, Gregg; Battle, Philip

2010-01-01

Precise laser remote sensing of aerosol extinction and backscatter in the atmosphere requires a high-power, pulsed, frequency doubled Nd:YAG laser that is wavelength- stabilized to a narrow absorption line such as found in iodine vapor. One method for precise wavelength control is to injection seed the Nd:YAG laser with a low-power CW laser that is stabilized by frequency converting a fraction of the beam to 532 nm, and to actively frequency-lock it to an iodine vapor absorption line. While the feasibility of this approach has been demonstrated using bulk optics in NASA Langley s Airborne High Spectral Resolution Lidar (HSRL) program, an ideal, lower cost solution is to develop an all-waveguide, frequency-locked seed laser in a compact, robust package that will withstand the temperature, shock, and vibration levels associated with airborne and space-based remote sensing platforms. A key technology leading to this miniaturization is the integration of an efficient waveguide frequency doubling element, and a low-voltage phase modulation element into a single, monolithic, planar light-wave circuit (PLC). The PLC concept advances NASA's future lidar systems due to its compact, efficient and reliable design, thus enabling use on small aircraft and satellites. The immediate application for this technology is targeted for NASA Langley's HSRL system for aerosol and cloud characterization. This Phase I effort proposes the development of a potassium titanyl phosphate (KTP) waveguide phase modulator for future integration into a PLC. For this innovation, the proposed device is the integration of a waveguide-based frequency doubler and phase modulator in a single, fiber pigtail device that will be capable of efficient second harmonic generation of 1,064-nm light and subsequent phase modulation of the 532 nm light at 250 MHz, providing a properly spectrally formatted beam for HSRL s seed laser locking system. Fabrication of the integrated PLC chip for NASA Langley, planned for the Phase II effort, will require full integration and optimization of the waveguide components (SHG waveguide, splitters, and phase modulator) onto a single, monolithic device. The PLC will greatly reduce the size and weight, improve electrical- to-optical efficiency, and significantly reduce the cost of NASA Langley s current stabilized HSRL seed laser system built around a commercial off-the-shelf seed laser that is free-space coupled to a bulk doubler and bulk phase modulator.

Lower-free tropospheric ozone dial measurements over Athens, Greece

NASA Astrophysics Data System (ADS)

Mytilinaios, Michail; Papayannis, Alexandros; Tsaknakis, Georgios

2018-04-01

A compact ozone differential absorption lidar (DIAL) was implemented at the Laboratory of Laser Remote Sensing of the National Technical University of Athens (NTUA), in Athens, Greece. The DIAL system is based on a Nd:YAG laser emitting at 266 nm. A high-pressure Raman cell, filled with D2, was used to generate the λON and λOFF laser wavelength pairs (i.e., 266-289 nm and 289-316 nm, respectively) based on the Stimulated Raman Scattering (SRS) effect. The system was run during daytime and nighttime conditions to obtain the vertical profile of tropospheric ozone in the Planetary Boundary Layer (PBL) and the adjacent free troposphere.

Temporal Analysis and Automatic Calibration of the Velodyne HDL-32E LiDAR System

NASA Astrophysics Data System (ADS)

Chan, T. O.; Lichti, D. D.; Belton, D.

2013-10-01

At the end of the first quarter of 2012, more than 600 Velodyne LiDAR systems had been sold worldwide for various robotic and high-accuracy survey applications. The ultra-compact Velodyne HDL-32E LiDAR has become a predominant sensor for many applications that require lower sensor size/weight and cost. For high accuracy applications, cost-effective calibration methods with minimal manual intervention are always desired by users. However, the calibrations are complicated by the Velodyne LiDAR's narrow vertical field of view and the very highly time-variant nature of its measurements. In the paper, the temporal stability of the HDL-32E is first analysed as the motivation for developing a new, automated calibration method. This is followed by a detailed description of the calibration method that is driven by a novel segmentation method for extracting vertical cylindrical features from the Velodyne point clouds. The proposed segmentation method utilizes the Velodyne point cloud's slice-like nature and first decomposes the point clouds into 2D layers. Then the layers are treated as 2D images and are processed with the Generalized Hough Transform which extracts the points distributed in circular patterns from the point cloud layers. Subsequently, the vertical cylindrical features can be readily extracted from the whole point clouds based on the previously extracted points. The points are passed to the calibration that estimates the cylinder parameters and the LiDAR's additional parameters simultaneously by constraining the segmented points to fit to the cylindrical geometric model in such a way the weighted sum of the adjustment residuals are minimized. The proposed calibration is highly automatic and this allows end users to obtain the time-variant additional parameters instantly and frequently whenever there are vertical cylindrical features presenting in scenes. The methods were verified with two different real datasets, and the results suggest that up to 78.43% accuracy improvement for the HDL-32E can be achieved using the proposed calibration method.

Coherent Doppler lidar for automated space vehicle, rendezvous, station-keeping and capture

NASA Technical Reports Server (NTRS)

Dunkin, James A.

1991-01-01

Recent advances in eye-safe, short wavelength solid-state lasers offer real potential for the development of compact, reliable, light-weight, efficient coherent lidar. Laser diode pumping of these devices has been demonstrated, thereby eliminating the need for flash lamp pumping, which has been a major drawback to the use of these lasers in space based applications. Also these lasers now have the frequency stability required to make them useful in coherent lidar, which offers all of the advantages of non-coherent lidar, but with the additional advantage that direct determination of target velocity is possible by measurement of the Doppler shift. By combining the Doppler velocity measurement capability with the inherent high angular resolution and range accuracy of lidar it is possible to construct Doppler images of targets for target motion assessment. A coherent lidar based on a Tm,Ho:YAG 2-micrometer wavelength laser was constructed and successfully field tested on atmospheric targets in 1990. This lidar incorporated an all solid state (laser diode pumped) master oscillator, in conjunction with a flash lamp pumped slave oscillator. Solid-state laser technology is rapidly advancing, and with the advent of high efficiency, high power, semiconductor laser diodes as pump sources, all-solid-state, coherent lidars are a real possibility in the near future. MSFC currently has a feasibility demonstration effort under way which will involve component testing, and preliminary design of an all-solid-state, coherent lidar for automatic rendezvous, and capture. This two year effort, funded by the Director's Discretionary Fund is due for completion in 1992.

Lidar Sensor Performance in Closed-Loop Flight Testing of the Morpheus Rocket-Propelled Lander to a Lunar-Like Hazard Field

NASA Technical Reports Server (NTRS)

Roback, Vincent E.; Pierrottet, Diego F.; Amzajerdian, Farzin; Barnes, Bruce W.; Hines, Glenn D.; Petway, Larry B.; Brewster, Paul F.; Kempton, Kevin S.; Bulyshev, Alexander E.

2015-01-01

For the first time, a suite of three lidar sensors have been used in flight to scan a lunar-like hazard field, identify a safe landing site, and, in concert with an experimental Guidance, Navigation, and Control (GN&C) system, guide the Morpheus autonomous, rocket-propelled, free-flying test bed to a safe landing on the hazard field. The lidar sensors and GN&C system are part of the Autonomous Precision Landing and Hazard Detection and Avoidance Technology (ALHAT) project which has been seeking to develop a system capable of enabling safe, precise crewed or robotic landings in challenging terrain on planetary bodies under any ambient lighting conditions. The 3-D imaging flash lidar is a second generation, compact, real-time, air-cooled instrument developed from a number of cutting-edge components from industry and NASA and is used as part of the ALHAT Hazard Detection System (HDS) to scan the hazard field and build a 3-D Digital Elevation Map (DEM) in near-real time for identifying safe sites. The flash lidar is capable of identifying a 30 cm hazard from a slant range of 1 km with its 8 cm range precision at 1 sigma. The flash lidar is also used in Hazard Relative Navigation (HRN) to provide position updates down to a 250m slant range to the ALHAT navigation filter as it guides Morpheus to the safe site. The Doppler Lidar system has been developed within NASA to provide velocity measurements with an accuracy of 0.2 cm/sec and range measurements with an accuracy of 17 cm both from a maximum range of 2,200 m to a minimum range of several meters above the ground. The Doppler Lidar's measurements are fed into the ALHAT navigation filter to provide lander guidance to the safe site. The Laser Altimeter, also developed within NASA, provides range measurements with an accuracy of 5 cm from a maximum operational range of 30 km down to 1 m and, being a separate sensor from the flash lidar, can provide range along a separate vector. The Laser Altimeter measurements are also fed into the ALHAT navigation filter to provide lander guidance to the safe site. The flight tests served as the culmination of the TRL 6 journey for the lidar suite and included launch from a pad situated at the NASA-Kennedy Space Center Shuttle Landing Facility (SLF) runway, a lunar-like descent trajectory from an altitude of 250m, and landing on a lunar-like hazard field of rocks, craters, hazardous slopes, and safe sites 400m down-range just off the North end of the runway. The tests both confirmed the expected performance and also revealed several challenges present in the flight-like environment which will feed into future TRL advancement of the sensors. The flash lidar identified hazards as small as 30 cm from the maximum slant range of 450 m which Morpheus could provide, however, it was occasionally susceptible to an increase in range noise due to heated air from the Morpheus rocket plume which entered its Field-of-View (FOV). The flash lidar was also susceptible to pre-triggering on dust during the HRN phase which was created during launch and transported by the wind. The Doppler Lidar provided velocity and range measurements to the expected accuracy levels yet it was also susceptible to signal degradation due to air heated by the rocket engine. The Laser Altimeter, operating with a degraded transmitter laser, also showed signal attenuation over a few seconds at a specific phase of the flight due to the heat plume generated by the rocket engine.

Operational processing and cloud boundary detection from micro pulse lidar data

NASA Technical Reports Server (NTRS)

Campbell, James R.; Hlavka, Dennis L.; Spinhirne, James D.; Scott, V. Stanley., III; Turner, David D.

1998-01-01

Micro Pulse Lidar (MPL) was developed at NASA Goddard Space Flight Center (GSFC) as the result of research on space-borne lidar techniques. It was designed to provide continuous, unattended observations of all significant atmospheric cloud and aerosol structure with a rugged, compact system design and the benefit of eye safety (Spinhirne 1993). The significant eye safety feature is achieved by using low pulse energies and high pulse repetition rates compared to standard lidar systems. MPL systems use a diode pumped 10 microj, 2500 Hz doubled Nd:YLF laser. In addition, a solid state Geiger mode avalanche photo diode (GAPD) photon counting detector is used allowing for quantum efficiencies approaching 70%. Other design features have previously been noted by Spinhirne (1995). Though a commercially available instrument, with nearly 20 systems operating around the world, the most extensive MPL work has come from those operated by the Atmospheric Radiation Measurement (ARM) (Stokes and Schwartz 1994) program. The diverse ability of the instrument relating to the measurement of basic cloud macrophysical structure and both cloud and aerosol radiative properties well suits the ARM research philosophy. MPL data can be used to yield many parameters including cloud boundary heights to the limit of signal attenuation, cloud scattering cross sections and optical thicknesses, planetary boundary layer heights and aerosol scattering profiles, including those into the stratosphere in nighttime cases (Hlavka et al 1996). System vertical resolution ranges from 30 m to 300 m (i.e. high and low resolution respectively) depending on system design. The lidar research group at GSFC plays an advisory role in the operation, calibration and maintenance of NASA and ARM owned MPL systems. Over the past three years, processing software and system correction techniques have been developed in anticipation of the increasing population of systems amongst the community. Datasets produced by three ARM-owned systems have served as the basis for this development. With two operating at the southern Great Plains Cloud and Radiation Testbed Site (SGP CART) since December 1993 and another at the Manus Island Atmospheric Radiation and Cloud Station (TWP ARCS) location in the tropical western Pacific since February 1997, the ARM archive contains over 4 years of observations. In addition, high resolution systems planning to come on-line at the North Slope, AK CART shortly with another scheduled to follow at the TWP ARCS-II will diversify this archive with more extensive observations.

Airborne Remote Sensing of River Flow and Morphology

NASA Astrophysics Data System (ADS)

Zuckerman, S.; Anderson, S. P.; McLean, J.; Redford, R.

2014-12-01

River morphology, surface slope and flow are some of the fundamental measurements required for surface water monitoring and hydrodynamic research. This paper describes a method of combining bathymetric lidar with space-time processing of mid-wave infrared (MWIR) imagery to simultaneously measure bathymetry, currents and surface slope from an airborne platform. In May 2014, Areté installed a Pushbroom Imaging Lidar for Littoral Surveillance (PILLS) and a FLIR SC8000 MWIR imaging system sampling at 2 Hz in a small twin-engine aircraft. Data was collected over the lower Colorado River between Picacho Park and Parker. PILLS is a compact bathymetric lidar based on streak-tube sensor technology. It provides channel and bank topography and water surface elevation at 1 meter horizontal scales and 25 cm vertical accuracy. Surface currents are derived from the MWIR imagery by tracking surface features using a cross correlation algorithm. This approach enables the retrieval of currents along extended reaches at the forward speed of the aircraft with spatial resolutions down to 5 m with accuracy better than 10 cm/s. The fused airborne data captures current and depth variability on scales of meters over 10's of kilometers collected in just a few minutes. The airborne MWIR current retrievals are combined with the bathymetric lidar data to calculate river discharge which is then compared with real-time streamflow stations. The results highlight the potential for improving our understanding of complex river environments with simultaneous collections from multiple airborne sensors.

A compact large-format streak tube for imaging lidar

NASA Astrophysics Data System (ADS)

Hui, Dandan; Luo, Duan; Tian, Liping; Lu, Yu; Chen, Ping; Wang, Junfeng; Sai, Xiaofeng; Wen, Wenlong; Wang, Xing; Xin, Liwei; Zhao, Wei; Tian, Jinshou

2018-04-01

The streak tubes with a large effective photocathode area, large effective phosphor screen area, and high photocathode radiant sensitivity are essential for improving the field of view, depth of field, and detectable range of the multiple-slit streak tube imaging lidar. In this paper, a high spatial resolution, large photocathode area, and compact meshless streak tube with a spherically curved cathode and screen is designed and tested. Its spatial resolution reaches 20 lp/mm over the entire Φ28 mm photocathode working area, and the simulated physical temporal resolution is better than 30 ps. The temporal distortion in our large-format streak tube, which is shown to be a non-negligible factor, has a minimum value as the radius of curvature of the photocathode varies. Furthermore, the photocathode radiant sensitivity and radiant power gain reach 41 mA/W and 18.4 at the wavelength of 550 nm, respectively. Most importantly, the external dimensions of our streak tube are no more than Φ60 mm × 110 mm.

Progress in Laser Risk Reduction for 1 micron lasers at GSFC

NASA Technical Reports Server (NTRS)

Heaps, William S.

2007-01-01

In recent years, lasers have proven themselves to be invaluable to a variety of remote sensing applications. LIDAR techniques have been used to measure atmospheric aerosols and a variety of trace species, profile winds, and develop high resolution topographical maps. Often it would be of great advantage to make these measurements from an orbiting satellite. Unfortunately, the space environment is a challenging one for the high power lasers that would enable many LIDAR missions. Optical mounts must maintain precision alignment during and after launch. Outgassing materials in the vacuum of space lead to contamination of laser optics. Electronic components and optical materials must survive the space environment, including a vacuum atmosphere, thermal cycling, and radiation exposure. Laser designs must be lightweight, compact, and energy efficient. Many LIDAR applications require frequency conversion systems that have never been designed or tested for use in space. For the last six years the National Aeronautical and Space Administration (NASA) has undertaken a program specifically directed at addressing the durability and long term reliability issues that face space-borne lasers. The effort is shared between NASA Goddard Space Flight Center in Greenbelt, Maryland, and NASA Langley Research Center in Hampton, Virginia. This paper is an overview of the issues facing space-borne lasers and the efforts that Goddard has been pursuing to address them.

Development of a Portable, Ground-based Ozone Lidar Instrument for Tropospheric Ozone Research and Educational Training

NASA Technical Reports Server (NTRS)

Chyba, Thomas; Zemker, Thomas; Fishman, Jack (Technical Monitor)

1999-01-01

The objective of this research project is to develop a portable, eye-safe, ground-based ozone lidar instrument specialized for ozone differential absorption lidar (DIAL) measurements in the troposphere. This research project directly supports the goal of NASA's Earth Science Enterprise to understand the distribution and budget of tropospheric ozone (objective 1.5 of the Earth Science Strategic Enterprise Plan, 1998-2002). It can participate in ground validation experiments for TES, a tropospheric ozone satellite mission due to be launched in 2002. It can also be utilized for correlative ground measurements in future GTE (Global Tropospheric Experiment) and space-based ozone lidar missions, such as ORACLE. Multiple ground-based ozone lidar systems would improve the data obtained through current ozone-sonde networks. This prototype instrument could to serve as the basic unit for these and other future monitoring projects requiring multi-instrument networks, such as that proposed for the Global Tropospheric Ozone Project (GTOP). GTOP is currently being formulated by a scientific panel of the International Global Atmospheric Chemistry Project to meet its goal to better understand the processes that control the global distribution of tropospheric ozone. In order for the lidar to be widely deployed in networks, it must be fairly easy to use and maintain as well as being cost-competitive with a ground station launching ozonesondes several times a day. A second 2-year grant to continue this effort with students participating in ground tests and system improvements has been awarded by the Office of Equal Employment Opportunities (OEOP). This project also supports existing NASA lidar missions through its development of advanced, compact lidar technology. Innovations in both transmitters and receivers have been made in this project. Finally, this system could be modified in the future to probe more deeply into the stratosphere. This could be accomplished by increasing the emitted energy or optimizing the wavelengths for this purpose. In addition to NASA, this system has applications to the EPA, NOAA, and the DOD. An AFOSR grant has been awarded based on the results of this effort to fund advanced transmitter development at medium (20-40 mJ) energies. A second proposal to the DOD with a letter of support from Air Force Research Laboratory, has been submitted to extend this uv laser technology to 100 mJ levels. Thus, this project has enabled students and faculty at Hampton University to begin to develop research efforts in support of the mission of the DOD. This instrument will be based at Hampton University (HU) to meet our educational goal to train students in lidar technology as well as atmospheric ozone data analysis and interpretation. It will be also available for off-site measurement campaigns and will serve as a test bed for further instrument development. Later development beyond this grant to extend the scientific usefulness of the instrument may include incorporation of an aerosol channel and upgrading the laser to make stratospheric ozone measurements. Seven undergraduates, three graduate students, and one postdoctoral. researcher (formerly an HU student) have been active participants in this research effort.

Synthetic aperture lidar as a future tool for earth observation

NASA Astrophysics Data System (ADS)

Turbide, Simon; Marchese, Linda; Terroux, Marc; Bergeron, Alain

2017-11-01

Synthetic aperture radar (SAR) is a tool of prime importance for Earth observation; it provides day and night capabilities in various weather conditions. State-of-the-art satellite SAR systems are a few meters in height and width and achieve resolutions of less than 1 m with revisit times on the order of days. Today's Earth observation needs demand higher resolution imaging together with timelier data collection within a compact low power consumption payload. Such needs are seen in Earth Observation applications such as disaster management of earthquakes, landslides, forest fires, floods and others. In these applications the availability of timely reliable information is critical to assess the extent of the disaster and to rapidly and safely deploy rescue teams. Synthetic aperture lidar (SAL) is based on the same basic principles as SAR. Both rely on the acquisition of multiple electromagnetic echoes to emulate a large antenna aperture providing the ability to produce high resolution images. However, in SAL, much shorter optical wavelengths (1.5 μm) are used instead of radar ones (wavelengths around 3 cm). Resolution being related to the wavelength, multiple orders of magnitude of improvement could be theoretically expected. Also, the sources, the detector, and the components are much smaller in optical domain than those for radar. The resulting system can thus be made compact opening the door to deployment onboard small satellites, airborne platforms and unmanned air vehicles. This has a strong impact on the time required to develop, deploy and use a payload. Moreover, in combination with airborne deployment, revisit times can be made much smaller and accessibility to the information can become almost in real-time. Over the last decades, studies from different groups have been done to validate the feasibility of a SAL system for 2D imagery and more recently for 3D static target imagery. In this paper, an overview of the advantages of this emerging technology will be presented. As well, simulations and laboratory demonstrations of deformation mapping using a tabletop synthetic aperture lidar system operated at 1.5 μm are reviewed. The transmitter and receptor of the fiber-based system are mounted on a translation stage which move at a constant speed relatively to the target (sand) located 25 cm away. The change in the 3D profile of the target is thereafter monitored with sub-millimeter precision using the multiple-pass SAL system. Results obtained with a SAL laboratory prototype are reviewed along with the potential applications for Earth observation.

Wyoming Cloud Lidar: instrument description and applications.

PubMed

Wang, Zhien; Wechsler, Perry; Kuestner, William; French, Jeffrey; Rodi, Alfred; Glover, Brent; Burkhart, Matthew; Lukens, Donal

2009-08-03

The Wyoming Cloud Lidar (WCL), a compact two-channel elastic lidar, was designed to obtain cloud measurements together with the Wyoming Cloud Radar (WCR) on the University of Wyoming King Air and the National Science Foundation/National Center of Atmospheric Research C-130 aircraft. The WCL has been deployed in four field projects under a variety of atmospheric and cloud conditions during the last two years. Throughout these campaigns, it has exhibited the needed reliability for turn-key operation from aircraft. We provide here an overview of the instrument and examples to illustrate the measurements capability of the WCL. Although the WCL as a standalone instrument can provide unique measurements for cloud and boundary layer aerosol studies, the synergy of WCL and WCR measurements coupled with in situ sampling from an aircraft provide a significant step forward in our ability to observe and understand cloud microphysical property evolution.

Lidar Sensor Performance in Closed-Loop Flight Testing of the Morpheus Rocket-Propelled Lander to a Lunar-Like Hazard Field

NASA Technical Reports Server (NTRS)

Roback, V. Eric; Pierrottet, Diego F.; Amzajerdian, Farzin; Barnes, Bruce W.; Bulyshev, Alexander E.; Hines, Glenn D.; Petway, Larry B.; Brewster, Paul F.; Kempton, Kevin S.

2015-01-01

For the first time, a suite of three lidar sensors have been used in flight to scan a lunar-like hazard field, identify a safe landing site, and, in concert with an experimental Guidance, Navigation, and Control (GN&C) system, help to guide the Morpheus autonomous, rocket-propelled, free-flying lander to that safe site on the hazard field. The lidar sensors and GN&C system are part of the Autonomous Precision Landing and Hazard Detection and Avoidance Technology (ALHAT) project which has been seeking to develop a system capable of enabling safe, precise crewed or robotic landings in challenging terrain on planetary bodies under any ambient lighting conditions. The 3-D imaging Flash Lidar is a second generation, compact, real-time, aircooled instrument developed from a number of components from industry and NASA and is used as part of the ALHAT Hazard Detection System (HDS) to scan the hazard field and build a 3-D Digital Elevation Map (DEM) in near-real time for identifying safe sites. The Flash Lidar is capable of identifying a 30 cm hazard from a slant range of 1 km with its 8 cm range precision (1-s). The Flash Lidar is also used in Hazard Relative Navigation (HRN) to provide position updates down to a 250m slant range to the ALHAT navigation filter as it guides Morpheus to the safe site. The Navigation Doppler Lidar (NDL) system has been developed within NASA to provide velocity measurements with an accuracy of 0.2 cm/sec and range measurements with an accuracy of 17 cm both from a maximum range of 2,200 m to a minimum range of several meters above the ground. The NDLâ€"TM"s measurements are fed into the ALHAT navigation filter to provide lander guidance to the safe site. The Laser Altimeter (LA), also developed within NASA, provides range measurements with an accuracy of 5 cm from a maximum operational range of 30 km down to 1 m and, being a separate sensor from the Flash Lidar, can provide range along a separate vector. The LA measurements are also fed into the ALHAT navigation filter to provide lander guidance to the safe site. The flight tests served as the culmination of the TRL 6 journey for the ALHAT system and included launch from a pad situated at the NASA-Kennedy Space Center Shuttle Landing Facility (SLF) runway, a lunar-like descent trajectory from an altitude of 250m, and landing on a lunar-like hazard field of rocks, craters, hazardous slopes, and safe sites 400m down-range just off the North end of the runway. The tests both confirmed the expected performance and also revealed several challenges present in the flight-like environment which will feed into future TRL advancement of the sensors. Guidance provided by the ALHAT system was impeded in portions of the trajectory and intermittent near the end of the trajectory due to optical effects arising from air heated by the rocket engine. The Flash Lidar identified hazards as small as 30 cm from the maximum slant range of 450 m which Morpheus could provide; however, it was occasionally susceptible to an increase in range noise due to scintillation arising from air heated by the Morpheus rocket engine which entered its Field-of-View (FOV). The Flash Lidar was also susceptible to pre-triggering, during the HRN phase, on a dust cloud created during launch and transported down-range by the wind. The NDL provided velocity and range measurements to the expected accuracy levels yet it was also susceptible to signal degradation due to air heated by the rocket engine. The LA, operating with a degraded transmitter laser, also showed signal attenuation over a few seconds at a specific phase of the flight due to the heat plume generated by the rocket engine.

Design and implementation of a preprocessing system for a sodium lidar

NASA Technical Reports Server (NTRS)

Voelz, D. G.; Sechrist, C. F., Jr.

1983-01-01

A preprocessing system, designed and constructed for use with the University of Illinois sodium lidar system, was developed to increase the altitude resolution and range of the lidar system and also to decrease the processing burden of the main lidar computer. The preprocessing system hardware and the software required to implement the system are described. Some preliminary results of an airborne sodium lidar experiment conducted with the preprocessing system installed in the sodium lidar are presented.

Advanced Detector and Waveform Digitizer for Water Vapor DIAL Systems

NASA Technical Reports Server (NTRS)

Refaat, Tamer F.; Luck, William S., Jr.; DeYoung, Russell J.

1998-01-01

Measurement of atmospheric water vapor has become a major requirement for understanding moist-air processes. Differential absorption lidar (DIAL) is a technique best suited for the measurement of atmospheric water vapor. NASA Langley Research Center is continually developing improved DIAL systems. One aspect of current development is focused on the enhancement of a DIAL receiver by applying state-of-the-art technology in building a new compact detection system that will be placed directly on the DIAL receiver telescope. The newly developed detection system has the capability of being digitally interfaced with a simple personal computer, using a discrete input/output interface. This has the potential of transmitting digital data over relatively long distances instead of analog signals, which greatly reduces measurement noise. In this paper, we discuss some results from the new compact water vapor DIAL detection system which includes a silicon based avalanche photodiode (APD) detector, a 14-bit, 10-MHz waveform digitizer, a microcontroller and other auxiliary electronics. All of which are contained on a small printed-circuit-board. This will significantly reduce the weight and volume over the current CAMAC system and eventually will be used in a water vapor DIAL system on an unpiloted atmospheric vehicle (UAV) aircraft, or alternatively on an orbiting spacecraft.

Study of Ground Subsidence in North West Houston using GPS, LiDAR and InSAR techniques

NASA Astrophysics Data System (ADS)

Karacay, A.; Khan, S. D.

2012-12-01

Land subsidence can be caused by natural or human activities, such as carbonate dissolution, extraction of material from mines, soil compaction and fluid withdrawal. This phenomenon affects many cities around the world, such as Nagoya-Japan, Venice-Italy, San Joaquin Valley and Long Beach in California. Recent work by Engelkemeir et al, (2010), suggested that subsidence occurred as high as 5.6 cm/year in northwest Houston. The processes that may contribute to land subsidence in the Houston-Galveston area includes faulting, soil compaction, salt tectonic, water pumping and hydrocarbon extraction. This study aims to assess the possible role of water pumping on subsidence. Northwest Houston has two aquifer systems, the Evangeline and Chicot aquifers that dip in the southeast direction. The effect of water pumping on subsidence from these two aquifers was monitored using InSAR, GPS and LiDAR data. The data from eleven GPS stations were processed using Online Positioning User Service (OPUS) of National Geodetic Survey (NGS). Three of these GPS stations are Continuously Operating Reference Stations (CORS) and eight are Port-A-Measure (PAM) sites. All the GPS data were obtained from Harris-Galveston Subsidence District (HGSD). CORS sites were used as reference stations for processing GPS data from the PAM stations. GPS data show that subsidence rate in northwest Houston decreased to approximately 2 cm/year. In addition, the surface deformation is also estimated using Light Detection and Ranging (LiDAR) technique. For this purpose, raw LiDAR (LAS-Long ASCII Standart) files of 2001 and 2008 were processed. The subsidence rate near the Hockley Fault was calculated by applying zonal statistics method on LiDAR data which shows about 10 cm of subsidence in nine years. This result is supported by processed GPS data from PAM site 48 that show subsidence rate of 1.3 cm/yr. For the InSAR (Interferometric Synthetic Aperture Radar) technique, an image pair of PALSAR (The Phased Array type L-band Synthetic Aperture Radar) for 2008 was processed using Sarscape ENVI. The result demonstrates both uplift (approximately 5 mm near the Tomball salt dome) and subsidence (approximately 5.3 mm on the west part of Tomball region). In order to improve results, other image pairs from PALSAR, ERS1/2 and ENVISAT are being processed to monitor surface changes before and after 2000. Changes of groundwater level in the study area were observed, in order to distinguish the amount of land subsidence caused by groundwater withdrawal. The groundwater historical observation data were taken from The USGS National Water Information System (NWIS). The results of the groundwater level between 1990 and 2011 show approximately 0.5 m per year of water decline in the study area. Results of these complementary techniques will help in assessing the possible role of the water pumping from the subsurface on the subsidence in the area.

Development of Prototype Micro-Lidar using Narrow Linewidth Semiconductor Lasers for Mars Boundary Layer Wind and Dust Opacity Profiles

NASA Technical Reports Server (NTRS)

Menzies, Robert T.; Cardell, Greg; Chiao, Meng; Esproles, Carlos; Forouhar, Siamak; Hemmati, Hamid; Tratt, David

1999-01-01

We have developed a compact Doppler lidar concept which utilizes recent developments in semiconductor diode laser technology in order to be considered suitable for wind and dust opacity profiling in the Mars lower atmosphere from a surface location. The current understanding of the Mars global climate and meteorology is very limited, with only sparse, near-surface data available from the Viking and Mars Pathfinder landers, supplemented by long-range remote sensing of the Martian atmosphere. The in situ measurements from a lander-based Doppler lidar would provide a unique dataset particularly for the boundary layer. The coupling of the radiative properties of the lower atmosphere with the dynamics involves the radiative absorption and scattering effects of the wind-driven dust. Variability in solar irradiance, on diurnal and seasonal time scales, drives vertical mixing and PBL (planetary boundary layer) thickness. The lidar data will also contribute to an understanding of the impact of wind-driven dust on lander and rover operations and lifetime through an improvement in our understanding of Mars climatology. In this paper we discuss the Mars lidar concept, and the development of a laboratory prototype for performance studies, using, local boundary layer and topographic target measurements.

Monolithic master oscillator power amplifier at 1.58 μm for lidar measurements

NASA Astrophysics Data System (ADS)

Faugeron, M.; Krakowski, M.; Robert, Y.; Vinet, E.; Primiani, P.; Le Goëc, J. P.; Parillaud, O.; van Dijk, F.; Vilera, M.; Consoli, A.; Tijero, J. M. G.; Esquivias, I.

2017-11-01

Nowadays the interest in high power semiconductor devices is growing for applications such as telemetry, lidar system or free space communications. Indeed semiconductor devices can be an alternative to solid state lasers because they are more compact and less power consuming. These characteristics are very important for constrained and/or low power supply environment such as airplanes or satellites. Lots of work has been done in the 800-1200 nm range for integrated and free space Master Oscillator Power Amplifier (MOPA) [1]-[3]. At 1.5 μm, the only commercially available MOPA is from QPC [4]: the fibred output power is about 700 mW and the optical linewidth is 500 kHz. In this paper, we first report on the simulations we have done to determine the appropriate vertical structure and architecture for a good MOPA at 1.58 μm (section II). Then we describe the fabrication of the devices (section III). Finally we report on the optical and electrical measurements we have done for various devices (section IV).

Barium Nitrate Raman Laser Development for Remote Sensing of Ozone

NASA Technical Reports Server (NTRS)

McCray, Christopher L.; Chyba, Thomas H.

1997-01-01

In order to understand the impact of anthropogenic emissions upon the earth's environment, scientists require remote sensing techniques which are capable of providing range-resolved measurements of clouds, aerosols, and the concentrations of several chemical constituents of the atmosphere. The differential absorption lidar (DIAL) technique is a very promising method to measure concentration profiles of chemical species such as ozone and water vapor as well as detect the presence of aerosols and clouds. If a suitable DIAL system could be deployed in space, it would provide a global data set of tremendous value. Such systems, however, need to be compact, reliable, and very efficient. In order to measure atmospheric gases with the DIAL technique, the laser transmitter must generate suitable on-line and off-line wavelength pulse pairs. The on-line pulse is resonant with an absorption feature of the species of interest. The off-line pulse is tuned so that it encounters significantly less absorption. The relative backscattered power for the two pulses enables the range-resolved concentration to be computed. Preliminary experiments at NASA LaRC suggested that the solid state Raman shifting material, Ba(NO3)2, could be utilized to produce these pulse pairs. A Raman oscillator pumped at 532 nm by a frequency-doubled Nd:YAG laser can create first Stokes laser output at 563 nm and second Stokes output at 599 nm. With frequency doublers, UV output at 281 nm and 299 nm can be subsequently obtained. This all-solid state system has the potential to be very efficient, compact, and reliable. Raman shifting in Ba(NO3)2, has previously been performed in both the visible and the infrared. The first Raman oscillator in the visible region was investigated in 1986 with the configurations of plane-plane and unstable telescopic resonators. However, most of the recent research has focused on the development of infrared sources for eye-safe lidar applications.

Polarization Lidar for Shallow Water Supraglacial Lake Depth Measurement

NASA Astrophysics Data System (ADS)

Mitchell, S.; Adler, J.; Thayer, J. P.; Hayman, M.

2010-12-01

A bathymetric, polarization lidar system transmitting at 532 nanometers and using a single photomultiplier tube is developed for applications of shallow water depth measurement, in particular those often found in supraglacial lakes of the ablation zone on the Greenland Ice Sheet. The technique exploits polarization attributes of the probed water body to isolate surface and floor returns, enabling constant fraction detection schemes to determine depth. The minimum resolvable water depth is no longer dictated by the system’s laser or detector pulse width and can achieve better than an order of magnitude improvement over current water depth determination techniques. In laboratory tests, a Nd:YAG microchip laser coupled with polarization optics, a photomultiplier tube, a constant fraction discriminator and a time to digital converter are used to target various water depths, using ice as the floor to simulate a supraglacial lake. Measurement of 1 centimeter water depths with an uncertainty of ±3 millimeters are demonstrated using the technique. This novel technique enables new approaches to designing laser bathymetry systems for shallow depth determination from remote platforms while not compromising deep water depth measurement, and will support comprehensive hydrodynamic studies of supraglacial lakes. Additionally, the compact size and low weight (<15 kg) of the field system currently in development presents opportunities for use in small unmanned aircraft systems (UAS) for large areal surveys of the ablation zone.

Test Bed Doppler Wind Lidar and Intercomparison Facility At NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Kavaya, Michael J.; Koch, Grady J.; Petros, Mulugeta; Barnes, Bruce W.; Beyon, Jeffrey; Amzajerdian, Farzin; Yu, Ji-Rong; Singh, Upendra N.

2004-01-01

State of the art 2-micron lasers and other lidar components under development by NASA are being demonstrated and validated in a mobile test bed Doppler wind lidar. A lidar intercomparison facility has been developed to ensure parallel alignment of up to 4 Doppler lidar systems while measuring wind. Investigations of the new components; their operation in a complete system; systematic and random errors; the hybrid (joint coherent and direct detection) approach to global wind measurement; and atmospheric wind behavior are planned. Future uses of the VALIDAR (VALIDation LIDAR) mobile lidar may include comparison with the data from an airborne Doppler wind lidar in preparation for validation by the airborne system of an earth orbiting Doppler wind lidar sensor.

Evaluation of performance of silicon photomultipliers in lidar applications

NASA Astrophysics Data System (ADS)

Vinogradov, Sergey L.

2017-05-01

Silicon Photomultipliers (SiPMs) are a well-recognized new generation of photon number resolving avalanche photodetectors. Many advantages - a high gain with an ultra-low excess noise of multiplication, multi-pixel architecture, relatively low operating voltage - make SiPMs very competitive in a growing number of applications. Challenging demands of LIDAR applications for a receiver having high sensitivity starting from single photons, superior time-offlight resolution, robustness including surviving at bright light flashes, solid-state compactness and more, are expected to be feasible for the SiPMs. Despite some known drawbacks, namely crosstalk, afterpulsing, dark noise, limited dynamic range, SiPMs are already considered as promising substitutes for conventional APDs and PMTs in LIDAR applications. However, these initial considerations are based on a rather simplified representation of the SiPM as a generic LIDAR receiver described by generic expressions. This study is focused on a comprehensive evaluation of a SiPM potential considering essential features of this new technology, which could affect applicability and performance of SiPMs as LIDAR receivers. Namely, an excess noise due to correlated processes of crosstalk and afterpulsing, are included into account utilizing the well-established framework of analytical probabilistic models. The analysis of SiPM performance in terms of a photon number and time resolution clarifies their competitiveness over conventional APD and PMT and anticipates the development of next SiPM generations.

The design, development, and test of balloonborne and groundbased lidar systems. Volume 3: Groundbased lidar systems

NASA Astrophysics Data System (ADS)

Shepherd, O.; Aurilio, G.; Bucknam, R. D.; Hurd, A. G.; Robertie, N. F.

1991-06-01

This is Volume 3 of a three volume final report on the design, development and test of balloonborne and groundbased lidar systems. Volume 1 describes the design and fabrication of a balloonborne CO2 coherent payload to measure the 10.6 micrometers backscatter from atmospheric aerosols as a function of altitude. Volume 2 describes the August 1987 flight test of Atmospheric Balloonborne Lidar Experiment, ABLE 2. In this volume we describe groundbased lidar development and measurements. A design was developed for installation of the ABLE lidar in the GL rooftop dome. A transportable shed was designed to house the ABLE lidar at the various remote measurement sites. Refurbishment and modification of the ABLE lidar were completed to permit groundbased lidar measurements of clouds and aerosols. Lidar field measurements were made at Ascension Island during SABLE 89. Lidar field measurements were made at Terciera, Azores during GABLE 90. These tasks have been successfully completed, and recommendations for further lidar measurements and data analysis have been made.

Cyclops: single-pixel imaging lidar system based on compressive sensing

NASA Astrophysics Data System (ADS)

Magalhães, F.; Correia, M. V.; Farahi, F.; Pereira do Carmo, J.; Araújo, F. M.

2017-11-01

Mars and the Moon are envisaged as major destinations of future space exploration missions in the upcoming decades. Imaging LIDARs are seen as a key enabling technology in the support of autonomous guidance, navigation and control operations, as they can provide very accurate, wide range, high-resolution distance measurements as required for the exploration missions. Imaging LIDARs can be used at critical stages of these exploration missions, such as descent and selection of safe landing sites, rendezvous and docking manoeuvres, or robotic surface navigation and exploration. Despite these devices have been commercially available and used for long in diverse metrology and ranging applications, their size, mass and power consumption are still far from being suitable and attractive for space exploratory missions. Here, we describe a compact Single-Pixel Imaging LIDAR System that is based on a compressive sensing technique. The application of the compressive codes to a DMD array enables compression of the spatial information, while the collection of timing histograms correlated to the pulsed laser source ensures image reconstruction at the ranged distances. Single-pixel cameras have been compared with raster scanning and array based counterparts in terms of noise performance, and proved to be superior. Since a single photodetector is used, a better SNR and higher reliability is expected in contrast with systems using large format photodetector arrays. Furthermore, the event of failure of one or more micromirror elements in the DMD does not prevent full reconstruction of the images. This brings additional robustness to the proposed 3D imaging LIDAR. The prototype that was implemented has three modes of operation. Range Finder: outputs the average distance between the system and the area of the target under illumination; Attitude Meter: provides the slope of the target surface based on distance measurements in three areas of the target; 3D Imager: produces 3D ranged images of the target surface. The implemented prototype demonstrated a frame rate of 30 mHz for 16x16 pixels images, a transversal (xy) resolution of 2 cm at 10 m for images with 64x64 pixels and the range (z) resolution proved to be better than 1 cm. The experimental results obtained for the "3D imaging" mode of operation demonstrated that it was possible to reconstruct spherical smooth surfaces. The proposed solution demonstrates a great potential for: miniaturization; increase spatial resolution without using large format detector arrays; eliminate the need for scanning mechanisms; implementing simple and robust configurations.

A portable lidar using a diode-pumped YAG laser

NASA Technical Reports Server (NTRS)

Takeuchi, N.; Okumura, H.; Sugita, T.; Matsumoto, H.; Yamaguchi, S.

1992-01-01

A Mie lidar system is technically established and is used for monitoring air pollution, stratospheric and boundary layer aerosol distribution, plume dispersion, visibility, and the study of atmospheric structure and cloud physics. However, a lidar system is not widely used because of its cumbersome handling and unwieldy portability. Although the author developed a laser diode lidar system based on RM-CW technique, it has a limit of measurement distance. Here we report the development of an all solid Mie lidar system using a diode-pumped Nd:YAG laser and a Si-APD detector. This was constructed as a prototype of a handy lidar system.

Ozone Measurements with the US EPA UV-DIAL: Preliminary Results

NASA Technical Reports Server (NTRS)

Moosmueller, H.; Diebel, D.; Bundy, D. H.; Bristow, M. P.; Alvarez, R. J., II; Kovalev, V. A.; Edmonds, C. M.; Turner, R. M.; Mcelroy, J. L.

1992-01-01

A compact airborne down-looking lidar system was developed at the Environmental Protection Agency in Las Vegas. This differential absorption lidar (DIAL) was designed to simultaneously measure range-resolved concentrations of ozone (O3) and sulfur dioxide (SO2) in the lower troposphere, together with an indication of the aerosol distribution. The five laser wavelengths (i.e., lambda(sub 1) = 277 nm, lambda(sub 2) = 292 nm, lambda(sub 3) = 313 nm, lambda(sub4) = 319 nm, lambda(sub 5) = 369 nm) were generated via Raman conversion of a focused KrF excimer laser. The system is currently installed in a truck-based mobile laboratory. For the ground testing, an opening in the truck floor together with a folding mirror under the truck makes a horizontal, or upwardly inclined direction of measurement possible. Initial ground testing has been performed in the vicinity of a Desert Research Institute (DRI) ambient air monitoring site, located at Cottonwood Cove approximately 85 km south east of Las Vegas, Nevada. At this site O3 and SO2 concentrations are continuously monitored with an average accuracy better than +/- 10 percent. A temporary ozone measurement station with identical accuracy was set up at a distance to get a second point of comparison for the range-resolved DIAL measurements.

The Micro-Pulse Lidar Network (MPLNET): A Federated Network of Micro-pulse Lidars and AERONET Sunphotometers

NASA Technical Reports Server (NTRS)

Welton, Ellsworth J.; Campbell, James R.; Spinhirne, James D.; Berkoff, Timothy A.; Holben, Brent; Tsay, Si-Chee

2004-01-01

We present the formation of a new global-ground based eye-safe lidar network, the NASA Micro-Pulse Lidar Network (MPLNET). The aim of MPLNET is to acquire long- term observations of aerosol and cloud vertical profiles at unique geographic sites within the NASA Aerosol Robotic Network (AERONET). MPLNET utilizes standard instrumentation and data processing algorithms for efficient network operations and direct comparison of data between each site. The micro-pulse lidar is eye-safe, compact, and commercially available, and most easily allows growth of the network without sacrificing standardized instrumentation goals. Network growth follows a federated approach, pioneered by AERONET, wherein independent research groups may join MPLNET with their own instrument and site. MPLNET sites produce not only vertical profile data, but also column-averaged products already available from AERONET (aerosol optical depth, sky radiance, size distributions). Algorithms are presented for each MPLNET data product. Real-time Level 1 data products (next-day) include daily lidar signal images from the surface to -2Okm, and Level 1.5 aerosol extinction profiles at times co-incident with AERONET observations. Quality assured Level 2 aerosol extinction profiles are generated after screening the Level 1.5 results and removing bad data. Level 3 products include continuous day/night aerosol extinction profiles, and are produced using Level 2 calibration data. Rigorous uncertainty calculations are presented for all data products. Analysis of MPLNET data show the MPL and our analysis routines are capable of successfully retrieving aerosol profiles, with the strenuous accounting of uncertainty necessary for accurate interpretation of the results.

Three-dimensional feature extraction and geometric mappings for improved parameter estimation in forested terrain using airborne LiDAR data

NASA Astrophysics Data System (ADS)

Lee, Heezin

Scanning laser ranging technology is well suited for measuring point-to-point distances because of its ability to generate small beam divergences. As a result, many of the laser pulses emitted from airborne light detection and ranging (LiDAR) systems are able to reach the ground underneath tree canopies through small (10 cm scale) gaps in the foliage. Using high pulse rate lasers and fast optical scanners, airborne LiDAR systems can provide both high spatial resolution and canopy penetration, and these data have become more widely available in recent years for use in environmental and forestry applications. The small-footprint, discrete-return Airborne Laser Swath Mapping (ALSM) system at the University of Florida (UF) is used to directly measure ground surface elevations and the three-dimensional (3D) distribution of the vegetative material above the soil surface. Field of view geometric mappings are explored to find optical gaps inside forests. First, a method is developed to detect walking trails in natural forests that are obscured from above by the canopy. Several features are derived from the ALSM data and used to constrain the search space and infer the location of trails. Second, a robust and simple procedure for estimating intercepted photosynthetically active radiation (IPAR), which is an important measure of forest timber productivity and of daylight visibility in forested terrain, is presented. Simple scope functions that isolate the relevant LiDAR reflections between observer locations and the sun are defined and shown to give good agreement between the LiDAR-derived estimates and values of IPAR measured in situ. A conical scope function with an angular divergence from the centerline of +/-7° provided the best agreement with the in situ measurements. This scope function yielded remarkably consistent IPAR estimates for different pine species and growing conditions. The developed idea could be extended, through potential future work, to characterize the spatial distribution of attenuation of GPS (L-band) microwave signals and of detectability from the sky for military personnel operating in forested terrain. Measuring individual trees can provide valuable information about forests, and airborne LiDAR sensors have been recently used to identify individual trees and measure structural tree parameters. Past results, however, have been mixed because of reliance on interpolated (image) versions of the LiDAR measurements and search methods that do not adapt to variations in canopies. In this work, an adaptive clustering method is developed using 3D airborne LiDAR data acquired over two distinctly different managed pine forests in North-Central Florida, USA. A critical issue in isolating individual trees is determining the appropriate size of the moving window (search radius) when locating seed points. The proposed approach works directly on the 3D "cloud" of LiDAR points and adapts to irregular canopy sizes. The region growing step yields collectively exhaustive sets in an initial segmentation of tree canopies. An agglomerative clustering step is then used to merge clusters that represent parts of whole canopies using the locally varying height distribution. The overall tree detection accuracy achieved is 95.1% with no significant bias. The tree detection enables subsequent estimation of tree height and vertical crown length to an accuracy of better than 0.8 m and 1.5 m, respectively. Lastly, a compact representation of the different geometric characteristics of the segmented LiDAR points is introduced using spin images as a new tool that can potentially help tree detection in complex natural forests.

New single-aircraft integrated atmospheric observation capabilities

NASA Astrophysics Data System (ADS)

Wang, Z.

2011-12-01

Improving current weather and climate model capabilities requires better understandings of many atmospheric processes. Thus, advancing atmospheric observation capabilities has been regarded as the highest imperatives to advance the atmospheric science in the 21st century. Under the NSF CAREER support, we focus on developing new airborne observation capabilities through the developments of new instrumentations and the single-aircraft integration of multiple remote sensors with in situ probes. Two compact Wyoming cloud lidars were built to work together with a 183 GHz microwave radiometer, a multi-beam Wyoming cloud radar and in situ probes for cloud studies. The synergy of these remote sensor measurements allows us to better resolve the vertical structure of cloud microphysical properties and cloud scale dynamics. Together with detailed in situ data for aerosol, cloud, water vapor and dynamics, we developed the most advanced observational capability to study cloud-scale properties and processes from a single aircraft (Fig. 1). A compact Raman lidar was also built to work together with in situ sampling to characterize boundary layer aerosol and water vapor distributions for many important atmospheric processes studies, such as, air-sea interaction and convective initialization. Case studies will be presented to illustrate these new observation capabilities.

Continuous-wave sodium D2 resonance radiation generated in single-pass sum-frequency generation with periodically poled lithium niobate.

PubMed

Yue, J; She, C-Y; Williams, B P; Vance, J D; Acott, P E; Kawahara, T D

2009-04-01

With two cw single-mode Nd:YAG lasers at 1064 and 1319 nm and a periodically poled lithium niobate crystal, 11 mW of 2 kHz/100 ms bandwidth single-mode tunable 589 nm cw radiation has been detected using single-pass sum-frequency generation. The demonstrated conversion efficiency is approximately 3.2%[W(-1) cm(-1)]. This compact solid-state light source has been used in a solid-state-dye laser hybrid sodium fluorescence lidar transmitter to measure temperatures and winds in the upper atmosphere (80-105 km); it is being implemented into the transmitter of a mobile all-solid-state sodium temperature and wind lidar under construction.

1540-nm single frequency single-mode pulsed all fiber laser for coherent Doppler lidar

NASA Astrophysics Data System (ADS)

Zhang, Xin; Diao, Weifeng; Liu, Yuan; Liu, Jiqiao; Hou, Xia; Chen, Weibiao

2015-02-01

A single-mode single frequency eye-safe pulsed all fiber laser based on master oscillator power amplification structure is presented. This laser is composed of a narrow linewidth distributed laser diode seed laser and two-stage cascade amplifiers. 0.8 m longitudinally gradient strained erbium/ytterbium co-doped polarization-maintaining fiber with a core diameter of 10 μm is used as the gain fiber and two acoustic-optics modulators are adopted to enhance pulse extinction ratio. A peak power of 160 W and a pulse width of 200 ns at 10 kHz repetition rate are achieved with transform-limited linewidth and diffraction-limited beam quality. This laser will be employed in a compact short range coherent Doppler wind lidar.

Coherent Lidar Turbulence Measurement for Gust Load Alleviation

NASA Technical Reports Server (NTRS)

Bogue, Rodney K.; Ehernberger, L. J.; Soreide, David; Bagley, Hal

1996-01-01

Atmospheric turbulence adversely affects operation of commercial and military aircraft and is a design constraint. The airplane structure must be designed to survive the loads imposed by turbulence. Reducing these loads allows the airplane structure to be lighter, a substantial advantage for a commercial airplane. Gust alleviation systems based on accelerometers mounted in the airplane can reduce the maximum gust loads by a small fraction. These systems still represent an economic advantage. The ability to reduce the gust load increases tremendously if the turbulent gust can be measured before the airplane encounters it. A lidar system can make measurements of turbulent gusts ahead of the airplane, and the NASA Airborne Coherent Lidar for Advanced In-Flight Measurements (ACLAIM) program is developing such a lidar. The ACLAIM program is intended to develop a prototype lidar system for use in feasibility testing of gust load alleviation systems and other airborne lidar applications, to define applications of lidar with the potential for improving airplane performance, and to determine the feasibility and benefits of these applications. This paper gives an overview of the ACLAIM program, describes the lidar architecture for a gust alleviation system, and describes the prototype ACLAIM lidar system.

Development of a Coherent Lidar for Aiding Precision Soft Landing on Planetary Bodies

NASA Technical Reports Server (NTRS)

Amzajerdian, Farzin; Pierrottet, Diego; Tolson, Robert H.; Powell, Richard W.; Davidson, John B.; Peri, Frank

2005-01-01

Coherent lidar can play a critical role in future planetary exploration missions by providing key guidance, navigation, and control (GNC) data necessary for navigating planetary landers to the pre-selected site and achieving autonomous safe soft-landing. Although the landing accuracy has steadily improved over time to approximately 35 km for the recent Mars Exploration Rovers due to better approach navigation, a drastically different guidance, navigation and control concept is required to meet future mission requirements. For example, future rovers will require better than 6 km landing accuracy for Mars and better than 1 km for the Moon plus maneuvering capability to avoid hazardous terrain features. For this purpose, an all-fiber coherent lidar is being developed to address the call for advancement of entry, descent, and landing technologies. This lidar will be capable of providing precision range to the ground and approach velocity data, and in the case of landing on Mars, it will also measure the atmospheric wind and density. The lidar obtains high resolution range information from a frequency modulated-continuous wave (FM-CW) laser beam whose instantaneous frequency varies linearly with time, and the ground vector velocity is directly extracted from the Doppler frequency shift. Utilizing the high concentration of aerosols in the Mars atmosphere (approx. two order of magnitude higher than the Earth), the lidar can measure wind velocity with a few watts of optical power. Operating in 1.57 micron wavelength regime, the lidar can use the differential absorption (DIAL) technique to measure the average CO2 concentration along the laser beam using, that is directly proportional to the Martian atmospheric density. Employing fiber optics components allows for the lidar multi-functional operation while facilitating a highly efficient, compact and reliable design suitable for integration into a spacecraft with limited mass, size, and power resources.

Lidar instruments proposed for Eos

NASA Technical Reports Server (NTRS)

Grant, William B.; Browell, Edward V.

1990-01-01

Lidar, an acronym for light detection and ranging, represents a class of instruments that utilize lasers to send probe beams into the atmosphere or onto the surface of the Earth and detect the backscattered return in order to measure properties of the atmosphere or surface. The associated technology has matured to the point where two lidar facilities, Geodynamics Laser Ranging System (GLRS), and Laser Atmospheric Wind Sensor (LAWS) were accepted for Phase 2 studies for Eos. A third lidar facility Laser Atmospheric Sounder and Altimeter (LASA), with the lidar experiment EAGLE (Eos Atmospheric Global Lidar Experiment) was proposed for Eos. The generic lidar system has a number of components. They include controlling electronics, laser transmitters, collimating optics, a receiving telescope, spectral filters, detectors, signal chain electronics, and a data system. Lidar systems that measure atmospheric constituents or meteorological parameters record the signal versus time as the beam propagates through the atmosphere. The backscatter arises from molecular (Rayleigh) and aerosol (Mie) scattering, while attenuation arises from molecular and aerosol scattering and absorption. Lidar systems that measure distance to the Earth's surface or retroreflectors in a ranging mode record signals with high temporal resolution over a short time period. The overall characteristics and measurements objectives of the three lidar systems proposed for Eos are given.

The design, development, and test of balloonborne and groundbased lidar systems. Volume 1: Balloonborne coherent CO2 lidar system

NASA Astrophysics Data System (ADS)

Shepherd, O.; Aurilio, G.; Bucknam, R. D.; Hurd, A. G.; Rappaport, S. A.

1991-06-01

This is Volume 1 of a three volume final report on the design, development, and test of balloonborne and groundbased lidar systems. Volume 2 describes the flight test of Atmospheric Balloonborne Lidar Experiment, ABLE 2, which successfully made atmospheric density backscatter measurements during a flight over White Sands Missile Range. Volume 3 describes groundbased lidar development and measurements, including the design of a telescope dome lidar installation, the design of a transportable lidar shed for remote field sites, and field measurements of atmospheric and cloud backscatter from Ascension Island during SABLE 89 and Terciera, Azores during GABLE 90. In this volume, Volume 1, the design and fabrication of a balloonborne CO2 coherent lidar payload are described. The purpose of this payload is to measure, from altitudes greater than 20 km, the 10.6 micrometers backscatter from atmospheric aerosols as a function of altitude. Minor modifications to the lidar would provide for aerosol velocity measurements to be made. The lidar and payload system design was completed, and major components were fabricated and assembled. These tasks have been successfully completed, and recommendations for further lidar measurements and data analysis have been made.

Compact Ozone Differential Absorption Lidar (DIAL) Transmitter Using Solid-State Dye Polymers

NASA Technical Reports Server (NTRS)

Jones, Alton L., Jr.; DeYoung, Russell J.; Elsayid-Ele, Hani

2001-01-01

A new potential DIAL laser transmitter is described that uses solid-state dye laser materials to make a simpler, more compact, lower mass laser system. Two solid-state dye laser materials were tested to evaluate their performance in a laser oscillator cavity end pumped by a pulsed Nd:YAG laser at 532 nm. The polymer host polymethyl-methacrylate was injected with a pyrromethene laser dye, PM 580, or PM 597. A narrowband laser oscillator cavity was constructed to produce visible wavelengths of 578 and 600 nm which were frequency doubled into the UV region (299 or 300 nm) by using a BBO crystal, resulting in a maximum energy of 11 mJ at a wavelength of 578 nm when pumped by the Nd:YAG laser at an energy of 100 mJ (532 nm). A maximum output energy of 378 microJ was achieved in the UV region at a wavelength of 289 nm but lasted only 2000 laser shots at a repetition rate of 10 Hz. The results are promising and show that a solid-state dye laser based ozone DIAL system is possible with improvements in the design of the laser transmitter.

An Improved Calibration Method for a Rotating 2D LIDAR System.

