Science.gov

Sample records for airborne radar systems

  1. Airborne rain mapping radar

    NASA Technical Reports Server (NTRS)

    Wilson, W. J.; Parks, G. S.; Li, F. K.; Im, K. E.; Howard, R. J.

    1988-01-01

    An airborne scanning radar system for remote rain mapping is described. The airborne rain mapping radar is composed of two radar frequency channels at 13.8 and 24.1 GHz. The radar is proposed to scan its antenna beam over + or - 20 deg from the antenna boresight; have a swath width of 7 km; a horizontal spatial resolution at nadir of about 500 m; and a range resolution of 120 m. The radar is designed to be applicable for retrieving rainfall rates from 0.1-60 mm/hr at the earth's surface, and for measuring linear polarization signatures and raindrop's fall velocity.

  2. The NASA Airborne Synthetic Aperture Radar System

    NASA Technical Reports Server (NTRS)

    Lou, Yunling; Kim, Yunjin; van Zyl, Jakob

    1996-01-01

    None given. (From introduction): ...we will briefly describe the instrument characteristics, the evolution of the various radar modes, the instrument performance and improvement in the knowledge of the positioning and attitude information of the radar. In addition, we will summarize the [rogress of the data processing effort, especially in the interferometry processing. Finally, we will address the issue of processing and calibrating the cross-track interferometry (XTI) data.

  3. The NASA/JPL Airborne Synthetic Aperture Radar System

    NASA Technical Reports Server (NTRS)

    Lou, Yunling; Kim,Yunjin; vanZyl, Jakob

    1996-01-01

    In this paper we will briefly describe the instrument characteristics, the evolution of various radar modes, the instrument performance and improvement in the knowledge of the positioning and attitude information of the NASA/JPL airborne synthetic aperture radar (SAR). This system operates in the fully polarimetric mode in the P, L, and C band simultaneously or in the interferometric mode in both the L and C band simultaneously. We also summarize the progress of the data processing effort, especially in the interferometry processing and we address the issue of processing and calibrating the cross-track interferometry data.

  4. The NASA/JPL Airborne Synthetic Aperture Radar System

    NASA Technical Reports Server (NTRS)

    Kim, Yun-Jin; Lou, Yun-Ling; vanZyl, Jakob

    1996-01-01

    The NASA/JPL airborne SAR (AIRSAR) system operates in the fully polarimetric mode at P-, L- and C-band simultaneously or in the interferometric mode in both L- and C-band simultaneously. The system became operational in late 1987 and flew its first mission aboard a DC-8 aircraft operated by NASA's Ames Research Center in Mountain View, California. Since then, the AIRSAR has flown missions every year and acquired images in North, Central and South America, Europe and Australia. In this paper, we will briefly describe the instrument characteristics, the evolution of the various radar modes, the instrument performance, and improvement in the knowledge of the positioning and attitude information of the radar. In addition, we will summarize the progress of the data processing effort especially in the interferometry processing. Finally, we will address the issue of processing and calibrating the cross-track interferometry (XTI) data.

  5. MARA (Multimode Airborne Radar Altimeter) system documentation. Volume 1: MARA system requirements document

    NASA Technical Reports Server (NTRS)

    Parsons, C. L. (Editor)

    1989-01-01

    The Multimode Airborne Radar Altimeter (MARA), a flexible airborne radar remote sensing facility developed by NASA's Goddard Space Flight Center, is discussed. This volume describes the scientific justification for the development of the instrument and the translation of these scientific requirements into instrument design goals. Values for key instrument parameters are derived to accommodate these goals, and simulations and analytical models are used to estimate the developed system's performance.

  6. Charge-coupled device data processor for an airborne imaging radar system

    NASA Technical Reports Server (NTRS)

    Arens, W. E. (Inventor)

    1977-01-01

    Processing of raw analog echo data from synthetic aperture radar receiver into images on board an airborne radar platform is discussed. Processing is made feasible by utilizing charge-coupled devices (CCD). CCD circuits are utilized to perform input sampling, presumming, range correlation and azimuth correlation in the analog domain. These radar data processing functions are implemented for single-look or multiple-look imaging radar systems.

  7. Dual-Frequency Airborne Scanning Rain Radar Antenna System

    NASA Technical Reports Server (NTRS)

    Hussein, Ziad A.; Green, Ken

    2004-01-01

    A compact, dual-frequency, dual-polarization, wide-angle-scanning antenna system has been developed as part of an airborne instrument for measuring rainfall. This system is an upgraded version of a prior single-frequency airborne rain radar antenna system and was designed to satisfy stringent requirements. One particularly stringent combination of requirements is to generate two dual-polarization (horizontal and vertical polarizations) beams at both frequencies (13.405 and 35.605 GHz) in such a way that the beams radiated from the antenna point in the same direction, have 3-dB angular widths that match within 25 percent, and have low sidelobe levels over a wide scan angle at each polarization-and-frequency combination. In addition, the system is required to exhibit low voltage standing-wave ratios at both frequencies. The system (see figure) includes a flat elliptical scanning reflector and a stationary offset paraboloidal reflector illuminated by a common-aperture feed system that comprises a corrugated horn with four input ports one port for each of the four frequency-and-polarization combinations. The feed horn is designed to simultaneously (1) under-illuminate the reflectors 35.605 GHz and (2) illuminate the reflectors with a 15-dB edge taper at 13.405 GHz. The scanning mirror is rotated in azimuth to scan the antenna beam over an angular range of 20 in the cross-track direction for wide swath coverage, and in elevation to compensate for the motion of the aircraft. The design of common-aperture feed horn makes it possible to obtain the required absolute gain and low side-lobe levels in wide-angle beam scanning. The combination of the common-aperture feed horn with the small (0.3) focal-length-to-diameter ratio of the paraboloidal reflector makes it possible for the overall system to be compact enough that it can be mounted on a DC-8 airplane.

  8. Performance of the NASA Airborne Radar with the Windshear Database for Forward-Looking Systems

    NASA Technical Reports Server (NTRS)

    Switzer, George F.; Britt, Charles L.

    1996-01-01

    This document describes the simulation approach used to test the performance of the NASA airborne windshear radar. An explanation of the actual radar hardware and processing algorithms provides an understanding of the parameters used in the simulation program. This report also contains a brief overview of the NASA airborne windshear radar experimental flight test results. A description of the radar simulation program shows the capabilities of the program and the techniques used for certification evaluation. Simulation of the NASA radar is comprised of three steps. First, the choice of the ground clutter data must be made. The ground clutter is the return from objects in or nearby an airport facility. The choice of the ground clutter also dictates the aircraft flight path since ground clutter is gathered while in flight. The second step is the choice of the radar parameters and the running of the simulation program which properly combines the ground clutter data with simulated windshear weather data. The simulated windshear weather data is comprised of a number of Terminal Area Simulation System (TASS) model results. The final step is the comparison of the radar simulation results to the known windshear data base. The final evaluation of the radar simulation is based on the ability to detect hazardous windshear with the aircraft at a safe distance while at the same time not displaying false alerts.

  9. Comparative study of tracking performance in an airborne tracking radar simulator using global positioning system versus monopulse radar techniques

    NASA Astrophysics Data System (ADS)

    Nguyen, Joseph H.; Holley, William D.; Gagnon, Garry

    1993-10-01

    This paper attempts to address the tracking accuracy between the two systems under test. A monopulse radar model was developed to theoretically calculate the would-be measured angle and angle variances. Essentially, measurements of the target's angle, angle variances, range and range rate from the monopulse radar receiver of an aircraft are assessed against the tracking performance of an airborne simulator which uses the time, space, position information (TSPI) delivered from a global positioning system (GPS) system. The accuracy of measurements from a monopulse radar primarily depends on the signal-to-noise ratio (SNR), distance from target in this case, but information received from the GPS Space Vehicle would be virtually jamfree, and independent of distance. Tracking using GPS data however requires good data link between airborne participants. The simulation fidelity becomes an issue when the target is in close range track. The monopulse random slope error and target glint become significant, while the resolution from GPS data links remains the same.

  10. ARMAR: An airborne rain-mapping radar

    NASA Technical Reports Server (NTRS)

    Durden, S. L.; Im, E.; Li, F. K.; Ricketts, W.; Tanner, A.; Wilson, W.

    1994-01-01

    A new airborne rain-mapping radar (ARMAR) has been developed by NASA and the Jet Propulsion Laboratory for operation on the NASA Ames DC-8 aircraft. The radar operates at 13.8 GHz, the frequency to be used by the radar on the Tropical Rainfall Measuring Mission (TRMM). ARMAR simulates the TRMM radar geometry by looking downward and scanning its antenna in the cross-track direction. This basic compatibility between ARMAR and TRMM allows ARMAR to provide information useful for the TRMM radar design, for rain retrieval algorithm development, and for postlaunch calibration. ARMAR has additional capabilities, including multiple polarization, Doppler velocity measurement, and a radiometer channel for brightness temperature measurement. The system has been tested in both ground-based and airborne configurations. This paper describes the design of the system and shows results of field tests.

  11. An application of space-time adaptive processing to airborne and spaceborne monostatic and bistatic radar systems

    NASA Astrophysics Data System (ADS)

    Czernik, Richard James

    A challenging problem faced by Ground Moving Target Indicator (GMTI) radars on both airborne and spaceborne platforms is the ability to detect slow moving targets due the presence of non-stationary and heterogeneous ground clutter returns. Space-Time Adaptive Processing techniques process both the spatial signals from an antenna array as well as radar pulses simultaneously to aid in mitigating this clutter which has an inherent Doppler shift due to radar platform motion, as well as spreading across Angle-Doppler space attributable to a variety of factors. Additional problems such as clutter aliasing, widening of the clutter notch, and range dependency add additional complexity when the radar is bistatic in nature, and vary significantly as the bistatic radar geometry changes with respect to the targeted location. The most difficult situation is that of a spaceborne radar system due to its high velocity and altitude with respect to the earth. A spaceborne system does however offer several advantages over an airborne system, such as the ability to cover wide areas and to provide access to areas denied to airborne platforms. This dissertation examines both monostatic and bistatic radar performance based upon a computer simulation developed by the author, and explores the use of both optimal STAP and reduced dimension STAP architectures to mitigate the modeled clutter returns. Factors such as broadband jamming, wind, and earth rotation are considered, along with their impact on the interference covariance matrix, constructed from sample training data. Calculation of the covariance matrix in near real time based upon extracted training data is computer processor intensive and reduced dimension STAP architectures relieve some of the computation burden. The problems resulting from extending both monostatic and bistatic radar systems to space are also simulated and studied.

  12. Removing interfering clutter associated with radar pulses that an airborne radar receives from a radar transponder

    DOEpatents

    Ormesher, Richard C.; Axline, Robert M.

    2008-12-02

    Interfering clutter in radar pulses received by an airborne radar system from a radar transponder can be suppressed by developing a representation of the incoming echo-voltage time-series that permits the clutter associated with predetermined parts of the time-series to be estimated. These estimates can be used to estimate and suppress the clutter associated with other parts of the time-series.

  13. The Utility and Validity of Kinematic GPS Positioning for the Geosar Airborne Terrain Mapping Radar System

    NASA Technical Reports Server (NTRS)

    Freedman, Adam; Hensley, Scott; Chapin, Elaine; Kroger, Peter; Hussain, Mushtaq; Allred, Bruce

    1999-01-01

    GeoSAR is an airborne, interferometric Synthetic Aperture Radar (IFSAR) system for terrain mapping, currently under development by a consortium including NASA's Jet Propulsion Laboratory (JPL), Calgis, Inc., a California mapping sciences company, and the California Department of Conservation (CaIDOC), with funding provided by the U.S. Army Corps of Engineers Topographic Engineering Center (TEC) and the U.S. Defense Advanced Research Projects Agency (DARPA). IFSAR data processing requires high-accuracy platform position and attitude knowledge. On 9 GeoSAR, these are provided by one or two Honeywell Embedded GPS Inertial Navigation Units (EGI) and an Ashtech Z12 GPS receiver. The EGIs provide real-time high-accuracy attitude and moderate-accuracy position data, while the Ashtech data, post-processed differentially with data from a nearby ground station using Ashtech PNAV software, provide high-accuracy differential GPS positions. These data are optimally combined using a Kalman filter within the GeoSAR motion measurement software, and the resultant position and orientation information are used to process the dual frequency (X-band and P-band) radar data to generate high-accuracy, high -resolution terrain imagery and digital elevation models (DEMs). GeoSAR requirements specify sub-meter level planimetric and vertical accuracies for the resultant DEMS. To achieve this, platform positioning errors well below one meter are needed. The goal of GeoSAR is to obtain 25 cm or better 3-D positions from the GPS systems on board the aircraft. By imaging a set of known point target corner-cube reflectors, the GeoSAR system can be calibrated. This calibration process yields the true position of the aircraft with an uncertainty of 20- 50 cm. This process thus allows an independent assessment of the accuracy of our GPS-based positioning systems. We will present an overview of the GeoSAR motion measurement system, focusing on the use of GPS and the blending of position data from the

  14. A survey of airborne radar systems for deployment on a High Altitude Powered Platform (HAPP)

    NASA Technical Reports Server (NTRS)

    Choudhury, B. J.; Leung, K. C.

    1979-01-01

    A survey was conducted to find out the system characteristics of commercially available and unclassified military radars suitable for deployment on a stationary platform. A total of ten domestic and eight foreign manufacturers of the radar systems were identified. Questionnaires were sent to manufacturers requesting information concerning the system characteristics: frequency, power used, weight, volume, power radiated, antenna pattern, resolution, display capabilities, pulse repetition frequency, and sensitivity. A literature search was also made to gather the system characteristics information. Results of the survey are documented and comparisons are made among available radar systems.

  15. The Next Generation Airborne Polarimetric Doppler Radar

    NASA Astrophysics Data System (ADS)

    Vivekanandan, J.; Lee, Wen-Chau; Loew, Eric; Salazar, Jorge; Chandrasekar, V.

    2013-04-01

    NCAR's Electra Doppler radar (ELDORA) with a dual-beam slotted waveguide array using dual-transmitter, dual-beam, rapid scan and step-chirped waveform significantly improved the spatial scale to 300m (Hildebrand et al. 1996). However, ELDORA X-band radar's penetration into precipitation is limited by attenuation and is not designed to collect polarimetric measurements to remotely estimate microphysics. ELDORA has been placed on dormancy because its airborne platform (P3 587) was retired in January 2013. The US research community has strongly voiced the need to continue measurement capability similar to the ELDORA. A critical weather research area is quantitative precipitation estimation/forecasting (QPE/QPF). In recent years, hurricane intensity change involving eye-eyewall interactions has drawn research attention (Montgomery et al., 2006; Bell and Montgomery, 2006). In the case of convective precipitation, two issues, namely, (1) when and where convection will be initiated, and (2) determining the organization and structure of ensuing convection, are key for QPF. Therefore collocated measurements of 3-D winds and precipitation microphysics are required for achieving significant skills in QPF and QPE. Multiple radars in dual-Doppler configuration with polarization capability estimate dynamical and microphysical characteristics of clouds and precipitation are mostly available over land. However, storms over complex terrain, the ocean and in forest regions are not observable by ground-based radars (Bluestein and Wakimoto, 2003). NCAR/EOL is investigating potential configurations for the next generation airborne radar that is capable of retrieving dynamic and microphysical characteristics of clouds and precipitation. ELDORA's slotted waveguide array radar is not compatible for dual-polarization measurements. Therefore, the new design has to address both dual-polarization capability and platform requirements to replace the ELDORA system. NCAR maintains a C-130

  16. Evolving subglacial water systems in East Antarctica from airborne radar sounding

    NASA Astrophysics Data System (ADS)

    Carter, Sasha Peter

    The cold, lightless, and high pressure aquatic environment at the base of the East Antarctic Ice Sheet is of interest to a wide range of disciplines. Stable subglacial lakes and their connecting channels remain perennially liquid three kilometers below some of the coldest places on Earth. The presence of subglacial water impacts flow of the overlying ice and provides clues to the geologic properties of the bedrock below, and may harbor unique life forms which have evolved out of contact with the atmosphere for millions of years. Periodic release of water from this system may impact ocean circulation at the margins of the ice sheet. This research uses airborne radar sounding, with its unique ability to infer properties within and at the base of the ice sheet over large spatial scales, to locate and characterize this unique environment. Subglacial lakes, the primary storage mechanism for subglacial water, have been located and classified into four categories on the basis of the radar reflection properties from the sub-ice interface: Definite lakes are brighter than their surroundings by at least two decibels (relatively bright), and are both consistently reflective (specular) and have a reflection coefficient greater than -10 decibels (absolutely bright). Dim lakes are relatively bright and specular but not absolutely bright, possibly indicating non-steady dynamics in the overlying ice. Fuzzy lakes are both relatively and absolutely bright, but not specular, and may indicate saturated sediments or high frequency spatially heterogeneous distributions of sediment and liquid water (i.e. a braided steam). Indistinct lakes are absolutely bright and specular but no brighter than their surroundings. Lakes themselves and the different classes of lakes are not arranged randomly throughout Antarctica but are clustered around ice divides, ice stream onsets and prominent bedrock troughs, with each cluster demonstrating a different characteristic lake classification distribution

  17. Problems of radome design for modern airborne radar

    NASA Astrophysics Data System (ADS)

    Rulf, B.

    1985-01-01

    The operation of airborne radar involves a discrimination between targets and ground clutter. A solution of the resulting problems requires the design of antennas with special characteristics. Efforts of the antenna designer, however, will be defeated if the antenna is protected by a radome which fails to provide the same high performance as the antenna. The present investigation is concerned with problems arising in the design of high-performance radomes, taking into account two important airborne radar systems. The first example involves the E-3A (AWACS), the most modern airborne surveillance radar system now in operation. The second example is related to a typical fire-control radar in a modern tactical aircraft.

  18. Progress report on the NASA/JPL airborne synthetic aperture radar system

    NASA Technical Reports Server (NTRS)

    Lou, Y.; Imel, D.; Chu, A.; Miller, T.; Moller, D.; Skotnicki, W.

    2001-01-01

    AIRSAR has served as a test-bed for both imaging radar techniques and radar technologies for over a decade. In fact, the polarimetric, cross-track interferometric, and along-track introferometric radar techniques were all developed using AIRSAR.

  19. 14 CFR 121.357 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Airborne weather radar equipment... § 121.357 Airborne weather radar equipment requirements. (a) No person may operate any transport... December 31, 1964, unless approved airborne weather radar equipment has been installed in the airplane....

  20. 14 CFR 121.357 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Airborne weather radar equipment... § 121.357 Airborne weather radar equipment requirements. (a) No person may operate any transport... December 31, 1964, unless approved airborne weather radar equipment has been installed in the airplane....

  1. 14 CFR 121.357 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Airborne weather radar equipment... § 121.357 Airborne weather radar equipment requirements. (a) No person may operate any transport... December 31, 1964, unless approved airborne weather radar equipment has been installed in the airplane....

  2. 14 CFR 121.357 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airborne weather radar equipment... § 121.357 Airborne weather radar equipment requirements. (a) No person may operate any transport... December 31, 1964, unless approved airborne weather radar equipment has been installed in the airplane....

  3. 14 CFR 121.357 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Airborne weather radar equipment... § 121.357 Airborne weather radar equipment requirements. (a) No person may operate any transport... December 31, 1964, unless approved airborne weather radar equipment has been installed in the airplane....

  4. The development of a power spectral density processor for C and L band airborne radar scatterometer sensor systems

    NASA Technical Reports Server (NTRS)

    Harrison, D. A., III; Chladek, J. T.

    1983-01-01

    A real-time signal processor was developed for the NASA/JSC L-and C-band airborne radar scatterometer sensor systems. The purpose of the effort was to reduce ground data processing costs. Conversion of two quadrature channels of data (like and cross polarized) was made to obtain Power Spectral Density (PSD) values. A chirp-z transform (CZT) approach was used to filter the Doppler return signal and improved high frequency and angular resolution was realized. The processors have been tested with record signals and excellent results were obtained. CZT filtering can be readily applied to scatterometers operating at other wavelengths by altering the sample frequency. The design of the hardware and software and the results of the performance tests are described in detail.

  5. Airborne Radar Interferometric Repeat-Pass Processing

    NASA Technical Reports Server (NTRS)

    Hensley, Scott; Michel, Thierry R.; Jones, Cathleen E.; Muellerschoen, Ronald J.; Chapman, Bruce D.; Fore, Alexander; Simard, Marc; Zebker, Howard A.

    2011-01-01

    Earth science research often requires crustal deformation measurements at a variety of time scales, from seconds to decades. Although satellites have been used for repeat-track interferometric (RTI) synthetic-aperture-radar (SAR) mapping for close to 20 years, RTI is much more difficult to implement from an airborne platform owing to the irregular trajectory of the aircraft compared with microwave imaging radar wavelengths. Two basic requirements for robust airborne repeat-pass radar interferometry include the ability to fly the platform to a desired trajectory within a narrow tube and the ability to have the radar beam pointed in a desired direction to a fraction of a beam width. Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) is equipped with a precision auto pilot developed by NASA Dryden that allows the platform, a Gulfstream III, to nominally fly within a 5 m diameter tube and with an electronically scanned antenna to position the radar beam to a fraction of a beam width based on INU (inertial navigation unit) attitude angle measurements.

  6. Airborne Differential Doppler Weather Radar

    NASA Technical Reports Server (NTRS)

    Meneghini, R.; Bidwell, S.; Liao, L.; Rincon, R.; Heymsfield, G.; Hildebrand, Peter H. (Technical Monitor)

    2001-01-01

    The Precipitation Radar aboard the Tropical Rain Measuring Mission (TRMM) Satellite has shown the potential for spaceborne sensing of snow and rain by means of an incoherent pulsed radar operating at 13.8 GHz. The primary advantage of radar relative to passive instruments arises from the fact that the radar can image the 3-dimensional structure of storms. As a consequence, the radar data can be used to determine the vertical rain structure, rain type (convective/stratiform) effective storm height, and location of the melting layer. The radar, moreover, can be used to detect snow and improve the estimation of rain rate over land. To move toward spaceborne weather radars that can be deployed routinely as part of an instrument set consisting of passive and active sensors will require the development of less expensive, lighter-weight radars that consume less power. At the same time, the addition of a second frequency and an upgrade to Doppler capability are features that are needed to retrieve information on the characteristics of the drop size distribution, vertical air motion and storm dynamics. One approach to the problem is to use a single broad-band transmitter-receiver and antenna where two narrow-band frequencies are spaced apart by 5% to 10% of the center frequency. Use of Ka-band frequencies (26.5 GHz - 40 GHz) affords two advantages: adequate spatial resolution can be attained with a relatively small antenna and the differential reflectivity and mean Doppler signals are directly related to the median mass diameter of the snow and raindrop size distributions. The differential mean Doppler signal has the additional property that this quantity depends only on that part of the radial speed of the hydrometeors that is drop-size dependent. In principle, the mean and differential mean Doppler from a near-nadir viewing radar can be used to retrieve vertical air motion as well as the total mean radial velocity. In the paper, we present theoretical calculations for the

  7. 14 CFR 125.223 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Airborne weather radar equipment... Equipment Requirements § 125.223 Airborne weather radar equipment requirements. (a) No person may operate an airplane governed by this part in passenger-carrying operations unless approved airborne weather...

  8. 14 CFR 125.223 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airborne weather radar equipment... Equipment Requirements § 125.223 Airborne weather radar equipment requirements. (a) No person may operate an airplane governed by this part in passenger-carrying operations unless approved airborne weather...

  9. 14 CFR 125.223 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Airborne weather radar equipment... Equipment Requirements § 125.223 Airborne weather radar equipment requirements. (a) No person may operate an airplane governed by this part in passenger-carrying operations unless approved airborne weather...

  10. 14 CFR 135.175 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airborne weather radar equipment... Aircraft and Equipment § 135.175 Airborne weather radar equipment requirements. (a) No person may operate a large, transport category aircraft in passenger-carrying operations unless approved airborne...

  11. 14 CFR 135.175 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Airborne weather radar equipment... Aircraft and Equipment § 135.175 Airborne weather radar equipment requirements. (a) No person may operate a large, transport category aircraft in passenger-carrying operations unless approved airborne...

  12. 14 CFR 125.223 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Airborne weather radar equipment... Equipment Requirements § 125.223 Airborne weather radar equipment requirements. (a) No person may operate an airplane governed by this part in passenger-carrying operations unless approved airborne weather...

  13. 14 CFR 135.175 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Airborne weather radar equipment... Aircraft and Equipment § 135.175 Airborne weather radar equipment requirements. (a) No person may operate a large, transport category aircraft in passenger-carrying operations unless approved airborne...

  14. 14 CFR 125.223 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Airborne weather radar equipment... Equipment Requirements § 125.223 Airborne weather radar equipment requirements. (a) No person may operate an airplane governed by this part in passenger-carrying operations unless approved airborne weather...

  15. 14 CFR 135.175 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Airborne weather radar equipment... Aircraft and Equipment § 135.175 Airborne weather radar equipment requirements. (a) No person may operate a large, transport category aircraft in passenger-carrying operations unless approved airborne...

  16. 14 CFR 135.175 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Airborne weather radar equipment... Aircraft and Equipment § 135.175 Airborne weather radar equipment requirements. (a) No person may operate a large, transport category aircraft in passenger-carrying operations unless approved airborne...

  17. Description and availability of airborne Doppler radar data

    NASA Technical Reports Server (NTRS)

    Harrah, S. D.; Bracalente, E. M.; Schaffner, P. R.; Baxa, E. G.

    1993-01-01

    An airborne, forward-looking, pulse, Doppler radar has been developed in conjunction with the joint FAA/NASA Wind Shear Program. This radar represents a first in an emerging technology. The radar was developed to assess the applicability of an airborne radar to detect low altitude hazardous wind shears for civil aviation applications. Such a radar must be capable of looking down into the ground clutter environment and extracting wind estimates from relatively low reflectivity weather targets. These weather targets often have reflectivities several orders of magnitude lower than the surrounding ground clutter. The NASA radar design incorporates numerous technological and engineering achievements in order to accomplish this task. The basic R/T unit evolved from a standard Collins 708 weather radar, which supports specific pulse widths of 1-7 microns and Pulse Repetition Frequencies (PRF) of less than 1-10 kHz. It was modified to allow for the output of the first IF signal, which fed a NASA developed receiver/detector subsystem. The NASA receiver incorporated a distributed, high-speed digital attenuator, producing a range bin to range bin automatic gain control system with 65 dB of dynamic range. Using group speed information supplied by the aircraft's navigation system, the radar signal is frequency demodulated back to base band (zero Doppler relative to stationary ground). The In-phase & Quadrature-phase (I/Q) components of the measured voltage signal are then digitized by a 12-bit A-D converter (producing an additional 36 dB of dynamic range). The raw I/Q signal for each range bin is then recorded (along with the current radar & aircraft state parameters) by a high-speed Kodak tape recorder.

  18. The evolutionary trend in airborne and satellite radar altimeters

    NASA Technical Reports Server (NTRS)

    Fedor, L. S.; Walsh, E. J.

    1984-01-01

    The manner in which airborne and satellite radar altimeters developed and where the trend is leading was investigated. The airborne altimeters have progressed from a broad beamed, narrow pulsed, nadir looking instrument, to a pulse compressed system that is computer controlled, to a scanning pencil beamed system which produce a topographic map of the surface beneath the aircraft in real time. It is suggested that the airborne systems lie in the use of multiple frequencies. The satellite altimeters evolve towards multifrequency systems with narrower effective pulses and higher pulse compression ratios to reduce peak transmitted power while improving resolution. Applications indicate wide swath systems using interferometric techniques or beam limited systems using 100 m diameter antennas.

  19. A wing pod-based millimeter wavelength airborne cloud radar

    NASA Astrophysics Data System (ADS)

    Vivekanandan, J.; Ellis, S.; Tsai, P.; Loew, E.; Lee, W.-C.; Emmett, J.; Dixon, M.; Burghart, C.; Rauenbuehler, S.

    2015-08-01

    This paper describes a novel, airborne pod-based millimeter (mm) wavelength radar. Its frequency of operation is 94 GHz (3 mm wavelength). The radar has been designed to fly on the NCAR Gulfstream V HIAPER aircraft; however, it could be deployed on other similarly equipped aircraft. The pod-based configuration occupies minimum cabin space and maximizes scan coverage. The radar system is capable of collecting observations in a staring mode between zenith and nadir or in a scanning mode. Standard pulse-pair estimates of moments and raw time series of backscattered signals are recorded. The radar system design and characteristics as well as techniques for calibrating reflectivity and correcting Doppler velocity for aircraft attitude and motion are described. The radar can alternatively be deployed in a ground-based configuration, housed in the 20 ft shipping container it shares with the High Spectral Resolution Lidar (HSRL). The radar was tested both on the ground and in flight. Preliminary measurements of Doppler and polarization measurements were collected and examples are presented.

  20. A wing pod-based millimeter wavelength airborne cloud radar

    NASA Astrophysics Data System (ADS)

    Vivekanandan, J.; Ellis, S.; Tsai, P.; Loew, E.; Lee, W. C.; Emmett, J.; Dixon, M.; Burghart, C.; Rauenbuehler, S.

    2015-04-01

    This paper describes a novel, airborne pod-based millimeter wavelength radar. Its frequency of operation is 94 GHz (3 mm wavelength). The radar has been designed to fly on the NCAR Gulfstream V HIAPER aircraft; however, it could be deployed on other similarly equipped aircraft. The pod-based configuration occupies minimum cabin space and maximizes scan coverage. The radar system is capable of collecting observations in a staring mode between zenith and nadir or in a scanning mode. Standard pulse-pair estimates of moments and raw time series of backscattered signals are recorded. The radar system design and characteristics, as well as techniques for calibrating reflectivity and correcting Doppler velocity for aircraft attitude and motion are described. The radar can alternatively be deployed in a ground-based configuration, housed in the 20 ft shipping container it shares with the High Spectral Resolution Lidar (HSRL). The radar was tested both on the ground and in flight. Preliminary measurements of Doppler and polarization measurements were collected and examples are presented.

  1. Comparison of TRMM Precipitation Radar and Airborne Radar Data.

    NASA Astrophysics Data System (ADS)

    Durden, S. L.; Im, E.; Haddad, Z. S.; Li, L.

    2003-06-01

    The first spaceborne weather radar is the precipitation radar (PR) on the Tropical Rainfall Measuring Mission (TRMM), which was launched in 1997. As part of the TRMM calibration and validation effort, an airborne rain-mapping radar (ARMAR) was used to make underflights of TRMM during the B portion of the Texas and Florida Underflights (TEFLUN-B) and the third Convection and Moisture Experiment (CAMEX-3) in 1998 and the Kwajalein Experiment (KWAJEX) in 1999. The TRMM PR and ARMAR both operate at 14 GHz, and both instruments use a downward-looking, cross-track scanning geometry, which allows direct comparison of data. Nearly simultaneous PR and ARMAR data were acquired in seven separate cases. These data are compared to examine the effects of larger resolution volume and lower sensitivity in the PR data relative to ARMAR. The PR and ARMAR data show similar structures, although the PR data tend to have lower maximum reflectivities and path attenuations because of nonuniform beam-filling effects. Nonuniform beam filling can also cause a bias in the observed path attenuation relative to that corresponding to the beam-averaged rain rate. The PR rain-type classification is usually consistent with the ARMAR data.

  2. Minimum operational performance standards for airborne weather and ground mapping pulsed radars

    NASA Astrophysics Data System (ADS)

    1980-11-01

    Minimum operational performance standards for airborne weather and ground mapping pulsed radars, including both air carrier and large aircraft-type radar systems, are described. Those requirements and technologies pertinent to general aviation, where limitations on space and/or weight may apply are taken into account.

  3. Airborne Radar Observations of Severe Hailstorms: Implications for Future Spaceborne Radar

    NASA Technical Reports Server (NTRS)

    Heymsfield, Gerald M.; Tian, Lin; Li, Lihua; McLinden, Matthew; Cervantes, Jaime I.

    2013-01-01

    A new dual-frequency (Ku and Ka band) nadir-pointing Doppler radar on the high-altitude NASA ER-2 aircraft, called the High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP), has collected data over severe thunderstorms in Oklahoma and Kansas during the Midlatitude Continental Convective Clouds Experiment (MC3E). The overarching motivation for this study is to understand the behavior of the dualwavelength airborne radar measurements in a global variety of thunderstorms and how these may relate to future spaceborne-radar measurements. HIWRAP is operated at frequencies that are similar to those of the precipitation radar on the Tropical Rainfall Measuring Mission (Ku band) and the upcoming Global Precipitation Measurement mission satellite's dual-frequency (Ku and Ka bands) precipitation radar. The aircraft measurements of strong hailstorms have been combined with ground-based polarimetric measurements to obtain a better understanding of the response of the Ku- and Ka-band radar to the vertical distribution of the hydrometeors, including hail. Data from two flight lines on 24 May 2011 are presented. Doppler velocities were approx. 39m/s2at 10.7-km altitude from the first flight line early on 24 May, and the lower value of approx. 25m/s on a second flight line later in the day. Vertical motions estimated using a fall speed estimate for large graupel and hail suggested that the first storm had an updraft that possibly exceeded 60m/s for the more intense part of the storm. This large updraft speed along with reports of 5-cm hail at the surface, reflectivities reaching 70 dBZ at S band in the storm cores, and hail signals from polarimetric data provide a highly challenging situation for spaceborne-radar measurements in intense convective systems. The Ku- and Ka-band reflectivities rarely exceed approx. 47 and approx. 37 dBZ, respectively, in these storms.

  4. Knowledge Based Systems and Metacognition in Radar

    NASA Astrophysics Data System (ADS)

    Capraro, Gerard T.; Wicks, Michael C.

    An airborne ground looking radar sensor's performance may be enhanced by selecting algorithms adaptively as the environment changes. A short description of an airborne intelligent radar system (AIRS) is presented with a description of the knowledge based filter and detection portions. A second level of artificial intelligence (AI) processing is presented that monitors, tests, and learns how to improve and control the first level. This approach is based upon metacognition, a way forward for developing knowledge based systems.

  5. Measurement of backscattering from sea with an airborne radar at L band

    NASA Astrophysics Data System (ADS)

    Luo, Xianyun; Zhang, Zhongzhi; Yin, Zhiying; Sun, Fang; Kang, Shifeng; Wang, Laibu; Yu, Yunchao; Wen, Fangru

    1998-08-01

    Measurements of electromagnetic backscattering from sea surface at L band have been done with airborne side-looking radar system. Several flights are made for various sea states. Coherent radar data ta HH polarization and some truth data such as wave height, wind velocity and direction, temperature of sea water are recorded. Corner reflectors and active backscattering coefficient can be derived from the radar data and the cinematic data. The result presented in this paper include scattering coefficient and statistical analysis of radar echo with typical probability distribution functions such as Rayleigh, Weibull, Log-normal and K distribution.