PubMed

Zeng, Yadan; Yu, Heng; Dai, Houde; Song, Shuang; Lin, Mingqiang; Sun, Bo; Jiang, Wei; Meng, Max Q-H

2018-02-07

This paper presents an improved calibration method of a rotating two-dimensional light detection and ranging (R2D-LIDAR) system, which can obtain the 3D scanning map of the surroundings. The proposed R2D-LIDAR system, composed of a 2D LIDAR and a rotating unit, is pervasively used in the field of robotics owing to its low cost and dense scanning data. Nevertheless, the R2D-LIDAR system must be calibrated before building the geometric model because there are assembled deviation and abrasion between the 2D LIDAR and the rotating unit. Hence, the calibration procedures should contain both the adjustment between the two devices and the bias of 2D LIDAR itself. The main purpose of this work is to resolve the 2D LIDAR bias issue with a flat plane based on the Levenberg-Marquardt (LM) algorithm. Experimental results for the calibration of the R2D-LIDAR system prove the reliability of this strategy to accurately estimate sensor offsets with the error range from -15 mm to 15 mm for the performance of capturing scans.

An Improved Calibration Method for a Rotating 2D LIDAR System

PubMed Central

Zeng, Yadan; Yu, Heng; Song, Shuang; Lin, Mingqiang; Sun, Bo; Jiang, Wei; Meng, Max Q.-H.

2018-01-01

This paper presents an improved calibration method of a rotating two-dimensional light detection and ranging (R2D-LIDAR) system, which can obtain the 3D scanning map of the surroundings. The proposed R2D-LIDAR system, composed of a 2D LIDAR and a rotating unit, is pervasively used in the field of robotics owing to its low cost and dense scanning data. Nevertheless, the R2D-LIDAR system must be calibrated before building the geometric model because there are assembled deviation and abrasion between the 2D LIDAR and the rotating unit. Hence, the calibration procedures should contain both the adjustment between the two devices and the bias of 2D LIDAR itself. The main purpose of this work is to resolve the 2D LIDAR bias issue with a flat plane based on the Levenberg–Marquardt (LM) algorithm. Experimental results for the calibration of the R2D-LIDAR system prove the reliability of this strategy to accurately estimate sensor offsets with the error range from −15 mm to 15 mm for the performance of capturing scans. PMID:29414885

Research and development of commercial lidar systems in romania: critical review of the ESYRO lidar systems developed by sc enviroscopy SRL (ESYRO)

NASA Astrophysics Data System (ADS)

Mihai Cazacu, Marius; Tudose, Ovidiu; Balanici, Dragos; Balin, Ioan

2018-04-01

This paper is shortly presenting the two basic lidar system configurations respectively a micro-lidar and a multi-wavelength lidar systems developed by SC EnviroScopY SRL (ESYRO) from Iasi - Romania in the last decade. Furthermore in addition to the comparative analysis of the two technical configurations the examples of various tests and the capability of the two systems to perform are here presented. Measurements samples of aerosols, clouds, PBL, depolarization and Saharan dust are also illustrated.

Automated Mounting Bias Calibration for Airborne LIDAR System

NASA Astrophysics Data System (ADS)

Zhang, J.; Jiang, W.; Jiang, S.

2012-07-01

Mounting bias is the major error source of Airborne LIDAR system. In this paper, an automated calibration method for estimating LIDAR system mounting parameters is introduced. LIDAR direct geo-referencing model is used to calculate systematic errors. Due to LIDAR footprints discretely sampled, the real corresponding laser points are hardly existence among different strips. The traditional corresponding point methodology does not seem to apply to LIDAR strip registration. We proposed a Virtual Corresponding Point Model to resolve the corresponding problem among discrete laser points. Each VCPM contains a corresponding point and three real laser footprints. Two rules are defined to calculate tie point coordinate from real laser footprints. The Scale Invariant Feature Transform (SIFT) is used to extract corresponding points in LIDAR strips, and the automatic flow of LIDAR system calibration based on VCPM is detailed described. The practical examples illustrate the feasibility and effectiveness of the proposed calibration method.

Space-Based Lidar Systems

NASA Technical Reports Server (NTRS)

Sun, Xiaoli

2012-01-01

An overview of space-based lidar systems is presented. from the first laser altimeter on APOLLO 15 mission in 1971 to the Mercury Laser Altimeter on MESSENGER mission currently in orbit, and those currently under development. Lidar, which stands for Light Detection And Ranging, is a powerful tool in remote sensing from space. Compared to radars, lidars operate at a much shorter wavelength with a much narrower beam and much smaller transmitter and receiver. Compared to passive remote sensing instruments. lidars carry their own light sources and can continue measuring day and night. and over polar regions. There are mainly two types of lidars depending on the types of measurements. lidars that are designed to measure the distance and properties of hard targets are often called laser rangers or laser altimeters. They are used to obtain the surface elevation and global shape of a planet from the laser pulse time-of-night and the spacecraft orbit position. lidars that are designed to measure the backscattering and absorption of a volume scatter, such as clouds and aerosols, are often just called lidars and categorized by their measurements. such as cloud and aerosol lidar, wind lidar, CO2 lidar, and so on. The advantages of space-based lidar systems over ground based lidars are the abilities of global coverage and continuous measurements.

Proceedings of the 20th Annual Conference on Atmospheric Transmission Models, 10-12 June 1997

DTIC Science & Technology

1998-05-21

which models multi - wavelength or tunable system performance over slant paths in the atmosphere. Both hard target and aerosol LIDAR systems may be... extinction due to aerosols is a Raman lidar. Raman lidars also have the capability to measure atmospheric temperature and humidity. The lidars we...ozone absorption. The present lidar system provides extinction measurements at UV and visible wavelengths. The tech- nique has been verified over a

Nineteenth International Laser Radar Conference. Part 2

NASA Technical Reports Server (NTRS)

Singh, Upendra N. (Editor); Ismail, Syed (Editor); Schwemmer, Geary K. (Editor)

1998-01-01

This publication contains extended abstracts of papers presented at the Nineteenth International Laser Radar Conference, held at Annapolis, Maryland, July 6-10, 1998; 260 papers were presented in both oral and poster sessions. The topics of the conference sessions were Aerosol Clouds, Multiple Scattering; Tropospheric Profiling, Stratospheric/Mesospheric Profiling; Wind Profiling; New Lidar Technology and Techniques; Lidar Applications, Including Altimetry and Marine; Space and Future Lidar; and Lidar Commercialization/Eye Safety. This conference reflects the breadth of research activities being conducted in the lidar field. These abstracts address subjects from lidar-based atmospheric investigations, development of new lasers and lidar system technology, and current and future space-based lidar systems.

Nineteenth International Laser Radar Conference. Part 1

NASA Technical Reports Server (NTRS)

Singh, Upendra N. (Editor); Ismail, Syed (Editor); Schwemmer, Geary K. (Editor)

1998-01-01

This publication contains extended abstracts of papers presented at the Nineteenth International Laser Radar Conference, held at Annapolis, Maryland, July 6-10, 1998; 260 papers were presented in both oral and poster sessions. The topics of the conference sessions were Aerosol Clouds, Multiple Scattering; Tropospheric Profiling; Stratospheric/Mesospheric Profiling; Wind Profiling; New Lidar Technology and Techniques; Lidar Applications, including Altimetry and Marine; Space and Future Lidar; and Lidar Commercialization/Eye Safety. This conference reflects the breadth of research activities being conducted in the lidar field. These abstracts address subjects from lidar-based atmospheric investigations, development of new lasers and lidar system technology, and current and future space-based lidar systems.

Assessment of capabilities of lidar systems in day-and night-time under different atmospheric and internal-noise conditions

NASA Astrophysics Data System (ADS)

Agishev, Ravil; Comerón, Adolfo

2018-04-01

As an application of the dimensionless parameterization concept proposed earlier for the characterization of lidar systems, the universal assessment of lidar capabilities in day and night conditions is considered. The dimensionless parameters encapsulate the atmospheric conditions, the lidar optical and optoelectronic characteristics, including the photodetector internal noise, and the sky background radiation. Approaches to ensure immunity of the lidar system to external background radiation are discussed.

Lidar as a Diagnostic of Smoke/Obscurants: Overview and Assessment of the Development with Recommendations

DTIC Science & Technology

1984-10-03

aerosol , and the name " laser radar" is used to denote systems de- signed for the detection of solid objects...34* MEASUREMENW OF T(Li) BY SEPARATE TRANSMISSOMETER . One method of measuring * T(Li) is by a separate transmissometer system operating at the lidar wavelength... transmissometer path may be radially outward from the lidar (along the lidar beam) to save the expense of scanning hardware in a developing lidar system ,

Double-Pulsed 2-Micrometer Lidar Validation for Atmospheric CO2 Measurements

NASA Technical Reports Server (NTRS)

Singh, Upendra N.; Refaat, Tamer F.; Yu, Jirong; Petros, Mulugeta; Remus, Ruben

2015-01-01

A double-pulsed, 2-micron Integrated Path Differential Absorption (IPDA) lidar instrument for atmospheric carbon dioxide (CO2) measurements is successfully developed at NASA Langley Research Center (LaRC). Based on direct detection technique, the instrument can be operated on ground or onboard a small aircraft. Key features of this compact, rugged and reliable IPDA lidar includes high transmitted laser energy, wavelength tuning, switching and locking, and sensitive detection. As a proof of concept, the IPDA ground and airborne CO2 measurement and validation will be presented. IPDA lidar CO2 measurements ground validation were conducted at NASA LaRC using hard targets and a calibrated in-situ sensor. Airborne validation, conducted onboard the NASA B-200 aircraft, included CO2 plum detection from power stations incinerators, comparison to in-flight CO2 in-situ sensor and comparison to air sampling at different altitude conducted by NOAA at the same site. Airborne measurements, spanning for 20 hours, were obtained from different target conditions. Ground targets included soil, vegetation, sand, snow and ocean. In addition, cloud slicing was examined over the ocean. These flight validations were conducted at different altitudes, up to 7 km, with different wavelength controlled weighing functions. CO2 measurement results agree with modeling conducted through the different sensors, as will be discussed.

Highly sensitive lidar with a thumb-sized sensor-head built using an optical fiber preamplifier

NASA Astrophysics Data System (ADS)

Inoue, Daisuke; Ichikawa, Tadashi; Matsubara, Hiroyuki; Mao, Xueon; Maeda, Mitsutoshi; Nagashima, Chie; Kagami, Manabu

2011-06-01

We developed a LIDAR system with a sensor head as small as 22 cc, in spite of the inclusion of a scanning mechanism. This LIDAR system not only has a small body, but is also highly sensitive. Our LIDAR system is based on time-of-flight measurements, and it incorporates an optical fiber. The main feature of our system is the utilization of optical amplifiers for both the transmitter and the receiver, and the optical amplifiers enabled us to exceed the detection limit of thermal noise. In conventional LIDAR systems the detection limit is determined by thermal noise, because the avalanche photo-diodes (APD) and trans-impedance amplifiers (TIA) that they use detect the received signals directly. In the case of our LIDAR system, received signal is amplified by an optical fiber amplifier in front of the photo diode and the TIA. Therefore, our LIDAR system can boost the signal level before the weak incoming signal is depleted by thermal noise. There are conditions under which the noise figure for the combination of an optical fiber amplifier and a photo diode is superior to the noise figure for an avalanche photo diode. We optimized the gain of the optical fiber amplifier and TIA in our LIDAR system such that it is capable of detecting a single photon. As a result, the detection limit of our LIDAR system is determined by shot noise. This small and highly sensitive measurement technology shows great potential for use in LIDAR with an optical preamplifier.

Analysis of 3D Scan Measurement Distribution with Application to a Multi-Beam Lidar on a Rotating Platform.

PubMed

Morales, Jesús; Plaza-Leiva, Victoria; Mandow, Anthony; Gomez-Ruiz, Jose Antonio; Serón, Javier; García-Cerezo, Alfonso

2018-01-30

Multi-beam lidar (MBL) rangefinders are becoming increasingly compact, light, and accessible 3D sensors, but they offer limited vertical resolution and field of view. The addition of a degree-of-freedom to build a rotating multi-beam lidar (RMBL) has the potential to become a common solution for affordable rapid full-3D high resolution scans. However, the overlapping of multiple-beams caused by rotation yields scanning patterns that are more complex than in rotating single beam lidar (RSBL). In this paper, we propose a simulation-based methodology to analyze 3D scanning patterns which is applied to investigate the scan measurement distribution produced by the RMBL configuration. With this purpose, novel contributions include: (i) the adaption of a recent spherical reformulation of Ripley's K function to assess 3D sensor data distribution on a hollow sphere simulation; (ii) a comparison, both qualitative and quantitative, between scan patterns produced by an ideal RMBL based on a Velodyne VLP-16 (Puck) and those of other 3D scan alternatives (i.e., rotating 2D lidar and MBL); and (iii) a new RMBL implementation consisting of a portable tilting platform for VLP-16 scanners, which is presented as a case study for measurement distribution analysis as well as for the discussion of actual scans from representative environments. Results indicate that despite the particular sampling patterns given by a RMBL, its homogeneity even improves that of an equivalent RSBL.

Analysis of 3D Scan Measurement Distribution with Application to a Multi-Beam Lidar on a Rotating Platform

PubMed Central

Plaza-Leiva, Victoria; Serón, Javier

2018-01-01

Multi-beam lidar (MBL) rangefinders are becoming increasingly compact, light, and accessible 3D sensors, but they offer limited vertical resolution and field of view. The addition of a degree-of-freedom to build a rotating multi-beam lidar (RMBL) has the potential to become a common solution for affordable rapid full-3D high resolution scans. However, the overlapping of multiple-beams caused by rotation yields scanning patterns that are more complex than in rotating single beam lidar (RSBL). In this paper, we propose a simulation-based methodology to analyze 3D scanning patterns which is applied to investigate the scan measurement distribution produced by the RMBL configuration. With this purpose, novel contributions include: (i) the adaption of a recent spherical reformulation of Ripley’s K function to assess 3D sensor data distribution on a hollow sphere simulation; (ii) a comparison, both qualitative and quantitative, between scan patterns produced by an ideal RMBL based on a Velodyne VLP-16 (Puck) and those of other 3D scan alternatives (i.e., rotating 2D lidar and MBL); and (iii) a new RMBL implementation consisting of a portable tilting platform for VLP-16 scanners, which is presented as a case study for measurement distribution analysis as well as for the discussion of actual scans from representative environments. Results indicate that despite the particular sampling patterns given by a RMBL, its homogeneity even improves that of an equivalent RSBL. PMID:29385705

Imaging lidar technology: development of a 3D-lidar elegant breadboard for rendezvous and docking, test results, and prospect to future sensor application

NASA Astrophysics Data System (ADS)

Moebius, B.; Pfennigbauer, M.; Pereira do Carmo, J.

2017-11-01

During the previous 15 years, Rendezvous and Docking Sensors (RVS) were developed, manufactured and qualified. In the mean time they were successfully applied in some space missions: For automatic docking of the European ATV "Jules Verne" on the International Space Station in 2008; for automatic berthing of the first Japanese HTV in 2009, and even the precursor model ARP-RVS for measurements during Shuttle Atlantis flights STS-84 and STS-86 to the MIR station. Up to now, about twenty RVS Flight Models for application on ATV, HTV and the American Cygnus Spacecraft were manufactured and delivered to the respective customers. RVS is designed for tracking of customer specific, cooperative targets (i.e. retro reflectors that are arranged in specific geometries). Once RVS has acquired the target, the sensor measures the distance to the target by timeof- flight determination of a pulsed laser beam. Any echo return provokes an interrupt signal and thus the readout of the according encoder positions of the two scan mirrors that represent Azimuth and Elevation measurement direction to the target. [2], [3]. The capability of the RVS for 3D mapping of the scene makes the fully space qualified RVS to be real 3D Lidar sensors; thus they are a sound technical base for the compact 3D Lidar breadboard that was developed in the course of the Imaging Lidar Technology (ILT) project.

Development and Experimental Verification of a High Resolution, Tunable LIDAR Computer Simulation Model for Atmospheric Laser Remote Sensing

NASA Astrophysics Data System (ADS)

Wilcox, William Edward, Jr.

1995-01-01

A computer program (LIDAR-PC) and associated atmospheric spectral databases have been developed which accurately simulate the laser remote sensing of the atmosphere and the system performance of a direct-detection Lidar or tunable Differential Absorption Lidar (DIAL) system. This simulation program allows, for the first time, the use of several different large atmospheric spectral databases to be coupled with Lidar parameter simulations on the same computer platform to provide a real-time, interactive, and easy to use design tool for atmospheric Lidar simulation and modeling. LIDAR -PC has been used for a range of different Lidar simulations and compared to experimental Lidar data. In general, the simulations agreed very well with the experimental measurements. In addition, the simulation offered, for the first time, the analysis and comparison of experimental Lidar data to easily determine the range-resolved attenuation coefficient of the atmosphere and the effect of telescope overlap factor. The software and databases operate on an IBM-PC or compatible computer platform, and thus are very useful to the research community for Lidar analysis. The complete Lidar and atmospheric spectral transmission modeling program uses the HITRAN database for high-resolution molecular absorption lines of the atmosphere, the BACKSCAT/LOWTRAN computer databases and models for the effects of aerosol and cloud backscatter and attenuation, and the range-resolved Lidar equation. The program can calculate the Lidar backscattered signal-to-noise for a slant path geometry from space and simulate the effect of high resolution, tunable, single frequency, and moderate line width lasers on the Lidar/DIAL signal. The program was used to model and analyze the experimental Lidar data obtained from several measurements. A fixed wavelength, Ho:YSGG aerosol Lidar (Sugimoto, 1990) developed at USF and a tunable Ho:YSGG DIAL system (Cha, 1991) for measuring atmospheric water vapor at 2.1 μm were analyzed. The simulations agreed very well with the measurements, and also yielded, for the first time, the ability to easily deduce the atmospheric attentuation coefficient, alpha, from the Lidar data. Simulations and analysis of other Lidar measurements included that of a 1.57 mu m OPO aerosol Lidar system developed at USF (Harrell, 1995) and of the NASA LITE (Laser-in-Space Technology Experiment) Lidar recently flown in the Space shuttle. Finally, an extensive series of laboratory experiments were made with the 1.57 μm OPO Lidar system to test calculations of the telescope/laser overlap and the effect of different telescope sizes and designs. The simulations agreed well with the experimental data for the telescope diameter and central obscuration test cases. The LIDAR-PC programs are available on the Internet from the USAF Lidar Home Page Web site, http://www.cas.usf.edu/physics/lidar.html/.

Development of the Wuhan lidar system

NASA Astrophysics Data System (ADS)

Hu, Zhilin; Liu, Yiping; Hu, Xiong; Zeng, Xizhi

1998-08-01

This paper reports new progress of the Wuhan lidar system. At the present time, our lidar works both at nighttime, to measure the sodium layer in menopause region, and at daytime to measure the aerosol in lower atmosphere region. The daytime working lidar system is equipped with a Faraday Anomalous Dispersion Optical Filter (FADOF), working at the Na resonance line (589 nm) and having an ultra-narrow bandwidth of 2 GHz. The daytime system uses this FADOF to obtain the lidar signal from an altitude of 20 km in our primary experiment. We will also report a comparison of the rms velocity measured by MF radar and Na lidar. A 90% confidence in rms velocity has been achieved.

A GUI visualization system for airborne lidar image data to reconstruct 3D city model

NASA Astrophysics Data System (ADS)

Kawata, Yoshiyuki; Koizumi, Kohei

2015-10-01

A visualization toolbox system with graphical user interfaces (GUIs) was developed for the analysis of LiDAR point cloud data, as a compound object oriented widget application in IDL (Interractive Data Language). The main features in our system include file input and output abilities, data conversion capability from ascii formatted LiDAR point cloud data to LiDAR image data whose pixel value corresponds the altitude measured by LiDAR, visualization of 2D/3D images in various processing steps and automatic reconstruction ability of 3D city model. The performance and advantages of our graphical user interface (GUI) visualization system for LiDAR data are demonstrated.

Dimensionless parameterization of lidar for laser remote sensing of the atmosphere and its application to systems with SiPM and PMT detectors.

PubMed

Agishev, Ravil; Comerón, Adolfo; Rodriguez, Alejandro; Sicard, Michaël

2014-05-20

In this paper, we show a renewed approach to the generalized methodology for atmospheric lidar assessment, which uses the dimensionless parameterization as a core component. It is based on a series of our previous works where the problem of universal parameterization over many lidar technologies were described and analyzed from different points of view. The modernized dimensionless parameterization concept applied to relatively new silicon photomultiplier detectors (SiPMs) and traditional photomultiplier (PMT) detectors for remote-sensing instruments allowed predicting the lidar receiver performance with sky background available. The renewed approach can be widely used to evaluate a broad range of lidar system capabilities for a variety of lidar remote-sensing applications as well as to serve as a basis for selection of appropriate lidar system parameters for a specific application. Such a modernized methodology provides a generalized, uniform, and objective approach for evaluation of a broad range of lidar types and systems (aerosol, Raman, DIAL) operating on different targets (backscatter or topographic) and under intense sky background conditions. It can be used within the lidar community to compare different lidar instruments.

Two-wavelength backscattering lidar for stand off detection of aerosols

NASA Astrophysics Data System (ADS)

Mierczyk, Zygmunt; Zygmunt, Marek; Gawlikowski, Andrzej; Gietka, Andrzej; Kaszczuk, Miroslawa; Knysak, Piotr; Mlodzianko, Andrzej; Muzal, Michal; Piotrowski, Wiesław; Wojtanowski, Jacek

2008-10-01

Following article presents LIDAR for stand off detection of aerosols which was constructed in Institute of Optoelectronics in Military University of Technology. LIDAR is a DISC type system (DIfferential SCattering) and is based on analysis of backscattering signal for two wavelengths (λ1 = 1064 nm and λ2 = 532 nm) - the first and the second harmonic of Nd:YAG laser. Optical receiving system is consisted of aspherical mirror lens, two additional mirrors and a system of interference filters. In detection system of LIDAR a silicon avalanche photodiode and two different amplifiers were used. Whole system is mounted on a specialized platform designed for possibility of LIDAR scanning movements. LIDAR is computer controlled. The compiled software enables regulation of the scanning platform work, gain control, and control of data processing and acquisition system. In the article main functional elements of LIDAR are shown and typical parameters of system work and construction are presented. One presented also first results of research with use of LIDAR. The aim of research was to detect and characterize scattering aerosol, both natural and anthropogenic one. For analyses of natural aerosols, cumulus cloud was used. For analyses of anthropogenic aerosols one used three various pyrotechnic mixtures (DM11, M2, M16) which generate smoke of different parameters. All scattering centers were firstly well described and theoretical analyses were conducted. Results of LIDAR research were compared with theoretical analyses and general conclusions concerning correctness of LIDAR work and its application were drawn.

Powerful Raman Lidar systems for atmospheric analysis and high-energy physics experiments

NASA Astrophysics Data System (ADS)

Avdikos, George

2015-03-01

In this paper the author presents modern commercial Raman Lidar systems which can be applied to high-energy physics experiments. Raymetrics is a world-leader in laser remote (lidar) sensing applications. Products series include lidar systems for various applications like atmospheric analysis, meteorology, and recently more operational applications including volcanic ash detection systems, visual rangers for application to airports etc.

New generation lidar systems for eye safe full time observations

NASA Technical Reports Server (NTRS)

Spinhirne, James D.

1995-01-01

The traditional lidar over the last thirty years has typically been a big pulse low repetition rate system. Pulse energies are in the 0.1 to 1.0 J range and repetition rates from 0.1 to 10 Hz. While such systems have proven to be good research tools, they have a number of limitations that prevent them from moving beyond lidar research to operational, application oriented instruments. These problems include a lack of eye safety, very low efficiency, poor reliability, lack of ruggedness and high development and operating costs. Recent advances in solid state laser, detectors and data systems have enabled the development of a new generation of lidar technology that meets the need for routine, application oriented instruments. In this paper the new approaches to operational lidar systems will be discussed. Micro pulse lidar (MPL) systems are currently in use, and their technology is highlighted. The basis and current development of continuous wave (CW) lidar and potential of other technical approaches is presented.

ATHLI16: the ATHens Lidar Intercomparison campaign

NASA Astrophysics Data System (ADS)

Amodeo, Aldo; D'Amico, Giuseppe; Giunta, Aldo; Papagiannopoulos, Nikolaos; Papayannis, Alex; Argyrouli, Athina; Mylonaki, Maria; Tsaknakis, Georgios; Kokkalis, Panos; Soupiona, Ourania; Tzanis, Chris

2018-04-01

The results of the ATHLI16 (ATHens Lidar Intercomparison) campaign, held in Athens from 26/09 to 07/10 2016 are presented. The campaign was performed within the Lidar Calibration Centre activities (EU H2020 ACTRIS-2 project) to assess the performance of the EOLE lidar system (NTUA, Athens, Greece), operating within EARLINET, by comparing against the EARLINET reference lidar system MUSA (CNR-IMAA, Potenza, Italy). For both lidars only products retrieved by the EARLINET Single Calculus Chain have been compared.

Differential absorption and Raman lidar for water vapor profile measurements - A review

NASA Technical Reports Server (NTRS)

Grant, William B.

1991-01-01

Differential absorption lidar and Raman lidar have been applied to the range-resolved measurements of water vapor density for more than 20 years. Results have been obtained using both lidar techniques that have led to improved understanding of water vapor distributions in the atmosphere. This paper reviews the theory of the measurements, including the sources of systematic and random error; the progress in lidar technology and techniques during that period, including a brief look at some of the lidar systems in development or proposed; and the steps being taken to improve such lidar systems.

Shipborne LiDAR system for coastal change monitoring

NASA Astrophysics Data System (ADS)

Kim, chang hwan; Park, chang hong; Kim, hyun wook; hyuck Kim, won; Lee, myoung hoon; Park, hyeon yeong

2016-04-01

Coastal areas, used as human utilization areas like leisure space, medical care, ports and power plants, etc., are regions that are continuously changing and interconnected with oceans and land and the sea level has risen by about 8cm (1.9mm / yr) due to global warming from 1964 year to 2006 year in Korea. Coastal erosion due to sea-level rise has caused the problem of marine ecosystems and loss of tourism resources, etc. Regular monitoring of coastal erosion is essential at key locations with such volatility. But the survey method of land mobile LiDAR (light detection and ranging) system has much time consuming and many restrictions. For effective monitoring beach erosion, KIOST (Korea Institute of Ocean Science & Technology) has constructed a shipborne mobile LiDAR system. The shipborne mobile LiDAR system comprised a land mobile LiDAR (RIEGL LMS-420i), an INS (inertial navigation system, MAGUS Inertial+), a RTKGPS (LEICA GS15 GS25), and a fixed platform. The shipborne mobile LiDAR system is much more effective than a land mobile LiDAR system in the measuring of fore shore areas without shadow zone. Because the vessel with the shipborne mobile LiDAR system is continuously moved along the shoreline, it is possible to efficiently survey a large area in a relatively short time. Effective monitoring of the changes using the constructed shipborne mobile LiDAR system for seriously eroded coastal areas will be able to contribute to coastal erosion management and response.

Scientist's Idealism Vs. User's Realism for Orthorectification of Full Radarsat-2/Compact RCM Polarimetric Data with DSM

NASA Astrophysics Data System (ADS)

Toutin, Thierry; Wang, Huili; Charbonneau, Francois; Schmitt, Carla

2013-08-01

This paper presented two methods for the orthorectification of full/compact polarimetric SAR data: the polarimetric processing is performed in the image space (scientist's idealism) or in the ground space (user's realism) before or after the geometric processing, respectively. Radarsat-2 (R2) fine-quad and simulated very high-resolution RCM data acquired with different look angles over a hilly relief study site were processed using accurate lidar digital surface model. Quantitative evaluations between the two methods as a function of different geometric and radiometric parameters were performed to evaluate the impact during the orthorectification. The results demonstrated that the ground-space method can be safely applied to polarimetric R2 SAR data with an exception with the steep look angles and steep terrain slopes. On the other hand, the ground-space method cannot be applied to simulated compact RCM data due to 17dB noise floor and oversampling.

A digital signal processing system for coherent laser radar

NASA Technical Reports Server (NTRS)

Hampton, Diana M.; Jones, William D.; Rothermel, Jeffry

1991-01-01

A data processing system for use with continuous-wave lidar is described in terms of its configuration and performance during the second survey mission of NASA'a Global Backscatter Experiment. The system is designed to estimate a complete lidar spectrum in real time, record the data from two lidars, and monitor variables related to the lidar operating environment. The PC-based system includes a transient capture board, a digital-signal processing (DSP) board, and a low-speed data-acquisition board. Both unprocessed and processed lidar spectrum data are monitored in real time, and the results are compared to those of a previous non-DSP-based system. Because the DSP-based system is digital it is slower than the surface-acoustic-wave signal processor and collects 2500 spectra/s. However, the DSP-based system provides complete data sets at two wavelengths from the continuous-wave lidars.

Gluing for Raman lidar systems using the lamp mapping technique.

PubMed

Walker, Monique; Venable, Demetrius; Whiteman, David N

2014-12-20

In the context of combined analog and photon counting (PC) data acquisition in a Lidar system, glue coefficients are defined as constants used for converting an analog signal into a virtual PC signal. The coefficients are typically calculated using Lidar profile data taken under clear, nighttime conditions since, in the presence of clouds or high solar background, it is difficult to obtain accurate glue coefficients from Lidar backscattered data. Here we introduce a new method in which we use the lamp mapping technique (LMT) to determine glue coefficients in a manner that does not require atmospheric profiles to be acquired and permits accurate glue coefficients to be calculated when adequate Lidar profile data are not available. The LMT involves scanning a halogen lamp over the aperture of a Lidar receiver telescope such that the optical efficiency of the entire detection system is characterized. The studies shown here involve two Raman lidar systems; the first from Howard University and the second from NASA/Goddard Space Flight Center. The glue coefficients determined using the LMT and the Lidar backscattered method agreed within 1.2% for the water vapor channel and within 2.5% for the nitrogen channel for both Lidar systems. We believe this to be the first instance of the use of laboratory techniques for determining the glue coefficients for Lidar data analysis.

Development of a high-speed wavelength-agile CO2 local oscillator for heterodyne DIAL measurements

NASA Astrophysics Data System (ADS)

Senft, Daniel C.; Pierrottet, Diego F.

2002-06-01

A high repetition rate, wavelength agile CO2 laser has been developed at the Air Force Research Laboratory for use as a local oscillator in a heterodyne detection receiver. Fats wavelength selection is required for measurements of airborne chemical vapors using the differential absorption lidar (DIAL) technique. Acousto-optic modulator are used to tune between different wavelengths at high speeds without the need for moving mechanical parts. Other advantages obtained by the use of acousto-optic modulators are laser output power control per wavelength and rugged packaging for field applications. The local oscillator design is described, and the results from laboratory DIAL measurements are presented. The coherent remote optical sensor system is an internal research project being conducted by the Air Force Research Laboratory Directed Energy Directorate, Active Remote Sensing Branch. The objective of the project is to develop a new long-range standoff spectral sensor that takes advantage of the enhanced performance capabilities coherent detection can provide. Emphasis of the development is on a low cost, compact, and rugged active sensor exclusively designed for heterodyne detection using the differential absorption lidar technique. State of the art technologies in waveguide laser construction and acousto- optics make feasible the next generation of lasers capable of supporting coherent lidar system requirements. Issues addressed as part of the development include optoelectronic engineering of a low cost rugged system, and fast data throughput for real time chemical concentration measurements. All hardware used in this sensor are off-the- shelf items, so only minor hardware modifications were required for the system as it stands. This paper describes a high-speed heterodyne detection CO2 DIAL system that employs a wavelength agile, acousto-optically tuned local oscillator in the receiver. Sample experimental data collected in a controlled environment are presented as well. Chemical detection using 12 wavelengths at 200 pulses per second has been demonstrated. Initial progress on experiments to make a direct, simultaneous comparison of heterodyne and direct detection DIAL systems will also be described.

Role of Lidar Technology in Future NASA Space Missions

NASA Technical Reports Server (NTRS)

Amzajerdian, Farzin

2008-01-01

The past success of lidar instruments in space combined with potentials of laser remote sensing techniques in improving measurements traditionally performed by other instrument technologies and in enabling new measurements have expanded the role of lidar technology in future NASA missions. Compared with passive optical and active radar/microwave instruments, lidar systems produce substantially more accurate and precise data without reliance on natural light sources and with much greater spatial resolution. NASA pursues lidar technology not only as science instruments, providing atmospherics and surface topography data of Earth and other solar system bodies, but also as viable guidance and navigation sensors for space vehicles. This paper summarizes the current NASA lidar missions and describes the lidar systems being considered for deployment in space in the near future.

Design and Development of a Scanning Airborne Direct Detection Doppler Lidar System

NASA Technical Reports Server (NTRS)

Gentry, Bruce; McGill, Matthew; Schwemmer, Geary; Hardesty, Michael; Brewer, Alan; Wilkerson, Thomas; Atlas, Robert; Sirota, Marcos; Lindemann, Scott

2006-01-01

In the fall of 2005 we began developing an airborne scanning direct detection molecular Doppler lidar. The instrument is being built as part of the Tropospheric Wind Lidar Technology Experiment (TWiLiTE), a three year project selected by the NASA Earth Sun Technology Office under the Instrument Incubator Program. The TWiLiTE project is a collaboration involving scientists and engineers from NASA Goddard Space Flight Center, NOAA ESRL, Utah State University Space Dynamics Lab, Michigan Aerospace Corporation and Sigma Space Corporation. The TWiLiTE instrument will leverage significant research and development investments made by NASA Goddard and it's partners in the past several years in key lidar technologies and sub-systems (lasers, telescopes, scanning systems, detectors and receivers) required to enable spaceborne global wind lidar measurement. These sub-systems will be integrated into a complete molecular direct detection Doppler wind lidar system designed for autonomous operation on a high altitude aircraft, such as the NASA WB57. The WB57 flies at an altitude of 18 km and from this vantage point the nadir viewing Doppler lidar will be able to profile winds through the full troposphere. The TWiLiTE integrated airborne Doppler lidar instrument will be the first demonstration of a airborne scanning direct detection Doppler lidar and will serve as a critical milestone on the path to a future spaceborne tropospheric wind system. In addition to being a technology testbed for space based tropospheric wind lidar, when completed the TWiLiTE high altitude airborne lidar will be used for studying mesoscale dynamics and storm research (e.g. winter storms, hurricanes) and could be used for calibration and validation of satellite based wind systems such as ESA's Aeolus Atmospheric Dynamics Mission. The TWiLiTE Doppler lidar will have the capability to profile winds in clear air from the aircraft altitude of 18 km to the surface with 250 m vertical resolution and < 2mls velocity accuracy.

Lidar-based estimates of aboveground biomass in the continental US and Mexico using ground, airborne, and satellite observations

Treesearch

Ross Nelson; Hank Margolis; Paul Montesano; Guoqing Sun; Bruce Cook; Larry Corp; Hans-Erik Andersen; Ben deJong; Fernando Paz Pellat; Thaddeus Fickel; Jobriath Kauffman; Stephen Prisley

2017-01-01

Existing national forest inventory plots, an airborne lidar scanning (ALS) system, and a space profiling lidar system (ICESat-GLAS) are used to generate circa 2005 estimates of total aboveground dry biomass (AGB) in forest strata, by state, in the continental United States (CONUS) and Mexico. The airborne lidar is used to link ground observations of AGB to space lidar...

Balloonborne lidar payloads for remote sensing

NASA Astrophysics Data System (ADS)

Shepherd, O.; Aurilio, G.; Hurd, A. G.; Rappaport, S. A.; Reidy, W. P.; Rieder, R. J.; Bedo, D. E.; Swirbalus, R. A.

1994-02-01

A series of lidar experiments has been conducted using the Atmospheric Balloonborne Lidar Experiment payload (ABLE). These experiments included the measurement of atmospheric Rayleigh and Mie backscatter from near space (approximately 30 km) and Raman backscatter measurements of atmospheric constituents as a function of altitude. The ABLE payload consisted of a frequency-tripled Nd:YAG laser transmitter, a 50 cm receiver telescope, and filtered photodetectors in various focal plane configurations. The payload for lidar pointing, thermal control, data handling, and remote control of the lidar system. Comparison of ABLE performance with that of a space lidar shows significant performance advantages and cost effectiveness for balloonborne lidar systems.

New generation of airborne lidar for forest canopy sampling

NASA Astrophysics Data System (ADS)

Cuesta, J.; Chazette, P.; Allouis, T.; Sanak, J.; Genou, P.; Flamant, P. H.; Durrieu, S.; Toussaint, F.

2009-04-01

Cuesta J. (1,2), Chazette P. (1,3), Allouis T. (4), Sanak J. (1,3), Genau P. (2), Flamant P.H. (1), Durrieu S. (4) and Toussaint F. Biomass in forest cover is an essential actor in climate regulation. It is one of the principal sinks of atmospheric CO2 and a major water cycle regulator. In the coming years, climate change may generate an increase in the frequency of fires in the ecosystems, which are already affected in regions as southern Europe, near the Mediterranean basin. For a better understanding and prevention of the risks created by the propagation and intensity of fires, one requires a detailed characterization of the structural parameters of the forest canopy. Such description is as well essential for a proper management and sustainable use of forest resources and the characterization of the evolution of bio-diversity. These environmental and socio-economical issues motivate the development of new remote sensing instruments and methodology, particularly active remote sensing by lidar. These tools should be evaluated in order to achieve a global survey of the forest cover by satellite observation. In this framework, a French effort of the Institut Pierre Simon Laplace (LMD, LSCE and LATMOS) and the CEMAGREF has led to the deployment of a new airborne lidar prototype to study the vertical distribution of the forest canopy in the Landes region in France, around the Arcachon basin and Mimizan. The measuring system is the ultra-violet new generation lidar LAUVA (Lidar Aérosol UtraViolet (Aéroporté), Chazette et al., EST 2007), onboard an Ultra-Light Airplane (ULA). This system was developed by the Comissarait pour l'Energie Atomique and the Centre National de Recherches Scientifiques, originally for atmospheric applications, and it was successfully used in West Africa in the framework of the African Monsoon Multidisciplinary Analyses. After a proper adaptation, this compact and polyvalent lidar onboard an ULA is capable of measuring the forest canopy with an unequal malleability, both in terms of adaptability of instrumental parameters (divergence, field of view, sensitivity, pointing angle) and the flight plan (measuring range and field exploration). The use of a ultra-violet wavelength at 355 nm enables eye-safe emission of energetic laser pulses (16 mJ at 20 Hz). Besides the lidar and geo-referencing instruments, the ULA payload has been completed by two cameras operating at three bands (visible, near infrared and ultra-violet) to retrieve the canopy tri-dimensional structure by stereoscopy. During this experience, the vegetation vertical structure (tree height and crowns, bushes and underbrush) of tree parcels were statistically characterized. A total of three parcels of approximately 500 x 500 m2 composed principally by maritime pines of several ages were sampled following difference experimental configurations. Observations at two flight altitudes at 300 and 500 m were performed, obtaining lidar footprints of 2.4 and 4 m of diameter, respectively. These comparisons will be presented as well as measurements pointing at nadir and 30°. New experiences are planned for 2009 to sample different types of forest cover (leaf and conifers) and optimize the lidar instrument and the associated methodology, in order to achieve a multifunction tool to measure both the forest canopy and the atmospheric components.

The design, development, and test of balloonborne and groundbased lidar systems. Volume 2: Flight test of Atmospheric Balloon Lidar Experiment, ABLE 2

NASA Astrophysics Data System (ADS)

Shepherd, O.; Bucknam, R. D.; Hurd, A. G.; Sheehan, W. H.

1991-06-01

This is Volume 3 of a three volume final report on the design, development, and test of balloonborne and groundbased lidar systems. Volume 1 describes the design and fabrication of a balloonborne CO2 coherent payload to measure the 10.6 micrometers backscatter from atmospheric aerosols as a function of altitude. Volume 2 describes the Aug. 1987 flight test of Atmospheric Balloonborne Lidar Experiment, ABLE 2. In this volume we describe groundbased lidar development and measurements. A design was developed for installation of the ABLE lidar in the GL rooftop dome. A transportable shed was designed to house the ABLE lidar at the various remote measurement sites. Refurbishment and modification of the ABLE lidar were completed to permit groundbased lidar measurements of clouds and aerosols. Lidar field measurements were made at Ascension Island during SABLE 89. Lidar field measurements were made at Terciera, Azores during GABLE 90. These tasks were successfully completed, and recommendations for further lidar measurements and data analysis were made.

Method to determine and adjust the alignment of the transmitter and receiver fields of view of a LIDAR system

DOEpatents

Schmitt, Randal L [Tijeras, NM; Henson, Tammy D [Albuquerque, NM; Krumel, Leslie J [Cedar Crest, NM; Hargis, Jr., Philip J.

2006-06-20

A method to determine the alignment of the transmitter and receiver fields of view of a light detection and ranging (LIDAR) system. This method can be employed to determine the far-field intensity distribution of the transmitter beam, as well as the variations in transmitted laser beam pointing as a function of time, temperature, or other environmental variables that may affect the co-alignment of the LIDAR system components. In order to achieve proper alignment of the transmitter and receiver optical systems when a LIDAR system is being used in the field, this method employs a laser-beam-position-sensing detector as an integral part of the receiver optics of the LIDAR system.

Deriving Leaf Area Index (LAI) from multiple lidar remote sensing systems

NASA Astrophysics Data System (ADS)

Tang, H.; Dubayah, R.; Zhao, F.

2012-12-01

LAI is an important biophysical variable linking biogeochemical cycles of earth systems. Observations with passive optical remote sensing are plagued by saturation and results from different passive and active sensors are often inconsistent. Recently lidar remote sensing has been applied to derive vertical canopy structure including LAI and its vertical profile. In this research we compare LAI retrievals from three different types of lidar sensors. The study areas include the La Selva Biological Station in Costa Rica and Sierra Nevada Forest in California. We first obtain independent LAI estimates from different lidar systems including airborne lidar (LVIS), spaceborne lidar (GLAS) and ground lidar (Echidna). LAI retrievals are then evaluated between sensors as a function of scale, land cover type and sensor characteristics. We also assess the accuracy of these LAI products against ground measurements. By providing a link between ground observations, ground lidar, aircraft and space-based lidar we hope to demonstrate a path for deriving more accurate estimates of LAI on a global basis, and to provide a more robust means of validating passive optical estimates of this important variable.

Automated Feature Extraction of Foredune Morphology from Terrestrial Lidar Data

NASA Astrophysics Data System (ADS)

Spore, N.; Brodie, K. L.; Swann, C.

2014-12-01

Foredune morphology is often described in storm impact prediction models using the elevation of the dune crest and dune toe and compared with maximum runup elevations to categorize the storm impact and predicted responses. However, these parameters do not account for other foredune features that may make them more or less erodible, such as alongshore variations in morphology, vegetation coverage, or compaction. The goal of this work is to identify other descriptive features that can be extracted from terrestrial lidar data that may affect the rate of dune erosion under wave attack. Daily, mobile-terrestrial lidar surveys were conducted during a 6-day nor'easter (Hs = 4 m in 6 m water depth) along 20km of coastline near Duck, North Carolina which encompassed a variety of foredune forms in close proximity to each other. This abstract will focus on the tools developed for the automated extraction of the morphological features from terrestrial lidar data, while the response of the dune will be presented by Brodie and Spore as an accompanying abstract. Raw point cloud data can be dense and is often under-utilized due to time and personnel constraints required for analysis, since many algorithms are not fully automated. In our approach, the point cloud is first projected into a local coordinate system aligned with the coastline, and then bare earth points are interpolated onto a rectilinear 0.5 m grid creating a high resolution digital elevation model. The surface is analyzed by identifying features along each cross-shore transect. Surface curvature is used to identify the position of the dune toe, and then beach and berm morphology is extracted shoreward of the dune toe, and foredune morphology is extracted landward of the dune toe. Changes in, and magnitudes of, cross-shore slope, curvature, and surface roughness are used to describe the foredune face and each cross-shore transect is then classified using its pre-storm morphology for storm-response analysis.

Highly sensitive LIDAR with a thumb-sized sensor-head built using an optical fiber preamplifier (3)

NASA Astrophysics Data System (ADS)

Inoue, Daisuke; Ichikawa, Tadashi; Matsubara, Hiroyuki; Kagami, Manabu

2013-05-01

We have developed a LIDAR system with a sensor head which, although it includes a scanning mechanism, is less than 20 cc in size. The system is not only small, but is also highly sensitive. Our LIDAR system is based on time-of-flight measurements, and incorporates an optical fiber. The main feature of our system is the utilization of optical amplifiers for both the transmitter and the receiver, and the optical amplifiers enable us to exceed the detection limit set by thermal noise. In conventional LIDAR systems the detection limit is determined by the thermal noise, because the avalanche photo-diodes (APD) and trans-impedance amplifiers (TIA) that they use detect the received signals directly. In the case of our LIDAR system, the received signal is amplified by an optical fiber amplifier before reaching the photo diode and the TIA. Therefore, our LIDAR system boosts the signal level before the weak incoming signal is depleted by thermal noise. There are conditions under which the noise figure for the combination of an optical fiber amplifier and a photo diode is superior to the noise figure for an avalanche photo diode. We optimized the gains of the optical fiber amplifier and the TIA in our LIDAR system such that it would be capable of detecting a single photon. As a result, the detection limit of our system is determined by shot noise. We have previously demonstrated scanning up to a range of 80 m with this LIDAR system with a 2 mm diameter of receiving lens. We improved the optical amplifier and the peak output power of LIDAR was over 10KW. We redesigned the sensor-head and improved coupling efficiency. As a result, we succeeded in scanning over a range of 100 m. This small and highly sensitive measurement technology shows great potential for use in LIDAR.

NDSC and JPL stratospheric lidars

NASA Technical Reports Server (NTRS)

McDermid, I. Stuart

1995-01-01

The Network for the Detection of Stratospheric Change is an international cooperation providing a set of high-quality, remote-sensing instruments at observing stations around the globe. A brief description of the NDSC and its goals is presented. Lidar has been selected as the NDSC instrument for measurements of stratospheric profiles of ozone, temperature, and aerosol. The Jet Propulsion Laboratory has developed and implemented two stratospheric lidar systems for NDSC. These are located at Table Mountain, California, and at Mauna Loa, Hawaii. These systems, which utilize differential absorption lidar, Rayleigh lidar, raman lidar, and backscatter lidar, to measure ozone, temperature, and aerosol profiles in the stratosphere are briefly described. Examples of results obtained for both long-term and individual profiles are presented.

Software design of control system of CCD side-scatter lidar

NASA Astrophysics Data System (ADS)

Kuang, Zhiqiang; Liu, Dong; Deng, Qian; Zhang, Zhanye; Wang, Zhenzhu; Yu, Siqi; Tao, Zongming; Xie, Chenbo; Wang, Yingjian

2018-03-01

Because of the existence of blind zone and transition zone, the application of backscattering lidar in near-ground is limited. The side-scatter lidar equipped with the Charge Coupled Devices (CCD) can separate the transmitting and receiving devices to avoid the impact of the geometric factors which is exited in the backscattering lidar and, detect the more precise near-ground aerosol signals continuously. Theories of CCD side-scatter lidar and the design of control system are introduced. The visible control of laser and CCD and automatic data processing method of the side-scatter lidar are developed by using the software of Visual C #. The results which are compared with the calibration of the atmospheric aerosol lidar data show that signals from the CCD side- scatter lidar are convincible.

Image-Based Airborne LiDAR Point Cloud Encoding for 3d Building Model Retrieval

NASA Astrophysics Data System (ADS)

Chen, Yi-Chen; Lin, Chao-Hung

2016-06-01

With the development of Web 2.0 and cyber city modeling, an increasing number of 3D models have been available on web-based model-sharing platforms with many applications such as navigation, urban planning, and virtual reality. Based on the concept of data reuse, a 3D model retrieval system is proposed to retrieve building models similar to a user-specified query. The basic idea behind this system is to reuse these existing 3D building models instead of reconstruction from point clouds. To efficiently retrieve models, the models in databases are compactly encoded by using a shape descriptor generally. However, most of the geometric descriptors in related works are applied to polygonal models. In this study, the input query of the model retrieval system is a point cloud acquired by Light Detection and Ranging (LiDAR) systems because of the efficient scene scanning and spatial information collection. Using Point clouds with sparse, noisy, and incomplete sampling as input queries is more difficult than that by using 3D models. Because that the building roof is more informative than other parts in the airborne LiDAR point cloud, an image-based approach is proposed to encode both point clouds from input queries and 3D models in databases. The main goal of data encoding is that the models in the database and input point clouds can be consistently encoded. Firstly, top-view depth images of buildings are generated to represent the geometry surface of a building roof. Secondly, geometric features are extracted from depth images based on height, edge and plane of building. Finally, descriptors can be extracted by spatial histograms and used in 3D model retrieval system. For data retrieval, the models are retrieved by matching the encoding coefficients of point clouds and building models. In experiments, a database including about 900,000 3D models collected from the Internet is used for evaluation of data retrieval. The results of the proposed method show a clear superiority over related methods.

Refurbishment of durban fixed ukzn lidar for atmospheric studies - current status

NASA Astrophysics Data System (ADS)

Sivakumar, Venkataraman

2018-04-01

The fixed LIDAR system at University of KwaZulu-Natal (UKZN) in Durban was installed in 1999 and operated until 2004. In 2004, the system was relocated and operation closed due to various technical and instrument problems. The restructuring of the LIDAR system was initiated in 2013 and it is now used to measure vertical aerosol profiles in the height range 03-25 km. Here, we describe the present system in detail, including technical specifications and results obtained from a recent LIDAR calibration campaign.

Application of a Terrestrial LIDAR System for Elevation Mapping in Terra Nova Bay, Antarctica.

PubMed

Cho, Hyoungsig; Hong, Seunghwan; Kim, Sangmin; Park, Hyokeun; Park, Ilsuk; Sohn, Hong-Gyoo

2015-09-16

A terrestrial Light Detection and Ranging (LIDAR) system has high productivity and accuracy for topographic mapping, but the harsh conditions of Antarctica make LIDAR operation difficult. Low temperatures cause malfunctioning of the LIDAR system, and unpredictable strong winds can deteriorate data quality by irregularly shaking co-registration targets. For stable and efficient LIDAR operation in Antarctica, this study proposes and demonstrates the following practical solutions: (1) a lagging cover with a heating pack to maintain the temperature of the terrestrial LIDAR system; (2) co-registration using square planar targets and two-step point-merging methods based on extracted feature points and the Iterative Closest Point (ICP) algorithm; and (3) a georeferencing module consisting of an artificial target and a Global Navigation Satellite System (GNSS) receiver. The solutions were used to produce a topographic map for construction of the Jang Bogo Research Station in Terra Nova Bay, Antarctica. Co-registration and georeferencing precision reached 5 and 45 mm, respectively, and the accuracy of the Digital Elevation Model (DEM) generated from the LIDAR scanning data was ±27.7 cm.

Levels of Autonomy and Autonomous System Performance Assessment for Intelligent Unmanned Systems

DTIC Science & Technology

2014-04-01

LIDAR and camera sensors that is driven entirely by teleoperation would be AL 0. If that same robot used its LIDAR and camera data to generate a...obstacle detection, mapping, path planning 3 CMMAD semi- autonomous counter- mine system (Few 2010) Talon UGV, camera, LIDAR , metal detector...NCAP framework are performed on individual UMS components and do not require mission level evaluations. For example, bench testing of camera, LIDAR

A mobile system combining lidar and sunphotometer on-road measurements: description and first results

NASA Astrophysics Data System (ADS)

Popovici, Ioana; Goloub, Philippe; Podvin, Thierry; Blarel, Luc; Loisil, Rodrigue; Mortier, Augustin; Deroo, Christine; Ducos, Fabrice; Victori, Stéphane; Torres, Benjamin

2018-04-01

The mobile system described in this paper integrates a commercial eye-safe lidar (CIMEL), a sunphotometer and in situ instruments. The system is distinguished by other transportable platforms through its capabilities to perform onroad measurements. The potential of a commercial lidar to provide reliable information on aerosol properties is investigated through comparison with a multi-wavelength Raman lidar. First results from observation campaigns in northern France are presented.

Compact atomic clocks and stabilised laser for space applications

NASA Astrophysics Data System (ADS)

Mileti, Gaetano; Affolderbach, Christoph; Matthey-de-l'Endroit, Renaud

2016-07-01

We present our developments towards next generation compact vapour-cell based atomic frequency standards using a tunable laser diode instead of a traditional discharge lamp. The realisation of two types of Rubidium clocks addressing specific applications is in progress: high performance frequency standards for demanding applications such as satellite navigation, and chip-scale atomic clocks, allowing further miniaturisation of the system. The stabilised laser source constitutes the main technological novelty of these new standards, allowing a more efficient preparation and interrogation of the atoms and hence an improvement of the clock performances. However, before this key component may be employed in a commercial and ultimately in a space-qualified instrument, further studies are necessary to demonstrate their suitability, in particular concerning their reliability and long-term operation. The talk will present our preliminary investigations on this subject. The stabilised laser diode technology developed for our atomic clocks has several other applications on ground and in space. We will conclude our talk by illustrating this for the example of a recently completed ESA project on a 1.6 microns wavelength reference for a future space-borne Lidar. This source is based on a Rubidium vapour cell providing the necessary stability and accuracy, while a second harmonic generator and a compact optical comb generated from an electro-optic modulator allow to transfer these properties from the Rubidium wavelength (780nm) to the desired spectral range.

Adaptive Data Processing Technique for Lidar-Assisted Control to Bridge the Gap between Lidar Systems and Wind Turbines: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schlipf, David; Raach, Steffen; Haizmann, Florian

2015-12-14

This paper presents first steps toward an adaptive lidar data processing technique crucial for lidar-assisted control in wind turbines. The prediction time and the quality of the wind preview from lidar measurements depend on several factors and are not constant. If the data processing is not continually adjusted, the benefit of lidar-assisted control cannot be fully exploited, or can even result in harmful control action. An online analysis of the lidar and turbine data are necessary to continually reassess the prediction time and lidar data quality. In this work, a structured process to develop an analysis tool for the predictionmore » time and a new hardware setup for lidar-assisted control are presented. The tool consists of an online estimation of the rotor effective wind speed from lidar and turbine data and the implementation of an online cross correlation to determine the time shift between both signals. Further, initial results from an ongoing campaign in which this system was employed for providing lidar preview for feed-forward pitch control are presented.« less

Comparison of 2 micron Ho and 10 micron CO2 lidar for atmospheric backscatter and Doppler windshear detection

NASA Technical Reports Server (NTRS)

Killinger, Dennis

1991-01-01

The development of eye-safe, solid-state Lidar systems is discussed, with an emphasis on Coherent Doppler Lidar for Atmospheric Wind Measurements. The following subject areas are covered: tunable Ho DIAL (Differential Absorption Lidar)/lidar atmospheric measurements; atmospheric turbulence measurements and detector arrays; diurnal measurements of C(sub n)(sup 2) for KSC lidar measurements; and development of single-frequency Ho laser/lidar.

Aerosol backscatter lidar calibration and data interpretation

NASA Technical Reports Server (NTRS)

Kavaya, M. J.; Menzies, R. T.

1984-01-01

A treatment of the various factors involved in lidar data acquisition and analysis is presented. This treatment highlights sources of fundamental, systematic, modeling, and calibration errors that may affect the accurate interpretation and calibration of lidar aerosol backscatter data. The discussion primarily pertains to ground based, pulsed CO2 lidars that probe the troposphere and are calibrated using large, hard calibration targets. However, a large part of the analysis is relevant to other types of lidar systems such as lidars operating at other wavelengths; continuous wave (CW) lidars; lidars operating in other regions of the atmosphere; lidars measuring nonaerosol elastic or inelastic backscatter; airborne or Earth-orbiting lidar platforms; and lidars employing combinations of the above characteristics.

Quantifying TOLNet Ozone Lidar Accuracy During the 2014 DISCOVER-AQ and FRAPPE Campaigns

NASA Technical Reports Server (NTRS)

Wang, Lihua; Newchurch, Michael J.; Alvarez, Raul J., II; Berkoff, Timothy A.; Brown, Steven S.; Carrion, William; De Young, Russell J.; Johnson, Bryan J.; Ganoe, Rene; Gronoff, Guillaume;

Quantifying TOLNet ozone lidar accuracy during the 2014 DISCOVER-AQ and FRAPPÉ campaigns

NASA Astrophysics Data System (ADS)

Wang, Lihua; Newchurch, Michael J.; Alvarez, Raul J., II; Berkoff, Timothy A.; Brown, Steven S.; Carrion, William; De Young, Russell J.; Johnson, Bryan J.; Ganoe, Rene; Gronoff, Guillaume; Kirgis, Guillaume; Kuang, Shi; Langford, Andrew O.; Leblanc, Thierry; McDuffie, Erin E.; McGee, Thomas J.; Pliutau, Denis; Senff, Christoph J.; Sullivan, John T.; Sumnicht, Grant; Twigg, Laurence W.; Weinheimer, Andrew J.