  6. Millimeter-wave radar sensing of airborne chemicals.

    SciTech Connect

    Gopalsami, N.; Raptis, A. C.; Energy Technology

    2001-04-01

    This paper discusses the development of a millimeter-wave radar chemical sensor for applications in environmental monitoring and arms-control treaty verification. The purpose of this paper is to investigate the use of fingerprint-type molecular rotational signatures in the millimeter-wave spectrum to sense airborne chemicals. The millimeter-wave sensor, operating in the frequency range of 225-315 GHz, can work under all weather conditions and in smoky and dusty environments. The basic configuration of the millimeter-wave sensor is a monostatic swept-frequency radar that consists of a millimeter-wave sweeper, a hot-electron bolometer or Schottky barrier detector, and a corner-cube reflector. The chemical plume to be detected is situated between the transmitter/detector and reflector. Millimeter-wave absorption spectra of chemicals in the plume are determined by measuring the swept-frequency radar return signals with and without the plume in the beam path. The problem of pressure broadening, which hampered open-path spectroscopy in the past, has been mitigated in this paper by designing a fast sweeping source over a broad frequency range. The heart of the system is a backward-wave oscillator (BWO) tube that can be tuned over 220-350 GHz. Using the BWO tube, we built a millimeter-wave radar system and field-tested it at the Department of Energy Nevada Test Site, Frenchman Flat, near Mercury, NV, at a standoff distance of 60 m, The millimeter-wave system detected chemical plumes very well; detection sensitivity for polar molecules such as methylchloride was down to 12 ppm for a 4-m two-way pathlength.

  7. 77 FR 21834 - Airborne Radar Altimeter Equipment (For Air Carrier Aircraft)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-11

    ... Federal Aviation Administration Airborne Radar Altimeter Equipment (For Air Carrier Aircraft) AGENCY..., Airborne Radar Altimeter Equipment (For Air Carrier Aircraft). SUMMARY: This is a confirmation notice of the cancellation of TSO-C67, Airborne Radar Altimeter Equipment (For Air Carrier Aircraft). The...

  8. Crop classification using airborne radar and LANDSAT data. [Colby, Kansas

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T. (Principal Investigator); Li, R. Y.; Shanmugam, K. S.

    1981-01-01

    Airborne radar data acquired with a 13.3 GHz scatterometer over a test-site near Colby, Kansas were used to investigate the statistical properties of the scattering coefficient of three types of vegetation cover and of bare soil. A statistical model for radar data was developed that incorporates signal-fading and natural within-field variabilities. Estimates of the within-field and between-field coefficients of variation were obtained for each cover-type and compared with similar quantities derived from LANDSAT images of the same fields. The classification accuracy provided by LANDSAT alone, radar alone, and both sensors combined was investigated. The results indicate that the addition of radar to LANDSAT improves the classification accuracy by about 10; percentage-points when the classification is performed on a pixel basis and by about 15 points when performed on a field-average basis.

  9. Airborne Synthetic Aperature Radar (AIRSAR) on left rear fuselage of DC-8 Airborne Laboratory

    NASA Technical Reports Server (NTRS)

    1998-01-01

    A view of the Airborne Synthetic Aperature Radar (AIRSAR) antenna on the left rear fuselage of the DC-8. The AIRSAR captures images of the ground from the side of the aircraft and can provide precision digital elevation mapping capabilities for a variety of studies. The AIRSAR is one of a number of research systems that have been added to the DC-8. NASA is using a DC-8 aircraft as a flying science laboratory. The platform aircraft, based at NASA's Dryden Flight Research Center, Edwards, Calif., collects data for many experiments in support of scientific projects serving the world scientific community. Included in this community are NASA, federal, state, academic and foreign investigators. Data gathered by the DC-8 at flight altitude and by remote sensing have been used for scientific studies in archeology, ecology, geography, hydrology, meteorology, oceanography, volcanology, atmospheric chemistry, soil science and biology.

  10. Characterizing Englacial and Subglacial Temperature Structure Using Airborne Radar Sounding

    NASA Astrophysics Data System (ADS)

    Schroeder, D. M.; Seroussi, H. L.

    2015-12-01

    The temperature structure of ice sheet and glaciers is a fundamental control on ice flow, rheology, and stability. However, it is difficult to observationally constrain temperature structures at the catchment to ice-sheet scale. The englacial attenuation of radar sounding data is strongly dependent on the temperature structure of the ice sheets. Therefore, echo strength profiles from airborne radar sounding observation do contain temperature information. However, direct interpretation of englacial attenuation rates from radar sounding profiles is often difficult or impossible due to the ambiguous contribution the geometric and material properties of the bed to echo strength variations. To overcome this challenge, we presents techniques that treat radar sounding echo strength and ice thickness profiles as continuous signals, taking advantage of along-profile ice thickness and echo strength variations to constrain the spatial pattern of englacial attenuation and basal reflectivity. We then apply these techniques to an airborne radar sounding survey in order to characterize the englacial and subglacial temperature structure of the Thwaites Glacier catchment in West Antarctic. We then interpreted this structure in context of local ice sheet velocity, advection, force balance, and bed conditions using the ISSM ice sheet model.

  11. Proceedings of the Third Airborne Synthetic Aperture Radar (AIRSAR) Workshop

    NASA Technical Reports Server (NTRS)

    Vanzyl, Jakob J. (Editor)

    1991-01-01

    The Third Airborne Synthetic Aperture Radar (AIRSAR) Workshop was held on 23-24 May 1991 at JPL. Thirty oral presentations were made and 18 poster papers displayed during the workshop. Papers from these 25 presentations are presented which include analyses of AIRSAR operations and studies in SAR remote sensing, ecology, hydrology, soil science, geology, oceanography, volcanology, and SAR mapping and data handling. Results from these studies indicate the direction and emphasis of future orbital radar-sensor missions that will be launched during the 1990's.

  12. Hydrometeor discrimination in melting layer using multiparameter airborne radar measurement

    NASA Technical Reports Server (NTRS)

    Kumagai, H.; Meneghini, R.; Kozu, T.

    1992-01-01

    Results from a multiparameter airborne radar/radiometer experiment (the Typhoon experiment) are presented. The experiment was conducted in the western Pacific with the NASA DC-8 aircraft, in which a dual-wavelength at X-band and Ka-band and dual-polarization at X-band radar was installed. The signatures of dBZ(X), dBZ(Ka), LDR (linear depolarization ratio) at X-band and DZ=dBZ(X)-dBZ(Ka) are discussed for the data obtained in the penetration of the typhoon Flo. With emphasis on discrimination of hydrometeor particles, some statistical features of the brightband in stratiform rain are discussed.

  13. Investigation of image enhancement techniques for the development of a self-contained airborne radar navigation system

    NASA Technical Reports Server (NTRS)

    Phatak, A. V.; Karmali, M. S.

    1983-01-01

    This study was devoted to an investigation of the feasibility of applying advanced image processing techniques to enhance radar image characteristics that are pertinent to the pilot's navigation and guidance task. Millimeter (95 GHz) wave radar images for the overwater (i.e., offshore oil rigs) and overland (Heliport) scenario were used as a data base. The purpose of the study was to determine the applicability of image enhancement and scene analysis algorithms to detect and improve target characteristics (i.e., manmade objects such as buildings, parking lots, cars, roads, helicopters, towers, landing pads, etc.) that would be helpful to the pilot in determining his own position/orientation with respect to the outside world and assist him in the navigation task. Results of this study show that significant improvements in the raw radar image may be obtained using two dimensional image processing algorithms. In the overwater case, it is possible to remove the ocean clutter by thresholding the image data, and furthermore to extract the target boundary as well as the tower and catwalk locations using noise cleaning (e.g., median filter) and edge detection (e.g., Sobel operator) algorithms.

  14. Airborne oceanographic lidar system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Specifications and preliminary design of an Airborne Oceanographic Lidar (AOL) system, which is to be constructed for installation and used on a NASA Wallops Flight Center (WFC) C-54 research aircraft, are reported. The AOL system is to provide an airborne facility for use by various government agencies to demonstrate the utility and practicality of hardware of this type in the wide area collection of oceanographic data on an operational basis. System measurement and performance requirements are presented, followed by a description of the conceptual system approach and the considerations attendant to its development. System performance calculations are addressed, and the system specifications and preliminary design are presented and discussed.

  15. Enhanced Weather Radar (EWxR) System

    NASA Technical Reports Server (NTRS)

    Kronfeld, Kevin M. (Technical Monitor)

    2003-01-01

    An airborne weather radar system, the Enhanced Weather Radar (EWxR), with enhanced on-board weather radar data processing was developed and tested. The system features additional weather data that is uplinked from ground-based sources, specialized data processing, and limited automatic radar control to search for hazardous weather. National Weather Service (NWS) ground-based Next Generation Radar (NEXRAD) information is used by the EWxR system to augment the on-board weather radar information. The system will simultaneously display NEXRAD and on-board weather radar information in a split-view format. The on-board weather radar includes an automated or hands-free storm-finding feature that optimizes the radar returns by automatically adjusting the tilt and range settings for the current altitude above the terrain and searches for storm cells near the atmospheric 0-degree isotherm. A rule-based decision aid was developed to automatically characterize cells as hazardous, possibly-hazardous, or non-hazardous based upon attributes of that cell. Cell attributes are determined based on data from the on-board radar and from ground-based radars. A flight path impact prediction algorithm was developed to help pilots to avoid hazardous weather along their flight plan and their mission. During development the system was tested on the NASA B757 aircraft and final tests were conducted on the Rockwell Collins Sabreliner.

  16. Noncooperative rendezvous radar system

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A fire control radar system was developed, assembled, and modified. The baseline system and modified angle tracking system are described along with the performance characteristics of the baseline and modified systems. Proposed changes to provide additional techniques for radar evaluation are presented along with flight test data.

  17. Prediction and uncertainty of Hurricane Sandy (2012) explored through a real-time cloud-permitting ensemble analysis and forecast system assimilating airborne Doppler radar observations

    NASA Astrophysics Data System (ADS)

    Munsell, Erin B.; Zhang, Fuqing

    2014-03-01

    the Pennsylvania State University (PSU) real-time convection-permitting hurricane analysis and forecasting system (WRF-EnKF) that assimilates airborne Doppler radar observations, the sensitivity and uncertainty of forecasts initialized several days prior to landfall of Hurricane Sandy (2012) are assessed. The performance of the track and intensity forecasts of both the deterministic and ensemble forecasts by the PSU WRF-EnKF system show significant skill and are comparable to or better than forecasts produced by operational dynamical models, even at lead times of 4-5 days prior to landfall. Many of the ensemble members correctly capture the interaction of Sandy with an approaching midlatitude trough, which precedes Sandy's forecasted landfall in the Mid-Atlantic region of the United States. However, the ensemble reveals considerable forecast uncertainties in the prediction of Sandy. For example, in the ensemble forecast initialized at 0000 UTC 26 October 2012, 10 of the 60 members do not predict a United States landfall. Using ensemble composite and sensitivity analyses, the essential dynamics and initial condition uncertainties that lead to forecast divergence among the members in tracks and precipitation are examined. It is observed that uncertainties in the environmental steering flow are the most impactful factor on the divergence of Sandy's track forecasts, and its subsequent interaction with the approaching midlatitude trough. Though the midlatitude system does not strongly influence the final position of Sandy, differences in the timing and location of its interactions with Sandy lead to considerable differences in rainfall forecasts, especially with respect to heavy precipitation over land.

  18. Airborne radar technology for windshear detection

    NASA Technical Reports Server (NTRS)

    Hibey, Joseph L.; Khalaf, Camille S.

    1988-01-01

    The objectives and accomplishments of the two-and-a-half year effort to describe how returns from on-board Doppler radar are to be used to detect the presence of a wind shear are reported. The problem is modeled as one of first passage in terms of state variables, the state estimates are generated by a bank of extended Kalman filters working in parallel, and the decision strategy involves the use of a voting algorithm for a series of likelihood ratio tests. The performance issue for filtering is addressed in terms of error-covariance reduction and filter divergence, and the performance issue for detection is addressed in terms of using a probability measure transformation to derive theoretical expressions for the error probabilities of a false alarm and a miss.

  19. Validation of Airborne FMCW Radar Measurements of Snow Thickness Over Sea Ice in Antarctica

    NASA Technical Reports Server (NTRS)

    Galin, Natalia; Worby, Anthony; Markus, Thorsten; Leuschen, Carl; Gogineni, Prasad

    2012-01-01

    Antarctic sea ice and its snow cover are integral components of the global climate system, yet many aspects of their vertical dimensions are poorly understood, making their representation in global climate models poor. Remote sensing is the key to monitoring the dynamic nature of sea ice and its snow cover. Reliable and accurate snow thickness data are currently a highly sought after data product. Remotely sensed snow thickness measurements can provide an indication of precipitation levels, predicted to increase with effects of climate change in the polar regions. Airborne techniques provide a means for regional-scale estimation of snow depth and distribution. Accurate regional-scale snow thickness data will also facilitate an increase in the accuracy of sea ice thickness retrieval from satellite altimeter freeboard estimates. The airborne data sets are easier to validate with in situ measurements and are better suited to validating satellite algorithms when compared with in situ techniques. This is primarily due to two factors: better chance of getting coincident in situ and airborne data sets and the tractability of comparison between an in situ data set and the airborne data set averaged over the footprint of the antennas. A 28-GHz frequency modulated continuous wave (FMCW) radar loaned by the Center for Remote Sensing of Ice Sheets to the Australian Antarctic Division is used to measure snow thickness over sea ice in East Antarctica. Provided with the radar design parameters, the expected performance parameters of the radar are summarized. The necessary conditions for unambiguous identification of the airsnow and snowice layers for the radar are presented. Roughnesses of the snow and ice surfaces are found to be dominant determinants in the effectiveness of layer identification for this radar. Finally, this paper presents the first in situ validated snow thickness estimates over sea ice in Antarctica derived from an FMCW radar on a helicopterborne platform.

  20. Algorithms for airborne Doppler radar wind shear detection

    NASA Technical Reports Server (NTRS)

    Gillberg, Jeff; Pockrandt, Mitch; Symosek, Peter; Benser, Earl T.

    1992-01-01

    Honeywell has developed algorithms for the detection of wind shear/microburst using airborne Doppler radar. The Honeywell algorithms use three dimensional pattern recognition techniques and the selection of an associated scanning pattern forward of the aircraft. This 'volumetric scan' approach acquires reflectivity, velocity, and spectral width from a three dimensional volume as opposed to the conventional use of a two dimensional azimuthal slice of data at a fixed elevation. The algorithm approach is based on detection and classification of velocity patterns which are indicative of microburst phenomenon while minimizing the false alarms due to ground clutter return. Simulation studies of microburst phenomenon and x-band radar interaction with the microburst have been performed and results of that study are presented. Algorithm performance indetection of both 'wet' and 'dry' microbursts is presented.

  1. Real-time simulation of an airborne radar for overwater approaches

    NASA Technical Reports Server (NTRS)

    Karmarkar, J.; Clark, D.

    1982-01-01

    Software developed to provide a real time simulation of an airborne radar for overwater approaches to oil rig platforms is documented. The simulation is used to study advanced concepts for enhancement of airborne radar approaches (ARA) in order to reduce crew workload, improve approach tracking precision, and reduce weather minimums. ARA's are currently used for offshore helicopter operations to and from oil rigs.

  2. Goldstone solar system radar

    NASA Technical Reports Server (NTRS)

    Jurgens, Raymond F.

    1988-01-01

    Planning, direction, experimental design, and coordination of data-acquisition and engineering activities in support of all Goldstone planetary radar astronomy were performed. This work demands familiarity with the various components of a planetary radar telescope (transmitter, receiver, antenna, computer hardware and software) as well as knowledge of how the entire system must function as a cohesive unit to meet the particular scientific objectives at hand in a given observation. Support radar data-processing facilities, currently being used for virtually all Goldstone data reduction includes: a VAX 11/780 computer system, an FPS 5210 array processor, terminals, tape drives, and image-display devices, as well as a large body of data-reduction software to accommodate the variety of data-acquisition formats and strategems. Successful 113-cm radar observation of Callisto and the near-Earth asteroid 1981 Midas and Goldstone/VLA radar observations of Saturn's rings were obtained. Quick-look verification programs from data taken with phase-coded cw (i.e., ranging) waveforms, applicable to Venus, the Moon, and small bodies were completed. Definition of scientific and engineering requirements on instrument performance, radar system configuration, and personnel, for all 1988 Goldstone radar investigations was accomplished.

  3. Simultaneous observations of structure function parameter of refractive index using a high-resolution radar and the DataHawk small airborne measurement system

    NASA Astrophysics Data System (ADS)

    Scipión, Danny E.; Lawrence, Dale A.; Milla, Marco A.; Woodman, Ronald F.; Lume, Diego A.; Balsley, Ben B.

    2016-09-01

    The SOUSY (SOUnding SYstem) radar was relocated to the Jicamarca Radio Observatory (JRO) near Lima, Peru, in 2000, where the radar controller and acquisition system were upgraded with state-of-the-art parts to take full advantage of its potential for high-resolution atmospheric sounding. Due to its broad bandwidth (4 MHz), it is able to characterize clear-air backscattering with high range resolution (37.5 m). A campaign conducted at JRO in July 2014 aimed to characterize the lower troposphere with a high temporal resolution (8.1 Hz) using the DataHawk (DH) small unmanned aircraft system, which provides in situ atmospheric measurements at scales as small as 1 m in the lower troposphere and can be GPS-guided to obtain measurements within the beam of the radar. This was a unique opportunity to make coincident observations by both systems and to directly compare their in situ and remotely sensed parameters. Because SOUSY only points vertically, it is only possible to retrieve vertical radar profiles caused by changes in the refractive index within the resolution volume. Turbulent variations due to scattering are described by the structure function parameter of refractive index Cn2. Profiles of Cn2 from the DH are obtained by combining pressure, temperature, and relative humidity measurements along the helical trajectory and integrated at the same scale as the radar range resolution. Excellent agreement is observed between the Cn2 estimates obtained from the DH and SOUSY in the overlapping measurement regime from 1200 m up to 4200 m above sea level, and this correspondence provides the first accurate calibration of the SOUSY radar for measuring Cn2.

  4. Airborne Oceanographic Lidar System

    NASA Technical Reports Server (NTRS)

    Bressel, C.; Itzkan, I.; Nunes, J. E.; Hoge, F.

    1977-01-01

    The Airborne Oceanographic Lidar (AOL), a spatially scanning range-gated device installed on board a NASA C-54 aircraft, is described. The AOL system is capable of measuring topographical relief or water depth (bathymetry) with a range resolution of plus or minus 0.3 m in the vertical dimension. The system may also be used to measure fluorescent spectral signatures from 3500 to 8000 A with a resolution of 100 A. Potential applications of the AOL, including sea state measurements, water transparency assessments, oil spill identification, effluent identification and crop cover assessment are also mentioned.

  5. Demonstration of radar reflector detection and ground clutter suppression using airborne weather and mapping radar

    NASA Technical Reports Server (NTRS)

    Anderson, D. J.; Bull, J. S.; Chisholm, J. P.

    1982-01-01

    A navigation system which utilizes minimum ground-based equipment is especially advantageous to helicopters, which can make off-airport landings. Research has been conducted in the use of weather and mapping radar to detect large radar reflectors overland for navigation purposes. As initial studies have not been successful, investigations were conducted regarding a new concept for the detection of ground-based radar reflectors and eliminating ground clutter, using a device called an echo processor (EP). A description is presented of the problems associated with detecting radar reflectors overland, taking into account the EP concept and the results of ground- and flight-test investigations. The echo processor concept was successfully demonstrated in detecting radar reflectors overland in a high-clutter environment. A radar reflector target size of 55 dBsm was found to be adequate for detection in an urban environment.

  6. The U.S. Geological Survey side-looking airborne radar database: an aid to the interpretation of space images

    USGS Publications Warehouse

    Kover, Allan N.; Schoonmaker, James W.

    1993-01-01

    The U.S. Geological Survey (USGS) has a database of side-looking airborne radar (SLAR) images of a significant part of the continental United States. These images provide a regional view of terrains and should be an aid to better understanding image data of satellite synthetic aperture radar (SAR) and other systems. The USGS has been systematically collecting SLAR since 1980, initially in analog form, then in both analog and digital format since 1984.

  7. Description, characteristics and testing of the NASA airborne radar

    NASA Technical Reports Server (NTRS)

    Jones, W. R.; Altiz, O.; Schaffner, P.; Schrader, J. H.; Blume, H. J. C.

    1991-01-01

    Presented here is a description of a coherent radar scattermeter and its associated signal processing hardware, which have been specifically designed to detect microbursts and record their radar characteristics. Radar parameters, signal processing techniques and detection algorithms, all under computer control, combine to sense and process reflectivity, clutter, and microburst data. Also presented is the system's high density, high data rate recording system. This digital system is capable of recording many minutes of the in-phase and quadrature components and corresponding receiver gains of the scattered returns for selected spatial regions, as well as other aircraft and hardware related parameters of interest for post-flight analysis. Information is given in viewgraph form.

  8. Ground clutter measurements using the NASA airborne doppler radar: Description of clutter at the Denver and Philadelphia airports

    NASA Technical Reports Server (NTRS)

    Harrah, Steven D.; Delnore, Victor E.; Goodrich, Michael S.; Vonhagel, Chris

    1992-01-01

    Detection of hazardous wind shears from an airborne platform, using commercial sized radar hardware, has been debated and researched for several years. The primary concern has been the requirement for 'look-down' capability in a Doppler radar during the approach and landing phases of flight. During 'look-down' operation, the received signal (weather signature) will be corrupted by ground clutter returns. Ground clutter at and around urban airports can have large values of Normalized Radar Cross Section (NRCS) producing clutter returns which could saturate the radar's receiver, thus disabling the radar entirely, or at least from its intended function. The purpose of this research was to investigate the NRCS levels in an airport environment (scene), and to characterize the NRCS distribution across a variety of radar parameters. These results are also compared to results of a similar study using Synthetic Aperture Radar (SAR) images of the same scenes. This was necessary in order to quantify and characterize the differences and similarities between results derived from the real-aperature system flown on the NASA 737 aircraft and parametric studies which have previously been performed using the NASA airborne radar simulation program.

  9. Airborne ballistic camera tracking systems

    NASA Technical Reports Server (NTRS)

    Redish, W. L.

    1976-01-01

    An operational airborne ballistic camera tracking system was tested for operational and data reduction feasibility. The acquisition and data processing requirements of the system are discussed. Suggestions for future improvements are also noted. A description of the data reduction mathematics is outlined. Results from a successful reentry test mission are tabulated. The test mission indicated that airborne ballistic camera tracking systems are feasible.

  10. Simulation of multistatic and backscattering cross sections for airborne radar

    NASA Astrophysics Data System (ADS)

    Biggs, Albert W.

    1986-07-01

    In order to determine susceptibilities of airborne radar to electronic countermeasures and electronic counter-countermeasures simulations of multistatic and backscattering cross sections were developed as digital modules in the form of algorithms. Cross section algorithms are described for prolate (cigar shape) and oblate (disk shape) spheroids. Backscattering cross section algorithms are also described for different categories of terrain. Backscattering cross section computer programs were written for terrain categorized as vegetation, sea ice, glacial ice, geological (rocks, sand, hills, etc.), oceans, man-made structures, and water bodies. PROGRAM SIGTERRA is a file for backscattering cross section modules of terrain (TERRA) such as vegetation (AGCROP), oceans (OCEAN), Arctic sea ice (SEAICE), glacial snow (GLASNO), geological structures (GEOL), man-made structures (MAMMAD), or water bodies (WATER). AGCROP describes agricultural crops, trees or forests, prairies or grassland, and shrubs or bush cover. OCEAN has the SLAR or SAR looking downwind, upwind, and crosswind at the ocean surface. SEAICE looks at winter ice and old or polar ice. GLASNO is divided into a glacial ice and snow or snowfields. MANMAD includes buildings, houses, roads, railroad tracks, airfields and hangars, telephone and power lines, barges, trucks, trains, and automobiles. WATER has lakes, rivers, canals, and swamps. PROGRAM SIGAIR is a similar file for airborne targets such as prolate and oblate spheroids.

  11. UAVSAR: Airborne L-band Radar for Repeat Pass Interferometry

    NASA Technical Reports Server (NTRS)

    Moes, Timothy R.

    2009-01-01

    The primary objectives of the UAVSAR Project were to: a) develop a miniaturized polarimetric L-band synthetic aperture radar (SAR) for use on an unmanned aerial vehicle (UAV) or piloted vehicle. b) develop the associated processing algorithms for repeat-pass differential interferometric measurements using a single antenna. c) conduct measurements of geophysical interest, particularly changes of rapidly deforming surfaces such as volcanoes or earthquakes. Two complete systems were developed. Operational Science Missions began on February 18, 2009 ... concurrent development and testing of the radar system continues.

  12. Comparison of winds, waves, and turbulence as observed by airborne lidar, ground-based radars, and instrumented tower

    NASA Technical Reports Server (NTRS)

    Eilts, M. D.; Doviak, R. J.; Sundara-Rajan, A.

    1984-01-01

    On June 29, 1981, two ground-based Doppler radars, an airborne Doppler optical radar (lidar), an instrumented tower, and a rawinsonde were employed to collect wind data in the planetary boundary layer (PBL) in central Oklahoma. The main objectives of this experiment were related to a comparison of wind estimates and the visualization of the three-dimensional eddy structure in the convective atmospheric boundary layer. Discrepancies in the mean wind and wind profile detected by the different sensing systems were explained as being caused by a Schuler resonance of the aircraft's inertial navigation system, which caused an erroneous component of the aircraft's ground-relative velocity vector to be subtracted from the lidar-measured radial velocities. It is concluded that NASA's airborne Doppler optical radar system is capable of measuring wind fields in clear air on a smaller scale than was previously available with fixed remote sensors.

  13. Definition and fabrication of an airborne scatterometer radar signal processor

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A hardware/software system which incorporates a microprocessor design and software for the calculation of normalized radar cross section in real time was developed. Interface is provided to decommutate the NASA ADAS data stream for aircraft parameters used in processing and to provide output in the form of strip chart and pcm compatible data recording.

  14. Detecting and mitigating wind turbine clutter for airspace radar systems.

    PubMed

    Wang, Wen-Qin

    2013-01-01

    It is well recognized that a wind turbine has a large radar cross-section (RCS) and, due to the movement of the blades, the wind turbine will generate a Doppler frequency shift. This scattering behavior may cause severe interferences on existing radar systems including static ground-based radars and spaceborne or airborne radars. To resolve this problem, efficient techniques or algorithms should be developed to mitigate the effects of wind farms on radars. Herein, one transponder-based mitigation technique is presented. The transponder is not a new concept, which has been proposed for calibrating high-resolution imaging radars. It modulates the radar signal in a manner that the retransmitted signals can be separated from the scene echoes. As wind farms often occupy only a small area, mitigation processing in the whole radar operation will be redundant and cost inefficient. Hence, this paper uses a transponder to determine whether the radar is impacted by the wind farms. If so, the effects of wind farms are then mitigated with subsequent Kalman filtering or plot target extraction algorithms. Taking airborne synthetic aperture radar (SAR) and pulse Doppler radar as the examples, this paper provides the corresponding system configuration and processing algorithms. The effectiveness of the mitigation technique is validated by numerical simulation results. PMID:24385880

  15. Detecting and Mitigating Wind Turbine Clutter for Airspace Radar Systems

    PubMed Central

    2013-01-01

    It is well recognized that a wind turbine has a large radar cross-section (RCS) and, due to the movement of the blades, the wind turbine will generate a Doppler frequency shift. This scattering behavior may cause severe interferences on existing radar systems including static ground-based radars and spaceborne or airborne radars. To resolve this problem, efficient techniques or algorithms should be developed to mitigate the effects of wind farms on radars. Herein, one transponder-based mitigation technique is presented. The transponder is not a new concept, which has been proposed for calibrating high-resolution imaging radars. It modulates the radar signal in a manner that the retransmitted signals can be separated from the scene echoes. As wind farms often occupy only a small area, mitigation processing in the whole radar operation will be redundant and cost inefficient. Hence, this paper uses a transponder to determine whether the radar is impacted by the wind farms. If so, the effects of wind farms are then mitigated with subsequent Kalman filtering or plot target extraction algorithms. Taking airborne synthetic aperture radar (SAR) and pulse Doppler radar as the examples, this paper provides the corresponding system configuration and processing algorithms. The effectiveness of the mitigation technique is validated by numerical simulation results. PMID:24385880

  16. Detecting and mitigating wind turbine clutter for airspace radar systems.

    PubMed

    Wang, Wen-Qin

    2013-01-01

    It is well recognized that a wind turbine has a large radar cross-section (RCS) and, due to the movement of the blades, the wind turbine will generate a Doppler frequency shift. This scattering behavior may cause severe interferences on existing radar systems including static ground-based radars and spaceborne or airborne radars. To resolve this problem, efficient techniques or algorithms should be developed to mitigate the effects of wind farms on radars. Herein, one transponder-based mitigation technique is presented. The transponder is not a new concept, which has been proposed for calibrating high-resolution imaging radars. It modulates the radar signal in a manner that the retransmitted signals can be separated from the scene echoes. As wind farms often occupy only a small area, mitigation processing in the whole radar operation will be redundant and cost inefficient. Hence, this paper uses a transponder to determine whether the radar is impacted by the wind farms. If so, the effects of wind farms are then mitigated with subsequent Kalman filtering or plot target extraction algorithms. Taking airborne synthetic aperture radar (SAR) and pulse Doppler radar as the examples, this paper provides the corresponding system configuration and processing algorithms. The effectiveness of the mitigation technique is validated by numerical simulation results.

  17. Airborne laser sensors and integrated systems

    NASA Astrophysics Data System (ADS)

    Sabatini, Roberto; Richardson, Mark A.; Gardi, Alessandro; Ramasamy, Subramanian

    2015-11-01

    The underlying principles and technologies enabling the design and operation of airborne laser sensors are introduced and a detailed review of state-of-the-art avionic systems for civil and military applications is presented. Airborne lasers including Light Detection and Ranging (LIDAR), Laser Range Finders (LRF), and Laser Weapon Systems (LWS) are extensively used today and new promising technologies are being explored. Most laser systems are active devices that operate in a manner very similar to microwave radars but at much higher frequencies (e.g., LIDAR and LRF). Other devices (e.g., laser target designators and beam-riders) are used to precisely direct Laser Guided Weapons (LGW) against ground targets. The integration of both functions is often encountered in modern military avionics navigation-attack systems. The beneficial effects of airborne lasers including the use of smaller components and remarkable angular resolution have resulted in a host of manned and unmanned aircraft applications. On the other hand, laser sensors performance are much more sensitive to the vagaries of the atmosphere and are thus generally restricted to shorter ranges than microwave systems. Hence it is of paramount importance to analyse the performance of laser sensors and systems in various weather and environmental conditions. Additionally, it is important to define airborne laser safety criteria, since several systems currently in service operate in the near infrared with considerable risk for the naked human eye. Therefore, appropriate methods for predicting and evaluating the performance of infrared laser sensors/systems are presented, taking into account laser safety issues. For aircraft experimental activities with laser systems, it is essential to define test requirements taking into account the specific conditions for operational employment of the systems in the intended scenarios and to verify the performance in realistic environments at the test ranges. To support the

  18. Ice island detection and characterization with airborne synthetic aperture radar

    SciTech Connect

    Jeffries, M.O.; Sackinger, W.M. )

    1990-04-15

    A 1:300,000 scale airborne synthetic aperture radar (SAR) image of an area of the Arctic Ocean adjacent to the Queen Elizabeth Islands, Canadian High Arctic, is examined to determine the number and characteristics of ice islands in the image and to assess the capability of airborne and satellite SAR to detect ice islands. Twelve ice islands have been identified, and their dimensions range from as large as 5.7 km by 8.7 km to as small as 0.15 km by 0.25 km. A significant SAR characteristic of the shelf ice portions of ice islands is a return with a ribbed texture of alternating lighter and darker grey tones resulting from the indulating shelf ice surfaces of the ice islands. The appearance of the ribbed texture varies according to the ice islands' orientation relative to the illumination direction and consequently the incidence angle. Some ice islands also include extensive areas of textureless dark tone attached to the shelf ice. The weak returns correspond to (1) multiyear landfast sea ice that was attached to the front of the Ward Hunt Ice Shelf at the time of calving and which has remained attached since then and (2) multiyear pack ice that has become attached and consolidated since the calving, indicating that ice islands can increase their area and mass significantly as they drift. Ice islands are easily discernible in SAR images and for the future SAR represents a promising technique to obtain a census of ice islands in the Arctic Ocean. However, any SAR-based census probably will be conservative because ice islands smaller than 300-400 m across are likely to remain undetected, particularly in areas of heavy ice ridging which produces strong SAR clutter.

  19. Indoor experimental facility for airborne synthetic aperture radar (SAR) configurations - rail-SAR

    NASA Astrophysics Data System (ADS)

    Kirose, Getachew; Phelan, Brian R.; Sherbondy, Kelly D.; Ranney, Kenneth I.; Koenig, Francois; Narayanan, Ram M.

    2014-05-01

    The Army Research Laboratory (ARL) is developing an indoor experimental facility to evaluate and assess airborne synthetic-aperture-radar-(SAR)-based detection capabilities. The rail-SAR is located in a multi-use facility that also provides a base for research and development in the area of autonomous robotic navigation. Radar explosive hazard detection is one key sensordevelopment area to be investigated at this indoor facility. In particular, the mostly wooden, multi-story building houses a two (2) story housing structure and an open area built over a large sandbox. The housing structure includes reconfigurable indoor walls which enable the realization of multiple See-Through-The-Wall (STTW) scenarios. The open sandbox, on the other hand, allows for surface and buried explosive hazard scenarios. The indoor facility is not rated for true explosive hazard materials so all targets will need to be inert and contain surrogate explosive fills. In this paper we discuss the current system status and describe data collection exercises conducted using canonical targets and frequencies that may be of interest to designers of ultra-wideband (UWB) airborne, ground penetrating SAR systems. A bi-static antenna configuration will be used to investigate the effects of varying airborne SAR parameters such as depression angle, bandwidth, and integration angle, for various target types and deployment scenarios. Canonical targets data were used to evaluate overall facility capabilities and limitations. These data is analyzed and summarized for future evaluations. Finally, processing techniques for dealing with RF multi-path and RFI due to operating inside the indoor facility are described in detail. Discussion of this facility and its capabilities and limitations will provide the explosive hazard community with a great airborne platform asset for sensor to target assessment.

  20. The Coplane Analysis Technique for Three-Dimensional Wind Retrieval Using the HIWRAP Airborne Doppler Radar

    NASA Technical Reports Server (NTRS)

    Didlake, Anthony C., Jr.; Heymsfield, Gerald M.; Tian, Lin; Guimond, Stephen R.

    2015-01-01

    The coplane analysis technique for mapping the three-dimensional wind field of precipitating systems is applied to the NASA High Altitude Wind and Rain Airborne Profiler (HIWRAP). HIWRAP is a dual-frequency Doppler radar system with two downward pointing and conically scanning beams. The coplane technique interpolates radar measurements to a natural coordinate frame, directly solves for two wind components, and integrates the mass continuity equation to retrieve the unobserved third wind component. This technique is tested using a model simulation of a hurricane and compared to a global optimization retrieval. The coplane method produced lower errors for the cross-track and vertical wind components, while the global optimization method produced lower errors for the along-track wind component. Cross-track and vertical wind errors were dependent upon the accuracy of the estimated boundary condition winds near the surface and at nadir, which were derived by making certain assumptions about the vertical velocity field. The coplane technique was then applied successfully to HIWRAP observations of Hurricane Ingrid (2013). Unlike the global optimization method, the coplane analysis allows for a transparent connection between the radar observations and specific analysis results. With this ability, small-scale features can be analyzed more adequately and erroneous radar measurements can be identified more easily.

  1. Airborne and spaceborne radar images for geologic and environmental mapping in the Amazon rain forest, Brazil

    NASA Technical Reports Server (NTRS)

    Ford, John P.; Hurtak, James J.

    1986-01-01

    Spaceborne and airborne radar image of portions of the Middle and Upper Amazon basin in the state of Amazonas and the Territory of Roraima are compared for purposes of geological and environmental mapping. The contrasted illumination geometries and imaging parameters are related to terrain slope and surface roughness characteristics for corresponding areas that were covered by each of the radar imaging systems. Landforms range from deeply dissected mountain and plateau with relief up to 500 m in Roraima, revealing ancient layered rocks through folded residual mountains to deeply beveled pediplain in Amazonas. Geomorphic features provide distinct textural signatures that are characteristic of different rock associations. The principle drainages in the areas covered are the Rio Negro, Rio Branco, and the Rio Japura. Shadowing effects and low radar sensitivity to subtle linear fractures that are aligned parallel or nearly parallel to the direction of radar illumination illustrate the need to obtain multiple coverage with viewing directions about 90 degrees. Perception of standing water and alluvial forest in floodplains varies with incident angle and with season. Multitemporal data sets acquired over periods of years provide an ideal method of monitoring environmental changes.

  2. Retrieval of Snow and Rain From Combined X- and W-B and Airborne Radar Measurements

    NASA Technical Reports Server (NTRS)

    Liao, Liang; Meneghini, Robert; Tian, Lin; Heymsfield, Gerald M.

    2008-01-01

    Two independent airborne dual-wavelength techniques, based on nadir measurements of radar reflectivity factors and Doppler velocities, respectively, are investigated with respect to their capability of estimating microphysical properties of hydrometeors. The data used to investigate the methods are taken from the ER-2 Doppler radar (X-band) and Cloud Radar System (W-band) airborne Doppler radars during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment campaign in 2002. Validity is assessed by the degree to which the methods produce consistent retrievals of the microphysics. For deriving snow parameters, the reflectivity-based technique has a clear advantage over the Doppler-velocity-based approach because of the large dynamic range in the dual-frequency ratio (DFR) with respect to the median diameter Do and the fact that the difference in mean Doppler velocity at the two frequencies, i.e., the differential Doppler velocity (DDV), in snow is small relative to the measurement errors and is often not uniquely related to Do. The DFR and DDV can also be used to independently derive Do in rain. At W-band, the DFR-based algorithms are highly sensitive to attenuation from rain, cloud water, and water vapor. Thus, the retrieval algorithms depend on various assumptions regarding these components, whereas the DDV-based approach is unaffected by attenuation. In view of the difficulties and ambiguities associated with the attenuation correction at W-band, the DDV approach in rain is more straightforward and potentially more accurate than the DFR method.

  3. Analysis of side-looking airborne radar performance in the detection of search and rescue targets

    NASA Astrophysics Data System (ADS)

    Edwards, N. C., Jr.; Mazour, T. J.; Hover, G. L.; Osmer, S. R.

    1980-03-01

    Since September 1978 side-looking airborne radar (SLAR) detection data has been gathered in conjunction with visual detection experiments conducted by the U.S.C.G. R D Center. These are the first in a series of experiments designed to improve search planning guidance contained in the National Search and Rescue Manual. HC-130 aircraft, equipped with either the Airborne Oil Surveillance System (AOSS) or SLAR/radar image processor (SLAR/RIP) configuration of the AN/APS-94D SLAR, conducted controlled searches for life rafts, small boats, and 41 to 95 foot Coast Guard vessels in Block Island Sound or open ocean. Through the use of a microwave ranging system and SLAR data, the positions of searchers and targets were accurately reconstructed to facilitate the verification of detections on SLAR films or video tape. These data were used to evaluate the effects of environmental and controllable parameters on SLAR detection of the various target types. While the size of the data base did not permit conclusive, quantitative assessment of the effect which each parameter had on SLAR detection performance, general trends, in system performance were identified. Of the 11 parameters which were investigated, preliminary indications are that wind speed, image background, sea state, precipitation, altitude, antenna polarization, target size/composition, and lateral range all may significantly influence SLAR detection of search and rescue targets. Further data collection and analysis is planned to quantify the effects of these and any other significant parameters on SLAR performance.

  4. Systems and Methods for Radar Data Communication

    NASA Technical Reports Server (NTRS)

    Bunch, Brian (Inventor); Szeto, Roland (Inventor); Miller, Brad (Inventor)

    2013-01-01

    A radar information processing system is operable to process high bandwidth radar information received from a radar system into low bandwidth radar information that may be communicated to a low bandwidth connection coupled to an electronic flight bag (EFB). An exemplary embodiment receives radar information from a radar system, the radar information communicated from the radar system at a first bandwidth; processes the received radar information into processed radar information, the processed radar information configured for communication over a connection operable at a second bandwidth, the second bandwidth lower than the first bandwidth; and communicates the radar information from a radar system, the radar information communicated from the radar system at a first bandwidth.

  5. Wind Retrieval Algorithms for the IWRAP and HIWRAP Airborne Doppler Radars with Applications to Hurricanes

    NASA Technical Reports Server (NTRS)

    Guimond, Stephen Richard; Tian, Lin; Heymsfield, Gerald M.; Frasier, Stephen J.

    2013-01-01

    Algorithms for the retrieval of atmospheric winds in precipitating systems from downward-pointing, conically-scanning airborne Doppler radars are presented. The focus in the paper is on two radars: the Imaging Wind and Rain Airborne Profiler(IWRAP) and the High-altitude IWRAP (HIWRAP). The IWRAP is a dual-frequency (Cand Ku band), multi-beam (incidence angles of 30 50) system that flies on the NOAAWP-3D aircraft at altitudes of 2-4 km. The HIWRAP is a dual-frequency (Ku and Kaband), dual-beam (incidence angles of 30 and 40) system that flies on the NASA Global Hawk aircraft at altitudes of 18-20 km. Retrievals of the three Cartesian wind components over the entire radar sampling volume are described, which can be determined using either a traditional least squares or variational solution procedure. The random errors in the retrievals are evaluated using both an error propagation analysis and a numerical simulation of a hurricane. These analyses show that the vertical and along-track wind errors have strong across-track dependence with values of 0.25 m s-1 at nadir to 2.0 m s-1 and 1.0 m s-1 at the swath edges, respectively. The across-track wind errors also have across-track structure and are on average, 3.0 3.5 m s-1 or 10 of the hurricane wind speed. For typical rotated figure four flight patterns through hurricanes, the zonal and meridional wind speed errors are 2 3 m s-1.Examples of measured data retrievals from IWRAP during an eyewall replacement cycle in Hurricane Isabel (2003) and from HIWRAP during the development of Tropical Storm Matthew (2010) are shown.

  6. Radar systems for a polar mission, volume 1

    NASA Technical Reports Server (NTRS)

    Moore, R. K.; Claassen, J. P.; Erickson, R. L.; Fong, R. K. T.; Komen, M. J.; Mccauley, J.; Mcmillan, S. B.; Parashar, S. K.

    1977-01-01

    The application of synthetic aperture radar (SAR) in monitoring and managing earth resources is examined. Synthetic aperture radars form a class of side-looking airborne radar, often referred to as coherent SLAR, which permits fine-resolution radar imagery to be generated at long operating ranges by the use of signal processing techniques. By orienting the antenna beam orthogonal to the motion of the spacecraft carrying the radar, a one-dimensional imagery ray system is converted into a two-dimensional or terrain imaging system. The radar's ability to distinguish - or resolve - closely spaced transverse objects is determined by the length of the pulse. The transmitter components receivers, and the mixer are described in details.

  7. Airborne wireless communication systems, airborne communication methods, and communication methods

    DOEpatents

    Deaton, Juan D.; Schmitt, Michael J.; Jones, Warren F.

    2011-12-13

    An airborne wireless communication system includes circuitry configured to access information describing a configuration of a terrestrial wireless communication base station that has become disabled. The terrestrial base station is configured to implement wireless communication between wireless devices located within a geographical area and a network when the terrestrial base station is not disabled. The circuitry is further configured, based on the information, to configure the airborne station to have the configuration of the terrestrial base station. An airborne communication method includes answering a 911 call from a terrestrial cellular wireless phone using an airborne wireless communication system.

  8. The pulse-pair algorithm as a robust estimator of turbulent weather spectral parameters using airborne pulse Doppler radar

    NASA Technical Reports Server (NTRS)

    Baxa, Ernest G., Jr.; Lee, Jonggil

    1991-01-01

    The pulse pair method for spectrum parameter estimation is commonly used in pulse Doppler weather radar signal processing since it is economical to implement and can be shown to be a maximum likelihood estimator. With the use of airborne weather radar for windshear detection, the turbulent weather and strong ground clutter return spectrum differs from that assumed in its derivation, so the performance robustness of the pulse pair technique must be understood. Here, the effect of radar system pulse to pulse phase jitter and signal spectrum skew on the pulse pair algorithm performance is discussed. Phase jitter effect may be significant when the weather return signal to clutter ratio is very low and clutter rejection filtering is attempted. The analysis can be used to develop design specifications for airborne radar system phase stability. It is also shown that the weather return spectrum skew can cause a significant bias in the pulse pair mean windspeed estimates, and that the poly pulse pair algorithm can reduce this bias. It is suggested that use of a spectrum mode estimator may be more appropriate in characterizing the windspeed within a radar range resolution cell for detection of hazardous windspeed gradients.

  9. Airborne derivation of microburst alerts from ground-based Terminal Doppler Weather Radar information: A flight evaluation

    NASA Technical Reports Server (NTRS)

    Hinton, David A.

    1993-01-01

    An element of the NASA/FAA windshear program is the integration of ground-based microburst information on the flight deck, to support airborne windshear alerting and microburst avoidance. NASA conducted a windshear flight test program in the summer of 1991 during which airborne processing of Terminal Doppler Weather Radar (TDWR) data was used to derive microburst alerts. Microburst information was extracted from TDWR, transmitted to a NASA Boeing 737 in flight via data link, and processed to estimate the windshear hazard level (F-factor) that would be experienced by the aircraft in each microburst. The microburst location and F-factor were used to derive a situation display and alerts. The situation display was successfully used to maneuver the aircraft for microburst penetrations, during which atmospheric 'truth' measurements were made. A total of 19 penetrations were made of TDWR-reported microburst locations, resulting in 18 airborne microburst alerts from the TDWR data and two microburst alerts from the airborne reactive windshear detection system. The primary factors affecting alerting performance were spatial offset of the flight path from the region of strongest shear, differences in TDWR measurement altitude and airplane penetration altitude, and variations in microburst outflow profiles. Predicted and measured F-factors agreed well in penetrations near microburst cores. Although improvements in airborne and ground processing of the TDWR measurements would be required to support an airborne executive-level alerting protocol, the practicality of airborne utilization of TDWR data link data has been demonstrated.

  10. CARABAS - an airborne VHF SAR system

    SciTech Connect

    Larsson, B.; Frolined, P.O.; Gustavsson, A.

    1996-11-01

    There is an increasing interest in imaging radar systems operating at low frequencies, Examples of civilian and military applications are detection of stealth-designed man-made objects, targets hidden under foliage, biomass estimation, and penetration into glaciers or ground. CARABAS (Coherent All Radio Band Sensing) is a new airborne SAR system developed by FOA. It is designed for operation in the lowest part of the VHF band (20-90 NHz), using horizontal polarisation. This frequency region gives the system a good ability to penetrate vegetation and to some extent ground. CARABAS is the first known SAR sensor with a capability of diffraction limited imaging, i.e. a resolution in magnitude of the adopted wavelengths. A Sabreliner business jet aircraft is used as the airborne platform. Critical parts in the development have been the antenna system, the receiver and the processing algorithms. Based upon the experiences gained with CARABAS I a major system upgrade is now taking place. The new CARABAS II system is scheduled to fly in May 1996. This system is designed to give operational performance while CARABAS I was used to verify the feasibility. The first major field campaigns are planned for the second half of 1996. CARABAS II is jointly developed by FOA and Ericsson Microwave Systems AB in Sweden. This paper will give an overview of the system design and data collected with the current radar system, including some results for forested regions. The achieved system performance will be discussed, with a presentation of the major modifications made in the new CARABAS 11 system. 12 refs., 7 figs., 2 tabs.

  11. The 94 GHz MMW imaging radar system

    NASA Technical Reports Server (NTRS)

    Alon, Yair; Ulmer, Lon

    1993-01-01

    The 94 GHz MMW airborne radar system that provides a runway image in adverse weather conditions is now undergoing tests at Wright-Patterson Air Force Base (WPAFB). This system, which consists of a solid state FMCW transceiver, antenna, and digital signal processor, has an update rate of 10 times per second, 0.35x azimuth resolution and up to 3.5 meter range resolution. The radar B scope (range versus azimuth) image, once converted to C scope (elevation versus azimuth), is compatible with the standard TV presentation and can be displayed on the Head Up Display (HUD) or Head Down Display (HDD) to aid the pilot during landing and takeoff in limited visibility conditions.

  12. Gallium arsenide changes the shape of airborne radar

    NASA Astrophysics Data System (ADS)

    Nathanson, Harvey C.; Driver, Mike C.; Thomas, R. Noel

    1987-04-01

    An evaluation is made of the intrinsic properties and projected performance capabilities of GaAs ICs, with a view to the impact of their use on military radars and such other electronic devices as wideband low noise amplifiers, power amplifiers, broadband phase shifters, and electronic attenuators. For these, GaAs offers higher electron velocity for high frequencies, broader bandwidth, and higher RF efficiency than other semiconductor technologies. The complexity of GaAs power monolithics has been doubling every nine months, and systems-on-a-wafer are expected to become available as IC yields increase. GaAs CCD imagers and memories will combine on-chip image scanning with monolithic microwave ICs for ultrahigh speed image processing.

  13. Mapping diverse forest cover with multipolarization airborne radar

    NASA Technical Reports Server (NTRS)

    Ford, J. P.; Wickland, D. E.; Sharitz, R. R.

    1985-01-01

    Imaging radar backscatter in continuously forested areas contains information about the forest canopy; it also contains data about topography, landforms, and terrain texture. For purposes of radar image interpretation and geologic mapping researchers were interested in identifying and separating forest canopy effects from geologic or geomorphic effects on radar images. The objectives of this investigation was to evaluate forest canopy variables in multipolarization radar images under conditions where geologic and topographic variables are at a minimum. A subsidiary objective was to compare the discriminatory capabilities of the radar images with corresponding optical images of similar spatial resolution. It appears that the multipolarization images discriminate variation in tree density, but no evidence was found for discrimination between evergreen and deciduous forest types.

  14. Airborne system for testing multispectral reconnaissance technologies

    NASA Astrophysics Data System (ADS)

    Schmitt, Dirk-Roger; Doergeloh, Heinrich; Keil, Heiko; Wetjen, Wilfried

    1999-07-01

    There is an increasing demand for future airborne reconnaissance systems to obtain aerial images for tactical or peacekeeping operations. Especially Unmanned Aerial Vehicles (UAVs) equipped with multispectral sensor system and with real time jam resistant data transmission capabilities are of high interest. An airborne experimental platform has been developed as testbed to investigate different concepts of reconnaissance systems before their application in UAVs. It is based on a Dornier DO 228 aircraft, which is used as flying platform. Great care has been taken to achieve the possibility to test different kinds of multispectral sensors. Hence basically it is capable to be equipped with an IR sensor head, high resolution aerial cameras of the whole optical spectrum and radar systems. The onboard equipment further includes system for digital image processing, compression, coding, and storage. The data are RF transmitted to the ground station using technologies with high jam resistance. The images, after merging with enhanced vision components, are delivered to the observer who has an uplink data channel available to control flight and imaging parameters.

  15. Measurements of Ocean Surface Scattering Using an Airborne 94-GHz Cloud Radar: Implication for Calibration of Airborne and Spaceborne W-band Radars

    NASA Technical Reports Server (NTRS)

    Li, Li-Hua; Heymsfield, Gerald M.; Tian, Lin; Racette, Paul E.

    2004-01-01

    Scattering properties of the Ocean surface have been widely used as a calibration reference for airborne and spaceborne microwave sensors. However, at millimeter-wave frequencies, the ocean surface backscattering mechanism is still not well understood, in part, due to the lack of experimental measurements. During the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE), measurements of ocean surface backscattering were made using a 94-GHz (W-band) cloud radar onboard a NASA ER-2 high-altitude aircraft. The measurement set includes the normalized Ocean surface cross section over a range of the incidence angles under a variety of wind conditions. Analysis of the radar measurements shows good agreement with a quasi-specular scattering model. This unprecedented dataset enhances our knowledge about the Ocean surface scattering mechanism at 94 GHz. The results of this work support the proposition of using the Ocean surface as a calibration reference for airborne millimeter-wave cloud radars and for the ongoing NASA CloudSat mission, which will use a 94-GHz spaceborne cloud radar for global cloud measurements.

  16. Feasibility of inter-comparing airborne and spaceborne observations of radar backscattering coefficients

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper investigates the feasibility of using an airborne synthetic aperture radar (SAR) to validate spaceborne SAR data. This is directed at soil moisture sensing and the recently launched Soil Moisture Active Passive (SMAP) satellite. The value of this approach is related to the fact that vicar...

  17. Airborne seeker evaluation and test system

    NASA Astrophysics Data System (ADS)

    Jollie, William B.

    1991-08-01

    The Airborne Seeker Evaluation Test System (ASETS) is an airborne platform for development, test, and evaluation of air-to-ground seekers and sensors. ASETS consists of approximately 10,000 pounds of equipment, including sixteen racks of control, display, and recording electronics, and a very large stabilized airborne turret, all carried by a modified C- 130A aircraft. The turret measures 50 in. in diameter and extends over 50 in. below the aircraft. Because of the low ground clearance of the C-130, a unique retractor mechanism was designed to raise the turret inside the aircraft for take-offs and landings, and deploy the turret outside the aircraft for testing. The turret has over 7 cubic feet of payload space and can accommodate up to 300 pounds of instrumentation, including missile seekers, thermal imagers, infrared mapping systems, laser systems, millimeter wave radar units, television cameras, and laser rangers. It contains a 5-axis gyro-stabilized gimbal system that will maintain a line of sight in the pitch, roll, and yaw axes to an accuracy better than +/- 125 (mu) rad. The rack-mounted electronics in the aircraft cargo bay can be interchanged to operate any type of sensor and record the data. Six microcomputer subsystems operate and maintain all of the system components during a test mission. ASETS is capable of flying at altitudes between 200 and 20,000 feet, and at airspeeds ranging from 100 to 250 knots. Mission scenarios can include air-to-surface seeker testing, terrain mapping, surface target measurement, air-to-air testing, atmospheric transmission studies, weather data collection, aircraft or missile tracking, background signature measurements, and surveillance. ASETS is fully developed and available to support test programs.

  18. Analysis and improved design considerations for airborne pulse Doppler radar signal processing in the detection of hazardous windshear

    NASA Technical Reports Server (NTRS)

    Lee, Jonggil

    1990-01-01

    High resolution windspeed profile measurements are needed to provide reliable detection of hazardous low altitude windshear with an airborne pulse Doppler radar. The system phase noise in a Doppler weather radar may degrade the spectrum moment estimation quality and the clutter cancellation capability which are important in windshear detection. Also the bias due to weather return Doppler spectrum skewness may cause large errors in pulse pair spectral parameter estimates. These effects are analyzed for the improvement of an airborne Doppler weather radar signal processing design. A method is presented for the direct measurement of windspeed gradient using low pulse repetition frequency (PRF) radar. This spatial gradient is essential in obtaining the windshear hazard index. As an alternative, the modified Prony method is suggested as a spectrum mode estimator for both the clutter and weather signal. Estimation of Doppler spectrum modes may provide the desired windshear hazard information without the need of any preliminary processing requirement such as clutter filtering. The results obtained by processing a NASA simulation model output support consideration of mode identification as one component of a windshear detection algorithm.

  19. Airborne profiling of ice thickness using a short pulse radar

    NASA Technical Reports Server (NTRS)

    Vickers, R. S.; Heighway, J. E.; Gedney, R.

    1973-01-01

    The acquisition and interpretation of ice thickness data from a mobile platform has for some time been a goal of the remote sensing community. Such data, once obtainable, is of value in monitoring the changes in ice thickness over large areas, and in mapping the potential hazards to traffic in shipping lanes. Measurements made from a helicopter-borne ice thickness profiler of ice in Lake Superior, Lake St. Clair and the St. Clair river as part of NASA's program to develop an ice information system are described. The profiler described is a high resolution, non-imaging, short pulse radar, operating at a carrier frequency of 2.7 GHz. The system can resolve reflective surfaces separated by as little as 10 cm. and permits measurement of the distance between resolvable surfaces with an accuracy of about 1 cm. Data samples are given for measurements both in a static (helicopter hovering), and a traverse mode. Ground truth measurements taken by an ice auger team traveling with the helicopter are compared with the remotely sensed data and the accuracy of the profiler is discussed based on these measurements.

  20. EcoSAR: NASA's P-band fully polarimetric single pass interferometric airborne radar

    NASA Astrophysics Data System (ADS)

    Osmanoglu, B.; Rincon, R. F.; Fatoyinbo, T. E.; Lee, S. K.; Sun, G.; Daniyan, O.; Harcum, M. E.

    2014-12-01

    EcoSAR is a new airborne synthetic aperture radar imaging system, developed at the NASA Goddard Space Flight Center. It is a P-band sensor that employs a non-conventional and innovative design. The EcoSAR system was designed as a multi-disciplinary instrument to image the 3-dimensional surface of the earth from a single pass platform with two antennas. EcoSAR's principal mission is to penetrate the forest canopy to return vital information about the canopy structure and estimate biomass. With a maximum bandwidth of 200 MHz in H and 120 MHz in V polarizations it can provide sub-meter resolution imagery of the study area. EcoSAR's dual antenna, 32 transmit and receive channel architecture provides a test-bed for developing new algorithms in InSAR data processing such as single pass interferometry, full polarimetry, post-processing synthesis of multiple beams, simultaneous measurement over both sides of the flight track, selectable resolution and variable incidence angle. The flexible architecture of EcoSAR will create new opportunities in radar remote sensing of forest biomass, permafrost active layer thickness, and topography mapping. EcoSAR's first test flight occurred between March 27th and April 1st, 2014 over the Andros Island in Bahamas and Corcovado and La Selva National Parks in Costa Rica. The 32 channel radar system collected about 6 TB of radar data in about 12 hours of data collection. Due to the existence of radio and TV communications in the operational frequency band, acquired data contains strong radar frequency interference, which had to be removed prior to beamforming and focusing. Precise locations of the antennas are tracked using high-rate GPS and inertial navigation units, which provide necessary information for accurate processing of the imagery. In this presentation we will present preliminary imagery collected during the test campaign, show examples of simultaneous dual track imaging, as well as a single pass interferogram. The

  1. NASA experimental airborne doppler radar and real time processor for wind shear detection

    NASA Technical Reports Server (NTRS)

    Schaffner, Philip H.; Richards, Mark A.; Jones, William R.; Crittenden, Lucille H.

    1992-01-01

    The topics are presented in viewgraph form and include the following: experimental radar system capabilities; an experimental radar system block diagram; wind shear radar signal and data processor (WRSDP); WRSDP hardware architecture; WRSDP system design goals; DSP software development tools; OS-9 software development tools; WRSDP digital signal processing; WRSDP display operational modes; WRSDP division of functions; structure of WRSDP signal and data processing algorithms; and the wind shear radar flight experiment.

  2. Airborne Ground Penetrating Radar (GPR) for peat analyses in the Canadian Northern wetlands study

    NASA Technical Reports Server (NTRS)

    Pelletier-Travis, Ramona E.

    1991-01-01

    The study was conducted as part of the NASA Biospherics Research on Emissions from Wetlands (BREW) program. An important aspect of the program is to investigate the terrestrial production and atmospheric distribution of methane and other gases contributing to global warming. Multi-kilometer transects of airborne (helicopter) Ground Penetrating Radar (GPR) data were collected periodically along the 100 km distance from the coast inland so as to obtain a regional trend in peat depth and related parameters. Global Positioning System (GPS) data were simultaneously collected from the helicopter to properly georeference the GPR data. Additional 50 m ground-based transects of GPR data were also collected as a source of ground truthing, as a calibration aid for the airborne data sets, and as a source of higher resolution data for characterizing the strata within the peat. In situ peat depth probing and soil characterizations from excavated soil pits were used to verify GPR findings. Results from the ground-based data are presented.

  3. GeoSAR: A Radar Terrain Mapping System for the New Millennium

    NASA Technical Reports Server (NTRS)

    Thompson, Thomas; vanZyl, Jakob; Hensley, Scott; Reis, James; Munjy, Riadh; Burton, John; Yoha, Robert

    2000-01-01

    GeoSAR Geographic Synthetic Aperture Radar) is a new 3 year effort to build a unique, dual-frequency, airborne Interferometric SAR for mapping of terrain. This is being pursued via a Consortium of the Jet Propulsion Laboratory (JPL), Calgis, Inc., and the California Department of Conservation. The airborne portion of this system will operate on a Calgis Gulfstream-II aircraft outfitted with P- and X-band Interferometric SARs. The ground portions of this system will be a suite of Flight Planning Software, an IFSAR Processor and a Radar-GIS Workstation. The airborne P-band and X-band radars will be constructed by JPL with the goal of obtaining foliage penetration at the longer P-band wavelengths. The P-band and X-band radar will operate at frequencies of 350 Mhz and 9.71 Ghz with bandwidths of either 80 or 160 Mhz. The airborne radars will be complemented with airborne laser system for measuring antenna positions. Aircraft flight lines and radar operating instructions will be computed with the Flight Planning Software The ground processing will be a two-step step process. First, the raw radar data will be processed into radar images and interferometer derived Digital Elevation Models (DEMs). Second, these radar images and DEMs will be processed with a Radar GIS Workstation which performs processes such as Projection Transformations, Registration, Geometric Adjustment, Mosaicking, Merging and Database Management. JPL will construct the IFSAR Processor and Calgis, Inc. will construct the Radar GIS Workstation. The GeoSAR Project was underway in November 1996 with a goal of having the radars and laser systems fully integrated onto the Calgis Gulfstream-II aircraft in early 1999. Then, Engineering Checkout and Calibration-Characterization Flights will be conducted through November 1999. The system will be completed at the end of 1999 and ready for routine operations in the year 2000.

  4. Electromagnetic Model Reliably Predicts Radar Scattering Characteristics of Airborne Organisms

    PubMed Central

    Mirkovic, Djordje; Stepanian, Phillip M.; Kelly, Jeffrey F.; Chilson, Phillip B.

    2016-01-01

    The radar scattering characteristics of aerial animals are typically obtained from controlled laboratory measurements of a freshly harvested specimen. These measurements are tedious to perform, difficult to replicate, and typically yield only a small subset of the full azimuthal, elevational, and polarimetric radio scattering data. As an alternative, biological applications of radar often assume that the radar cross sections of flying animals are isotropic, since sophisticated computer models are required to estimate the 3D scattering properties of objects having complex shapes. Using the method of moments implemented in the WIPL-D software package, we show for the first time that such electromagnetic modeling techniques (typically applied to man-made objects) can accurately predict organismal radio scattering characteristics from an anatomical model: here the Brazilian free-tailed bat (Tadarida brasiliensis). The simulated scattering properties of the bat agree with controlled measurements and radar observations made during a field study of bats in flight. This numerical technique can produce the full angular set of quantitative polarimetric scattering characteristics, while eliminating many practical difficulties associated with physical measurements. Such a modeling framework can be applied for bird, bat, and insect species, and will help drive a shift in radar biology from a largely qualitative and phenomenological science toward quantitative estimation of animal densities and taxonomic identification. PMID:27762292

  5. Venus Radar Mapper (VRM): Multimode radar system design

    NASA Technical Reports Server (NTRS)

    Johnson, William T. K.; Edgerton, Alvin T.

    1986-01-01

    The surface of Venus has remained a relative mystery because of the very dense atmosphere that is opaque to visible radiation and, thus, normal photographic techniques used to explore the other terrestrial objects in the solar system are useless. The atmosphere is, however, almost transparent to radar waves and images of the surface have been produced via Earth-based and orbital radars. The technique of obtaining radar images of a surface is variously called side looking radar, imaging radar, or synthetic aperture radar (SAR). The radar requires a moving platform in which the antenna is side looking. High resolution is obtained in the cross-track or range direction by conventional radar pulse encoding. In the along-track or azimuth direction, the resolution would normally be the antenna beam width, but for the SAR case, a much longer antenna (or much sharper beam) is obtained by moving past a surface target as shown, and then combining the echoes from many pulses, by using the Doppler data, to obtain the images. The radar design of the Venus Radar Mapper (VRM) is discussed. It will acquire global radar imagery and altimetry data of the surface of Venus.

  6. Geophex airborne unmanned survey system

    SciTech Connect

    Won, I.J.; Taylor, D.W.A.

    1995-03-01

    The purpose of this effort is to design, construct, and evaluate a portable, remotely-piloted, airborne, geophysical survey system. This nonintrusive system will provide {open_quotes}stand-off{close_quotes} capability to conduct surveys and detect buried objects, structures, and conditions of interest at hazardous locations. This system permits two operators to rapidly conduct geophysical characterization of hazardous environmental sites. During a survey, the operators remain remote from, but within visual distance, of, the site. The sensor system never contacts the Earth, but can be positioned near the ground so that weak anomalies can be detected.

  7. Geophex Airborne Unmanned Survey System

    SciTech Connect

    Won, I.J.; Keiswetter, D.

    1995-10-01

    The purpose of this effort is to design, construct, and evaluate a portable, remotely-piloted, airborne, geophysical survey system. This non-intrusive system will provide {open_quotes}stand-off{close_quotes} capability to conduct surveys and detect buried objects, structures, and conditions of interest at hazardous locations. This system permits rapid geophysical characterization of hazardous environmental sites. During a survey, the operators remain remote from, but within visual distance of, the site. The sensor system never contacts the Earth, but can be positioned near the ground so that weak geophysical anomalies can be detected.

  8. Airborne In Situ and Ground-based Polarimetric Radar Measurements of Tropical Convection in Support of CRYSTAL-FACE

    NASA Technical Reports Server (NTRS)

    Poellot, Michael R.; Kucera, Paul A.

    2004-01-01

    This report describes the work performed by the University of North Dakota (UND) under NASA Grant NAG5-11509, titled Airborne In Situ and Ground-based Polarimetric Radar Measurements of Tropical Convection in Support of CRYSTAL-FACE. This work focused on the collection of data by two key platforms: the UND Citation II research aircraft and the NASA NPOL radar system. The CRYSTAL-FACE (C-F) mission addresses several key issues from the NASA Earth System Enterprise, including the variability of water in the atmosphere, the forcing provided by tropical cirrus and the response of the Earth system to this forcing. In situ measurements and radar observations of tropical convection, cirrus clouds and their environment are core elements of C-F. One of the primary issues that C-F is addressing is the relationship of tropical cirrus anvils to precipitating deep convection. The in situ measurements from C-F are being used to validate remote sensing of Earth-Atmosphere properties, increase our knowledge of upper tropospheric water vapor and its distribution, and increase our knowledge of tropical cirrus cloud morphology and composition. Radar measurements, especially polarimetric diversity observations available fiom the NASA NPOL radar, are providing essential information about the initiation, modulation, and dissipation of convective cores and the generation of associated anvils in tropical convection. Specifically, NPOL radar measurements contain information about convective intensity and its vertical structure for comparison with thermodynamic and kinematic environmental measurements observed from soundings. Because of the polarimetric diversity of MOL, statistics on bulk microphysical properties can be retrieved and compared to the other characteristics of convection and associated cirrus anvils. In summary, the central objectives of this proposal were to deploy the UND Citation research aircraft as an in situ sensing platform for this mission and to provide collaborative

  9. Flight investigation of helicopter IFR approaches to oil rigs using airborne weather and mapping radar

    NASA Technical Reports Server (NTRS)

    Bull, J. S.; Hegarty, D. M.; Phillips, J. D.; Sturgeon, W. R.; Hunting, A. W.; Pate, D. P.

    1979-01-01

    Airborne weather and mapping radar is a near-term, economical method of providing 'self-contained' navigation information for approaches to offshore oil rigs and its use has been rapidly expanding in recent years. A joint NASA/FAA flight test investigation of helicopter IFR approaches to offshore oil rigs in the Gulf of Mexico was initiated in June 1978 and conducted under contract to Air Logistics. Approximately 120 approaches were flown in a Bell 212 helicopter by 15 operational pilots during the months of August and September 1978. The purpose of the tests was to collect data to (1) support development of advanced radar flight director concepts by NASA and (2) aid the establishment of Terminal Instrument Procedures (TERPS) criteria by the FAA. The flight test objectives were to develop airborne radar approach procedures, measure tracking errors, determine accpetable weather minimums, and determine pilot acceptability. Data obtained will contribute significantly to improved helicopter airborne radar approach capability and to the support of exploration, development, and utilization of the Nation's offshore oil supplies.

  10. Polarization differences in airborne ground penetrating radar performance for landmine detection

    NASA Astrophysics Data System (ADS)

    Dogaru, Traian; Le, Calvin

    2016-05-01

    The U.S. Army Research Laboratory (ARL) has investigated the ultra-wideband (UWB) radar technology for detection of landmines, improvised explosive devices and unexploded ordnance, for over two decades. This paper presents a phenomenological study of the radar signature of buried landmines in realistic environments and the performance of airborne synthetic aperture radar (SAR) in detecting these targets as a function of multiple parameters: polarization, depression angle, soil type and burial depth. The investigation is based on advanced computer models developed at ARL. The analysis includes both the signature of the targets of interest and the clutter produced by rough surface ground. Based on our numerical simulations, we conclude that low depression angles and H-H polarization offer the highest target-to-clutter ratio in the SAR images and therefore the best radar performance of all the scenarios investigated.

  11. Characterization of wetland, forest, and agricultural ecosystems in Belize with airborne radar (AIRSAR)

    NASA Technical Reports Server (NTRS)

    Pope, Kevin O.; Rey-Benayas, Jose Maria; Paris, Jack F.