2017-10-01

The Tropospheric Ozone Lidar Network (TOLNet) is a unique network of lidar systems that measure high-resolution atmospheric profiles of ozone. The accurate characterization of these lidars is necessary to determine the uniformity of the network calibration. From July to August 2014, three lidars, the TROPospheric OZone (TROPOZ) lidar, the Tunable Optical Profiler for Aerosol and oZone (TOPAZ) lidar, and the Langley Mobile Ozone Lidar (LMOL), of TOLNet participated in the Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) mission and the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ) to measure ozone variations from the boundary layer to the top of the troposphere. This study presents the analysis of the intercomparison between the TROPOZ, TOPAZ, and LMOL lidars, along with comparisons between the lidars and other in situ ozone instruments including ozonesondes and a P-3B airborne chemiluminescence sensor. The TOLNet lidars measured vertical ozone structures with an accuracy generally better than ±15 % within the troposphere. Larger differences occur at some individual altitudes in both the near-field and far-field range of the lidar systems, largely as expected. In terms of column average, the TOLNet lidars measured ozone with an accuracy better than ±5 % for both the intercomparison between the lidars and between the lidars and other instruments. These results indicate that these three TOLNet lidars are suitable for use in air quality, satellite validation, and ozone modeling efforts.

Pulse-compression ghost imaging lidar via coherent detection.

PubMed

Deng, Chenjin; Gong, Wenlin; Han, Shensheng

2016-11-14

Ghost imaging (GI) lidar, as a novel remote sensing technique, has been receiving increasing interest in recent years. By combining pulse-compression technique and coherent detection with GI, we propose a new lidar system called pulse-compression GI lidar. Our analytical results, which are backed up by numerical simulations, demonstrate that pulse-compression GI lidar can obtain the target's spatial intensity distribution, range and moving velocity. Compared with conventional pulsed GI lidar system, pulse-compression GI lidar, without decreasing the range resolution, is easy to obtain high single pulse energy with the use of a long pulse, and the mechanism of coherent detection can eliminate the influence of the stray light, which is helpful to improve the detection sensitivity and detection range.

Mechanical design of a lidar system for space applications - LITE

NASA Technical Reports Server (NTRS)

Crockett, Sharon K.

1990-01-01

The Lidar In-Space Technology Experiment (LITE) is a Shuttle experiment that will demonstrate the first use of a lidar system in space. Its design process must take into account not only the system design but also the unique design requirements for spaceborne experiment.

A Comparison of Foliage Profiles in the Sierra National Forest Obtained with a Full-Waveform Under-Canopy EVI Lidar System with the Foliage Profiles Obtained with an Airborne Full-Waveform LVIS Lidar System

NASA Technical Reports Server (NTRS)

Zhao, Feng; Yang, Xiaoyuan; Strahler, Alan H.; Schaaf, Crystal L.; Yao, Tian; Wang, Zhuosen; Roman, Miguel O.; Woodcock, Curtis E.; Ni-Meister, Wenge; Jupp, David L. B.;

Impact of Lidar Wind Sounding on Mesoscale Forecast

NASA Technical Reports Server (NTRS)

Miller, Timothy L.; Chou, Shih-Hung; Goodman, H. Michael (Technical Monitor)

2001-01-01

An Observing System Simulation Experiment (OSSE) was conducted to study the impact of airborne lidar wind sounding on mesoscale weather forecast. A wind retrieval scheme, which interpolates wind data from a grid data system, simulates the retrieval of wind profile from a satellite lidar system. A mesoscale forecast system based on the PSU/NCAR MM5 model is developed and incorporated the assimilation of the retrieved line-of-sight wind. To avoid the "identical twin" problem, the NCEP reanalysis data is used as our reference "nature" atmosphere. The simulated space-based lidar wind observations were retrieved by interpolating the NCEP values to the observation locations. A modified dataset obtained by smoothing the NCEP dataset was used as the initial state whose forecast was sought to be improved by assimilating the retrieved lidar observations. Forecasts using wind profiles with various lidar instrument parameters has been conducted. The results show that to significantly improve the mesoscale forecast the satellite should fly near the storm center with large scanning radius. Increasing lidar firing rate also improves the forecast. Cloud cover and lack of aerosol degrade the quality of the lidar wind data and, subsequently, the forecast.

LABVIEW graphical user interface for precision multichannel alignment of Raman lidar at Jet Propulsion Laboratory, Table Mountain Facility.

PubMed

Aspey, R A; McDermid, I S; Leblanc, T; Howe, J W; Walsh, T D

2008-09-01

The Jet Propulsion Laboratory operates lidar systems at Table Mountain Facility (TMF), California (34.4 degrees N, 117.7 degrees W) and Mauna Loa Observatory, Hawaii (19.5 degrees N, 155.6 degrees W) under the framework of the Network for the Detection of Atmospheric Composition Change. To complement these systems a new Raman lidar has been developed at TMF with particular attention given to optimizing water vapor profile measurements up to the tropopause and lower stratosphere. The lidar has been designed for accuracies of 5% up to 12 km in the free troposphere and a detection capability of <5 ppmv. One important feature of the lidar is a precision alignment system using range resolved data from eight Licel transient recorders, allowing fully configurable alignment via a LABVIEW/C++ graphical user interface (GUI). This allows the lidar to be aligned on any channel while simultaneously displaying signals from other channels at configurable altitude/bin combinations. The general lidar instrumental setup and the details of the alignment control system, data acquisition, and GUI alignment software are described. Preliminary validation results using radiosonde and lidar intercomparisons are briefly presented.

Remote wind sensing with a CW diode laser lidar beyond the coherence regime.

PubMed

Hu, Qi; Rodrigo, Peter John; Pedersen, Christian

2014-08-15

We experimentally demonstrate for the first time (to our knowledge) a coherent CW lidar system capable of wind speed measurement at a probing distance beyond the coherence regime of the light source. A side-by-side wind measurement was conducted on the field using two lidar systems with identical optical designs but different laser linewidths. While one system was operating within the coherence regime, the other was measuring at least 2.4 times the coherence range. The probing distance of both lidars is 85 m and the radial wind speed correlation was measured to be r2=0.965 between the two lidars at a sampling rate of 2 Hz. Based on our experimental results, we describe a practical guideline for designing a wind lidar operating beyond the coherence regime.

Wind field measurement in the nonprecipitous regions surrounding storms by an airborne pulsed Doppler lidar system, appendix A

NASA Technical Reports Server (NTRS)

Bilbro, J. W.; Vaughan, W. W.

1980-01-01

Coherent Doppler lidar appears to hold great promise in contributing to the basic store of knowledge concerning flow field characteristics in the nonprecipitous regions surrounding severe storms. The Doppler lidar, through its ability to measure clear air returns, augments the conventional Doppler radar system, which is most useful in the precipitous regions of the storm. A brief description of the Doppler lidar severe storm measurement system is provided along with the technique to be used in performing the flow field measurements. The application of the lidar is addressed, and the planned measurement program is outlined.

Improvement of highly sensitive lidar with a thumb-sized sensor-head built using an optical fiber preamplifier

NASA Astrophysics Data System (ADS)

Inoue, Daisuke; Ichikawa, Tadashi; Matsubara, Hiroyuki; Mao, Xueon; Maeda, Mitsutoshi; Nagashima, Chie; Kagami, Manabu

2012-06-01

We have developed a LIDAR system with a sensor head which, although it includes a scanning mechanism, is less than 20 cc in size. The system is not only small, but is also highly sensitive. Our LIDAR system is based on time-of-flight measurements, and incorporates an optical fiber. The main feature of our system is the utilization of optical amplifiers for both the transmitter and the receiver, and the optical amplifiers enable us to exceed the detection limit set by thermal noise. In conventional LIDAR systems the detection limit is determined by the thermal noise, because the avalanche photo-diodes (APD) and trans-impedance amplifiers (TIA) that they use detect the received signals directly. In the case of our LIDAR system, the received signal is amplified by an optical fiber amplifier before reaching the photo diode and the TIA. Therefore, our LIDAR system boosts the signal level before the weak incoming signal is depleted by thermal noise. There are conditions under which the noise figure for the combination of an optical fiber amplifier and a photo diode is superior to the noise figure for an avalanche photo diode. We optimized the gains of the optical fiber amplifier and the TIA in our LIDAR system such that it would be capable of detecting a single photon. As a result, the detection limit of our system is determined by shot noise. We have previously demonstrated optical pre-amplified LIDAR with a perfect co-axial optical system[1]. For this we used a variable optical attenuator to remove internal reflection from the transmission and receiving lenses. However, the optical attenuator had an insertion loss of 6dB which reduced the sensitivity of the LIDAR. We re-designed the optical system such that it was semi-co-axial and removed the variable optical attenuator. As a result, we succeeded in scanning up to a range of 80 m. This small and highly sensitive measurement technology shows great potential for use in LIDAR.

Analysis of measurements for solid state laser remote lidar system

NASA Technical Reports Server (NTRS)

Amzajerdian, Farzin

1995-01-01

The merits of using lidar systems for remote measurements of various atmospheric processes such as wind, turbulence, moisture, and aerosol concentration are widely recognized. Although the lidar technology has progressed considerably over the past two decades, significant research particularly in the area of solid state lidars remains to be conducted in order to fully exploit this technology. The work performed by the UAH (University of Alabama in Huntsville) personnel under this Delivery Order concentrated on analyses of measurements required in support of solid state laser remote sensing lidar systems which are to be designed, deployed, and used to measure atmospheric processes and constituents. UAH personnel has studied and recommended to NASA/MSFC the requirements of the optical systems needed to characterize the detection devices suitable for solid state wavelengths and to evaluate various heterodyne detection schemes. The 2-micron solid state laser technology was investigated and several preliminary laser designs were developed and their performance for remote sensing of atmospheric winds and clouds from a spaceborne platform were specified. In addition to the laser source and the detector, the other critical technologies necessary for global wind measurements by a spaceborne solid state coherent lidar systems were identified to be developed and demonstrated. As part of this work, an analysis was performed to determine the atmospheric wind velocity estimation accuracy using the line-of-sight measurements of a scanning coherent lidar. Under this delivery order, a computer database of materials related to the theory, development, testing, and operation of lidar systems was developed to serve as a source of information for lidar research and development.

Solid-State, High Energy 2-Micron Laser Development for Space-Based Remote Sensing

NASA Technical Reports Server (NTRS)

Singh, Upendra N.

2010-01-01

Lidar (light detection and ranging) remote sensing enjoys the advantages of excellent vertical and horizontal resolution; pointing capability; a signal source independent from natural light; and control and knowledge of transmitted wavelength, pulse shape, and polarization and received polarization. Lidar in space is an emerging technology now being developing to fit applications where passive sensors cannot meet current measurement requirements. Technical requirements for space lidar are more demanding than for ground-based or airborne systems. Perhaps the most distinguishing characteristics of space lidars are the environmental requirements. Space lidar systems must be specially designed to survive the mechanical vibration loads of launch and operate in the vacuum of space where exposure to ionizing radiation limits the electronic components available. Finally, space lidars must be designed to be highly reliable because they must operate without the need for repair or adjustment. Lifetime requirements tend to be important drivers of the overall system design. The maturity of the required technologies is a key to the development of any space lidar system. NASA entered a new era in the 1990 s with the approval of several space-based remote sensing missions employing laser radar (lidar) techniques. Following the steps of passive remote sensing and then active radar remote sensing, lidar sensors were a logical next step, providing independence from natural light sources, and better spatial resolution and smaller sensor size than radar sensors. The shorter electromagnetic wavelengths of laser light also allowed signal reflectance from air molecules and aerosol particles. The smaller receiver apertures allowed the concept of scanning the sensor field of view. However, technical problems with several space-based lidar missions during that decade led to concern at NASA about the risk of lidar missions. An external panel was convened to make recommendations to NASA. Their report in 2000 strongly advocated that NASA maintain in-house laser and lidar capability, and that NASA should work to lower the technology risk for all future lidar missions. A multi-Center NASA team formulated an integrated NASA strategy to provide the technology and maturity of systems necessary to make Lidar/Laser systems viable for space-based study and monitoring of the Earth's atmosphere. In 2002 the NASA Earth Science Enterprise (ESE) and Office of Aerospace Technology (OAT) created the Laser Risk Reduction Program (LRRP) and directed NASA Langley Research Center (LaRC) and Goddard Space Flight Center to carry out synergistic and complementary research towards solid-state lasers/lidars developments for space-based remote sensing applications.

Linear LIDAR versus Geiger-mode LIDAR: impact on data properties and data quality

NASA Astrophysics Data System (ADS)

Ullrich, A.; Pfennigbauer, M.

2016-05-01

LIDAR has become the inevitable technology to provide accurate 3D data fast and reliably even in adverse measurement situations and harsh environments. It provides highly accurate point clouds with a significant number of additional valuable attributes per point. LIDAR systems based on Geiger-mode avalanche photo diode arrays, also called single photon avalanche photo diode arrays, earlier employed for military applications, now seek to enter the commercial market of 3D data acquisition, advertising higher point acquisition speeds from longer ranges compared to conventional techniques. Publications pointing out the advantages of these new systems refer to the other category of LIDAR as "linear LIDAR", as the prime receiver element for detecting the laser echo pulses - avalanche photo diodes - are used in a linear mode of operation. We analyze the differences between the two LIDAR technologies and the fundamental differences in the data they provide. The limitations imposed by physics on both approaches to LIDAR are also addressed and advantages of linear LIDAR over the photon counting approach are discussed.

A cloud masking algorithm for EARLINET lidar systems

NASA Astrophysics Data System (ADS)

Binietoglou, Ioannis; Baars, Holger; D'Amico, Giuseppe; Nicolae, Doina

2015-04-01

Cloud masking is an important first step in any aerosol lidar processing chain as most data processing algorithms can only be applied on cloud free observations. Up to now, the selection of a cloud-free time interval for data processing is typically performed manually, and this is one of the outstanding problems for automatic processing of lidar data in networks such as EARLINET. In this contribution we present initial developments of a cloud masking algorithm that permits the selection of the appropriate time intervals for lidar data processing based on uncalibrated lidar signals. The algorithm is based on a signal normalization procedure using the range of observed values of lidar returns, designed to work with different lidar systems with minimal user input. This normalization procedure can be applied to measurement periods of only few hours, even if no suitable cloud-free interval exists, and thus can be used even when only a short period of lidar measurements is available. Clouds are detected based on a combination of criteria including the magnitude of the normalized lidar signal and time-space edge detection performed using the Sobel operator. In this way the algorithm avoids misclassification of strong aerosol layers as clouds. Cloud detection is performed using the highest available time and vertical resolution of the lidar signals, allowing the effective detection of low-level clouds (e.g. cumulus humilis). Special attention is given to suppress false cloud detection due to signal noise that can affect the algorithm's performance, especially during day-time. In this contribution we present the details of algorithm, the effect of lidar characteristics (space-time resolution, available wavelengths, signal-to-noise ratio) to detection performance, and highlight the current strengths and limitations of the algorithm using lidar scenes from different lidar systems in different locations across Europe.

Lidar systems for measuring visibility : a technical assessment

DOT National Transportation Integrated Search

1974-09-01

A study has been made of the feasibility of using a laser backscatter system (lidar) to measure slant visibility at airports. This report summarizes the present status of lidar from a technical standpoint. Based largely on the results of experimental...

Multifunction LIDAR sensors for noncontact, speed, and complex rail dynamics.

DOT National Transportation Integrated Search

2014-07-01

The results of an extensive series of tests are presented to evaluate the viability and applicability of LIDAR systems for measuring : track speed, distance, and curvature in revenue service. The tests indicate that a LIDAR system can successfully pr...

Efficient, space-based, PM 100W thulium fiber laser for pumping Q-switched 2μm Ho:YLF for global winds and carbon dioxide lidar

NASA Astrophysics Data System (ADS)

Engin, Doruk; Mathason, Brian; Storm, Mark

2017-08-01

Global wind measurements are critically needed to improve and extend NOAA weather forecasting that impacts U.S. economic activity such as agriculture crop production, as well as hurricane forecasting, flooding, and FEMA disaster planning.1 NASA and the 2007 National Research Council (NRC) Earth Science Decadal Study have also identified global wind measurements as critical for global change research. NASA has conducted aircraft-based wind lidar measurements using 2 um Ho:YLF lasers, which has shown that robust wind measurements can be made. Fibertek designed and demonstrated a high-efficiency, 100 W average power continuous wave (CW) 1940 nm thulium (Tm)- doped fiber laser bread-board system meeting all requirements for a NASA Earth Science spaceflight 2 μm Ho:YLF pump laser. Our preliminary design shows that it is possible to package the laser for high-reliability spaceflight operation in an ultra-compact 2″x8″x14″ size and weight <8.5 lbs. A spaceflight 100 W polarization maintaining (PM) Tm laser provides a path to space for a pulsed, Q-switched 2 μm Ho:YLF laser with 30-80 mJ/pulse range at 100-200 Hz repletion rates.

Fast widely-tunable single-frequency 2-micron laser for remote-sensing applications

NASA Astrophysics Data System (ADS)

Henderson, Sammy W.; Hale, Charley P.

2017-08-01

We are developing a family of fast, widely-tunable cw diode-pumped single frequency solid-state lasers, called Swift. The Swift laser architecture is compatible with operation using many different solid-state laser crystals for operation at various emission lines between 1 and 2.1 micron. The initial prototype Swift laser using a Tm,Ho:YLF laser crystal near 2.05 micron wavelength achieved over 100 mW of single frequency cw output power, up to 50 GHz-wide, fast, mode-hop-free piezoelectric tunability, and 100 kHz/ms frequency stability. For the Tm,Ho:YLF laser material, the fast 50 GHz tuning range can be centered at any wavelength from 2047-2059 nm using appropriate intracavity spectral filters. The frequency stability and power are sufficient to serve as the local oscillator (LO) laser in long-range coherent wind-measuring lidar systems, as well as a frequency-agile master oscillator (MO) or injection-seed source for larger pulsed transmitter lasers. The rapid and wide frequency tunablity meets the requirements for integrated-path or range-resolved differential absorption lidar or applications where targets with significantly different line of sight velocities (Doppler shifts) must be tracked. Initial demonstration of an even more compact version of the Swift is also described which requires less prime power and produces less waste heat.

Modeling of a field-widened Michelson interferometric filter for application in a high spectral resolution lidar

NASA Astrophysics Data System (ADS)

Liu, Dong; Hostetler, Chris; Cook, Anthony; Miller, Ian; Hair, Johnathan

2011-11-01

High spectral resolution lidars (HSRLs) are increasingly being deployed on aircraft and called for on future space-based missions. The HSRL technique relies on spectral discrimination of the atmospheric backscatter signals to enable independent, unambiguous retrieval of aerosol extinction and backscatter. A compact, monolithic field-widened Michelson interferometer is being developed as the spectral discrimination filter for an HSRL system at NASA Langley Research Center. The interferometer consists of a cubic beam splitter, a solid glass arm, and an air arm. The spacer that connects the air arm mirror to the main part of the interferometer is designed to optimize thermal compensation such that the maximum interference can be tuned with great precision to the transmitted laser wavelength. In this paper, a comprehensive radiometric model for the field-widened Michelson interferometeric spectral filter is presented. The model incorporates the angular distribution and finite cross sectional area of the light source, reflectance of all surfaces, loss of absorption, and lack of parallelism between the air-arm and solid arm, etc. The model can be used to assess the performance of the interferometer and thus it is a useful tool to evaluate performance budgets and to set optical specifications for new designs of the same basic interferometer type.

Lidars as an operational tool for meteorology and advanced atmospheric research

NASA Astrophysics Data System (ADS)

Simeonov, Valentin; Dinoev, Todor; Serikov, Ilya; Froidevaux, Martin; Bartlome, Marcel; Calpini, Bertrand; Bobrovnikov, Sergei; Ristori, Pablo; van den Bergh, Hubert; Parlange, Marc; Archinov, Yury

2010-05-01

The talk will present the concept and observation results of three advanced lidar systems developed recently at the Swiss federal Institute of Technology- Lausanne (EPFL) Switzerland. Two of the systems are Raman lidars for simultaneous water vapor, temperature and aerosol observations and the third one is an ozone UV DIAL system. The Ranan lidars use vibrational water vapor and nitrogen signals to derive water vapor mixing ratio and temperature, aerosol extinction and backscatter are measured using pure-rotational Raman and elastic signals. The first Raman lidar (RALMO) is a fully automated, water vapor /temperature/aerosol lidar developed for operational use by the Swiss meteorological office (MeteoSiss). The lidar supplies water vapor mixing ratio and temperature plus aerosol extinction and backscatter coefficients at 355 nm. The operational range of the lidar is 100-7000 m (night time) and 100- 5000 m (daytime) with time resolution of 30 min. The spatial resolution varies with height from 25 to 300 m in order to maintain the maximum measurement error of 10%. The system is designed to provide long-term database with minimal instrument-induced variations in time of the measured parameters. The lidar has been in regular operation in the main aerological station of Meteoswiss- Payerne since September 2008. The second Raman lidar is a new generation, solar-blind system with an operational range 10-500 m and high spatial (1.5 m) and temporal (1 s) resolutions designed for simultaneous humidity, temperature, and aerosol measurements in the lower atmosphere. To maintain the measurement accuracy while operating with fixed spatial and temporal resolution, the receiver is designed to provide lower than ten dynamic range of the signals within the distance range of the lidar. The lidar has 360° azimuth and 240°elevation scanning ability. The lidar was used in two field campaigns aiming to study the structure of the lower atmosphere over complex terrains and, in particular, to advance our understanding of turbulent blending mechanisms in the unstable atmosphere. The third lidar is an ozone UV DIAL system designed for studies of the upper troposphere, lower stratosphere ozone exchange processes. The lidar is based on a commercial fourth harmonic Nd:YAG laser. The DIAL wavelengths (284 and 304 nm) are produced by stimulated Raman conversion in high pressure nitrogen. A 76 cm in diameter Cassegrein telescope is used in the receiver and the spectral separation of the signals is carried out by an imaging-grating based polychromator. The operational distance of the lidar is 6000 -12000 m ASL with a statistical error lower than 10%. The lidar is deployed at the High Altitude Research Station Jungfraujoch at 3600 m altitude in the Swiss Alps. The lidar accuracy was verified by comparison to profiles taken by ECC balloon-borne sondes launched by Meteoswiss from Payerne. The lidar has been in use from September 2008 and since that time several stratospheric intrusions and cases of intercontinental transport and transport from the atmospheric boundary layer have been observed.

Airborne Coherent Lidar for Advanced In-Flight Measurements (ACLAIM) Flight Testing of the Lidar Sensor

NASA Technical Reports Server (NTRS)

Soreide, David C.; Bogue, Rodney K.; Ehernberger, L. J.; Hannon, Stephen M.; Bowdle, David A.

2000-01-01

The purpose of the ACLAIM program is ultimately to establish the viability of light detection and ranging (lidar) as a forward-looking sensor for turbulence. The goals of this flight test are to: 1) demonstrate that the ACLAIM lidar system operates reliably in a flight test environment, 2) measure the performance of the lidar as a function of the aerosol backscatter coefficient (beta), 3) use the lidar system to measure atmospheric turbulence and compare these measurements to onboard gust measurements, and 4) make measurements of the aerosol backscatter coefficient, its probability distribution and spatial distribution. The scope of this paper is to briefly describe the ACLAIM system and present examples of ACLAIM operation in flight, including comparisons with independent measurements of wind gusts, gust-induced normal acceleration, and the derived eddy dissipation rate.

Performance Modeling of an Airborne Raman Water Vapor Lidar

NASA Technical Reports Server (NTRS)

Whiteman, D. N.; Schwemmer, G.; Berkoff, T.; Plotkin, H.; Ramos-Izquierdo, L.; Pappalardo, G.

2000-01-01

A sophisticated Raman lidar numerical model had been developed. The model has been used to simulate the performance of two ground-based Raman water vapor lidar systems. After tuning the model using these ground-based measurements, the model is used to simulate the water vapor measurement capability of an airborne Raman lidar under both day-and night-time conditions for a wide range of water vapor conditions. The results indicate that, under many circumstances, the daytime measurements possess comparable resolution to an existing airborne differential absorption water vapor lidar while the nighttime measurement have higher resolution. In addition, a Raman lidar is capable of measurements not possible using a differential absorption system.

High resolution Doppler lidar

NASA Technical Reports Server (NTRS)

Abreu, Vincent J.; Hays, Paul B.; Barnes, John E.

1989-01-01

A high resolution lidar system was implemented to measure winds in the lower atmosphere. The wind speed along the line of sight was determined by measuring the Doppler shift of the aerosol backscattered laser signal. The system in its present configuration is stable, and behaves as indicated by theoretical simulations. This system was built to demonstrate the capabilities of the detector system as a prototype for a spaceborne lidar. The detector system investigated consisted of a plane Fabry-Perot etalon, and a 12-ring anode detector. This system is generically similar to the Fabry-Perot interferometer developed for passive wind measurements on board the Dynamics Explorer satellite. That this detector system performs well in a lidar configuration was demonstrated.

Improving the detection of wind fields from LIDAR aerosol backscatter using feature extraction

NASA Astrophysics Data System (ADS)

Bickel, Brady R.; Rotthoff, Eric R.; Walters, Gage S.; Kane, Timothy J.; Mayor, Shane D.

2016-04-01

The tracking of winds and atmospheric features has many applications, from predicting and analyzing weather patterns in the upper and lower atmosphere to monitoring air movement from pig and chicken farms. Doppler LIDAR systems exist to quantify the underlying wind speeds, but cost of these systems can sometimes be relatively high, and processing limitations exist. The alternative is using an incoherent LIDAR system to analyze aerosol backscatter. Improving the detection and analysis of wind information from aerosol backscatter LIDAR systems will allow for the adoption of these relatively low cost instruments in environments where the size, complexity, and cost of other options are prohibitive. Using data from a simple aerosol backscatter LIDAR system, we attempt to extend the processing capabilities by calculating wind vectors through image correlation techniques to improve the detection of wind features.

Research on the space-borne coherent wind lidar technique and the prototype experiment

NASA Astrophysics Data System (ADS)

Gao, Long; Tao, Yuliang; An, Chao; Yang, Jukui; Du, Guojun; Zheng, Yongchao

2016-10-01

Space-borne coherent wind lidar technique is considered as one of the most promising and appropriate remote Sensing methods for successfully measuring the whole global vector wind profile between the lower atmosphere and the middle atmosphere. Compared with other traditional methods, the space-borne coherent wind lidar has some advantages, such as, the all-day operation; many lidar systems can be integrated into the same satellite because of the light-weight and the small size, eye-safe wavelength, and being insensitive to the background light. Therefore, this coherent lidar could be widely applied into the earth climate research, disaster monitoring, numerical weather forecast, environment protection. In this paper, the 2μm space-borne coherent wind lidar system for measuring the vector wind profile is proposed. And the technical parameters about the sub-system of the coherent wind lidar are simulated and the all sub-system schemes are proposed. For sake of validating the technical parameters of the space-borne coherent wind lidar system and the optical off-axis telescope, the weak laser signal detection technique, etc. The proto-type coherent wind lidar is produced and the experiments for checking the performance of this proto-type coherent wind lidar are finished with the hard-target and the soft target, and the horizontal wind and the vertical wind profile are measured and calibrated, respectively. For this proto-type coherent wind lidar, the wavelength is 1.54μm, the pulse energy 80μJ, the pulse width 300ns, the diameter of the off-axis telescope 120mm, the single wedge for cone scanning with the 40°angle, and the two dualbalanced InGaAs detector modules are used. The experiment results are well consisted with the simulation process, and these results show that the wind profile between the vertical altitude 4km can be measured, the accuracy of the wind velocity and the wind direction are better than 1m/s and +/-10°, respectively.

Quantifying Vegetation Structure with Lightweight, Rapid-Scanning Terrestrial Lidar

NASA Astrophysics Data System (ADS)

Paynter, I.; Genest, D.; Saenz, E. J.; Strahler, A. H.; Li, Z.; Peri, F.; Schaaf, C.

2016-12-01

Light Detection and Ranging (lidar) is proving a competent technology for observing vegetation structure. Terrestrial laser scanners (TLS) are ground-based instruments which utilize hundreds of thousands to millions of lidar observations to provide detailed structural and reflective information of their surroundings. TLS has enjoyed initial success as a validation tool for satellite and airborne estimates of vegetation structure, and are producing independent estimates with increasing accuracy. Reconstruction techniques for TLS observations of vegetation have also improved rapidly, especially for trees. However, uncertainties and challenges still remain in TLS modelling of vegetation structure, especially in geometrically complex ecosystems such as tropical forests (where observation extent and density is hampered by occlusion) and highly temporally dynamic coastal ecosystems (such as saltmarshes and mangroves), where observations may be restricted to narrow microstates. Some of these uncertainties can be mitigated, and challenges met, through the use of lidar instruments optimized for favorable deployment logistics through low weight, rapid scanning, and improved durability. We have conducted studies of vegetation structure in temperate and tropical forests, saltmarshes and mangroves, utilizing a highly portable TLS with considerable deployment flexibility, the Compact Biomass Lidar (CBL). We show results from studies in the temperate Long Term Ecological Research site of Harvard Forest (MA, USA); the tropical forested long-term Carbono sites of La Selva Biological Station (Sarapiqui, Costa Rica); and the saltmarsh LTER of Plum Island (MA, USA). These results demonstrate the improvements to observations in these ecosystems which are facilitated by the specifications of the CBL (and similar TLS) which are optimized for favorable deployment logistics and flexibility. We show the benefits of increased numbers of scanning positions, and specialized deployment platforms to meet ecosystem challenges.

Accuracy assessment of a mobile terrestrial lidar survey at Padre Island National Seashore

USGS Publications Warehouse

Lim, Samsung; Thatcher, Cindy A.; Brock, John C.; Kimbrow, Dustin R.; Danielson, Jeffrey J.; Reynolds, B.J.

2013-01-01

The higher point density and mobility of terrestrial laser scanning (light detection and ranging (lidar)) is desired when extremely detailed elevation data are needed for mapping vertically orientated complex features such as levees, dunes, and cliffs, or when highly accurate data are needed for monitoring geomorphic changes. Mobile terrestrial lidar scanners have the capability for rapid data collection on a larger spatial scale compared with tripod-based terrestrial lidar, but few studies have examined the accuracy of this relatively new mapping technology. For this reason, we conducted a field test at Padre Island National Seashore of a mobile lidar scanner mounted on a sport utility vehicle and integrated with a position and orientation system. The purpose of the study was to assess the vertical and horizontal accuracy of data collected by the mobile terrestrial lidar system, which is georeferenced to the Universal Transverse Mercator coordinate system and the North American Vertical Datum of 1988. To accomplish the study objectives, independent elevation data were collected by conducting a high-accuracy global positioning system survey to establish the coordinates and elevations of 12 targets spaced throughout the 12 km transect. These independent ground control data were compared to the lidar scanner-derived elevations to quantify the accuracy of the mobile lidar system. The performance of the mobile lidar system was also tested at various vehicle speeds and scan density settings (e.g. field of view and linear point spacing) to estimate the optimal parameters for desired point density. After adjustment of the lever arm parameters, the final point cloud accuracy was 0.060 m (east), 0.095 m (north), and 0.053 m (height). The very high density of the resulting point cloud was sufficient to map fine-scale topographic features, such as the complex shape of the sand dunes.

A Compact Ti:Sapphire Laser With its Third Harmonic Generation (THG) for an Airborne Ozone Differential Absorption Lidar (DIAL) Transmitter

NASA Technical Reports Server (NTRS)

Chen, Songsheng; Storm, Mark E.; Marsh, Waverly D.; Petway, Larry B.; Edwards, William C.; Barnes, James C.

2000-01-01

A compact and high-pulse-energy Ti:Sapphire laser with its Third Harmonic Generation (THG) has been developed for an airborne ozone differential absorption lidar (DIAL) to study the distributions and concentrations of the ozone throughout the troposphere. The Ti:Sapphire laser, pumped by a frequency-doubled Nd:YAG laser and seeded by a single mode diode laser, is operated either at 867 nm or at 900 nm with a pulse repetition frequency of 20 Hz. High energy laser pulses (more than 110 mJ/pulse) at 867 nm or 900 nm with a desired beam quality have been achieved and utilized to generate its third harmonic at 289nm or 300nm, which are on-line and off-line wavelengths of an airborne ozone DIAL. After being experimentally compared with Beta-Barium Borate (beta - BaB2O4 or BBO) nonlinear crystals, two Lithium Triborate (LBO) crystals (5 x 5 x 20 cu mm) are selected for the Third Harmonic Generation (THG). In this paper, we report the Ti:Sapphire laser at 900 nm and its third harmonic at 300 nm. The desired high ultraviolet (UV) output pulse energy is more than 30 mJ at 300 nm and the energy conversion efficiency from 900 nm to 300 nm is 30%.

Issues to be addressed in the design and fabrication of ultralightweight meter-class optics

NASA Astrophysics Data System (ADS)

Krumweide, Gary C.

1998-08-01

There is a growing need for large aperture, ultralightweight, deployable optics for various science, military and commercial compact satellites. This paper will examine the engineering and manufacturing considerations that must be addressed in order to satisfy the requirements for these sought after optics. In order to limit the scope of this paper, only Graphite Fiber Reinforced/Polymer Matrix Composites (GFR/PMC) will be under consideration because of the potential to satisfy ultralightweight mirror requirements. The requirements associated with specular mirror concepts that Composite Optics, Incorporated (COI) has proposed to Air Force Research Laboratory and NASA Langley Research Center for visible range optics and LIDAR optics, respectively, will also be our interest. Moreover, it is the intent of this paper to illustrate how COI's proposed design/manufacturing concepts for visible and LIDAR optics have evolved based on overcoming, or working around, material constraints and/or undesirable characteristics associated with GFR/PMC.

Underwater lidar system: design challenges and application in pollution detection

NASA Astrophysics Data System (ADS)

Gupta, Pradip; Sankolli, Swati; Chakraborty, A.

2016-05-01

The present remote sensing techniques have imposed limitations in the applications of LIDAR Technology. The fundamental sampling inadequacy of the remote sensing data obtained from satellites is that they cannot resolve in the third spatial dimension, the vertical. This limits our possibilities of measuring any vertical variability in the water column. Also the interaction between the physical and biological process in the oceans and their effects at subsequent depths cannot be modeled with present techniques. The idea behind this paper is to introduce underwater LIDAR measurement system by using a LIDAR mounted on an Autonomous Underwater Vehicle (AUV). The paper introduces working principles and design parameters for the LIDAR mounted AUV (AUV-LIDAR). Among several applications the papers discusses the possible use and advantages of AUV-LIDAR in water pollution detection through profiling of Dissolved Organic Matter (DOM) in water bodies.

Aerosol speckle effects on atmospheric pulsed lidar backscattered signals

NASA Technical Reports Server (NTRS)

Murty, S. R.

1989-01-01

Lidar systems using atmospheric aerosols as targets exhibit return signal amplitude and power fluctuations which indicate speckle effects. The effects of refractive turbulence along the path on the aerosol speckle field propagation and on the decorrelation time are studied for coherent pulsed lidar systems.

LiDAR and Image Point Cloud Comparison

DTIC Science & Technology

2014-09-01

UAV unmanned aerial vehicle USGS United States Geological Survey UTM Universal Transverse Mercator WGS 84 World Geodetic System 1984 WSI...19  1.  Physics of LiDAR Systems ................................................................20  III.  DATA AND SOFTWARE...ground control point GPS Global Positioning System IMU inertial measurements unit LiDAR light detection and ranging MI mutual information MVS

Energy Measurement Studies for CO2 Measurement with a Coherent Doppler Lidar System

NASA Technical Reports Server (NTRS)

Beyon, Jeffrey Y.; Koch, Grady J.; Vanvalkenburg, Randal L.; Yu, Jirong; Singh, Upendra N.; Kavaya, Michael J.

2010-01-01

The accurate measurement of energy in the application of lidar system for CO2 measurement is critical. Different techniques of energy estimation in the online and offline pulses are investigated for post processing of lidar returns. The cornerstone of the techniques is the accurate estimation of the spectrum of lidar signal and background noise. Since the background noise is not the ideal white Gaussian noise, simple average level estimation of noise level is not well fit in the energy estimation of lidar signal and noise. A brief review of the methods is presented in this paper.

Progress on development of an airborne two-micron IPDA lidar for water vapor and carbon dioxide column measurements

NASA Astrophysics Data System (ADS)

Singh, Upendra N.; Petros, Mulugeta; Refaat, Tamer F.; Yu, Jirong; Antill, Charles W.; Taylor, Bryant D.; Bowen, Stephen C.; Welters, Angela M.; Remus, Ruben G.; Wong, Teh-Hwa; Reithmaier, Karl; Lee, Jane; Ismail, Syed

2017-09-01

An airborne 2-μm triple-pulse integrated path differential absorption (IPDA) lidar is currently under development at NASA Langley Research Center (LaRC). This lidar targets both atmospheric carbon dioxide (CO2) and water vapor (H2O) column measurements, simultaneously. Advancements in the development of this IPDA lidar are presented in this paper. Updates on advanced two-micron triple-pulse high-energy laser transmitter will be given including packaging and lidar integration status. In addition, receiver development updates will also be presented. This includes a state-of-the-art detection system integrated at NASA Goddard Space Flight Center. This detection system is based on a newly developed HgCdTe (MCT) electron-initiated avalanche photodiode (e-APD) array. Future plan for IPDA lidar system for ground integration, testing and flight validation will be discussed.

Progress on Development of an Airborne Two-Micron IPDA Lidar for Water Vapor and Carbon Dioxide Column Measurements

NASA Technical Reports Server (NTRS)

Singh, Upendra N.; Petros, Mulugeta; Refaat, Tamer F.; Yu, Jirong; Antill, Charles W.; Taylor, Bryant D.; Bowen, Stephen C.; Welters, Angela M.; Remus, Ruben G.; Wong, Teh-Hwa;

UAV Inspection of Electrical Transmission Infrastructure with Path Conformance Autonomy and Lidar-Based Geofences NASA Report on UTM Reference Mission Flights at Southern Company Flights November 2016

NASA Technical Reports Server (NTRS)

Moore, Andrew J.; Schubert, Matthew; Rymer, Nicholas; Balachandran, Swee; Consiglio, Maria; Munoz, Cesar; Smith, Joshua; Lewis, Dexter; Schneider, Paul

2017-01-01

Flights at low altitudes in close proximity to electrical transmission infrastructure present serious navigational challenges: GPS and radio communication quality is variable and yet tight position control is needed to measure defects while avoiding collisions with ground structures. To advance unmanned aerial vehicle (UAV) navigation technology while accomplishing a task with economic and societal benefit, a high voltage electrical infrastructure inspection reference mission was designed. An integrated air-ground platform was developed for this mission and tested in two days of experimental flights to determine whether navigational augmentation was needed to successfully conduct a controlled inspection experiment. The airborne component of the platform was a multirotor UAV built from commercial off-the-shelf hardware and software, and the ground component was a commercial laptop running open source software. A compact ultraviolet sensor mounted on the UAV can locate 'hot spots' (potential failure points in the electric grid), so long as the UAV flight path adequately samples the airspace near the power grid structures. To improve navigation, the platform was supplemented with two navigation technologies: lidar-to-polyhedron preflight processing for obstacle demarcation and inspection distance planning, and trajectory management software to enforce inspection standoff distance. Both navigation technologies were essential to obtaining useful results from the hot spot sensor in this obstacle-rich, low-altitude airspace. Because the electrical grid extends into crowded airspaces, the UAV position was tracked with NASA unmanned aerial system traffic management (UTM) technology. The following results were obtained: (1) Inspection of high-voltage electrical transmission infrastructure to locate 'hot spots' of ultraviolet emission requires navigation methods that are not broadly available and are not needed at higher altitude flights above ground structures. (2) The sensing capability of a novel airborne UV detector was verified with a standard ground-based instrument. Flights with this sensor showed that UAV measurement operations and recording methods are viable. With improved sensor range, UAVs equipped with compact UV sensors could serve as the detection elements in a self-diagnosing power grid. (3) Simplification of rich lidar maps to polyhedral obstacle maps reduces data volume by orders of magnitude, so that computation with the resultant maps in real time is possible. This enables real-time obstacle avoidance autonomy. Stable navigation may be feasible in the GPS-deprived environment near transmission lines by a UAV that senses ground structures and compares them to these simplified maps. (4) A new, formally verified path conformance software system that runs onboard a UAV was demonstrated in flight for the first time. It successfully maneuvered the aircraft after a sudden lateral perturbation that models a gust of wind, and processed lidar-derived polyhedral obstacle maps in real time. (5) Tracking of the UAV in the national airspace using the NASA UTM technology was a key safety component of this reference mission, since the flights were conducted beneath the landing approach to a heavily used runway. Comparison to autopilot tracking showed that UTM tracking accurately records the UAV position throughout the flight path.

Data products of NASA Goddard's LiDAR, hyperspectral, and thermal airborne imager (G-LiHT)

NASA Astrophysics Data System (ADS)

Corp, Lawrence A.; Cook, Bruce D.; McCorkel, Joel; Middleton, Elizabeth M.

2015-06-01

Scientists in the Biospheric Sciences Laboratory at NASA's Goddard Space Flight Center have undertaken a unique instrument fusion effort for an airborne package that integrates commercial off the shelf LiDAR, Hyperspectral, and Thermal components. G-LiHT is a compact, lightweight and portable system that can be used on a wide range of airborne platforms to support a number of NASA Earth Science research projects and space-based missions. G-LiHT permits simultaneous and complementary measurements of surface reflectance, vegetation structure, and temperature, which provide an analytical framework for the development of new algorithms for mapping plant species composition, plant functional types, biodiversity, biomass, carbon stocks, and plant growth. G-LiHT and its supporting database are designed to give scientists open access to the data that are needed to understand the relationship between ecosystem form and function and to stimulate the advancement of synergistic algorithms. This system will enhance our ability to design new missions and produce data products related to biodiversity and climate change. G-LiHT has been operational since 2011 and has been used to collect data for a number of NASA and USFS sponsored studies, including NASA's Carbon Monitoring System (CMS) and the American ICESat/GLAS Assessment of Carbon (AMIGA-Carb). These acquisitions target a broad diversity of forest communities and ecoregions across the United States and Mexico. Here, we will discuss the components of G-LiHT, their calibration and performance characteristics, operational implementation, and data processing workflows. We will also provide examples of higher level data products that are currently available.

Current Research in Lidar Technology Used for the Remote Sensing of Atmospheric Aerosols

PubMed Central

Comerón, Adolfo; Muñoz-Porcar, Constantino; Rocadenbosch, Francesc; Rodríguez-Gómez, Alejandro; Sicard, Michaël

2017-01-01

Lidars are active optical remote sensing instruments with unique capabilities for atmospheric sounding. A manifold of atmospheric variables can be profiled using different types of lidar: concentration of species, wind speed, temperature, etc. Among them, measurement of the properties of aerosol particles, whose influence in many atmospheric processes is important but is still poorly stated, stands as one of the main fields of application of current lidar systems. This paper presents a review on fundamentals, technology, methodologies and state-of-the art of the lidar systems used to obtain aerosol information. Retrieval of structural (aerosol layers profiling), optical (backscatter and extinction coefficients) and microphysical (size, shape and type) properties requires however different levels of instrumental complexity; this general outlook is structured following a classification that attends these criteria. Thus, elastic systems (detection only of emitted frequencies), Raman systems (detection also of Raman frequency-shifted spectral lines), high spectral resolution lidars, systems with depolarization measurement capabilities and multi-wavelength instruments are described, and the fundamentals in which the retrieval of aerosol parameters is based is in each case detailed. PMID:28632170

The Role of Interdisciplinary Earth Science in the Assessment of Regional Land Subsidence Hazards: Toward Sustainable Management of Global Land and Subsurface-Fluid Resources

NASA Astrophysics Data System (ADS)

Galloway, D. L.

2012-12-01

Land-level lowering or land subsidence is a consequence of many local- and regional-scale physical, chemical or biologic processes affecting soils and geologic materials. The principal processes can be natural or anthropogenic, and include consolidation or compaction, karst or pseudokarst, hydrocompaction of collapsible soils, mining, oxidation of organic soils, erosive piping, tectonism, and volcanism. In terms of affected area, there are two principal regional-scale anthropogenic processes—compaction of compressible subsurface materials owing to the extraction of subsurface fluids (principally groundwater, oil and gas) and oxidation and compaction accompanying drainage of organic soils—which cause significant hazards related to flooding and infrastructure damage that are amenable to resource management measures. The importance of even small magnitude (< 10 mm/yr) subsidence rates in coastal areas is amplified by its contribution to relative sea-level rise compared to estimated rates of rising eustatic sea levels (2-3 mm/yr) attributed to global climate change. Multi- or interdisciplinary [scientific] studies, including those focused on geodetic, geologic, geophysical, hydrologic, hydrogeologic, geomechanical, geochemical, and biologic factors, improve understanding of these subsidence processes. Examples include geodetic measurement and analysis techniques, such as Global Positioning System (GPS), Light Detection and Ranging (LiDAR) and Interferometric Synthetic Aperture Radar (InSAR), which have advanced our capabilities to detect, measure and monitor land-surface motion at multiple scales. Improved means for simulating aquifer-system and hydrocarbon-reservoir deformation, and the oxidation and compaction of organic soils are leading to refined predictive capabilities. The role of interdisciplinary earth science in improving the characterization of land subsidence attributed to subsurface fluid withdrawals and the oxidation and compaction of organic soils is examined. How these improved capabilities are translating into improved sustainable management of regional land and water resources in a few select areas worldwide are presented. The importance of incorporating these improved capabilities in coherent resource management strategies to control the depletion of resources and attendant hazards also are discussed.

Measurement of tropospheric aerosol in São Paulo area using a new upgraded Raman LIDAR system

NASA Astrophysics Data System (ADS)

Landulfo, Eduardo; Rodrigues, Patrícia F.; da Silva Lopes, Fábio Juliano; Bourayou, Riad

2012-11-01

Elastic backscatter LIDAR systems have been used to determine aerosol profile concentration in several areas such as weather, pollution and air quality monitoring. In order to determine the aerosol extinction and backscattering profiles, the Klett inversion method is largely used, but this method suffers from lack of information since there are two unknown variables to be determined using only one measured LIDAR signal, and assumption of the LIDAR ratio (the relation between the extinction and backscattering coefficients) is needed. When a Raman LIDAR system is used, the inelastic backscattering signal is affected by aerosol extinction but not by aerosol backscatter, which allows this LIDAR to uniquely determine extinction and backscattering coefficients without any assumptions or any collocated instruments. The MSP-LIDAR system, set-up in a highly dense suburban area in the city of São Paulo, has been upgraded to a Raman LIDAR, and in its actual 6-channel configuration allows it to monitor elastic backscatter at 355 and 532 nm together with nitrogen and water vapor Raman backscatters at 387nm and 608 nm and 408nm and 660 nm, respectively. Thus, the measurements of aerosol backscattering, extinction coefficients and water vapor mixing ratio in the Planetary Boundary Layer (PBL) are becoming available. The system will provide the important meteorological parameters such as Aerosol Optical Depth (AOD) and will be used for the study of aerosol variations in lower troposphere over the city of São Paulo, air quality monitoring and for estimation of humidity impact on the aerosol optical properties, without any a priori assumption. This study will present the first results obtained with this upgraded LIDAR system, demonstrating the high quality of obtained aerosol and water vapor data. For that purpose, we compared the data obtained with the new MSP-Raman LIDAR with a mobile Raman LIDAR collocated at the Center for Lasers and Applications, Nuclear and Energy Research Institute in São Paulo and radiosonde data from Campo de Marte Airport, in São Paulo.

Modeling the Performance of Direct-Detection Doppler Lidar Systems in Real Atmospheres

NASA Technical Reports Server (NTRS)

McGill, Matthew J.; Hart, William D.; McKay, Jack A.; Spinhirne, James D.

1999-01-01

Previous modeling of the performance of spaceborne direct-detection Doppler lidar systems has assumed extremely idealized atmospheric models. Here we develop a technique for modeling the performance of these systems in a more realistic atmosphere, based on actual airborne lidar observations. The resulting atmospheric model contains cloud and aerosol variability that is absent in other simulations of spaceborne Doppler lidar instruments. To produce a realistic simulation of daytime performance, we include solar radiance values that are based on actual measurements and are allowed to vary as the viewing scene changes. Simulations are performed for two types of direct-detection Doppler lidar systems: the double-edge and the multi-channel techniques. Both systems were optimized to measure winds from Rayleigh backscatter at 355 nm. Simulations show that the measurement uncertainty during daytime is degraded by only about 10-20% compared to nighttime performance, provided a proper solar filter is included in the instrument design.

Modeling the performance of direct-detection Doppler lidar systems including cloud and solar background variability.

PubMed

McGill, M J; Hart, W D; McKay, J A; Spinhirne, J D

1999-10-20

Previous modeling of the performance of spaceborne direct-detection Doppler lidar systems assumed extremely idealized atmospheric models. Here we develop a technique for modeling the performance of these systems in a more realistic atmosphere, based on actual airborne lidar observations. The resulting atmospheric model contains cloud and aerosol variability that is absent in other simulations of spaceborne Doppler lidar instruments. To produce a realistic simulation of daytime performance, we include solar radiance values that are based on actual measurements and are allowed to vary as the viewing scene changes. Simulations are performed for two types of direct-detection Doppler lidar system: the double-edge and the multichannel techniques. Both systems were optimized to measure winds from Rayleigh backscatter at 355 nm. Simulations show that the measurement uncertainty during daytime is degraded by only approximately 10-20% compared with nighttime performance, provided that a proper solar filter is included in the instrument design.

Design validation of an eye-safe scanning aerosol lidar with the Center for Lidar and Atmospheric Sciences Students (CLASS) at Hampton University

NASA Astrophysics Data System (ADS)

Richter, Dale A.; Higdon, N. S.; Ponsardin, Patrick L.; Sanchez, David; Chyba, Thomas H.; Temple, Doyle A.; Gong, Wei; Battle, Russell; Edmondson, Mika; Futrell, Anne; Harper, David; Haughton, Lincoln; Johnson, Demetra; Lewis, Kyle; Payne-Baggott, Renee S.

2002-01-01

ITTs Advanced Engineering and Sciences Division and the Hampton University Center for Lidar and Atmospheric Sciences Students (CLASS) team have worked closely to design, fabricate and test an eye-safe, scanning aerosol-lidar system that can be safely deployed and used by students form a variety of disciplines. CLASS is a 5-year undergraduate- research training program funded by NASA to provide hands-on atmospheric-science and lidar-technology education. The system is based on a 1.5 micron, 125 mJ, 20 Hz eye-safe optical parametric oscillator (OPO) and will be used by the HU researchers and students to evaluate the biological impact of aerosols, clouds, and pollution a variety of systems issues. The system design tasks we addressed include the development of software to calculate eye-safety levels and to model lidar performance, implementation of eye-safety features in the lidar transmitter, optimization of the receiver using optical ray tracing software, evaluation of detectors and amplifiers in the near RI, test of OPO and receiver technology, development of hardware and software for laser and scanner control and video display of the scan region.

Spaceborne Lidar in the Study of Marine Systems.

PubMed

Hostetler, Chris A; Behrenfeld, Michael J; Hu, Yongxiang; Hair, Johnathan W; Schulien, Jennifer A

2018-01-03

Satellite passive ocean color instruments have provided an unbroken ∼20-year record of global ocean plankton properties, but this measurement approach has inherent limitations in terms of spatial-temporal sampling and ability to resolve vertical structure within the water column. These limitations can be addressed by coupling ocean color data with measurements from a spaceborne lidar. Airborne lidars have been used for decades to study ocean subsurface properties, but recent breakthroughs have now demonstrated that plankton properties can be measured with a satellite lidar. The satellite lidar era in oceanography has arrived. Here, we present a review of the lidar technique, its applications in marine systems, a perspective on what can be accomplished in the near future with an ocean- and atmosphere-optimized satellite lidar, and a vision for a multiplatform virtual constellation of observational assets that would enable a three-dimensional reconstruction of global ocean ecosystems.

Spaceborne Lidar in the Study of Marine Systems

NASA Astrophysics Data System (ADS)

Hostetler, Chris A.; Behrenfeld, Michael J.; Hu, Yongxiang; Hair, Johnathan W.; Schulien, Jennifer A.

2018-01-01

Satellite passive ocean color instruments have provided an unbroken ˜20-year record of global ocean plankton properties, but this measurement approach has inherent limitations in terms of spatial-temporal sampling and ability to resolve vertical structure within the water column. These limitations can be addressed by coupling ocean color data with measurements from a spaceborne lidar. Airborne lidars have been used for decades to study ocean subsurface properties, but recent breakthroughs have now demonstrated that plankton properties can be measured with a satellite lidar. The satellite lidar era in oceanography has arrived. Here, we present a review of the lidar technique, its applications in marine systems, a perspective on what can be accomplished in the near future with an ocean- and atmosphere-optimized satellite lidar, and a vision for a multiplatform virtual constellation of observational assets that would enable a three-dimensional reconstruction of global ocean ecosystems.

Comments on: Accuracy of Raman Lidar Water Vapor Calibration and its Applicability to Long-Term Measurements

NASA Technical Reports Server (NTRS)

Whiteman, David N.; Venable, Demetrius; Landulfo, Eduardo

2012-01-01

In a recent publication, LeBlanc and McDermid proposed a hybrid calibration technique for Raman water vapor lidar involving a tungsten lamp and radiosondes. Measurements made with the lidar telescope viewing the calibration lamp were used to stabilize the lidar calibration determined by comparison with radiosonde. The technique provided a significantly more stable calibration constant than radiosondes used alone. The technique involves the use of a calibration lamp in a fixed position in front of the lidar receiver aperture. We examine this configuration and find that such a configuration likely does not properly sample the full lidar system optical efficiency. While the technique is a useful addition to the use of radiosondes alone for lidar calibration, it is important to understand the scenarios under which it will not provide an accurate quantification of system optical efficiency changes. We offer examples of these scenarios.

Comparison between two lidar methods to retrieve microphysical properties of liquid-water clouds

NASA Astrophysics Data System (ADS)

Jimenez, Cristofer; Ansmann, Albert; Donovan, David; Engelmann, Ronny; Schmidt, Jörg; Wandinger, Ulla

2018-04-01

Since 2010, the Raman dual-FOV lidar system permits the retrieval of microphysical properties of liquid-water clouds during nighttime. A new robust lidar depolarization approach was recently introduced, which permits the retrieval of these properties as well, with high temporal resolution and during daytime. To implement this approach, the lidar system was upgraded, by adding a three channel depolarization receiver. The first preliminary retrieval results and a comparison between both methods is presented.

Fine-scale ignimbrite morphology revealed in LiDAR at Crater Lake, OR

NASA Astrophysics Data System (ADS)

Robinson, J. E.; Bacon, C. R.; Wright, H. M.

2011-12-01

Mount Mazama erupted ~7,700 years ago resulting in the collapse of Crater Lake caldera, ash fall across the Pacific Northwest, and emplacement of compositionally zoned ignimbrite. Early climactic ignimbrite contains uniform rhyodacitic pumice and traveled far from the vent, whereas late, less mobile ignimbrite is dominated by crystal-rich andesitic scoria and mafic crystal mush. Funded by the USGS, NPS, and FHWA, the DOGAMI-led Oregon LiDAR Consortium contracted with Watershed Services to collect ~800 km2 of LiDAR over Crater Lake National Park from Aug 2010 to Sept 2010. Ground laser returns have an average density of 1.63 returns/m2 over the heavily forested area of interest. The data have a lateral RMSE and vertical accuracy of 0.05 m. A bare earth terrain model allows a virtual removal of the forest, revealing fine-scale surface morphology, notably in the climactic ignimbrite. Secondary pyroclastic flows, explosion craters, erosion by water, and compaction-related deformation modified the originally smooth ignimbrite surface. Distinct pyroclastic flow fronts are evident in the LiDAR in Annie Creek valley. Leveed flows stand approximately 5 m above the lower ignimbrite surface, and individual toes are about 1-2 m high. Preliminary field checking indicates that rhyodacitic pumice dominates the lower ignimbrite surface, but the leveed flows are a subequal mix of locally oxidized rhyodacitic pumice and andesitic scoria. We hypothesize that these deposits were secondary pyroclastic flows formed by gravitational failure of late ignimbrite. In the Castle Creek valley, is a 2-meter collapse scarp that may have spawned a small secondary pyroclastic flow; several such headwall scarps are present in Sand Creek valley. Differential compaction features are common in many thick ignimbrites. We suggest this caused the deformation of the ignimbrite apparent in the LiDAR. In Annie Creek valley are a series of flow parallel asymmetric ridges, with shallower slopes toward the valley center, in the surface of the rhyodacitic ignimbrite. The ridges are 1-2 m high, and have a variable wavelength averaging 60 m. We hypothesize that this terrain is a series of antithetic faults due to downbending towards the thickest part of the ignimbrite. The ignimbrite near the Pumice Desert is likely over 100 m thick. Here, cracks positioned on topographic highs or at breaks in slope are 50 m to 800 m long and up to 30 m wide. The cracks open towards the thickest part of the ignimbrite in the downslope direction. They appear to be tension fractures that opened because of differential compaction of the ignimbrite. Breakaway fractures mark where ignimbrite thickness abruptly decreases laterally, such as north-northeast of the caldera and at valley margins. Some fractures show evidence of water erosion during formation of fractures. On the lee side of Timber Crater, north of Crater Lake, is a series of N-S trending ribs composed of pumice fall from the climactic eruption deposited on glaciated andesite lava. Timber Crater lies on the main dispersal axis of the pumice fall. We suggest that high-energy pyroclastic flows encountered topographic bumps on the flanks of Timber Crater. This affected flow turbulence causing linear troughs to erode into the fall deposit and leaving pumice-fall ribs.