    1992-01-01

    The Shuttle Imaging Radar-C/X-SAR (Synthetic Aperture Radar) Experiment includes the study of wetland dynamics in the seasonal tropics. In preparation for these wetland studies, airborne P, L, and C band radar (AIRSAR) data of Belize, Guatemala, and Mexico acquired by NASA and JPL in March 1990 were analyzed. The first phase of our study focuses on AIRSAR data from the Gallon Jug test site in northwestern Belize, for which ground data were also collected during the three days prior to the overflight. One of the main objectives of the Gallon Jug study is to develop a method for characterizing wetland vegetation types and their flooding status with multifrequency polarimetric radar data.

  12. Greenland annual accumulation along the EGIG line, 1959-2004, from ASIRAS airborne radar and neutron-probe density measurements

    NASA Astrophysics Data System (ADS)

    Overly, Thomas B.; Hawley, Robert L.; Helm, Veit; Morris, Elizabeth M.; Chaudhary, Rohan N.

    2016-08-01

    We report annual snow accumulation rates from 1959 to 2004 along a 250 km segment of the Expéditions Glaciologiques Internationales au Groenland (EGIG) line across central Greenland using Airborne SAR/Interferometric Radar Altimeter System (ASIRAS) radar layers and high resolution neutron-probe (NP) density profiles. ASIRAS-NP-derived accumulation rates are not statistically different (95 % confidence interval) from in situ EGIG accumulation measurements from 1985 to 2004. ASIRAS-NP-derived accumulation increases by 20 % below 3000 m elevation, and increases by 13 % above 3000 m elevation for the period 1995 to 2004 compared to 1985 to 1994. Three Regional Climate Models (PolarMM5, RACMO2.3, MAR) underestimate snow accumulation below 3000 m by 16-20 % compared to ASIRAS-NP from 1985 to 2004. We test radar-derived accumulation rates sensitivity to density using modeled density profiles in place of NP densities. ASIRAS radar layers combined with Herron and Langway (1980) model density profiles (ASIRAS-HL) produce accumulation rates within 3.5 % of ASIRAS-NP estimates in the dry snow region. We suggest using Herron and Langway (1980) density profiles to calibrate radar layers detected in dry snow regions of ice sheets lacking detailed in situ density measurements, such as those observed by the Operation IceBridge campaign.

  13. Towards a Semantic Interpretation of Urban Areas with Airborne Synthetic Aperture Radar Tomography

    NASA Astrophysics Data System (ADS)

    D'Hondt, O.; Guillaso, S.; Hellwich, O.

    2016-06-01

    In this paper, we introduce a method to detect and reconstruct building parts from tomographic Synthetic Aperture Radar (SAR) airborne data. Our approach extends recent works in two ways: first, the radiometric information is used to guide the extraction of geometric primitives. Second, building facades and roofs are extracted thanks to geometric classification rules. We demonstrate our method on a 3 image L-Band airborne dataset over the city of Dresden, Germany. Experiments show how our technique allows to use the complementarity between the radiometric image and the tomographic point cloud to extract buildings parts in challenging situations.

  14. Goldstone solar system radar

    NASA Technical Reports Server (NTRS)

    Jurgens, Raymond F.

    1991-01-01

    Caltech/Jet Propulsion Laboratory (JPL) radar astronomers made use of the Very Large Array (VLA) at Socorro, NM, during February 1990, to receive radio echoes from the planet Venus. The transmitter was the 70 meter antenna at the Goldstone complex northwest of Barstow, CA. These observations contain new information about the roughness of Venus at cm to decimeter scales and are complementary to information being obtained by the Magellan spacecraft. Asteroid observations are also discussed.

  15. Multi-frequency fine resolution imaging radar instrumentation and data acquisition. [side-looking radar for airborne imagery

    NASA Technical Reports Server (NTRS)

    Rendleman, R. A.; Champagne, E. B.; Ferris, J. E.; Liskow, C. L.; Marks, J. M.; Salmer, R. J.

    1974-01-01

    Development of a dual polarized L-band radar imaging system to be used in conjunction with the present dual polarized X-band radar is described. The technique used called for heterodyning the transmitted frequency from X-band to L-band and again heterodyning the received L-band signals back to X-band for amplification, detection, and recording.

  16. Radar altimetry systems cost analysis

    NASA Technical Reports Server (NTRS)

    Escoe, D.; Heuring, F. T.; Denman, W. F.

    1976-01-01

    This report discusses the application and cost of two types of altimeter systems (spaceborne (satellite and shuttle) and airborne) to twelve user requirements. The overall design of the systems defined to meet these requirements is predicated on an unconstrained altimetry technology; that is, any level of altimeter or supporting equipment performance is possible.

  17. Geophex Airborne Unmanned Survey System

    SciTech Connect

    Won, I.L.; Keiswetter, D.

    1995-12-31

    Ground-based surveys place personnel at risk due to the proximity of buried unexploded ordnance (UXO) items or by exposure to radioactive materials and hazardous chemicals. The purpose of this effort is to design, construct, and evaluate a portable, remotely-piloted, airborne, geophysical survey system. This non-intrusive system will provide stand-off capability to conduct surveys and detect buried objects, structures, and conditions of interest at hazardous locations. During a survey, the operators remain remote from, but within visual distance of, the site. The sensor system never contacts the Earth, but can be positioned near the ground so that weak geophysical anomalies can be detected. The Geophex Airborne Unmanned Survey System (GAUSS) is designed to detect and locate small-scale anomalies at hazardous sites using magnetic and electromagnetic survey techniques. The system consists of a remotely-piloted, radio-controlled, model helicopter (RCH) with flight computer, light-weight geophysical sensors, an electronic positioning system, a data telemetry system, and a computer base-station. The report describes GAUSS and its test results.

  18. 77 FR 37470 - Technical Standard Order (TSO)-C65a, Airborne Doppler Radar Ground Speed and/or Drift Angle...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-21

    ... Federal Aviation Administration Technical Standard Order (TSO)-C65a, Airborne Doppler Radar Ground Speed... Doppler radar ground speed and/or drift angle measuring equipment (for air carrier aircraft). SUMMARY: This notice announces the FAA's intent to cancel TSO-C65a, Airborne Doppler radar ground speed...

  19. Clutter filter design considerations for Airborne Doppler radar detection of windshear

    NASA Technical Reports Server (NTRS)

    Baxa, Ernest G., Jr.

    1990-01-01

    The problem of clutter rejection when processing down-looking Doppler radar returns from a low altitude airborne platform is a paramount problem. With radar as a remote sensor for detecting and predicting windshear in the vicinity of an urban airport, dynamic range requirements can exceed 50 dB because of high clutter to signal ratios. This presentation describes signal processing considerations in the presence of distributed and/or discrete clutter interference. Previous analyses have considered conventional range cell processing of radar returns from a rigidly mounted radar platform using either the Fourier or the pulse-pair method to estimate average windspeed and windspeed variation within a cell. Clutter rejection has been based largely upon analyzing a particular environment in the vicinity of the radar and employing a variety of techniques to reduce interference effects including notch filtering, Fourier domain line editing, and use of clutter maps. For the airborne environment the clutter characteristics may be somewhat different. Conventional clutter rejection methods may have to be changed and new methods will probably be required to provide useful signal to noise ratios. Various considerations are described. A major thrust has been to evaluate the effect of clutter rejection filtering upon the ability to derive useful information from the post-filter radar data. This analysis software is briefly described. Finally, some ideas for future analysis are considered including the use of adaptive filtering for clutter rejection and the estimation of windspeed spatial gradient directly from radar returns as a means of reducing the effects of clutter on the determination of a windshear hazard.

  20. Hydrometeor Profiles Derived from Airborne Radar and Wideband Radiometer Observations

    NASA Technical Reports Server (NTRS)

    Skofronick-Jackson, G. M.; Wang, J. R.; Heymsfield, G.; Hood, R.; Arnold, James E. (Technical Monitor)

    2000-01-01

    A rich dataset was obtained with observations from the MIR (Millimeter-wave Imaging Radiometer, 89, 150, 183.3$\\pm$1, 183.3$\\pm$3,183.3$\\pm$7, and 220 apprx.GHz), the AMPR (Advanced Microwave Precipitation Radiometer, 10.7, 19.35, 37, and 85 approx. GHz), and the EDOP (ER-2 Doppler Radar, 9.6 approx. GHz) on board the ER-2 aircraft during the CAMEX-3/TEFLUN-B (Convection and Moisture Experiment/Texas and Florida Underflights) TRMM (Tropical Rainfall Measuring Mission) field campaign. Measurements over the ocean from these three instruments on 26 August 1998 were used in our iterative retrieval algorithm to estimate hydrometeor drop size profiles, The algorithm attempts to minimize the difference between the observations and forward radiometer and radar calculations based on the estimated profile. The high frequency MIR observations provide detailed information about the high altitude ice microphysics, while the AMPR is mostly used to define liquid hydrometeor characteristics. The EDOP provides an initial estimate of the profile and as a consistency check throughout the iterative cycle. The retrieval algorithm, specific results for convective and anvil cases, and general implications of this work will be presented.

  1. Preliminary results from multiparameter airborne rain radar measurement in the western Pacific

    NASA Technical Reports Server (NTRS)

    Kumagai, Hiroshi; Meneghini, Robert; Kozu, Toshiaki

    1993-01-01

    Preliminary results are presented from multiparameter airborne radar measurements of tropical storms. The experiment was conducted in the western Pacific in September 1990 with the NASA DC-8 aircraft that was equipped with a dual-wavelength radar at X and Ka bands and several microwave radiometers. The modification to dual-polarization at X-band radar enabled measurements of the linear depolarization ratio (LDR). Vertical profiles of dual-polarization and dual-frequency observables for an example of stratiform rain and three examples of convective rain cells are examined. It is shown that at nadir incidence the LDR measurement often can be used to distinguish the phase states of the hydrometeors and to identify the melting layer. In addition to the information concerning particle shape and orientation from LDR, the ratio of the radar reflectivity factors in two frequency bands (X and Ka bands) provides insight into particle size. The capabilities of dual-wavelength and dual-polarization radar in the identification of particle size and phase will be important considerations in the design of future spaceborne weather radars.

  2. Preliminary Results from Multiparameter Airborne Rain Radar Measurement in the Western Pacific.

    NASA Astrophysics Data System (ADS)

    Kumagai, Hiroshi; Meneghini, Robert; Kozu, Toshiaki

    1993-02-01

    Preliminary results are presented from multiparameter airborne radar measurements of tropical storms. The experiment was conducted in the western Pacific in September 1990 with the NASA DC-8 aircraft that was equipped with a dual-wavelength radar at X and Ka bands and several microwave radiometers. The modification to dual-polarization at X-band radar enabled measurements of the linear depolarization ratio (LDR). Vertical profiles of dual-polarization and dual-frequency observables for an example of stratiform rain and three examples of convective rain cells are examined. It is shown that at nadir incidence the LDR measurement often can be used to distinguish the phase states of the hydrometeors and to identify the melting layer. In addition to the information concerning particle shape and orientation from LDR, the ratio of the radar reflectivity factors in two frequency bands (X and Ka bands) provides insight into particle size. The capabilities of dual-wavelength and dual-polarization radar in the identification of particle size and phase will be important considerations in the design of future spaceborne weather radars.

  3. Annual Greenland accumulation rates (2009-2012) from airborne snow radar

    NASA Astrophysics Data System (ADS)

    Koenig, Lora S.; Ivanoff, Alvaro; Alexander, Patrick M.; MacGregor, Joseph A.; Fettweis, Xavier; Panzer, Ben; Paden, John D.; Forster, Richard R.; Das, Indrani; McConnell, Joesph R.; Tedesco, Marco; Leuschen, Carl; Gogineni, Prasad

    2016-08-01

    Contemporary climate warming over the Arctic is accelerating mass loss from the Greenland Ice Sheet through increasing surface melt, emphasizing the need to closely monitor its surface mass balance in order to improve sea-level rise predictions. Snow accumulation is the largest component of the ice sheet's surface mass balance, but in situ observations thereof are inherently sparse and models are difficult to evaluate at large scales. Here, we quantify recent Greenland accumulation rates using ultra-wideband (2-6.5 GHz) airborne snow radar data collected as part of NASA's Operation IceBridge between 2009 and 2012. We use a semiautomated method to trace the observed radiostratigraphy and then derive annual net accumulation rates for 2009-2012. The uncertainty in these radar-derived accumulation rates is on average 14 %. A comparison of the radar-derived accumulation rates and contemporaneous ice cores shows that snow radar captures both the annual and long-term mean accumulation rate accurately. A comparison with outputs from a regional climate model (MAR) shows that this model matches radar-derived accumulation rates in the ice sheet interior but produces higher values over southeastern Greenland. Our results demonstrate that snow radar can efficiently and accurately map patterns of snow accumulation across an ice sheet and that it is valuable for evaluating the accuracy of surface mass balance models.

  4. An airborne, real aperture radar study of the Chesapeake Bay outflow plume

    NASA Astrophysics Data System (ADS)

    Sletten, Mark A.; Marmorino, George O.; Donato, Tim F.; McLaughlin, David J.; Twarog, Elizabeth

    1999-01-01

    An airborne, real aperture radar (RAR) has been used to study the fronts associated with the Chesapeake Bay outflow plume during spring outflow conditions. The RAR produced images of the ocean surface with a range resolution of 10 m, an azimuthal resolution of approximately 30 m, and an image size of 2.5 km × 24 km. Two sampling strategies were utilized: one to synoptically map the entire mouth of the Chesapeake Bay at roughly hourly intervals; and a second to capture the rapid evolution of particular features. In addition, flight times were chosen such that over the course of the entire experiment, data were collected over all phases of the semidiurnal tidal cycle. Three distinct frontal signatures were observed in the imagery. A primary front extended from inside the estuary along the Chesapeake Channel to an anticyclonic turning region east of Cape Henry, and then extended southward along the coast toward Cape Hatteras. This is the classic expression of the plume front, inertial turning region, and coastal jet. A second front with a north-south orientation was observed approximately 20 km east of the bay mouth. This secondary front appears to mark the residual offshore density gradient. A third front was identified east and south of Cape Henry, within 2 km of the coast. This front appears to mark the inshore edge of the plume and has not been documented previously. Time sequences of the imagery indicate that when moving in a clockwise sense around the primary front, the frontal translation speed varies systematically from 20 cm/s in the northern section to 50 cm/s in the south. The position of the primary front and the locations and trajectories of small-scale frontal cusps suggest that bathymetry may be both a significant determinant of the front location as well as a source of along-front variability. These observations are possible due to the airborne RAR's ability to collect high-frame rate image sequences, a capability that is not shared by present space

  5. Goldstone solar system radar signal processing

    NASA Technical Reports Server (NTRS)

    Jurgens, R.; Satorius, E.; Sanchez, O.

    1992-01-01

    A performance analysis of the planetary radar data acquisition system is presented. These results extend previous computer simulation analysis and are facilitated by the development of a simple analytical model that predicts radar system performance over a wide range of operational parameters. The results of this study are useful to both the radar system designer and the science investigator in establishing operational radar data acquisition parameters which result in the best systems performance for a given set of input conditions.

  6. Goldstone solar system radar signal processing

    NASA Technical Reports Server (NTRS)

    Jurgens, R. F.; Satorius, E.; Sanchez, O.

    1992-01-01

    A performance analysis of the planetary radar data acquisition system is presented. These results extend previous computer simulation analysis and are facilitated by the development of a simple analytical model that predicts radar system performance over a wide range of operational parameters. The results of this study are useful to both the radar systems designer and the science investigator in establishing operational radar data acquisition parameters which result in the best systems performance for a given set of input conditions.

  7. Airborne Relay-Based Regional Positioning System

    PubMed Central

    Lee, Kyuman; Noh, Hongjun; Lim, Jaesung

    2015-01-01

    Ground-based pseudolite systems have some limitations, such as low vertical accuracy, multipath effects and near-far problems. These problems are not significant in airborne-based pseudolite systems. However, the monitoring of pseudolite positions is required because of the mobility of the platforms on which the pseudolites are mounted, and this causes performance degradation. To address these pseudolite system limitations, we propose an airborne relay-based regional positioning system that consists of a master station, reference stations, airborne relays and a user. In the proposed system, navigation signals are generated from the reference stations located on the ground and are relayed via the airborne relays. Unlike in conventional airborne-based systems, the user in the proposed system sequentially estimates both the locations of airborne relays and his/her own position. Therefore, a delay due to monitoring does not occur, and the accuracy is not affected by the movement of airborne relays. We conducted several simulations to evaluate the performance of the proposed system. Based on the simulation results, we demonstrated that the proposed system guarantees a higher accuracy than airborne-based pseudolite systems, and it is feasible despite the existence of clock offsets among reference stations. PMID:26029953

  8. Spectrum Modal Analysis for the Detection of Low-Altitude Windshear with Airborne Doppler Radar

    NASA Technical Reports Server (NTRS)

    Kunkel, Matthew W.

    1992-01-01

    A major obstacle in the estimation of windspeed patterns associated with low-altitude windshear with an airborne pulsed Doppler radar system is the presence of strong levels of ground clutter which can strongly bias a windspeed estimate. Typical solutions attempt to remove the clutter energy from the return through clutter rejection filtering. Proposed is a method whereby both the weather and clutter modes present in a return spectrum can be identified to yield an unbiased estimate of the weather mode without the need for clutter rejection filtering. An attempt will be made to show that modeling through a second order extended Prony approach is sufficient for the identification of the weather mode. A pattern recognition approach to windspeed estimation from the identified modes is derived and applied to both simulated and actual flight data. Comparisons between windspeed estimates derived from modal analysis and the pulse-pair estimator are included as well as associated hazard factors. Also included is a computationally attractive method for estimating windspeeds directly from the coefficients of a second-order autoregressive model. Extensions and recommendations for further study are included.

  9. UAVSAR - A New Airborne L-Band Radar for Repeat Pass Interferometry

    NASA Technical Reports Server (NTRS)

    Mace, Thomas H.; Lou, Yunling

    2009-01-01

    NASA/JPL has developed a new airborne Synthetic Aperture Radar (SAR) which has become available for use by the scientific community in January, 2009. Pod mounted, the UAVSAR was designed to be portable among a variety of aircraft, including unmanned aerial systems (UAS). The instrument operates in the L-Band, has a resolution under 2m from a GPS altitude of 12Km and a swath width of approximately 20Km. UAVSAR currently flies on a modified Gulfstream-III aircraft, operated by NASA s Dryden Flight Research Center at Edwards, California. The G-III platform enables repeat-pass interferometric measurements, by using a modified autopilot and precise kinematic differential GPS to repeatedly fly the aircraft within a specified 10m tube. The antenna is electronically steered along track to assure that the antenna beam can be directed independently, regardless of speed and wind direction. The instrument can be controlled remotely, AS AN OPTION, using the Research Environment for Vehicle Embedded Analysis on Linux (REVEAL). This allows simulation of the telepresence environment necessary for flight on UAS. Potential earth science research and applications include surface deformation, volcano studies, ice sheet dynamics, and vegetation structure.

  10. Algorithm of geometry correction for airborne 3D scanning laser radar

    NASA Astrophysics Data System (ADS)

    Liu, Yuan; Chen, Siying; Zhang, Yinchao; Ni, Guoqiang

    2009-11-01

    Airborne three-dimensional scanning laser radar is used for wholesale scanning exploration to the target realm, then three-dimensional model can be established and target features can be identified with the characteristics of echo signals. So it is used widely and have bright prospect in the modern military, scientific research, agriculture and industry. At present, most researchers are focus on higher precision, more reliability scanning system. As the scanning platform is fixed on the aircraft, the plane cannot keep horizontal for a long time, also impossibly for a long time fly in the route without deviation. Data acquisition and the subsequence calibration rely on different equipments. These equipments bring errors both in time and space. Accurate geometry correction can amend the errors created by the process of assembly. But for the errors caused by the plane during the flight, whole imaging process should be analyzed. Take the side-roll as an example; scanning direction is inclined, so that the scanning point deviates from the original place. New direction and coordinate is the aim to us. In this paper, errors caused by the side-roll, pitch, yaw and assembly are analyzed and the algorithm routine is designed.

  11. Investigation of Advanced Radar Techniques for Atmospheric Hazard Detection with Airborne Weather Radar

    NASA Technical Reports Server (NTRS)

    Pazmany, Andrew L.

    2014-01-01

    In 2013 ProSensing Inc. conducted a study to investigate the hazard detection potential of aircraft weather radars with new measurement capabilities, such as multi-frequency, polarimetric and radiometric modes. Various radar designs and features were evaluated for sensitivity, measurement range and for detecting and quantifying atmospheric hazards in wide range of weather conditions. Projected size, weight, power consumption and cost of the various designs were also considered. Various cloud and precipitation conditions were modeled and used to conduct an analytic evaluation of the design options. This report provides an overview of the study and summarizes the conclusions and recommendations.

  12. Obstacle penetrating dynamic radar imaging system

    DOEpatents

    Romero, Carlos E.; Zumstein, James E.; Chang, John T.; Leach, Jr.. Richard R.

    2006-12-12

    An obstacle penetrating dynamic radar imaging system for the detection, tracking, and imaging of an individual, animal, or object comprising a multiplicity of low power ultra wideband radar units that produce a set of return radar signals from the individual, animal, or object, and a processing system for said set of return radar signals for detection, tracking, and imaging of the individual, animal, or object. The system provides a radar video system for detecting and tracking an individual, animal, or object by producing a set of return radar signals from the individual, animal, or object with a multiplicity of low power ultra wideband radar units, and processing said set of return radar signals for detecting and tracking of the individual, animal, or object.

  13. A geologic analysis of the Side-Looking Airborne Radar imagery of southern New England

    USGS Publications Warehouse

    Banks, Paul T.

    1975-01-01

    Analysis of the side looking airborn radar imagery of Massachusetts, Connecticut and Rhode Island indicates that radar shows the topography in great detail. Since bedrock geologic features are frequently expressed in the topography the radar lends itself to geologic interpretation. The radar was studied by comparisons with field mapped geologic data first at a scale of approximately 1:125,000 and then at a scale of 1:500,000. The larger scale comparison revealed that faults, minor faults, joint sets, bedding and foliation attitudes, lithology and lithologic contacts all have a topographic expression interpretable on the imagery. Surficial geologic features were far less visible on the imagery over most of the area studied. The smaller scale comparisons revealed a pervasive, near orthogonal fracture set cutting all types and ages of rock and trending roughly N40?E and N30?W. In certain places the strike of bedding and foliation attitudes and some lithologic Contacts were visible in addition to the fractures. Fracturing in southern New England is apparently far more important than has been previously recognized. This new information, together with the visibility of many bedding and foliation attitudes and lithologic contacts, indicates the importance of radar imagery in improving the geologic interpretation of an area.

  14. Annual Greenland Accumulation Rates (2009-2012) from Airborne Snow Radar

    NASA Technical Reports Server (NTRS)

    Koenig, Lora S.; Ivanoff, Alvaro; Alexander, Patrick M.; MacGregor, Joseph A.; Fettweis, Xavier; Panzer, Ben; Paden, John D.; Forster, Richard R.; Das, Indrani; McConnell, Joseph R.; Tedesco, Marco; Leuschen, Carl; Gogineni, Prasad

    2016-01-01

    Contemporary climate warming over the Arctic is accelerating mass loss from the Greenland Ice Sheet through increasing surface melt, emphasizing the need to closely monitor its surface mass balance in order to improve sea-level rise predictions. Snow accumulation is the largest component of the ice sheet's surface mass balance, but in situ observations thereof are inherently sparse and models are difficult to evaluate at large scales. Here, we quantify recent Greenland accumulation rates using ultra-wideband (2-6.5 gigahertz) airborne snow radar data collected as part of NASA's Operation IceBridge between 2009 and 2012. We use a semi-automated method to trace the observed radiostratigraphy and then derive annual net accumulation rates for 2009-2012. The uncertainty in these radar-derived accumulation rates is on average 14 percent. A comparison of the radarderived accumulation rates and contemporaneous ice cores shows that snow radar captures both the annual and longterm mean accumulation rate accurately. A comparison with outputs from a regional climate model (MAR - Modele Atmospherique Regional for Greenland and vicinity) shows that this model matches radar-derived accumulation rates in the ice sheet interior but produces higher values over southeastern Greenland. Our results demonstrate that snow radar can efficiently and accurately map patterns of snow accumulation across an ice sheet and that it is valuable for evaluating the accuracy of surface mass balance models.

  15. A comparison of airborne and ground-based radar observations with rain gages during the CaPE experiment

    NASA Technical Reports Server (NTRS)

    Satake, Makoto; Short, David A.; Iguchi, Toshio

    1992-01-01

    The vicinity of KSC, where the primary ground truth site of the Tropical Rainfall Measuring Mission (TRMM) program is located, was the focal point of the Convection and Precipitation/Electrification (CaPE) experiment in Jul. and Aug. 1991. In addition to several specialized radars, local coverage was provided by the C-band (5 cm) radar at Patrick AFB. Point measurements of rain rate were provided by tipping bucket rain gage networks. Besides these ground-based activities, airborne radar measurements with X- and Ka-band nadir-looking radars on board an aircraft were also recorded. A unique combination data set of airborne radar observations with ground-based observations was obtained in the summer convective rain regime of central Florida. We present a comparison of these data intending a preliminary validation. A convective rain event was observed simultaneously by all three instrument types on the evening of 27 Jul. 1991. The high resolution aircraft radar was flown over convective cells with tops exceeding 10 km and observed reflectivities of 40 to 50 dBZ at 4 to 5 km altitude, while the low resolution surface radar observed 35 to 55 dBZ echoes and a rain gage indicated maximum surface rain rates exceeding 100 mm/hr. The height profile of reflectivity measured with the airborne radar show an attenuation of 6.5 dB/km (two way) for X-band, corresponding to a rainfall rate of 95 mm/hr.

  16. A comparison of airborne and ground-based radar observations with rain gages during the CaPE experiment

    NASA Technical Reports Server (NTRS)

    Satake, Makoto; Short, David A.; Iguchi, Toshio

    1992-01-01

    The vicinity of KSC, where the primary ground truth site of the Tropical Rainfall Measuring Mission (TRMM) program is located, was the focal point of the Convection and Precipitation/Electrification (CaPE) experiment in July and Aug. 1991. In addition to several specialized radars, local coverage was provided by the C-band (5 cm) radar at Patrick AFB. Point measurements of rain rate were provided by tipping bucket rain gage networks. Besides these ground-based activities, airborne radar measurements with X- and Ka-band nadir-looking radars on board an aircraft were also recorded. A unique combination data set of airborne radar observations with ground-based observations was obtained in the summer convective rain regime of central Florida. We present a comparison of these data intending a preliminary validation. A convective rain event was observed simultaneously by all three instrument types on the evening of 27 July 1991. The high resolution aircraft radar was flown over convective cells with tops exceeding 10 km and observed reflectivities of 40 to 50 dBZ at 4 to 5 km altitude, while the low resolution surface radar observed 35 to 55 dBZ echoes and a rain gage indicated maximum surface rain rates exceeding 100 mm/hr. The height profile of reflectivity measured with the airborne radar show an attenuation of 6.5 dB/km (two way) for X-band, corresponding to a rainfall rate of 95 mm/hr.

  17. Analysis of Airborne Radar Altimetry Measurements of the Greenland Ice Sheet

    NASA Technical Reports Server (NTRS)

    Ferraro, Ellen J.

    1994-01-01

    This dissertation presents an analysis of airborne altimetry measurements taken over the Greenland ice sheet with the 13.9 GHz Advanced Application Flight Experiment (AAFE) pulse compression radar altimeter. This Ku-band instrument was refurbished in 1990 by the Microwave Remote Sensing Laboratory at the University of Massachusetts to obtain high-resolution altitude measurements and to improve the tracking, speed, storage and display capabilities of the radar. In 1991 and 1993, the AAFE altimeter took part in the NASA Multisensor Airborne Altimetry Experiments over Greenland, along with two NASA laser altimeters. Altitude results from both experiments are presented along with comparisons to the laser altimeter and calibration passes over the Sondrestroem runway in Greenland. Although it is too early to make a conclusion about the growth or decay of the ice sheet, these results show that the instrument is capable of measuring small-scale surface changes to within 14 centimeters. In addition, results from these experiments reveal that the radar is sensitive to the different diagenetic regions of the ice sheet. Return waveforms from the wet- snow, percolation and dry-snow zones show varying effects of both surface scattering and sub-surface or volume scattering. Models of each of the diagenetic regions of Greenland are presented along with parameters such as rms surface roughness, rms surface slope and attenuation coefficient of the snow pack obtained by fitting the models to actual return waveforms.

  18. Mars Radar Observations with the Goldstone Solar System Radar

    NASA Technical Reports Server (NTRS)

    Haldemann, A. F. C.; Jurgens, R. F.; Larsen, K. W.; Arvidson, R. E.; Slade, M. A.

    2002-01-01

    The Goldstone Solar System Radar (GSSR) has successfully collected radar echo data from Mars over the past 30 years. As such, the GSSR has played a role as a specific mission element within Mars exploration. The older data provided local elevation information for Mars, along with radar scattering information with global resolution. Since the upgrade to the 70-m Deep Space Network (DSN) antenna at Goldstone completed in 1986, Mars data has been collected during all but the 1997 Mars opposition. Radar data, and non-imaging delay-Doppler data in particular, requires significant data processing to extract elevation, reflectivity and roughness of the reflecting surface. The spatial resolution of these experiments is typically some 20 km in longitude by some 150 km in latitude. The interpretation of these parameters while limited by the complexities of electromagnetic scattering, do provide information directly relevant to geophysical and geomorphic analyses of Mars. The usefulness of radar data for Mars exploration has been demonstrated in the past. Radar data were critical in assessing the Viking Lander 1 site as well as, more recently, the Pathfinder landing site. In general, radar data have not been available to the Mars exploration community at large. A project funded initially by the Mars Exploration Directorate Science Office at the Jet Propulsion Laboratory (JPL), and later funded by NASA's Mars Data Analysis Program has reprocessed to a common format a decade's worth of raw GSSR Mars delay-Doppler data in aid of landing site characterization for the Mars Program. These data will soon be submitted to the Planetary Data System (PDS). The radar data used were obtained between 1988 and 1995 by the GSSR, and comprise some 63 delay-Doppler radar tracks. Of these, 15 have yet to be recovered from old 9-track tapes, and some of the data may be permanently lost.

  19. Monitoring by holographic radar systems

    NASA Astrophysics Data System (ADS)

    Catapano, Ilaria; Crocco, Lorenzo; Affinito, Antonio; Gennarelli, Gianluca; Soldovieri, Francesco

    2013-04-01

    Nowadays, radar technology represents a significant opportunity to collect useful information for the monitoring and conservation of critical infrastructures. Radar systems exploit the non-invasive interaction between the matter and the electromagnetic waves at microwave frequencies. Such an interaction allows obtaining images of the region under test from which one can infer the presence of potential anomalies such as deformations, cracks, water infiltrations, etc. This information turns out to be of primary importance in practical scenarios where the probed structure is in a poor state of preservation and renovation works must be planned. In this framework, the aim of this contribution is to describe the potentialities of the holographic radar Rascan 4/4000, a holographic radar developed by Remote Sensing Laboratory of Bauman Moscow State Technical University, as a non-destructive diagnostic tool capable to provide, in real-time, high resolution subsurface images of the sounded structure [1]. This radar provides holograms of hidden anomalies from the amplitude of the interference signal arising between the backscattered signal and a reference signal. The performance of the holographic radar is appraised by means of several experiments. Preliminary tests concerning the imaging below the floor and inside wood structures are carried out in controlled conditions at the Electromagnetic Diagnostic Laboratory of IREA-CNR. After, with reference to bridge monitoring for security aim, the results of a measurement campaign performed on the Musmeci bridge are presented [2]. Acknowledgments This research has been performed in the framework of the "Active and Passive Microwaves for Security and Subsurface imaging (AMISS)" EU 7th Framework Marie Curie Actions IRSES project (PIRSES-GA-2010-269157). REFERENCES [1] S. Ivashov, V. Razevig, I. Vasilyev, A. Zhuravlev, T. Bechtel, L. Capineri, The holographic principle in subsurface radar technology, International Symposium to

  20. Impacts of 4D-VAR Assimilation of Airborne Doppler Radar Observations on Numerical Simulations of the Genesis of Typhoon Nuri (2008)

    NASA Astrophysics Data System (ADS)

    Pu, Z.; Li, Z.

    2014-12-01

    The Weather Research and Forecasting model and its four-dimensional variational data assimilation system are employed to examine the impact of airborne Doppler radar observations on predicting the genesis of Typhoon Nuri (2008). The ELDORA airborne radar data, collected during the Office of Naval Research-sponsored Tropical Cyclone Structure 2008 field experiment, are used for data assimilation experiments. Two assimilation methods are evaluated and compared, namely, the direct assimilation of radar-measured radial velocity and the assimilation of three-dimensional wind analysis derived from the radar radial velocity. Results show that direct assimilation of radar radial velocity leads to better intensity forecasts, as it enhances the development of convective systems and improves the inner core structure of Nuri, whereas assimilation of the radar-retrieved wind analysis is more beneficial for tracking forecasts, as it results in improved environmental flows. The assimilation of both the radar-retrieved wind and the radial velocity can lead to better forecasts in both intensity and tracking, if the radial velocity observations are assimilated first and the retrieved winds are then assimilated in the same data assimilation window. In addition, experiments with and without radar data assimilation lead to developing and nondeveloping disturbances for Nuri's genesis in the numerical simulations. The improved initial conditions and forecasts from the data assimilation imply that the enhanced midlevel vortex and moisture conditions are favorable for the development of deep convection in the center of the pouch and eventually contribute to Nuri's genesis. The improved simulations of the convection and associated environmental conditions produce enhanced upper-level warming in the core region and lead to the drop in sea-level pressure.

  1. Goldstone Solar System Radar (GSSR)

    NASA Technical Reports Server (NTRS)

    Renzetti, N. A.

    1991-01-01

    The primary objective of the Goldstone Solar System Radar is the investigation of solar system bodies by means of Earth-based radar. Targets of primary interest include the Galilean moons, Saturn's rings and moons, and Earth-approaching asteroids and comets. Planets are also of interest, particularly Mercury and the planets to which NASA has not yet planned spacecraft visits. Based on a history of solid achievement, including the definition of the Astronomical Unit, imaging and topography of Mars, Venus, and Mercury, and contributions to the general theory of relativity, the program will continue to support flight project requirements and its primary objectives. The individual target objectives are presented, and information on the following topics are presented in tabular form: Deep Space Network support, compatibility tests, telemetry, command, and tracking support responsibility.

  2. A Methodology for Determining Statistical Performance Compliance for Airborne Doppler Radar with Forward-Looking Turbulence Detection Capability. Second Corrected Copy Issued May 23, 2011

    NASA Technical Reports Server (NTRS)

    Bowles, Roland L.; Buck, Bill K.