The Multi-Center Airborne Coherent Atmospheric Wind Sensor: Recent Measurements and Future Applications

NASA Technical Reports Server (NTRS)

Rothermel, Jeffry; Cutten, Dean R.; Hardesty, R. Michael; Howell, James N.; Darby, Lisa S.; Tratt, David M.; Menzies, Robert T.

1999-01-01

The coherent Doppler lidar, when operated from an airborne platform, offers a unique measurement capability for study of atmospheric dynamical and physical properties. This is especially true for scientific objectives requiring measurements in optically-clear air, where other remote sensing technologies such as Doppler radar are at a disadvantage in terms of spatial resolution and coverage. Recent experience suggests airborne coherent Doppler lidar can yield unique wind measurements of--and during operation within--extreme weather phenomena. This paper presents the first airborne coherent Doppler lidar measurements of hurricane wind fields. The lidar atmospheric remote sensing groups of National Aeronautics and Space Administration (NASA) Marshall Space Flight Center, National Oceanic and Atmospheric Administration (NOAA) Environmental Technology Laboratory, and Jet Propulsion Laboratory jointly developed an airborne lidar system, the Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS). The centerpiece of MACAWS is the lidar transmitter from the highly successful NOAA Windvan. Other field-tested lidar components have also been used, when feasible, to reduce costs and development time. The methodology for remotely sensing atmospheric wind fields with scanning coherent Doppler lidar was demonstrated in 1981; enhancements were made and the system was reflown in 1984. MACAWS has potentially greater scientific utility, compared to the original airborne scanning lidar system, owing to a factor of approx. 60 greater energy-per-pulse from the NOAA transmitter. MACAWS development was completed and the system was first flown in 1995. Following enhancements to improve performance, the system was re-flown in 1996 and 1998. The scientific motivation for MACAWS is three-fold: obtain fundamental measurements of subgrid scale (i.e., approx. 2-200 km) processes and features which may be used to improve parameterizations in hydrological, climate, and general/regional circulation models; obtain similar datasets to improve understanding and predictive capabilities for similarly-scaled processes and features; and simulate and validate the performance of prospective satellite Doppler lidars for global tropospheric wind measurement.

Doppler lidar power, aperture diameter, and FFT size trade-off study

NASA Astrophysics Data System (ADS)

Chester, David B.; Budge, Scott E.

2017-05-01

In the design or selection of a Doppler lidar instrument for a spacecraft landing system, it is important to evaluate the balance between performance requirements and cost, weight, and power consumption. Leveraging the capability of LadarSIM, a trade-off study was performed to evaluate the interaction between the laser transmission power, aperture diameter, and FFT size in a Doppler lidar system. For this study the probabilities of detection and false alarm were calculated using LadarSIM to simulate FMCW lidar systems with varying power, aperture diameter, and FFT size. This paper reports the results of this trade-off study.

Automated integration of lidar into the LANDFIRE product suite

USGS Publications Warehouse

Peterson, Birgit; Nelson, Kurtis; Seielstad, Carl; Stoker, Jason M.; Jolly, W. Matt; Parsons, Russell

2015-01-01

Accurate information about three-dimensional canopy structure and wildland fuel across the landscape is necessary for fire behaviour modelling system predictions. Remotely sensed data are invaluable for assessing these canopy characteristics over large areas; lidar data, in particular, are uniquely suited for quantifying three-dimensional canopy structure. Although lidar data are increasingly available, they have rarely been applied to wildland fuels mapping efforts, mostly due to two issues. First, the Landscape Fire and Resource Planning Tools (LANDFIRE) program, which has become the default source of large-scale fire behaviour modelling inputs for the US, does not currently incorporate lidar data into the vegetation and fuel mapping process because spatially continuous lidar data are not available at the national scale. Second, while lidar data are available for many land management units across the US, these data are underutilized for fire behaviour applications. This is partly due to a lack of local personnel trained to process and analyse lidar data. This investigation addresses these issues by developing the Creating Hybrid Structure from LANDFIRE/lidar Combinations (CHISLIC) tool. CHISLIC allows individuals to automatically generate a suite of vegetation structure and wildland fuel parameters from lidar data and infuse them into existing LANDFIRE data sets. CHISLIC will become available for wider distribution to the public through a partnership with the U.S. Forest Service’s Wildland Fire Assessment System (WFAS) and may be incorporated into the Wildland Fire Decision Support System (WFDSS) with additional design and testing. WFAS and WFDSS are the primary systems used to support tactical and strategic wildland fire management decisions.

Differential Absorption Lidar (DIAL) Measurements from Air and Space

NASA Technical Reports Server (NTRS)

Browell, E. V.; Ismail, S.; Grant, W. B.

1998-01-01

Differential absorption lidar (DIAL) systems have been used for the measurement of ozone, water vapor, and aerosols from aircraft platforms for over 18 years, yielding new insights into atmospheric chemistry, composition, and dynamics in large-scale field experiments conducted all over the world. The successful deployment of the lidar in-space technology experiment (LITE) in September 1994 demonstrated that space-based lidars can also collect valuable information on the global atmosphere. This paper reviews some of the contributions of the NASA Langley Research Center's airborne ozone and water vapor DIAL systems and space-based LITE system to the understanding of the atmosphere and discusses the feasibility and advantages of putting DIAL systems in space for routine atmospheric measurements of ozone and/or water vapor and aerosols and clouds. The technology and applications of the differential absorption lidar (DIAL) technique have progressed significantly since the first DIAL measurements of Schotland, and airborne DIAL measurements of ozone and water vapor are frequently being made in a wide range of field experiments. In addition, plans are underway to develop DIAL systems for use on satellites for continuous global measurements. This paper will highlight the history of airborne lidar and DIAL systems, summarize the major accomplishments of the NASA Langley DIAL program, and discuss specifications and goals for DIAL systems in space.

Integrating forest inventory and analysis data into a LIDAR-based carbon monitoring system

Treesearch

Kristofer D. Johnson; Richard Birdsey; Andrew O Finley; Anu Swantaran; Ralph Dubayah; Craig Wayson; Rachel Riemann

2014-01-01

Forest Inventory and Analysis (FIA) data may be a valuable component of a LIDAR-based carbon monitoring system, but integration of the two observation systems is not without challenges. To explore integration methods, two wall-to-wall LIDAR-derived biomass maps were compared to FIA data at both the plot and county levels in Anne Arundel and Howard Counties in Maryland...

Integrated remote sensing and visualization (IRSV) system for transportation infrastructure operations and management, phase one, volume 3 : use of scanning LiDAR in structural evaluation of bridges.

DOT National Transportation Integrated Search

2009-12-01

This volume introduces several applications of remote bridge inspection technologies studied in : this Integrated Remote Sensing and Visualization (IRSV) study using ground-based LiDAR : systems. In particular, the application of terrestrial LiDAR fo...

Airborne Wind Profiling Algorithm for Doppler Wind LIDAR

NASA Technical Reports Server (NTRS)

Kavaya, Michael J. (Inventor); Beyon, Jeffrey Y. (Inventor); Koch, Grady J. (Inventor)

2015-01-01

Systems, methods, and devices of the present invention enable airborne Doppler Wind LIDAR system measurements and INS/GPS measurements to be combined to estimate wind parameters and compensate for instrument misalignment. In a further embodiment, the wind speed and wind direction may be computed based on two orthogonal line-of-sight LIDAR returns.

Telescope aperture optimization for spacebased coherent wind lidar

NASA Astrophysics Data System (ADS)

Ge, Xian-ying; Zhu, Jun; Cao, Qipeng; Zhang, Yinchao; Yin, Huan; Dong, Xiaojing; Wang, Chao; Zhang, Yongchao; Zhang, Ning

2015-08-01

Many studies have indicated that the optimum measurement approach for winds from space is a pulsed coherent wind lidar, which is an active remote sensing tool with the characteristics that high spatial and temporal resolutions, real-time detection, high mobility, facilitated control and so on. Because of the significant eye safety, efficiency, size, and lifetime advantage, 2μm wavelength solid-state laser lidar systems have attracted much attention in spacebased wind lidar plans. In this paper, the theory of coherent detection is presented and a 2μm wavelength solid-state laser lidar system is introduced, then the ideal aperture is calculated from signal-to-noise(SNR) view at orbit 400km. However, considering real application, even if the lidar hardware is perfectly aligned, the directional jitter of laser beam, the attitude change of the lidar in the long round trip time of the light from the atmosphere and other factors can bring misalignment angle. So the influence of misalignment angle is considered and calculated, and the optimum telescope diameter(0.45m) is obtained as the misalignment angle is 4 μrad. By the analysis of the optimum aperture required for spacebased coherent wind lidar system, we try to present the design guidance for the telescope.

Lidar-based mapping of flood control levees in south Louisiana

USGS Publications Warehouse

Thatcher, Cindy A.; Lim, Samsung; Palaseanu-Lovejoy, Monica; Danielson, Jeffrey J.; Kimbrow, Dustin R.

2016-01-01

Flood protection in south Louisiana is largely dependent on earthen levees, and in the aftermath of Hurricane Katrina the state’s levee system has received intense scrutiny. Accurate elevation data along the levees are critical to local levee district managers responsible for monitoring and maintaining the extensive system of non-federal levees in coastal Louisiana. In 2012, high resolution airborne lidar data were acquired over levees in Lafourche Parish, Louisiana, and a mobile terrestrial lidar survey was conducted for selected levee segments using a terrestrial lidar scanner mounted on a truck. The mobile terrestrial lidar data were collected to test the feasibility of using this relatively new technology to map flood control levees and to compare the accuracy of the terrestrial and airborne lidar. Metrics assessing levee geometry derived from the two lidar surveys are also presented as an efficient, comprehensive method to quantify levee height and stability. The vertical root mean square error values of the terrestrial lidar and airborne lidar digital-derived digital terrain models were 0.038 m and 0.055 m, respectively. The comparison of levee metrics derived from the airborne and terrestrial lidar-based digital terrain models showed that both types of lidar yielded similar results, indicating that either or both surveying techniques could be used to monitor geomorphic change over time. Because airborne lidar is costly, many parts of the USA and other countries have never been mapped with airborne lidar, and repeat surveys are often not available for change detection studies. Terrestrial lidar provides a practical option for conducting repeat surveys of levees and other terrain features that cover a relatively small area, such as eroding cliffs or stream banks, and dunes.

Scanning lidar fluorosensor for remote diagnostic of surfaces

NASA Astrophysics Data System (ADS)

Caneve, Luisa; Colao, Francesco; Fantoni, Roberta; Fiorani, Luca

2013-08-01

Scanning hyperspectral systems based on laser induced fluorescence (LIF) have been developed and realized at the ENEA allowing to obtain information of analytical and qualitative interest on different materials by the study of the emission of fluorescence. This technique, for a surface analysis, is fast, remote, not invasive and specific. A new compact setup capable of fast 2D monochromatic images acquisition on up to 90 different spectral channels in the visible/UV range will be presented. It has been recently built with the aim to increase the performances in terms of space resolution, time resolved capabilities and data acquisition speed. Major achievements have been reached by a critical review of the optical design. The results recently obtained with in-situ measurements of interest for applications in the field of cultural heritage will be shown. 2001 Elsevier Science. All rights reserved

Lidar system for air-pollution monitoring over urban areas

NASA Astrophysics Data System (ADS)

Moskalenko, Irina V.; Shcheglov, Djolinard A.; Molodtsov, Nikolai A.

1997-05-01

The atmospheric environmental situation over the urban area of a large city is determined by a complex combination of anthropogenic pollution and meteorological factors. The efficient way to provide three-dimensional mapping of gaseous pollutants over wide areas is utilization of lidar systems employing tunable narrowband transmitters. The paper presented describes activity of RRC 'Kurchatov Institute' in the field of lidar atmospheric monitoring. The project 'mobile remote sensing system based on tunable laser transmitter for environmental monitoring' is developed under financial support of International Scientific and Technology Center (Moscow). The objective of the project is design, construction and field testing of a DIAL-technique system. The lidar transmitter consists of an excimer laser pumping dye laser, BBO crystal frequency doubler, and scanning flat mirror. Sulfur dioxide and atomic mercury have been selected as pollutants for field tests of the lidar system under development. A recent large increase in Moscow traffic stimulated taking into consideration also the remote sensing of lower troposphere ozone because of the photochemical smog problem. The status of the project is briefly discussed. The current activity includes also collecting of environmental data relevant to lidar remote sensing. Main attention is paid to pollutant concentration levels over Moscow city and Moscow district areas.

A novel high-resolution chaotic lidar with optical injection to chaotic laser diode

NASA Astrophysics Data System (ADS)

Wang, Yun-cai; Wang, An-bang

2008-03-01

A novel chaotic lidar with high resolution is proposed and studied theoretically. In chaotic lidar system, the chaotic laser emitted from chaotic laser diode is split into two beams: the probe and the reference light. The ranging is achieved by correlating the reference waveform with the delayed probe waveform backscattered from the target. In chaotic lidar systems presented previously, the chaotic signal source is laser diode with optical feedback or with optical injection by another one. The ranging resolution is limited by the bandwidth of chaotic laser which determined by the configuration of chaotic signal source. We proposed a novel chaotic lidar which ranging resolution is enhanced significantly by external optical injected chaotic laser diode. With the bandwidth-enhanced chaotic laser, the range resolution of the chaotic lidar system with optical injection is roughly two times compared with that of without optical injection. The resolution increases with injection strength increasing in a certain frequency detuning range.

Transportable Rayleigh/Raman lidar for aerosol and water vapor profiling

NASA Astrophysics Data System (ADS)

Congeduti, Fernando; D'Aulerio, P.; Casadio, S.; Baldetti, P.; Belardinelli, F.

2001-01-01

A nighttime operating Raman/Rayleigh/Mie lidar system for the measurement of profiles of the water vapor mixing ratio and the aerosol backscatter ratio is described. The transmitter utilizes two laser beam at 532 nm and 355 nm from a Nd:YAG pulsed laser and the receiver consists of three Newtonian telescopes. Optical fibers carry the signal to the detectors. The system, which is installed in two containers, is transportable. Data are recorded with resolutions of 75-m in altitude and 1-min in time. Water vapor profiles from 200 m above the lidar altitude up to the upper troposphere and aerosol profiles form 500 m up to the lower stratosphere were obtained also at the lowest resolution. The lidar was deployed and used in the 'Target Area of the Lago Maggiore' during the MAP-SOP international campaign. Measurements taken during that campaign are reported to show the lidar performance. Improvements of the system by employing an array of nine 50-cm diameter telescopes are planned. These should effectively enhance the lidar performance.

Applications of KHZ-CW Lidar in Ecological Entomology

NASA Astrophysics Data System (ADS)

Malmqvist, Elin; Brydegaard, Mikkel

2016-06-01

The benefits of kHz lidar in ecological entomology are explained. Results from kHz-measurements on insects, carried out with a CW-lidar system, employing the Scheimpflug principle to obtain range resolution, are presented. A method to extract insect events and analyze the large amount of lidar data is also described.

Lamp mapping technique for independent determination of the water vapor mixing ratio calibration factor for a Raman lidar system

NASA Astrophysics Data System (ADS)

Venable, Demetrius D.; Whiteman, David N.; Calhoun, Monique N.; Dirisu, Afusat O.; Connell, Rasheen M.; Landulfo, Eduardo

2011-08-01

We have investigated a technique that allows for the independent determination of the water vapor mixing ratio calibration factor for a Raman lidar system. This technique utilizes a procedure whereby a light source of known spectral characteristics is scanned across the aperture of the lidar system's telescope and the overall optical efficiency of the system is determined. Direct analysis of the temperature-dependent differential scattering cross sections for vibration and vibration-rotation transitions (convolved with narrowband filters) along with the measured efficiency of the system, leads to a theoretical determination of the water vapor mixing ratio calibration factor. A calibration factor was also obtained experimentally from lidar measurements and radiosonde data. A comparison of the theoretical and experimentally determined values agrees within 5%. We report on the sensitivity of the water vapor mixing ratio calibration factor to uncertainties in parameters that characterize the narrowband transmission filters, the temperature-dependent differential scattering cross section, and the variability of the system efficiency ratios as the lamp is scanned across the aperture of the telescope used in the Howard University Raman Lidar system.

2.5 MHz Line-Width High-energy, 2 Micrometer Coherent Wind Lidar Transmitter

NASA Technical Reports Server (NTRS)

Petros, Mulugeta; Yu, Jirong; Trieu, Bo; Bai, Yingxin; Petzar, Paul; Singh, Upendra N.; Reithmaier, Karl

2007-01-01

2 micron solid-state lasers are the primary choice for coherent Doppler wind detection. As wind lidars, they are used for wake vortex and clear air turbulence detection providing air transport safety. In addition, 2 micron lasers are one of the candidates for CO2 detection lidars. The rich CO2 absorption line around 2 micron, combined with the long upper state life of time, has made Ho based 2 micron lasers a viable candidate for CO2 sensing DIAL instrument. The design and fabrication of a compact coherent laser radar transmitter for Troposphere wind sensing is under way. This system is hardened for ground as well as airborne applications. As a transmitter for a coherent wind lidar, this laser has stringent spectral line width and beam quality requirements. Although the absolute wavelength does not have to be fixed for wind detection, to maximize return signal, the output wavelength should avoid atmospheric CO2 and H2O absorption lines. The base line laser material is Ho:Tm:LuLF which is an isomorph of Ho:Tm:YLF. LuLF produces 20% more output power than Ho:Tm:YLF. In these materials the Tm absorption cross-section, the Ho emission cross-section, the Tm to Ho energy transfer parameters and the Ho (sup 5) I (sub 7) radiative life time are all identical. However, the improved performance of the LuLF is attributed to the lower thermal population in the (sup 5) I (sub 8) manifold. It also provides higher normal mode to Q-switch conversion than YLF at high pump energy indicating a lower up-conversion. The laser architecture is composed of a seed laser, a ring oscillator, and a double pass amplifier. The seed laser is a single longitudinal mode with a line width of 13 KHz. The 100mJ class oscillator is stretched to 3 meters to accommodate the line-width requirement without compromising the range resolution of the instrument. The amplifier is double passed to produce greater than 300mJ energy.

Simulation of a Doppler lidar system for autonomous navigation and hazard avoidance during planetary landing

NASA Astrophysics Data System (ADS)

Budge, Scott E.; Chester, David B.

2016-05-01

The latest mission proposals for exploration of solar system bodies require accurate position and velocity data during the descent phase in order to ensure safe, soft landing at the pre-designated sites. During landing maneuvers, the accuracy of the on-board inertial measurement unit (IMU) may not be reliable due to drift over extended travel times to destinations. NASA has proposed an advanced Doppler lidar system with multiple beams that can be used to accurately determine attitude and position of the landing vehicle during descent, and to detect hazards that might exist in the landing area. In order to assess the effectiveness of such a Doppler lidar landing system, it is valuable to simulate the system with different beam numbers and configurations. In addition, the effectiveness of the system to detect and map potential landing hazards must be understood. This paper reports the simulated system performance for a proposed multi-beam Doppler lidar using the LadarSIM system simulation software. Details of the simulation methods are given, as well as lidar performance parameters such as range and velocity accuracy, detection and false alarm rates, and examples of the Doppler lidars ability to detect and characterize simulated hazards in the landing site. The simulation includes modulated pulse generation and coherent detection methods, beam footprint simulation, beam scanning, and interaction with terrain.

Lidar point density analysis: implications for identifying water bodies

USGS Publications Warehouse

Worstell, Bruce B.; Poppenga, Sandra K.; Evans, Gayla A.; Prince, Sandra

2014-01-01

Most airborne topographic light detection and ranging (lidar) systems operate within the near-infrared spectrum. Laser pulses from these systems frequently are absorbed by water and therefore do not generate reflected returns on water bodies in the resulting void regions within the lidar point cloud. Thus, an analysis of lidar voids has implications for identifying water bodies. Data analysis techniques to detect reduced lidar return densities were evaluated for test sites in Blackhawk County, Iowa, and Beltrami County, Minnesota, to delineate contiguous areas that have few or no lidar returns. Results from this study indicated a 5-meter radius moving window with fewer than 23 returns (28 percent of the moving window) was sufficient for delineating void regions. Techniques to provide elevation values for void regions to flatten water features and to force channel flow in the downstream direction also are presented.

Polarization effects on hard target calibration of lidar systems

NASA Technical Reports Server (NTRS)

Kavaya, Michael J.

1987-01-01

The theory of hard target calibration of lidar backscatter data, including laboratory measurements of the pertinent target reflectance parameters, is extended to include the effects of polarization of the transmitted and received laser radiation. The bidirectional reflectance-distribution function model of reflectance is expanded to a 4 x 4 matrix allowing Mueller matrix and Stokes vector calculus to be employed. Target reflectance parameters for calibration of lidar backscatter data are derived for various lidar system polarization configurations from integrating sphere and monostatic reflectometer measurements. It is found that correct modeling of polarization effects is mandatory for accurate calibration of hard target reflectance parameters and, therefore, for accurate calibration of lidar backscatter data.

Performance modelling of miniaturized flash-imaging lidars for future mars exploration missions

NASA Astrophysics Data System (ADS)

Mitev, V.; Pollini, A.; Haesler, J.; Pereira do Carmo, João.

2017-11-01

Future planetary exploration missions require the support of 3D vision in the GN&C during key spacecraft's proximity phases, namely: i) spacecraft precision and soft Landing on the planet's surface; ii) Rendezvous and Docking (RVD) between a Sample Canister (SC) and an orbiter spacecraft; iii) Rover Navigation (RN) on planetary surface. The imaging LiDARs are among the best candidate for such tasks [1-3]. The combination of measurement requirements and environmental conditions seems to find its optimum in the flash 3D LiDAR architecture. Here we present key steps is the evaluation of novelty light detectors and MOEMS (Micro-Opto- Electro-Mechanical Systems) technologies with respect to LiDAR system performance and miniaturization. The objectives of the project MILS (Miniaturized Imaging LiDAR System, Phase 1) concentrated on the evaluation of novel detection and scanning technologies for the miniaturization of 3D LiDARs intended for planetary mission. Preliminary designs for an elegant breadboard (EBB) for the three tasks stated above (Landing, RVD and RN) were proposed, based on results obtained with a numerical model developed in the project and providing the performances evaluation of imaging LiDARs.

Structure-From-Motion in 3D Space Using 2D Lidars

PubMed Central

Choi, Dong-Geol; Bok, Yunsu; Kim, Jun-Sik; Shim, Inwook; Kweon, In So

2017-01-01

This paper presents a novel structure-from-motion methodology using 2D lidars (Light Detection And Ranging). In 3D space, 2D lidars do not provide sufficient information for pose estimation. For this reason, additional sensors have been used along with the lidar measurement. In this paper, we use a sensor system that consists of only 2D lidars, without any additional sensors. We propose a new method of estimating both the 6D pose of the system and the surrounding 3D structures. We compute the pose of the system using line segments of scan data and their corresponding planes. After discarding the outliers, both the pose and the 3D structures are refined via nonlinear optimization. Experiments with both synthetic and real data show the accuracy and robustness of the proposed method. PMID:28165372

Characterization of convection-related parameters by Raman lidar: Selected case studies from the convective and orographically-induced precipitation study

NASA Astrophysics Data System (ADS)

Di Girolamo, Paolo; Summa, Donato; Stelitano, Dario

2013-05-01

An approach to determine the convective available potential energy (CAPE) and the convective inhibition (CIN) based on the use of data from a Raman lidar system is illustrated in this work. The use of Raman lidar data allows to provide high temporal resolution measurements (5 min) of CAPE and CIN and follow their evolution over extended time periods covering the full cycle of convective activity. Lidar-based measurements of CAPE and CIN are obtained from Raman lidar measurements of the temperature and water vapor mixing ratio profiles and the surface measurements of temperature, pressure and dew point temperature provided by a surface weather station. The approach is applied to the data collected by the Raman lidar system BASIL in the frame of COPS. Attention was focused on 15 July and 25-26 July 2007. Lidar-based measurements are in good agreement with simultaneous measurements from radiosondes and with estimates from different mesoscale models.

Comparison of Aerosol Optical Properties and Water Vapor Among Ground and Airborne Lidars and Sun Photometers During TARFOX

NASA Technical Reports Server (NTRS)

Ferrare, R.; Ismail, S.; Browell, E.; Brackett, V.; Clayton, M.; Kooi, S.; Melfi, S. H.; Whiteman, D.; Schwemmer, G.; Evans, K.;

Lidar Systems for Precision Navigation and Safe Landing on Planetary Bodies

NASA Technical Reports Server (NTRS)

Amzajerdian, Farzin; Pierrottet, Diego F.; Petway, Larry B.; Hines, Glenn D.; Roback, Vincent E.

2011-01-01

The ability of lidar technology to provide three-dimensional elevation maps of the terrain, high precision distance to the ground, and approach velocity can enable safe landing of robotic and manned vehicles with a high degree of precision. Currently, NASA is developing novel lidar sensors aimed at needs of future planetary landing missions. These lidar sensors are a 3-Dimensional Imaging Flash Lidar, a Doppler Lidar, and a Laser Altimeter. The Flash Lidar is capable of generating elevation maps of the terrain that indicate hazardous features such as rocks, craters, and steep slopes. The elevation maps collected during the approach phase of a landing vehicle, at about 1 km above the ground, can be used to determine the most suitable safe landing site. The Doppler Lidar provides highly accurate ground relative velocity and distance data allowing for precision navigation to the landing site. Our Doppler lidar utilizes three laser beams pointed to different directions to measure line of sight velocities and ranges to the ground from altitudes of over 2 km. Throughout the landing trajectory starting at altitudes of about 20 km, the Laser Altimeter can provide very accurate ground relative altitude measurements that are used to improve the vehicle position knowledge obtained from the vehicle navigation system. At altitudes from approximately 15 km to 10 km, either the Laser Altimeter or the Flash Lidar can be used to generate contour maps of the terrain, identifying known surface features such as craters, to perform Terrain relative Navigation thus further reducing the vehicle s relative position error. This paper describes the operational capabilities of each lidar sensor and provides a status of their development. Keywords: Laser Remote Sensing, Laser Radar, Doppler Lidar, Flash Lidar, 3-D Imaging, Laser Altimeter, Precession Landing, Hazard Detection

Performance analysis and technical assessment of coherent lidar systems for airborne wind shear detection

NASA Technical Reports Server (NTRS)

Huffaker, R. Milton; Targ, Russell

1988-01-01

Detailed computer simulations of the lidar wind-measuring process have been conducted to evaluate the use of pulsed coherent lidar for airborne windshear monitoring. NASA data fields for an actual microburst event were used in the simulation. Both CO2 and Ho:YAG laser lidar systems performed well in the microburst test case, and were able to measure wind shear in the severe weather of this wet microburst to ranges in excess of 1.4 km. The consequent warning time gained was about 15 sec.

Investigating potential wet bias in the Purple Crow Lidar water vapor measurements

NASA Astrophysics Data System (ADS)

VanKerkhove, Jeffrey; Sica, R. J.; Wing, R.; Argall, P. S.

2018-04-01

The Purple Crow Lidar is a large aperture lidar, capable of retrieving water vapor into the strato-sphere. A comparison with the ALVICE lidar in 2012 showed water vapor measurements were consistently larger than those of ALVICE in the lower stratosphere, prompting an investigation of the system. Processing approaches and additional instrumental corrections are considered.

Large Aperture Scanning Lidar Based on Holographic Optical Elements

NASA Technical Reports Server (NTRS)

Schwemmer, Geary K.; Miller, David O.; Wilkerson, Thomas D.; Andrus, Ionio; Guerra, David V.; Einaudi, Franco (Technical Monitor)

2001-01-01

Lidar remote sensing instruments can make a significant contribution to satisfying many of the required measurements of atmospheric and surface parameters for future spaceborne platforms, including topographic altimeters, atmospheric profiles of, wind, humidity, temperature, trace molecules, aerosols, and clouds. It is highly desirable to have wide measurement swaths for rapid coverage rather than just the narrow ribbon of data that is obtained with a nadir only observation. For most applications global coverage is required, and for wind measurements scanning or pointing is required in order to retrieve the full 3-D wind vector from multiple line-of-sight Doppler measurements. Conventional lidar receivers make up a substantial portion of the instrument's size and weight. Wide angle scanning typically requires a large scanning mirror in front of the receiver telescope, or pointing the entire telescope and aft optics assembly, Either of these methods entails the use of large bearings, motors, gearing and their associated electronics. Spaceborne instruments also need reaction wheels to counter the torque applied to the spacecraft by these motions. NASA has developed simplified conical scanning telescopes using Holographic Optical Elements (HOEs) to reduce the size, mass, angular momentum, and cost of scanning lidar systems. NASA has developed two operating lidar systems based on 40 cm diameter HOEs. The first such system, named Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing (PHASERS) was a joint development between NASA Goddard Space Flight Center (GSFC) and the University of Maryland College Park. PHASERS is based on a reflection HOE for use at the doubled Nd:YAG laser wavelength of 532 nm and has recently undergone a number of design changes in a collaborative effort between GSFC and Saint Anselm College in New Hampshire. The next step was to develop IR transmission HOEs for use with the Nd:YAG fundamental in the Holographic Airborne Rotating Lidar Instrument Experiment (HARLIE). The HOE spins like a compact disk in a large ring ball bearing. In an aircraft the HOE faces down, looking out through a window at an angle of 45 degrees off-nadir. The HOE diffracts 85% of the incident 532 nm light into a 160 micron spot at a focal length of 1 meter. HARLIE is a field deployable lidar measuring aerosol, cloud, and boundary layer backscatter for atmospheric research. It has flown several times and is also used from a ground-based trailer in an upward-looking mode. The HOE generates a 45 degree conical scan pattern by rotating at speeds up to 30 rpm. Like PHASERS, the HOE in HARLIE serves both as the laser collimating lens as well as the receiver telescope primary optic. The telescope is coupled to the receiver package via fiber optic. The transmitter is a diode pumped Nd:YAG laser operating at 1064 nm, delivering 1 mJ pulses at a 5 KHz rep-rate. The receiver has a 200 microradian field-of-view and a 0.5 nm optical bandpass. The photon counting data system utilizes a single Geiger-mode silicon avalanche photodiode detector, This new technology has also presented us with new data visualization challenges as well as new measurement techniques. The backscatter data obtained from a stationary (i.e. ground-based) scanning HOE lidar is on the surface of a cone, which when viewed over many consecutive scans can reveal atmospheric motions on this surface over time as the atmosphere advects over the site. In a moving platform such as an airplane or satellite, the data from consecutive scans cover different areas under the flight path, revealing atmospheric structure in 3-dimensions. An example of a visualization of HARLIE ground-based data is presented, showing aerosol backscatter on a 90 degree conical surface generated from one 360 degree scan of the lidar during the HOLO-1 field campaign on the afternoon of 10 March 1999. Higher backscatter levels are rendered as lighter signal against a dark background. Breaking Kelvin-Helmholtz waves are evident on the north side of the scan at an altitude of 10-11 km. Time series of successive scans made at regular intervals render unique views of atmospheric motions, from which vertical profiles of atmospheric wind vectors can be obtained using a unique data analysis approach. Wind vectors obtained from the lidar were compared with co-located radiosonde wind profiles during an intensive operating period in September-October 2000 at the Atmospheric Radiation Measurement Program's Southern Great Plains Central Facility.

Narrow-field-of-view bathymetrical lidar: theory and field test

NASA Astrophysics Data System (ADS)

Feygels, Viktor I.; Wright, C. Wayne; Kopilevich, Yuri I.; Surkov, Alexey I.

2003-11-01

The purpose of this paper is to derive a reliable theory to predict the performance of a narrow-FOV bathymetric lidar. A fundamental discrepancy between the theoretical estimate and experimental results was the inspiration for the work presented here Meeting oceanographic mapping requirements is a critically important goal for littoral laser bathymetry. In contrast to traditional airborne lidar system which are optimized for recovering signals from the deepest possible waters , the above challenge may be met with a radical narrowing to the lidar transmit beam and receiver field of view (FOV) employed in EAARL (Experimental Advanced Airborne Research Lidar, NASA). In this paper we discuss theoretical analysis carried out on the basis of a sophisticated "multiple-forward scattering and single-backscattering model" for lidar return signals allows a quantitative estimation of the advantages of a narrow-FOV system over traditional bathymetric lidars (SHOALS-400, SHOALS-100, LADS Mk II) when used in clear shallow-water cases. Some of those advantages are: ¸ Increase in bottom definition (or reduced false-alarm probability) due to the enhanced contrast of the bottom return over the background backscatter from the water column, ¸ Enhancement in depth measurement accuracy resulting from narrower bottom return pulse width, ¸ Reduction of post-surface return effects in the lidar photo-multiplier detector due to a more rapid decay of water column backscatter, ¸ Greatly improved rejection of ambient light permitting lidar operations in all zenith sun angles and flight directions. The model computations make it possible to estimate the maximal operational depth for the system under consideration by the implementation of statistical theory of detectability. These computations depend on the prevailing seawater optical properties and lidar parameters. The theoretical predictions are compared with results obtained in the field test of the EAARL system carried out in Florida Keys in 2001.

Construction and first atmospheric observations of a high spectral resolution lidar system in Argentina in the frame of a trinational Japanese-Argentinean-Chilean collaboration

NASA Astrophysics Data System (ADS)

Papandrea, S.; Jin, Y.; Ristori, P.; Otero, L.; Nishizawa, T.; Mizuno, A.; Sugimoto, N.; Quel, E.

2016-05-01

Atmospheric monitoring stations are being developed in Argentina. The most important targets are volcanic ashes, desert aerosols in particular Patagonian dust and biomass burning aerosols. Six stations deployed in the Patagonian Region and Buenos Aires have lidar systems, sun photometers integrated to the AERONET/NASA monitoring network, in situ optical particle analyzers, four solar radiation sensors (pyranometer, UVA, UVB and GUV), and meteorological equipment. The stations are in the main international airports of the Regions (San Carlos de Bariloche, Comodoro Rivadavia, Neuquén, Rio Gallegos) and in Buenos Aires (Aeroparque Jorge Newbery and at CEILAP/CITEDEF). CEILAP and the National Institute of Environmental Studies (NIES) at Tsukuba, Japan developed the first iodine cell-based high spectral resolution lidar (HSRL) in Argentina to add in the lidar network. We upgraded the standard CEILAP multi-wavelength Raman lidar adding the laser frequency tuning system and the 532 iodine-filtered channel at the reception to built the HSRL. HSRL will provide daytime and nighttime direct observation of the aerosol and cloud optical properties (backscatter and extinction) without the pre-assumption of the lidar ratio. This work shows the design and construction of the first Argentinean HSRL. We also show the first lidar observations done in the country with this kind of lidar.

Finite element modal analysis of a vehicle-borne lidar cabin

NASA Astrophysics Data System (ADS)

Chen, Yafeng; Liu, Qiuwu; Wang, Jie; Hu, Shunxing; Huang, Jian

2018-02-01

Using SolidWorks software, the finite element modal analysis of a vehicle-borne pollution monitoring lidar cabin is carried out. The lidar cabin for the integrated lidar can ensure that the lidar system has good maneuverability and can effectively monitor the emission of air pollution. Since lidar is an integrated system of optics, mechanism, electricity and calculation, the performance of the cabin is directly related to the safety of the equipment and the lidar to work properly. Firstly, the cubic structure is modeled to simulate the cubic structure. Then, the model of the cabin model is analyzed by using the simulation plug-in, and the first 10 modes and natural frequencies are analyzed and recorded. The calculation results show that the cabin is dominated by bending vibration, and the amplitude area is concentrated in the opening of some windows and doors on each board. Therefore, we should increase the number of reinforcement bars or the strength of the skeleton in the vicinity of the door and window. At the same time, to avoid the resonance and ensure the precision of the optical elements and the electrical components and avoid structural damage of the cabin, the incentive frequency should be keep away from the natural frequency of the cabin. The vehicle-borne lidar system has been put into operation, and the analysis results have direct meaning to the transport of the cabin and the normal work.

Modeling of a tilted pressure-tuned field-widened Michelson interferometer for application in high spectral resolution lidar

NASA Astrophysics Data System (ADS)

Liu, Dong; Hostetler, Chris; Miller, Ian; Cook, Anthony; Hair, Jonathan

2011-10-01

High spectral resolution lidars (HSRLs) designed for aerosol and cloud remote sensing are increasingly being deployed on aircraft and called for on future space-based missions. The HSRL technique relies on spectral discrimination of the atmospheric backscatter signals to enable independent, unambiguous retrieval of aerosol extinction and backscatter. A compact, monolithic field-widened Michelson interferometer is being developed as the spectral discrimination filter for an HSRL system at NASA Langley Research Center. The Michelson interferometer consists of a cubic beam splitter, a solid glass arm, and an air arm. The spacer that connects the air arm mirror to the main part of the interferometer is designed to optimize thermal compensation such that the frequency of maximum interference can be tuned with great precision to the transmitted laser wavelength. In this paper, a comprehensive radiometric model for the field-widened Michelson interferometeric spectral filter is presented. The model incorporates the angular distribution and finite cross sectional area of the light source, reflectance of all surfaces, loss of absorption, and lack of parallelism between the airarm and solid arm, etc. The model can be used to assess the performance of the interferometer and thus it is a useful tool to evaluate performance budgets and to set optical specifications for new designs of the same basic interferometer type.

Accuracy evaluation of 3D lidar data from small UAV

NASA Astrophysics Data System (ADS)

Tulldahl, H. M.; Bissmarck, Fredrik; Larsson, Hâkan; Grönwall, Christina; Tolt, Gustav

2015-10-01

A UAV (Unmanned Aerial Vehicle) with an integrated lidar can be an efficient system for collection of high-resolution and accurate three-dimensional (3D) data. In this paper we evaluate the accuracy of a system consisting of a lidar sensor on a small UAV. High geometric accuracy in the produced point cloud is a fundamental qualification for detection and recognition of objects in a single-flight dataset as well as for change detection using two or several data collections over the same scene. Our work presented here has two purposes: first to relate the point cloud accuracy to data processing parameters and second, to examine the influence on accuracy from the UAV platform parameters. In our work, the accuracy is numerically quantified as local surface smoothness on planar surfaces, and as distance and relative height accuracy using data from a terrestrial laser scanner as reference. The UAV lidar system used is the Velodyne HDL-32E lidar on a multirotor UAV with a total weight of 7 kg. For processing of data into a geographically referenced point cloud, positioning and orientation of the lidar sensor is based on inertial navigation system (INS) data combined with lidar data. The combination of INS and lidar data is achieved in a dynamic calibration process that minimizes the navigation errors in six degrees of freedom, namely the errors of the absolute position (x, y, z) and the orientation (pitch, roll, yaw) measured by GPS/INS. Our results show that low-cost and light-weight MEMS based (microelectromechanical systems) INS equipment with a dynamic calibration process can obtain significantly improved accuracy compared to processing based solely on INS data.

High Density LiDAR and Orthophotography in UXO Wide Area Assessment

DTIC Science & Technology

2008-01-01

4 Figure 2. Helicopter-Mounted LiDAR and Orthophoto Sensor Equipment...4 Figure 3. LiDAR and Orthophoto System Installed on Helicopter........................................ 6 Figure 4. Kirtland Precision...17 Figure 11. Orthophoto Data Density Results

Experimental investigation into infrasonic emissions from atmospheric turbulence.

PubMed

Shams, Qamar A; Zuckerwar, Allan J; Burkett, Cecil G; Weistroffer, George R; Hugo, Derek R

2013-03-01

Clear air turbulence (CAT) is the leading cause of in-flight injuries and in severe cases can result in fatalities. The purpose of this work is to design and develop an infrasonic array network for early warning of clear air turbulence. The infrasonic system consists of an infrasonic three-microphone array, compact windscreens, and data management system. Past experimental efforts to detect acoustic emissions from CAT have been limited. An array of three infrasonic microphones, operating in the field at NASA Langley Research Center, on several occasions received signals interpreted as infrasonic emissions from CAT. Following comparison with current lidar and other past methods, the principle of operation, the experimental methods, and experimental data are presented for case studies and confirmed by pilot reports. The power spectral density of the received signals was found to fit a power law having an exponent of -6 to -7, which is found to be characteristics of infrasonic emissions from CAT, in contrast to findings of the past.

Web-based data acquisition and management system for GOSAT validation Lidar data analysis

NASA Astrophysics Data System (ADS)

Okumura, Hiroshi; Takubo, Shoichiro; Kawasaki, Takeru; Abdullah, Indra N.; Uchino, Osamu; Morino, Isamu; Yokota, Tatsuya; Nagai, Tomohiro; Sakai, Tetsu; Maki, Takashi; Arai, Kohei

2012-11-01

An web-base data acquisition and management system for GOSAT (Greenhouse gases Observation SATellite) validation lidar data analysis is developed. The system consists of data acquisition sub-system (DAS) and data management sub-system (DMS). DAS written in Perl language acquires AMeDAS ground-level meteorological data, Rawinsonde upper-air meteorological data, ground-level oxidant data, skyradiometer data, skyview camera images, meteorological satellite IR image data and GOSAT validation lidar data. DMS written in PHP language demonstrates satellite-pass date and all acquired data.

Airborne Wind Profiling Algorithms for the Pulsed 2-Micron Coherent Doppler Lidar at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Beyon, Jeffrey Y.; Koch, Grady J.; Kavaya, Michael J.; Ray, Taylor J.

2013-01-01

Two versions of airborne wind profiling algorithms for the pulsed 2-micron coherent Doppler lidar system at NASA Langley Research Center in Virginia are presented. Each algorithm utilizes different number of line-of-sight (LOS) lidar returns while compensating the adverse effects of different coordinate systems between the aircraft and the Earth. One of the two algorithms APOLO (Airborne Wind Profiling Algorithm for Doppler Wind Lidar) estimates wind products using two LOSs. The other algorithm utilizes five LOSs. The airborne lidar data were acquired during the NASA's Genesis and Rapid Intensification Processes (GRIP) campaign in 2010. The wind profile products from the two algorithms are compared with the dropsonde data to validate their results.

Line-Based Registration of Panoramic Images and LiDAR Point Clouds for Mobile Mapping.

PubMed

Cui, Tingting; Ji, Shunping; Shan, Jie; Gong, Jianya; Liu, Kejian

2016-12-31

For multi-sensor integrated systems, such as the mobile mapping system (MMS), data fusion at sensor-level, i.e., the 2D-3D registration between an optical camera and LiDAR, is a prerequisite for higher level fusion and further applications. This paper proposes a line-based registration method for panoramic images and a LiDAR point cloud collected by a MMS. We first introduce the system configuration and specification, including the coordinate systems of the MMS, the 3D LiDAR scanners, and the two panoramic camera models. We then establish the line-based transformation model for the panoramic camera. Finally, the proposed registration method is evaluated for two types of camera models by visual inspection and quantitative comparison. The results demonstrate that the line-based registration method can significantly improve the alignment of the panoramic image and the LiDAR datasets under either the ideal spherical or the rigorous panoramic camera model, with the latter being more reliable.

Line-Based Registration of Panoramic Images and LiDAR Point Clouds for Mobile Mapping

PubMed Central

Cui, Tingting; Ji, Shunping; Shan, Jie; Gong, Jianya; Liu, Kejian

2016-01-01

For multi-sensor integrated systems, such as the mobile mapping system (MMS), data fusion at sensor-level, i.e., the 2D-3D registration between an optical camera and LiDAR, is a prerequisite for higher level fusion and further applications. This paper proposes a line-based registration method for panoramic images and a LiDAR point cloud collected by a MMS. We first introduce the system configuration and specification, including the coordinate systems of the MMS, the 3D LiDAR scanners, and the two panoramic camera models. We then establish the line-based transformation model for the panoramic camera. Finally, the proposed registration method is evaluated for two types of camera models by visual inspection and quantitative comparison. The results demonstrate that the line-based registration method can significantly improve the alignment of the panoramic image and the LiDAR datasets under either the ideal spherical or the rigorous panoramic camera model, with the latter being more reliable. PMID:28042855

Laboratory studies of in vivo fluorescence of phytoplankton

NASA Technical Reports Server (NTRS)

Brown, C. A., Jr.; Farmer, F. H.; Jarrett, O., Jr.; Staton, W. L.

1978-01-01

A lidar system is developed that uses four selected excitation wavelengths to induce chlorophyll 'a' fluorescence which is indicative of both the concentration and diversity of phytoplankton. The operating principles of the system and the results of measurements of phytoplankton fluorescence in a controlled laboratory environment are presented. A comparative study of results from lidar fluorosensor laboratory tank tests using representative species of phytoplankton in single and multispecies cultures from each of four color groups reveals that (1) there is good correlation between the fluorescence of chlorophyll 'a' remotely simulated and detected by the lidar system and in-situ measurements using four similar excitation wavelengths in a flow-through fluorometer; (2) good correlation exists between the total chlorophyll 'a' calculated from lidar-fluorosensor data and measurements obtained by the Strickland-Parsons method; and (3) the lidar fluorosensor can provide an index of population diversity.

NASA Lidar system support and MOPA technology demonstration

NASA Technical Reports Server (NTRS)

Laughman, L. M.; Capuano, B.; Wayne, R. J.

1986-01-01

A series of lidar design and technology demonstration tasks in support of a CO2 lidar program is discussed. The first of these tasks is discussed in Section VI of this report under the heading of NASA Optical Lidar Design and it consists of detailed recommendations for the layout of a CO2 Doppler lidar incorporating then existing NASA optical components and mounts. The second phase of this work consisted of the design, development, and delivery to NASA of a novel acousto-optic laser frequency stabilization system for use with the existing NASA ring laser transmitter. The second major task in this program encompasses the design and experimental demonstration of a master oscillator-power amplifier (MOPA) laser transmitter utilizing a commercially available laser as the amplifier. The MOPA design including the low chirp master oscillator is discussed in detail. Experimental results are given for one, two and three pass amplification. The report includes operating procedures for the MOPA system.

Improving Measurement of Forest Structural Parameters by Co-Registering of High Resolution Aerial Imagery and Low Density LiDAR Data

PubMed Central

Huang, Huabing; Gong, Peng; Cheng, Xiao; Clinton, Nick; Li, Zengyuan

2009-01-01

Forest structural parameters, such as tree height and crown width, are indispensable for evaluating forest biomass or forest volume. LiDAR is a revolutionary technology for measurement of forest structural parameters, however, the accuracy of crown width extraction is not satisfactory when using a low density LiDAR, especially in high canopy cover forest. We used high resolution aerial imagery with a low density LiDAR system to overcome this shortcoming. A morphological filtering was used to generate a DEM (Digital Elevation Model) and a CHM (Canopy Height Model) from LiDAR data. The LiDAR camera image is matched to the aerial image with an automated keypoints search algorithm. As a result, a high registration accuracy of 0.5 pixels was obtained. A local maximum filter, watershed segmentation, and object-oriented image segmentation are used to obtain tree height and crown width. Results indicate that the camera data collected by the integrated LiDAR system plays an important role in registration with aerial imagery. The synthesis with aerial imagery increases the accuracy of forest structural parameter extraction when compared to only using the low density LiDAR data. PMID:22573971

Intercomparison of aerosol measurements performed with multi-wavelength Raman lidars, automatic lidars and ceilometers in the framework of INTERACT-II campaign

NASA Astrophysics Data System (ADS)

Madonna, Fabio; Rosoldi, Marco; Lolli, Simone; Amato, Francesco; Vande Hey, Joshua; Dhillon, Ranvir; Zheng, Yunhui; Brettle, Mike; Pappalardo, Gelsomina

2018-04-01

Following the previous efforts of INTERACT (INTERcomparison of Aerosol and Cloud Tracking), the INTERACT-II campaign used multi-wavelength Raman lidar measurements to assess the performance of an automatic compact micro-pulse lidar (MiniMPL) and two ceilometers (CL51 and CS135) in providing reliable information about optical and geometric atmospheric aerosol properties. The campaign took place at the CNR-IMAA Atmospheric Observatory (760 m a. s. l. ; 40.60° N, 15.72° E) in the framework of ACTRIS-2 (Aerosol Clouds Trace gases Research InfraStructure) H2020 project. Co-located simultaneous measurements involving a MiniMPL, two ceilometers and two EARLINET multi-wavelength Raman lidars were performed from July to December 2016. The intercomparison highlighted that the MiniMPL range-corrected signals (RCSs) show, on average, a fractional difference with respect to those of CNR-IMAA Atmospheric Observatory (CIAO) lidars ranging from 5 to 15 % below 2.0 km a.s.l. (above sea level), largely due to the use of an inaccurate overlap correction, and smaller than 5 % in the free troposphere. For the CL51, the attenuated backscatter values have an average fractional difference with respect to CIAO lidars < 20-30 % below 3 km and larger above. The variability of the CL51 calibration constant is within ±46 %. For the CS135, the performance is similar to the CL51 below 2.0 km a. s. l. , while in the region above 3 km a. s. l. the differences are about ±40 %. The variability of the CS135 normalization constant is within ±47 %.Finally, additional tests performed during the campaign using the CHM15k ceilometer operated at CIAO showed the clear need to investigate the CHM15k historical dataset (2010-2016) to evaluate potential effects of ceilometer laser fluctuations on calibration stability. The number of laser pulses shows an average variability of 10 % with respect to the nominal power which conforms to the ceilometer specifications. Nevertheless, laser pulses variability follows seasonal behavior with an increase in the number of laser pulses in summer and a decrease in winter. This contributes to explain the dependency of the ceilometer calibration constant on the environmental temperature hypothesized during INTERACT.

Coherent lidar airborne wind sensor II: flight-test results at 2 and 10 νm.

PubMed

Targ, R; Steakley, B C; Hawley, J G; Ames, L L; Forney, P; Swanson, D; Stone, R; Otto, R G; Zarifis, V; Brockman, P; Calloway, R S; Klein, S H; Robinson, P A

1996-12-20

The use of airborne laser radar (lidar) to measure wind velocities and to detect turbulence in front of an aircraft in real time can significantly increase fuel efficiency, flight safety, and terminal area capacity. We describe the flight-test results for two coherent lidar airborne shear sensor (CLASS) systems and discuss their agreement with our theoretical simulations. The 10.6-μm CO(2) system (CLASS-10) is a flying brassboard; the 2.02-μm Tm:YAG solid-state system (CLASS-2) is configured in a rugged, light-weight, high-performance package. Both lidars have shown a wind measurement accuracy of better than 1 m/s.

Global Monitoring of Clouds and Aerosols Using a Network of Micro-Pulse Lidar Systems

NASA Technical Reports Server (NTRS)

Welton, Ellsworth J.; Campbell, James R.; Spinhirne, James D.; Scott, V. Stanley

2000-01-01

Long-term global radiation programs, such as AERONET and BSRN, have shown success in monitoring column averaged cloud and aerosol optical properties. Little attention has been focused on global measurements of vertically resolved optical properties. Lidar systems are the preferred instrument for such measurements. However, global usage of lidar systems has not been achieved because of limits imposed by older systems that were large, expensive, and logistically difficult to use in the field. Small, eye-safe, and autonomous lidar systems are now currently available and overcome problems associated with older systems. The first such lidar to be developed is the Micro-pulse lidar System (MPL). The MPL has proven to be useful in the field because it can be automated, runs continuously (day and night), is eye-safe, can easily be transported and set up, and has a small field-of-view which removes multiple scattering concerns. We have developed successful protocols to operate and calibrate MPL systems. We have also developed a data analysis algorithm that produces data products such as cloud and aerosol layer heights, optical depths, extinction profiles, and the extinction-backscatter ratio. The algorithm minimizes the use of a priori assumptions and also produces error bars for all data products. Here we present an overview of our MPL protocols and data analysis techniques. We also discuss the ongoing construction of a global MPL network in conjunction with the AERONET program. Finally, we present some early results from the MPL network.

Multi-static Serial LiDAR for Surveillance and Identification of Marine Life at MHK Installations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alsenas, Gabriel; Dalgleish, Fraser; Ouyang, Bing

Final Report for project DE-EE0006787: Multi-static Serial LiDAR for Surveillance and Identification of Marine Life at MHK Installations. This project developed and tested an optical monitoring system prototype that will be suitable for marine and hydrokinetic (MHK) full project lifecycle observation (baseline, commissioning, and decommissioning), with automated real-time classification of marine animals. This system can be deployed to collect pre-installation baseline species observations at a proposed deployment site with minimal post-processing overhead. To satisfy deployed MHK project species of concern (e.g. Endangered Species Act-listed) monitoring requirements, the system provides automated tracking and notification of the presence of managed animals withinmore » established perimeters of MHK equipment and provides high resolution imagery of their behavior through a wide range of conditions. During a project’s decommissioning stage, the system can remain installed to provide resource managers with post-installation data. Our technology, known as an Unobtrusive Multi-static Serial LiDAR Imager (UMSLI), is a technology transfer of underwater distributed LiDAR imaging technology that preserves the advantages of traditional optical and acoustic solutions while overcoming associated disadvantages for MHK environmental monitoring applications. This new approach is a purposefully-designed, reconfigurable adaptation of an existing technology that can be easily mounted on or around different classes of MHK equipment. The system uses low average power red (638nm) laser illumination to be invisible and eye-safe to marine animals and is compact and cost effective. The equipment is designed for long term, maintenance-free operations, to inherently generate a sparse primary dataset that only includes detected anomalies (animal presence information), and to allow robust real-time automated animal classification/identification with a low data bandwidth requirement. Advantages of the technology over others currently being used or being considered for MHK monitoring include: Unlike a conventional camera, the depth of field is near-infinite and limited by attenuation (approximately 5-8 m) rather than focal properties of a lens; Operation in an adaptive mode which can project a sparse grid of pulses with higher peak power for longer range detection (>10 meters) and track animals within a zone of interest with high resolution imagery for identification of marine life at closer range (<5m); System detection limit and Signal-to-Noise-Ratio is superior to a camera, due to rejection of both backscattering component and ambient solar background; Multiple wide-angle pulsed laser illuminators and bucket detectors can be flexibly configured to cover a 4pi steradian (i.e. omnidirectional) scene volume, while also retrieving 3D features of animal targets from timing information; Process and classification framework centered around a novel active learning and incremental classification classifier that enables accurate identification of a variety of marine animals automatically; A two-tiered monitoring architecture and invisible watermarking-based data archiving and retrieving approach ensures significant data reduction while preserving high fidelity monitoring. A methodology to train and optimize the classifier for target species of concern to optimize site monitoring effectiveness. This technological innovation addresses a high priority regulatory requirement to observe marine life interaction near MHK projects. Our solution improves resource manager confidence that any interactions between marine animals and equipment are observed in a cost-effective and automated manner. Without EERE funding, this novel application of multi-static LiDAR would not have been available to the MHK community for environmental monitoring.« less

Innovative vehicle classification strategies : using LIDAR to do more for less.

DOT National Transportation Integrated Search

2012-06-23

This study examines LIDAR (light detection and ranging) based vehicle classification and classification : performance monitoring. First, we develop a portable LIDAR based vehicle classification system that can : be rapidly deployed, and then we use t...

EAARL-B submerged topography: Barnegat Bay, New Jersey, post-Hurricane Sandy, 2012-2013

USGS Publications Warehouse

Wright, C. Wayne; Troche, Rodolfo J.; Kranenburg, Christine J.; Klipp, Emily S.; Fredericks, Xan; Nagle, David B.

2014-01-01

These remotely sensed, geographically referenced elevation measurements of lidar-derived submerged topography datasets were produced by the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida. This project provides highly detailed and accurate datasets for part of Barnegat Bay, New Jersey, acquired post-Hurricane Sandy on November 1, 5, 16, 20, and 30, 2012; December 5, 6, and 21, 2012; and January 10, 2013. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar system, known as the second-generation Experimental Advanced Airborne Research Lidar (EAARL-B), was used during data acquisition. The EAARL-B system is a raster-scanning, waveform-resolving, green-wavelength (532-nm) lidar designed to map nearshore bathymetry, topography, and vegetation structure simultaneously. The EAARL-B sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, down-looking red-green-blue (RGB) and infrared (IR) digital cameras, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL-B platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL-B system. The resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed originally in a NASA-USGS collaboration. The exploration and processing of lidar data in an interactive or batch mode is supported using ALPS. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. The Airborne Lidar Processing System (ALPS) is used routinely to create maps that represent submerged or sub-aerial topography. Specialized filtering algorithms have been implemented to determine the "bare earth" under vegetation from a point cloud of last return elevations. For more information about similar projects, please visit the Lidar for Science and Resource Management Web site.

Development of a pulsed 9.5 micron lidar for regional scale O3 measurement

NASA Technical Reports Server (NTRS)

Stewart, R. W.

1980-01-01

A pulsed infrared lidar system designed for application to the remote sensing of atmospheric trace gases from an airborne platform is described. The system is also capable of measuring the infrared backscatter characteristics of the ocean surface, terrain, cloud, and aerosol targets. The lidar employed is based on dual wavelength pulse energy measurements in the 9-11 micrometer wavelength region.

A sample design for globally consistent biomass estimation using lidar data from the Geoscience Laser Altimeter System (GLAS)

Treesearch

Sean P. Healey; Paul L. Patterson; Sassan S. Saatchi; Michael A. Lefsky; Andrew J. Lister; Elizabeth A. Freeman

2012-01-01

Lidar height data collected by the Geosciences Laser Altimeter System (GLAS) from 2002 to 2008 has the potential to form the basis of a globally consistent sample-based inventory of forest biomass. GLAS lidar return data were collected globally in spatially discrete full waveform "shots," which have been shown to be strongly correlated with aboveground forest...