    2009-01-01

    The objective of the research developed and presented in this document was to statistically assess turbulence hazard detection performance employing airborne pulse Doppler radar systems. The FAA certification methodology for forward looking airborne turbulence radars will require estimating the probabilities of missed and false hazard indications under operational conditions. Analytical approaches must be used due to the near impossibility of obtaining sufficient statistics experimentally. This report describes an end-to-end analytical technique for estimating these probabilities for Enhanced Turbulence (E-Turb) Radar systems under noise-limited conditions, for a variety of aircraft types, as defined in FAA TSO-C134. This technique provides for one means, but not the only means, by which an applicant can demonstrate compliance to the FAA directed ATDS Working Group performance requirements. Turbulence hazard algorithms were developed that derived predictive estimates of aircraft hazards from basic radar observables. These algorithms were designed to prevent false turbulence indications while accurately predicting areas of elevated turbulence risks to aircraft, passengers, and crew; and were successfully flight tested on a NASA B757-200 and a Delta Air Lines B737-800. Application of this defined methodology for calculating the probability of missed and false hazard indications taking into account the effect of the various algorithms used, is demonstrated for representative transport aircraft and radar performance characteristics.

  3. Comparison of Retracking Algorithms Using Airborne Radar and Laser Altimeter Measurements of the Greenland Ice Sheet

    NASA Technical Reports Server (NTRS)

    Ferraro, Ellen J.; Swift, Calvin T.

    1995-01-01

    This paper compares four continental ice sheet radar altimeter retracking algorithms using airborne radar and laser altimeter data taken over the Greenland ice sheet in 1991. The refurbished Advanced Application Flight Experiment (AAFE) airborne radar altimeter has a large range window and stores the entire return waveform during flight. Once the return waveforms are retracked, or post-processed to obtain the most accurate altitude measurement possible, they are compared with the high-precision Airborne Oceanographic Lidar (AOL) altimeter measurements. The AAFE waveforms show evidence of varying degrees of both surface and volume scattering from different regions of the Greenland ice sheet. The AOL laser altimeter, however, obtains a return only from the surface of the ice sheet. Retracking altimeter waveforms with a surface scattering model results in a good correlation with the laser measurements in the wet and dry-snow zones, but in the percolation region of the ice sheet, the deviation between the two data sets is large due to the effects of subsurface and volume scattering. The Martin et al model results in a lower bias than the surface scattering model, but still shows an increase in the noise level in the percolation zone. Using an Offset Center of Gravity algorithm to retrack altimeter waveforms results in measurements that are only slightly affected by subsurface and volume scattering and, despite a higher bias, this algorithm works well in all regions of the ice sheet. A cubic spline provides retracked altitudes that agree with AOL measurements over all regions of Greenland. This method is not sensitive to changes in the scattering mechanisms of the ice sheet and it has the lowest noise level and bias of all the retracking methods presented.

  4. The application of airborne imaging radars (L and X-band) to earth resources problems

    NASA Technical Reports Server (NTRS)

    Drake, B.; Shuchman, R. A.; Bryan, M. L.; Larson, R. W.; Liskow, C. L.; Rendleman, R. A.

    1974-01-01

    A multiplexed synthetic aperture Side-Looking Airborne Radar (SLAR) that simultaneously images the terrain with X-band (3.2 cm) and L-band (23.0 cm) radar wavelengths was developed. The Feasibility of using multiplexed SLAR to obtain useful information for earth resources purposes. The SLAR imagery, aerial photographs, and infrared imagery are examined to determine the qualitative tone and texture of many rural land-use features imaged. The results show that: (1) Neither X- nor L-band SLAR at moderate and low depression angles can directly or indirectly detect pools of water under standing vegetation. (2) Many of the urban and rural land-use categories present in the test areas can be identified and mapped on the multiplexed SLAR imagery. (3) Water resources management can be done using multiplexed SLAR. (4) Drainage patterns can be determined on both the X- and L-band imagery.

  5. An Efficient Adaptive Angle-Doppler Compensation Approach for Non-Sidelooking Airborne Radar STAP

    PubMed Central

    Shen, Mingwei; Yu, Jia; Wu, Di; Zhu, Daiyin

    2015-01-01

    In this study, the effects of non-sidelooking airborne radar clutter dispersion on space-time adaptive processing (STAP) is considered, and an efficient adaptive angle-Doppler compensation (EAADC) approach is proposed to improve the clutter suppression performance. In order to reduce the computational complexity, the reduced-dimension sparse reconstruction (RDSR) technique is introduced into the angle-Doppler spectrum estimation to extract the required parameters for compensating the clutter spectral center misalignment. Simulation results to demonstrate the effectiveness of the proposed algorithm are presented. PMID:26053755

  6. An Efficient Adaptive Angle-Doppler Compensation Approach for Non-Sidelooking Airborne Radar STAP.

    PubMed

    Shen, Mingwei; Yu, Jia; Wu, Di; Zhu, Daiyin

    2015-06-04

    In this study, the effects of non-sidelooking airborne radar clutter dispersion on space-time adaptive processing (STAP) is considered, and an efficient adaptive angle-Doppler compensation (EAADC) approach is proposed to improve the clutter suppression performance. In order to reduce the computational complexity, the reduced-dimension sparse reconstruction (RDSR) technique is introduced into the angle-Doppler spectrum estimation to extract the required parameters for compensating the clutter spectral center misalignment. Simulation results to demonstrate the effectiveness of the proposed algorithm are presented.

  7. An Efficient Adaptive Angle-Doppler Compensation Approach for Non-Sidelooking Airborne Radar STAP.

    PubMed

    Shen, Mingwei; Yu, Jia; Wu, Di; Zhu, Daiyin

    2015-01-01

    In this study, the effects of non-sidelooking airborne radar clutter dispersion on space-time adaptive processing (STAP) is considered, and an efficient adaptive angle-Doppler compensation (EAADC) approach is proposed to improve the clutter suppression performance. In order to reduce the computational complexity, the reduced-dimension sparse reconstruction (RDSR) technique is introduced into the angle-Doppler spectrum estimation to extract the required parameters for compensating the clutter spectral center misalignment. Simulation results to demonstrate the effectiveness of the proposed algorithm are presented. PMID:26053755

  8. Airborne Wind Shear Detection and Warning Systems: Third Combined Manufacturers' and Technologists' Conference, part 1

    NASA Technical Reports Server (NTRS)

    Vicroy, Dan D. (Compiler); Bowles, Roland L. (Compiler); Schlickenmaier, Herbert (Compiler)

    1991-01-01

    Papers presented at the conference on airborne wind shear detection and warning systems are compiled. The following subject areas are covered: terms of reference; case study; flight management; sensor fusion and flight evaluation; Terminal Doppler Weather Radar data link/display; heavy rain aerodynamics; and second generation reactive systems.

  9. Surface Clutter Removal in Airborne Radar Sounding Data from the Dry Valleys, Antarctica

    NASA Technical Reports Server (NTRS)

    Holt, J. W.; Blankenship, D. D.; Morse, D. L.; Peters, M. E.; Kempf, S. D.

    2005-01-01

    We have collected roughly 1,000 line-km of airborne radar sounding data over glaciers, rock/ice glaciers, permafrost, subsurface ice bodies, ice-covered saline lakes, and glacial deposits in Taylor and Beacon Valley. These data are being analyzed in order to develop techniques for discriminating between subsurface and off-nadir echoes and for detecting and characterizing subsurface interfaces. The identification of features on Mars exhibiting morphologies consistent with ice/rock mixtures, near-surface ice bodies and near-surface liquid water, and the importance of such features to the search for water on Mars, highlights the need for appropriate terrestrial analogs and analysis techniques in order to prepare for radar sounder missions to Mars. Climatic, hydrological, and geological conditions in the Dry Valleys of Antarctica are analogous in many ways to those on Mars. A crucial first step in the data analysis process is the discrimination of echo sources in the radar data. The goal is to identify all returns from the surface of off-nadir topography in order to positively identify subsurface echoes. This process will also be critical for radar data that will be collected in areas of Mars exhibiting significant topography, so that subsurface echoes are identified unambiguously. The positive detection and characterization of subsurface (including sub-ice) water is a primary goal of NASA's Mars exploration program. Our data over the Dry Valleys provides an opportunity to implement techniques we are developing to accomplish these goals.

  10. Airborne laser scan data: a valuable tool with which to infer weather radar partial beam blockage in urban environments

    NASA Astrophysics Data System (ADS)

    Cremonini, Roberto; Moisseev, Dmitri; Chandrasekar, Venkatachalam

    2016-10-01

    High-spatial-resolution weather radar observations are of primary relevance for hydrological applications in urban areas. However, when weather radars are located within metropolitan areas, partial beam blockages and clutter by buildings can seriously affect the observations. Standard simulations with simple beam propagation models and digital elevation models (DEMs) are usually not able to evaluate buildings' contribution to partial beam blockages. In recent years airborne laser scanners (ALSs) have evolved to the state-of-the-art technique for topographic data acquisition. Providing small footprint diameters (10-30 cm), ALS data allow accurate reconstruction of buildings and forest canopy heights. Analyzing the three weather C-band radars located in the metropolitan area of Helsinki, Finland, the present study investigates the benefits of using ALS data for quantitative estimations of partial beam blockages. The results obtained applying beam standard propagation models are compared with stratiform 24 h rainfall accumulation to evaluate the effects of partial beam blockages due to constructions and trees. To provide a physical interpretation of the results, the detailed analysis of beam occultations is achieved by open spatial data sets and open-source geographic information systems.

  11. Airborne radar and radiometer experiment for quantitative remote measurements of rain

    NASA Technical Reports Server (NTRS)

    Kozu, Toshiaki; Meneghini, Robert; Boncyk, Wayne; Wilheit, Thomas T.; Nakamura, Kenji

    1989-01-01

    An aircraft experiment has been conducted with a dual-frequency (10 GHz and 35 GHz) radar/radiometer system and an 18-GHz radiometer to test various rain-rate retrieval algorithms from space. In the experiment, which took place in the fall of 1988 at the NASA Wallops Flight Facility, VA, both stratiform and convective storms were observed. A ground-based radar and rain gauges were also used to obtain truth data. An external radar calibration is made with rain gauge data, thereby enabling quantitative reflectivity measurements. Comparisons between path attenuations derived from the surface return and from the radar reflectivity profile are made to test the feasibility of a technique to estimate the raindrop size distribution from simultaneous radar and path-attenuation measurements.

  12. Integrated bias removal in passive radar systems

    NASA Astrophysics Data System (ADS)

    Subramaniam, M.; Punithakumar, K.; McDonald, M.; Kirubarajan, T.

    2008-04-01

    A passive coherent location (PCL) system exploits the ambient FM radio or television signals from powerful local transmitters, which makes it ideal for covert tracking. In a passive radar system, also known as PCL system, a variety of measurements can be used to estimate target states such as direction of arrival (DOA), time difference of arrival (TDOA) or Doppler shift. Noise and the precision of DOA estimation are main issues in a PCL system and methods such as conventional beam forming (CBF) algorithm, algebraic constant modulus algorithm (ACMA) are widely analyzed in literature to address them. In practical systems, although it is necessary to reduce the directional ambiguities, the placement of receivers closed to each other results in larger bias in the estimation of DOA of signals, especially when the targets move off bore-sight. This phenomenon leads to degradation in the performance of the tracking algorithm. In this paper, we present a method for removing the bias in DOA to alleviate the aforementioned problem. The simulation results are presented to show the effectiveness of the proposed algorithm with an example of tracking airborne targets.

  13. Downscaling of Airborne Wind Energy Systems

    NASA Astrophysics Data System (ADS)

    Fechner, Uwe; Schmehl, Roland

    2016-09-01

    Airborne wind energy systems provide a novel solution to harvest wind energy from altitudes that cannot be reached by wind turbines with a similar nominal generator power. The use of a lightweight but strong tether in place of an expensive tower provides an additional cost advantage, next to the higher capacity factor and much lower total mass. This paper investigates the scaling effects of airborne wind energy systems. The energy yield of airborne wind energy systems, that work in pumping mode of operation is at least ten times higher than the energy yield of conventional solar systems. For airborne wind energy systems the yield is defined per square meter wing area. In this paper the dependency of the energy yield on the nominal generator power for systems in the range of 1 kW to 1 MW is investigated. For the onshore location Cabauw, The Netherlands, it is shown, that a generator of just 1.4 kW nominal power and a total system mass of less than 30 kg has the theoretical potential to harvest energy at only twice the price per kWh of large scale airborne wind energy systems. This would make airborne wind energy systems a very attractive choice for small scale remote and mobile applications as soon as the remaining challenges for commercialization are solved.

  14. Echo Source Discrimination in Airborne Radar Sounding Data From the Dry Valleys, Antarctica, for Mars Analog Studies

    NASA Astrophysics Data System (ADS)

    Holt, J. W.; Blankenship, D. D.; Peters, M. E.; Kempf, S. D.; Williams, B. J.

    2003-12-01

    The identification of features on Mars exhibiting morphologies consistent with ice/rock mixtures, near-surface ice bodies and near-surface liquid water, and the importance of such features to the search for water on Mars highlights the need for appropriate terrestrial analogs in order to prepare for upcoming radar missions targeting these and other water-related features. Climatic, hydrological, and geological conditions in the McMurdo Dry Valleys of Antarctica are analogous in many ways to those on Mars, and a number of ice-related features in the Dry Valleys may have direct morphologic and compositional counterparts on Mars. We have collected roughly 1,000 line-km of airborne radar sounding data in the Dry Valleys for Mars analog studies. A crucial first step in the data analysis process is the discrimination of echo sources in the radar data. The goal is to identify all returns from the surface of surrounding topography in order to positively identify subsurface echoes. This process will also be critical for radar data that will be collected in areas of Mars exhibiting significant topography, so that subsurface echoes are identified unambiguously. Using a Twin Otter airborne platform, data were collected in three separate flights during the austral summers of 1999-2000 and 2001-2002 using multiple systems, including a chirped 52.5 - 67.5 MHz coherent radar operating at 750 W and 8 kW peak power (with multiple receivers) and 1 - 2 microsecond pulse width, and a 60 MHz pulsed, incoherent radar operating at 8 kW peak power with 60 ns and 250 ns pulse width. The chirped, coherent data are suitable for the implementation of advanced pulse compression algorithms and SAR focusing. Flight elevation was nominally 500 m above the surface. Targets included permafrost, subsurface ice bodies, rock/ice glaciers, ice-covered saline lakes, and glacial deposits in Taylor and Beacon Valleys. A laser altimeter (fixed relative to the aircraft frame) was also used during both

  15. Performance of convection-permitting hurricane initialization and prediction during 2008-2010 with ensemble data assimilation of inner-core airborne Doppler radar observations

    NASA Astrophysics Data System (ADS)

    Zhang, Fuqing; Weng, Yonghui; Gamache, John F.; Marks, Frank D.

    2011-08-01

    This study examines a hurricane prediction system that uses an ensemble Kalman filter (EnKF) to assimilate high-resolution airborne radar observations for convection-permitting hurricane initialization and forecasting. This system demonstrated very promising performance, especially on hurricane intensity forecasts, through experiments over all 61 applicable NOAA P-3 airborne Doppler missions during the 2008-2010 Atlantic hurricane seasons. The mean absolute intensity forecast errors initialized with the EnKF-analysis of the airborne Doppler observations at the 24- to 120-h lead forecast times were 20-40% lower than the National Hurricane Center's official forecasts issued at similar times. This prototype system was first implemented in real-time for Hurricane Ike (2008). It represents the first time that airborne Doppler radar observations were successfully assimilated in real-time into a hurricane prediction model. It also represents the first time that the convection-permitting ensemble analyses and forecasts for hurricanes were performed in real-time. Also unprecedented was the on-demand usage of more than 23,000 computer cluster processors simultaneously in real-time.

  16. Radar volcano monitoring system in Iceland

    NASA Astrophysics Data System (ADS)

    Arason, Þórður; Yeo, Richard F.; Sigurðsson, Geirfinnur S.; Pálmason, Bolli; von Löwis, Sibylle; Nína Petersen, Guðrún; Bjornsson, Halldór

    2013-04-01

    Weather radars are valuable instruments in monitoring explosive volcanic eruptions. Temporal variations in the eruption strength can be monitored as well as variations in plume and ash dispersal. Strength of the reflected radar signal of a volcanic plume is related to water content and droplet sizes as well as type, shape, amount and the grain size distribution of ash. The Icelandic Meteorological Office (IMO) owns and operates three radars and one more is planned for this radar volcano monitoring system. A fixed position 250 kW C-band weather radar was installed in 1991 in SW-Iceland close to Keflavík International Airport, and upgraded to a doppler radar in 2010. In cooperation with the International Civil Aviation Organization (ICAO), IMO has recently invested in two mobile X-band radars and one fixed position C-band radar. The fixed position 250 kW doppler C-band weather radar was installed in April 2012 at Fljótsdalsheiði, E-Iceland, and in June 2012 IMO received a mobile 65 kW dual-polarization doppler X-band radar. Early in 2013 IMO will acquire another mobile radar of the same type. Explosive volcanic eruptions in Iceland during the past 22 years were monitored by the Keflavík radar: Hekla 1991, Gjálp 1996, Grímsvötn 1998, Hekla 2000, Grímsvötn 2004, Eyjafjallajökull 2010 and Grímsvötn 2011. Additionally, the Grímsvötn 2011 eruption was mointored by a mobile X-band radar on loan from the Italian Civil Protection Authorities. Detailed technical information is presented on the four radars with examples of the information acquired during previous eruptions. This expanded network of radars is expected to give valuable information on future volcanic eruptions in Iceland.

  17. Application of Radar Data to Remote Sensing and Geographical Information Systems

    NASA Technical Reports Server (NTRS)

    vanZyl, Jakob J.

    2000-01-01

    The field of synthetic aperture radar changed dramatically over the past decade with the operational introduction of advance radar techniques such as polarimetry and interferometry. Radar polarimetry became an operational research tool with the introduction of the NASA/JPL AIRSAR system in the early 1980's, and reached a climax with the two SIR-C/X-SAR flights on board the space shuttle Endeavour in April and October 1994. Radar interferometry received a tremendous boost when the airborne TOPSAR system was introduced in 1991 by NASA/JPL, and further when data from the European Space Agency ERS-1 radar satellite became routinely available in 1991. Several airborne interferometric SAR systems are either currently operational, or are about to be introduced. Radar interferometry is a technique that allows one to map the topography of an area automatically under all weather conditions, day or night. The real power of radar interferometry is that the images and digital elevation models are automatically geometrically resampled, and could be imported into GIS systems directly after suitable reformatting. When combined with polarimetry, a technique that uses polarization diversity to gather more information about the geophysical properties of the terrain, a very rich multi-layer data set is available to the remote sensing scientist. This talk will discuss the principles of radar interferometry and polarimetry with specific application to the automatic categorization of land cover. Examples will include images acquired with the NASA/JPL AIRSAR/TOPSAR system in Australia and elsewhere.

  18. Multifunctional millimeter-wave radar system for helicopter safety

    NASA Astrophysics Data System (ADS)

    Goshi, Darren S.; Case, Timothy J.; McKitterick, John B.; Bui, Long Q.

    2012-06-01

    A multi-featured sensor solution has been developed that enhances the operational safety and functionality of small airborne platforms, representing an invaluable stride toward enabling higher-risk, tactical missions. This paper demonstrates results from a recently developed multi-functional sensor system that integrates a high performance millimeter-wave radar front end, an evidence grid-based integration processing scheme, and the incorporation into a 3D Synthetic Vision System (SVS) display. The front end architecture consists of a w-band real-beam scanning radar that generates a high resolution real-time radar map and operates with an adaptable antenna architecture currently configured with an interferometric capability for target height estimation. The raw sensor data is further processed within an evidence grid-based integration functionality that results in high-resolution maps in the region surrounding the platform. Lastly, the accumulated radar results are displayed in a fully rendered 3D SVS environment integrated with local database information to provide the best representation of the surrounding environment. The integrated system concept will be discussed and initial results from an experimental flight test of this developmental system will be presented. Specifically, the forward-looking operation of the system demonstrates the system's ability to produce high precision terrain mapping with obstacle detection and avoidance capability, showcasing the system's versatility in a true operational environment.

  19. Retrieve Optically Thick Ice Cloud Microphysical Properties by Using Airborne Dual-Wavelength Radar Measurements

    NASA Technical Reports Server (NTRS)

    Wang, Zhien; Heymsfield, Gerald M.; Li, Lihua; Heymsfield, Andrew J.

    2005-01-01

    An algorithm to retrieve optically thick ice cloud microphysical property profiles is developed by using the GSFC 9.6 GHz ER-2 Doppler Radar (EDOP) and the 94 GHz Cloud Radar System (CRS) measurements aboard the high-altitude ER-2 aircraft. In situ size distribution and total water content data from the CRYSTAL-FACE field campaign are used for the algorithm development. To reduce uncertainty in calculated radar reflectivity factors (Ze) at these wavelengths, coincident radar measurements and size distribution data are used to guide the selection of mass-length relationships and to deal with the density and non-spherical effects of ice crystals on the Ze calculations. The algorithm is able to retrieve microphysical property profiles of optically thick ice clouds, such as, deep convective and anvil clouds, which are very challenging for single frequency radar and lidar. Examples of retrieved microphysical properties for a deep convective clouds are presented, which show that EDOP and CRS measurements provide rich information to study cloud structure and evolution. Good agreement between IWPs derived from an independent submillimeter-wave radiometer, CoSSIR, and dual-wavelength radar measurements indicates accuracy of the IWC retrieved from the two-frequency radar algorithm.

  20. Measuring Geophysical Parameters of the Greenland Ice Sheet using Airborne Radar Altimetry

    NASA Technical Reports Server (NTRS)

    Ferraro, Ellen J.; Swift. Calvin T.

    1995-01-01

    This paper presents radar-altimeter scattering models for each of the diagenetic zones of the Greenland ice sheet. AAFE radar- altimeter waveforms obtained during the 1991 and 1993 NASA multi-sensor airborne altimetry experiments over Greenland reveal that the Ku-band return pulse changes significantly with the different diagenetic zones. These changes are due to varying amounts of surface and volume scattering in the return waveform. In the ablation and soaked zones, where surface scattering dominates the AAFE return, geophysical parameters such as rms surface height and rms surface slope are obtained by fitting the waveforms to a surface-scattering model. Waveforms from the percolation zone show that the sub-surface ice features have a much more significant effect on the return pulse than the surrounding snowpack. Model percolation waveforms, created using a combined surface- and volume-scattering model and an ice-feature distribution obtained during the 1993 field season, agree well with actual AAFE waveforms taken in the same time period. Using a combined surface- and volume-scattering model for the dry-snow-zone return waveforms, the rms surface height and slope and the attenuation coefficient of the snowpack are obtained. These scattering models not only allow geophysical parameters of the ice sheet to be measured but also help in the understanding of satellite radar-altimeter data.

  1. Penn State Radar Systems: Implementation and Observations

    NASA Astrophysics Data System (ADS)

    Urbina, J. V.; Seal, R.; Sorbello, R.; Kuyeng, K.; Dyrud, L. P.

    2014-12-01

    Software Defined Radio/Radar (SDR) platforms have become increasingly popular as researchers, hobbyists, and military seek more efficient and cost-effective means for radar construction and operation. SDR platforms, by definition, utilize a software-based interface for configuration in contrast to traditional, hard-wired platforms. In an effort to provide new and improved radar sensing capabilities, Penn State has been developing advanced instruments and technologies for future radars, with primary objectives of making such instruments more capable, portable, and more cost effective. This paper will describe the design and implementation of two low-cost radar systems and their deployment in ionospheric research at both low and mid-latitudes. One radar has been installed near Penn State campus, University Park, Pennsylvania (77.97°W, 40.70°N), to make continuous meteor observations and mid-latitude plasma irregularities. The second radar is being installed in Huancayo (12.05°S, -75.33°E), Peru, which is capable of detecting E and F region plasma irregularities as well as meteor reflections. In this paper, we examine and compare the diurnal and seasonal variability of specular, non- specular, and head-echoes collected with these two new radar systems and discuss sampling biases of each meteor observation technique. We report our current efforts to validate and calibrate these radar systems with other VHF radars such as Jicamarca and SOUSY. We also present the general characteristics of continuous measurements of E-region and F-region coherent echoes using these modern radar systems and compare them with coherent radar events observed at other geographic mid-latitude radar stations.

  2. TRMM Precipitation Radar Reflectivity Profiles Compared to High-Resolution Airborne and Ground-Based Radar Measurements

    NASA Technical Reports Server (NTRS)

    Heymsfield, G. M.; Geerts, B.; Tian, L.

    1999-01-01

    In this paper, TRMM (Tropical Rainfall Measuring Mission Satellite) Precipitation Radar (PR) products are evaluated by means of simultaneous comparisons with data from the high-altitude ER-2 Doppler Radar (EDOP), as well as ground-based radars. The comparison is aimed primarily at the vertical reflectivity structure, which is of key importance in TRMM rain type classification and latent heating estimation. The radars used in this study have considerably different viewing geometries and resolutions, demanding non-trivial mapping procedures in common earth-relative coordinates. Mapped vertical cross sections and mean profiles of reflectivity from the PR, EDOP, and ground-based radars are compared for six cases. These cases cover a stratiform frontal rainband, convective cells of various sizes and stages, and a hurricane. For precipitating systems that are large relative to the PR footprint size, PR reflectivity profiles compare very well to high-resolution measurements thresholded to the PR minimum reflectivity, and derived variables such as bright band height and rain types are accurate, even at high PR incidence angles. It was found that for, the PR reflectivity of convective cells small relative to the PR footprint is weaker than in reality. Some of these differences can be explained by non-uniform beam filling. For other cases where strong reflectivity gradients occur within a PR footprint, the reflectivity distribution is spread out due to filtering by the PR antenna illumination pattern. In these cases, rain type classification may err and be biased towards the stratiform type, and the average reflectivity tends to be underestimated. The limited sensitivity of the PR implies that the upper regions of precipitation systems remain undetected and that the PR storm top height estimate is unreliable, usually underestimating the actual storm top height. This applies to all cases but the discrepancy is larger for smaller cells where limited sensitivity is compounded

  3. Auxiliary DCP data acquisition system. [airborne system

    NASA Technical Reports Server (NTRS)

    Snyder, R. V.

    1975-01-01

    An airborne DCP Data Aquisition System has been designed to augment the ERTS satellite data recovery system. The DCP's are data collection platforms located at pertinent sites. With the appropriate sensors they are able to collect, digitally encode and transmit environmental parameters to the ERTS satellite. The satellite in turn relays these transmissions to a ground station for processing. The satellite is available for such relay duty a minimum of two times in a 24-hour period. The equipment is to obtain continuous DCP data during periods of unusual environmental activity--storms, floods, etc. Two circumstances contributed to the decision to design such a system; (1) Wallops Station utilizes surveillance aircraft in support of rocket launches and also in support of earth resources activities; (2) the area in which Wallops is located, the Delaware and Chesapeake Bay areas, are fertile areas for DCP usage. Therefore, by developing an airborne DCP receiving station and installing it on aircraft more continuous DCP data can be provided from sites in the surrounding areas at relatively low cost.

  4. Inner Core Structure of Hurricane Alicia from Airborne Doppler Radar Observations.

    NASA Astrophysics Data System (ADS)

    Marks, Frank D., Jr.; Houze, Robert A., Jr.

    1987-05-01

    Airborne Doppler radar measurements are used to determine the horizontal winds, vertical air motions, radar reflectivity and hydrometer fallspeeds over much of the inner-core region (within 40 km of the eye) of Hurricane Alicia (1983). The reconstructed flow field is more complete and detailed than any obtained previously. The data show both the primary (azimuthal) and secondary (radial-height) circulations. The primary circulation was characterized by an outward sloping maximum of tangential wind. The secondary circulation was characterized by a deep layer of radial inflow in the lower troposphere and a layer of intense outflow above 10 km altitude. The rising branch of the secondary circulation was located in the eyewall and sloped radially outward. Discrete convective-scale bubbles of more intense upward motion were superimposed on this mean rising current, and convective-scale downdrafts were located throughout and below the core of maximum precipitation in the eyewall.Precipitation particles in the eyewall rainshaft circulated 18-20 km downwind as they fell, consistent with the typical upwind slope with increasing altitude of eyewall precipitation cores Outside the eyewall, the precipitation was predominantly stratiform. A radar bright band was evident at the melting level. Above the melting level, ice particles were advected into the stratiform region from the upper levels of the eyewall and drifted downward through a mesoscale region of ascent. Hypothetical precipitation particle trajectories showed that as these particles fell slowly through the mesoscale updraft toward the melting level, they were carried azimuthally as many as 1 1/2 times around the storm. During this spiraling descent, the particles evidently grew vigorously. The amount of water condensed by the ambient mesoscale ascent exceeded that transported into the stratiform region by the eyewall outflow by a factor of 3. As the particles fell into the lower troposphere, they entered a mesoscale

  5. A multisensor system for airborne surveillance of oil pollution

    NASA Technical Reports Server (NTRS)

    Edgerton, A. T.; Ketchal, R.; Catoe, C.

    1973-01-01

    The U.S. Coast Guard is developing a prototype airborne oil surveillance system for use in its Marine Environmental Protection Program. The prototype system utilizes an X-band side-looking radar, a 37-GHz imaging microwave radiometer, a multichannel line scanner, and a multispectral low light level system. The system is geared to detecting and mapping oil spills and potential pollution violators anywhere within a 25 nmi range of the aircraft flight track under all but extreme weather conditions. The system provides for false target discrimination and maximum identification of spilled materials. The system also provides an automated detection alarm, as well as a color display to achieve maximum coupling between the sensor data and the equipment operator.

  6. Progress in Development of an Airborne Turbulence Detection System

    NASA Technical Reports Server (NTRS)

    Hamilton, David W.; Proctor, Fred H.

    2006-01-01

    Aircraft encounters with turbulence are the leading cause of in-flight injuries (Tyrvanas 2003) and have occasionally resulted in passenger and crew fatalities. Most of these injuries are caused by sudden and unexpected encounters with severe turbulence in and around convective activity (Kaplan et al 2005). To alleviate this problem, the Turbulence Prediction and Warning Systems (TPAWS) element of NASA s Aviation Safety program has investigated technologies to detect and warn of hazardous in-flight turbulence. This effort has required the numerical modeling of atmospheric convection: 1) for characterizing convectively induced turbulence (CIT) environments, 2) for defining turbulence hazard metrics, and 3) as a means of providing realistic three-dimensional data sets that can be used to test and evaluate turbulence detection sensors. The data sets are being made available to industry and the FAA for certification of future airborne turbulence-detection systems (ATDS) with warning capability. Early in the TPAWS project, a radar-based ATDS was installed and flight tested on NASA s research aircraft, a B-757. This ATDS utilized new algorithms and hazard metrics that were developed for use with existing airborne predictive windshear radars, thus avoiding the installation of new hardware. This system was designed to detect and warn of hazardous CIT even in regions with weak radar reflectivity (i.e. 5-15 dBz). Results from an initial flight test of the ATDS were discussed in Hamilton and Proctor (2002a; 2002b). In companion papers (Proctor et al 2002a; 2002b), a numerical simulation of the most significant encounter from that flight test was presented. Since the presentation of these papers a second flight test has been conducted providing additional cases for examination. In this paper, we will present results from NASA s flight test and a numerical model simulation of a turbulence environment encountered on 30 April 2002. Progress leading towards FAA certification of

  7. Recent ice sheet snow accumulation and firn storage of meltwater inferred by ground and airborne radars

    NASA Astrophysics Data System (ADS)

    Miege, Clement

    Recent surface mass balance changes in space and time over the polar ice sheets need to be better constrained in order to estimate the ice-sheet contribution to sea-level rise. The mass balance of any ice body is obtained by subtracting mass losses from mass gains. In response to climate changes of the recent decades, ice-sheet mass losses have increased, making ice-sheet mass balance negative and raising sea level. In this work, I better quantify the mass gained by snowfall across the polar ice sheets; I target specific regions over both Greenland and West Antarctica where snow accumulation changes are occurring due to rising air temperature. Southeast Greenland receives 30% of the total snow accumulation of the Greenland ice sheet. In this work, I combine internal layers observed in ice-penetrating radar data with firn cores to derive the last 30 years of accumulation and to measure the spatial pattern of accumulation toward the southeast coastline. Below 1800 m elevation, in the percolation zone, significant surface melt is observed in the summer, which challenges both firn-core dating and internal-layer tracing. While firn-core drilling at 1500 m elevation, liquid water was found at ˜20-m depth in a firn aquifer that persisted over the winter. The presence of this water filling deeper pore space in the firn was unexpected, and has a significant impact on the ice sheet thermal state and the estimate of mass balance made using satellite altimeters. Using a 400-MHz ice-penetrating radar, the extent of this widespread aquifer was mapped on the ground, and also more extensively from the air with a 750-MHz airborne radar as part of the NASA Operation IceBridge mission. Over three IceBridge flight campaigns (2011-2013), based on radar data, the firn aquifer is estimated to cover ˜30,000 km2 area within the wet-snow zone of the ice sheet. I use repeated flightlines to understand the temporal variability of the water trapped in the firn aquifer and to simulate its

  8. Operations Manager Tim Miller checks out software for the Airborne Synthetic Aperature Radar (AIRSAR

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Tim Miller checks out software for the Airborne Synthetic Aperture Radar (AIRSAR). He was the AIRSAR operations manager for NASA's Jet Propulsion Laboratory. The AIRSAR produces imaging data for a range of studies conducted by the DC-8. NASA is using a DC-8 aircraft as a flying science laboratory. The platform aircraft, based at NASA's Dryden Flight Research Center, Edwards, Calif., collects data for many experiments in support of scientific projects serving the world scientific community. Included in this community are NASA, federal, state, academic and foreign investigators. Data gathered by the DC-8 at flight altitude and by remote sensing have been used for scientific studies in archeology, ecology, geography, hydrology, meteorology, oceanography, volcanology, atmospheric chemistry, soil science and biology.

  9. Comparison of surface wind stress measurements - Airborne radar scatterometer versus sonic anemometer

    NASA Technical Reports Server (NTRS)

    Brucks, J. T.; Leming, T. D.; Jones, W. L.

    1980-01-01

    Sea surface wind stress measurements recorded by a sonic anemometer are correlated with airborne scatterometer measurements of ocean roughness (cross section of radar backscatter) to establish the accuracy of remotely sensed data and assist in the definition of geophysical algorithms for the scatterometer sensor aboard Seasat A. Results of this investigation are as follows: Comparison of scatterometer and sonic anemometer wind stress measurements are good for the majority of cases; however, a tendency exists for scatterometer wind stress to be somewhat high for higher wind conditions experienced in this experiment (6-9 m/s). The scatterometer wind speed algorithm tends to overcompute the higher wind speeds by approximately 0.5 m/s. This is a direct result of the scatterometer overestimate of wind stress from which wind speeds are derived. Algorithmic derivations of wind speed and direction are, in most comparisons, within accuracies defined by Seasat A scatterometer sensor specifications.