Three-dimensional canopy fuel loading predicted using upward and downward sensing LiDAR systems

Treesearch

Nicholas S. Skowronski; Kenneth L. Clark; Matthew Duveneck; John. Hom

2011-01-01

We calibrated upward sensing profiling and downward sensing scanning LiDAR systems to estimates of canopy fuel loading developed from field plots and allometric equations, and then used the LiDAR datasets to predict canopy bulk density (CBD) and crown fuel weight (CFW) in wildfire prone stands in the New Jersey Pinelands. LiDAR-derived height profiles were also...

Wavelength dependence of coherent and incoherent satellite-based lidar measurements of wind velocity and aerosol backscatter

NASA Technical Reports Server (NTRS)

Kavaya, M. J.; Huffaker, R. M.

1986-01-01

The results are presented of a capability study of Earth orbiting lidar systems, at various wavelengths from 1.06 to 10.6 microns, for the measurement of wind velocity and aerosol backscatter, and for the detection of clouds. Both coherent and incoherent lidar systems were modeled and compared for the aerosol backscatter and cloud detection applications.

Addressing Future Technology Challenges Through Innovation and Investment

DTIC Science & Technology

2012-03-01

27   Figure  5:   High   Altitude  LIDAR  Operations  Equipment...deployment of the High Altitude LIDAR Operations Experiment (HALOE) system to Operation Enduring Freedom (OEF). DARPA took a prototype sensor and put...High_Energy_Liquid_Laser_Area_Defense_System_(HELLADS).as px.   7 DARPA, “ High Altitude LIDAR Operations Experiment (HALOE) Information Briefing”, September 2011.   8 Taylor, John

The Tropospheric Wind Lidar Technology Experiment (TWiLiTE): An Airborne Direct Detection Doppler Lidar Instrument Development Program

NASA Technical Reports Server (NTRS)

Gentry, Bruce; McGill, Matthew; Schwemmer, Geary; Hardesty, Michael; Brewer, Alan; Wilkerson, Thomas; Atlas, Robert; Sirota, Marcos; Lindemann, Scott

2006-01-01

Global measurement of tropospheric winds is a key measurement for understanding atmospheric dynamics and improving numerical weather prediction. Global wind profiles remain a high priority for the operational weather community and also for a variety of research applications including studies of the global hydrologic cycle and transport studies of aerosols and trace species. In addition to space based winds, a high altitude airborne system flown on UAV or other advanced platforms would be of great interest for studying mesoscale dynamics and hurricanes. The Tropospheric Wind Lidar Technology Experiment (TWiLiTE) project was selected in 2005 by the NASA Earth Sun Technology Office as part of the Instrument Incubator Program. TWiLiTE will leverage significant research and development investments in key technologies made in the past several years. The primary focus will be on integrating these sub-systems into a complete molecular direct detection Doppler wind lidar system designed for autonomous operation on a high altitude aircraft, such as the NASA WB57, so that the nadir viewing lidar will be able to profile winds through the full troposphere. TWiLiTE is a collaboration involving scientists and technologists from NASA Goddard, NOAA ESRL, Utah State University Space Dynamics Lab and industry partners Michigan Aerospace Corporation and Sigma Space Corporation. NASA Goddard and it's partners have been at the forefront in the development of key lidar technologies (lasers, telescopes, scanning systems, detectors and receivers) required to enable spaceborne global wind lidar measurement. The TWiLiTE integrated airborne Doppler lidar instrument will be the first demonstration of a airborne scanning direct detection Doppler lidar and will serve as a critical milestone on the path to a fixture spaceborne tropospheric wind system. The completed system will have the capability to profile winds in clear air from the aircraft altitude of 18 h to the surface with 250 m vertical resolution and less than 2 meters per second velocity accuracy. The instrument design, technologies and predicted performance will be presented.

First Results of the Land Atmosphere Feedback Experiment

NASA Astrophysics Data System (ADS)

Wulfmeyer, V.; Turner, D. D.

2017-12-01

The Land-Atmosphere Feedback Experiment (LAFE) deployed several state-of-the-art scanning lidar and remote sensing systems to the ARM SGP site during August 2017. A novel synergy of remote sensing systems was applied for simultaneous measurements of land-surface fluxes and horizontal and vertical transport processes in the atmospheric boundary layer (ABL). The impact of spatial inhomogeneities of the soil-vegetation continuum on LA feedback was studied using the scanning capability of the instrumentation as well as soil, vegetation, and surface flux measurements. The synergy of remote sensing and in-situ instruments consisted of three components: 1) The SGP water-vapor and temperature Raman lidar, the SGP Doppler lidar, the University of Hohenheim (UHOH) Doppler lidar, and the NCAR water-vapor DIAL to measure mean profiles and gradients of moisture, temperature, and horizontal wind. Due to their high vertical and temporal resolutions, also profiles of higher-order turbulent moments in the water vapor and wind fields as well as of profiles of the latent heat flux, the sensible heat flux, TKE, and momentum flux were observed. 2) A novel scanning lidar system synergy consisting of the NOAA High-Resolution Doppler lidar, the UHOH water-vapor differential absorption lidar, and the UHOH temperature rotational Raman lidar. These systems performed coordinated range-height indicator (RHI) scans from just above the canopy level to the lower troposphere including the interfacial layer at the ABL top. This component was augmented by three energy balance closure towers of NOAA and one EBC station of UHOH. 3) The University of Wisconsin SPARC and the University of Oklahoma CLAMPS systems operating two vertically pointing atmospheric emitted radiance interferometers and two Doppler lidar systems scanning cross track to the central RHI for determining the surface friction velocity and the horizontal variability of temperature, moisture, and wind. NOAA ARL also provided UAS and aircraft measurements (Navajo Piper) in accordance with the surface scans. Thus, both the variability of surface fluxes and CBL dynamics and thermodynamics over the SGP site was studied for the first time. This is essential for advanced observation and understanding of LA feedback. First results are presented at the conference.

Prediction of topographic and bathymetric measurement performance of airborne low-SNR lidar systems

NASA Astrophysics Data System (ADS)

Cossio, Tristan

Low signal-to-noise ratio (LSNR) lidar (light detection and ranging) is an alternative paradigm to traditional lidar based on the detection of return signals at the single photoelectron level. The objective of this work was to predict low altitude (600 m) LSNR lidar system performance with regards to elevation measurement and target detection capability in topographic (dry land) and bathymetric (shallow water) scenarios. A modular numerical sensor model has been developed to provide data for further analysis due to the dearth of operational low altitude LSNR lidar systems. This simulator tool is described in detail, with consideration given to atmospheric effects, surface conditions, and the effects of laser phenomenology. Measurement performance analysis of the simulated topographic data showed results comparable to commercially available lidar systems, with a standard deviation of less than 12 cm for calculated elevation values. Bathymetric results, although dependent largely on water turbidity, were indicative of meter-scale horizontal data spacing for sea depths less than 5 m. The high prevalence of noise in LSNR lidar data introduces significant difficulties in data analysis. Novel algorithms to reduce noise are described, with particular focus on their integration into an end-to-end target detection classifier for both dry and submerged targets (cube blocks, 0.5 m to 1.0 m on a side). The key characteristic exploited to discriminate signal and noise is the temporal coherence of signal events versus the random distribution of noise events. Target detection performance over dry earth was observed to be robust, reliably detecting over 90% of targets with a minimal false alarm rate. Comparable results were observed in waters of high clarity, where the investigated system was generally able to detect more than 70% of targets to a depth of 5 m. The results of the study show that CATS, the University of Florida's LSNR lidar prototype, is capable of high fidelity (decimeter-scale) coverage of the topographic zone with limited applicability to shallow waters less than 5 m deep. To increase the spatial-temporal contrast between signal and noise events, laser pulse rate is the optimal system characteristic to improve in future LSNR lidar units.

T-matrix modeling of linear depolarization by morphologically complex soot and soot-containing aerosols

NASA Astrophysics Data System (ADS)

Mishchenko, Michael I.; Liu, Li; Mackowski, Daniel W.

2013-07-01

We use state-of-the-art public-domain Fortran codes based on the T-matrix method to calculate orientation and ensemble averaged scattering matrix elements for a variety of morphologically complex black carbon (BC) and BC-containing aerosol particles, with a special emphasis on the linear depolarization ratio (LDR). We explain theoretically the quasi-Rayleigh LDR peak at side-scattering angles typical of low-density soot fractals and conclude that the measurement of this feature enables one to evaluate the compactness state of BC clusters and trace the evolution of low-density fluffy fractals into densely packed aggregates. We show that small backscattering LDRs measured with ground-based, airborne, and spaceborne lidars for fresh smoke generally agree with the values predicted theoretically for fluffy BC fractals and densely packed near-spheroidal BC aggregates. To reproduce higher lidar LDRs observed for aged smoke, one needs alternative particle models such as shape mixtures of BC spheroids or cylinders.

T-Matrix Modeling of Linear Depolarization by Morphologically Complex Soot and Soot-Containing Aerosols

NASA Technical Reports Server (NTRS)

Mishchenko, Michael I.; Liu, Li; Mackowski, Daniel W.

2013-01-01

We use state-of-the-art public-domain Fortran codes based on the T-matrix method to calculate orientation and ensemble averaged scattering matrix elements for a variety of morphologically complex black carbon (BC) and BC-containing aerosol particles, with a special emphasis on the linear depolarization ratio (LDR). We explain theoretically the quasi-Rayleigh LDR peak at side-scattering angles typical of low-density soot fractals and conclude that the measurement of this feature enables one to evaluate the compactness state of BC clusters and trace the evolution of low-density fluffy fractals into densely packed aggregates. We show that small backscattering LDRs measured with groundbased, airborne, and spaceborne lidars for fresh smoke generally agree with the values predicted theoretically for fluffy BC fractals and densely packed near-spheroidal BC aggregates. To reproduce higher lidar LDRs observed for aged smoke, one needs alternative particle models such as shape mixtures of BC spheroids or cylinders.

Issues to be addressed in the design and fabrication of ultralightweight, meter class optics

NASA Astrophysics Data System (ADS)

Krumweide, Gary C.; Dyer, J.; Kasl, E. P.; Mehle, G. V.

1998-01-01

There is a growing need for large aperture, ultralightweight, deployable optics (mirrors) for various science, military and commercial compact satellites (Pleimann 1997). This paper will examine the engineering and manufacturing considerations that must be addressed in order to satisfy the requirements for these sought after optics. In order to limit the scope of this paper, only Graphite Fiber Reinforced/Polymer Matrix Composites (GFR/PMC) will be under consideration because of the potential to satisfy ultralightweight mirror requirements (5-10 Kg/m2) (Kasl 1997). The requirements associated with specular mirror concepts that Composite Optics, Incorporated (COI) has proposed to Air Force Research Laboratory (AFRL/VS) and NASA Langley Research Center for visible range optics and LIDAR (light bucket) optics, respectively, will also be our interest. Moreover, it is the intent of this paper to illustrate how COI's proposed design/manufacturing concepts for visible and LIDAR optics have evolved based on overcoming, or working around, material constraints and/or undesirable characteristics associated with GFR/PMC.

Gating characteristics of photomultiplier tubes for Lidar applications

NASA Technical Reports Server (NTRS)

Barrick, J. D. W.

1986-01-01

A detector test facility was developed and applied in the evaluation and characterization of lidar detectors in support of the multipurpose airborne differential absorption lidar (DIAL) system based at the Langley Research Center (LaRC). A performance data base of various detector configurations available to the DIAL system was obtained for optimum lidar detector selection. Photomultiplier tubes (PMT's) with multialkaline and bialkaline photocathodes were evaluated in voltage-divider networks (bases) by using either the focusing electrode or dynodes as a gating mechanism. Characteristics used for detector evaluation included gain stability, signal rise time, and the ability to block unwanted high light levels.

Software defined coherent lidar (SD-Cl) architecture

NASA Astrophysics Data System (ADS)

Laghezza, F.; Onori, D.; Scotti, F.; Bogoni, A.

2017-09-01

In recent years, thanks to the innovation in optical and electro-optical components, space based light detection and ranging (Lidar) systems are having great success, as a considerable alternative to passive radiometers or microwave sensors [1]. One of the most important applications, for space based Lidars, is the measure of target's distance and its relative properties as e.g., topography, surface's roughness and reflectivity, gravity and mass, that provide useful information for surface mapping, as well as semi-autonomous landing functionalities on lowgravity bodies (moons and asteroids). These kind of systems are often called Lidar altimeters or laser rangefinders.

Development of a 2-micron Pulsed Direct Detection IPDA Lidar for CO2 Measurement

NASA Astrophysics Data System (ADS)

Yu, J.; Petros, M.; Singh, U. N.

2013-12-01

NASA Langley is developing a 2-micron pulsed Integrated Path Differential Absorption (IPDA) lidar for atmospheric CO2 measurements. The high pulse energy, direct detection lidar operating at CO2 2-micron absorption band provides an alternate approach to measure CO2 concentrations with significant advantages. The objective of this development is to integrate an existing high energy double-pulsed 2-micron laser transmitter with a direct detection receiver and telescope to enable a first proof of principle demonstration of airborne direct detection CO2 measurements at 2-micron wavelength. It is expected to provide high-precision measurement capability by unambiguously eliminating contamination from aerosols and clouds that can bias the IPDA measurement. The system is scheduled to fly on NASA UC12 or B200 research aircrafts before the end of 2013. This paper will describe the design of the airborne 2-micron pulsed IPDA lidar system; the lidar operation parameters; the wavelength pair selection; laser transmitter energy, pulse rate, beam divergence, double pulse generation and accurate frequency control; detector characterization; telescope design; lidar structure design; and lidar signal to noise ratio estimation.

Developing a portable, autonomous aerosol backscatter lidar for network or remote operations

NASA Astrophysics Data System (ADS)

Strawbridge, K. B.

2013-03-01

Lidar has the ability to detect the complex vertical structure of the atmosphere and can therefore identify the existence and extent of aerosols with high spatial and temporal resolution, making it well suited for understanding atmospheric dynamics and transport processes. Environment Canada has developed a portable, autonomous lidar system that can be monitored remotely and operated continuously except during precipitation events. The lidar, housed in a small trailer, simultaneously emits two wavelengths of laser light (1064 nm and 532 nm) at energies of approximately 150 mJ/pulse/wavelength and detects the backscatter signal at 1064 nm and both polarizations at 532 nm. For laser energies of this magnitude, the challenge resides in designing a system that meets the airspace safety requirements for autonomous operations. Through the combination of radar technology, beam divergence, laser cavity interlocks and using computer log files, this risk was mitigated. A Continuum Inlite small footprint laser is the backbone of the system because of three design criteria: requiring infrequent flash lamp changes compared to previous Nd : YAG Q-switch lasers, complete software control capability and a built-in laser energy monitoring system. A computer-controlled interface was designed to monitor the health of the system, adjust operational parameters and maintain a climate-controlled environment. Through an Internet connection, it also transmitted the vital performance indicators and data stream to allow the lidar profile data for multiple instruments from near ground to 15 km, every 10 s, to be viewed, in near real-time via a website. The details of the system design and calibration will be discussed and the success of the instrument as tested within the framework of a national lidar network dubbed CORALNet (Canadian Operational Research Aerosol Lidar Network). In addition, the transport of a forest fire plume across the country will be shown as evidenced by the lidar network, HYSPLIT back trajectories, MODIS imagery and CALIPSO overpasses.

Developing a portable, autonomous aerosol backscatter lidar for network or remote operations

NASA Astrophysics Data System (ADS)

Strawbridge, K. B.

2012-11-01

Lidar has the ability to detect the complex vertical structure of the atmosphere and can therefore identify the existence and extent of aerosols with high spatial and temporal resolution, making it well-suited for understanding atmospheric dynamics and transport processes. Environment Canada has developed a portable, autonomous lidar system that can be monitored remotely and operate continuously except during precipitation events. The lidar, housed in a small trailer, simultaneously emits two wavelengths of laser light (1064 nm and 532 nm) at energies of approximately 150 mJ/pulse/wavelength and detects the backscatter signal at 1064 nm and both polarizations at 532 nm. For laser energies of this magnitude, the challenge resides in designing a system that meets the airspace safety requirements for autonomous operations. Through the combination of radar technology, beam divergence, laser cavity interlocks and using computer log files, this risk was mitigated. A Continuum Inlite small footprint laser is the backbone of the system because of three design criteria: requiring infrequent flash lamp changes compared to previous Nd:YAG Q-switch lasers, complete software control capability and a built-in laser energy monitoring system. A computer-controlled interface was designed to monitor the health of the system, adjust operational parameters and maintain a climate-controlled environment. Through an internet connection, it also transmitted the vital performance indicators and data stream to allow the lidar profile data for multiple instruments from near ground to 15 km, every 10 s, to be viewed, in near real-time via a website. The details of the system design and calibration will be discussed and the success of the instrument as tested within the framework of a national lidar network dubbed CORALNet (Canadian Operational Research Aerosol Lidar Network). In addition, the transport of a forest fire plume across the country will be shown as evidenced by the lidar network, HYSPLIT back trajectories, MODIS imagery and CALIPSO overpasses.

Multipurpose Fiber Injected-micro-spherical LIDAR System

NASA Technical Reports Server (NTRS)

Abdelayem, Hossin; Jamison, Tracee

2005-01-01

A technological revolution is occurring in the field of fiber lasers. Over the past two years, the level of power has increased from approx. 100 watts to nearly 1 kilowatt. We are developing a novel fiber laser system, which is a satellite-based LIDAR transmitter of multi-lines. The system is made of a hollow fiber filled with micro-spheres doped with lasing materials. Each sphere has its inherent optical cavity, which makes the system a cavity free and in the same time, emits multi-laser lines for simultaneous multi-task operations. The system is also rugged, compact, lightweight, and durable. Our earlier studies on micro-spheres doped with different laser dyes demonstrated the emission of extremely fine laser lines of less than 3 A line-width, which are of interest for spectroscopic applications, sensing, imaging, and optical communications. Individual dye-doped micro-spheres demonstrated a lasing resonance peaks phenomenon in their fluorescence spectra of linear and nonlinear features that do not exist in the bulk dye solutions. Each individual micro-sphere acts as a laser system with inherent cavity, where the fluorescence line suffers multiple internal reflections within the micro-sphere and gains enough energy to become a laser line. Such resonance peaks are dependent on the sphere's morphology, size, shape, and its refractive index. These resonance peaks are named structural resonance, whispering modes or whispering gallery modes, creeping waves, circumferential waves, surfaces modes, and virtual modes. All of these names refer to the same phenomenon of morphology dependent resonance (MDR), which has already been described and predicted precisely by electromagnetic theory and Lorentz-Mie theory since 1908. The resonance peaks become more obvious when the particle size approaches and exceeds the wavelength of the laser used and the relative index of the particle is greater than that of the surrounding medium. Additional information is included in the original extended abstract.

Validation of the ICEsat vegetation product using crown-area-weighted mean height derived using crown delineation with discrete return lidar data

Treesearch

Yong Pang; Michael Lefsky; Hans-Erik Andersen; Mary Ellen Miller; Kirk Sherrill

2008-01-01

The Geoscience Laser Altimeter System (GLAS), a spaceborne light detection and ranging (lidar) sensor, has acquired over 250 million lidar observations over forests globally, an unprecedented dataset of vegetation height information. To be useful, GLAS must be calibrated to measurements of height used in forestry inventory and ecology. Airborne discrete return lidar (...

Lidar backscattering measurements of background stratospheric aerosols

NASA Technical Reports Server (NTRS)

Remsberg, E. E.; Northam, G. B.; Butler, C. F.

1979-01-01

A comparative lidar-dustsonde experiment was conducted in San Angelo, Texas, in May 1974 in order to estimate the uncertainties in stratospheric-aerosol backscatter for the NASA Langley 48-inch lidar system. The lidar calibration and data-analysis procedures are discussed. Results from the Texas experiment indicate random and systematic uncertainties of 35 and 63 percent, respectively, in backscatter from a background stratospheric-aerosol layer at 20 km.

Polarization lidar for atmospheric monitoring

NASA Astrophysics Data System (ADS)

Liu, Qiaojun; Wu, Chengxuan; Yuk Sun Cheng, Andrew; Wang, Zhangjun; Meng, Xiangqian; Chen, Chao; Li, Xianxin; Liu, Xingtao; Zhang, Hao; Zong, Fangyi

2018-04-01

Aerosol plays an important role in global climate and weather changes. Polarization lidar captures parallel and perpendicular signals from atmosphere to research aerosols. The lidar system we used has three emission wavelengths and could obtain the atmospheric aerosol extinction coefficient, backscattering coefficient and depolarization ratio. In this paper, the design of the lidar is described. The methods of data acquisition and inversion are given. Some recent results are presented.

New calibration technique for water-vapor Raman lidar combined with the GNSS precipitable water vapor and the Meso-Scale Model

NASA Astrophysics Data System (ADS)

Kakihara, H.; Yabuki, M.; Kitafuji, F.; Tsuda, T.; Tsukamoto, M.; Hasegawa, T.; Hashiguchi, H.; Yamamoto, M.

2017-12-01

Atmospheric water vapor plays an important role in atmospheric chemistry and meteorology, with implications for climate change and severe weather. The Raman lidar technique is useful for observing water-vapor with high spatiotemporal resolutions. However, the calibration factor must be determined before observations. Because the calibration factor is generally evaluated by comparing Raman-signal results with those of independent measurement techniques (e.g., radiosonde), it is difficult to apply this technique to lidar sites where radiosonde observation cannot be carried out. In this study, we propose a new calibration technique for water-vapor Raman lidar using global navigation satellite system (GNSS)-derived precipitable water vapor (PWV) and Japan Meteorological Agency meso-scale model (MSM). The analysis was accomplished by fitting the GNSS-PWV to integrated water-vapor profiles combined with the MSM and the results of the lidar observations. The maximum height of the lidar signal applicable to this method was determined within 2.0 km by considering the signal noise mainly caused by low clouds. The MSM data was employed at higher regions that cannot apply the lidar data. This method can be applied to lidar signals lower than a limited height range due to weather conditions and lidar specifications. For example, Raman lidar using a laser operating in the ultraviolet C (UV-C) region has the advantage of daytime observation since there is no solar background radiation in the system. The observation range is, however, limited at altitudes lower than 1-3 km because of strong ozone absorption at the UV-C region. The new calibration technique will allow the utilization of various types of Raman lidar systems and provide many opportunities for calibration. We demonstrated the potential of this method by using the UV-C Raman lidar and GNSS observation data at the Shigaraki MU radar observatory (34°51'N, 136°06'E; 385m a.s.l.) of the Research Institute for Sustainable Humanosphere (RISH, Kyoto University, Japan, in June 2016. Differences of the calibration factor between the proposed method and the conventional method were 0.7% under optimal conditions such as clear skies and low ozone concentrations.

Pre-Launch End-to-End Testing Plans for the SPAce Readiness Coherent Lidar Experiment (SPARCLE)

NASA Technical Reports Server (NTRS)

Kavaya, Michael J.

1999-01-01

The SPAce Readiness Coherent Lidar Experiment (SPARCLE) mission was proposed as a low cost technology demonstration mission, using a 2-micron, 100-mJ, 6-Hz, 25-cm, coherent lidar system based on demonstrated technology. SPARCLE was selected in late October 1997 to be NASA's New Millennium Program (NMP) second earth-observing (EO-2) mission. To maximize the success probability of SPARCLE, NASA/MSFC desired expert guidance in the areas of coherent laser radar (CLR) theory, CLR wind measurement, fielding of CLR systems, CLR alignment validation, and space lidar experience. This led to the formation of the NASA/MSFC Coherent Lidar Technology Advisory Team (CLTAT) in December 1997. A threefold purpose for the advisory team was identified as: 1) guidance to the SPARCLE mission, 2) advice regarding the roadmap of post-SPARCLE coherent Doppler wind lidar (CDWL) space missions and the desired matching technology development plan 3, and 3) general coherent lidar theory, simulation, hardware, and experiment information exchange. The current membership of the CLTAT is shown. Membership does not result in any NASA or other funding at this time. We envision the business of the CLTAT to be conducted mostly by email, teleconference, and occasional meetings. The three meetings of the CLTAT to date, in Jan. 1998, July 1998, and Jan. 1999, have all been collocated with previously scheduled meetings of the Working Group on Space-Based Lidar Winds. The meetings have been very productive. Topics discussed include the SPARCLE technology validation plan including pre-launch end-to-end testing, the space-based wind mission roadmap beyond SPARCLE and its implications on the resultant technology development, the current values and proposed future advancement in lidar system efficiency, and the difference between using single-mode fiber optical mixing vs. the traditional free space optical mixing. attitude information from lidar and non-lidar sensors, and pointing knowledge algorithms will meet this second requirement. The topic of this paper is the pre-launch demonstration of the first requirement, adequate sensitivity of the SPARCLE lidar.

Lidar on small UAV for 3D mapping

NASA Astrophysics Data System (ADS)

Tulldahl, H. Michael; Larsson, Hâkan

2014-10-01

Small UAV:s (Unmanned Aerial Vehicles) are currently in an explosive technical development phase. The performance of UAV-system components such as inertial navigation sensors, propulsion, control processors and algorithms are gradually improving. Simultaneously, lidar technologies are continuously developing in terms of reliability, accuracy, as well as speed of data collection, storage and processing. The lidar development towards miniature systems with high data rates has, together with recent UAV development, a great potential for new three dimensional (3D) mapping capabilities. Compared to lidar mapping from manned full-size aircraft a small unmanned aircraft can be cost efficient over small areas and more flexible for deployment. An advantage with high resolution lidar compared to 3D mapping from passive (multi angle) photogrammetry is the ability to penetrate through vegetation and detect partially obscured targets. Another advantage is the ability to obtain 3D data over the whole survey area, without the limited performance of passive photogrammetry in low contrast areas. The purpose of our work is to demonstrate 3D lidar mapping capability from a small multirotor UAV. We present the first experimental results and the mechanical and electrical integration of the Velodyne HDL-32E lidar on a six-rotor aircraft with a total weight of 7 kg. The rotating lidar is mounted at an angle of 20 degrees from the horizontal plane giving a vertical field-of-view of 10-50 degrees below the horizon in the aircraft forward directions. For absolute positioning of the 3D data, accurate positioning and orientation of the lidar sensor is of high importance. We evaluate the lidar data position accuracy both based on inertial navigation system (INS) data, and on INS data combined with lidar data. The INS sensors consist of accelerometers, gyroscopes, GPS, magnetometers, and a pressure sensor for altimetry. The lidar range resolution and accuracy is documented as well as the capability for target surface reflectivity estimation based on measurements on calibration standards. Initial results of the general mapping capability including the detection through partly obscured environments is demonstrated through field data collection and analysis.

A Numerical Model of the Performance of the Howard University Raman Lidar System

NASA Astrophysics Data System (ADS)

Connell, Rasheen M.; Adam, Mariana; Venable, Demetrius

2009-07-01

At the Howard University Atmospheric Observatory in Beltsville, MD, a Raman Lidar system was developed to provide both daytime and nighttime measurements of water vapor, aerosols, and cirrus clouds with 1 min temporal and 7.5 m spatial resolution in the lower troposphere. Signals at three wavelengths associated with Rayleigh/Mie scattering for aerosols and cirrus clouds at 354.7 nm, Raman scattering for nitrogen at 386.7 nm, and water vapor at 407.5 nm are analyzed. The transmitter is a triple harmonic Nd: YAG solid state laser. The receiver is a 40 cm Cassegrain telescope. Our detector system consists of a multi-channel wavelength separator unit and data acquisition system. We are developing a numerical model to provide a realistic representation of the system behavior. The variants of the lidar equation in the model use system parameters and are solved to determine the return signals for our lidar system. In this paper, we report on two of the five case studies being investigated: clear sky and cirrus cloud covered molecular atmosphere. The first simulations are based on a standard atmosphere, which assumes an unpolluted (aerosol-free) dry air atmosphere. The second set of simulations is based on a cloudy atmosphere, where cirrus clouds are added to the conditions in case study I. Lidar signals are simulated over the altitude range covered by our measurements (up to 14 km). Results will show comparisons between the simulated and actual measurements when varying lidar and atmospheric optical parameters in the model.

Challenges in miniaturized automotive long-range lidar system design

NASA Astrophysics Data System (ADS)

Fersch, Thomas; Weigel, Robert; Koelpin, Alexander

2017-05-01

This paper discusses the current technical limitations posed on endeavors to miniaturize lidar systems for use in automotive applications and how to possibly extend those limits. The focus is set on long-range scanning direct time of flight LiDAR systems using APD photodetectors. Miniaturization evokes severe problems in ensuring absolute laser safety while maintaining the systems' performance in terms of maximum range, signal-to-noise ratio, detection probability, pixel density, or frame rate. Based on hypothetical but realistic specifications for an exemplary system the complete lidar signal path is calculated. The maximum range of the system is used as a general performance indicator. It is determined with the minimum signal-to-noise ratio required to detect an object. Various system parameters are varied to find their impact on the system's range. The reduction of the laser's pulse width and the right choice for the transimpedance amplifier's amplification have shown to be practicable measures to double the system's range.

Performance of Planar-Waveguide External Cavity Laser for Precision Measurements

NASA Technical Reports Server (NTRS)

Numata, Kenji; Camp, Jordan; Krainak, Michael A.; Stolpner, Lew

2010-01-01

A 1542-nm planar-waveguide external cavity laser (PW-ECL) is shown to have a sufficiently low level of frequency and intensity noise to be suitable for precision measurement applications. The frequency noise and intensity noise of the PW-ECL was comparable or better than the nonplanar ring oscillator (NPRO) and fiber laser between 0.1 mHz to 100 kHz. Controllability of the PW-ECL was demonstrated by stabilizing its frequency to acetylene (13C2H2) at 10(exp -13) level of Allan deviation. The PW-ECL also has the advantage of the compactness of a standard butterfly package, low cost, and a simple design consisting of a semiconductor gain media coupled to a planar-waveguide Bragg reflector. These features would make the PW-ECL suitable for precision measurements, including compact optical frequency standards, space lidar, and space interferometry

Network of LAMP systems for atmospheric monitoring in India

NASA Astrophysics Data System (ADS)

Yellapragada, Bhavani Kumar; Jayaraman, Achuthan

2012-07-01

A systematic knowledge of the vertical distribution of aerosol particles in the atmosphere is required for understanding many atmospheric processes such as dynamics of boundary layer, pollution transport, modification of cloud microphysics etc. At present, the information on the particle distribution in the atmosphere is far from sufficient to estimate properly the load of aerosols in the atmosphere. Light detection and ranging (LIDAR) has been demonstrated to be a reliable remote sensing technique to obtain altitude profiles of atmospheric cloud and aerosol scattering. A LIDAR network is being implemented by National Atmospheric Research Laboratory (NARL), a Department of Space unit, in India for the measurement and monitoring of the atmospheric aerosols and clouds. Towards this, the technology of boundary layer lidar (BLL) (Bhavani Kumar, 2006) has been exploited. Several industrial grade BLL systems are being fabricated at a private industry in India through technological transfer from NARL. The industrial BLL lidar is named as LAMP, stands for LIDAR for Atmospheric Measurement and Probing. Five LAMP systems have already been fabricated and deployed at several locations of the country for continuous monitoring of aerosols and clouds under the Indian Lidar network (I-LINK) programme. The LAMP system employs a single barrel construction so that no realignment is required in future. Moreover, the network lidar system employs several features like rotation facility about the elevation (EL) axis, a provision of front window for environmental protection to the telescope optics and a silica gel pocket for desiccation (for transmit and receive assembly) and a provision of nitrogen purging to overcome the humidity effects. The LAMP system is an autonomous system equipped with a diode pumped Nd-YAG laser, a PMT for the detection of the backscattered photons, and a PC based photon counting electronics for recording the photon returns. In this paper, a report describing LAMP hardware components, acceptance test results and sample atmospheric measurements obtained from different locations across the country will be presented. Reference Bhavani Kumar, Y., Portable lidar system for atmospheric boundary layer measurements, Opt. Eng., 45, 076201, 2006 (doi: 10.1117/1.2221555)

Eye Safe, Visible Wavelength Lidar Systems: Design and Operational Advances, Results and Potential

NASA Technical Reports Server (NTRS)

Spinhirne, James; Welton, Ellsworth J.; Berkoff, Timothy; Campbell, James

2007-01-01

In the early nineties the first of the eye safe visible wavelength lidar systems known now as Micro Pulse Lidar (MPL) became operational. The important advance of the design was a system that, unlike most existing lidar, operated at eye safe energy densities and could thus operate unattended for full time monitoring. Since that time there have been many dozens of these systems produced and applied for full time profiling of atmospheric cloud and aerosol structure. There is currently an observational network of MPL sites to support global climate research. In thc course of application of these instruments there have been significant improvements in the, design and performance of the systems. In the last half decade particularly there has been significant application and technical development of MPL systems. In this paper we review progress. The current MPL systems in use are all single wavelength systems designed for cloud and aerosol applications. For the cloud and aerosol applications, both lidar depolarization and multi wavelength measurements have significant applications. These can be accomplished with the MPL, approach. The main current challenge for the lidar network activity are in the area of the reliability, repeatability and efficiency of data processing. The network makes use of internet data downloads and automated processing. The heights of all cloud and aerosol layers are needed. The recent emphasis has been in operationally deriving aerosol extinction cross section. Future emphasis will include adding cirrus optical parameters. For operational effectiveness, improvements to simplify routine data signal calibration are being researched. Overall the MPL systems have proven very effective. A large data base of results from globally distributed sites can be easily accessed through the internet. Applications have included atmospheric model development. Validation of current global satellite observations of aerosol and clouds, including now orbital lidar observations, was a primary goal for NASA. Although sampling issues require careful consideration, results have proven useful.

Application of the Doppler lidar system to agricultural burning and air-sea interactions

NASA Technical Reports Server (NTRS)

Fitzjarrald, D.

1980-01-01

The Doppler lidar system is potentially a very powerful measurement system. Three areas concerning the system are discussed: (1) error analysis of the system to verify the results; (2) application of the system to agricultural burning in California central valley; and (3) oceanographic possibilities of the system.

Windshear avoidance - Requirements and proposed system for airborne lidar detection

NASA Technical Reports Server (NTRS)

Targ, Russell; Bowles, Roland L.

1988-01-01

A generalized windshear hazard index is derived from considerations of wind conditions and an aircraft's present and potential altitude. Based on a systems approach to the windshear threat, lidar appears to be a viable methodology for windshear detection and avoidance, even in conditions of moderately heavy precipitation. The airborne CO2 and Ho:YAG lidar windshear detection systems analyzed can each give the pilot information about the line-of-sight component of windshear threat from his present position to a region extending 1 to 3 km in front of the aircraft. This constitutes a warning time of 15 to 45 s. The technology necessary to design, build and test such a brassboard 10.6-micron CO2 lidar is at hand.

Development of Lidar Sensor Systems for Autonomous Safe Landing on Planetary Bodies

NASA Technical Reports Server (NTRS)

Amzajerdian, Farzin; Pierottet, Diego F.; Petway, Larry B.; Vanek, Michael D.

2010-01-01

Lidar has been identified by NASA as a key technology for enabling autonomous safe landing of future robotic and crewed lunar landing vehicles. NASA LaRC has been developing three laser/lidar sensor systems under the ALHAT project. The capabilities of these Lidar sensor systems were evaluated through a series of static tests using a calibrated target and through dynamic tests aboard helicopters and a fixed wing aircraft. The airborne tests were performed over Moon-like terrain in the California and Nevada deserts. These tests provided the necessary data for the development of signal processing software, and algorithms for hazard detection and navigation. The tests helped identify technology areas needing improvement and will also help guide future technology advancement activities.

Measurement of Spray Drift with a Specifically Designed Lidar System.

PubMed

Gregorio, Eduard; Torrent, Xavier; Planas de Martí, Santiago; Solanelles, Francesc; Sanz, Ricardo; Rocadenbosch, Francesc; Masip, Joan; Ribes-Dasi, Manel; Rosell-Polo, Joan R

2016-04-08

Field measurements of spray drift are usually carried out by passive collectors and tracers. However, these methods are labour- and time-intensive and only provide point- and time-integrated measurements. Unlike these methods, the light detection and ranging (lidar) technique allows real-time measurements, obtaining information with temporal and spatial resolution. Recently, the authors have developed the first eye-safe lidar system specifically designed for spray drift monitoring. This prototype is based on a 1534 nm erbium-doped glass laser and an 80 mm diameter telescope, has scanning capability, and is easily transportable. This paper presents the results of the first experimental campaign carried out with this instrument. High coefficients of determination (R² > 0.85) were observed by comparing lidar measurements of the spray drift with those obtained by horizontal collectors. Furthermore, the lidar system allowed an assessment of the drift reduction potential (DRP) when comparing low-drift nozzles with standard ones, resulting in a DRP of 57% (preliminary result) for the tested nozzles. The lidar system was also used for monitoring the evolution of the spray flux over the canopy and to generate 2-D images of these plumes. The developed instrument is an advantageous alternative to passive collectors and opens the possibility of new methods for field measurement of spray drift.

The NASA/MSFC Coherent Lidar Technology Advisory Team

NASA Technical Reports Server (NTRS)

Kavaya, Michael J.

1999-01-01

The SPAce Readiness Coherent Lidar Experiment (SPARCLE) mission was proposed as a low cost technology demonstration mission, using a 2-micron, 100-mJ, 6-Hz, 25-cm, coherent lidar system based on demonstrated technology. SPARCLE was selected in late October 1997 to be NASA's New Millennium Program (NMP) second earth-observing (EO-2) mission. To maximize the success probability of SPARCLE, NASA/MSFC desired expert guidance in the areas of coherent laser radar (CLR) theory, CLR wind measurement, fielding of CLR systems, CLR alignment validation, and space lidar experience. This led to the formation of the NASA/MSFC Coherent Lidar Technology Advisory Team (CLTAT) in December 1997. A threefold purpose for the advisory team was identified as: 1) guidance to the SPARCLE mission, 2) advice regarding the roadmap of post-SPARCLE coherent Doppler wind lidar (CDWL) space missions and the desired matching technology development plan 3, and 3) general coherent lidar theory, simulation, hardware, and experiment information exchange. The current membership of the CLTAT is shown. Membership does not result in any NASA or other funding at this time. We envision the business of the CLTAT to be conducted mostly by email, teleconference, and occasional meetings. The three meetings of the CLTAT to date, in Jan. 1998, July 1998, and Jan. 1999, have all been collocated with previously scheduled meetings of the Working Group on Space-Based Lidar Winds. The meetings have been very productive. Topics discussed include the SPARCLE technology validation plan including pre-launch end-to-end testing, the space-based wind mission roadmap beyond SPARCLE and its implications on the resultant technology development, the current values and proposed future advancement in lidar system efficiency, and the difference between using single-mode fiber optical mixing vs. the traditional free space optical mixing.

A preliminary study of air-pollution measurement by active remote-sensing techniques

NASA Technical Reports Server (NTRS)

Wright, M. L.; Proctor, E. K.; Gasiorek, L. S.; Liston, E. M.

1975-01-01

Air pollutants are identified, and the needs for their measurement from satellites and aircraft are discussed. An assessment is made of the properties of these pollutants and of the normal atmosphere, including interactions with light of various wavelengths and the resulting effects on transmission and scattering of optical signals. The possible methods for active remote measurement are described; the relative performance capabilities of double-ended and single-ended systems are compared qualitatively; and the capabilities of the several single-ended or backscattering techniques are compared quantitatively. The differential-absorption lidar (DIAL) technique is shown to be superior to the other backscattering techniques. The lidar system parameters and their relationships to the environmental factors and the properties of pollutants are examined in detail. A computer program that models both the atmosphere (including pollutants) and the lidar system is described. The performance capabilities of present and future lidar components are assessed, and projections are made of prospective measurement capabilities for future lidar systems. Following a discussion of some important operational factors that affect both the design and measurement capabilities of airborne and satellite-based lidar systems, the extensive analytical results obtained through more than 1000 individual cases analyzed with the aid of the computer program are summarized and discussed. The conclusions are presented. Recommendations are also made for additional studies to investigate cases that could not be explored adequately during this study.

Does the Coherent Lidar System Corroborate Non-Interaction of Waves (NIW)?

NASA Technical Reports Server (NTRS)

Prasad, Narasimha S.; Roychoudhari, Chandrasekhar

2013-01-01

The NIW (non-interaction of waves) property has been proposed by one of the coauthors. The NIW property states that in the absence of any "obstructing" detectors, all the Huygens-Fresnel secondary wavelets will continue to propagate unhindered and without interacting (interfering) with each other. Since a coherent lidar system incorporates complex behaviors of optical components with different polarizations including circular polarization for the transmitted radiation, then the question arises whether the NIW principle accommodate elliptical polarization of light. Elliptical polarization presumes the summation of orthogonally polarized electric field vectors which contradicts the NIW principle. In this paper, we present working of a coherent lidar system using Jones matrix formulation. The Jones matrix elements represent the anisotropic dipolar properties of molecules of optical components. Accordingly, when we use the Jones matrix methodology to analyze the coherent lidar system, we find that the system behavior is congruent with the NIW property.

Development of a regional LiDAR field plot strategy for Oregon and Washington

Treesearch

Arvind Bhuta; Leah Rathbun

2015-01-01

The National Forest System (NFS) Pacific Northwest Region (R6) has been flying LiDAR on a per project basis. Additional field data was also collected in situ to many of these LiDAR projects to aid in the development of predictive models and estimate values which are unattainable through LiDAR data alone (e.g. species composition, tree volume, and downed woody material...

A General-purpose Framework for Parallel Processing of Large-scale LiDAR Data

NASA Astrophysics Data System (ADS)

Li, Z.; Hodgson, M.; Li, W.

2016-12-01

Light detection and ranging (LiDAR) technologies have proven efficiency to quickly obtain very detailed Earth surface data for a large spatial extent. Such data is important for scientific discoveries such as Earth and ecological sciences and natural disasters and environmental applications. However, handling LiDAR data poses grand geoprocessing challenges due to data intensity and computational intensity. Previous studies received notable success on parallel processing of LiDAR data to these challenges. However, these studies either relied on high performance computers and specialized hardware (GPUs) or focused mostly on finding customized solutions for some specific algorithms. We developed a general-purpose scalable framework coupled with sophisticated data decomposition and parallelization strategy to efficiently handle big LiDAR data. Specifically, 1) a tile-based spatial index is proposed to manage big LiDAR data in the scalable and fault-tolerable Hadoop distributed file system, 2) two spatial decomposition techniques are developed to enable efficient parallelization of different types of LiDAR processing tasks, and 3) by coupling existing LiDAR processing tools with Hadoop, this framework is able to conduct a variety of LiDAR data processing tasks in parallel in a highly scalable distributed computing environment. The performance and scalability of the framework is evaluated with a series of experiments conducted on a real LiDAR dataset using a proof-of-concept prototype system. The results show that the proposed framework 1) is able to handle massive LiDAR data more efficiently than standalone tools; and 2) provides almost linear scalability in terms of either increased workload (data volume) or increased computing nodes with both spatial decomposition strategies. We believe that the proposed framework provides valuable references on developing a collaborative cyberinfrastructure for processing big earth science data in a highly scalable environment.

TOLNet ozone lidar intercomparison during the discover-aq and frappé campaigns

NASA Astrophysics Data System (ADS)

Newchurch, Michael J.; Alvarez, Raul J.; Berkoff, Timothy A.; Carrion, William; DeYoung, Russell J.; Ganoe, Rene; Gronoff, Guillaume; Kirgis, Guillaume; Kuang, Shi; Langford, Andy O.; Leblanc, Thierry; McGee, Thomas J.; Pliutau, Denis; Senff, Christoph; Sullivan, John T.; Sumnicht, Grant; Twigg, Laurence W.; Wang, Lihua

2018-04-01

The Tropospheric Ozone Lidar Network (TOLNet) is a unique network of lidar systems that measure atmospheric profiles of ozone and aerosols, to contribute to air-quality studies, atmospheric modeling, and satellite validation efforts. The accurate characterization of these lidars is of critical interest, and is necessary to determine cross-instrument calibration uniformity. From July to August 2014, three lidars, the TROPospheric OZone (TROPOZ) lidar, the Tunable Optical Profiler for Aerosol and oZone (TOPAZ) lidar, and the Langley Mobile Ozone Lidar (LMOL), of TOLNet participated in the "Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality" (DISCOVER-AQ) mission and the "Front Range Air Pollution and Photochemistry Éxperiment" (FRAPPÉ) to measure sub-hourly ozone variations from near the surface to the top of the troposphere. Although large differences occur at few individual altitudes in the near field and far field range, the TOLNet lidars agree with each other within ±4%. These results indicate excellent measurement accuracy for the TOLNet lidars that is suitable for use in air-quality and ozone modeling efforts.

Coherent Doppler lidar signal covariance including wind shear and wind turbulence

NASA Technical Reports Server (NTRS)

Frehlich, R. G.

1993-01-01

The performance of coherent Doppler lidar is determined by the statistics of the coherent Doppler signal. The derivation and calculation of the covariance of the Doppler lidar signal is presented for random atmospheric wind fields with wind shear. The random component is described by a Kolmogorov turbulence spectrum. The signal parameters are clarified for a general coherent Doppler lidar system. There are two distinct physical regimes: one where the transmitted pulse determines the signal statistics and the other where the wind field dominates the signal statistics. The Doppler shift of the signal is identified in terms of the wind field and system parameters.

3D pulsed chaos lidar system.

PubMed

Cheng, Chih-Hao; Chen, Chih-Ying; Chen, Jun-Da; Pan, Da-Kung; Ting, Kai-Ting; Lin, Fan-Yi

2018-04-30

We develop an unprecedented 3D pulsed chaos lidar system for potential intelligent machinery applications. Benefited from the random nature of the chaos, conventional CW chaos lidars already possess excellent anti-jamming and anti-interference capabilities and have no range ambiguity. In our system, we further employ self-homodyning and time gating to generate a pulsed homodyned chaos to boost the energy-utilization efficiency. Compared to the original chaos, we show that the pulsed homodyned chaos improves the detection SNR by more than 20 dB. With a sampling rate of just 1.25 GS/s that has a native sampling spacing of 12 cm, we successfully achieve millimeter-level accuracy and precision in ranging. Compared with two commercial lidars tested side-by-side, namely the pulsed Spectroscan and the random-modulation continuous-wave Lidar-lite, the pulsed chaos lidar that is in compliance with the class-1 eye-safe regulation shows significantly better precision and a much longer detection range up to 100 m. Moreover, by employing a 2-axis MEMS mirror for active laser scanning, we also demonstrate real-time 3D imaging with errors of less than 4 mm in depth.

Strategies for lidar characterization of particulates from point and area sources

NASA Astrophysics Data System (ADS)

Wojcik, Michael D.; Moore, Kori D.; Martin, Randal S.; Hatfield, Jerry

2010-10-01

Use of ground based remote sensing technologies such as scanning lidar systems (light detection and ranging) has gained traction in characterizing ambient aerosols due to some key advantages such as wide area of regard (10 km2), fast response time, high spatial resolution (<10 m) and high sensitivity. Energy Dynamics Laboratory and Utah State University, in conjunction with the USDA-ARS, has developed a three-wavelength scanning lidar system called Aglite that has been successfully deployed to characterize particle motion, concentration, and size distribution at both point and diffuse area sources in agricultural and industrial settings. A suite of massbased and size distribution point sensors are used to locally calibrate the lidar. Generating meaningful particle size distribution, mass concentration, and emission rate results based on lidar data is dependent on strategic onsite deployment of these point sensors with successful local meteorological measurements. Deployment strategies learned from field use of this entire measurement system over five years include the characterization of local meteorology and its predictability prior to deployment, the placement of point sensors to prevent contamination and overloading, the positioning of the lidar and beam plane to avoid hard target interferences, and the usefulness of photographic and written observational data.

The Novel Nonlinear Adaptive Doppler Shift Estimation Technique and the Coherent Doppler Lidar System Validation Lidar

NASA Technical Reports Server (NTRS)

Beyon, Jeffrey Y.; Koch, Grady J.

2006-01-01

The signal processing aspect of a 2-m wavelength coherent Doppler lidar system under development at NASA Langley Research Center in Virginia is investigated in this paper. The lidar system is named VALIDAR (validation lidar) and its signal processing program estimates and displays various wind parameters in real-time as data acquisition occurs. The goal is to improve the quality of the current estimates such as power, Doppler shift, wind speed, and wind direction, especially in low signal-to-noise-ratio (SNR) regime. A novel Nonlinear Adaptive Doppler Shift Estimation Technique (NADSET) is developed on such behalf and its performance is analyzed using the wind data acquired over a long period of time by VALIDAR. The quality of Doppler shift and power estimations by conventional Fourier-transform-based spectrum estimation methods deteriorates rapidly as SNR decreases. NADSET compensates such deterioration in the quality of wind parameter estimates by adaptively utilizing the statistics of Doppler shift estimate in a strong SNR range and identifying sporadic range bins where good Doppler shift estimates are found. The authenticity of NADSET is established by comparing the trend of wind parameters with and without NADSET applied to the long-period lidar return data.

EAARL-B coastal topography: eastern New Jersey, Hurricane Sandy, 2012: first surface

USGS Publications Warehouse

Wright, C. Wayne; Fredericks, Xan; Troche, Rodolfo J.; Klipp, Emily S.; Kranenburg, Christine J.; Nagle, David B.

2014-01-01

These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography datasets were produced by the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida. This project provides highly detailed and accurate datasets for a portion of the New Jersey coastline beachface, acquired pre-Hurricane Sandy on October 26, and post-Hurricane Sandy on November 1 and November 5, 2012. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar system, known as the second-generation Experimental Advanced Airborne Research Lidar (EAARL-B), was used during data acquisition. The EAARL-B system is a raster-scanning, waveform-resolving, green-wavelength (532-nm) lidar designed to map nearshore bathymetry, topography, and vegetation structure simultaneously. The EAARL-B sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, down-looking red-green-blue (RGB) and infrared (IR) digital cameras, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL-B platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL-B system. The resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or sub-aerial topography. Specialized filtering algorithms have been implemented to determine the "bare earth" under vegetation from a point cloud of last return elevations. For more information about similar projects, please visit the Lidar for Science and Resource Management Web site.

Pulsed Lidar Performance/Technical Maturity Assessment

NASA Technical Reports Server (NTRS)

Gimmestad, Gary G.; West, Leanne L.; Wood, Jack W.; Frehlich, Rod

2004-01-01

This report describes the results of investigations performed by the Georgia Tech Research Institute (GTRI) and the National Center for Atmospheric Research (NCAR) under a task entitled 'Pulsed Lidar Performance/Technical Maturity Assessment' funded by the Crew Systems Branch of the Airborne Systems Competency at the NASA Langley Research Center. The investigations included two tasks, 1.1(a) and 1.1(b). The Tasks discussed in this report are in support of the NASA Virtual Airspace Modeling and Simulation (VAMS) program and are designed to evaluate a pulsed lidar that will be required for active wake vortex avoidance solutions. The Coherent Technologies, Inc. (CTI) WindTracer LIDAR is an eye-safe, 2-micron, coherent, pulsed Doppler lidar with wake tracking capability. The actual performance of the WindTracer system was to be quantified. In addition, the sensor performance has been assessed and modeled, and the models have been included in simulation efforts. The WindTracer LIDAR was purchased by the Federal Aviation Administration (FAA) for use in near-term field data collection efforts as part of a joint NASA/FAA wake vortex research program. In the joint research program, a minimum common wake and weather data collection platform will be defined. NASA Langley will use the field data to support wake model development and operational concept investigation in support of the VAMS project, where the ultimate goal is to improve airport capacity and safety. Task 1.1(a), performed by NCAR in Boulder, Colorado to analyze the lidar system to determine its performance and capabilities based on results from simulated lidar data with analytic wake vortex models provided by NASA, which were then compared to the vendor's claims for the operational specifications of the lidar. Task 1.1(a) is described in Section 3, including the vortex model, lidar parameters and simulations, and results for both detection and tracking of wake vortices generated by Boeing 737s and 747s. Task 1.1(b) was performed by GTRI in Atlanta, Georgia and is described in Section 4. Task 1.1(b) includes a description of the St. Louis Airport (STL) field test being conducted by the Volpe National Transportation Systems Center, and it also addresses the development of a test plan to validate simulation studies conducted as part of Task 1.1(a). Section 4.2 provides a description of the Volpe STL field tests, and Section 4.3 describes 3 possible ways to validate the WindTracer lidar simulations performed in Task 1.1(a).

Estimating the vegetation canopy height using micro-pulse photon-counting LiDAR data.

PubMed

Nie, Sheng; Wang, Cheng; Xi, Xiaohuan; Luo, Shezhou; Li, Guoyuan; Tian, Jinyan; Wang, Hongtao

2018-05-14

The upcoming space-borne LiDAR satellite Ice, Cloud and land Elevation Satellite-2 (ICESat-2) is scheduled to launch in 2018. Different from the waveform LiDAR system onboard the ICESat, ICESat-2 will use a micro-pulse photon-counting LiDAR system. Thus new data processing algorithms are required to retrieve vegetation canopy height from photon-counting LiDAR data. The objective of this paper is to develop and validate an automated approach for better estimating vegetation canopy height. The new proposed method consists of three key steps: 1) filtering out the noise photons by an effective noise removal algorithm based on localized statistical analysis; 2) separating ground returns from canopy returns using an iterative photon classification algorithm, and then determining ground surface; 3) generating canopy-top surface and calculating vegetation canopy height based on canopy-top and ground surfaces. This automatic vegetation height estimation approach was tested to the simulated ICESat-2 data produced from Sigma Space LiDAR data and Multiple Altimeter Beam Experimental LiDAR (MABEL) data, and the retrieved vegetation canopy heights were validated by canopy height models (CHMs) derived from airborne discrete-return LiDAR data. Results indicated that the estimated vegetation canopy heights have a relatively strong correlation with the reference vegetation heights derived from airborne discrete-return LiDAR data (R 2 and RMSE values ranging from 0.639 to 0.810 and 4.08 m to 4.56 m respectively). This means our new proposed approach is appropriate for retrieving vegetation canopy height from micro-pulse photon-counting LiDAR data.

LIDAR vs. GEODAS land elevation data in hurricane induced inundation modelling

NASA Astrophysics Data System (ADS)

Peng, M.; Pietrafesa, L. J.; Bao, S.; Liu, H.; Xia, M.; Yan, T.

2007-04-01

LIDAR (Light Detection and Ranging) and GEODAS (GEOphysical DAta System) are respectively taken as the land elevation data for a 3-D storm surge and inundation model to investigate the subsequent inundation differences. Hilton Head, South Carolina, and Croatan-Albemarle-Pamlico Estuary System (CAPES), North Carolina, are the two investigated regions. Significant inundation differences with LIDAR versus GEODAS are found in both regions. The modeled inundation area with GEODAS is larger than with LIDAR. For Category 2-3 hypothetical hurricanes, the maximum inundation difference in Hilton Head region is 67%, while the difference in the CAPES is 156%. Generally, vertical precision difference of the two databases is the major reason for the inundation difference. Recently constructed man-made structures, not included in the GEODAS, but included in the LIDAR data sets may be another contributing reason.

2-Micron Triple-Pulse Integrated Path Differential Absorption Lidar Development for Simultaneous Airborne Column Measurements of Carbon Dioxide and Water Vapor in the Atmosphere

NASA Technical Reports Server (NTRS)

Singh, Upendra N.; Petros, Mulugeta; Refaat, Tamer F.; Yu, Jirong

2016-01-01

For more than 15 years, NASA Langley Research Center (LaRC) has contributed in developing several 2-micron carbon dioxide active remote sensors using the DIAL technique. Currently, an airborne 2-micron triple-pulse integrated path differential absorption (IPDA) lidar is under development at NASA LaRC. This paper focuses on the advancement of the 2-micron triple-pulse IPDA lidar development. Updates on the state-of-the-art triple-pulse laser transmitter will be presented including the status of wavelength control, packaging and lidar integration. In addition, receiver development updates will also be presented, including telescope integration, detection systems and data acquisition electronics. Future plan for IPDA lidar system for ground integration, testing and flight validation will be presented.

Airborne LiDAR reflective linear feature extraction for strip adjustment and horizontal accuracy determination.

DOT National Transportation Integrated Search

2009-02-01

ODOT's Office of Aerial Engineering (OAE) has been using an Opetch 30/70 ALTM airborne LiDAR system for about four years. The introduction of LiDAR technology was a major development towards improving the mapping operations. The overall experiences a...

Scanning elastic lidar observations of aerosol transport in New York City

NASA Astrophysics Data System (ADS)

Diaz, Adrian; Dominguez, Victor; Dobryansky, Selma; Wu, Yonghua; Arend, Mark; Vladutescu, Daniela Viviana; Gross, Barry; Moshary, Fred

2018-04-01

In this study, spatial distribution of aerosols in New York City is observed using a scanning eyesafe 532 nm elastic-backscatter micro-pulse lidar system. Observations show dynamics of the boundary layer and inhomogeneous distribution and transport of aerosols. The data acquired are complemented with simultaneous measurements of particulate matter and wind speed and direction. Furthermore, the system observations are validated by comparing them with a colocated multi-wavelength lidar.

Atmospheric lidar multi-user instrument system definition study

NASA Technical Reports Server (NTRS)

Greco, R. V. (Editor)

1980-01-01

A spaceborne lidar system for atmospheric studies was defined. The primary input was the Science Objectives Experiment Description and Evolutionary Flow Document. The first task of the study was to perform an experiment evolutionary analysis of the SEED. The second task was the system definition effort of the instrument system. The third task was the generation of a program plan for the hardware phase. The fourth task was the supporting studies which included a Shuttle deficiency analysis, a preliminary safety hazard analysis, the identification of long lead items, and development studies required. As a result of the study an evolutionary Lidar Multi-User Instrument System (MUIS) was defined. The MUIS occupies a full Spacelab pallet and has a weight of 1300 kg. The Lidar MUIS laser provides a 2 joule frequency doubled Nd:YAG laser that can also pump a tuneable dye laser wide frequency range and bandwidth. The MUIS includes a 1.25 meter diameter aperture Cassegrain receiver, with a moveable secondary mirror to provide precise alignment with the laser. The receiver can transmit the return signal to three single and multiple photomultiple tube detectors by use of a rotating fold mirror. It is concluded that the Lidar MUIS proceed to program implementation.

Aerosol Plume Detection Algorithm Based on Image Segmentation of Scanning Atmospheric Lidar Data

DOE PAGES

Weekley, R. Andrew; Goodrich, R. Kent; Cornman, Larry B.

2016-04-06

An image-processing algorithm has been developed to identify aerosol plumes in scanning lidar backscatter data. The images in this case consist of lidar data in a polar coordinate system. Each full lidar scan is taken as a fixed image in time, and sequences of such scans are considered functions of time. The data are analyzed in both the original backscatter polar coordinate system and a lagged coordinate system. The lagged coordinate system is a scatterplot of two datasets, such as subregions taken from the same lidar scan (spatial delay), or two sequential scans in time (time delay). The lagged coordinatemore » system processing allows for finding and classifying clusters of data. The classification step is important in determining which clusters are valid aerosol plumes and which are from artifacts such as noise, hard targets, or background fields. These cluster classification techniques have skill since both local and global properties are used. Furthermore, more information is available since both the original data and the lag data are used. Performance statistics are presented for a limited set of data processed by the algorithm, where results from the algorithm were compared to subjective truth data identified by a human.« less

Design and Demonstration of a Miniature Lidar System for Rover Applications

NASA Technical Reports Server (NTRS)

Robinson, Benjamin

2010-01-01

A basic small and portable lidar system for rover applications has been designed. It uses a 20 Hz Nd:YAG pulsed laser, a 4-inch diameter telescope receiver, a custom-built power distribution unit (PDU), and a custom-built 532 nm photomultiplier tube (PMT) to measure the lidar signal. The receiving optics have been designed, but not constructed yet. LabVIEW and MATLAB programs have also been written to control the system, acquire data, and analyze data. The proposed system design, along with some measurements, is described. Future work to be completed is also discussed.

Comparisons of Simultaneously Acquired Airborne Sfm Photogrammetry and Lidar

NASA Astrophysics Data System (ADS)

Larsen, C. F.

2014-12-01

Digital elevation models (DEMs) created using images from a consumer DSLR camera are compared against simultaneously acquired LiDAR on a number of airborne mapping projects across Alaska, California and Utah. The aircraft used is a Cessna 180, and is equipped with the University of Alaska Geophysical Institute (UAF-GI) scanning airborne LiDAR system. This LiDAR is the same as described in Johnson et al, 2013, and is the principal instrument used for NASA's Operation IceBridge flights in Alaska. The system has been in extensive use since 2009, and is particularly well characterized with dozens of calibration flights and a careful program of boresight angle determination and monitoring. The UAF-GI LiDAR has a precision of +/- 8 cm and accuracy of +/- 15 cm. The photogrammetry DEM simultaneously acquired with the LiDAR relies on precise shutter timing using an event marker input to the IMU associated with the LiDAR system. The photo positions are derived from the fully coupled GPS/IMU processing, which samples at 100 Hz and is able to directly calculate the antenna to image plane offset displacements from the full orientation data. This use of the GPS/IMU solution means that both the LiDAR and Cessna 180 photogrammetry DEM share trajectory input data, however no orientation data nor ground control is used for the photorammetry processing. The photogrammetry DEMs are overlaid on the LiDAR point cloud and analyzed for horizontal shifts or warps relative to the LiDAR. No warping or horizontal shifts have been detectable for a number of photogrammetry DEMs. Vertical offsets range from +/- 30 cm, with a typical standard deviation about that mean of 10 cm or better. LiDAR and photogrammetry function inherently differently over trees and brush, and direct comparisons between the two methods show much larger differences over vegetated areas. Finally, the differences in flight patterns associated with the two methods will be discussed, highlighting the photogrammetry requirements for a well planned grid pattern and the effects of significant end lap and side lap in the imagery coverage.

Single-pass Airborne InSAR for Wide-swath, High-Resolution Cryospheric Surface Topography Mapping

NASA Astrophysics Data System (ADS)

Moller, D.; Hensley, S.; Wu, X.; Muellerschoen, R.

2014-12-01

In May 2009 a mm-wave single-pass interferometric synthetic aperture radar (InSAR) for the first time demonstrated ice surface topography swath-mapping in Greenland. This was achieved with the airborne Glacier and Ice Surface Topography Interferometer (GLISTIN-A). Ka-band (35.6GHz) was chosen for high-precision topographic mapping from a compact sensor with minimal surface penetration. In recent years, the system was comprehensively upgraded for improved performance, stability and calibration. In April 2013, after completing the upgrades, GLISTIN-A flew a brief campaign to Alaska. The primary purpose was to demonstrate the InSAR's ability to generate high-precision, high resolution maps of ice surface topography with swaths in excess of 10km. Comparison of GLISTIN-A's elevations over glacial ice with lidar verified the precision requirements and established elevation accuracies to within 2 m without tie points. Feature tracking of crevasses on Columbia Glacier using data acquired with a 3-day separation exhibit an impressive velocity mapping capability. Furthermore, GLISTIN-A flew over the Beaufort sea to determine if we could not only map sea ice, but also measure freeboard. Initial analysis has established we can measure sea-ice freeboard using height differences from the top of the sea-ice and the sea surface in open leads. In the future, a campaign with lidar is desired for a quantitative validation. Another proof-of-concept collection mapped snow-basins for hydrology. Snow depth measurements using summer and winter collections in the Sierras were compared with lidar measurements. Unsurprisingly when present, trees complicate the interpretation, but additional filtering and processing is in work. For each application, knowledge of the interferometric penetration is important for scientific interpretation. We present analytical predictions and experimental data to upper bound the elevation bias of the InSAR measurements over snow and snow-covered ice.

315mJ, 2-micrometers Double-Pulsed Coherent Differential Absorption Lidar Transmitter for Atmospheric CO2 Sensing

NASA Technical Reports Server (NTRS)

Yu, Jirong; Trieu, Bo; Bai, Yingxin; Koch, Grady; Chen, Songsheng; Petzar, Paul; Singh, Upendra N.; Kavaya, Michael J.; Beyon, Jeffrey

2010-01-01

The design of a double pulsed, injection seeded, 2-micrometer compact coherent Differential absorption Lidar (DIAL) transmitter for CO2 sensing is presented. This system is hardened for ground and airborne applications. The design architecture includes three continuous wave lasers which provide controlled on and off line seeding, injection seeded power oscillator and a single amplifier operating in double pass configuration. As the derivative a coherent Doppler wind lidar, this instrument has the added benefit of providing wind information. The active laser material used for this application is a Ho: Tm:YLF crystal operates at the eye-safe wavelength. The 3-meter long folded ring resonator produces energy of 130-mJ (90/40) with a temporal pulse length around 220 nanoseconds and 530 nanosecond pulses for on and off lines respectively. The separation between the two pulses is on the order of 200 microseconds. The line width is in the order of 2.5MHz and the beam quality has an M(sup 2) of 1.1 times diffraction limited beam. A final output energy for a pair of both on and off pulses as high as 315 mJ (190/125) at a repetition rate of 10 Hz is achieved. The operating temperature is set around 20 C for the pump diode lasers and 10 C for the rod. Since the laser design has to meet high-energy as well as high beam quality requirements, close attention is paid to the laser head design to avoid thermal distortion in the rod. A side-pumped configuration is used and heat is removed uniformly by passing coolant through a tube slightly larger than the rod to reduce thermal gradient. This paper also discusses the advantage of using a long upper laser level life time laser crystal for DIAL application. In addition issues related to injection seeding with two different frequencies to achieve a transform limited line width will be presented.

Multi-beam and single-chip LIDAR with discrete beam steering by digital micromirror device

NASA Astrophysics Data System (ADS)

Rodriguez, Joshua; Smith, Braden; Hellman, Brandon; Gin, Adley; Espinoza, Alonzo; Takashima, Yuzuru

2018-02-01

A novel Digital Micromirror Device (DMD) based beam steering enables a single chip Light Detection and Ranging (LIDAR) system for discrete scanning points. We present increasing number of scanning point by using multiple laser diodes for Multi-beam and Single-chip DMD-based LIDAR.

Airborne LiDAR reflective linear feature extraction for strip adjustment and horizontal accuracy determination : executive summary.

DOT National Transportation Integrated Search

2009-02-01

The Office of Aerial Engineering (OAE) has been : using an Optech 30/70 ALTM airborne LiDAR system : for about four years. The introduction of LiDAR : technology was a major development towards : improving the mapping operations, and the overall : ex...

Voxel-Based 3-D Tree Modeling from Lidar Images for Extracting Tree Structual Information

NASA Astrophysics Data System (ADS)

Hosoi, F.

2014-12-01

Recently, lidar (light detection and ranging) has been used to extracting tree structural information. Portable scanning lidar systems can capture the complex shape of individual trees as a 3-D point-cloud image. 3-D tree models reproduced from the lidar-derived 3-D image can be used to estimate tree structural parameters. We have proposed the voxel-based 3-D modeling for extracting tree structural parameters. One of the tree parameters derived from the voxel modeling is leaf area density (LAD). We refer to the method as the voxel-based canopy profiling (VCP) method. In this method, several measurement points surrounding the canopy and optimally inclined laser beams are adopted for full laser beam illumination of whole canopy up to the internal. From obtained lidar image, the 3-D information is reproduced as the voxel attributes in the 3-D voxel array. Based on the voxel attributes, contact frequency of laser beams on leaves is computed and LAD in each horizontal layer is obtained. This method offered accurate LAD estimation for individual trees and woody canopy trees. For more accurate LAD estimation, the voxel model was constructed by combining airborne and portable ground-based lidar data. The profiles obtained by the two types of lidar complemented each other, thus eliminating blind regions and yielding more accurate LAD profiles than could be obtained by using each type of lidar alone. Based on the estimation results, we proposed an index named laser beam coverage index, Ω, which relates to the lidar's laser beam settings and a laser beam attenuation factor. It was shown that this index can be used for adjusting measurement set-up of lidar systems and also used for explaining the LAD estimation error using different types of lidar systems. Moreover, we proposed a method to estimate woody material volume as another application of the voxel tree modeling. In this method, voxel solid model of a target tree was produced from the lidar image, which is composed of consecutive voxels that filled the outer surface and the interior of the stem and large branches. From the model, the woody material volume of any part of the target tree can be directly calculated easily by counting the number of corresponding voxels and multiplying the result by the per-voxel volume.

Lidar instruments for ESA Earth observation missions

NASA Astrophysics Data System (ADS)

Hélière, Arnaud; Armandillo, Errico; Durand, Yannig; Culoma, Alain; Meynart, Roland

2017-11-01

The idea of deploying a lidar system on an Earthorbiting satellite stems from the need for continuously providing profiles of our atmospheric structure with high accuracy and resolution and global coverage. Interest in this information for climatology, meteorology and the atmospheric sciences in general is huge. Areas of application range from the determination of global warming and greenhouse effects, to monitoring the transport and accumulation of pollutants in the different atmospheric regions (such as the recent fires in Southeast Asia), to the assessment of the largely unknown microphysical properties and the structural dynamics of the atmosphere itself. Spaceborne lidar systems have been the subject of extensive investigations by the European Space Agency since mid 1970's, resulting in mission and instrument concepts, such as ATLID, the cloud backscatter lidar payload of the EarthCARE mission, ALADIN, the Doppler wind lidar of the Atmospheric Dynamics Mission (ADM) and more recently a water vapour Differential Absorption Lidar considered for the WALES mission. These studies have shown the basic scientific and technical feasibility of spaceborne lidars, but they have also demonstrated their complexity from the instrument viewpoint. As a result, the Agency undertook technology development in order to strengthen the instrument maturity. This is the case for ATLID, which benefited from a decade of technology development and supporting studies and is now studied in the frame of the EarthCARE mission. ALADIN, a Direct Detection Doppler Wind Lidar operating in the Ultra -Violet, will be the 1st European lidar to fly in 2007 as payload of the Earth Explorer Core Mission ADM. WALES currently studied at the level of a phase A, is based upon a lidar operating at 4 wavelengths in near infrared and aims to profile the water vapour in the lower part of the atmosphere with high accuracy and low bias. Lastly, the European Space Agency is extending the lidar instrument field for Earth Observation by initiating feasibility studies of a spaceborne concept to monitor atmospheric CO2 and other greenhouse gases. The purpose of this paper is to present the instruments concept and related technology/instrument developments that are currently running at the European Space Agency. The paper will also outline the development planning proposed for future lidar systems.

CO2 lidar for measurements of trace gases and wind velocities

NASA Technical Reports Server (NTRS)

Hess, R. V.

1982-01-01

CO2 lidar systems technology and signal processing requirements relevant to measurement needs and sensitivity are discussed. Doppler processing is similar to microwave radar, with signal reception controlled by a computer capable of both direct and heterodyne operations. Trace gas concentrations have been obtained with the NASA DIAL system, and trace gas transport has been determined with Doppler lidar measurements for wind velocity and turbulence. High vertical resolution measurement of trace gases, wind velocity, and turbulence are most important in the planetary boundary layer and in regions between the PBL and the lower stratosphere. Shear measurements are critical for airport operational safety. A sensitivity analysis for heterodyne detection with the DIAL system and for short pulses using a Doppler lidar system is presented. The development of transient injection locking techniques, as well as frequency stability by reducing chirp and catalytic control of closed cycle CO2 laser chemistry, is described.

Preliminary Observing System Simulation Experiments for Doppler Wind Lidars Deployed on the International Space Station

NASA Technical Reports Server (NTRS)

Kemp, E.; Jacob, J.; Rosenberg, R.; Jusem, J. C.; Emmitt, G. D.; Wood, S.; Greco, L. P.; Riishojgaard, L. P.; Masutani, M.; Ma, Z.;

Advanced Opto-Electronics (LIDAR and Microsensor Development)

NASA Technical Reports Server (NTRS)

Vanderbilt, Vern C. (Technical Monitor); Spangler, Lee H.

2005-01-01

Our overall intent in this aspect of the project were to establish a collaborative effort between several departments at Montana State University for developing advanced optoelectronic technology for advancing the state-of-the-art in optical remote sensing of the environment. Our particular focus was on development of small systems that can eventually be used in a wide variety of applications that might include ground-, air-, and space deployments, possibly in sensor networks. Specific objectives were to: 1) Build a field-deployable direct-detection lidar system for use in measurements of clouds, aerosols, fish, and vegetation; 2) Develop a breadboard prototype water vapor differential absorption lidar (DIAL) system based on highly stable, tunable diode laser technology developed previously at MSU. We accomplished both primary objectives of this project, in developing a field-deployable direct-detection lidar and a breadboard prototype of a water vapor DIAL system. Paper summarizes each of these accomplishments.

Comparison of LIDAR system performance for alternative single-mode receiver architectures: modeling and experimental validation

NASA Astrophysics Data System (ADS)

Toliver, Paul; Ozdur, Ibrahim; Agarwal, Anjali; Woodward, T. K.

2013-05-01

In this paper, we describe a detailed performance comparison of alternative single-pixel, single-mode LIDAR architectures including (i) linear-mode APD-based direct-detection, (ii) optically-preamplified PIN receiver, (iii) PINbased coherent-detection, and (iv) Geiger-mode single-photon-APD counting. Such a comparison is useful when considering next-generation LIDAR on a chip, which would allow one to leverage extensive waveguide-based structures and processing elements developed for telecom and apply them to small form-factor sensing applications. Models of four LIDAR transmit and receive systems are described in detail, which include not only the dominant sources of receiver noise commonly assumed in each of the four detection limits, but also additional noise terms present in realistic implementations. These receiver models are validated through the analysis of detection statistics collected from an experimental LIDAR testbed. The receiver is reconfigurable into four modes of operation, while transmit waveforms and channel characteristics are held constant. The use of a diffuse hard target highlights the importance of including speckle noise terms in the overall system analysis. All measurements are done at 1550 nm, which offers multiple system advantages including less stringent eye safety requirements and compatibility with available telecom components, optical amplification, and photonic integration. Ultimately, the experimentally-validated detection statistics can be used as part of an end-to-end system model for projecting rate, range, and resolution performance limits and tradeoffs of alternative integrated LIDAR architectures.

Coherent lidar wind measurements from the Space Station base using 1.5 m all-reflective optics

NASA Technical Reports Server (NTRS)

Bilbro, J. W.; Beranek, R. G.

1987-01-01

This paper discusses the space-based measurement of atmospheric winds from the point of view of the requirements of the optical system of a coherent CO2 lidar. A brief description of the measurement technique is given and a discussion of previous study results provided. The telescope requirements for a Space Station based lidar are arrived at through discussions of the desired system sensitivity and the need for lag angle compensation.

Diffuse sunlight based calibration of the water vapor channel in the upc raman lidar

NASA Astrophysics Data System (ADS)

Muñoz-Porcar, Constantino; Comeron, Adolfo; Sicard, Michaël; Barragan, Ruben; Garcia-Vizcaino, David; Rodríguez-Gómez, Alejandro; Rocadenbosch, Francesc

2018-04-01

A method for determining the calibration factor of the water vapor channel of a Raman lidar, based on zenith measurements of diffuse sunlight and on assumptions regarding some system parameters and Raman scattering models, has been applied to the lidar system of Universitat Politècnica de Catalunya (UPC; Technical University of Catalonia, Spain). Results will be analyzed in terms of stability and comparison with typical methods relying on simultaneous radiosonde measurements.

Broadband Lidar Technique for Precision CO2 Measurement

NASA Technical Reports Server (NTRS)

Heaps, William S.

2008-01-01

Presented are preliminary experimental results, sensitivity measurements and discuss our new CO2 lidar system under development. The system is employing an erbium-doped fiber amplifier (EDFA), superluminescent light emitting diode (SLED) as a source and our previously developed Fabry-Perot interferometer subsystem as a detector part. Global measurement of carbon dioxide column with the aim of discovering and quantifying unknown sources and sinks has been a high priority for the last decade. The goal of Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission is to significantly enhance the understanding of the role of CO2 in the global carbon cycle. The National Academy of Sciences recommended in its decadal survey that NASA put in orbit a CO2 lidar to satisfy this long standing need. Existing passive sensors suffer from two shortcomings. Their measurement precision can be compromised by the path length uncertainties arising from scattering within the atmosphere. Also passive sensors using sunlight cannot observe the column at night. Both of these difficulties can be ameliorated by lidar techniques. Lidar systems present their own set of problems however. Temperature changes in the atmosphere alter the cross section for individual CO2 absorption features while the different atmospheric pressures encountered passing through the atmosphere broaden the absorption lines. Currently proposed lidars require multiple lasers operating at multiple wavelengths simultaneously in order to untangle these effects. The current goal is to develop an ultra precise, inexpensive new lidar system for precise column measurements of CO2 changes in the lower atmosphere that uses a Fabry-Perot interferometer based system as the detector portion of the instrument and replaces the narrow band laser commonly used in lidars with the newly available high power SLED as the source. This approach reduces the number of individual lasers used in the system from three or more to one - considerably reducing the risk of failure. It also tremendously reduces the requirement for wavelength stability in the source putting this responsibility instead on the Fabry-Perot subsystem.

Differential Absorption Lidar to Measure Sub-Hourly Variation of Tropospheric Ozone Profiles

NASA Technical Reports Server (NTRS)

Kuang, Shi; Burris, John F.; Newchurch, Michael J.; Johnson, Steve; Long, Stephanie

2009-01-01

A tropospheric ozone Differential Absorption Lidar (DIAL) system, developed jointly by the University of Alabama at Huntsville and NASA, is making regular observations of ozone vertical distributions between 1 and 8 km with two receivers under both daytime and nighttime conditions using lasers at 285 and 291 nm. This paper describes the lidar system and analysis technique with some measurement examples. An iterative aerosol correction procedure reduces the retrieval error arising from differential aerosol backscatter in the lower troposphere. Lidar observations with coincident ozonesonde flights demonstrate that the retrieval accuracy ranges from better than 10% below 4 km to better than 20% below 8 km with 750-m vertical resolution and 10-min temporal integration

Measurement of phase function of aerosol at different altitudes by CCD Lidar

NASA Astrophysics Data System (ADS)

Sun, Peiyu; Yuan, Ke'e.; Yang, Jie; Hu, Shunxing

2018-02-01

The aerosols near the ground are closely related to human health and climate change, the study on which has important significance. As we all know, the aerosol is inhomogeneous at different altitudes, of which the phase function is also different. In order to simplify the retrieval algorithm, it is usually assumed that the aerosol is uniform at different altitudes, which will bring measurement error. In this work, an experimental approach is demonstrated to measure the scattering phase function of atmospheric aerosol particles at different heights by CCD lidar system, which could solve the problem of the traditional CCD lidar system in assumption of phase function. The phase functions obtained by the new experimental approach are used to retrieve the aerosol extinction coefficient profiles. By comparison of the aerosol extinction coefficient retrieved by Mie-scattering aerosol lidar and CCD lidar at night, the reliability of new experimental approach is verified.

Lidar Sensors for Autonomous Landing and Hazard Avoidance

NASA Technical Reports Server (NTRS)

Amzajerdian, Farzin; Petway, Larry B.; Hines, Glenn D.; Roback, Vincent E.; Reisse, Robert A.; Pierrottet, Diego F.

2013-01-01

Lidar technology will play an important role in enabling highly ambitious missions being envisioned for exploration of solar system bodies. Currently, NASA is developing a set of advanced lidar sensors, under the Autonomous Landing and Hazard Avoidance (ALHAT) project, aimed at safe landing of robotic and manned vehicles at designated sites with a high degree of precision. These lidar sensors are an Imaging Flash Lidar capable of generating high resolution three-dimensional elevation maps of the terrain, a Doppler Lidar for providing precision vehicle velocity and altitude, and a Laser Altimeter for measuring distance to the ground and ground contours from high altitudes. The capabilities of these lidar sensors have been demonstrated through four helicopter and one fixed-wing aircraft flight test campaigns conducted from 2008 through 2012 during different phases of their development. Recently, prototype versions of these landing lidars have been completed for integration into a rocket-powered terrestrial free-flyer vehicle (Morpheus) being built by NASA Johnson Space Center. Operating in closed-loop with other ALHAT avionics, the viability of the lidars for future landing missions will be demonstrated. This paper describes the ALHAT lidar sensors and assesses their capabilities and impacts on future landing missions.

Comparison of Aerosol Optical Properties and Water Vapor Among Ground and Airborne Lidars and Sun Photometers During TARFOX

NASA Technical Reports Server (NTRS)

Ferrare, R.; Ismail, S.; Browell, E.; Brackett, V.; Clayton, M.; Kooi, S.; Melfi, S. H.; Whiteman, D.; Schwemmer, G.; Evans, K.

2000-01-01

We compare aerosol optical thickness (AOT) and precipitable water vapor (PWV) measurements derived from ground and airborne lidars and sun photometers during the Tropospheric Aerosol Radiative Forcing Observational Experiment. Such comparisons are important to verify the consistency between various remote sensing measurements before employing them in any assessment of the impact of aerosols on the global radiation balance. Total scattering ratio and extinction profiles measured by the ground-based NASA Goddard Space Flight Center scanning Raman lidar system, which operated from Wallops Island, Virginia (37.86 deg N, 75.51 deg W); are compared with those measured by the Lidar Atmospheric Sensing Experiment (LASE) airborne lidar system aboard the NASA ER-2 aircraft. Bias and root-mean-square differences indicate that these measurements generally agreed within about 10%. Aerosol extinction profiles and estimates of AOT are derived from both lidar measurements using a value for the aerosol extinction/backscattering ratio S(sub a) = 60 sr for the aerosol extinction/backscattering ratio, which was determined from the Raman lidar measurements. The lidar measurements of AOT are found to be generally within 25% of the AOT measured by the NASA Ames Airborne Tracking Sun Photometer (AATS-6). However, during certain periods the lidar and Sun photometer measurements of AOT differed significantly, possibly because of variations in the aerosol physical characteristics (e.g., size, composition) which affect S(sub a). Estimates of PWV, derived from water vapor mixing ratio profiles measured by LASE, are within 5-10% of PWV derived from the airborne Sun photometer. Aerosol extinction profiles measured by both lidars show that aerosols were generally concentrated in the lowest 2-3 km.

A study of marine stratocumulus using lidar and other FIRE aircraft observations

NASA Technical Reports Server (NTRS)

Jensen, Jorgen B.; Lenschow, Donald H.

1990-01-01

The National Center for Atmospheric Research (NCAR) airborne infrared lidar system (NAILS) used in the 1987 First ISCCP Regional Experiment (FIRE) off the coast of California is a 10.6 microns wavelength carbon dioxide lidar system constructed by Ron Schwiesow and co-workers at NCAR. The lidar is particularly well suited for detailed observations of cloud shapes; i.e., height of cloud top (when flying above cloud and looking down) and cloud base (when flying below cloud and looking up) along the flight path. A brief summary of the lidar design characteristics is given. The lidar height resolution of plus or minus 3 m allows for the distance between the aircraft and cloud edge to be determined with this accuracy; however, the duration of the emitted pulse is approximately 3 microseconds, which corresponds to a 500 m pulse length. Therefore, variations in backscatter intensities within the clouds can normally not be resolved. Hence the main parameter obtainable from the lidar is distance to cloud; in some cases the cloud depth can also be determined. During FIRE the lidar was operational on 7 of the 10 Electra flights, and data were taken when the distance between cloud and aircraft (minimum range) was at least 500 m. The lidar was usually operated at 8 Hz, which at a flight speed of 100 m s(-1) translates into a horizontal resolution of about 12 m. The backscatter as function of time (equivalent to distance) for each laser pulse is stored in digital form on magnetic tape. Currently, three independent variables are available to the investigators on the FIRE Electra data tapes: lidar range to cloud, strength of return (relative power), and pulse width of return, which is related to penetration depth.

Making lidar more photogenic: creating band combinations from lidar information

USGS Publications Warehouse

Stoker, Jason M.

2010-01-01

Over the past five to ten years the use and applicability of light detection and ranging (lidar) technology has increased dramatically. As a result, an almost exponential amount of lidar data is being collected across the country for a wide range of applications, and it is currently the technology of choice for high resolution terrain model creation, 3-dimensional city and infrastructure modeling, forestry and a wide range of scientific applications (Lin and Mills, 2010). The amount of data that is being delivered across the country is impressive. For example, the U.S. Geological Survey’s (USGS) Center for Lidar Information Coordination and Knowledge (CLICK), which is a National repository of USGS and partner lidar point cloud datasets (Stoker et al., 2006), currently has 3.5 percent of the United States covered by lidar, and has approximately another 5 percent in the processing queue. The majority of data being collected by the commercial sector are from discrete-return systems, which collect billions of lidar points in an average project. There are also a lot of discussions involving a potential National-scale Lidar effort (Stoker et al., 2008).

Assessment and Optimization of Lidar Measurement Availability for Wind Turbine Control: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davoust, S.; Jehu, A.; Bouillet, M.

2014-05-01

Turbine-mounted lidars provide preview measurements of the incoming wind field. By reducing loads on critical components and increasing the potential power extracted from the wind, the performance of wind turbine controllers can be improved [2]. As a result, integrating a light detection and ranging (lidar) system has the potential to lower the cost of wind energy. This paper presents an evaluation of turbine-mounted lidar availability. Availability is a metric which measures the proportion of time the lidar is producing controller-usable data, and is essential when a wind turbine controller relies on a lidar. To accomplish this, researchers from Avent Lidarmore » Technology and the National Renewable Energy Laboratory first assessed and modeled the effect of extreme atmospheric events. This shows how a multirange lidar delivers measurements for a wide variety of conditions. Second, by using a theoretical approach and conducting an analysis of field feedback, we investigated the effects of the lidar setup on the wind turbine. This helps determine the optimal lidar mounting position at the back of the nacelle, and establishes a relationship between availability, turbine rpm, and lidar sampling time. Lastly, we considered the role of the wind field reconstruction strategies and the turbine controller on the definition and performance of a lidar's measurement availability.« less

Use of LOGIC to support lidar operations

NASA Astrophysics Data System (ADS)

Davis-Lunde, Kimberley; Jugan, Laurie A.; Shoemaker, J. Todd

1999-10-01

The Naval Oceanographic Office (NAVOCEANO) and Planning Systems INcorporated are developing the Littoral Optics Geospatial Integrated Capability (LOGIC). LOGIC supports NAVOCEANO's directive to assess the impact of the environment on Fleet systems in areas of operational interest. LOGIC is based in the Geographic Information System (GIS) ARC/INFO and offers a method to view and manipulate optics and ancillary data to support emerging Fleet lidar systems. LOGIC serves as a processing (as required) and quality-checking mechanism for data entering NAVOCEANO's Data Warehouse and handles both remotely sensed and in-water data. LOGIC provides a link between these data and the GIS-based Graphical User Interface, allowing the user to select data manipulation routines and/or system support products. The results of individual modules are displayed via the GIS to provide such products as lidar system performance, laser penetration depth, and asset vulnerability from a lidar threat. LOGIC is being developed for integration into other NAVOCEANO programs, most notably for Comprehensive Environmental Assessment System, an established tool supporting sonar-based systems. The prototype for LOGIC was developed for the Yellow Sea, focusing on a diver visibility support product.

Derivation of Sky-View Factors from LIDAR Data

NASA Technical Reports Server (NTRS)

Kidd, Christopher; Chapman, Lee

2013-01-01

The use of Lidar (Light Detection and Ranging), an active light-emitting instrument, is becoming increasingly common for a range of potential applications. Its ability to provide fine resolution spatial and vertical resolution elevation data makes it ideal for a wide range of studies. This paper demonstrates the capability of Lidar data to measure sky view factors (SVF). The Lidar data is used to generate a spatial map of SVFs which are then compared against photographically-derived SVF at selected point locations. At each location three near-surface elevations measurements were taken and compared with collocated Lidar-derived estimated. It was found that there was generally good agreement between the two methodologies, although with decreasing SVF the Lidar-derived technique tended to overestimate the SVF: this can be attributed in part to the spatial resolution of the Lidar sampling. Nevertheless, airborne Lidar systems can map sky view factors over a large area easily, improving the utility of such data in atmospheric and meteorological models.

Performance modeling of ultraviolet Raman lidar systems for daytime profiling of atmospheric water vapor

NASA Technical Reports Server (NTRS)

Ferrare, R. A.; Whiteman, D. N.; Melfi, S. H.; Goldsmith, J. E. M.; Bisson, S. E.; Lapp, M.

1991-01-01

We describe preliminary results from a comprehensive computer model developed to guide optimization of a Raman lidar system for measuring daytime profiles of atmospheric water vapor, emphasizing an ultraviolet, solar-blind approach.

Cloud occurrences and cloud radiative effects (CREs) from CERES-CALIPSO-CloudSat-MODIS (CCCM) and CloudSat radar-lidar (RL) products

NASA Astrophysics Data System (ADS)

Ham, Seung-Hee; Kato, Seiji; Rose, Fred G.; Winker, David; L'Ecuyer, Tristan; Mace, Gerald G.; Painemal, David; Sun-Mack, Sunny; Chen, Yan; Miller, Walter F.

2017-08-01

Two kinds of cloud products obtained from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), CloudSat, and Moderate Resolution Imaging Spectroradiometer (MODIS) are compared and analyzed in this study: Clouds and the Earth's Radiant Energy System (CERES)-CALIPSO-CloudSat-MODIS (CCCM) product and CloudSat radar-lidar products such as GEOPROF-LIDAR and FLXHR-LIDAR. Compared to GEOPROF-LIDAR, low-level (<1 km) cloud occurrences in CCCM are larger over tropical oceans because the CCCM algorithm uses a more relaxed threshold of cloud-aerosol discrimination score for CALIPSO Vertical Feature Mask product. In contrast, midlevel (1-8 km) cloud occurrences in GEOPROF-LIDAR are larger than CCCM at high latitudes (>40°). The difference occurs when hydrometeors are detected by CALIPSO lidar but are undetected by CloudSat radar. In the comparison of cloud radiative effects (CREs), global mean differences between CCCM and FLXHR-LIDAR are mostly smaller than 5 W m-2, while noticeable regional differences are found. For example, CCCM shortwave (SW) and longwave (LW) CREs are larger than FXLHR-LIDAR along the west coasts of Africa and America because the GEOPROF-LIDAR algorithm misses shallow marine boundary layer clouds. In addition, FLXHR-LIDAR SW CREs are larger than the CCCM counterpart over tropical oceans away from the west coasts of America. Over midlatitude storm-track regions, CCCM SW and LW CREs are larger than the FLXHR-LIDAR counterpart.

Imaging Flash Lidar for Safe Landing on Solar System Bodies and Spacecraft Rendezvous and Docking

NASA Technical Reports Server (NTRS)

Amzajerdian, Farzin; Roback, Vincent E.; Bulyshev, Alexander E.; Brewster, Paul F.; Carrion, William A; Pierrottet, Diego F.; Hines, Glenn D.; Petway, Larry B.; Barnes, Bruce W.; Noe, Anna M.

2015-01-01

NASA has been pursuing flash lidar technology for autonomous, safe landing on solar system bodies and for automated rendezvous and docking. During the final stages of the landing from about 1 kilometer to 500 meters above the ground, the flash lidar can generate 3-Dimensional images of the terrain to identify hazardous features such as craters, rocks, and steep slopes. The onboard flight computer can then use the 3-D map of terrain to guide the vehicle to a safe location. As an automated rendezvous and docking sensor, the flash lidar can provide relative range, velocity, and bearing from an approaching spacecraft to another spacecraft or a space station. NASA Langley Research Center has developed and demonstrated a flash lidar sensor system capable of generating 16,000 pixels range images with 7 centimeters precision, at 20 Hertz frame rate, from a maximum slant range of 1800 m from the target area. This paper describes the lidar instrument and presents the results of recent flight tests onboard a rocket-propelled free-flyer vehicle (Morpheus) built by NASA Johnson Space Center. The flights were conducted at a simulated lunar terrain site, consisting of realistic hazard features and designated landing areas, built at NASA Kennedy Space Center specifically for this demonstration test. This paper also provides an overview of the plan for continued advancement of the flash lidar technology aimed at enhancing its performance to meet both landing and automated rendezvous and docking applications.

Spatiotemporal Variability in Observations of Urban Mixed-Layer Heights from Surface-based Lidar Systems during DISCOVER-AQ 2011

NASA Astrophysics Data System (ADS)

Lewis, J. R.; Banks, R. F.; Berkoff, T.; Welton, E. J.; Joseph, E.; Thompson, A. M.; Decola, P.; Hegarty, J. D.

2015-12-01

Accurate characterization of the planetary boundary layer height is crucial for numerical weather prediction, estimating pollution emissions and modeling air quality. More so, given the increasing trend in global urban populations, there is a growing need to improve our understanding of the urban boundary layer structure and development. The Deriving Information on Surface conditions from COlumn and VERtically resolved observations relevant to Air Quality (DISCOVER-AQ) 2011 field campaign, which took place in the Baltimore-Washington DC region, offered a unique opportunity to study boundary layer processes in an urban area using a geographically dense collection of surface-based lidar systems (see figure). Lidars use aerosols as tracers for atmospheric boundary layer dynamics with high vertical and temporal resolutions. In this study, we use data from two permanent Micropulse Lidar Network (MPLNET) sites and five field deployed Micropulse lidar (MPL) systems in order to observe spatiotemporal variations in the daytime mixed layer height. We present and compare lidar-derived retrievals of the mixed layer height using two different methods. The first method uses the wavelet covariance transform and a "fuzzy logic" attribution scheme in order to determine the mixed layer height. The second method uses an objective approach utilizing a time-adaptive extended Kalman filter. Independent measurements of the boundary layer height are obtained using profiles from ozonesonde launches at the Beltsville and Edgewood sites for comparison with lidar observations.

Integrated remote sensing and visualization (IRSV) system for transportation infrastructure operations and management, phase two, volume 3 : advanced consideration in LiDAR technology for bridge evaluation.

DOT National Transportation Integrated Search

2012-03-01

This report describes Phase Two enhancement of terrestrial LiDAR scanning for bridge damage : evaluation that was initially developed in Phase One. Considering the spatial and reflectivity : information contained in LiDAR scans, two detection algorit...

Design of an ultraviolet fluorescence lidar for biological aerosol detection

NASA Astrophysics Data System (ADS)

Rao, Zhimin; Hua, Dengxin; He, Tingyao; Le, Jing

2016-09-01

In order to investigate the biological aerosols in the atmosphere, we have designed an ultraviolet laser induced fluorescence lidar based on the lidar measuring principle. The fluorescence lidar employs a Nd:YAG laser of 266 nm as an excited transmitter, and examines the intensity of the received light at 400 nm for biological aerosol concentration measurements. In this work, we firstly describe the designed configuration and the simulation to estimate the measure range and the system resolution of biological aerosol concentration under certain background radiation. With a relative error of less than 10%, numerical simulations show the system is able to monitor biological aerosols within detected distances of 1.8 km and of 7.3 km in the daytime and nighttime, respectively. Simulated results demonstrate the designed fluorescence lidar is capable to identify a minimum concentration of biological aerosols at 5.0×10-5 ppb in the daytime and 1.0×10-7 ppb in the nighttime at the range of 0.1 km. We believe the ultraviolet laser induced fluorescence lidar can be spread in the field of remote sensing of biological aerosols in the atmosphere.

Characterization of turbulent wake of wind turbine by coherent Doppler lidar

NASA Astrophysics Data System (ADS)

Wu, Songhua; Yin, Jiaping; Liu, Bingyi; Liu, Jintao; Li, Rongzhong; Wang, Xitao; Feng, Changzhong; Zhuang, Quanfeng; Zhang, Kailin

2014-11-01

The indispensable access to real turbulent wake behavior is provided by the pulsed coherent Doppler Light Detection and Ranging (LIDAR) which operates by transmitting a laser beam and detecting the radiation backscattered by atmospheric aerosol particles. The Doppler shift in the frequency of the backscattered signal is analyzed to obtain the line-of-sight (LOS) velocity component of the air motion. From the LOS velocities the characteristic of the turbulent wake can be deduced. The Coherent Doppler LIDAR (CDL) is based on all-fiber laser technology and fast digital-signal-processing technology. The 1.5 µm eye-safe Doppler LIDAR system has a pulse length of 200ns and a pulse repetition frequency of 10 kHz. The speed measurement range is ±50m/s and the speed measurement uncertainty is 0.3 m/s. The 2-axis beam scanner and detection range of 3000m enable the system to monitor the whole wind farming filed. Because of the all-fiber structure adoption, the system is stable, reliable and high-integrated. The wake vortices of wind turbine blades with different spatial and temporal scales have been observed by LIDAR. In this paper, the authors discuss the possibility of using LIDAR measurements to characterize the complicated wind field, specifically wind velocity deficit and terrain effects.

Windshear detection and avoidance - Airborne systems perspective

NASA Technical Reports Server (NTRS)

Bowles, Roland L.; Targ, Russell

1988-01-01

The generalized windshear hazard index presently defined is derived from aircraft-position wind data and remotely sensed data obtained along the extended flight path by such candidate sensor technologies as microwave Doppler radar, Doppler lidar, and IR radiometry. Attention is given here to the results of a comparative evaluation of CO2 and Ho:YAG lidar sensor-employing windshear-detection systems, over a range 1-3 km ahead of the aircraft (corresponding to 15-45 sec of warning time). While the technology for a 10.6-micron CO2 lidar system is available, an optimum 2-micron REE laser crystal-based system remains to be developed.

A Backscatter-Lidar Forward-Operator

NASA Astrophysics Data System (ADS)

Geisinger, Armin; Behrendt, Andreas; Wulfmeyer, Volker; Vogel, Bernhard; Mattis, Ina; Flentje, Harald; Förstner, Jochen; Potthast, Roland

2015-04-01

We have developed a forward-operator which is capable of calculating virtual lidar profiles from atmospheric state simulations. The operator allows us to compare lidar measurements and model simulations based on the same measurement parameter: the lidar backscatter profile. This method simplifies qualitative comparisons and also makes quantitative comparisons possible, including statistical error quantification. Implemented into an aerosol-capable model system, the operator will act as a component to assimilate backscatter-lidar measurements. As many weather services maintain already networks of backscatter-lidars, such data are acquired already in an operational manner. To estimate and quantify errors due to missing or uncertain aerosol information, we started sensitivity studies about several scattering parameters such as the aerosol size and both the real and imaginary part of the complex index of refraction. Furthermore, quantitative and statistical comparisons between measurements and virtual measurements are shown in this study, i.e. applying the backscatter-lidar forward-operator on model output.

Raman LIDAR for UHECR experiments: an overview of the L'Aquila (Italy) lidar station experience for the retrieval of quality-assured data

NASA Astrophysics Data System (ADS)

Iarlori, Marco; Rizi, Vincenzo; D'Amico, Giuseppe; Freudenthaler, Volker; Wandinger, Ulla; Grillo, Aurelio

L'Aquila (Italy) lidar station is part of the EARLINET (European Aerosol Research Lidar Network) since its beginning in the 2000. In the EARLINET community great efforts are devoted to the quality-assurance of the aerosol optical properties inserted in the database. To this end, each lidar station performed intercomparisons with reference instruments, a series of internal hardware checks in order to assess the quality of their instruments and exercises to test the algorithms used to retrieve the aerosol optical parameters. In this paper we give an overview of our experience within EARLINET qualityassurance (QA) program, which was adopted for the Raman lidar (RL) operated in the AUGER Observatory. This program could be systematically adopted for the lidar systems needed for the current and upcoming UHECR experiments, like CTA (Cherenkov Telescope Array).

Relativity effects for space-based coherent lidar experiments

NASA Technical Reports Server (NTRS)

Gudimetla, V. S. Rao

1996-01-01

An effort was initiated last year in the Astrionics Laboratory at Marshall Space Flight Center to examine and incorporate, if necessary, the effects of relativity in the design of space-based lidar systems. A space-based lidar system, named AEOLUS, is under development at Marshall Space Flight Center and it will be used to accurately measure atmospheric wind profiles. Effects of relativity were also observed in the performance of space-based systems, for example in case of global positioning systems, and corrections were incorporated into the design of instruments. During the last summer, the effects of special relativity on the design of space-based lidar systems were studied in detail, by analyzing the problem of laser scattering off a fixed target when the source and a co-located receiver are moving on a spacecraft. Since the proposed lidar system uses a coherent detection system, errors even in the order of a few microradians must be corrected to achieve a good signal-to-noise ratio. Previous analysis assumed that the ground is flat and the spacecraft is moving parallel to the ground, and developed analytical expressions for the location, direction and Doppler shift of the returning radiation. Because of the assumptions used in that analysis, only special relativity effects were involved. In this report, that analysis is extended to include general relativity and calculate its effects on the design.

Aerosol Retrievals from Proposed Satellite Bistatic Lidar Observations: Algorithm and Information Content

NASA Astrophysics Data System (ADS)

Alexandrov, M. D.; Mishchenko, M. I.

2017-12-01

Accurate aerosol retrievals from space remain quite challenging and typically involve solving a severely ill-posed inverse scattering problem. We suggested to address this ill-posedness by flying a bistatic lidar system. Such a system would consist of formation flying constellation of a primary satellite equipped with a conventional monostatic (backscattering) lidar and an additional platform hosting a receiver of the scattered laser light. If successfully implemented, this concept would combine the measurement capabilities of a passive multi-angle multi-spectral polarimeter with the vertical profiling capability of a lidar. Thus, bistatic lidar observations will be free of deficiencies affecting both monostatic lidar measurements (caused by the highly limited information content) and passive photopolarimetric measurements (caused by vertical integration and surface reflection).We present a preliminary aerosol retrieval algorithm for a bistatic lidar system consisting of a high spectral resolution lidar (HSRL) and an additional receiver flown in formation with it at a scattering angle of 165 degrees. This algorithm was applied to synthetic data generated using Mie-theory computations. The model/retrieval parameters in our tests were the effective radius and variance of the aerosol size distribution, complex refractive index of the particles, and their number concentration. Both mono- and bimodal aerosol mixtures were considered. Our algorithm allowed for definitive evaluation of error propagation from measurements to retrievals using a Monte Carlo technique, which involves random distortion of the observations and statistical characterization of the resulting retrieval errors. Our tests demonstrated that supplementing a conventional monostatic HSRL with an additional receiver dramatically increases the information content of the measurements and allows for a sufficiently accurate characterization of tropospheric aerosols.

Calibration of a Direct Detection Doppler Wind Lidar System using a Wind Tunnel

NASA Astrophysics Data System (ADS)

Rees, David

2012-07-01

As a critical stage of a Project to develop an airborne Direct-Detection Doppler Wind Lidar System, it was possible to exploit a Wind Tunnel of the VZLU, Prague, Czech Republic for a comprehensive series of tests against calibrated Air Speed generated by the Wind Tunnel. The initial results from these test sequences will be presented. The rms wind speed errors were of order 0.25 m/sec - very satisfactory for this class of Doppler Wind Lidar measurements. The next stage of this Project will exploit a more highly-developed laser and detection system for measurements of wind shear, wake vortex and other potentially hazardous meteorological phenomena at Airports. Following the end of this Project, key parts of the instrumentation will be used for routine ground-based Doppler Wind Lidar measurements of the troposphere and stratosphere.

INS/GPS/LiDAR Integrated Navigation System for Urban and Indoor Environments Using Hybrid Scan Matching Algorithm

PubMed Central

Gao, Yanbin; Liu, Shifei; Atia, Mohamed M.; Noureldin, Aboelmagd

2015-01-01

This paper takes advantage of the complementary characteristics of Global Positioning System (GPS) and Light Detection and Ranging (LiDAR) to provide periodic corrections to Inertial Navigation System (INS) alternatively in different environmental conditions. In open sky, where GPS signals are available and LiDAR measurements are sparse, GPS is integrated with INS. Meanwhile, in confined outdoor environments and indoors, where GPS is unreliable or unavailable and LiDAR measurements are rich, LiDAR replaces GPS to integrate with INS. This paper also proposes an innovative hybrid scan matching algorithm that combines the feature-based scan matching method and Iterative Closest Point (ICP) based scan matching method. The algorithm can work and transit between two modes depending on the number of matched line features over two scans, thus achieving efficiency and robustness concurrently. Two integration schemes of INS and LiDAR with hybrid scan matching algorithm are implemented and compared. Real experiments are performed on an Unmanned Ground Vehicle (UGV) for both outdoor and indoor environments. Experimental results show that the multi-sensor integrated system can remain sub-meter navigation accuracy during the whole trajectory. PMID:26389906

INS/GPS/LiDAR Integrated Navigation System for Urban and Indoor Environments Using Hybrid Scan Matching Algorithm.

PubMed

Gao, Yanbin; Liu, Shifei; Atia, Mohamed M; Noureldin, Aboelmagd

2015-09-15

This paper takes advantage of the complementary characteristics of Global Positioning System (GPS) and Light Detection and Ranging (LiDAR) to provide periodic corrections to Inertial Navigation System (INS) alternatively in different environmental conditions. In open sky, where GPS signals are available and LiDAR measurements are sparse, GPS is integrated with INS. Meanwhile, in confined outdoor environments and indoors, where GPS is unreliable or unavailable and LiDAR measurements are rich, LiDAR replaces GPS to integrate with INS. This paper also proposes an innovative hybrid scan matching algorithm that combines the feature-based scan matching method and Iterative Closest Point (ICP) based scan matching method. The algorithm can work and transit between two modes depending on the number of matched line features over two scans, thus achieving efficiency and robustness concurrently. Two integration schemes of INS and LiDAR with hybrid scan matching algorithm are implemented and compared. Real experiments are performed on an Unmanned Ground Vehicle (UGV) for both outdoor and indoor environments. Experimental results show that the multi-sensor integrated system can remain sub-meter navigation accuracy during the whole trajectory.

ATM Coastal Topography-Alabama 2001

USGS Publications Warehouse

Nayegandhi, Amar; Yates, Xan; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Klipp, Emily S.; Wright, C. Wayne

2009-01-01

These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Alabama coastline, acquired October 3-4, 2001. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative scanning Lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning Lidar system that measures high-resolution topography of the land surface, and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for pre-survey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography.

ATM Coastal Topography-Florida 2001: Eastern Panhandle

USGS Publications Warehouse

Yates, Xan; Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Klipp, Emily S.; Wright, C. Wayne

2009-01-01

These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the eastern Florida panhandle coastline, acquired October 2, 2001. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative scanning Lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning Lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography.

Evaluation of Terrestrial LIDAR for Monitoring Geomorphic Change at Archeological Sites in Grand Canyon National Park, Arizona

USGS Publications Warehouse

Collins, Brian D.; Brown, Kristin M.; Fairley, Helen C.

2008-01-01

This report presents the results of an evaluation of terrestrial light detection and ranging (LIDAR) for monitoring geomorphic change at archeological sites located within Grand Canyon National Park, Ariz. Traditionally, topographic change-detection studies have used total station methods for the collection of data related to key measurable features of site erosion such as the location of thalwegs and knickpoints of gullies that traverse archeological sites (for example, Pederson and others, 2003). Total station methods require survey teams to walk within and on the features of interest within the archeological sites to take accurate measurements. As a result, site impacts may develop such as trailing, damage to cryptogamic crusts, and surface compaction that can exacerbate future erosion of the sites. National Park Service (NPS) resource managers have become increasingly concerned that repeated surveys for research and monitoring purposes may have a detrimental impact on the resources that researchers are trying to study and protect. Beginning in 2006, the Sociocultural Program of the U.S. Geological Survey's (USGS) Grand Canyon Monitoring and Research Center (GCMRC) initiated an evaluation of terrestrial LIDAR as a new monitoring tool that might enhance data quality and reduce site impacts. This evaluation was conducted as one part of an ongoing study to develop objective, replicable, quantifiable monitoring protocols for tracking the status and trend of variables affecting archeological site condition along the Colorado River corridor. The overall study consists of two elements: (1) an evaluation of the methodology through direct comparison to geomorphologic metrics already being collected by total station methods (this report) and (2) an evaluation of terrestrial LIDAR's ability to detect topographic change through the collection of temporally different datasets (a report on this portion of the study is anticipated early in 2009). The main goals of the first element of study were to 1. test the methodology and survey protocols of terrestrial LIDAR surveying under actual archeological site field conditions, 2. examine the ability to collect topographic data of entire archeological sites given such constraints as vegetation and rough topography, and 3. evaluate the ability of terrestrial LIDAR to accurately map the locations of key geomorphic features already being collected by total station methods such as gully thalweg and knickpoint locations. This report focuses on the ability of terrestrial LIDAR to duplicate total station methods, including typical erosion-related change features such as the plan view gully thalweg location and the gully thalweg long profile. The report also presents information concerning the use of terrestrial LIDAR for archeological site monitoring in a general sense. In addition, a detailed comparison of the site impacts caused by both total station and terrestrial LIDAR survey methods is presented using a suite of indicators, including total field survey time, field footstep count, and data-processing time. A thorough discussion of the relative benefits and limitations of using terrestrial LIDAR for monitoring erosion-induced changes at archeological sites in Grand Canyon National Park concludes this report.

Continuous Lidar Monitoring of Polar Stratospheric Clouds at the South Pole

NASA Technical Reports Server (NTRS)

Campbell, James R.; Welton, Ellsworth J.; Spinhirne, James D

2009-01-01

Polar stratospheric clouds (PSC) play a primary role in the formation of annual ozone holes over Antarctica during the austral sunrise. Meridional temperature gradients in the lower stratosphere and upper troposphere, caused by strong radiative cooling, induce a broad dynamic vortex centered near the South Pole that decouples and insulates the winter polar airmass. PSC nucleate and grow as vortex temperatures gradually fall below equilibrium saturation and frost points for ambient sulfate, nitrate, and water vapor concentrations (generally below 197 K). Cloud surfaces promote heterogeneous reactions that convert stable chlorine and bromine-based molecules into photochemically active ones. As spring nears, and the sun reappears and rises, photolysis decomposes these partitioned compounds into individual halogen atoms that react with and catalytically destroy thousands of ozone molecules before they are stochastically neutralized. Despite a generic understanding of the ozone hole paradigm, many key components of the system, such as cloud occurrence, phase, and composition; particle growth mechanisms; and denitrification of the lower stratosphere have yet to be fully resolved. Satellite-based observations have dramatically improved the ability to detect PSC and quantify seasonal polar chemical partitioning. However, coverage directly over the Antarctic plateau is limited by polar-orbiting tracks that rarely exceed 80 degrees S. In December 1999, a NASA Micropulse Lidar Network instrument (MPLNET) was first deployed to the NOAA Earth Systems Research Laboratory (ESRL) Atmospheric Research Observatory at the Amundsen-Scott South Pole Station for continuous cloud and aerosol profiling. MPLNET instruments are eye-safe, capable of full-time autonomous operation, and suitably rugged and compact to withstand long-term remote deployment. With only brief interruptions during the winters of 2001 and 2002, a nearly continuous data archive exists to the present.

Boundary layer temperature measurements of a noctual urban boundary layer

NASA Astrophysics Data System (ADS)

Holloway, Simon; Ricketts, Hugo; Vaughan, Geraint

2018-04-01

A low-power lidar system based in Manchester, United Kingdom has been developed to measure temperature profiles in the nocturnal urban boundary layer. The lidar transmitter uses a 355nm diode-pumped solid state Nd:YAG laser and two narrow-band interference filters in the receiver filter out rotational Raman lines that are dependent on temperature. The spectral response of the lidar is calibrated using a monochromator. Temperature profiles measured by the system are calibrated by comparison to co-located radiosondes.

Lidar for Wind and Optical Turbulence Profiling

NASA Astrophysics Data System (ADS)

Fastig, Shlomo; Porat, Omer; Englander, Abraham; Sprung, Detlev; Stein, Karin U.; Sucher, Erik

2018-04-01

A field campaign for the comparison investigation of systems to measure wind and optical turbulence profiles was conducted in northern Germany. The experimental effort was to compare the performance of the LIDAR, SODAR-RASS and ultrasonic anemometers for the measurement of the above mentioned atmospheric parameters. Soreq's LIDAR is a fiber laser based system demonstrator for the vertical profiling of the wind and turbulence, based on the correlation of aerosol density variations. It provides measurements up to 350m with 20m resolution.

Effects of multiple scattering on time- and depth-resolved signals in airborne lidar systems

NASA Technical Reports Server (NTRS)

Punjabi, A.; Venable, D. D.

1986-01-01

A semianalytic Monte Carlo radiative transfer model (SALMON) is employed to probe the effects of multiple-scattering events on the time- and depth-resolved lidar signals from homogeneous aqueous media. The effective total attenuation coefficients in the single-scattering approximation are determined as functions of dimensionless parameters characterizing the lidar system and the medium. Results show that single-scattering events dominate when these parameters are close to their lower bounds and that when their values exceed unity multiple-scattering events dominate.

Correction Technique for Raman Water Vapor Lidar Signal-Dependent Bias and Suitability for Water Wapor Trend Monitoring in the Upper Troposphere

NASA Technical Reports Server (NTRS)

Whiteman, D. N.; Cadirola, M.; Venable, D.; Calhoun, M.; Miloshevich, L; Vermeesch, K.; Twigg, L.; Dirisu, A.; Hurst, D.; Hall, E.;

Real-time full-motion color Flash lidar for target detection and identification

NASA Astrophysics Data System (ADS)

Nelson, Roy; Coppock, Eric; Craig, Rex; Craner, Jeremy; Nicks, Dennis; von Niederhausern, Kurt

2015-05-01

Greatly improved understanding of areas and objects of interest can be gained when real time, full-motion Flash LiDAR is fused with inertial navigation data and multi-spectral context imagery. On its own, full-motion Flash LiDAR provides the opportunity to exploit the z dimension for improved intelligence vs. 2-D full-motion video (FMV). The intelligence value of this data is enhanced when it is combined with inertial navigation data to produce an extended, georegistered data set suitable for a variety of analysis. Further, when fused with multispectral context imagery the typical point cloud now becomes a rich 3-D scene which is intuitively obvious to the user and allows rapid cognitive analysis with little or no training. Ball Aerospace has developed and demonstrated a real-time, full-motion LIDAR system that fuses context imagery (VIS to MWIR demonstrated) and inertial navigation data in real time, and can stream these information-rich geolocated/fused 3-D scenes from an airborne platform. In addition, since the higher-resolution context camera is boresighted and frame synchronized to the LiDAR camera and the LiDAR camera is an array sensor, techniques have been developed to rapidly interpolate the LIDAR pixel values creating a point cloud that has the same resolution as the context camera, effectively creating a high definition (HD) LiDAR image. This paper presents a design overview of the Ball TotalSight™ LIDAR system along with typical results over urban and rural areas collected from both rotary and fixed-wing aircraft. We conclude with a discussion of future work.