  10. The US Geological Survey's side-looking airborne radar acquisition program: Image data from the Rocky Mountains to the Pacific

    SciTech Connect

    Kovar, A.N.; Schoonmaker, J.W. Jr. )

    1993-04-01

    The US Geological Survey (USGS) has been systematically collecting side-looking airborne radar (SLAR) image data for the US since 1980. The image strip swaths, ranging in width from 20 to 46 km, are acquired commercially by X-band (3 cm) radar systems. Data are acquired with 60 percent side-lap for better mosaic preparation and stereoscopic capability. The image strips are assembled into 1[degree] x 2[degree] mosaic quadrangles that are based on the USGS 1:250,000-topographic map series for control, format, and nomenclature. These mosaics present the data in a broad synoptic view that facilitates geologic interpretation. SLAR image mosaics have been prepared for more than 35 percent of the US west of the Rocky Mountain front. In addition to quadrangle mosaics, regional composite mosaics have been prepared as value-added products. These include Pacific Northwest (14 quadrangles), southern California Coastal (from San Francisco to San Diego), Reno-Walker (includes parts of Yellowstone and Grand Teton National Parks), Uinta Basin (Salt Lake City, Price and Grand Junction), and Salton Sea Region (San Diego, Santa Ana, El Centro and Salton Sea). Most of the image data are available on computer compatible tapes and photographic products. To make the data more accessible and reasonably priced, the strip images are being processed into CD-ROM (compact disc, read-only memory). One demonstration CD-ROM includes the mosaics of Las Vegas, Mariposa, Ritzville, Walla Walla, and Pendleton quadrangles.

  11. Adaptive clutter rejection filters for airborne Doppler weather radar applied to the detection of low altitude windshear

    NASA Technical Reports Server (NTRS)

    Keel, Byron M.

    1989-01-01

    An optimum adaptive clutter rejection filter for use with airborne Doppler weather radar is presented. The radar system is being designed to operate at low-altitudes for the detection of windshear in an airport terminal area where ground clutter returns may mask the weather return. The coefficients of the adaptive clutter rejection filter are obtained using a complex form of a square root normalized recursive least squares lattice estimation algorithm which models the clutter return data as an autoregressive process. The normalized lattice structure implementation of the adaptive modeling process for determining the filter coefficients assures that the resulting coefficients will yield a stable filter and offers possible fixed point implementation. A 10th order FIR clutter rejection filter indexed by geographical location is designed through autoregressive modeling of simulated clutter data. Filtered data, containing simulated dry microburst and clutter return, are analyzed using pulse-pair estimation techniques. To measure the ability of the clutter rejection filters to remove the clutter, results are compared to pulse-pair estimates of windspeed within a simulated dry microburst without clutter. In the filter evaluation process, post-filtered pulse-pair width estimates and power levels are also used to measure the effectiveness of the filters. The results support the use of an adaptive clutter rejection filter for reducing the clutter induced bias in pulse-pair estimates of windspeed.

  12. Numerical simulation of imaging laser radar system

    NASA Astrophysics Data System (ADS)

    Han, Shaokun; Lu, Bo; Jiang, Ming; Liu, Xunliang

    2008-03-01

    Rational and effective design of imaging laser radar systems is the key of imaging laser radar system research. Design must fully consider the interrelationship between various parameters. According to the parameters, choose suitable laser, detector and other components. To use of mathematical modeling and computer simulation is an effective imaging laser radar system design methods. This paper based on the distance equation, using the detection statistical methods, from the laser radar range coverage, detection probability, false-alarm rate, SNR to build the laser radar system mathematical models. In the process of setting up the mathematical models to fully consider the laser, atmosphere, detector and other factors on the performance that is to make the models be able to respond accurately the real situation. Based on this using C# and Matlab designed a simulation software.

  13. BioSAR Airborne Biomass Sensing System

    SciTech Connect

    Graham, R.L.; Johnson, P.

    2007-05-24

    This CRADA was developed to enable ORNL to assist American Electronics, Inc. test a new technology--BioSAR. BioSAR is a an airborne, low frequency (80-120 MHz {approx} FM radio frequencies) synthetic aperture radar (SAR) technology which was designed and built for NASA by ZAI-Amelex under Patrick Johnson's direction. At these frequencies, leaves and small branches are nearly transparent and the majority of the energy reflected from the forest and returned to the radar is from the tree trunks. By measuring the magnitude of the back scatter, the volume of the tree trunk and therefore the biomass of the trunks can be inferred. The instrument was successfully tested on tropical rain forests in Panama. Patrick Johnson, with American Electronics, Inc received a Phase II SBIR grant from DOE Office of Climate Change to further test and refine the instrument. Mr Johnson sought ORNL expertise in measuring forest biomass in order for him to further validate his instrument. ORNL provided ground truth measurements of forest biomass at three locations--the Oak Ridge Reservation, Weyerhaeuser Co. commercial pine plantations in North Carolina, and American Energy and Power (AEP) Co. hardwood forests in southern Ohio, and facilitated flights over these forests. After Mr. Johnson processed the signal data from BioSAR instrument, the processed data were given to ORNL and we attempted to derive empirical relationships between the radar signals and the ground truth forest biomass measurements using standard statistical techniques. We were unsuccessful in deriving such relationships. Shortly before the CRADA ended, Mr Johnson discovered that FM signal from local radio station broadcasts had interfered with the back scatter measurements such that the bulk of the signal received by the BioSAR instrument was not backscatter from the radar but rather was local radio station signals.

  14. Airborne space laser communication system and experiments

    NASA Astrophysics Data System (ADS)

    Li, Xiao-Ming; Zhang, Li-zhong; Meng, Li-Xin

    2015-11-01

    Airborne space laser communication is characterized by its high speed, anti-electromagnetic interference, security, easy to assign. It has broad application in the areas of integrated space-ground communication networking, military communication, anti-electromagnetic communication. This paper introduce the component and APT system of the airborne laser communication system design by Changchun university of science and technology base on characteristic of airborne laser communication and Y12 plan, especially introduce the high communication speed and long distance communication experiment of the system that among two Y12 plans. In the experiment got the aim that the max communication distance 144Km, error 10-6 2.5Gbps - 10-7 1.5Gbps capture probability 97%, average capture time 20s. The experiment proving the adaptability of the APT and the high speed long distance communication.

  15. Multisensor airborne imagery collection and processing onboard small unmanned systems

    NASA Astrophysics Data System (ADS)

    Linne von Berg, Dale; Anderson, Scott A.; Bird, Alan; Holt, Niel; Kruer, Melvin; Walls, Thomas J.; Wilson, Michael L.

    2010-04-01

    FEATHAR (Fusion, Exploitation, Algorithms, and Targeting for High-Altitude Reconnaissance) is an ONR funded effort to develop and test new tactical sensor systems specifically designed for small manned and unmanned platforms (payload weight < 50 lbs). This program is being directed and executed by the Naval Research Laboratory (NRL) in conjunction with the Space Dynamics Laboratory (SDL). FEATHAR has developed and integrated EyePod, a combined long-wave infrared (LWIR) and visible to near infrared (VNIR) optical survey & inspection system, with NuSAR, a combined dual band synthetic aperture radar (SAR) system. These sensors are being tested in conjunction with other ground and airborne sensor systems to demonstrate intelligent real-time cross-sensor cueing and in-air data fusion. Results from test flights of the EyePod and NuSAR sensors will be presented.

  16. Kharkiv Meteor Radar System (the XX Age)

    NASA Astrophysics Data System (ADS)

    Kolomiyets, S. V.

    2012-09-01

    Kharkiv meteor radar research are of historic value (Kolomiyets and Sidorov 2007). Kharkiv radar observations of meteors proved internationally as the best in the world, it was noted at the IAU General Assembly in 1958. In the 1970s Kharkiv meteor automated radar system (MARS) was recommended at the international level as a successful prototype for wide distribution. Until now, this radar system is one of the most sensitive instruments of meteor radars in the world for astronomical observations. In 2004 Kharkiv meteor radar system is included in the list of objects which compose the national property of Ukraine. Kharkiv meteor radar system has acquired the status of the important historical astronomical instrument in world history. Meteor Centre for researching meteors in Kharkiv is a analogue of the observatory and performs the same functions of a generator and a battery of special knowledge and skills (the world-famous studio). Kharkiv and the location of the instrument were brand points on the globe, as the place where the world-class meteor radar studies were carried out. They are inscribed in the history of meteor astronomy, in large letters and should be immortalized on a world-wide level.

  17. Reach scale floodplain inundation dynamics observed using airborne synthetic aperture radar imagery: Data analysis and modelling

    NASA Astrophysics Data System (ADS)

    Bates, Paul D.; Wilson, Matthew D.; Horritt, Matthew S.; Mason, David C.; Holden, Nick; Currie, Anthony

    2006-08-01

    SummaryIn this paper, we use an airborne synthetic aperture radar to map river flood inundation synoptically at fine spatial resolution (1.2 m) along a ˜16 km reach of the River Severn, west-central England. Images were obtained at four times through a large flood event between 8th and 17th November 2000 and processed using a statistical active contour algorithm to yield the flood shoreline at each time. Intersection of these data with a high vertical accuracy survey of floodplain topography obtained from airborne laser altimetry permitted the calculation of dynamic changes in inundated area, total reach storage and rates of reach dewatering. In addition, comparison of the data to gauged flow rates, the measured floodplain topography and map data giving the location of embankments and drainage channels on the floodplain yields new insights into the factors controlling the development of inundation patterns at a variety of scales. Finally, the data were used to assess the performance of a simple two-dimensional flood inundation model, LISFLOOD-FP, and allows us, for the first time, to validate the dynamic performance of the model. This process is shown to give new information into structural weaknesses of the model and suggests possible future developments, including the incorporation of a better description of floodplain hydrological processes in the hydraulic model to represent more accurately the dewatering of the floodplain.

  18. CBSIT 2009: Airborne Validation of Envisat Radar Altimetry and In Situ Ice Camp Measurements Over Arctic Sea Ice

    NASA Technical Reports Server (NTRS)

    Connor, Laurence; Farrell, Sinead; McAdoo, David; Krabill, William; Laxon, Seymour; Richter-Menge, Jacqueline; Markus, Thorsten

    2010-01-01

    The past few years have seen the emergence of satellite altimetry as valuable tool for taking quantitative sea ice monitoring beyond the traditional surface extent measurements and into estimates of sea ice thickness and volume, parameters that arc fundamental to improved understanding of polar dynamics and climate modeling. Several studies have now demonstrated the use of both microwave (ERS, Envisat/RA-2) and laser (ICESat/GLAS) satellite altimeters for determining sea ice thickness. The complexity of polar environments, however, continues to make sea ice thickness determination a complicated remote sensing task and validation studies remain essential for successful monitoring of sea ice hy satellites. One such validation effort, the Arctic Aircraft Altimeter (AAA) campaign of2006. included underflights of Envisat and ICESat north of the Canadian Archipelago using NASA's P-3 aircraft. This campaign compared Envisat and ICESat sea ice elevation measurements with high-resolution airborne elevation measurements, revealing the impact of refrozen leads on radar altimetry and ice drift on laser altimetry. Continuing this research and validation effort, the Canada Basin Sea Ice Thickness (CBSIT) experiment was completed in April 2009. CBSIT was conducted by NOAA. and NASA as part of NASA's Operation Ice Bridge, a gap-filling mission intended to supplement sea and land ice monitoring until the launch of NASA's ICESat-2 mission. CBIST was flown on the NASA P-3, which was equipped with a scanning laser altimeter, a Ku-band snow radar, and un updated nadir looking photo-imaging system. The CB5IT campaign consisted of two flights: an under flight of Envisat along a 1000 km track similar to that flown in 2006, and a flight through the Nares Strait up to the Lincoln Sea that included an overflight of the Danish GreenArc Ice Camp off the coast of northern Greenland. We present an examination of data collected during this campaign, comparing airborne laser altimeter measurements

  19. Simulation system of airborne FLIR searcher

    NASA Astrophysics Data System (ADS)

    Sun, Kefeng; Li, Yu; Gao, Jiaobo; Wang, Jun; Wang, Jilong; Xie, Junhu; Ding, Na; Sun, Dandan

    2014-11-01

    Airborne Forward looking infra-red (FLIR) searcher simulation system can provide multi-mode simulated test environment that almost actual field environment, and can simulate integrated performance and external interface of airborne FLIR simulation system. Furthermore, the airborne FLIR searcher simulation system can support the algorithm optimization of image processing, and support the test and evaluation of electro-optical system, and also support the line test of software and evaluate the performance of the avionics system. The detailed design structure and information cross-linking relationship of each component are given in this paper. The simulation system is composed of the simulation center, the FLIR actuator, the FLIR emulator, and the display control terminal. The simulation center can generate the simulated target and aircraft flying data in the operation state of the airborne FLIR Searcher. The FLIR actuator can provide simulation scene. It can generate the infrared target and landform based scanning scene, response to the commands from simulation center and the FLIR actuator and operation control unit. The infrared image generated by the FLIR actuator can be processed by the FLIR emulator using PowerPC hardware framework and processing software based on VxWorks system. It can detect multi-target and output the DVI video and the multi-target detection information which corresponds to the working state of the FLIR searcher. Display control terminal can display the multi-target detection information in two-dimension situation format, and realize human-computer interaction function.

  20. Analysis of airborne Doppler lidar, Doppler radar and tall tower measurements of atmospheric flows in quiescent and stormy weather

    NASA Technical Reports Server (NTRS)

    Bluestein, H. B.; Doviak, R. J.; Eilts, M. D.; Mccaul, E. W.; Rabin, R.; Sundara-Rajan, A.; Zrnic, D. S.

    1986-01-01

    The first experiment to combine airborne Doppler Lidar and ground-based dual Doppler Radar measurements of wind to detail the lower tropospheric flows in quiescent and stormy weather was conducted in central Oklahoma during four days in June-July 1981. Data from these unique remote sensing instruments, coupled with data from conventional in-situ facilities, i.e., 500-m meteorological tower, rawinsonde, and surface based sensors, were analyzed to enhance understanding of wind, waves and turbulence. The purposes of the study were to: (1) compare winds mapped by ground-based dual Doppler radars, airborne Doppler lidar, and anemometers on a tower; (2) compare measured atmospheric boundary layer flow with flows predicted by theoretical models; (3) investigate the kinematic structure of air mass boundaries that precede the development of severe storms; and (4) study the kinematic structure of thunderstorm phenomena (downdrafts, gust fronts, etc.) that produce wind shear and turbulence hazardous to aircraft operations. The report consists of three parts: Part 1, Intercomparison of Wind Data from Airborne Lidar, Ground-Based Radars and Instrumented 444 m Tower; Part 2, The Structure of the Convective Atmospheric Boundary Layer as Revealed by Lidar and Doppler Radars; and Part 3, Doppler Lidar Observations in Thunderstorm Environments.

  1. Airborne electronics for automated flight systems

    NASA Technical Reports Server (NTRS)

    Graves, G. B., Jr.

    1975-01-01

    The increasing importance of airborne electronics for use in automated flight systems is briefly reviewed with attention to both basic aircraft control functions and flight management systems for operational use. The requirements for high levels of systems reliability are recognized. Design techniques are discussed and the areas of control systems, computing and communications are considered in terms of key technical problems and trends for their solution.

  2. Intercomparison of single-frequency methods for retrieving a vertical rain profile from airborne or spaceborne radar data

    NASA Technical Reports Server (NTRS)

    Iguchi, Toshio; Meneghini, Robert

    1994-01-01

    This paper briefly reviews several single-frequency rain profiling methods for an airborne or spaceborne radar. The authors describe the different methods from a unified point of view starting from the basic differential equation. This facilitates the comparisons between the methods and also provides a better understanding of the physical and mathematical basis of the methods. The application of several methods to airborne radar data taken during the Convective and Precipitation/Electrification Experiment is shown. Finally, the authors consider a hybrid method that provides a smooth transition between the Hitschfeld-Bordan method, which performs well at low attenuations, and the surface reference method, for which the relative error decreases with increasing path attenuation.

  3. Airborne Systems Technology Application to the Windshear Threat

    NASA Technical Reports Server (NTRS)

    Arbuckle, P. Douglas; Lewis, Michael S.; Hinton, David A.

    1996-01-01

    The general approach and products of the NASA/FAA Airborne Windshear Program conducted by NASA Langley Research Center are summarized, with references provided for the major technical contributions. During this period, NASA conducted 2 years of flight testing to characterize forward-looking sensor performance. The NASA/FAA Airborne Windshear Program was divided into three main elements: Hazard Characterization, Sensor Technology, and Flight Management Systems. Simulation models developed under the Hazard Characterization element are correlated with flight test data. Flight test results comparing the performance and characteristics of the various Sensor Technologies (microwave radar, lidar, and infrared) are presented. Most of the activities in the Flight Management Systems element were conducted in simulation. Simulation results from a study evaluating windshear crew procedures and displays for forward-looking sensor-equipped airplanes are discussed. NASA Langley researchers participated heavily in the FAA process of generating certification guidelines for predictive windshear detection systems. NASA participants felt that more valuable technology products were generated by the program because of this interaction. NASA involvement in the process and the resulting impact on products and technology transfer are discussed in this paper.

  4. A data assimilation experiment of RASTA airborne cloud radar data during HyMeX IOP16

    NASA Astrophysics Data System (ADS)

    Saussereau, Gaël; Caumont, Olivier; Delanoë, Julien

    2015-04-01

    The main goal of HyMeX first special observing period (SOP1), which took place from 5 September to 5 November 2012, was to document the heavy precipitation events and flash floods that regularly affect the north-western Mediterranean coastal areas. In the two-month campaign, around twenty rainfall events were documented in France, Italy, and Spain. Among the instrumental platforms that were deployed during SOP1, the Falcon 20 of the Safire unit (http://www.safire.fr/) made numerous flights in storm systems so as to document their thermodynamic, microphysical, and dynamical properties. In particular, the RASTA cloud radar (http://rali.projet.latmos.ipsl.fr/) was aboard this aircraft. This radar measures vertical profiles of reflectivity and Doppler velocity above and below the aircraft. This unique instrument thus allows us to document the microphysical properties and the speed of wind and hydrometeors in the clouds, quasi-continuously in time and at a 60-m vertical resolution. For this field campaign, a special version of the numerical weather prediction (NWP) Arome system was developed to cover the whole north-western Mediterranean basin. This version, called Arome-WMed, ran in real time during the SOP in order to, notably, schedule the airborne operations, especially in storm systems. Like the operational version, Arome-WMed delivers forecasts at a horizontal resolution of 2.5 km with a one-moment microphysical scheme that predicts the evolution of six water species: water vapour, cloud liquid water, rainwater, pristine ice, snow, and graupel. Its three-dimensional variational (3DVar) data assimilation (DA) system ingests every three hours (at 00 UTC, 03 UTC, etc.) numerous observations (radiosoundings, ground automatic weather stations, radar, satellite, GPS, etc.). In order to provide improved initial conditions to Arome-WMed, especially for heavy precipitation events, RASTA data were assimilated in Arome-WMed 3DVar DA system for IOP16 (26 October 2012), to

  5. Improved Airborne System for Sensing Wildfires

    NASA Technical Reports Server (NTRS)

    McKeown, Donald; Richardson, Michael

    2008-01-01

    The Wildfire Airborne Sensing Program (WASP) is engaged in a continuing effort to develop an improved airborne instrumentation system for sensing wildfires. The system could also be used for other aerial-imaging applications, including mapping and military surveillance. Unlike prior airborne fire-detection instrumentation systems, the WASP system would not be based on custom-made multispectral line scanners and associated custom- made complex optomechanical servomechanisms, sensors, readout circuitry, and packaging. Instead, the WASP system would be based on commercial off-the-shelf (COTS) equipment that would include (1) three or four electronic cameras (one for each of three or four wavelength bands) instead of a multispectral line scanner; (2) all associated drive and readout electronics; (3) a camera-pointing gimbal; (4) an inertial measurement unit (IMU) and a Global Positioning System (GPS) receiver for measuring the position, velocity, and orientation of the aircraft; and (5) a data-acquisition subsystem. It would be necessary to custom-develop an integrated sensor optical-bench assembly, a sensor-management subsystem, and software. The use of mostly COTS equipment is intended to reduce development time and cost, relative to those of prior systems.

  6. Remote sensing of land scenarios with an airborne 94-GHz synthetic aperture radar

    NASA Astrophysics Data System (ADS)

    Essen, Helmut; Makaruschka, R.; Baars, E. Peter

    1996-06-01

    The scattering process of electromagnetic waves is dominated by the match between wavelength and the geometric dimensions of surface structures. With respect to the microwave radar bands millimeter-waves are better matched to small surface features of terrain. Therefore this frequency band is able to gain additional information on the terrain of interest. For high resolution imaging SAR is the favorite solution also for millimeter-wave frequencies. Compared to more classical radar bands millimeter-waves offer advantages in the SAR processing, because due to the higher primary resolution at a given antenna aperture sources of image distortions such as range migration or depth of focus can be neglected at these frequencies. Moreover the inherently short aperture time for a given resolution improves the relation to the time constant of flight instabilities and makes motion compensation a simple process. A coherent, polarimetric, high range resolution radar, operating at a nominal frequency of 94 GHz, has been installed onboard an aircraft to allow remote sensing measurements in a side looking synthetic aperture approach. The radar-raw-data were registered together with time code and inertial data of the aircraft and later on evaluated by an off-line SAR-processor. The resulting images then had to undergo an automatic recognition process to extract certain complex targets using a knowledge based production system. The paper describes the measurement system and discusses the evaluation procedures with emphasis on the applied SAR algorithm. Examples of radar images at 94 GHz are shown and samples of pattern recognition derived from the SAR images are shown.

  7. Hurricane Georges' Landfall in the Dominican Republic: Detailed Airborne Doppler Radar Imagery

    NASA Technical Reports Server (NTRS)

    Geerts, B.; Heymsfield, G. M.; Tian, L.; Halverson, J. B.; Guillory, A.; Mejia, M. I.

    1999-01-01

    Current understanding of landfalling tropical cyclones is limited, especially with regard to convective scale processes. On 22 September 1998 Hurricane Georges made landfall on the island of Hispaniola, leaving behind a trail of death and devastation, largely the result of excessive rainfall, not sea level surge or wind. Detailed airborne measurements were taken as part of the Third Convection and Moisture Experiment (CAMEX-3). Of Particular interest are the ER-2 nadir X-band Doppler radar (EDOP) data, which provide a first-time high-resolution view of the precipitation and airflow changes as a hurricane interacts with mountainous terrain. The circulation of hurricane Georges underwent an obvious transition during landfall, evident in the rapid increase in minimum sea-level pressure, the subsidence of the eyewall anvil, and a decrease in average ice concentrations in the eyewall. The eye, as seen in satellite imagery, disappeared, but contrary to current understanding, this was not due to eyewall contraction but rather to convective eruption within the eye. The main convective event within the eye, with upper-level updraft magnitudes near 20 m/s and 89 GHz brightness temperatures below 100 K, occurred when the eye moved over the Cordillera Central, the island's main mountain chain. The location, intensity and evolution of this convection indicate that it was coupled to the surface orography. It is likely that surface rain rates increased during landfall, because of effective droplet collection, both in the convection and in the more widespread stratiform rainfall areas over the island. Evidence for this is the increase in radar reflectivity below the bright band of 1-2 dB/km down to ground-level. Such increase was absent offshore. Such low-level rain enhancement, which cannot be detected in satellite images of upwelling infrared or microwave radiation, must be due to the ascent of boundary-layer air over the topography.

  8. Radar Studies in the Solar System

    NASA Technical Reports Server (NTRS)

    Shapiro, Irwin I.

    1996-01-01

    We aid in a study of the solar system by means of ground-based radar. We have concentrated on (1) developing the ephemerides needed to acquire radar data at Arecibo Observatory and (2) analyzing the resultant data to: test fundamental laws of gravitation; determine the size, shape, topography, and spin vectors of the targets; and study the surface properties of these objects, through their scattering law and polarization characteristics.

  9. CALIOPE airborne CO{sub 2} DIAL (CACDI) system design

    SciTech Connect

    Mietz, D.; Archuleta, B.; Archuleta, J.

    1997-09-01

    Los Alamos National Laboratory is currently developing an airborne CO{sub 2} Differential Absorption Lidar (DIAL) system based on second generation technology demonstrated last summer at NTS. The CALIOPE Airborne CO{sub 2} DIAL (CACDI) system requirements have been compiled based on the mission objectives and SONDIAL model trade studies. Subsystem designs have been developed based on flow down from these system requirements, as well as experience gained from second generation ground tests and N-ABLE (Non-proliferation AirBorne Lidar Experiments) airborne experiments. This paper presents the CACDI mission objectives, system requirements, the current subsystem design, and provides an overview of the airborne experimental plan.

  10. Designing clutter rejection filters with complex coefficients for airborne pulsed Doppler weather radar

    NASA Technical Reports Server (NTRS)

    Jamora, Dennis A.

    1993-01-01

    Ground clutter interference is a major problem for airborne pulse Doppler radar operating at low altitudes in a look-down mode. With Doppler zero set at the aircraft ground speed, ground clutter rejection filtering is typically accomplished using a high-pass filter with real valued coefficients and a stopband notch centered at zero Doppler. Clutter spectra from the NASA Wind Shear Flight Experiments of l991-1992 show that the dominant clutter mode can be located away from zero Doppler, particularly at short ranges dominated by sidelobe returns. Use of digital notch filters with complex valued coefficients so that the stopband notch can be located at any Doppler frequency is investigated. Several clutter mode tracking algorithms are considered to estimate the Doppler frequency location of the dominant clutter mode. From the examination of night data, when a dominant clutter mode away from zero Doppler is present, complex filtering is able to significantly increase clutter rejection over use of a notch filter centered at zero Doppler.

  11. Air-Sea Spray Airborne Radar Profiler Characterizes Energy Fluxes in Hurricanes

    NASA Technical Reports Server (NTRS)

    Durden, Stephen L.; Esteban-Fermandez, D.

    2010-01-01

    A report discusses ASAP (Air-sea Spray Airborne Profiler), a dual-wavelength radar profiler that provides measurement information about the droplet size distribution (DSD) of sea-spray, which can be used to estimate heat and moisture fluxes for hurricane research. Researchers have recently determined that sea spray can have a large effect on the magnitude and distribution of the air-sea energy flux at hurricane -force wind speeds. To obtain information about the DSD, two parameters of the DSD are required; for example, overall DSD amplitude and DSD mean diameter. This requires two measurements. Two frequencies are used, with a large enough separation that the differential frequency provides size information. One frequency is 94 GHz; the other is 220 GHz. These correspond to the Rayleigh and Mie regions. Above a surface wind speed of 10 m/ s, production of sea spray grows exponentially. Both the number of large droplets and the altitude they reach are a function of the surface wind speed.

  12. Performance metrics for an airborne imaging system

    NASA Astrophysics Data System (ADS)

    Dayton, David C.; Gonglewski, John D.

    2004-11-01

    A series of airborne imaging experiments have been conducted on the island of Maui and at North Oscura Peak in New Mexico. Two platform altitudes were considered 3000 meters and 600 meters, both with a slant range to the target up to 10000 meters. The airborne imaging platform was a Twin Otter aircraft, which circled ground target sites. The second was a fixed platform on a mountain peak overlooking a valley 600 meters below. The experiments were performed during the day using solar illuminated target buildings. Imaging system performance predictions were calculated using standard atmospheric turbulence models, and aircraft boundary layer models. Several different measurement approaches were then used to estimate the actual system performance, and make comparisons with the calculations.

  13. 78 FR 19063 - Airworthiness Approval for Aircraft Forward-Looking Windshear and Turbulence Radar Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-28

    ..., Airborne Weather Radar Equipment. The objective is to leverage the installation specific guidance from the... previously addressed as additional functionality added to TSO-C63c, Airborne Weather and Ground...

  14. Airborne HCl - CO sensing system

    NASA Technical Reports Server (NTRS)

    Bartle, E. R.; Hall, G.

    1977-01-01

    A system for measuring air pollutants in-situ using an aircraft was designed, fabricated, and tested. The system is based upon a technique called Gas Filter Correlation (GFC) which provides for high sensitivity and specificity in the presence of interfering species. This particular system was designed for measuring hydrochloric acid and carbon monoxide gases emitted from rocket exhaust effluents.

  15. Development of a Cost-Effective Airborne Remote Sensing System for Coastal Monitoring.

    PubMed

    Kim, Duk-jin; Jung, Jungkyo; Kang, Ki-mook; Kim, Seung Hee; Xu, Zhen; Hensley, Scott; Swan, Aaron; Duersch, Michael

    2015-09-30

    Coastal lands and nearshore marine areas are productive and rapidly changing places. However, these areas face many environmental challenges related to climate change and human-induced impacts. Space-borne remote sensing systems may be restricted in monitoring these areas because of their spatial and temporal resolutions. In situ measurements are also constrained from accessing the area and obtaining wide-coverage data. In these respects, airborne remote sensing sensors could be the most appropriate tools for monitoring these coastal areas. In this study, a cost-effective airborne remote sensing system with synthetic aperture radar and thermal infrared sensors was implemented to survey coastal areas. Calibration techniques and geophysical model algorithms were developed for the airborne system to observe the topography of intertidal flats, coastal sea surface current, sea surface temperature, and submarine groundwater discharge.

  16. Development of a Cost-Effective Airborne Remote Sensing System for Coastal Monitoring

    PubMed Central

    Kim, Duk-jin; Jung, Jungkyo; Kang, Ki-mook; Kim, Seung Hee; Xu, Zhen; Hensley, Scott; Swan, Aaron; Duersch, Michael

    2015-01-01

    Coastal lands and nearshore marine areas are productive and rapidly changing places. However, these areas face many environmental challenges related to climate change and human-induced impacts. Space-borne remote sensing systems may be restricted in monitoring these areas because of their spatial and temporal resolutions. In situ measurements are also constrained from accessing the area and obtaining wide-coverage data. In these respects, airborne remote sensing sensors could be the most appropriate tools for monitoring these coastal areas. In this study, a cost-effective airborne remote sensing system with synthetic aperture radar and thermal infrared sensors was implemented to survey coastal areas. Calibration techniques and geophysical model algorithms were developed for the airborne system to observe the topography of intertidal flats, coastal sea surface current, sea surface temperature, and submarine groundwater discharge. PMID:26437413

  17. Radar Studies in the Solar System

    NASA Technical Reports Server (NTRS)

    Shaprio, Irwin I.

    1998-01-01

    We aid in study of the solar system by means of ground-based radar. We have concentrated on: (1) developing the ephemerides needed to acquire radar data at Arecibo Observatory and (2) analyzing the resultant data to: test fundamental laws of gravitation; determine the size , shape, topography, and spin vectors of the targets; and study the surface properties of these objects, through their scattering law and polarization characteristics. We are engaged in radar observations of asteroids and comets, both as systematically planned targets and as "targets of opportunity." In the course of the program, we have prepared ephemerides for about 80 asteroids and three comets, and the radar observations have been made or attempted at the Arecibo Observatory, in most cases successfully, and in some cases on more than one apparition. The results of these observations have included echo spectra for the targets and, in some cases, delay - Doppler images and measurements of the total round-trip delay to the targets. Perhaps the most dramatic of these results are the images obtained for asteroids (4179) Toutatis and 1989PB (Castalia), which were revealed to be double-lobed objects by the radar images. Besides these direct results, the radar observations have furnished information on the sizes and shapes of the targets through analysis of the Doppler width of the echoes as a function of time, and on the surface properties (such as composition, bulk density, and roughness) through analysis of the reflectivity and of the polarization state of the echoes. We have also refined the orbits of the observed asteroids as a result of the Doppler (and in some cases delay) measurements from the radar observations. Although the orbits of main-belt asteroids accessible to ground-based radar are quite well known from the available optical data, some near-Earth objects have been seen by radar very soon after their optical discovery (for example, 199OMF, just eight days after discovery). In such

  18. Urban Flood Warning Systems using Radar Technologies

    NASA Astrophysics Data System (ADS)

    Fang, N.; Bedient, P. B.

    2013-12-01

    There have been an increasing number of urban areas that rely on weather radars to provide accurate precipitation information for flood warning purposes. As non-structural tools, radar-based flood warning systems can provide accurate and timely warnings to the public and private entities in urban areas that are prone to flash floods. The wider spatial and temporal coverage from radar increases flood warning lead-time when compared to rain and stream gages alone. The Third Generation Rice and Texas Medical Center (TMC) Flood Alert System (FAS3) has been delivering warning information with 2 to 3 hours of lead time and a R2 value of 93% to facility personnel in a readily understood format for more than 50 events in the past 15 years. The current FAS utilizes NEXRAD Level II radar rainfall data coupled with a real-time hydrologic model (RTHEC-1) to deliver warning information. The system has a user-friendly dashboard to provide rainfall maps, Google Maps based inundation maps, hydrologic predictions, and real-time monitoring at the bayou. This paper will evaluate its reliable performance during the recent events occurring in 2012 and 2013 and the development of a similar radar-based flood warning system for the City of Sugar Land, Texas. Having a significant role in the communication of flood information, FAS marks an important step towards the establishment of an operational and reliable flood warning system for flood-prone urban areas.

  19. Airborne Atmospheric Aerosol Measurement System

    NASA Astrophysics Data System (ADS)

    Ahn, K.; Park, Y.; Eun, H.; Lee, H.

    2015-12-01

    It is important to understand the atmospheric aerosols compositions and size distributions since they greatly affect the environment and human health. Particles in the convection layer have been a great concern in global climate changes. To understand these characteristics satellite, aircraft, and radio sonde measurement methods have usually been used. An aircraft aerosol sampling using a filter and/or impactor was the method commonly used (Jay, 2003). However, the flight speed particle sampling had some technical limitations (Hermann, 2001). Moreover, the flight legal limit, altitude, prohibited airspace, flight time, and cost was another demerit. To overcome some of these restrictions, Tethered Balloon Package System (T.B.P.S.) and Recoverable Sonde System(R.S.S.) were developed with a very light optical particle counter (OPC), impactor, and condensation particle counter (CPC). Not only does it collect and measure atmospheric aerosols depending on altitudes, but it also monitors the atmospheric conditions, temperature, humidity, wind velocity, pressure, GPS data, during the measurement (Eun, 2013). In this research, atmospheric aerosol measurement using T.B.P.S. in Ansan area is performed and the measurement results will be presented. The system can also be mounted to an unmanned aerial vehicle (UAV) and create an aerial particle concentration map. Finally, we will present measurement data using Tethered Balloon Package System (T.B.P.S.) and R.S.S (Recoverable Sonde System).

  20. Aircraft radar antennas

    NASA Astrophysics Data System (ADS)

    Schrank, Helmut E.