High Pulse Repetition Rate, Eye Safe, Visible Wavelength Lidar Systems: Design, Results and Potential

NASA Technical Reports Server (NTRS)

Spinhirne, James; Berkoff, Timothy; Welton, Elsworth; Campbell, James; OCStarr, David (Technical Monitor)

2002-01-01

In 1993 the first of the eye safe visible wavelength lidar systems known now as Micro Pulse Lidar (MPL) became operational. Since that time there have been several dozen of these systems produced and applied for full time profiling of atmospheric cloud and aerosol structure. There is currently an observational network of MPL sites to support global climate research. In the course of application of these instruments there have been significant improvements in understanding, design and performance of the systems. There are addition potential and applications beyond current practice for the high repetition rate, eye safe designs. The MPL network and the current capability, design and future potential of MPL systems are described.

LASA (Lidar Atmospheric Sounder and Altimeter) Earth Observing System. Volume 2D: Instrument Panel Report

NASA Technical Reports Server (NTRS)

1987-01-01

The Earth Observing System (Eos) will provide an ideal forum in which the stronly synergistic characteristics of the lidar systems can be used in concert with the characteristics of a number of other sensors to better understand the Earth as a system. Progress in the development of more efficient and long-lasting laser systems will insure their availability in the Eos time frame. The necessary remote-sensing techniques are being developed to convert the Lidar Atmospheric Sounder and Altimeter (LASA) observations into the proper scientific parameters. Each of these activities reinforces the promise that LASA and GLRS will be a reality in the Eos era.

Lidar-based Research and Innovation at DTU Wind Energy - a Review

NASA Astrophysics Data System (ADS)

Mikkelsen, T.

2014-06-01

As wind turbines during the past decade have increased in size so have the challenges met by the atmospheric boundary-layer meteorologists and the wind energy society to measure and characterize the huge-volume wind fields surpassing and driving them. At the DTU Wind Energy test site "Østerild" for huge wind turbines, the hub-height of a recently installed 8 MW Vestas V164 turbine soars 143 meters up above the ground, and its rotor of amazing 164 meters in diameter make the turbine tips flicker 225 meters into the sky. Following the revolution in photonics-based telecommunication at the turn of the Millennium new fibre-based wind lidar technologies emerged and DTU Wind Energy, at that time embedded within Rise National Laboratory, began in collaboration with researchers from wind lidar companies to measure remote sensed wind profiles and turbulence structures within the atmospheric boundary layer with the emerging, at that time new, all-fibre-based 1.55 μ coherent detection wind lidars. Today, ten years later, DTU Wind Energy routinely deploys ground-based vertical profilers instead of met masts for high-precision measurements of mean wind profiles and turbulence profiles. At the departments test site "Høvsøre" DTU Wind Energy also routinely calibrate and accredit wind lidar manufactures wind lidars. Meanwhile however, new methodologies for power curve assessment based on ground-based and nacelle based lidars have also emerged. For improving the turbines power curve assessments and for advancing their control with feed-forward wind measurements experience has also been gained with wind lidars installed on turbine nacelles and integrated into the turbines rotating spinners. A new mobile research infrastructure WindScanner.dk has also emerged at DTU Wind Energy. Wind and turbulence fields are today scanned from sets of three simultaneously in space and time synchronized scanning lidars. One set consists of three fast scanning continuous-wave based wind lidars (short-range system), and another consisting of three synchronized pulsed wind lidar systems (long-range system). Today, wind lidar profilers and WindScanners are routinely deployed and operated during field tests and measurement campaigns. Lidars have been installed and operated from ground, on offshore platforms, and also as scanning lidars integrated in operating turbines. As a result, wind profiles and also detailed 3D scanning of wind and turbulence fields have been achieved: 1) of the free wind aloft, 2) over complex terrain, 3) at coastal ranges with land-sea interfaces, 4) offshore, 5) in turbine inflow induction zone, and 6) of the complex and turbulent flow fields in the wakes inside wind parks.

Performance of Charm-F - the airborne demonstrator for Merlin

NASA Astrophysics Data System (ADS)

Amediek, Axel; Ehret, Gerhard; Fix, Andreas; Wirth, Martin; Büdenbender, Christian; Quatrevalet, Mathieu; Kiemle, Christoph

2018-04-01

In 2015, the new airborne lidar CHARM-F for the measurement of the greenhouse gases carbon dioxide and methane was set into operation. It is an integrated path differential absorption (IPDA) lidar designed for the use onboard the German research aircraft HALO. Due to its high technological similarity to the MERLIN space lidar, it is also a demonstrator for the space system. Here, we report on CHARM-F's technology, the experiences with the IPDA lidar method and the achieved performance.

Multiangle lidar observations of the Atmosphere

NASA Astrophysics Data System (ADS)

Lalitkumar Prakash, Pawar; Choukiker, Yogesh Kumar; Raghunath, K.

2018-04-01

Atmospheric Lidars are used extensively to get aerosol parameters like backscatter coefficient, backscatter ratio etc. National Atmospheric Research Laboratory, Gadanki (13°N, 79°E), India has a powerful lidar which has alt-azimuth capability. Inversion method is applied to data from observations of lidar system at different azimuth and elevation angles. Data Analysis is described and Observations in 2D and 3D format are discussed. Presence of Cloud and the variation of backscatter parameters are seen in an interesting manner.

A new method to derive middle atmospheric temperature profiles using a combination of Rayleigh lidar and O2 airglow temperatures measurements

NASA Astrophysics Data System (ADS)

Taori, A.; Jayaraman, A.; Raghunath, K.; Kamalakar, V.

2012-01-01

The vertical temperature profiles in a typical Rayleigh lidar system depends on the backscatter photon counts and the CIRA-86 model inputs. For the first time, we show that, by making simultaneous measurements of Rayleigh lidar and upper mesospheric O2 temperatures, the lidar capability can be enhanced to obtain mesospheric temperature profile up to about 95 km altitudes. The obtained results are compared with instantaneous space-borne SABER measurements for a validation.

Improving LiDAR Data Post-Processing Techniques for Archaeological Site Management and Analysis: A Case Study from Canaveral National Seashore Park

NASA Astrophysics Data System (ADS)

Griesbach, Christopher

Methods used to process raw Light Detection and Ranging (LiDAR) data can sometimes obscure the digital signatures indicative of an archaeological site. This thesis explains the negative effects that certain LiDAR data processing procedures can have on the preservation of an archaeological site. This thesis also presents methods for effectively integrating LiDAR with other forms of mapping data in a Geographic Information Systems (GIS) environment in order to improve LiDAR archaeological signatures by examining several pre-Columbian Native American shell middens located in Canaveral National Seashore Park (CANA).

Overview of Lidar Contributions to the Atmospheric Carbon and Transport - America (ACT-America) Program

NASA Astrophysics Data System (ADS)

Davis, K. J.; Meadows, B.; Barrick, J. D. W.; Bell, E.; Browell, E. V.; Campbell, J. F.; DiGangi, J. P.; Chen, G.; Dobler, J. T.; Fan, T. F.; Feng, S.; Fried, A.; Kooi, S. A.; Lauvaux, T.; Lin, B.; McGill, M. J.; Miles, N.; Nehrir, A. R.; Obland, M. D.; O'Dell, C.; Pal, S.; Pauly, R.; Sweeney, C.; Yang, M. Y.

2017-12-01

The Atmospheric Carbon and Transport - America (ACT-America) is an Earth Venture Suborbital -2 (EVS-2) mission sponsored by the Earth Science Division of NASA's Science Mission Directorate. A major objective is to enhance our knowledge of the sources/sinks and transport of atmospheric CO2 through the application of remote and in situ airborne measurements of CO2 and other atmospheric properties on spatial and temporal scales not previously available to the science community. ACT-America consists of five campaigns to measure regional carbon and evaluate transport under various meteorological conditions in three regional areas of the Continental United States. Three of the five campaigns, summer 2016, winter 2017, and fall 2017, have taken place. Data have been collected during these campaigns using 2 airborne platforms (NASA Wallops' C-130 and NASA Langley's B-200) with in-situ instruments on both aircraft and three lidar systems on the C-130, along with instrumented towers and coordinated under flights with the Orbiting Carbon Observatory (OCO-2) satellite. The lidar systems include the Harris Corp. Multi-Frequency Fiber Laser Lidar (MFLL), the NASA Langley ASCENDS CarbonHawk Experiment Simulator (ACES) and the Goddard Cloud Physics Laboratory (CPL). The airborne lidars provide unique data that complement the more traditional in situ sensors. Lidar CO2 measurements provide integrated views of spatial variations of partial columns of atmospheric CO2 which can be adjusted to the column of scientific interest by changing flight altitudes. Lidar backscatter data provide detailed views of atmospheric layers, including the atmospheric boundary layer, residual layers, and cloud layers. The combination of these two lidars provide a far more comprehensive view of atmospheric structure and CO2 content than can be achieved with in situ measurements alone. This presentation provides an overview of the application of these three lidar systems toward achieving ACT-America's scientific objectives.

CLASS: Coherent Lidar Airborne Shear Sensor. Windshear avoidance

NASA Technical Reports Server (NTRS)

Targ, Russell

1991-01-01

The coherent lidar airborne shear sensor (CLASS) is an airborne CO2 lidar system being designed and developed by Lockheed Missiles and Space Company, Inc. (LMSC) under contract to NASA Langley Research Center. The goal of this program is to develop a system with a 2- to 4-kilometer range that will provide a warning time of 20 to 40 seconds, so that the pilot can avoid the hazards of low-altitude wind shear under all weather conditions. It is a predictive system which will warn the pilot about a hazard that the aircraft will experience at some later time. The ability of the system to provide predictive warnings of clear air turbulence will also be evaluated. A one-year flight evaluation program will measure the line-of-sight wind velocity from a wide variety of wind fields obtained by an airborne radar, an accelerometer-based reactive wind-sensing system, and a ground-based Doppler radar. The success of the airborne lidar system will be determined by its correlation with the windfield as indicated by the onboard reactive system, which indicates the winds actually experienced by the NASA Boeing 737 aircraft.

Speckle noise in satellite based lidar systems

NASA Technical Reports Server (NTRS)

Gardner, C. S.

1977-01-01

The lidar system model was described, and the statistics of the signal and noise at the receiver output were derived. Scattering media effects were discussed along with polarization and atmospheric turbulence. The major equations were summarized and evaluated for some typical parameters.

Pointing Knowledge for SPARCLE and Space-Based Doppler Wind Lidars in General

NASA Technical Reports Server (NTRS)

Emmitt, G. D.; Miller, T.; Spiers, G.

1999-01-01

The SPAce Readiness Coherent Lidar Experiment (SPARCLE) will fly on a space shuttle to demonstrate the use of a coherent Doppler wind lidar to accurately measure global tropospheric winds. To achieve the LOS (Line of Sight) accuracy goal of approx. m/s, the lidar system must be able to account for the orbiter's velocity (approx. 7750 m/s) and the rotational component of the earth's surface motion (approx. 450 m/s). For SPARCLE this requires knowledge of the attitude (roll, pitch and yaw) of the laser beam axis within an accuracy of 80 microradians. (approx. 15 arcsec). Since SPARCLE can not use a dedicated star tracker from its earth-viewing orbiter bay location, a dedicated GPS/INS (Global Positioning System/Inertial Navigation System) will be attached to the lidar instrument rack. Since even the GPS/INS has unacceptable drifts in attitude information, the SPARCLE team has developed a way to periodically scan the instrument itself to obtain less than 10 microradian (2 arcsec) attitude knowledge accuracy that can then be used to correct the GPS/INS output on a 30 minute basis.

Evaluation of an airborne triple-pulsed 2 μm IPDA lidar for simultaneous and independent atmospheric water vapor and carbon dioxide measurements.

PubMed

Refaat, Tamer F; Singh, Upendra N; Yu, Jirong; Petros, Mulugeta; Ismail, Syed; Kavaya, Michael J; Davis, Kenneth J

2015-02-20

Water vapor and carbon dioxide are the most dominant greenhouse gases directly contributing to the Earth's radiation budget and global warming. A performance evaluation of an airborne triple-pulsed integrated path differential absorption (IPDA) lidar system for simultaneous and independent monitoring of atmospheric water vapor and carbon dioxide column amounts is presented. This system leverages a state-of-the-art Ho:Tm:YLF triple-pulse laser transmitter operating at 2.05 μm wavelength. The transmitter provides wavelength tuning and locking capabilities for each pulse. The IPDA lidar system leverages a low risk and technologically mature receiver system based on InGaAs pin detectors. Measurement methodology and wavelength setting are discussed. The IPDA lidar return signals and error budget are analyzed for airborne operation on-board the NASA B-200. Results indicate that the IPDA lidar system is capable of measuring water vapor and carbon dioxide differential optical depth with 0.5% and 0.2% accuracy, respectively, from an altitude of 8 km to the surface and with 10 s averaging. Provided availability of meteorological data, in terms of temperature, pressure, and relative humidity vertical profiles, the differential optical depth conversion into weighted-average column dry-air volume-mixing ratio is also presented.

Coherent Doppler lidar for automated space vehicle rendezvous, stationkeeping and capture

NASA Technical Reports Server (NTRS)

Bilbro, James A.

1991-01-01

The inherent spatial resolution of laser radar makes ladar or lidar an attractive candidate for Automated Rendezvous and Capture application. Previous applications were based on incoherent lidar techniques, requiring retro-reflectors on the target vehicle. Technology improvements (reduced size, no cryogenic cooling requirement) have greatly enhanced the construction of coherent lidar systems. Coherent lidar permits the acquisition of non-cooperative targets at ranges that are limited by the detection capability rather than by the signal-to-noise ratio (SNR) requirements. The sensor can provide translational state information (range, velocity, and angle) by direct measurement and, when used with any array detector, also can provide attitude information by Doppler imaging techniques. Identification of the target is accomplished by scanning with a high pulse repetition frequency (dependent on the SNR). The system performance is independent of range and should not be constrained by sun angle. An initial effort to characterize a multi-element detection system has resulted in a system that is expected to work to a minimum range of 1 meter. The system size, weight and power requirements are dependent on the operating range; 10 km range requires a diameter of 3 centimeters with overall size at 3 x 3 x 15 to 30 cm, while 100 km range requires a 30 cm diameter.

LiDAR Vegetation Investigation and Signature Analysis System (LVISA)

NASA Astrophysics Data System (ADS)

Höfle, Bernhard; Koenig, Kristina; Griesbaum, Luisa; Kiefer, Andreas; Hämmerle, Martin; Eitel, Jan; Koma, Zsófia

2015-04-01

Our physical environment undergoes constant changes in space and time with strongly varying triggers, frequencies, and magnitudes. Monitoring these environmental changes is crucial to improve our scientific understanding of complex human-environmental interactions and helps us to respond to environmental change by adaptation or mitigation. The three-dimensional (3D) description of the Earth surface features and the detailed monitoring of surface processes using 3D spatial data have gained increasing attention within the last decades, such as in climate change research (e.g., glacier retreat), carbon sequestration (e.g., forest biomass monitoring), precision agriculture and natural hazard management. In all those areas, 3D data have helped to improve our process understanding by allowing quantifying the structural properties of earth surface features and their changes over time. This advancement has been fostered by technological developments and increased availability of 3D sensing systems. In particular, LiDAR (light detection and ranging) technology, also referred to as laser scanning, has made significant progress and has evolved into an operational tool in environmental research and geosciences. The main result of LiDAR measurements is a highly spatially resolved 3D point cloud. Each point within the LiDAR point cloud has a XYZ coordinate associated with it and often additional information such as the strength of the returned backscatter. The point cloud provided by LiDAR contains rich geospatial, structural, and potentially biochemical information about the surveyed objects. To deal with the inherently unorganized datasets and the large data volume (frequently millions of XYZ coordinates) of LiDAR datasets, a multitude of algorithms for automatic 3D object detection (e.g., of single trees) and physical surface description (e.g., biomass) have been developed. However, so far the exchange of datasets and approaches (i.e., extraction algorithms) among LiDAR users lacks behind. We propose a novel concept, the LiDAR Vegetation Investigation and Signature Analysis System (LVISA), which shall enhance sharing of i) reference datasets of single vegetation objects with rich reference data (e.g., plant species, basic plant morphometric information) and ii) approaches for information extraction (e.g., single tree detection, tree species classification based on waveform LiDAR features). We will build an extensive LiDAR data repository for supporting the development and benchmarking of LiDAR-based object information extraction. The LiDAR Vegetation Investigation and Signature Analysis System (LVISA) uses international web service standards (Open Geospatial Consortium, OGC) for geospatial data access and also analysis (e.g., OGC Web Processing Services). This will allow the research community identifying plant object specific vegetation features from LiDAR data, while accounting for differences in LiDAR systems (e.g., beam divergence), settings (e.g., point spacing), and calibration techniques. It is the goal of LVISA to develop generic 3D information extraction approaches, which can be seamlessly transferred to other datasets, timestamps and also extraction tasks. The current prototype of LVISA can be visited and tested online via http://uni-heidelberg.de/lvisa. Video tutorials provide a quick overview and entry into the functionality of LVISA. We will present the current advances of LVISA and we will highlight future research and extension of LVISA, such as integrating low-cost LiDAR data and datasets acquired by highly temporal scanning of vegetation (e.g., continuous measurements). Everybody is invited to join the LVISA development and share datasets and analysis approaches in an interoperable way via the web-based LVISA geoportal.

KML-Based Access and Visualization of High Resolution LiDAR Topography

NASA Astrophysics Data System (ADS)

Crosby, C. J.; Blair, J. L.; Nandigam, V.; Memon, A.; Baru, C.; Arrowsmith, J. R.

2008-12-01

Over the past decade, there has been dramatic growth in the acquisition of LiDAR (Light Detection And Ranging) high-resolution topographic data for earth science studies. Capable of providing digital elevation models (DEMs) more than an order of magnitude higher resolution than those currently available, LiDAR data allow earth scientists to study the processes that contribute to landscape evolution at resolutions not previously possible yet essential for their appropriate representation. These datasets also have significant implications for earth science education and outreach because they provide an accurate representation of landforms and geologic hazards. Unfortunately, the massive volume of data produced by LiDAR mapping technology can be a barrier to their use. To make these data available to a larger user community, we have been exploring the use of Keyhole Markup Language (KML) and Google Earth to provide access to LiDAR data products and visualizations. LiDAR digital elevation models are typically delivered in a tiled format that lends itself well to a KML-based distribution system. For LiDAR datasets hosted in the GEON OpenTopography Portal (www.opentopography.org) we have developed KML files that show the extent of available LiDAR DEMs and provide direct access to the data products. Users interact with these KML files to explore the extent of the available data and are able to select DEMs that correspond to their area of interest. Selection of a tile loads a download that the user can then save locally for analysis in their software of choice. The GEON topography system also has tools available that allow users to generate custom DEMs from LiDAR point cloud data. This system is powerful because it enables users to access massive volumes of raw LiDAR data and to produce DEM products that are optimized to their science applications. We have developed a web service that converts the custom DEM models produced by the system to a hillshade that is delivered to the user as a KML groundoverlay. The KML product enables users to quickly and easily visualize the DEMs in Google Earth. By combining internet-based LiDAR data processing with KML visualization products, users are able to execute computationally intensive data sub-setting, processing and visualization without having local access to computing resources, GIS software, or data processing expertise. Finally, GEON has partnered with the US Geological Survey to generate region-dependant network linked KML visualizations for large volumes of LiDAR derived hillshades of the Northern San Andreas fault system. These data, acquired by the NSF-funded GeoEarthScope project, offer an unprecedented look at active faults in the northern portion of the San Andreas system. Through the region-dependant network linked KML, users can seamlessly access 1 meter hillshades (both 315 and 45 degree sun angles) for the full 1400 square kilometer dataset, without downloading huge volumes of data. This type of data access has great utility for users ranging from earthquake scientists to K-12 educators who wish to introduce cutting edge real world data into their earth science lessons.

a Brief Climatology of Cirrus LIDAR Ratios Measured by High Spectral Resolution LIDAR

NASA Astrophysics Data System (ADS)

Kuehn, R.; Holz, R.; Hair, J. W.; Vaughan, M. A.; Eloranta, E. W.

2015-12-01

Our ability to detect and probe the vertical extent of cirrus was hugely improved with the launch of the NASA-CNES CALIPSO mission in April 2006. However, our skill at retrieving the optical properties of the cirrus detected by the CALIPSO lidar is not yet commensurate with our detection abilities. As with any new observing system, CALIPSO faces challenges and uncertainties in the retrieval of the geophysical parameters from its fundamental measurements. Specifically, extinction and optical depth retrievals for elastic backscatter lidars like CALIPSO typically rely on a priori assumptions about layer-mean extinction-to-backscatter ratios (AKA lidar ratios), which can vary regionally and for which uncertainties are high. To improve CALIPSO optical properties retrievals, we show High Spectral Resolution Lidar (HSRL) measurements acquired with systems from the University of Wisconsin and NASA Langley. HSRLs can directly determine ice cloud extinction and lidar ratio by separately measuring the molecular and particulate components of the total backscattered signal, thus largely eliminating many of the uncertainties inherent in elastic backscatter retrievals. These measurements were acquired during the SEAC4RS (Huntsville, AL, USA and Singapore), and FRAPPE/DISCOVER-AQ 2014 (BAO tower near Boulder, CO, USA) field campaigns, and an intensive operations period in Hampton, VA, USA.

Differential Absorption Lidar to Measure Subhourly Variation of Tropospheric Ozone Profiles

NASA Technical Reports Server (NTRS)

Kuang, Shi; Burris, John F.; Newchurch, Michael J.; Johnson, Steve; Long, Stephania

2011-01-01

A tropospheric ozone Differential Absorption Lidar system, developed jointly by The University of Alabama in Huntsville and the National Aeronautics and Space Administration, is making regular observations of ozone vertical distributions between 1 and 8 km with two receivers under both daytime and nighttime conditions using lasers at 285 and 291 nm. This paper describes the lidar system and analysis technique with some measurement examples. An iterative aerosol correction procedure reduces the retrieval error arising from differential aerosol backscatter in the lower troposphere. Lidar observations with coincident ozonesonde flights demonstrate that the retrieval accuracy ranges from better than 10% below 4 km to better than 20% below 8 km with 750-m vertical resolution and 10-min 17 temporal integration.

Airborne LiDAR : a new source of traffic flow data.

DOT National Transportation Integrated Search

2005-10-01

LiDAR (or airborne laser scanning) systems became a dominant player in high-precision spatial data acquisition : to efficiently create DEM/DSM in the late 90's. With increasing point density, new systems are now able to : support object extraction, s...

Airborne LiDAR : a new source of traffic flow data.

DOT National Transportation Integrated Search

2005-10-01

LiDAR (or airborne laser scanning) systems became a dominant player in high-precision spatial data acquisition : to efficiently create DEM/DSM in the late 90s. With increasing point density, new systems are now able to : support object extraction, ...

Calculation of the overlap factor for scanning LiDAR based on the tridimensional ray-tracing method.

PubMed

Chen, Ruiqiang; Jiang, Yuesong; Wen, Luhong; Wen, Donghai

2017-06-01

The overlap factor is used to evaluate the LiDAR light collection ability. Ranging LiDAR is mainly determined by the optical configuration. However, scanning LiDAR, equipped with a scanning mechanism to acquire a 3D coordinate points cloud for a specified target, is essential in considering the scanning effect at the same time. Otherwise, scanning LiDAR will reduce the light collection ability and even cannot receive any echo. From this point of view, we propose a scanning LiDAR overlap factor calculation method based on the tridimensional ray-tracing method, which can be applied to scanning LiDAR with any special laser intensity distribution, any type of telescope (reflector, refractor, or mixed), and any shape obstruction (i.e., the reflector of a coaxial optical system). A case study for our LiDAR with a scanning mirror is carried out, and a MATLAB program is written to analyze the laser emission and reception process. Sensitivity analysis is carried out as a function of scanning mirror rotation speed and detector position, and the results guide how to optimize the overlap factor for our LiDAR. The results of this research will have a guiding significance in scanning LiDAR design and assembly.

Innovative High-Accuracy Lidar Bathymetric Technique for the Frequent Measurement of River Systems

NASA Astrophysics Data System (ADS)

Gisler, A.; Crowley, G.; Thayer, J. P.; Thompson, G. S.; Barton-Grimley, R. A.

2015-12-01

Lidar (light detection and ranging) provides absolute depth and topographic mapping capability compared to other remote sensing methods, which is useful for mapping rapidly changing environments such as riverine systems. Effectiveness of current lidar bathymetric systems is limited by the difficulty in unambiguously identifying backscattered lidar signals from the water surface versus the bottom, limiting their depth resolution to 0.3-0.5 m. Additionally these are large, bulky systems that are constrained to expensive aircraft-mounted platforms and use waveform-processing techniques requiring substantial computation time. These restrictions are prohibitive for many potential users. A novel lidar device has been developed that allows for non-contact measurements of water depth down to 1 cm with an accuracy and precision of < 1 cm by exploiting the polarization properties of the light-surface interaction. This system can transition seamlessly from ranging over land to shallow to deep water allowing for shoreline charting, measuring water volume, mapping bottom topology, and identifying submerged objects. The scalability of the technique opens up the ability for handheld or UAS-mounted lidar bathymetric systems, which provides for potential applications currently unavailable to the community. The high laser pulse repetition rate allows for very fine horizontal resolution while the photon-counting technique permits real-time depth measurement and object detection. The enhanced measurement capability, portability, scalability, and relatively low-cost creates the opportunity to perform frequent high-accuracy monitoring and measuring of aquatic environments which is crucial for understanding how rivers evolve over many timescales. Results from recent campaigns measuring water depth in flowing creeks and murky ponds will be presented which demonstrate that the method is not limited by rough water surfaces and can map underwater topology through moderately turbid water.

Lidar measurements from space for tropospheric chemistry investigations: Summary of workshop overview presentation

NASA Technical Reports Server (NTRS)

Browell, Edward V.

1987-01-01

Over the past decade, NASA has played a lead role in defining the scientific objectives and technology requirements for spaceborne lidar investigations of the atmosphere. An assessment of the potential for conducting lidar measurements from space for investigations that pertain specifically to tropospheric chemistry is presented. A description of potential lidar measurement techniques is given, and the scientific requirements for tropospheric chemistry are reviewed. The current status of airborne lidar measurements of aerosols, O3, and H2O is discussed, and a brief description of the evolution of lidar technology to space is given. Also, the measurement of tropospheric gases with a spaceborne lidar system is evaluated for a wide range of gas species. From this general assessment, it appears feasible to measure aerosols, H2O, O3, NH3, CO, CH4, NO2, atmospheric pressure and temperature, and wind with a lidar from space provided that the appropriate laser and receiver technology is available. For the mid-1990's, it is expected that lidar technology will be available for the measurement of aerosols, H2O, and O3 from a space platform.

Four-wavelength lidar evaluation of particle characteristics and aerosol densities

NASA Astrophysics Data System (ADS)

Uthe, E. E.; Livingston, J. M.; Delateur, S. A.; Nielsen, N. B.

1985-06-01

The SRI International four-wavelength (0.53, 1.06, 3.8, 10.6 micron) lidar systems was used during the SNOW-ONE-B and Smoke Week XI/SNOW-TWO field experiments to validate its capabilities in assessing obscurant optical and physical properties. The lidar viewed along a horizontal path terminated by a passive reflector. Data examples were analyzed in terms of time-dependent transmission, wavelength dependence of optical depth, and range-resolved extinction coefficients. Three methods were used to derive extinction data from the lidar signatures. These were target method, Klett method and experimental data method. The results of the field and analysis programs are reported in the journal and conference papers that are appended to this report, and include: comparison study of lidar extinction methods, submitted to applied optics, error analysis of lidar solution techniques for range-resolved extinction coefficients based on observational data, smoke/obscurants symposium 9, Four--Wavelength Lidar Measurements from smoke week 6/SNOW-TWO, smoke/obscurants symposium 8, SNOW-ONE-B multiple-wavelength lidar measurements. Snow symposium 3, and lidar applications for obscurant evaluations, smoke/obscurants Symposium 7. The report also provides a summary of background work leading to this project, and of project results.

Double-Edge Molecular Measurement of Lidar Wind Profiles in the VALID Campaign

NASA Technical Reports Server (NTRS)

Korb, C. Laurence; Flesia, Cristina; Lolli, Simone; Hirt, Christian

2000-01-01

We have developed a transportable container based direct detection Doppler lidar based on the double-edge molecular technique. The pulsed solid state system was built at the University of Geneva. It was used to make range resolved measurements of the atmospheric wind field as part of the VALID campaign at the Observatoire de Haute Provence in Provence, France in July 1999. Comparison of our lidar wind measurements, which were analyzed without knowledge of the results of rawinsonde measurements made under the supervision of ESA, show good agreement with these rawinsondes. These are the first Doppler lidar field measurements made with an eyesafe direct detection molecular-based system at 355 nm and serve as a demonstrator for future spaceborne direct detection wind systems such as the Atmospheric Dynamics mission. Winds are an important contributor to sea surface temperature measurements made with the Tropical Rainfall Measuring Mission (TRMM) and also affect the TRMM rainfall estimates.

Rectangular Relief Diffraction Gratings for Coherent Lidar Beam Deflection

NASA Technical Reports Server (NTRS)

Cole, H. J.; Dixit, S. N.; Shore, B. W.; Chambers, D. M.; Britten, J. A.; Kavaya, M. J.

1999-01-01

LIDAR systems require a light transmitting system for sending a laser light pulse into space and a receiving system for collecting the retro-scattered light, separating it from the outgoing beam and analyzing the received signal for calculating wind velocities. Currently, a shuttle manifested coherent LIDAR experiment called SPARCLE (SPAce Readiness Coherent Lidar Experiment) includes a silicon wedge (or prism) in its design in order to deflect the outgoing beam 30 degrees relative to the incident direction. The intent of this paper is to present two optical design approaches that may enable the replacement of the optical wedge component (in future, larger aperture, post-SPARCLE missions) with a surface relief transmission diffraction grating. Such a grating could be etched into a lightweight, flat, fused quartz substrate. The potential advantages of a diffractive beam deflector include reduced weight, reduced power requirements for the driving scanning motor, reduced optical sensitivity to thermal gradients, and increased dynamic stability.

Lidar/DIAL detection of acetone at 3.3 μm by a tunable OPO laser system

NASA Astrophysics Data System (ADS)

Puiu, A.; Fiorani, L.; Rosa, O.; Borelli, R.; Pistilli, M.; Palucci, A.

2014-08-01

In this paper we report, for the first time to our knowledge, on lidar/DIAL detection of acetone vapors at 3.3 μm by means of an optical parametric tunable laser system. After a preliminary spectroscopic study in an absorption cell, the feasibility of a differential absorption (DIAL) lidar for the detection of acetone vapors has been investigated in the laboratory, simulating the experimental conditions of a field campaign. Having in mind measurements in a real scenario, a study of possible atmospheric intereferents has been performed, looking for all known compounds that share acetone IR absorption in the spectral band selected for its detection. Possible interfering species from urban and industrial atmospheres were investigated and limits of acetone detection in both environments were identified. This study confirmed that a lidar system can detect a low concentration of acetone at considerable distances.

Evaluation of single photon and Geiger mode Lidar for the 3D Elevation Program

USGS Publications Warehouse

Stoker, Jason M.; Abdullah, Qassim; Nayegandhi, Amar; Winehouse, Jayna

2016-01-01

Data acquired by Harris Corporation’s (Melbourne, FL, USA) Geiger-mode IntelliEarth™ sensor and Sigma Space Corporation’s (Lanham-Seabrook, MD, USA) Single Photon HRQLS sensor were evaluated and compared to accepted 3D Elevation Program (3DEP) data and survey ground control to assess the suitability of these new technologies for the 3DEP. While not able to collect data currently to meet USGS lidar base specification, this is partially due to the fact that the specification was written for linear-mode systems specifically. With little effort on part of the manufacturers of the new lidar systems and the USGS Lidar specifications team, data from these systems could soon serve the 3DEP program and its users. Many of the shortcomings noted in this study have been reported to have been corrected or improved upon in the next generation sensors.

Measurements of fluorescent aerosols using a mutil-channel lidar spectrometer system during DUBI 2016 Campaign

NASA Astrophysics Data System (ADS)

Huang, Z.; Huang, J.; Zhou, T.; Shi, J.; Sugimoto, N.; Tang, K.

2016-12-01

Atmospheric bioaerosols are relevant for public health and may play an important role in the climate system. Previous studies have shown that abundant bioaerosols (such as microorganisms) injected into the atmosphere along with dust events, could affect leeward ecosystem and human health, even induce globe climate change. However, the challenge in quantifying bioaerosol climate effects (e.g., radiative forcing and aerosol-cloud interactions) arises from large spatial and temporal heterogeneity of their concentrations, compositions, sizes, shape and optical properties. Lidar, as one of most advanced active remote sensing, is used to offer some remarkable advantages for determining the vertical structure of atmospheric aerosols and their related optical properties. In order to investigate the characterization of atmospheric bioaerosols along transported pathways of dust aerosols, we carried out DUBI (DUst BIoaerosol) 2016 Campaign over Northern China in spring of 2016. Lots of instruments, including bioaerosol sampling, lidar as well as others, were installed at three sites­ (Erenhot, Zhangbei and Jinan) simultaneously. A multi-channel lidar spectrometer system was developed to observe Mie, Raman scattering and laser-induced fluorescence excitation at 355 nm from the atmosphere. The lidar system operated polarization measurements at 355nm, aiming to identify dust particles from other aerosols. It employs a high power pulsed laser with energy of 80mJ at 355nm and a received telescope with 350mm diameter. The receiver could simultaneously detect a wide fluorescent spectrum between 360nm and 720nm with spectral resolution 5.7 nm using two spectrometers simultaneously. The spectrometer mainly includes an F/3.7 Crossed Czerny-Turner spectrographs, a grating (1200 gr/mm) and a PMT array with 32 photocathode elements. Vertical structure of fluorescent aerosols in the atmosphere was observed by the developed lidar system at Zhangbei during DUBI 2016 Campaign. It has been proved that the developed lidar could detect the fluorescent aerosols with high temporal and spatial resolutions. Moreover, characterization of bioaerosols was investigated from co-located bioaerosol sampling analysis.

Design and Performance of a Multiwavelength Airborne Polarimetric Lidar for Vegetation Remote Sensing

NASA Astrophysics Data System (ADS)

Tan, Songxin; Narayanan, Ram M.

2004-04-01

The University of Nebraska has developed a multiwavelength airborne polarimetric lidar (MAPL) system to support its Airborne Remote Sensing Program for vegetation remote sensing. The MAPL design and instrumentation are described in detail. Characteristics of the MAPL system include lidar waveform capture and polarimetric measurement capabilities, which provide enhanced opportunities for vegetation remote sensing compared with current sensors. Field tests were conducted to calibrate the range measurement. Polarimetric calibration of the system is also discussed. Backscattered polarimetric returns, as well as the cross-polarization ratios, were obtained from a small forested area to validate the system's ability for vegetation canopy detection. The system has been packaged to fly abroad a Piper Saratoga aircraft for airborne vegetation remote sensing applications.

An Ozone Differential Absorption Lidar (DIAL) Receiver System for Use on Unpiloted Atmospheric Vehicles

NASA Technical Reports Server (NTRS)

DeYoung, Russell J.; Goldschmidt, Soenke

1999-01-01

Measurements of global atmosphere ozone concentrations call for flexible lidar systems that can be operated from an unpiloted atmospheric vehicle (UAV) to reduce the cost of measurement missions. A lidar receiver system consisting of a fiber-optic-coupled telescope has been designed and tested for this purpose. The system weight is 13 kg and its volume of 0.06 m 3 would fit into the payload compartment of a Perseus B UAV. The optical efficiency of the telescope is 37 percent at 288 nm and 64 percent at 300 nm. Atmospheric measurements with a DIAL laser system have been performed, and the measured ozone density has matched the data from ozonesondes to an altitude of 7 km.

Lidar In-Space Technology Experiment (LITE) - NASA's first in-space lidar system for atmospheric research

NASA Technical Reports Server (NTRS)

Couch, Richard H.; Rowland, Carroll W.; Ellis, K. Scott; Blythe, Michael P.; Regan, Curtis P.; Koch, Michael R.; Antill, Charles W.; Kitchen, Wayne L.; Cox, John W.; Delorme, Joseph F.

1991-01-01

Engineering aspects are presented of the design, fabrication, integration, and operation of the Lidar In-Space Technology Experiment (LITE) for flight aboard the Space Shuttle in mid-1993. The LITE system is being developed by NASA/Langley Research Center and will be used to detect stratospheric and tropospheric aerosols, probe the planetary boundary layer, measure cloud top heights, and measure atmospheric temperature and density in the 10- to 40-km range. The system consists of a nominal telescope receiver 1 meter in diameter, a three-color Nd:YAG laser transmitter, and the system electronics. The system makes extensive use of Space Shuttle resources for electrical power, thermal control, and command and data handling.

Use of airborne and terrestrial lidar to detect ground displacement hazards to water systems

USGS Publications Warehouse

Stewart, J.P.; Hu, Jiawen; Kayen, R.E.; Lembo, A.J.; Collins, B.D.; Davis, C.A.; O'Rourke, T. D.

2009-01-01

We investigate the use of multiepoch airborne and terrestrial lidar to detect and measure ground displacements of sufficient magnitude to damage buried pipelines and other water system facilities that might result, for example, from earthquake or rainfall-induced landslides. Lidar scans are performed at three sites with coincident measurements by total station surveying. Relative horizontal accuracy is evaluated by measurements of lateral dimensions of well defined objects such as buildings and tanks; we find misfits ranging from approximately 5 to 12 cm, which is consistent with previous work. The bias and dispersion of lidar elevation measurements, relative to total station surveying, is assessed at two sites: (1) a power plant site (PP2) with vegetated steeply sloping terrain; and (2) a relatively flat and unvegetated site before and after trenching operations were performed. At PP2, airborne lidar showed minimal elevation bias and a standard deviation of approximately 70 cm, whereas terrestrial lidar did not produce useful results due to beam divergence issues and inadequate sampling of the study region. At the trench site, airborne lidar showed minimal elevation bias and reduced standard deviation relative to PP2 (6-20 cm), whereas terrestrial lidar was nearly unbiased with very low dispersion (4-6 cm). Pre- and posttrench bias-adjusted normalized residuals showed minimal to negligible correlation, but elevation change was affected by relative bias between epochs. The mean of elevation change bias essentially matches the difference in means of pre- and posttrench elevation bias, whereas elevation change standard deviation is sensitive to the dispersion of individual epoch elevations and their correlation coefficient. The observed lidar bias and standard deviations enable reliable detection of damaging ground displacements for some pipelines types (e.g., welded steel) but not all (e.g., concrete with unwelded, mortared joints). ?? ASCE 2009.

Auto-locking waveguide amplifier system for lidar and magnetometric applications

NASA Astrophysics Data System (ADS)

Pouliot, A.; Beica, H. C.; Carew, A.; Vorozcovs, A.; Carlse, G.; Kumarakrishnan, A.

2018-02-01

We describe a compact waveguide amplifier system that is suitable for optically pumping rubidium magnetometers. The system consists of an auto-locking vacuum-sealed external cavity diode laser, a semiconductor tapered amplifier and a pulsing unit based on an acousto-optic modulator. The diode laser utilises optical feedback from an interference filter to narrow the linewidth of an inexpensive laser diode to 500 kHz. This output is scannable over an 8 GHz range (at 780 nm) and can be locked without human intervention to any spectral marker in an expandable library of reference spectra, using the autolocking controller. The tapered amplifier amplifies the output from 50 mW up to 2 W with negligible distortions in the spectral quality. The system can operate at visible and near infrared wavelengths with MHz repetition rates. We demonstrate optical pumping of rubidium vapour with this system for magnetometric applications. The magnetometer detects the differential absorption of two orthogonally polarized components of a linearly polarized probe laser following optical pumping by a circularly polarized pump laser. The differential absorption signal is studied for a range of pulse lengths, pulse amplitudes and DC magnetic fields. Our results suggest that this laser system is suitable for optically pumping spin-exchange free magnetometers.

Optics of the ozone lidar ELSA

NASA Technical Reports Server (NTRS)

Porteneuve, J.

1992-01-01

In order to study the ozone layer in the Arctic, we have to define a new optical concept for a lidar. It was necessary to build a transportable system with a large collecting surface in a minimum of volume. It was too useful to have a multichannel receptor. A description of the Emettor Receptor System, collecting system, and analysis system is provided.

Compact, highly efficient, single-frequency 25W, 2051nm Tm fiber-based MOPA for CO2 trace-gas laser space transmitter

NASA Astrophysics Data System (ADS)

Engin, Doruk; Chuang, Ti; Litvinovitch, Slava; Storm, Mark

2017-08-01

Fibertek has developed and demonstrated an ideal high-power; low-risk; low-size, weight, and power (SWaP) 2051 nm laser design meeting the lidar requirements for satellite-based global measurement of carbon dioxide (CO2). The laser design provides a path to space for either a coherent lidar approach being developed by NASA Jet Propulsion Laboratory (JPL)1,2 or an Integrated Path Differential Lidar (IPDA) approach developed by Harris Corp using radio frequency (RF) modulation and being flown as part of a NASA Earth Venture Suborbital Mission—NASA's Atmospheric Carbon and Transport - America.3,4 The thulium (Tm) fiber laser amplifies a <500 kHz linewidth distributed feedback (DFB) laser up to 25 W average power in a polarization maintaining (PM) fiber. The design manages and suppresses all deleterious non-linear effects that can cause linewidth broadening or amplified spontaneous emission (ASE) and meets all lidar requirements. We believe the core laser components, architecture, and design margins can support a coherent or IPDA lidar 10-year space mission. With follow-on funding Fibertek can adapt an existing space-based Technology Readiness Level 6 (TRL-6), 20 W erbium fiber laser package for this Tm design and enable a near-term space mission with an electrical-to-optical (e-o) efficiency of <20%. A cladding-pumped PM Tm fiber-based amplifier optimized for high efficiency and high-power operation at 2051 nm is presented. The two-stage amplifier has been demonstrated to achieve 25 W average power and <16 dB polarization extinction ratio (PER) out of a single-mode PM fiber using a <500 kHz linewidth JPL DFB laser5-7 and 43 dB gain. The power amplifier's optical conversion efficiency is 53%. An internal efficiency of 58% is calculated after correcting for passive losses. The two-stage amplifier sustains its highly efficient operation for a temperature range of 5-40°C. The absence of stimulated Brillouin scattering (SBS) for the narrow linewidth amplification shows promise for further power scaling.

A comparison of lidar inversion methods for cirrus applications

NASA Technical Reports Server (NTRS)

Elouragini, Salem; Flamant, Pierre H.

1992-01-01

Several methods for inverting the lidar equation are suggested as means to derive the cirrus optical properties (beta backscatter, alpha extinction coefficients, and delta optical depth) at one wavelength. The lidar equation can be inverted in a linear or logarithmic form; either solution assumes a linear relationship: beta = kappa(alpha), where kappa is the lidar ratio. A number of problems prevent us from calculating alpha (or beta) with a good accuracy. Some of these are as follows: (1) the multiple scattering effect (most authors neglect it); (2) an absolute calibration of the lidar system (difficult and sometimes not possible); (3) lack of accuracy on the lidar ratio k (taken as constant, but in fact it varies with range and cloud species); and (4) the determination of boundary condition for logarithmic solution which depends on signal to noise ration (SNR) at cloud top. An inversion in a linear form needs an absolute calibration of the system. In practice one uses molecular backscattering below the cloud to calibrate the system. This method is not permanent because the lower atmosphere turbidity is variable. For a logarithmic solution, a reference extinction coefficient (alpha(sub f)) at cloud top is required. Several methods to determine alpha(sub f) were suggested. We tested these methods at low SNR. This led us to propose two new methods referenced as S1 and S2.

Closed-loop control of gimbal-less MEMS mirrors for increased bandwidth in LiDAR applications

NASA Astrophysics Data System (ADS)

Milanović, Veljko; Kasturi, Abhishek; Yang, James; Hu, Frank

2017-05-01

In 2016, we presented a low SWaP wirelessly controlled MEMS mirror-based LiDAR prototype which utilized an OEM laser rangefinder for distance measurement [1]. The MEMS mirror was run in open loop based on its exceptionally fast design and high repeatability performance. However, to further extend the bandwidth and incorporate necessary eyesafety features, we recently focused on providing mirror position feedback and running the system in closed loop control. Multiple configurations of optical position sensors, mounted on both the front- and the back-side of the MEMS mirror, have been developed and will be presented. In all cases, they include a light source (LED or laser) and a 2D photosensor. The most compact version is mounted on the backside of the MEMS mirror ceramic package and can "view" the mirror's backside through openings in the mirror's PCB and its ceramic carrier. This version increases the overall size of the MEMS mirror submodule from 12mm x 12mm x 4mm to 15mm x 15mm x 7mm. The sensors also include optical and electronic filtering to reduce effects of any interference from the application laser illumination. With relatively simple FPGA-based PID control running at the sample rate of 100 kHz, we could configure the overall response of the system to fully utilize the MEMS mirror's native bandwidth which extends well beyond its first resonance. When compared to the simple open loop method of suppressing overshoot and ringing which significantly limits bandwidth utilization, running the mirrors in closed loop control increased the bandwidth to nearly 3.7 times. A 2.0mm diameter integrated MEMS mirror with a resonant frequency of 1300 Hz was limited to 500Hz bandwidth in open loop driving but was increased to 3kHz bandwidth with the closed loop controller. With that bandwidth it is capable of very sharply defined uniform-velocity scans (sawtooth or triangle waveforms) which are highly desired in scanned mirror LiDAR systems. A 2.4mm diameter mirror with +/-12° of scan angle achieves over 1.3kHz of flat response, allowing sharp triangle waveforms even at 300Hz (600 uniform velocity lines per second). The same methodology is demonstrated with larger, bonded mirrors. Here closed loop control is more challenging due to the additional resonance and a more complex system dynamic. Nevertheless, results are similar - a 5mm diameter mirror bandwidth was increased from 150Hz to 500Hz.

Recent lidar measurements of stratospheric ozone and temperature within the network for the detection of stratospheric change

NASA Technical Reports Server (NTRS)

Mcgee, Thomas J.; Ferrare, Richard; Butler, James J.; Frost, Robert L.; Gross, Michael; Margitan, James

1991-01-01

The Goddard mobile lidar was deployed at Cannon Air Force Base near Clovis, New Mexico during the Spring of 1990. Measurements of stratospheric ozone and temperature were made over a period of six weeks. Data from the lidar system is compared with data from a balloon-borne, ultraviolet instrument launched from nearby Ft. Sumner, New Mexico. Along with several improvements to this instrument which are now underway, a second lidar dedicated to temperature and aerosol measurements is now being developed.

Time Shifted PN Codes for CW Lidar, Radar, and Sonar

NASA Technical Reports Server (NTRS)

Campbell, Joel F. (Inventor); Prasad, Narasimha S. (Inventor); Harrison, Fenton W. (Inventor); Flood, Michael A. (Inventor)

2013-01-01

A continuous wave Light Detection and Ranging (CW LiDAR) system utilizes two or more laser frequencies and time or range shifted pseudorandom noise (PN) codes to discriminate between the laser frequencies. The performance of these codes can be improved by subtracting out the bias before processing. The CW LiDAR system may be mounted to an artificial satellite orbiting the earth, and the relative strength of the return signal for each frequency can be utilized to determine the concentration of selected gases or other substances in the atmosphere.

A lidar system for measuring atmospheric pressure and temperature profiles

NASA Technical Reports Server (NTRS)

Schwemmer, Geary K.; Dombrowski, Mark; Korb, C. Laurence; Milrod, Jeffry; Walden, Harvey

1987-01-01

The design and operation of a differential absorption lidar system capable of remotely measuring the vertical structure of tropospheric pressure and temperature are described. The measurements are based on the absorption by atmospheric oxygen of the spectrally narrowband output of two pulsed alexandrite lasers. Detailed laser output spectral characteristics, which are critical to successful lidar measurements, are presented. Spectral linewidths of 0.026 and 0.018 per cm for the lasers were measured with over 99.99 percent of the energy contained in three longitudinal modes.

The evaluation of a shuttle borne lidar experiment to measure the global distribution of aerosols and their effect on the atmospheric heat budget

NASA Technical Reports Server (NTRS)

Shipley, S. T.; Joseph, J. H.; Trauger, J. T.; Guetter, P. J.; Eloranta, E. W.; Lawler, J. E.; Wiscombe, W. J.; Odell, A. P.; Roesler, F. L.; Weinman, J. A.

1975-01-01

A shuttle-borne lidar system is described, which will provide basic data about aerosol distributions for developing climatological models. Topics discussed include: (1) present knowledge of the physical characteristics of desert aerosols and the absorption characteristics of atmospheric gas, (2) radiative heating computations, and (3) general circulation models. The characteristics of a shuttle-borne radar are presented along with some laboratory studies which identify schemes that permit the implementation of a high spectral resolution lidar system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldsmith, John

High Spectral Resolution Lidar (HSRL) systems provide vertical profiles of optical depth, backscatter cross-section, depolarization, and backscatter phase function. All HSRL measurements are absolutely calibrated by reference to molecular scattering, which is measured at each point in the lidar profile. Like the Raman lidar but unlike simple backscatter lidars such as the micropulse lidar, the HSRL can measure backscatter cross-sections and optical depths without prior assumptions about the scattering properties of the atmosphere. The depolarization observations also allow robust discrimination between ice and water clouds. In addition, rigorous error estimates can be computed for all measurements. A very narrow, angularmore » field of view reduces multiple scattering contributions. The small field of view, coupled with a narrow optical bandwidth, nearly eliminates noise due to scattered sunlight. There are two operational U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility HSRL systems, one at the Barrow North Slope of Alaska (NSA) site and the other in the second ARM Mobile Facility (AMF2) collection of instrumentation.« less

In-Flight Thermal Performance of the Lidar In-Space Technology Experiment

NASA Technical Reports Server (NTRS)

Roettker, William

1995-01-01

The Lidar In-Space Technology Experiment (LITE) was developed at NASA s Langley Research Center to explore the applications of lidar operated from an orbital platform. As a technology demonstration experiment, LITE was developed to gain experience designing and building future operational orbiting lidar systems. Since LITE was the first lidar system to be flown in space, an important objective was to validate instrument design principles in such areas as thermal control, laser performance, instrument alignment and control, and autonomous operations. Thermal and structural analysis models of the instrument were developed during the design process to predict the behavior of the instrument during its mission. In order to validate those mathematical models, extensive engineering data was recorded during all phases of LITE's mission. This inflight engineering data was compared with preflight predictions and, when required, adjustments to the thermal and structural models were made to more accurately match the instrument s actual behavior. The results of this process for the thermal analysis and design of LITE are presented in this paper.

IEA Task 32: Wind Lidar Systems for Wind Energy Deployment (LIDAR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuhn, Martin; Trabucchi, Davide; Clifton, Andrew

2016-05-25

Under the International Energy Agency Wind Implementing Agreement (IEA Wind) Task 11, researchers started examining novel applications for remote sensing and the issues around them during the 51st topical expert meeting about remote sensing in January 2007. The 59th topical expert meeting organized by Task 11 in October 2009 was also dedicated to remote sensing, and the first draft of the Task's recommended practices on remote sensing was published in January 2013. The results of the Task 11 topical expert meetings provided solid groundwork for a new IEA Wind Task 32 on wind lidar technologies. Members of the wind communitymore » identified the need to consolidate the knowledge about wind lidar systems to facilitate their use, and to investigate how to exploit the advantages offered by this technology. This was the motivation that led to the start of IEA Wind Task 32 'Lidar Application for Wind Energy Deployment' in November 2011. The kick-off was meeting was held in May 2012.« less

Calibration Technique for Polarization-Sensitive Lidars

NASA Technical Reports Server (NTRS)

Alvarez, J. M.; Vaughan, M. A.; Hostetler, C. A.; Hung, W. H.; Winker, D. M.

2006-01-01

Polarization-sensitive lidars have proven to be highly effective in discriminating between spherical and non-spherical particles in the atmosphere. These lidars use a linearly polarized laser and are equipped with a receiver that can separately measure the components of the return signal polarized parallel and perpendicular to the outgoing beam. In this work we describe a technique for calibrating polarization-sensitive lidars that was originally developed at NASA s Langley Research Center (LaRC) and has been used continually over the past fifteen years. The procedure uses a rotatable half-wave plate inserted into the optical path of the lidar receiver to introduce controlled amounts of polarization cross-talk into a sequence of atmospheric backscatter measurements. Solving the resulting system of nonlinear equations generates the system calibration constants (gain ratio, G, and offset angle, theta) required for deriving calibrated measurements of depolarization ratio from the lidar signals. In addition, this procedure also determines the mean depolarization ratio within the region of the atmosphere that is analyzed. Simulations and error propagation studies show the method to be both reliable and well behaved. Operational details of the technique are illustrated using measurements obtained as part of Langley Research Center s participation in the First ISCCP Regional Experiment (FIRE).

LIDAR pulse coding for high resolution range imaging at improved refresh rate.

PubMed

Kim, Gunzung; Park, Yongwan

2016-10-17

In this study, a light detection and ranging system (LIDAR) was designed that codes pixel location information in its laser pulses using the direct- sequence optical code division multiple access (DS-OCDMA) method in conjunction with a scanning-based microelectromechanical system (MEMS) mirror. This LIDAR can constantly measure the distance without idle listening time for the return of reflected waves because its laser pulses include pixel location information encoded by applying the DS-OCDMA. Therefore, this emits in each bearing direction without waiting for the reflected wave to return. The MEMS mirror is used to deflect and steer the coded laser pulses in the desired bearing direction. The receiver digitizes the received reflected pulses using a low-temperature-grown (LTG) indium gallium arsenide (InGaAs) based photoconductive antenna (PCA) and the time-to-digital converter (TDC) and demodulates them using the DS-OCDMA. When all of the reflected waves corresponding to the pixels forming a range image are received, the proposed LIDAR generates a point cloud based on the time-of-flight (ToF) of each reflected wave. The results of simulations performed on the proposed LIDAR are compared with simulations of existing LIDARs.

LIDAR wind speed measurements at a Taiwan onshore wind park

NASA Astrophysics Data System (ADS)

Wu, Yu-Ting; Lin, Ta-Hui; Hsuan, Chung-Yao; Li, Yu-Cheng; Yang, Ya-Fei; Tai, Tzy-Hwan; Huang, Chien-Cheng

2016-04-01

Measurements of wind speed and wind direction were carried out using a Leosphere Windcube LIDAR system at a Taiwan onshore wind park. The Lidar shot a total of five laser beams to the atmosphere to collect the light-of-sight (LOS) velocity. Four beams were sent successively in four cardinal directions along a 28° scanning cone angle, followed by a fifth, vertical beam. An unchangeable sampling rate of approximately 1.2 Hz was set in the LIDAR system to collect the LOS velocity. The supervisory control and data acquisition (SCADA) data from two GE 1.5 MW wind turbines near the LIDAR deployment site were acquired for the whole measuring period from February 4 to February 16 of 2015. The SCADA data include the blade angular velocity, the wind velocity measured at hub height from an anemometer mounted on the nacelle, the wind turbine yaw angle, and power production; each parameter was recorded as averages over 1-min periods. The data analysis involving the LIDAR measurements and the SCADA data were performed to obtain the turbulent flow statistics. The results show that the turbine power production has significant dependence to the wind speed, wind direction, turbulence intensity and wind shear.

Airborne hyperspectral and LiDAR data integration for weed detection

NASA Astrophysics Data System (ADS)

Tamás, János; Lehoczky, Éva; Fehér, János; Fórián, Tünde; Nagy, Attila; Bozsik, Éva; Gálya, Bernadett; Riczu, Péter

2014-05-01

Agriculture uses 70% of global available fresh water. However, ca. 50-70% of water used by cultivated plants, the rest of water transpirated by the weeds. Thus, to define the distribution of weeds is very important in precision agriculture and horticulture as well. To survey weeds on larger fields by traditional methods is often time consuming. Remote sensing instruments are useful to detect weeds in larger area. In our investigation a 3D airborne laser scanner (RIEGL LMS-Q680i) was used in agricultural field near Sopron to scouting weeds. Beside the airborne LiDAR, hyperspectral imaging system (AISA DUAL) and air photos helped to investigate weed coverage. The LiDAR survey was carried out at early April, 2012, before sprouting of cultivated plants. Thus, there could be detected emerging of weeds and direction of cultivation. However airborne LiDAR system was ideal to detect weeds, identification of weeds at species level was infeasible. Higher point density LiDAR - Terrestrial laser scanning - systems are appropriate to distinguish weed species. Based on the results, laser scanner is an effective tool to scouting of weeds. Appropriate weed detection and mapping systems could contribute to elaborate water and herbicide saving management technique. This publication was supported by the OTKA project K 105789.