    1987-04-01

    Many changes have taken place in airborne radar antennas since their beginnings over forty years ago. A brief historical review of the advances in technology is presented, from mechanically scanned reflectors to modern multiple function phased arrays. However, emphasis is not on history but on the state-of-the-art technology and trends for future airborne radar systems. The status of rotating surveillance antennas is illustrated by the AN/APY-1 Airborne Warning and Control System (AWACS) slotted waveguide array, which achieved a significant breakthrough in sidelobe suppression. Gimballed flat plate arrays in nose radomes are typified by the AN/APG-66 (F-16) antenna. Multifunction phased arrays are presented by the Electronically Agile Radar (EAR) antenna, which has achieved significant advances in performance versatility and reliability. Trends toward active aperture, adaptive, and digital beamforming arrays are briefly discussed. Antennas for future aircraft radar systems must provide multiple functions in less aperture space, and must perform more reliably.

  1. Preliminary results of the LLNL airborne experimental test-bed SAR system

    SciTech Connect

    Miller, M.G.; Mullenhoff, C.J.; Kiefer, R.D.; Brase, J.M.; Wieting, M.G.; Berry, G.L.; Jones, H.E.

    1996-01-16

    The Imaging and Detection Program (IDP) within Laser Programs at Lawrence Livermore National Laboratory (LLNL) in cooperation with the Hughes Aircraft Company has developed a versatile, high performance, airborne experimental test-bed (AETB) capability. The test-bed has been developed for a wide range of research and development experimental applications including radar and radiometry plus, with additional aircraft modifications, optical systems. The airborne test-bed capability has been developed within a Douglas EA-3B Skywarrior jet aircraft provided and flown by Hughes Aircraft Company. The current test-bed payload consists of an X-band radar system, a high-speed data acquisition, and a real-time processing capability. The medium power radar system is configured to operate in a high resolution, synthetic aperture radar (SAR) mode and is highly configurable in terms of waveforrns, PRF, bandwidth, etc. Antennas are mounted on a 2-axis gimbal in the belly radome of the aircraft which provides pointing and stabilization. Aircraft position and antenna attitude are derived from a dedicated navigational system and provided to the real-time SAR image processor for instant image reconstruction and analysis. This paper presents a further description of the test-bed and payload subsystems plus preliminary results of SAR imagery.

  2. A prototype radar fracture mapping system

    SciTech Connect

    Chang, Hsi-Tien

    1987-01-01

    The design and fabrication of a prototype radar system for fracture detection have been completed. This system uses directional antennas for both the transmitter and the receiver in a single tool which provides both the distance and the direction of a fracture in a downhole application. Electronic circuits in the system generate 50 kW peak power impulse with -100 dbm minimum detectable sensitivity. Unique downhole sampling and uphole data reconstruction techniques are used to obtain high frequency data using standard logging cable. In a recent test conducted in a lake, radar returns from a target were clearly observed. Problems encountered in the prototype and the future test plans are discussed.

  3. The design and development of signal-processing algorithms for an airborne x-band Doppler weather radar

    NASA Technical Reports Server (NTRS)

    Nicholson, Shaun R.

    1994-01-01

    Improved measurements of precipitation will aid our understanding of the role of latent heating on global circulations. Spaceborne meteorological sensors such as the planned precipitation radar and microwave radiometers on the Tropical Rainfall Measurement Mission (TRMM) provide for the first time a comprehensive means of making these global measurements. Pre-TRMM activities include development of precipitation algorithms using existing satellite data, computer simulations, and measurements from limited aircraft campaigns. Since the TRMM radar will be the first spaceborne precipitation radar, there is limited experience with such measurements, and only recently have airborne radars become available that can attempt to address the issue of the limitations of a spaceborne radar. There are many questions regarding how much attenuation occurs in various cloud types and the effect of cloud vertical motions on the estimation of precipitation rates. The EDOP program being developed by NASA GSFC will provide data useful for testing both rain-retrieval algorithms and the importance of vertical motions on the rain measurements. The purpose of this report is to describe the design and development of real-time embedded parallel algorithms used by EDOP to extract reflectivity and Doppler products (velocity, spectrum width, and signal-to-noise ratio) as the first step in the aforementioned goals.

  4. Cassini radar : system concept and simulation results

    NASA Astrophysics Data System (ADS)

    Melacci, P. T.; Orosei, R.; Picardi, G.; Seu, R.

    1998-10-01

    The Cassini mission is an international venture, involving NASA, the European Space Agency (ESA) and the Italian Space Agency (ASI), for the investigation of the Saturn system and, in particular, Titan. The Cassini radar will be able to see through Titan's thick, optically opaque atmosphere, allowing us to better understand the composition and the morphology of its surface, but the interpretation of the results, due to the complex interplay of many different factors determining the radar echo, will not be possible without an extensive modellization of the radar system functioning and of the surface reflectivity. In this paper, a simulator of the multimode Cassini radar will be described, after a brief review of our current knowledge of Titan and a discussion of the contribution of the Cassini radar in answering to currently open questions. Finally, the results of the simulator will be discussed. The simulator has been implemented on a RISC 6000 computer by considering only the active modes of operation, that is altimeter and synthetic aperture radar. In the instrument simulation, strict reference has been made to the present planned sequence of observations and to the radar settings, including burst and single pulse duration, pulse bandwidth, pulse repetition frequency and all other parameters which may be changed, and possibly optimized, according to the operative mode. The observed surfaces are simulated by a facet model, allowing the generation of surfaces with Gaussian or non-Gaussian roughness statistic, together with the possibility of assigning to the surface an average behaviour which can represent, for instance, a flat surface or a crater. The results of the simulation will be discussed, in order to check the analytical evaluations of the models of the average received echoes and of the attainable performances. In conclusion, the simulation results should allow the validation of the theoretical evaluations of the capabilities of microwave instruments, when

  5. Radar Performance Improvement. Angle Tracking Modification to Fire Control Radar System for Space Shuttle Rendezvous

    NASA Technical Reports Server (NTRS)

    Little, G. R.

    1976-01-01

    The AN/APQ-153 fire control radar modified to provide angle tracking was evaluated for improved performance. The frequency agile modifications are discussed along with the range-rate improvement modifications, and the radar to computer interface. A parametric design and comparison of noncoherent and coherent radar systems are presented. It is shown that the shuttle rendezvous range and range-rate requirements can be made by a Ku-Band noncoherent pulse radar.

  6. Analysis of Tropical Cyclone Eye Slope Using Airborne Radar Reflectivity Data

    NASA Astrophysics Data System (ADS)

    Hazelton, A. T.; Hart, R. E.

    2011-12-01

    Understanding and forecasting tropical cyclone intensity change continues to be one of the biggest challenges in atmospheric research and forecasting. While the large-scale processes that govern TC intensity change (such as wind shear and ocean temperature) are relatively well-understood, the same cannot be said for smaller-scale inner-core processes and structure. For example, while the eyewall of a hurricane is known from observations to tilt outward with increasing height, there is no theory or even robust observational study to explain the magnitude of this tilt or what changes in that tilt signify. The relative lack of observations in the inner-core region has made research difficult for many decades. However, the recent increase in research flights (e.g. GRIP, PREDICT) into the cores of tropical storms has provided data that allows us to better analyze the complex factors that drive changes in the inner-structure of storms. This study makes use of airborne radar reflectivity data from different field experiments and a group of reconnaissance flights into hurricanes to study the vertical structure of the TC inner-core; specifically the slope of the eye. We analyze the relationship between the eye slope and the current storm intensity, and compare our results with the limited previous work on this topic (e.g. Stern and Nolan 2009, Shea and Gray 1973). We also investigate the relationship between the eye slope and the short-term intensity change, with hopes of better understanding the physical processes that result from changes in the eye structure. It is also hoped that this relationship with short-term intensity change may prove valuable in forecasting intensity.

  7. The instrumental principles of MST radars and incoherent scatter radars and the configuration of radar system hardware

    NASA Technical Reports Server (NTRS)

    Roettger, Juergen

    1989-01-01

    The principle of pulse modulation used in the case of coherent scatter radars (MST radars) is discussed. Coherent detection and the corresponding system configuration is delineated. Antenna requirements and design are outlined and the phase-coherent transmitter/receiver system is described. Transmit/receive duplexers, transmitters, receivers, and quadrature detectors are explained. The radar controller, integrator, decoder and correlator design as well as the data transfer and the control and monitoring by the host computer are delineated. Typical operation parameters of some well-known radars are summarized.

  8. Fourth Airborne Geoscience Workshop

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The focus of the workshop was on how the airborne community can assist in achieving the goals of the Global Change Research Program. The many activities that employ airborne platforms and sensors were discussed: platforms and instrument development; airborne oceanography; lidar research; SAR measurements; Doppler radar; laser measurements; cloud physics; airborne experiments; airborne microwave measurements; and airborne data collection.

  9. Signal processing for airborne doppler radar detection of hazardous wind shear as applied to NASA 1991 radar flight experiment data

    NASA Technical Reports Server (NTRS)

    Baxa, Ernest G., Jr.

    1992-01-01

    Radar data collected during the 1991 NASA flight tests have been selectively analyzed to support research directed at developing both improved as well as new algorithms for detecting hazardous low-altitude windshear. Analysis of aircraft attitude data from several flights indicated that platform stability bandwidths were small compared to the data rate bandwidths which should support an assumption that radar returns can be treated as short time stationary. Various approaches at detection of weather returns in the presence of ground clutter are being investigated. Non-coventional clutter rejection through spectrum mode tracking and classification algorithms is a subject of continuing research. Based upon autoregressive modeling of the radar return time sequence, this approach may offer an alternative to overcome errors in conventional pulse-pair estimates. Adaptive filtering is being evaluated as a means of rejecting clutter with emphasis on low signal-to-clutter ratio situations, particularly in the presence of discrete clutter interference. An analysis of out-of-range clutter returns is included to illustrate effects of ground clutter interference due to range aliasing for aircraft on final approach. Data are presented to indicate how aircraft groundspeed might be corrected from the radar data as well as point to an observed problem of groundspeed estimate bias variation with radar antenna scan angle. A description of how recorded clutter return data are mixed with simulated weather returns is included. This enables the researcher to run controlled experiments to test signal processing algorithms. In the summary research efforts involving improved modelling of radar ground clutter returns and a Bayesian approach at hazard factor estimation are mentioned.

  10. Earth Penetration Radar Imaging System (EPRIS)

    NASA Astrophysics Data System (ADS)

    1993-08-01

    The Earth Penetration Radar Imaging System (EPRIS) has been developed and has the capability to detect and locate buried mines, buried ordnance delivered by precision munitions, buried drums, buried waste/contaminants, and geological structures/features. The detected objects or features are mapped in three dimensions with high resolution. This information is then available for integration into a site characterization study. The EPRIS is a significant improvement in non-intrusive sensing and imaging capability. This phase of the EPRIS development has been extremely successful. Coleman Research Corporation (CRC) has implemented significant advances in technology into the EPRIS equipment. The frequency stepped radar sensor design has a very wide dynamic signal range and improved sensitivity over currently available equipment. The two- and three-dimensional image processing algorithms allow high-resolution placement and sizing of buried objects and/or features. The discussions related to the analog-to-digital converter and the spiral antenna, define the source of the dynamic range capability realized by EPRIS. The processing for this new radar makes use of unique synthetic aperature imaging (SAI) algorithms developed by CRC for frequency stepped radar systems. The SAI algorithms are necessary to obtain excellent spatial resolution on objects buried up to seven meters. The sensor signal processing represents a significant improvement in imaging systems. The CRC test facility permitted tests on objects buried up to 2.44 meters.

  11. 29 CFR 1915.85 - Vessel radar and communication systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Working Conditions § 1915.85 Vessel radar and communication systems. (a) The employer shall service each vessel's radar and communication systems in accordance with 29 CFR 1915.89, Control of Hazardous Energy... 29 Labor 7 2012-07-01 2012-07-01 false Vessel radar and communication systems. 1915.85...

  12. 29 CFR 1915.85 - Vessel radar and communication systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Working Conditions § 1915.85 Vessel radar and communication systems. (a) The employer shall service each vessel's radar and communication systems in accordance with 29 CFR 1915.89, Control of Hazardous Energy... 29 Labor 7 2014-07-01 2014-07-01 false Vessel radar and communication systems. 1915.85...

  13. Goldstone Solar System Radar Waveform Generator

    NASA Technical Reports Server (NTRS)

    Quirk, Kevin J.; Patawaran, Ferze D.; Nguyen, Danh H.; Nguyen, Huy

    2012-01-01

    Due to distances and relative motions among the transmitter, target object, and receiver, the time-base between any transmitted and received signal will undergo distortion. Pre-distortion of the transmitted signal to compensate for this time-base distortion allows reception of an undistorted signal. In most radar applications, an arbitrary waveform generator (AWG) would be used to store the pre-calculated waveform and then play back this waveform during transmission. The Goldstone Solar System Radar (GSSR), however, has transmission durations that exceed the available memory storage of such a device. A waveform generator capable of real-time pre-distortion of a radar waveform to a given time-base distortion function is needed. To pre-distort the transmitted signal, both the baseband radar waveform and the RF carrier must be modified. In the GSSR, this occurs at the up-conversion mixing stage to an intermediate frequency (IF). A programmable oscillator (PO) is used to generate the IF along with a time-varying phase component that matches the time-base distortion of the RF carrier. This serves as the IF input to the waveform generator where it is mixed with a baseband radar waveform whose time-base has been distorted to match the given time-base distortion function producing the modulated IF output. An error control feedback loop is used to precisely control the time-base distortion of the baseband waveform, allowing its real-time generation. The waveform generator produces IF modulated radar waveforms whose time-base has been pre-distorted to match a given arbitrary function. The following waveforms are supported: continuous wave (CW), frequency hopped (FH), binary phase code (BPC), and linear frequency modulation (LFM). The waveform generator takes as input an IF with a time varying phase component that matches the time-base distortion of the carrier. The waveform generator supports interconnection with deep-space network (DSN) timing and frequency standards, and

  14. 76 FR 76333 - Notification for Airborne Wind Energy Systems (AWES)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-07

    ... Statement can be found in the Federal Register published on April 11, 2000 (65 FR 19477-19478), as well as... Federal Aviation Administration 14 CFR Part 77 Notification for Airborne Wind Energy Systems (AWES) AGENCY...,'' to airborne wind energy systems (AWES). In addition, this notice requests information from...

  15. A comparison of airborne GEMS/SAR with satellite-borne Seasat/SAR radar imagery - The value of archived multiple data sets

    NASA Technical Reports Server (NTRS)

    Hanson, Bradford C.; Dellwig, Louis F.

    1988-01-01

    In a study concerning the value of using radar imagery from systems with diverse parameters, X-band images of the Northern Louisiana Salt dome area generated by the airborne Goodyear electronic mapping system (GEMS) are analyzed in conjunction with imagery generated by the satelliteborne Seasat/SAR. The GEMS operated with an incidence angle of 75 to 85 deg and a resolution of 12 m, whereas the Seasat/SAR operated with an incidence angle of 23 deg and a resolution of 25 m. It is found that otherwise unattainable data on land management activities, improved delineation of the drainage net, better definition of surface roughness in cleared areas, and swamp identification, became accessible when adjustments for the time lapse between the two missions were made and supporting ground data concerning the physical and vegetative characteristics of the terrain were acquired.

  16. Characteristics of Deep Tropical and Subtropical Convection from Nadir-Viewing High-Altitude Airborne Doppler Radar

    NASA Technical Reports Server (NTRS)

    Heymsfield, Gerald M.; Tian, Lin; Heymsfield, Andrew J.; Li, Lihua; Guimond, Stephen

    2010-01-01

    This paper presents observations of deep convection characteristics in the tropics and subtropics that have been classified into four categories: tropical cyclone, oceanic, land, and sea breeze. Vertical velocities in the convection were derived from Doppler radar measurements collected during several NASA field experiments from the nadir-viewing high-altitude ER-2 Doppler radar (EDOP). Emphasis is placed on the vertical structure of the convection from the surface to cloud top (sometimes reaching 18-km altitude). This unique look at convection is not possible from other approaches such as ground-based or lower-altitude airborne scanning radars. The vertical motions from the radar measurements are derived using new relationships between radar reflectivity and hydrometeor fall speed. Various convective properties, such as the peak updraft and downdraft velocities and their corresponding altitude, heights of reflectivity levels, and widths of reflectivity cores, are estimated. The most significant findings are the following: 1) strong updrafts that mostly exceed 15 m/s, with a few exceeding 30 m/s, are found in all the deep convection cases, whether over land or ocean; 2) peak updrafts were almost always above the 10-km level and, in the case of tropical cyclones, were closer to the 12-km level; and 3) land-based and sea-breeze convection had higher reflectivities and wider convective cores than oceanic and tropical cyclone convection. In addition, the high-resolution EDOP data were used to examine the connection between reflectivity and vertical velocity, for which only weak linear relationships were found. The results are discussed in terms of dynamical and microphysical implications for numerical models and future remote sensors.

  17. Flight Tests of the DELICAT Airborne LIDAR System for Remote Clear Air Turbulence Detection

    NASA Astrophysics Data System (ADS)

    Vrancken, Patrick; Wirth, Martin; Ehret, Gerhard; Witschas, Benjamin; Veerman, Henk; Tump, Robert; Barny, Hervé; Rondeau, Philippe; Dolfi-Bouteyre, Agnès; Lombard, Laurent

    2016-06-01

    An important aeronautics application of lidar is the airborne remote detection of Clear Air Turbulence which cannot be performed with onboard radar. We report on a DLR-developed lidar system for the remote detection of such turbulent areas in the flight path of an aircraft. The lidar, consisting of a high-power UV laser transmitter and a direct detection system, was installed on a Dutch research aircraft. Flight tests executed in 2013 demonstrated the performance of the lidar system to detect local subtle variations in the molecular backscatter coefficient indicating the turbulence some 10 to 15 km ahead.

  18. A multiprocessor airborne lidar data system

    NASA Technical Reports Server (NTRS)

    Wright, C. W.; Bailey, S. A.; Heath, G. E.; Piazza, C. R.

    1988-01-01

    A new multiprocessor data acquisition system was developed for the existing Airborne Oceanographic Lidar (AOL). This implementation simultaneously utilizes five single board 68010 microcomputers, the UNIX system V operating system, and the real time executive VRTX. The original data acquisition system was implemented on a Hewlett Packard HP 21-MX 16 bit minicomputer using a multi-tasking real time operating system and a mixture of assembly and FORTRAN languages. The present collection of data sources produce data at widely varied rates and require varied amounts of burdensome real time processing and formatting. It was decided to replace the aging HP 21-MX minicomputer with a multiprocessor system. A new and flexible recording format was devised and implemented to accommodate the constantly changing sensor configuration. A central feature of this data system is the minimization of non-remote sensing bus traffic. Therefore, it is highly desirable that each micro be capable of functioning as much as possible on-card or via private peripherals. The bus is used primarily for the transfer of remote sensing data to or from the buffer queue.

  19. Laser Docking System Radar flight experiment

    NASA Technical Reports Server (NTRS)

    Erwin, Harry O.

    1986-01-01

    Flight experiments to verify the Laser Docking System Radar are discussed. The docking requirements are summarized, and the breadboarded hardware is described, emphasizing the two major scanning concepts being utilized: a mechanical scanning technique employing galvanometer beamsteerers and an electronic scanning technique using an image dissector. The software simulations used to apply hardware solutions to the docking requirements are briefly discussed, the tracking test bed is described, and the objectives of the flight experiment are reviewed.

  20. A numerical simulation of Hurricane Bret on 22-23 August 1999 initialized with airborne Doppler radar and dropsonde data

    NASA Astrophysics Data System (ADS)

    Nuissier, Olivier; Rogers, Robert F.; Roux, Frank

    2005-01-01

    This study concerns the simulation of Hurricane Bret on 22-23 August 1999 with the MésoNH nonhydrostatic, two-way interactive, quadruple-nested grid mesoscale model. A 30 h integration, from 0000 UTC 22 August to 0600UTC 23 August, covers the period of maximum intensity over the Gulf of Mexico and landfall over Texas. Special attention is paid to the initial conditions from which the model is integrated. A balanced vortex, derived from airborne Doppler radar data, is used to replace the ill-defined cyclone in the large-scale analysis. In addition, the analysed humidity field over the Gulf of Mexico is modified in accordance with specific dropsonde observations. A comparison between the simulated storm track and intensity for three different numerical experiments shows that the inclusion of the radar-derived vortex and high spatial resolution are necessary to obtain a realistic simulation. After an initial period of adjustment, the simulation with the inserted radar-derived vortex and high resolution produces a storm only 10 hPa weaker than the observation after 24 h, compared to the control run that is nearly 50 hPa weaker at the same time. The characteristics of this simulated storm at its mature stage are then presented, with particular emphasis on the processes that modulate the intensity of the inner core region.

  1. Influences of weather phenomena on automotive laser radar systems

    NASA Astrophysics Data System (ADS)

    Rasshofer, R. H.; Spies, M.; Spies, H.

    2011-07-01

    Laser radar (lidar) sensors provide outstanding angular resolution along with highly accurate range measurements and thus they were proposed as a part of a high performance perception system for advanced driver assistant functions. Based on optical signal transmission and reception, laser radar systems are influenced by weather phenomena. This work provides an overview on the different physical principles responsible for laser radar signal disturbance and theoretical investigations for estimation of their influence. Finally, the transmission models are applied for signal generation in a newly developed laser radar target simulator providing - to our knowledge - worldwide first HIL test capability for automotive laser radar systems.

  2. Validation of GPM Ka-Radar Algorithm Using a Ground-based Ka-Radar System

    NASA Astrophysics Data System (ADS)

    Nakamura, Kenji; Kaneko, Yuki; Nakagawa, Katsuhiro; Furukawa, Kinji; Suzuki, Kenji

    2016-04-01

    GPM led by the Japan Aerospace Exploration Agency (JAXA) and the National Aeronautics and Space Administration of US (NASA) aims to observe global precipitation. The core satellite is equipped with a microwave radiometer (GMI) and a dual-frequency radar (DPR) which is the first spaceborne Ku/Ka-band dual-wavelength radar dedicated for precipitation measurement. In the DPR algorithm, measured radar reflectivity is converted to effective radar reflectivity by estimating the rain attenuation. Here, the scattering/attenuation characteristics of Ka-band radiowaves are crucial, particularly for wet snow. A melting layer observation using a dual Ka-band radar system developed by JAXA was conducted along the slope of Mt. Zao in Yamagata Prefecture, Japan. The dual Ka-band radar system consists of two nearly identical Ka-band FM-CW radars, and the precipitation systems between two radars were observed in opposite directions. From this experiment, equivalent radar reflectivity (Ze) and specific attenuation (k) were obtained. The experiments were conducted for two winter seasons. During the data analyses, it was found that k estimate easily fluctuates because the estimate is based on double difference calculation. With much temporal and spatial averaging, k-Ze relationship was obtained for melting layers. One of the results is that the height of the peak of k seems slightly higher than that of Ze. The results are compared with in-situ precipitation particle measurements.

  3. Airborne Tomographic Swath Ice Sounding Processing System

    NASA Technical Reports Server (NTRS)

    Wu, Xiaoqing; Rodriquez, Ernesto; Freeman, Anthony; Jezek, Ken

    2013-01-01

    Glaciers and ice sheets modulate global sea level by storing water deposited as snow on the surface, and discharging water back into the ocean through melting. Their physical state can be characterized in terms of their mass balance and dynamics. To estimate the current ice mass balance, and to predict future changes in the motion of the Greenland and Antarctic ice sheets, it is necessary to know the ice sheet thickness and the physical conditions of the ice sheet surface and bed. This information is required at fine resolution and over extensive portions of the ice sheets. A tomographic algorithm has been developed to take raw data collected by a multiple-channel synthetic aperture sounding radar system over a polar ice sheet and convert those data into two-dimensional (2D) ice thickness measurements. Prior to this work, conventional processing techniques only provided one-dimensional ice thickness measurements along profiles.

  4. Microprocessor-Based Airborne Spectrometer System

    NASA Astrophysics Data System (ADS)

    Kates, John C.

    1980-08-01

    A system for airborne infrared spectral signature measurements has been developed using a Fourier transform spectrometer interfaced to a microprocessor data acquisition, control and display system. The microprocessor is a DEC LSI-ll with 20KW RAM, 4KW EPROM, DMA spectrometer interface, digital magnetic tape, and dot-matrix video graphic display. A real-time executive tailored to the requirements and resources available allows concurrent data acquisition, recording, reduction and display. Using multiple buffers, acquisition of spectrometer data via DMA is overlapped with magnetic tape output. A background task selects the most recent spectrometer data and processes it using an FFT into a raw spectrum. A reference background spectrum is subtracted to isolate the data component, then a reference instrument response function is applied to obtain a calibrated absolute irradiance spectrum. The irradiance spectrum is displayed on the video graphic display and mixed with boresight camera video to show the target spectrum superimposed on the target image. Extensive selftest facilities are incorporated for testing all system components and compatibility with data reduction systems. System calibration is supported by selection of reference blackbody temperatures, apertures, and distances. The instrument response curve obtained during calibration is displayed for verification of correct spectrometer operation or diagnosis of faults.

  5. Summary of flight tests of an airborne lighting locator system and comparison with ground-based measurements of precipitation and turbulence

    NASA Technical Reports Server (NTRS)

    Fisher, B. D.; Crabill, N. L.

    1981-01-01

    Data from an airborne lightning locator system and data relating to storm intensity obtained by ground-based Doppler radars and the S-band research radar are presented. When comparing lightning locations from the airborne lightning locator system with ground-based Doppler radar measurements of reflectivity and spectrum width, the lightning locations tended to be further from the aircraft position than the Doppler radar contours, but at the same relative bearing from the aircraft as the Doppler contours. The results also show that convective storms generate little or no lightning for a significant part of their life cycle, but can produce at least moderate turbulence. Therefore, it is concluded that a lack of lightning activity cannot be accepted as an inference of a corresponding lack of other hazards to the flight of aircraft through convective storms.

  6. Miniaturized Airborne Imaging Central Server System

    NASA Technical Reports Server (NTRS)

    Sun, Xiuhong

    2011-01-01

    In recent years, some remote-sensing applications require advanced airborne multi-sensor systems to provide high performance reflective and emissive spectral imaging measurement rapidly over large areas. The key or unique problem of characteristics is associated with a black box back-end system that operates a suite of cutting-edge imaging sensors to collect simultaneously the high throughput reflective and emissive spectral imaging data with precision georeference. This back-end system needs to be portable, easy-to-use, and reliable with advanced onboard processing. The innovation of the black box backend is a miniaturized airborne imaging central server system (MAICSS). MAICSS integrates a complex embedded system of systems with dedicated power and signal electronic circuits inside to serve a suite of configurable cutting-edge electro- optical (EO), long-wave infrared (LWIR), and medium-wave infrared (MWIR) cameras, a hyperspectral imaging scanner, and a GPS and inertial measurement unit (IMU) for atmospheric and surface remote sensing. Its compatible sensor packages include NASA s 1,024 1,024 pixel LWIR quantum well infrared photodetector (QWIP) imager; a 60.5 megapixel BuckEye EO camera; and a fast (e.g. 200+ scanlines/s) and wide swath-width (e.g., 1,920+ pixels) CCD/InGaAs imager-based visible/near infrared reflectance (VNIR) and shortwave infrared (SWIR) imaging spectrometer. MAICSS records continuous precision georeferenced and time-tagged multisensor throughputs to mass storage devices at a high aggregate rate, typically 60 MB/s for its LWIR/EO payload. MAICSS is a complete stand-alone imaging server instrument with an easy-to-use software package for either autonomous data collection or interactive airborne operation. Advanced multisensor data acquisition and onboard processing software features have been implemented for MAICSS. With the onboard processing for real time image development, correction, histogram-equalization, compression, georeference, and

  7. Summary of Turbulence Data Obtained During United Air Lines Flight Evaluation of an Experimental C Band (5.5 cm) Airborne Weather Radar

    NASA Technical Reports Server (NTRS)

    Coe, E. C.; Fetner, M. W.

    1954-01-01

    Data on atmospheric turbulence in the vicinity of thunderstorms obtained during a flight evaluation of an experimental C band (5.5 cm) airborne radar are summarized. The turbulence data were obtained with an NACA VGH recorder installed in a United Air Lines DC-3 airplane.

  8. Internal wave observations made with an airborne synthetic aperture imaging radar

    NASA Technical Reports Server (NTRS)

    Elachi, C.; Apel, J. R.

    1976-01-01

    Synthetic aperture L-band radar flown aboard the NASA CV-990 has observed periodic striations on the ocean surface off the coast of Alaska which have been interpreted as tidally excited oceanic internal waves of less than 500 m length. These radar images are compared to photographic imagery of similar waves taken from Landsat 1. Both the radar and Landsat images reveal variations in reflectivity across each wave in a packet that range from low to high to normal. The variations point to the simultaneous existence of two mechanisms for the surface signatures of internal waves: roughening due to wave-current interactions, and smoothing due to slick formation.

  9. Challenges to Airborne and Orbital Radar Sounding in the Presence of Surface Clutter: Lessons Learned (so far) from the Dry Valleys of Antarctica

    NASA Astrophysics Data System (ADS)

    Holt, J. W.; Peters, M. E.; Kempf, S. D.; Morse, D. L.; Blankenship, D. D.

    2005-12-01

    The search for life and in-situ resources for exploration on Mars targets both liquid and solid water, whether distributed or in reservoirs. Massive surface ice may cover potential habitats or other features of great interest. Ice-rich layering in the high latitudes holds clues to the climatic history of the planet. Multiple geophysical methods will clearly be necessary to fully characterize these various states of water (and other forms of ice), but radar sounding will be a critical component of the effort. Orbital radar sounders are already being employed and plans for surface-based and suborbital, above-surface radar sounders are being discussed. The difficulties in interpreting data from each type of platform are quite different. Given the lack of existing orbital radar sounding data from any planetary body, the analysis of airborne radar sounding data is quite useful for assessing the advantages and disadvantages of above-surface radar sounding on Mars. In addition to over 300,000 line-km of data collected over the Antarctic ice sheet by airborne radar sounding, we have recently analyzed data from the Dry Valleys of Antarctica where conditions and features emulate Mars in several respects. These airborne radar sounding data were collected over an ice-free area of Taylor Valley, ice-covered lakes, Taylor Glacier, and Beacon Valley. The pulsed radar (52.5 - 67.5 MHz chirp) was coherently recorded. Pulse compression and unfocused SAR processing were applied. One of the most challenging aspects of above-surface radar sounding is the determination of echo sources. This can, of course, be problematic for surface-based radar sounders given possible subsurface scattering geometries, but it is most severe for above-surface sounders because echoes from cross-track surface topography (surface clutter) can have similar time delays to those from the subsurface. We have developed two techniques to accomplish the identification of this surface clutter in single-pass airborne

  10. An approach to evaluating reactive airborne wind shear systems

    NASA Technical Reports Server (NTRS)

    Gibson, Joseph P., Jr.

    1992-01-01

    An approach to evaluating reactive airborne windshear detection systems was developed to support a deployment study for future FAA ground-based windshear detection systems. The deployment study methodology assesses potential future safety enhancements beyond planned capabilities. The reactive airborne systems will be an integral part of planned windshear safety enhancements. The approach to evaluating reactive airborne systems involves separate analyses for both landing and take-off scenario. The analysis estimates the probability of effective warning considering several factors including NASA energy height loss characteristics, reactive alert timing, and a probability distribution for microburst strength.

  11. Past-time Radar Rainfall Estimates using Radar AWS Rainrate system with Local Gauge Correction method

    NASA Astrophysics Data System (ADS)

    Choi, D.; Lee, M. H.; Suk, M. K.; Nam, K. Y.; Hwang, J.; Ko, J. S.

    2015-12-01

    The Weather Radar Center at Korea Meteorological Administration (KMA) has radar network for warnings for heavy rainfall and severe storms. We have been operating an operational real-time adjusted the Radar-Automatic Weather Station (AWS) Rainrate (RAR) system developed by KMA in 2006 for providing radar-based quantitative precipitation estimation (QPE) to meteorologists. This system has several uncertainty in estimating precipitation by radar reflectivity (Z) and rainfall intensity (R) relationship. To overcome uncertainty of the RAR system and improve the accuracy of QPE, we are applied the Local Gauge Correction (LGC) method which uses geo-statistical effective radius of errors of the QPE to RAR system in 2012. According to the results of previous study in 2014 (Lee et al., 2014), the accuracy of the RAR system with LGC method improved about 7.69% than before in the summer season of 2012 (from June to August). It has also improved the accuracy of hydrograph when we examined the accuracy of flood simulation using hydrologic model and data derived by the RAR system with LGC method. We confirmed to have its effectiveness through these results after the application of LGC method. It is required for high quality data of long term to utilize in hydrology field. To provide QPE data more precisely and collect past-time data, we produce that calculated by the RAR system with LGC method in the summer season from 2006 to 2009 and investigate whether the accuracy of past-time radar rainfall estimation enhance or not. Keywords : Radar-AWS Rainrate system, Local gauge correction, past-time Radar rainfall estimation Acknowledgements : This research is supported by "Development and application of Cross governmental dual-pol radar harmonization (WRC-2013-A-1)" project of the Weather Radar Center, Korea Meteorological Administration in 2015.

  12. Solid-state coherent laser radar wind shear measuring systems

    NASA Technical Reports Server (NTRS)

    Huffaker, R. Milton

    1992-01-01

    Coherent Technologies, Inc. (CTI) was established in 1984 to engage in the development of coherent laser radar systems and subsystems with applications in atmospheric remote sensing, and in target tracking, ranging and imaging. CTI focuses its capabilities in three major areas: (1) theoretical performance and design of coherent laser radar system; (2) development of coherent laser radar systems for government agencies such as DoD and NASA; and (3) development of coherent laser radar systems for commercial markets. The topics addressed are: (1) 1.06 micron solid-state coherent laser radar system; (2) wind measurement using 1.06 micron system; and flashlamp-pumped 2.09 micron solid-state coherent laser radar system.

  13. Evolution of a highly dilatant fault zone in the grabens of Canyonlands National Park, Utah/USA - integrating field work, ground penetrating radar and airborne imagery analysis

    NASA Astrophysics Data System (ADS)

    Kettermann, M.; Grützner, C.; van Gent, H. W.; Urai, J. L.; Reicherter, K.; Mertens, J.

    2015-03-01

    The grabens of the Canyonlands National Park are a young and active system of sub-parallel, arcuate grabens, whose evolution is the result of salt movement in the subsurface and a slight regional tilt of the faulted strata. We present results of ground penetrating radar surveys in combination with field observations and analysis of high resolution airborne imagery. GPR data show intense faulting of the Quaternary sediments at the flat graben floors, implying a more complex fault structure than visible at the surface. Direct measurements of heave and throw at several locations to infer fault dips at depth, combined with observations of primary joint surfaces in the upper 100 m suggest a model of the highly dilatant fault geometry in profile. Sinkholes observed in the field as well as in airborne imagery give insights in local massive dilatancy and show where water and sediments are transported underground. Based on correlations of paleosols observed in outcrops and GPR profiles, we argue that the grabens in Canyonlands National Park are either older than previously assumed, or that sedimentation rates were much higher in the Pleistocene.