Long-range transport of Siberian forest fire smoke to Canada's west coast identified by Lidar observations

NASA Astrophysics Data System (ADS)

Strawbridge, Kevin; Cottle, Paul; McKendry, Ian

2014-05-01

During the summer of 2012, forest fire smoke wasdetected by two CORALNet lidar systems operated by Environment Canada along Canada's west coast. Based on satellite, model and back trajectory analysis it is thought the smoke originated in Boreal Asia as a result of unusually large amounts of Siberian wildfire activity. The CORALNet lidar systems operate autonomously, measuring the vertical profile of aerosols from near ground to 18 km at a vertical resolution of 3 m and 7.5 m and a temporal resolution of 10 s and 60 s at 1064 nm and 532 nm wavelengths respectively. The lidar also measures the depolarization ratio at 532 nm: and indicator of particle shape. The lidars, located at the University of British Columbia in Vancouver and in the village of Whistler, British Columbia observed an increase in the aerosol backscatter ratio in the free troposphere as the Siberian forest fire smoke was transported across the Pacific Ocean into the region. Of particular importance was the increase in ground level particulate due to the mixing of the smoke into the boundary layer, impacting the air quality in southwestern British Columbia. Lidar depolarization ratios in the boundary layer and the free troposphere were consistent with high concentrations of smoke. Detailed lidar observations will be presented along with supporting satellite, model and ground observations revealing the magnitude of the impact on the region.

Mie Lidar for Aerosols and Clouds Monitoring at Otlica Observatory

NASA Astrophysics Data System (ADS)

Gao, F.; Stanič, S.; Bergant, K.; Filipčič, A.; Veberič, D.; Forte, B.

2009-04-01

Aerosol and cloud densities are the most important atmospheric parameters, which significantly influence the atmospheric conditions. The study of their spatial and temporal properties can provide detailed information about the transport processes of the air masses. In recent years, lidar techniques for remote sensing of the atmospheric parameters have been greatly improved. Like the lidar systems of the Pierre Auger Observatory in Argentina (35.2S, 69.1W, 1400 m a.s.l.), the Mie lidar built at Otlica Observatory (45.93N, 13.91E, 945 m a.s.l.) in Slovenia employs the same hardware, including the transmitter, the receiver, and the DAQ system. Due to its high-power laser, large-diameter telescope, and photon-counting data-acquisition technique, the Mie lidar has the potential ability to measure the tropospheric and stratospheric atmospheric conditions, and is suitable for monitoring the changes of the cirrus clouds and atmospheric boundary layer. We have been performing routine atmospheric monitoring experiments with the Otlica Mie lidar since September 2008. Using the techniques of event-averaging, noise-elimination, and data-gluing, the far end of lidar probing range is extended from 30 km up to 40 km. The extinction profiles are calculated using the Klett method and the time-height-intensity plots were made. They clearly show the evolution of atmospheric conditions, especially the motion of the cirrus clouds above Otlica.

Nosql for Storage and Retrieval of Large LIDAR Data Collections

NASA Astrophysics Data System (ADS)

Boehm, J.; Liu, K.

2015-08-01

Developments in LiDAR technology over the past decades have made LiDAR to become a mature and widely accepted source of geospatial information. This in turn has led to an enormous growth in data volume. The central idea for a file-centric storage of LiDAR point clouds is the observation that large collections of LiDAR data are typically delivered as large collections of files, rather than single files of terabyte size. This split of the dataset, commonly referred to as tiling, was usually done to accommodate a specific processing pipeline. It makes therefore sense to preserve this split. A document oriented NoSQL database can easily emulate this data partitioning, by representing each tile (file) in a separate document. The document stores the metadata of the tile. The actual files are stored in a distributed file system emulated by the NoSQL database. We demonstrate the use of MongoDB a highly scalable document oriented NoSQL database for storing large LiDAR files. MongoDB like any NoSQL database allows for queries on the attributes of the document. As a specialty MongoDB also allows spatial queries. Hence we can perform spatial queries on the bounding boxes of the LiDAR tiles. Inserting and retrieving files on a cloud-based database is compared to native file system and cloud storage transfer speed.

Simultaneous Red - Blue Lidar and Airborne Impactor Measurements

NASA Technical Reports Server (NTRS)

McCormick, M. P.; Blifford, I. H.; Fuller, W. H.; Grams, G. W.

1973-01-01

Simultaneous two-color (0.6943 micrometers and 0.3472 micrometers) LIDAR measurements were made in the troposphere and lower stratosphere over Boulder, Colorado during March 1973. In addition, on the evening of March 26, airborne single-stage impactor measurements were made at four altitudes-- 10,500, 25,000, 33,000 and 43,000 feet MSL. These data were integrated at constant altitude for 15,45, 45, and 60 minutes respectively. The LIDAR data were taken with Langley's 48" LIDAR using a dichroic beamsplitter to separate the return at 0.6943 micrometers and 0.3472 micrometers. The analog waveforms for both colors were digitized simultaneously; one on an NCAR data acquisition system and the other on the 48" Langley data acquisition system. A discussion of the preliminary results from these measurements will be presented.

Iodine-filter-based high spectral resolution lidar for atmospheric temperature measurements.

PubMed

Liu, Zhi-Shen; Bi, De-Cang; Song, Xiao-Quan; Xia, Jin-Bao; Li, Rong-Zhong; Wang, Zhang-Jun; She, Chiao-Yao

2009-09-15

This paper presents a method for measuring atmosphere temperature profile using a single iodine filter as frequency discriminator. This high spectral resolution lidar (HSRL) is a system reconfigured with the transmitter of a mobile Doppler wind lidar and with a receiving subsystem redesigned to pass the backscattering optical signal through the iodine cell twice to filter out the aerosol scattering signal and to allow analysis of the molecular scattering spectrum, thus measuring temperatures. We report what are believed to be the first results of vertical temperature profiling from the ground to 16 km altitude by this lidar system (power-aperture product=0.35 Wm(2)). Concurrent observations of an L band radiosonde were carried out on June 14 and August 3, 2008, in good agreement with HSRL temperature profiles.

Designing and Testing a UAV Mapping System for Agricultural Field Surveying

PubMed Central

Skovsen, Søren

2017-01-01

A Light Detection and Ranging (LiDAR) sensor mounted on an Unmanned Aerial Vehicle (UAV) can map the overflown environment in point clouds. Mapped canopy heights allow for the estimation of crop biomass in agriculture. The work presented in this paper contributes to sensory UAV setup design for mapping and textual analysis of agricultural fields. LiDAR data are combined with data from Global Navigation Satellite System (GNSS) and Inertial Measurement Unit (IMU) sensors to conduct environment mapping for point clouds. The proposed method facilitates LiDAR recordings in an experimental winter wheat field. Crop height estimates ranging from 0.35–0.58 m are correlated to the applied nitrogen treatments of 0–300 kgNha. The LiDAR point clouds are recorded, mapped, and analysed using the functionalities of the Robot Operating System (ROS) and the Point Cloud Library (PCL). Crop volume estimation is based on a voxel grid with a spatial resolution of 0.04 × 0.04 × 0.001 m. Two different flight patterns are evaluated at an altitude of 6 m to determine the impacts of the mapped LiDAR measurements on crop volume estimations. PMID:29168783

Project ABLE: (Atmospheric Balloonborne Lidar Experiment)

NASA Astrophysics Data System (ADS)

Shepherd, O.; Aurilio, G.; Bucknam, R. D.; Hurd, A. G.; Sheehan, W. H.

1985-03-01

Project ABLE (Atmospheric Balloonborne Lidar Experiment) is part of the A.F. Geophysics Laboratory's continuing interest in developing techniques for making remote measurements of atmospheric quantities such as density, pressure, temperatures, and wind motions. The system consists of a balloonborne lidar payload designed to measure neutral molecular density as a function of altitude from ground level to 70 km. The lidar provides backscatter data at the doubled and tripled frequencies of a Nd:YAG laser, which will assist in the separation of the molecular and aerosol contributions and subsequent determination of molecular and aerosol contributions and subsequent determination of molecular density vs altitude. The object of this contract was to fabricate and operate in a field test a balloonborne lidar experiment capable of performing nighttime atmospheric density measurements up to 70 km altitude with a resolution of 150 meters. The payload included a frequency-doubled and -tripled Nd:YAG laser with outputs at 355 and 532 nm; a telescoped receiver with PMT detectors; a command-controlled optical pointing system; and support system, including thermal control, telmetry, command, and power. Successful backscatter measurements were made during field operations which included a balloon launch from Roswell, NM and a flight over the White Sands Missile Range.

Designing and Testing a UAV Mapping System for Agricultural Field Surveying.

PubMed

Christiansen, Martin Peter; Laursen, Morten Stigaard; Jørgensen, Rasmus Nyholm; Skovsen, Søren; Gislum, René

2017-11-23

A Light Detection and Ranging (LiDAR) sensor mounted on an Unmanned Aerial Vehicle (UAV) can map the overflown environment in point clouds. Mapped canopy heights allow for the estimation of crop biomass in agriculture. The work presented in this paper contributes to sensory UAV setup design for mapping and textual analysis of agricultural fields. LiDAR data are combined with data from Global Navigation Satellite System (GNSS) and Inertial Measurement Unit (IMU) sensors to conduct environment mapping for point clouds. The proposed method facilitates LiDAR recordings in an experimental winter wheat field. Crop height estimates ranging from 0.35-0.58 m are correlated to the applied nitrogen treatments of 0-300 kg N ha . The LiDAR point clouds are recorded, mapped, and analysed using the functionalities of the Robot Operating System (ROS) and the Point Cloud Library (PCL). Crop volume estimation is based on a voxel grid with a spatial resolution of 0.04 × 0.04 × 0.001 m. Two different flight patterns are evaluated at an altitude of 6 m to determine the impacts of the mapped LiDAR measurements on crop volume estimations.

EAARL coastal topography and imagery–Western Louisiana, post-Hurricane Rita, 2005: First surface

USGS Publications Warehouse

Bonisteel-Cormier, Jamie M.; Wright, Wayne C.; Fredericks, Alexandra M.; Klipp, Emily S.; Nagle, Doug B.; Sallenger, Asbury H.; Brock, John C.

2013-01-01

These remotely sensed, geographically referenced color-infrared (CIR) imagery and elevation measurements of lidar-derived first-surface (FS) topography datasets were produced by the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, Virginia. This project provides highly detailed and accurate datasets of a portion of the Louisiana coastline beachface, acquired post-Hurricane Rita on September 27-28 and October 2, 2005. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the National Aeronautics and Space Administration (NASA) Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color-infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or sub-aerial topography. Specialized filtering algorithms have been implemented to determine the "bare earth" under vegetation from a point cloud of last return elevations. For more information about similar projects, please visit the Lidar for Science and Resource Management Website.

Canadian and U.S. Cooperation for the development of standards and specifications for emerging mapping technologies

USGS Publications Warehouse

Habib, A.; Jarvis, A.; Al-Durgham, M. M.; Lay, J.; Quackenbush, P.; Stensaas, G.; Moe, D.

2007-01-01

The mapping community is witnessing significant advances in available sensors, such as medium format digital cameras (MFDC) and Light Detection and Ranging (LiDAR) systems. In this regard, the Digital Photogrammetry Research Group (DPRG) of the Department of Geomatics Engineering at the University of Calgary has been actively involved in the development of standards and specifications for regulating the use of these sensors in mapping activities. More specifically, the DPRG has been working on developing new techniques for the calibration and stability analysis of medium format digital cameras. This research is essential since these sensors have not been developed with mapping applications in mind. Therefore, prior to their use in Geomatics activies, new standards should be developed to ensure the quality of the developed products. In another front, the persistent improvement in direct geo-referencing technology has led to an expansion in the use of LiDAR systems for the acquisition of dense and accurate surface information. However, the processing of the raw LiDAR data (e.g., ranges, mirror angles, and navigation data) remains a non-transparent process that is proprietary to the manufacturers of LiDAR systems. Therefore, the DPRG has been focusing on the development of quality control procedures to quantify the accuracy of LiDAR output in the absence of initial system measurements. This paper presents a summary of the research conducted by the DPRG together with the British Columbia Base Mapping and Geomatic Services (BMGS) and the United States Geological Survey (USGS) for the development of quality assurance and quality control procedures for emerging mapping technologies. The outcome of this research will allow for the possiblity of introducing North American Standards and Specifications to regulate the use of MFDC and LiDAR systems in the mapping industry.

EAARL Coastal Topography - Northeast Barrier Islands 2007: Bare Earth

USGS Publications Warehouse

Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Wright, C. Wayne; Yates, Xan; Bonisteel, Jamie M.

2008-01-01

These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the northeast coastal barrier islands in New York and New Jersey, acquired April 29-30 and May 15-16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

EAARL Topography - Natchez Trace Parkway 2007: First Surface

USGS Publications Warehouse

Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Segura, Martha; Yates, Xan

2008-01-01

These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Natchez Trace Parkway in Mississippi, acquired on September 14, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

EAARL Topography - Vicksburg National Military Park 2008: Bare Earth

USGS Publications Warehouse

Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Segura, Martha; Yates, Xan

2008-01-01

These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Vicksburg National Military Park in Mississippi, acquired on March 6, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

EAARL Coastal Topography - Northeast Barrier Islands 2007: First Surface

USGS Publications Warehouse

Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Wright, C. Wayne; Yates, Xan; Bonisteel, Jamie M.

2009-01-01

These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the northeast coastal barrier islands in New York and New Jersey, acquired April 29-30 and May 15-16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

EAARL Topography-Vicksburg National Military Park 2007: First Surface

USGS Publications Warehouse

Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Segura, Martha; Yates, Xan

2009-01-01

These remotely sensed, geographically referenced elevation measurements of Lidar-derived first-surface (FS) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Vicksburg National Military Park in Mississippi, acquired on September 12, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

EAARL Coastal Topography--Cape Canaveral, Florida, 2009: First Surface

USGS Publications Warehouse

Bonisteel-Cormier, J.M.; Nayegandhi, Amar; Plant, Nathaniel; Wright, C.W.; Nagle, D.B.; Serafin, K.S.; Klipp, E.S.

2011-01-01

These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography datasets were produced collaboratively by the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Kennedy Space Center, FL. This project provides highly detailed and accurate datasets of a portion of the eastern Florida coastline beachface, acquired on May 28, 2009. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color-infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine aircraft, but the instrument was deployed on a Pilatus PC-6. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or sub-aerial topography. Specialized filtering algorithms have been implemented to determine the "bare earth" under vegetation from a point cloud of last return elevations.

EAARL Coastal Topography - Sandy Hook 2007

USGS Publications Warehouse

Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Stevens, Sara; Yates, Xan; Bonisteel, Jamie M.

2008-01-01

These remotely sensed, geographically referenced elevation measurements of Lidar-derived topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Northeast Coastal and Barrier Network, Kingston, RI; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of Gateway National Recreation Area's Sandy Hook Unit in New Jersey, acquired on May 16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL) was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for pre-survey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography. Specialized filtering algorithms have been implemented to determine the 'bare earth' under vegetation from a point cloud of last return elevations.

Signal Processing and Calibration of Continuous-Wave Focused CO2 Doppler Lidars for Atmospheric Backscatter Measurement

NASA Technical Reports Server (NTRS)

Rothermel, Jeffry; Chambers, Diana M.; Jarzembski, Maurice A.; Srivastava, Vandana; Bowdle, David A.; Jones, William D.

1996-01-01

Two continuous-wave(CW)focused C02 Doppler lidars (9.1 and 10.6 micrometers) were developed for airborne in situ aerosol backscatter measurements. The complex path of reliably calibrating these systems, with different signal processors, for accurate derivation of atmospheric backscatter coefficients is documented. Lidar calibration for absolute backscatter measurement for both lidars is based on range response over the lidar sample volume, not solely at focus. Both lidars were calibrated with a new technique using well-characterized aerosols as radiometric standard targets and related to conventional hard-target calibration. A digital signal processor (DSP), a surface acoustic and spectrum analyzer and manually tuned spectrum analyzer signal analyzers were used. The DSP signals were analyzed with an innovative method of correcting for systematic noise fluctuation; the noise statistics exhibit the chi-square distribution predicted by theory. System parametric studies and detailed calibration improved the accuracy of conversion from the measured signal-to-noise ratio to absolute backscatter. The minimum backscatter sensitivity is approximately 3 x 10(exp -12)/m/sr at 9.1 micrometers and approximately 9 x 10(exp -12)/m/sr at 10.6 micrometers. Sample measurements are shown for a flight over the remote Pacific Ocean in 1990 as part of the NASA Global Backscatter Experiment (GLOBE) survey missions, the first time to our knowledge that 9.1-10.6 micrometer lidar intercomparisons were made. Measurements at 9.1 micrometers, a potential wavelength for space-based lidar remote-sensing applications, are to our knowledge the first based on the rare isotope C-12 O(2)-18 gas.

Finnish Meteorological Institute Doppler Lidar

DOE Data Explorer

Ewan OConnor

2015-03-27

This doppler lidar system provides co-polar and cross polar attenuated backscatter coefficients,signal strength, and doppler velocities in the cloud and in the boundary level, including uncertainties for all parameters. Using the doppler beam swinging DBS technique, and Vertical Azimuthal Display (VAD) this system also provides vertical profiles of horizontal winds.

Abu Dhabi Basemap Update Using the LiDAR Mobile Mapping Technology

NASA Astrophysics Data System (ADS)

Alshaiba, Omar; Amparo Núñez-Andrés, M.; Lantada, Nieves

2016-04-01

Mobile LiDAR system provides a new technology which can be used to update geospatial information by direct and rapid data collection. This technology is faster than the traditional survey ways and has lower cost. Abu Dhabi Municipal System aims to update its geospatial system frequently as the government entities have invested heavily in GIS technology and geospatial data to meet the repaid growth in the infrastructure and construction projects in recent years. The Emirate of Abu Dhabi has witnessed a huge growth in infrastructure and construction projects in recent years. Therefore, it is necessary to develop and update its basemap system frequently to meet their own organizational needs. Currently, the traditional ways are used to update basemap system such as human surveyors, GPS receivers and controller (GPS assigned computer). Then the surveyed data are downloaded, edited and reviewed manually before it is merged to the basemap system. Traditional surveying ways may not be applicable in some conditions such as; bad weather, difficult topographic area and boundary area. This paper presents a proposed methodology which uses the Mobile LiDAR system to update basemap in Abu Dhabi by using daily transactions services. It aims to use and integrate the mobile LiDAR technology into the municipality's daily workflow such that it becomes the new standard cost efficiency operating procedure for updating the base-map in Abu Dhabi Municipal System. On another note, the paper will demonstrate the results of the innovated workflow for the base-map update using the mobile LiDAR point cloud and few processing algorithms.

Estimating forest structural characteristics using the airborne LiDAR scanning system and a near-real time profiling laser system

NASA Astrophysics Data System (ADS)

Zhao, Kaiguang

LiDAR (Light Detection and Ranging) directly measures canopy vertical structures, and provides an effective remote sensing solution to accurate and spatially-explicit mapping of forest characteristics, such as canopy height and Leaf Area Index. However, many factors, such as large data volume and high costs for data acquisition, precludes the operational and practical use of most currently available LiDARs for frequent and large-scale mapping. At the same time, a growing need is arising for real-time remote sensing platforms, e.g., to provide timely information for urgent applications. This study aims to develop an airborne profiling LiDAR system, featured with on-the-fly data processing, for near real- or real-time forest inventory. The development of such a system involves implementing the on-board data processing and analysis as well as building useful regression-based models to relate LiDAR measurements with forest biophysical parameters. This work established a paradigm for an on-the-fly airborne profiling LiDAR system to inventory regional forest resources in real- or near real-time. The system was developed based on an existing portable airborne laser system (PALS) that has been previously assembled at NASA by Dr. Ross Nelson. Key issues in automating PALS as an on-the-fly system were addressed, including the design of an archetype for the system workflow, the development of efficient and robust algorithms for automatic data processing and analysis, the development of effective regression models to predict forest biophysical parameters from LiDAR measurements, and the implementation of an integrated software package to incorporate all the above development. This work exploited the untouched potential of airborne laser profilers for real-time forest inventory, and therefore, documented an initial step toward developing airborne-laser-based, on-the-fly, real-time, forest inventory systems. Results from this work demonstrated the utility and effectiveness of airborne scanning or profiling laser systems for remotely measuring various forest structural attributes at a range of scales, i.e., from individual tree, plot, stand and up to regional levels. The system not only provides a regional assessment tool, one that can be used to repeatedly, remotely measure hundreds or thousands of square kilometers with little/no analyst interaction or interpretation, but also serves as a paradigm for future efforts in building more advanced airborne laser systems such as real-time laser scanners.

Characterization of Upper Troposphere Water Vapor Measurements during AFWEX using LASE

NASA Technical Reports Server (NTRS)

Ferrare, R. A.; Browell, E. V.; Ismail, S.; Kooi, S.; Brasseur, L. H.; Brackett, V. G.; Clayton, M.; Barrick, J.; Linne, H.; Lammert, A.

2002-01-01

Water vapor profiles from NASA's Lidar Atmospheric Sensing Experiment (LASE) system acquired during the ARM/FIRE Water Vapor Experiment (AFWEX) are used to characterize upper troposphere water vapor (UTWV) measured by ground-based Raman lidars, radiosondes, and in situ aircraft sensors. Initial comparisons showed the average Vaisala radiosonde measurements to be 5-15% drier than the average LASE, Raman lidar, and DC-8 in situ diode laser hygrometer measurements. We show that corrections to the Raman lidar and Vaisala measurements significantly reduce these differences. Precipitable water vapor (PWV) derived from the LASE water vapor profiles agrees within 3% on average with PWV derived from the ARM ground-based microwave radiometer (MWR). The agreement among the LASE, Raman lidar, and MWR measurements demonstrates how the LASE measurements can be used to characterize both profile and column water vapor measurements and that ARM Raman lidar, when calibrated using the MWR PWV, can provide accurate UTWV measurements.

Lidar and Radar Measurements of the melting layer in the frame of the Convective and Orographically-induced Precipitation Study

NASA Astrophysics Data System (ADS)

Di Girolamo, Paolo; Summa, Donato; Bhawar, Rohini; Di Iorio, Tatiana; Vaughan, Geraint; Norton, Emily; Peters, Gerhard

2009-03-01

During the Convective and Orographically-induced Precipitation Study (COPS), lidar dark bands were observed by the Univ. of BASILicata Raman lidar system (BASIL) on several IOPs and SOPs (among others, 23 July, 15 August, 17 August). Dark band signatures appear in the lidar measurements of particle backscattering at 355, 532 and 1064 nm and particle extinction at 355 and 532 nm, as well as in particle depolarization measurements. Lidar data are supported by measurements from the University of Hamburg cloud radar MIRA 36 (36 GHz), the University of Hamburg dual-polarization micro rain radars (24.1 GHz) and the University of Manchester Radio UHF clear air wind profiler (1.29 GHz). Results from BASIL and the radars are illustrated and discussed to support in the comprehension of the microphysical and scattering processes responsible for the appearance of the lidar dark band and radar bright band.

Integrated remote sensing and visualization (IRSV) system for transportation infrastructure operations and management, phase two, volume 2 : applications of LiDAR technology in structural evaluation under normal traffic operation and post blast loading.

DOT National Transportation Integrated Search

2012-03-01

This report focused on two potential applications of terrestrial LiDAR scans on highway : bridges: 1) vehicle crossing effects measured by3-D, terrestrial LiDAR scans of highway bridges : measuring clearance distance; and 2) bridge post-blast geometr...

Three atmospheric dispersion experiments involving oil fog plumes measured by lidar

NASA Technical Reports Server (NTRS)

Eberhard, W. L.; Mcnice, G. T.; Troxel, S. W.

1986-01-01

The Wave Propagation Lab. participated with the U.S. Environmental Protection Agency in a series of experiments with the goal of developing and validating dispersion models that perform substantially better that models currently available. The lidar systems deployed and the data processing procedures used in these experiments are briefly described. Highlights are presented of conclusions drawn thus far from the lidar data.

Intelligent Behavioral Action Aiding for Improved Autonomous Image Navigation

DTIC Science & Technology

2012-09-13

odometry, SICK laser scanning unit ( Lidar ), Inertial Measurement Unit (IMU) and ultrasonic distance measurement system (Figure 32). The Lidar , IMU...2010, July) GPS world. [Online]. http://www.gpsworld.com/tech-talk- blog/gnss-independent-navigation-solution-using-integrated- lidar -data-11378 [4...Milford, David McKinnon, Michael Warren, Gordon Wyeth, and Ben Upcroft, "Feature-based Visual Odometry and Featureless Place Recognition for SLAM in

Mapping above- and below-ground carbon pools in boreal forests: The case for airborne lidar

Treesearch

Terje Kristensen; Erik Naesset; Mikael Ohlson; Paul V. Bolstad; Randall Kolka

2015-01-01

A large and growing body of evidence has demonstrated that airborne scanning light detection and ranging (lidar) systems can be an effective tool in measuring and monitoring above-ground forest tree biomass. However, the potential of lidar as an all-round tool for assisting in assessment of carbon (C) stocks in soil and non-tree vegetation components of the forest...

Two-day period fluctuation of PMC occurrence over Syowa Station, Antarctica observed by a ground-based lidar and AIM satellite.

NASA Astrophysics Data System (ADS)

Nakamura, T.; Suzuki, H.; Tsutsumi, M.; Ejiri, M. K.; Tomikawa, Y.; Abo, M.; Kawahara, T.; Tsuda, T. T.; Nishiyama, T.

2014-12-01

A Rayleigh/Raman lidar system has been operated by the Japanese Antarctic Research Expedition (JARE) since February, 2011 (JARE 52nd) in Syowa Station Antarctica (69.0S, 39.5E). The lidar system consists of a pulsed Nd:YAG laser (355nm) as a transmitter and two telescopes with four photo multiplier tubes which are to detect Rayleigh scattered light from low and high atmosphere at 355 nm and N2 Raman emission at 387nm. Polar Mesospheric Cloud (PMC) was detected by the lidar at 22:30UT (+3hr for LT) on Feb 4th, 2011, the first day of a routine operation. This event was the first time to detect PMC over Syowa Station by a lidar [Suzuki et al., Ann. Geophys., 2013]. However, signal to noise ratio (SNR) of the PMC event was not so good due to large shot noises from daytime background signals. Moreover, a receiver system was designed mainly for nighttime observations. In this way, observation of PMC during the midnight sun, which also corresponds to most frequent PMC season, was difficult. Thus, to improve SNR of the PMC observation with the lidar during daytime, a narrow band-pass Fabry-Perot etalon unit has been developed and installed in the receiver system on Dec 2013 by JARE 55th. By using this new system, clear PMC signals were successfully detected under daylight condition during the period of summer operation of JARE55th. During this period of 53 days (from 17 Dec. 2013 to 7 Feb. 2014), only 11 days were with a clear sky and suitable for PMC observation. Thus, it was difficult to study temporal variations on a PMC activity only by using the lidar data. Fortunately, NASA's AIM satellite had passed near Syowa Station and provided with complimentary PMC data during observation gap of the lidar. By combining our lidar data with the AIM/CIPS data, nearly continuous monitoring of PMC variability over Syowa Station was achieved for period between 13th and 18th in January 2014. PMC occurrence with an interval of two days over Syowa Station during the period was clearly confirmed. Co-located MF radar also showed clear two days fluctuation in horizontal wind velocities around PMC altitude during the same period. In this presentation, we will discuss the cause of the two-day oscillation found in PMC occurrence and horizontal wind velocity. In particular, two-day planetary wave will be quantitatively investigated as a potential cause of the fluctuation.

FLASH LIDAR Based Relative Navigation

NASA Technical Reports Server (NTRS)

Brazzel, Jack; Clark, Fred; Milenkovic, Zoran

2014-01-01

Relative navigation remains the most challenging part of spacecraft rendezvous and docking. In recent years, flash LIDARs, have been increasingly selected as the go-to sensors for proximity operations and docking. Flash LIDARS are generally lighter and require less power that scanning Lidars. Flash LIDARs do not have moving parts, and they are capable of tracking multiple targets as well as generating a 3D map of a given target. However, there are some significant drawbacks of Flash Lidars that must be resolved if their use is to be of long-term significance. Overcoming the challenges of Flash LIDARs for navigation-namely, low technology readiness level, lack of historical performance data, target identification, existence of false positives, and performance of vision processing algorithms as intermediaries between the raw sensor data and the Kalman filter-requires a world-class testing facility, such as the Lockheed Martin Space Operations Simulation Center (SOSC). Ground-based testing is a critical step for maturing the next-generation flash LIDAR-based spacecraft relative navigation. This paper will focus on the tests of an integrated relative navigation system conducted at the SOSC in January 2014. The intent of the tests was to characterize and then improve the performance of relative navigation, while addressing many of the flash LIDAR challenges mentioned above. A section on navigation performance and future recommendation completes the discussion.

Lidar observations of vertically organized convection in the planetary boundary layer over the ocean

NASA Technical Reports Server (NTRS)

Melfi, S. H.; Spinhirne, J. D.; Chou, S.-H.; Palm, S. P.

1985-01-01

Observations of a convective planetary boundary layer (PBL) were made with an airborne, downward-looking lidar system over the Atlantic Ocean during a cold air outbreak. The lidar data revealed well-organized, regularly spaced cellular convection with dominant spacial scales between two and four times the height of the boundary layer. It is demonstrated that the lidar can accurately measure the structure of the PBL with high vertical and horizontal resolution. Parameters important for PBL modeling such as entrainment zone thickness, entrainment rate, PBL height and relative heat flux can be inferred from the lidar data. It is suggested that wind shear at the PBL top may influence both entrainment and convective cell size.

Phoenix Lidar Operation Animation

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] Click on image for animation

This is an animation of the Canadian-built meteorological station's lidar, which was successfully activated on Sol 2. The animation shows how the lidar is activated by first opening its dust cover, then emitting rapid pulses of light (resembling a brilliant green laser) into the Martian atmosphere. Some of the light then bounces off particles in the atmosphere, and is reflected back down to the lidar's telescope. This allows the lidar to detect dust, clouds and fog.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Identification of aerosol composition from multi-wavelength lidar measurements

NASA Technical Reports Server (NTRS)

Wood, S. A.

1984-01-01

This paper seeks to develop the potential of lidar for the identification of the chemical composition of atmospheric aerosols. Available numerical computations suggest that aerosols can be identified by the wavelength dependence of aerosol optical properties. Since lidar can derive the volume backscatter coefficient as a function of wavelength, a multi-wavelength lidar system may be able to provide valuable information on the composition of aerosols. This research theoretically investigates the volume backscatter coefficients for the aerosol classes, sea-salts, and sulfates, as a function of wavelength. The results show that these aerosol compositions can be characterized and identified by their backscatter wavelength dependence. A method to utilize multi-wavelength lidar measurements to discriminate between compositionally different thin aerosol layers is discussed.

EAARL coastal topography--Alligator Point, Louisiana, 2010

USGS Publications Warehouse

Nayegandhi, Amar; Bonisteel-Cormier, J.M.; Wright, C.W.; Brock, J.C.; Nagle, D.B.; Vivekanandan, Saisudha; Fredericks, Xan; Barras, J.A.

2012-01-01

This project provides highly detailed and accurate datasets of a portion of Alligator Point, Louisiana, acquired on March 5 and 6, 2010. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the National Aeronautics and Space Administration (NASA) Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color-infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine aircraft, but the instrument was deployed on a Pilatus PC-6. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or sub-aerial topography. Specialized filtering algorithms have been implemented to determine the "bare earth" under vegetation from a point cloud of last return elevations.

Point Cloud Refinement with a Target-Free Intrinsic Calibration of a Mobile Multi-Beam LIDAR System

NASA Astrophysics Data System (ADS)

Nouiraa, H.; Deschaud, J. E.; Goulettea, F.

2016-06-01

LIDAR sensors are widely used in mobile mapping systems. The mobile mapping platforms allow to have fast acquisition in cities for example, which would take much longer with static mapping systems. The LIDAR sensors provide reliable and precise 3D information, which can be used in various applications: mapping of the environment; localization of objects; detection of changes. Also, with the recent developments, multi-beam LIDAR sensors have appeared, and are able to provide a high amount of data with a high level of detail. A mono-beam LIDAR sensor mounted on a mobile platform will have an extrinsic calibration to be done, so the data acquired and registered in the sensor reference frame can be represented in the body reference frame, modeling the mobile system. For a multibeam LIDAR sensor, we can separate its calibration into two distinct parts: on one hand, we have an extrinsic calibration, in common with mono-beam LIDAR sensors, which gives the transformation between the sensor cartesian reference frame and the body reference frame. On the other hand, there is an intrinsic calibration, which gives the relations between the beams of the multi-beam sensor. This calibration depends on a model given by the constructor, but the model can be non optimal, which would bring errors and noise into the acquired point clouds. In the litterature, some optimizations of the calibration parameters are proposed, but need a specific routine or environment, which can be constraining and time-consuming. In this article, we present an automatic method for improving the intrinsic calibration of a multi-beam LIDAR sensor, the Velodyne HDL-32E. The proposed approach does not need any calibration target, and only uses information from the acquired point clouds, which makes it simple and fast to use. Also, a corrected model for the Velodyne sensor is proposed. An energy function which penalizes points far from local planar surfaces is used to optimize the different proposed parameters for the corrected model, and we are able to give a confidence value for the calibration parameters found. Optimization results on both synthetic and real data are presented.

Quantification of LiDAR measurement uncertainty through propagation of errors due to sensor sub-systems and terrain morphology

NASA Astrophysics Data System (ADS)

Goulden, T.; Hopkinson, C.

2013-12-01

The quantification of LiDAR sensor measurement uncertainty is important for evaluating the quality of derived DEM products, compiling risk assessment of management decisions based from LiDAR information, and enhancing LiDAR mission planning capabilities. Current quality assurance estimates of LiDAR measurement uncertainty are limited to post-survey empirical assessments or vendor estimates from commercial literature. Empirical evidence can provide valuable information for the performance of the sensor in validated areas; however, it cannot characterize the spatial distribution of measurement uncertainty throughout the extensive coverage of typical LiDAR surveys. Vendor advertised error estimates are often restricted to strict and optimal survey conditions, resulting in idealized values. Numerical modeling of individual pulse uncertainty provides an alternative method for estimating LiDAR measurement uncertainty. LiDAR measurement uncertainty is theoretically assumed to fall into three distinct categories, 1) sensor sub-system errors, 2) terrain influences, and 3) vegetative influences. This research details the procedures for numerical modeling of measurement uncertainty from the sensor sub-system (GPS, IMU, laser scanner, laser ranger) and terrain influences. Results show that errors tend to increase as the laser scan angle, altitude or laser beam incidence angle increase. An experimental survey over a flat and paved runway site, performed with an Optech ALTM 3100 sensor, showed an increase in modeled vertical errors of 5 cm, at a nadir scan orientation, to 8 cm at scan edges; for an aircraft altitude of 1200 m and half scan angle of 15°. In a survey with the same sensor, at a highly sloped glacial basin site absent of vegetation, modeled vertical errors reached over 2 m. Validation of error models within the glacial environment, over three separate flight lines, respectively showed 100%, 85%, and 75% of elevation residuals fell below error predictions. Future work in LiDAR sensor measurement uncertainty must focus on the development of vegetative error models to create more robust error prediction algorithms. To achieve this objective, comprehensive empirical exploratory analysis is recommended to relate vegetative parameters to observed errors.

EARLINET Single Calculus Chain - overview on methodology and strategy

NASA Astrophysics Data System (ADS)

D'Amico, G.; Amodeo, A.; Baars, H.; Binietoglou, I.; Freudenthaler, V.; Mattis, I.; Wandinger, U.; Pappalardo, G.

2015-11-01

In this paper we describe the EARLINET Single Calculus Chain (SCC), a tool for the automatic analysis of lidar measurements. The development of this tool started in the framework of EARLINET-ASOS (European Aerosol Research Lidar Network - Advanced Sustainable Observation System); it was extended within ACTRIS (Aerosol, Clouds and Trace gases Research InfraStructure Network), and it is continuing within ACTRIS-2. The main idea was to develop a data processing chain that allows all EARLINET stations to retrieve, in a fully automatic way, the aerosol backscatter and extinction profiles starting from the raw lidar data of the lidar systems they operate. The calculus subsystem of the SCC is composed of two modules: a pre-processor module which handles the raw lidar data and corrects them for instrumental effects and an optical processing module for the retrieval of aerosol optical products from the pre-processed data. All input parameters needed to perform the lidar analysis are stored in a database to keep track of all changes which may occur for any EARLINET lidar system over the time. The two calculus modules are coordinated and synchronized by an additional module (daemon) which makes the whole analysis process fully automatic. The end user can interact with the SCC via a user-friendly web interface. All SCC modules are developed using open-source and freely available software packages. The final products retrieved by the SCC fulfill all requirements of the EARLINET quality assurance programs on both instrumental and algorithm levels. Moreover, the manpower needed to provide aerosol optical products is greatly reduced and thus the near-real-time availability of lidar data is improved. The high-quality of the SCC products is proven by the good agreement between the SCC analysis, and the corresponding independent manual retrievals. Finally, the ability of the SCC to provide high-quality aerosol optical products is demonstrated for an EARLINET intense observation period.

Atmospheric aerosol profiling with a bistatic imaging lidar system.

PubMed

Barnes, John E; Sharma, N C Parikh; Kaplan, Trevor B

2007-05-20

Atmospheric aerosols have been profiled using a simple, imaging, bistatic lidar system. A vertical laser beam is imaged onto a charge-coupled-device camera from the ground to the zenith with a wide-angle lens (CLidar). The altitudes are derived geometrically from the position of the camera and laser with submeter resolution near the ground. The system requires no overlap correction needed in monostatic lidar systems and needs a much smaller dynamic range. Nighttime measurements of both molecular and aerosol scattering were made at Mauna Loa Observatory. The CLidar aerosol total scatter compares very well with a nephelometer measuring at 10 m above the ground. The results build on earlier work that compared purely molecular scattered light to theory, and detail instrument improvements.

Sixteenth International Laser Radar Conference, Part 1

NASA Technical Reports Server (NTRS)

Mccormick, M. Patrick (Editor)

1992-01-01

This publication contains extended abstracts of papers presented at the 16th International Laser Radar Conference. One-hundred ninety-five papers were presented in both oral and poster sessions. The topics of the conference sessions were: (1) Mt. Pinatubo Volcanic Dust Layer Observations; (2) Global Change/Ozone Measurements; (3) GLOBE/LAWS/LITE; (4) Mesospheric Measurements and Measurement Systems; (5) Middle Atmosphere; (6) Wind Measurements and Measurement Systems; (7) Imaging and Ranging; (8) Water Vapor Measurements; (9) Systems and Facilities; and (10) Laser Devices and Technology. This conference reflects the breadth of research activities being conducted in the lidar field. These abstracts address subjects from lidar-based atmospheric investigations relating to global change to the development of new lidar systems and technology.

Increasing the Impact of High-Resolution Lidar Topography Through Online Data Access and Processing

NASA Astrophysics Data System (ADS)

Crosby, C. J.; Nandigam, V.; Baru, C.; Arrowsmith, R.

2013-12-01

Topography data acquired with lidar (light detection and ranging) technology are revolutionizing the way we study the Earth's surface and overlying vegetation. These data, collected from satellite, airborne, tripod, or mobile-mounted scanners have emerged as a fundamental tool for research on topics including earthquake hazards, hillslope processes, and cyrosphere change. The U.S. National Science Foundation-funded OpenTopography (OT) Facility (http://www.opentopography.org) is a web-based system designed to democratize access to earth science-oriented lidar topography data. OT provides free, online access to lidar data in a number of forms, including the point cloud and associated geospatial-processing tools for customized analysis. The point cloud data are co-located with on-demand processing tools to generate digital elevation models, and derived products and visualizations which allow users to quickly access data in a format appropriate for their scientific application. The OT system is built using a service-oriented architecture (SOA) that leverages cyberinfrastructure resources at the San Diego Supercomputer Center at the University of California San Diego to allow users, regardless of expertise, to access these massive lidar datasets and derived raster data products for use in research and teaching. OT hosts over 600 billion lidar returns covering more than 120,000 km2. These data are provided by a variety of partners under joint agreements and memoranda of understanding with OT. Partners include national facilities such as the NSF-funded National Center for Airborne Lidar Mapping (NCALM), as well as non-governmental organizations and local, state, and federal agencies. OT has become a hub for high-resolution topography resources. Datasets hosted by other organizations, as well as lidar-specific software, can be registered into the OT catalog, providing users a 'one-stop shop' for such information. OT is also a partner on the NASA Lidar Access System (NLAS) project, collaborative research funded by the NASA ACCESS program, that makes NASA airborne and space based laser altimetry data (GLAS and LVIS) available through OT using federated web services. With several thousand active users, OT is an excellent example of a cyberinfrastructure-based airborne science data system that is enabling access to challenging data for research, education and outreach. OT has demonstrated that by democratizing access to lidar topography, the impact of these expensive research datasets is greatly increased, through reused in research, education, and commercial applications beyond their original scope. This presentation will highlight the OT system and lessons learned during its development. We will also highlight ongoing work related to creation of a more flexible and scalable high-performance environment for processing of large datasets; creation of a 'pluggable' infrastructure for third-party programs and algorithms to be run against the OT data holdings; and interoperability of OT with other earth science data systems.

Coherent Doppler Laser Radar: Technology Development and Applications

NASA Technical Reports Server (NTRS)

Kavaya, Michael J.; Arnold, James E. (Technical Monitor)

2000-01-01

NASA's Marshall Space Flight Center has been investigating, developing, and applying coherent Doppler laser radar technology for over 30 years. These efforts have included the first wind measurement in 1967, the first airborne flights in 1972, the first airborne wind field mapping in 1981, and the first measurement of hurricane eyewall winds in 1998. A parallel effort at MSFC since 1982 has been the study, modeling and technology development for a space-based global wind measurement system. These endeavors to date have resulted in compact, robust, eyesafe lidars at 2 micron wavelength based on solid-state laser technology; in a factor of 6 volume reduction in near diffraction limited, space-qualifiable telescopes; in sophisticated airborne scanners with full platform motion subtraction; in local oscillator lasers capable of rapid tuning of 25 GHz for removal of relative laser radar to target velocities over a 25 km/s range; in performance prediction theory and simulations that have been validated experimentally; and in extensive field campaign experience. We have also begun efforts to dramatically improve the fundamental photon efficiency of the laser radar, to demonstrate advanced lower mass laser radar telescopes and scanners; to develop laser and laser radar system alignment maintenance technologies; and to greatly improve the electrical efficiency, cooling technique, and robustness of the pulsed laser. This coherent Doppler laser radar technology is suitable for high resolution, high accuracy wind mapping; for aerosol and cloud measurement; for Differential Absorption Lidar (DIAL) measurements of atmospheric and trace gases; for hard target range and velocity measurement; and for hard target vibration spectra measurement. It is also suitable for a number of aircraft operations applications such as clear air turbulence (CAT) detection; dangerous wind shear (microburst) detection; airspeed, angle of attack, and sideslip measurement; and fuel savings through headwind minimization. In addition to the airborne and space platforms, a coherent Doppler laser radar system in an unmanned aerial vehicle (UAV) could provide battlefield weather and target identification.

ATM Coastal Topography - Louisiana, 2001: UTM Zone 16 (Part 2 of 2)

USGS Publications Warehouse

Yates, Xan; Nayegandhi, Amar; Brock, John C.; Sallenger, Asbury H.; Klipp, Emily S.; Wright, C. Wayne

2009-01-01

These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Louisiana coastline beach face within UTM Zone 16, from Grand Isle to the Chandeleur Islands, acquired September 7 and 9, 2001. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative scanning lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first-surface topography.

ATM Coastal Topography-Louisiana, 2001: UTM Zone 15 (Part 1 of 2)

USGS Publications Warehouse

Yates, Xan; Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Klipp, Emily S.; Wright, C. Wayne

2010-01-01

These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Louisiana coastline beach face within UTM Zone 15, from Isles Dernieres to Grand Isle, acquired September 7 and 10, 2001. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative scanning lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first-surface topography.

ATM Coastal Topography-Texas, 2001: UTM Zone 14

USGS Publications Warehouse

Klipp, Emily S.; Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Yates, Xan; Wright, C. Wayne

2009-01-01

These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Texas coastline within UTM zone 14, acquired October 12-13, 2001. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative scanning lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first-surface topography.

ATM Coastal Topography-Texas, 2001: UTM Zone 15

USGS Publications Warehouse

Klipp, Emily S.; Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Yates, Xan; Wright, C. Wayne

2009-01-01

These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Texas coastline within UTM zone 15, from Matagorda Peninsula to Galveston Island, acquired October 12-13, 2001. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative scanning lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first-surface topography.

ATM Coastal Topography-Florida 2001: Western Panhandle

USGS Publications Warehouse

Yates, Xan; Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Klipp, Emily S.; Wright, C. Wayne

2009-01-01

These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the western Florida panhandle coastline, acquired October 2-4 and 7-10, 2001. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative scanning Lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning Lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for presurvey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography.

ATM Coastal Topography-Mississippi, 2001

USGS Publications Warehouse

Nayegandhi, Amar; Yates, Xan; Brock, John C.; Sallenger, A.H.; Klipp, Emily S.; Wright, C. Wayne

2009-01-01

These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Mississippi coastline, from Lakeshore to Petit Bois Island, acquired September 9-10, 2001. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative scanning lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is used routinely to create maps that represent submerged or first-surface topography.

Optimization design of the tuning method for FBG spectroscopy based on the numerical analysis of all-fiber Raman temperature lidar

NASA Astrophysics Data System (ADS)

Wang, Li; Wang, Jun; Bao, Dong; Yang, Rong; Yan, Qing; Gao, Fei; Hua, Dengxin

2018-01-01

All fiber Raman temperature lidar for space borne platform has been proposed for profiling of the temperature with high accuracy. Fiber Bragg grating (FBG) is proposed as the spectroscopic system of Raman lidar because of good wavelength selectivity, high spectral resolution and high out-of-band rejection rate. Two sets of FBGs at visible wavelength 532 nm as Raman spectroscopy system are designed for extracting the rotational Raman spectra of atmospheric molecules, which intensities depend on the atmospheric temperature. The optimization design of the tuning method of an all-fiber rotational Raman spectroscopy system is analyzed and tested for estimating the potential temperature inversion error caused by the instability of FBG. The cantilever structure with temperature control device is designed to realize the tuning and stabilization of the central wavelengths of FBGs. According to numerical calculation of FBG and finite element analysis of the cantilever structure, the center wavelength offset of FBG is 11.03 nm/°C with the temperature change in the spectroscopy system. By experimental observation, the center wavelength offset of surface-bonded FBG is 9.80 nm/°C with temperature changing when subjected to certain strain for the high quantum number channel, while 10.01 nm/°C for the low quantum number channel. The tunable wavelength range of FBG is from 528.707 nm to 529.014 nm for the high quantum number channel and from 530.226 nm to 530.547 nm for the low quantum number channel. The temperature control accuracy of the FBG spectroscopy system is up to 0.03 °C, the corresponding potential atmospheric temperature inversion error is 0.04 K based on the numerical analysis of all-fiber Raman temperature lidar. The fine tuning and stabilization of the FBG wavelength realize the elaborate spectroscope of Raman lidar system. The conclusion is of great significance for the application of FBG spectroscopy system for space-borne platform Raman lidar.

A Fiber-Optic Coupled Telescope for Water Vapor DIAL Receivers

NASA Technical Reports Server (NTRS)

DeYoung, Russell J.; Lonn, Frederick

1998-01-01

A fiber-optic coupled telescope of low complexity was constructed and tested. The major loss mechanisms of the optical system have been characterized. Light collected by the receiver mirror is focused onto an optical fiber, and the output of the fiber is filtered by an interference filter and then focused onto an APD detector. This system was used in lidar field measurements with a 532-nm Nd:YAG laser beam. The results were encouraging. A numerical model used for calculation of the expected return signal agreed with the lidar return signal obtained. The assembled system was easy to align and operate and weighed about 8 kg for a 30 cm (12") mirror system. This weight is low enough to allow mounting of the fiber-optic telescope receiver system in a UAV. Furthermore, the good agreement between the numerical lidar model and the performance of the actual receiver system, suggests that this model may be used for estimation of the performance of this and other lidar systems in the future. Such telescopes are relatively easy to construct and align. The fiber optic cable allows easy placement of the optical detector in any position. These telescope systems should find widespread use in aircraft and space home DIAL water vapor receiver systems.

Landslide stability analysis on basis of LIDAR data extraction

NASA Astrophysics Data System (ADS)

Hu, Hui; Fernandez-Steeger, Tomas M.; Dong, Mei; Azzam, Rafig

2010-05-01

Currently, existing contradictory between remediation and acquisition from natural resource induces a series of divergences. With regard to open pit mining, legal regulation requires human to fill back the open pit area with water or recreate new landscape by other materials; on the other hand, human can not help excavating the mining area due to the shortage of power resource. However, to engineering geologists, one coincident problem which takes place not only in filling but also in mining operation should be paid more attention to, i.e. the slope stability analysis within these areas. There are a number of construction activities during remediation or mining process which can directly or indirectly cause slope failure. Lives can be endangered since local failure either while or after remediation; for mining process, slope failure in a bench, which carries a main haul road or is adjacent to human activity area, would be significant catastrophe to the whole mining program. The stability of an individual bench or slope is controlled by several factors, which are geological condition, morphology, climate, excavation techniques and transportation approach. The task which takes the longest time is to collect the morphological data. Consequently, it is one of the most dangerous tasks due to the time consuming in mining field. LIDAR scanning for morphological data collecting can help to skip this obstacle since advantages of LIDAR techniques as follows: • Dynamic range available on the market: from 3 m to beyond 1 km, • Ruggedly designed for demanding field applications, • Compact, easily hand-carried and deployed by a single operator. In 2009, scanning campaigns for 2 open pit quarry have been carried out. The aim for these LIDAR detections is to construct a detailed 3D quarry model and analyze the bench stability to support the filling planning. The 3D quarry surface was built up by using PolyWorks 10.1 on basis of LIDAR data. LIDAR data refining takes an important role during surface construction for further more precise analysis purpose. 3D geological model can be built based on the connection between surface model and geological data like borehole data in GOCAD. Regarding the bench stability analysis, LEM (Limit Equilibrium Method) analysis using Janbu and FEM (Finite Element Method) have been adopted during this analyzing task. A program was developed to convert GOCAD 2D section data directly into the FEM software. The meshed model is then used for stability analysis. In one quarry, 3 cross sections have been extracted on basis of LIDAR original data (original 3 cross sections). To evaluate the advantages of LIDAR data for slope analysis, the results of safety factor (SF) were compared to simplified slope models as they are used normally. The comparison showed that variations of the SF reach up to 9%. Additionally, conservative evaluation demonstrated by SF results based on simplified model is not adaptive for decision making of filling.

Raman Lidar Measurements of Aerosol Optical Properties Performed at CNR- IMAA

NASA Astrophysics Data System (ADS)

Mona, L.; Amodeo, A.; Cornacchia, C.; D'Amico, G.; Madonna, F.; Pandolfi, M.; Pappalardo, G.

2005-12-01

The lidar system for tropospheric aerosol study, located at CNR-IMAA in Tito Scalo, Potenza (40 °36'N, 15°44' E, 760 m above sea level), is a Raman/elastic lidar system operational since May 2000 in the framework of EARLINET (European Aerosol Research LIdar NETwork), the first lidar network for tropospheric aerosol study on continental scale. It provides independent measurements of aerosol extinction and backscatter coefficient profiles at 355 nm and aerosol backscatter profiles at 532 nm. Both the IMAA aerosol lidar system and the used algorithms for the retrieval of aerosol optical parameters have been successfully tested with different intercomparison exercises in the frame of the EARLINET quality assurance program. In the frame of EARLINET, regular measurements are performed three times per week, allowing to study the aerosol content typically present in the planetary boundary layer over Potenza. Particular attention is devoted to Saharan dust intrusions in Europe, and Saharan dust forecasts are distributed to all EARLINET stations. The large dataset of Saharan dust optical properties profiles collected at IMAA allowed to study the contribution of dust particles to the aerosol load typically present in our area as well as to investigate transformations of aerosol optical properties during the transport. Several intensive measurement campaigns have been performed at IMAA with this system to study optical properties of different types of aerosol, and how the transport and modification mechanisms and the water content affect these optical properties. In particular, direct transport of volcanic aerosol emitted in 2002 during the Etna eruptions was observed, and in summer 2004, aerosol layers related to forest fires smoke or pollution plume transported from Alaska, Canada and North America were observed at IMAA during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) field campaign. Moreover, this system has been used during the Italian phase of the European AQUA Thermodynamic Experiment (EAQUATE) measurements campaign (6-10 September 2005) together with a water vapor Raman lidar for an integrated study of aerosol, water vapor and clouds. In order to obtain more information about microphysical properties of the particles, the IMAA lidar system for aerosol has been upgraded to increase the number of retrievable parameters. In particular, since July 2005, this system can provide independent measurements of aerosol extinction and backscatter profiles at 355 and 532 nm, and of aerosol backscatter profiles at 1064 nm. Moreover, other receiving channels were added to perform depolarization ratio measurements in order to obtain information about shape and orientation of aerosolic particles. Starting from October 2005, this upgraded system will be employed in the validation program of aerosol data products from the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) satellite mission. ACKNOWLEDGMENTS The support of this work by the European Commission under grant EVRI-CT1999-40003 is gratefully acknowledged. The CNR-IMAA ground based facility for Earth Observation has been partly funded by PON 2000-2006, Misura II.1, MIUR.

Lidar Wavelength Considerations and Radiometric Performance Analysis for Coastal Applications

NASA Astrophysics Data System (ADS)

Parrish, C. E.; Osiri, R.

2011-12-01

Until recently, the vast majority of commercial, topographic lidar systems operating in North America used 1064 nm lasers. However, systems employing erbium-doped fiber lasers operating at 1550 nm are becoming increasingly prevalent. An advantage of this wavelength is enhanced eye safety, as greater water absorption in the ocular components at wavelengths above ~1400 nm prevents radiation from reaching the retina. However, for related reasons, 1550 nm lidar systems may be subject to a greater decrease in signal-to-noise ratio (SNR) when the ground surface is wet. When operating near the upper limits of the system's operational altitude range-as is often done in order to maximize acquisition efficiency and minimize costs-this reduced SNR can lead to drop-outs and data gaps. The U.S. National Geodetic Survey (NGS), a program office of the National Oceanic and Atmospheric Administration (NOAA), uses lidar for coastal mapping applications. One of the primary goals is to extract tide-datum based shoreline, which is used in updating nautical charts, defining legal boundaries, and in a variety of coastal science and geomorphology studies. Mapping a tidally-referenced shoreline from topographic lidar data typically involves acquiring the data over exposed areas of the intertidal zone at low tide. Even when not submerged, these areas are frequently wet from the receding tide, wave runup, etc. If not compensated for through appropriate flight planning, the additional decrease in SNR with 1550 nm systems, due to the surface being wet, can lead to sparse, noisy data or even data voids, affecting the ability to extract a tidally-referenced shoreline. This study focuses on a theoretical and empirical investigation of 1550 nm lidar systems for coastal mapping. Lidar data were acquired over Assateague Island, Maryland with a new, dual Riegl LMS-Q680i system at a variety of flying heights. Additionally, reflectance spectra were acquired with a field spectrometer for various East Coast shorelines under differing moisture conditions, including dry, wet, and snow or ice covered. These data were used to quantify the effects on received signal strength and output data, and in determining how to best compensate for reduced SNR through proper selection of flying height and other mission parameters. We conclude with recommendations for effective and efficient operational use of 1550 nm systems for coastal applications.

A mobile system for active otpical pollution monitoring

NASA Technical Reports Server (NTRS)

Sunesson, A.; Edner, H.; Svanberg, S.; Uneus, L.; Wendt, W.; Fredriksson, K.

1986-01-01

The remote monitoring of atmospheric pollutants can now be performed in several ways. Laser radar techniques have proven their ability to reveal the spatial distribution of different species or particles. Classical optical techniques can also be used, but yield the average concentration over a given path and hence no range resolution. One such technique is Differential Optical Absorption Spectroscopy, DOAS. Such schemes can be used to monitor paths that a preliminary lidar investigation has shown to be of interest. Having previously had access to a mobile lidar system, a new system has been completed. The construction builds on experience from using the other system and it is meant to be more of a mobile optical laboratory than just a lidar system. A complete system description is given along with some preliminary usage. Future uses are contemplated.

Lidar network observation of dust layer evolution over the Gobi Desert in MAY 2013

NASA Astrophysics Data System (ADS)

Kawai, Kei; Kai, Kenji; Jin, Yoshitaka; Sugimoto, Nobuo; Batdorj, Dashdondog

2018-04-01

A lidar network captured the evolution of a dust layer in the Gobi Desert on 22-23 May 2013. The lidar network consists of a ceilometer and two AD-Net lidars in Mongolia. The dust layer was generated by a strong wind due to a cold front and elevated over the surface of the cold front by an updraft of the warm air in the cold-front system. It was evolving from the atmospheric boundary layer to the free troposphere while moving 600 km through the desert with the cold front.

Wind Profiles Obtained with a Molecular Direct Detection Doppler Lidar During IHOP-2002

NASA Technical Reports Server (NTRS)

Gentry, Bruce M.; Chen, Huai-Lin; Li, Steven X.; Mathur, Savyasachee; Dobler, Jeremy; Hasselbrack, William; Comer, Joseph

2004-01-01

The Goddard Lidar Observatory for Winds (GLOW) is a mobile direct detection Doppler lidar system which uses the double edge technique to measure the Doppler shift of the molecular backscattered laser signal at a wavelength of 355 nm. In the spring of 2002 GLOW was deployed to the western Oklahoma profiling site (36 deg 33.500 min. N, 100 deg. 36.371 min. W) to participate in the International H2O Project (IHOP). During the IHOP campaign over 240 hours of wind profiles were obtained with the GLOW lidar in support of a variety of scientific investigations.