  14. Evolution of a highly dilatant fault zone in the grabens of Canyonlands National Park, Utah, USA - integrating fieldwork, ground-penetrating radar and airborne imagery analysis

    NASA Astrophysics Data System (ADS)

    Kettermann, M.; Grützner, C.; van Gent, H. W.; Urai, J. L.; Reicherter, K.; Mertens, J.

    2015-07-01

    The grabens of Canyonlands National Park are a young and active system of sub-parallel, arcuate grabens, whose evolution is the result of salt movement in the subsurface and a slight regional tilt of the faulted strata. We present results of ground-penetrating radar (GPR) surveys in combination with field observations and analysis of high-resolution airborne imagery. GPR data show intense faulting of the Quaternary sediments at the flat graben floors, implying a more complex fault structure than visible at the surface. Direct measurements of heave and throw at several locations to infer fault dips at depth, combined with observations of primary joint surfaces in the upper 100 m, suggest a highly dilatant fault geometry. Sinkholes observed in the field as well as in airborne imagery give insights in local dilatancy and show where water and sediments are transported underground. Based on correlations of paleosols observed in outcrops and GPR profiles, we argue that either the grabens in Canyonlands National Park are older than previously assumed or that sedimentation rates were much higher in the Pleistocene.

  15. Airborne antenna coverage requirements for the TCV B-737 aircraft. [for operation with microwave landing systems

    NASA Technical Reports Server (NTRS)

    Southall, W. A., Jr.; White, W. F.

    1978-01-01

    The airborne antenna line of sight look angle requirement for operation with a Microwave Landing System (MLS) was studied. The required azimuth and elevation line of sight look angles from an antenna located on an aircraft to three ground based antenna sites at the Wallops Flight Center (FPS-16 radar, MLS aximuth, and MLS elevation) as the aircraft follows specific approach paths selected as representative of MLS operations at the Denver, Colorado, terminal area are presented. These required azimuth and elevation look angles may be interpreted as basic design requirements for antenna of the TCV B-737 airplane for MLS operations along these selected approach paths.

  16. Azimuthal Signature of Coincidental Brightness Temperature and Normalized Radar Cross-Section Obtained Using Airborne PALS Instrument

    NASA Technical Reports Server (NTRS)

    Colliander, Andreas; Kim, Seungbum; Yueh, Simon; Cosh, Mike; Jackson, Tom; Njoku, Eni

    2010-01-01

    Coincidental airborne brightness temperature (TB) and normalized radar-cross section (NRCS) measurements were carried out with the PALS (Passive and Active L- and S-band) instrument in the SMAPVEX08 (SMAP Validation Experiment 2008) field campaign. This paper describes results obtained from a set of flights which measured a field in 45(sup o) steps over the azimuth angle. The field contained mature soy beans with distinct row structure. The measurement shows that both TB and NRCS experience modulation effects over the azimuth as expected based on the theory. The result is useful in development and validation of land surface parameter forward models and retrieval algorithms, such as the soil moisture algorithm for NASA's SMAP (Soil Moisture Active and Passive) mission. Although the footprint of the SMAP will not be sensitive to the small resolution scale effects as the one presented in this paper, it is nevertheless important to understand the effects at smaller scale.

  17. Development of a new airborne humidigraph system.

    SciTech Connect

    Pekour, Mikhail S.; Schmid, Beat; Chand, Duli; Hubbe, John M.; Kluzek, Celine D.; Nelson, Danny A.; Tomlinson, Jason M.; Cziczo, Daniel J.

    2012-12-06

    Modeling and measurements of aerosol properties is complicated by the hygroscopic behavior of the aerosols adding significant uncertainty to our best estimates of the direct effect aerosols exert on the radiative balance of the atmosphere. Airborne measurements of aerosol hygroscopicity are particularly challenging but critically needed. This motivated the development of a newly designed system which can measure the dependence of the aerosol light scattering coefficient (σsp) on relative humidity (RH), known as f(RH), in real-time at a rapid rate (<10 s) on an aerial platform. The new system has several advantages over existing systems. It consists of three integrating nephelometers and humidity conditioners for simultaneous measurement of the σsp at three different RHs. The humidity is directly controlled in exchanger cells without significant temperature disturbances and without particle dilution, heating or loss of volatile compounds. The single-wavelength nephelometers are illuminated by LED-based light sources thereby minimizing heating of the sample stream. The flexible design of the RH conditioners, consisting of a number of specially designed exchanger cells (driers or humidifiers), enables us to measure f(RH) under hydration or dehydration conditions (always starting with the aerosol in a known state) with a simple system re-configuration. These exchanger cells have been characterized for losses of particles using latex spheres and laboratory generated ammonium sulfate aerosols. Residence times of 6 - 9 s in the exchangers and subsequent lines is sufficient for most aerosols to attain equilibrium with the new water vapor content. The performance of this system has been assessed aboard DOE’s G-1 research aircraft during test flights over California, Oregon, and Washington.

  18. Combined VHF Dopplar radar and airborne (CV-990) measurements of atmospheric winds on the mesoscale

    NASA Technical Reports Server (NTRS)

    Fairall, Christopher W.; Thomson, Dennis W.

    1989-01-01

    Hourly measurements of wind speed and direction obtained using two wind profiling Doppler radars during two prolonged jet stream occurrences over western Pennsylvania were analyzed. In particular, the time-variant characteristics of derived shear profiles were examined. To prevent a potential loss of structural detail and retain statistical significance, data from both radars were stratified into categories based on the location data from the Penn State radar were also compared to data from Pittsburgh radiosondes. Profiler data dropouts were studied in an attempt to determine possible reasons for the apparently reduced performance of profiling radars operating beneath a jet stream. Temperature profiles for the radar site were obtained using an interpolated temperature and dewpoint temperature sounding procedure developed at Penn State. The combination of measured wind and interpolated temperature profiles allowed Richardson number profiles to be generated for the profiler sounding volume. Both Richardson number and wind shear statistics were then examined along with pilot reports of turbulence in the vicinity of the profiler.

  19. Airborne optical tracking control system design study

    NASA Astrophysics Data System (ADS)

    1992-09-01

    The Kestrel LOS Tracking Program involves the development of a computer and algorithms for use in passive tracking of airborne targets from a high altitude balloon platform. The computer receivers track error signals from a video tracker connected to one of the imaging sensors. In addition, an on-board IRU (gyro), accelerometers, a magnetometer, and a two-axis inclinometer provide inputs which are used for initial acquisitions and course and fine tracking. Signals received by the control processor from the video tracker, IRU, accelerometers, magnetometer, and inclinometer are utilized by the control processor to generate drive signals for the payload azimuth drive, the Gimballed Mirror System (GMS), and the Fast Steering Mirror (FSM). The hardware which will be procured under the LOS tracking activity is the Controls Processor (CP), the IRU, and the FSM. The performance specifications for the GMS and the payload canister azimuth driver are established by the LOS tracking design team in an effort to achieve a tracking jitter of less than 3 micro-rad, 1 sigma for one axis.

  20. Assessment of lightweight mobile nuclear power systems. [for airborne vehicles

    NASA Technical Reports Server (NTRS)

    Anderson, J. L.; Rom, F. E.

    1973-01-01

    A review was made of lightweight mobile nuclear power systems (LMNPS). Data cover technical feasibility studies of LMNPS and airborne vehicles, mission studies, and non-technical conditions that are required to develop and use LMNPS.

  1. Airborne Visible Laser Optical Communications Program (AVLOC)

    NASA Technical Reports Server (NTRS)

    Ward, J. H.

    1975-01-01

    The design, development, and operation of airborne and ground-based laser communications and laser radar hardware is described in support of the Airborne Visible Laser Optical Communication program. The major emphasis is placed on the development of a highly flexible test bed for the evaluation of laser communications systems techniques and components in an operational environment.

  2. Power line characterization from an airborne data collection with a millimeter wave radar

    NASA Astrophysics Data System (ADS)

    Goshi, Darren S.; Bui, Long Q.

    2014-05-01

    Enhancing the operational safety of small, maneuverable rotorcraft has been a critical consideration in the development of next generation situational awareness sensor suites. From landing assistance to target detection and obstacle avoidance, millimeter wave radars have become the leading candidate for such solutions due to their ability to operate in degraded visual environments, whether it is weather, induced debris, or night conditions that must be dealt with. Power lines pose arguably the largest safety risk for helicopter operation due to their difficulty in detection and proper identification to support avoidance maneuvering, where even under perfect conditions they can be nearly invisible to the naked eye. The backscatter phenomenology from braided power lines has been well-studied and formulated in previous literature, albeit mainly in controlled laboratory settings or limited field trials. Subsequently, the ability to simply detect power lines at operational distances up to around 2 km has been demonstrated. In this work, an analysis is performed on the measureable characteristics of power lines captured in a representative operational environment for helicopters. The test location included a diverse set of power line configurations with surrounding ground and tower clutter, representing a realistic scenario. A radiometrically calibrated w-band real-beam FMCW sensor allows the study and estimation of target RCS, as well as evaluation against the developed theory. All analysis is performed on dynamically captured data from a helicopter, where platform dynamics and system stability also play a significant role in a processed result. Results from this work will aid the effective development of next generation situational awareness systems.

  3. Radar systems for the water resources mission, volume 1

    NASA Technical Reports Server (NTRS)

    Moore, R. K.; Claassen, J. P.; Erickson, R. L.; Fong, R. K. T.; Hanson, B. C.; Komen, M. J.; Mcmillan, S. B.; Parashar, S. K.

    1976-01-01

    The state of the art determination was made for radar measurement of: soil moisture, snow, standing and flowing water, lake and river ice, determination of required spacecraft radar parameters, study of synthetic-aperture radar systems to meet these parametric requirements, and study of techniques for on-board processing of the radar data. Significant new concepts developed include the following: scanning synthetic-aperture radar to achieve wide-swath coverage; single-sideband radar; and comb-filter range-sequential, range-offset SAR processing. The state of the art in radar measurement of water resources parameters is outlined. The feasibility for immediate development of a spacecraft water resources SAR was established. Numerous candidates for the on-board processor were examined.

  4. The absolute amplitude calibration of the SEASAT synthetic aperture radar - An intercomparison with other L-band radar systems

    NASA Technical Reports Server (NTRS)

    Held, D.; Werner, C.; Wall, S.

    1983-01-01

    The absolute amplitude calibration of the spaceborne Seasat SAR data set is presented based on previous relative calibration studies. A scale factor making it possible to express the perceived radar brightness of a scene in units of sigma-zero is established. The system components are analyzed for error contribution, and the calibration techniques are introduced for each stage. These include: A/D converter saturation tests; prevention of clipping in the processing step; and converting the digital image into the units of received power. Experimental verification was performed by screening and processing the data of the lava flow surrounding the Pisgah Crater in Southern California, for which previous C-130 airborne scatterometer data were available. The average backscatter difference between the two data sets is estimated to be 2 dB in the brighter, and 4 dB in the dimmer regions. For the SAR a calculated uncertainty of 3 dB is expected.

  5. Impact of assimilating airborne Doppler radar velocity data using the ARPS 3DVAR on the analysis and prediction of Hurricane Ike (2008)

    NASA Astrophysics Data System (ADS)

    Du, Ningzhu; Xue, Ming; Zhao, Kun; Min, Jinzhong

    2012-09-01

    The ARPS 3DVAR data assimilation system is enhanced and used for the first time to assimilate airborne Doppler radar wind observations. It is applied to Hurricane Ike (2008), where radar observations taken along four flight legs through the hurricane vortex 14 to 18 h before it made landfall are assimilated. An optimal horizontal de-correlation scale for the background error is determined through sensitivity experiments. A comparison is made between assimilating retrieved winds and assimilating radial velocity data directly. The effect of the number of assimilation cycles, each analyzing data from one flight leg, is also examined. The assimilation of retrieved wind data and of radial velocity data produces similar results. However, direct assimilation of radial velocity data is recommended for both theoretical and practical reasons. In both cases, velocity data assimilation improves the analyzed hurricane structure and intensity as well as leads to better prediction of the intensity. Improvement to the track forecasting is also found. The assimilation of radial velocity observations from all four flight legs through intermittent assimilation cycles produces the best analyses and forecasts. The first analysis in the first cycle tends to produce the largest analysis increment. It is through the mutual adjustments among model variables during the forecast periods that a balanced vortex with lowered central pressure is established. The wind speeds extracted from the assimilated model state agree very well with independent surface wind measurements by the stepped-frequency microwave radiometer onboard the aircraft, and with independent flight-level wind speeds detected by the NOAA P-3 aircraft in-flight measurements. Twenty-four hour accumulated precipitation is noticeably improved over the case without radar data assimilation.

  6. The USGS Side-Looking Airborne Radar (SLAR) program: CD-ROMs expand potential for petroleum exploration

    SciTech Connect

    Kover, A.N.; Schoonmaker, J.W. Jr.; Pohn. H.A. )

    1991-03-01

    The United States Geological Survey (USGS) began the systematic collection of Side-Looking Airborne Radar (SLAR) data in 1980. The SLAR image data, useful for many geologic applications including petroleum exploration, are compiled into mosaics using the USGS 1:250,000-scale topographic map series for format and control. Mosaics have been prepared for over 35% of the United States. Image data collected since 1985 are also available as computer compatible tapes (CCTs) for digital analysis. However, the use of tapes is often cumbersome. To make digital data more readily available for use on a microcomputer, the USGS has started to prepare compact discs-read only memory (CD-ROM). Several experimental discs have been compiled to demonstrate the utility of the medium to make available very large data sets. These discs include necessary nonproprietary software text, radar, and other image data. The SLAR images selected for these discs show significantly different geologic features and include the Long Valley caldera, a section of the San Andreas fault in the Monterey area, the Grand Canyon, and glaciers in southeastern Alaska. At present, several CD-ROMs are available as standard products distributed by the USGS EROS Data Center in Sioux Falls, South Dakota 57198. This is also the source for all USGS SLAR photographic and digital material.

  7. Analysis of volcanic surface morphology on Venus from comparison of Arecibo, Magellan, and terrestrial airborne radar data

    NASA Technical Reports Server (NTRS)

    Campbell, Bruce A.; Campbell, Donald B.

    1992-01-01

    The paper compares Arecibo Observatory and Magellan radar data for Venus to airborne radar images for potential terrestrial analog surfaces. Volcanic deposits in western Eistla Regio and northern Sedna Planitia are characterized. It is shown that the expected-sense circularly polarized echoes in the 'dark plains' and broad flow aprons of Eistla Regio decrease rapidly with incidence angle. This angular scattering behavior implies surfaces no rougher than terrestrial pahoehoe flows. Polarization ratio comparisons show that the extensive lava flows in Western Eistla Regio and Sedna Planitia are generally consistent with the properties of terrestrial pahoehoe flows, with only limited occurrences of a'a morphology. Three scenarios are suggested. Many of the large flow units in the two study regions were emplaced as complexes of low-effusion rate pahoehoe flows, rather than as higher eruption rate events which might be expected to produce a'a surface textures; the long lava flows were originally emplaced as a'a but have since weathered to a smoother texture; or a combination of atmospheric and magma compositional effects combine to inhibit a'a formation even at high volume eruption rates.

  8. Measurement of Attenuation with Airborne and Ground-Based Radar in Convective Storms Over Land and Its Microphysical Implications

    NASA Technical Reports Server (NTRS)

    Tian, Lin; Heymsfield, G. M.; Srivastava, R. C.; Starr, D. OC. (Technical Monitor)

    2001-01-01

    Observations by the airborne X-band Doppler radar (EDOP) and the NCAR S-band polarimetric (S-POL) radar from two field experiments are used to evaluate the Surface ref'ercnce technique (SRT) for measuring the path integrated attenuation (PIA) and to study attenuation in deep convective storms. The EDOP, flying at an altitude of 20 km, uses a nadir beam and a forward pointing beam. It is found that over land, the surface scattering cross-section is highly variable at nadir incidence but relatively stable at forward incidence. It is concluded that measurement by the forward beam provides a viable technique for measuring PIA using the SRT. Vertical profiles of peak attenuation coefficient are derived in vxo deep convective storms by the dual-wavelength method. Using the measured Doppler velocity, the reflectivities at. the two wavelengths, the differential reflectivity and the estimated attenuation coefficients, it is shown that: supercooled drops and dry ice particles probably co-existed above the melting level in regions of updraft, that water-coated partially melted ice particles probably contributed to high attenuation below the melting level, and that the data are not readil explained in terms of a gamma function raindrop size distribution.

  9. Measurement of Attenuation with Airborne and Ground-Based Radar in Convective Storms Over Land Its Microphysical Implications

    NASA Technical Reports Server (NTRS)

    Tian, Lin; Heymsfield, G. M.; Srivastava, R. C.; O'C.Starr, D. (Technical Monitor)

    2001-01-01

    Observations by the airborne X-band Doppler radar (EDOP) and the NCAR S-band polarimetric (S-Pol) radar from two field experiments are used to evaluate the surface reference technique (SRT) for measuring the path integrated attenuation (PIA) and to study attenuation in deep convective storms. The EDOP, flying at an altitude of 20 km, uses a nadir beam and a forward pointing beam. It is found that over land, the surface scattering cross-section is highly variable at nadir incidence but relatively stable at forward incidence. It is concluded that measurement by the forward beam provides a viable technique for measuring PIA using the SRT. Vertical profiles of peak attenuation coefficient are derived in two deep convective storms by the dual-wavelength method. Using the measured Doppler velocity, the reflectivities at the two wavelengths, the differential reflectivity and the estimated attenuation coefficients, it is shown that: supercooled drops and (dry) ice particles probably co-existed above the melting level in regions of updraft, that water-coated partially melted ice particles probably contributed to high attenuation below the melting level.

  10. Ice-volcano interactions during the 2010 Eyjafjallajökull eruption, as revealed by airborne imaging radar

    NASA Astrophysics Data System (ADS)

    Magnússon, E.; Gudmundsson, M. T.; Roberts, M. J.; Sigurã°Sson, G.; HöSkuldsson, F.; Oddsson, B.

    2012-07-01

    During the eruption of the ice-covered Eyjafjallajökull volcano, a series of images from an airborne Synthetic Aperture Radar (SAR) were obtained by the Icelandic Coast Guard. Cloud obscured the summit from view during the first three days of the eruption, making the weather-independent SAR a valuable monitoring resource. Radar images revealed the development of ice cauldrons in a 200 m thick ice cover within the summit caldera, as well as the formation of cauldrons to the immediate south of the caldera. Additionally, radar images were used to document the subglacial and supraglacial passage of floodwater to the north and south of the eruption site. The eruption breached the ice surface about four hours after its onset at about 01:30 UTC on 14 April 2010. The first SAR images, obtained between 08:55 and 10:42 UTC, show signs of limited supraglacial drainage from the eruption site. Floodwater began to drain from the ice cap almost 5.5 h after the beginning of the eruption, implying storage of meltwater at the eruption site due to initially constricted subglacial drainage from the caldera. Heat transfer rates from magma to ice during early stages of cauldron formation were about 1 MW m-2 in the radial direction and about 4 MW m-2 vertically. Meltwater release was characterized by accumulation and drainage with most of the volcanic material in the ice cauldrons being drained in hyperconcentrated floods. After the third day of the eruption, meltwater generation at the eruption site diminished due to an insulating lag of tephra.

  11. Feasibility of inter-comparing airborne and spaceborne obsevations of radar backscattering coefficients

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive (SMAP) mission will provide global soil moisture products that will facilitate new science and application areas. The SMAP mission, scheduled for launch in November 2014, will offer synthetic aperture radar (SAR) measurements of backscattering coefficients for the re...

  12. Study to investigate and evaluate means of optimizing the radar function. [systems engineering of pulse radar for the space shuttle

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The investigations for a rendezvous radar system design and an integrated radar/communication system design are presented. Based on these investigations, system block diagrams are given and system parameters are optimized for the noncoherent pulse and coherent pulse Doppler radar modulation types. Both cooperative (transponder) and passive radar operation are examined including the optimization of the corresponding transponder design for the cooperative mode of operation.

  13. Multi-Antenna Radar Systems for Doppler Rain Measurements

    NASA Technical Reports Server (NTRS)

    Durden, Stephen; Tanelli, Simone; Siqueira, Paul

    2007-01-01

    Use of multiple-antenna radar systems aboard moving high-altitude platforms has been proposed for measuring rainfall. The basic principle of the proposed systems is a variant of that of along-track interferometric synthetic-aperture radar systems used previously to measure ocean waves and currents.

  14. NASA airborne radar wind shear detection algorithm and the detection of wet microbursts in the vicinity of Orlando, Florida

    NASA Technical Reports Server (NTRS)

    Britt, Charles L.; Bracalente, Emedio M.

    1992-01-01

    The algorithms used in the NASA experimental wind shear radar system for detection, characterization, and determination of windshear hazard are discussed. The performance of the algorithms in the detection of wet microbursts near Orlando is presented. Various suggested algorithms that are currently being evaluated using the flight test results from Denver and Orlando are reviewed.

  15. A FMCW Radar Ranging Device for the Teleoperator Maneuvering System

    NASA Technical Reports Server (NTRS)

    Mcdonald, M. W.

    1983-01-01

    A frequency-modulated continuous wave radar system is under development in the Communications Systems Branch of the Information and Electronic Systems Laboratory at Marshall Space Flight Center. The radar unit is being designed for use on the teleoperator maneuvering system. Its function is to provide millimeter-level accuracy in range and range rate measurements out to a range of thirty meters. This will facilitate soft docking with accuracy. This report is an updating of previous developments reported on this system. An innovation in the system is the utilization of a standard reference signal generated by shunting a portion of the radar energy into a shorted coaxial delay line. The regular radar target return signal is constantly compared with the reference signal to provide internal error compensation. Within a five meter range, a limit imposed by present laboratory dimensions, the radar system exhibits reliable accuracy with range error less than 0.2%.

  16. Rain Fallspeeds and Rates Derived from Airborne Nadir-Pointing Doppler Radar Measurements

    NASA Technical Reports Server (NTRS)

    Heymsfield, Gerald M.; Tian, L.; Geerts, Bart

    1999-01-01

    The use of vertical-incidence Doppler velocity in addition to radar reflectivity may yield information on drop size distribution and therefore result in better rainrate estimates. Doppler velocity can provide useful information on the raindrop size distribution. Doppler velocities from a zenith-pointing radar represent the sum of the mean reflectivity-weighted hydrometeor fallspeed and the vertical air motion. Dual-parameter rain estimation methods using the Doppler velocity, require that the latter can be removed, or is negligible. Atlas et al. (1972) derived relations between Doppler velocity, reflectivity, and rain rate assuming an exponential size distribution for rain. Ulbrich (1994) expanded on this work by deriving the relation between the Doppler velocity and the reflectivity assuming a Gamma size distribution. This distribution provides a more realistic representation of the small rain drops. To get accurate information on raindrop size distributions with the above method, the air motions must be removed from the observed Doppler velocities

  17. Improving crop classification through attention to the timing of airborne radar acquisitions

    NASA Technical Reports Server (NTRS)

    Brisco, B.; Ulaby, F. T.; Protz, R.

    1984-01-01

    Radar remote sensors may provide valuable input to crop classification procedures because of (1) their independence of weather conditions and solar illumination, and (2) their ability to respond to differences in crop type. Manual classification of multidate synthetic aperture radar (SAR) imagery resulted in an overall accuracy of 83 percent for corn, forest, grain, and 'other' cover types. Forests and corn fields were identified with accuracies approaching or exceeding 90 percent. Grain fields and 'other' fields were often confused with each other, resulting in classification accuracies of 51 and 66 percent, respectively. The 83 percent correct classification represents a 10 percent improvement when compared to similar SAR data for the same area collected at alternate time periods in 1978. These results demonstrate that improvements in crop classification accuracy can be achieved with SAR data by synchronizing data collection times with crop growth stages in order to maximize differences in the geometric and dielectric properties of the cover types of interest.

  18. Airborne radar imaging of subaqueous channel evolution in Wax Lake Delta, Louisiana, USA

    NASA Astrophysics Data System (ADS)

    Shaw, John B.; Ayoub, Francois; Jones, Cathleen E.; Lamb, Michael P.; Holt, Benjamin; Wagner, R. Wayne; Coffey, Thomas S.; Chadwick, J. Austin; Mohrig, David

    2016-05-01

    Shallow coastal regions are among the fastest evolving landscapes but are notoriously difficult to measure with high spatiotemporal resolution. Using Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) data, we demonstrate that high signal-to-noise L band synthetic aperture radar (SAR) can reveal subaqueous channel networks at the distal ends of river deltas. Using 27 UAVSAR images collected between 2009 and 2015 from the Wax Lake Delta in coastal Louisiana, USA, we show that under normal tidal conditions, planform geometry of the distributary channel network is frequently resolved in the UAVSAR images, including ~700 m of seaward network extension over 5 years for one channel. UAVSAR also reveals regions of subaerial and subaqueous vegetation, streaklines of biogenic surfactants, and what appear to be small distributary channels aliased by the survey grid, all illustrating the value of fine resolution, low noise, L band SAR for mapping the nearshore subaqueous delta channel network.

  19. Precipitating Snow Retrievals from Combined Airborne Cloud Radar and Millimeter-Wave Radiometer Observations

    NASA Technical Reports Server (NTRS)

    Grecu, Mircea; Olson, William S.

    2008-01-01

    An algorithm for retrieving snow over oceans from combined cloud radar and millimeter-wave radiometer observations is developed. The algorithm involves the use of physical models to simulate cloud radar and millimeter-wave radiometer observations from basic atmospheric variables such as hydrometeor content, temperature, and relative humidity profiles and is based on an optimal estimation technique to retrieve these variables from actual observations. A high-resolution simulation of a lake-effect snowstorm by a cloud-resolving model is used to test the algorithm. That is, synthetic observations are generated from the output of the cloud numerical model, and the retrieval algorithm is applied to the synthetic data. The algorithm performance is assessed by comparing the retrievals with the reference variables used in synthesizing the observations. The synthetic observation experiment indicates good performance of the retrieval algorithm. The algorithm is also applied to real observations from the Wakasa Bay field experiment that took place over the Sea of Japan in January and February 2003. The application of the retrieval algorithm to data from the field experiment yields snow estimates that are consistent with both the cloud radar and radiometer observations.

  20. UAVSAR: A New NASA Airborne SAR System for Science and Technology Research

    NASA Technical Reports Server (NTRS)

    Rosen, Paul A.; Hensley, Scott; Wheeler, Kevin; Sadowy, Greg; Miller, Tim; Shaffer, Scott; Muellerschoen, Ron; Jones, Cathleen; Zebker, Howard; Madsen, Soren

    2006-01-01

    NASA's Jet Propulsion Laboratory is currently building a reconfigurable, polarimetric L-band synthetic aperture radar (SAR), specifically designed to acquire airborne repeat track SAR data for differential interferometric measurements. Differentian interferometry can provide key deformation measurements, important for studies of earthquakes, volcanoes and other dynamically changing phenomena. Using precision real-time GPS and a sensor controlled flight management system, the system will be able to fly predefined paths with great precision. The expected performance of the flight control system will constrain the flight path to be within a 10 m diameter tube about the desired flight track. The radar will be designed to be operable on a UAV (Unpiloted Aria1 Vehicle) but will initially be demonstrated on a NASA Gulfstream III. The radar will be fully polarimetric, with a range bandwidth of 80 MHz (2 m range resolution), and will support a 16 km range swath. The antenna will be electronically steered along track to assure that the antenna beam can be directed independently, regardless of the wind direction and speed. Other features supported by the antenna include elevation monopulse and pulse-to-pulse re-steering capabilities that will enable some novel modes of operation. The system will nominally operate at 45,000 ft (13800 m). The program began as an Instrument Incubator Project (IIP) funded by NASA Earth Science and Technology Office (ESTO).

  1. Development of Radar Control system for Multi-mode Active Phased Array Radar for atmospheric probing

    NASA Astrophysics Data System (ADS)

    Yasodha, Polisetti; Jayaraman, Achuthan; Thriveni, A.

    2016-07-01

    Modern multi-mode active phased array radars require highly efficient radar control system for hassle free real time radar operation. The requirement comes due to the distributed architecture of the active phased array radar, where each antenna element in the array is connected to a dedicated Transmit-Receive (TR) module. Controlling the TR modules, which are generally few hundreds in number, and functioning them in synchronisation, is a huge task during real time radar operation and should be handled with utmost care. Indian MST Radar, located at NARL, Gadanki, which is established during early 90's, as an outcome of the middle atmospheric program, is a remote sensing instrument for probing the atmosphere. This radar has a semi-active array, consisting of 1024 antenna elements, with limited beam steering, possible only along the principle planes. To overcome the limitations and difficulties, the radar is being augmented into fully active phased array, to accomplish beam agility and multi-mode operations. Each antenna element is excited with a dedicated 1 kW TR module, located in the field and enables to position the radar beam within 20° conical volume. A multi-channel receiver makes the radar to operate in various modes like Doppler Beam Swinging (DBS), Spaced Antenna (SA), Frequency Domain Interferometry (FDI) etc. Present work describes the real-time radar control (RC) system for the above described active phased array radar. The radar control system consists of a Spartan 6 FPGA based Timing and Control Signal Generator (TCSG), and a computer containing the software for controlling all the subsystems of the radar during real-time radar operation and also for calibrating the radar. The main function of the TCSG is to generate the control and timing waveforms required for various subsystems of the radar. Important components of the RC system software are (i) TR module configuring software which does programming, controlling and health parameter monitoring of the

  2. Development of Radar Control system for Multi-mode Active Phased Array Radar for atmospheric probing

    NASA Astrophysics Data System (ADS)

    Yasodha, Polisetti; Jayaraman, Achuthan; Thriveni, A.

    2016-07-01

    Modern multi-mode active phased array radars require highly efficient radar control system for hassle free real time radar operation. The requirement comes due to the distributed architecture of the active phased array radar, where each antenna element in the array is connected to a dedicated Transmit-Receive (TR) module. Controlling the TR modules, which are generally few hundreds in number, and functioning them in synchronisation, is a huge task during real time radar operation and should be handled with utmost care. Indian MST Radar, located at NARL, Gadanki, which is established during early 90's, as an outcome of the middle atmospheric program, is a remote sensing instrument for probing the atmosphere. This radar has a semi-active array, consisting of 1024 antenna elements, with limited beam steering, possible only along the principle planes. To overcome the limitations and difficulties, the radar is being augmented into fully active phased array, to accomplish beam agility and multi-mode operations. Each antenna element is excited with a dedicated 1 kW TR module, located in the field and enables to position the radar beam within 20° conical volume. A multi-channel receiver makes the radar to operate in various modes like Doppler Beam Swinging (DBS), Spaced Antenna (SA), Frequency Domain Interferometry (FDI) etc. Present work describes the real-time radar control (RC) system for the above described active phased array radar. The radar control system consists of a Spartan 6 FPGA based Timing and Control Signal Generator (TCSG), and a computer containing the software for controlling all the subsystems of the radar during real-time radar operation and also for calibrating the radar. The main function of the TCSG is to generate the control and timing waveforms required for various subsystems of the radar. Important components of the RC system software are (i) TR module configuring software which does programming, controlling and health parameter monitoring of the

  3. Annual Greenland accumulation derived from airborne radar and comparisons to modeled and in situ data

    NASA Astrophysics Data System (ADS)

    Koenig, L.; Ivanoff, A.; Alexander, P. M.; MacGregor, J. A.; Cullather, R. I.; Nowicki, S.

    2015-12-01

    Mass loss across the Greenland Ice Sheet (GrIS) has accelerated in recent decades and recently a fundamental change in the nature of this mass loss has begun. The dominant GrIS mass-loss process has switched from ice dynamics to surface mass balance (SMB) processes, including melt generation and runoff. This recent shift further emphasizes the need to monitor and constrain SMB, which, across most of the GrIS, is dominated by accumulation. High resolution, near-surface radar data have shown good fidelity at mapping spatial patterns of accumulation to validate model outputs. To better constrain accumulation over the GrIS, we derive annual accumulation rates using NASA Operation IceBridge (OIB) Snow Radar data collected from 2009 through 2012. Accumulation is calculated using the radar-determined depth to an annual layer and the local snow/firn density profile. Up to 30 years of annual stratigraphy is observed in the interior of the ice sheet, near Summit Station, while only the past year is detectable in the ablation zone around the perimeter of the ice sheet. Annual layering is traced using a semi-automatic algorithm and mapped across large areas (tens of thousands of line kilometers). A combined measured and modeled density profile is used to convert the annual stratigraphy into accumulation. Modeled density profiles from the Modèle Atmosphérique Régional (MAR) model are shown to be less than half of in situ observations in the top 1 m of snow/firn and are, therefore, replaced with in situ measurements. Using a compilation of in situ measurements, the mean GrIS snow/firn density is found to be ~340 +/- 40 kg/m3 in the top 1 m. Error in the snow density profile represents the largest error in the radar-derived accumulation. The pattern of radar-derived accumulation rate compares well with MAR estimates, although the latter has a mean bias of 4.6 cm water equivalent, a root mean square error of 16.8 cm water equivalent and a correlation coefficient of 0.6 across

  4. HiVision millimeter-wave radar for enhanced vision systems in civil and military transport aircraft

    NASA Astrophysics Data System (ADS)

    Pirkl, Martin; Tospann, Franz-Jose

    1997-06-01

    This paper presents a guideline to meet the requirements of forward looking sensors of an enhanced vision system for both military and civil transport aircraft. It gives an update of a previous publication with special respect to airborne application. For civil transport aircraft an imaging mm-wave radar is proposed as the vision sensor for an enhanced vision system. For military air transport an additional high-performance weather radar should be combined with the mm-wave radar to enable advanced situation awareness, e.g. spot-SAR or air to air operation. For tactical navigation the mm-wave radar is useful due to its ranging capabilities. To meet these requirements the HiVision radar was developed and tested. It uses a robust concept of electronic beam steering and will meet the strict price constraints of transport aircraft. Advanced image processing and high frequency techniques are currently developed to enhance the performance of both the radar image and integration techniques. The advantages FMCW waveform even enables a sensor with low probability of intercept and a high resistance against jammer. The 1997 highlight will be the optimizing of the sensor and flight trials with an enhanced radar demonstrator.

  5. Design of integrated ship monitoring system using SAR, RADAR, and AIS

    NASA Astrophysics Data System (ADS)

    Yang, Chan-Su; Kim, Tae-Ho; Hong, Danbee; Ahn, Hyung-Wook

    2013-06-01

    When we talk about for the ship detection, identification and its classification, we need to go for the wide area of monitoring and it may be possible only through satellite based monitoring approach which monitors and covers coastal as well as the oceanic zone. Synthetic aperture radar (SAR) has been widely used to detect targets of interest with the advantage of the operating capability in all weather and luminance free condition (Margarit and Tabasco, 2011). In EU waters, EMSA(European Maritime Safety Agency) is operating the SafeSeaNet and CleanSeaNet systems which provide the current positions of all ships and oil spill monitoring information in and around EU waters in a single picture to Member States using AIS, LRIT and SAR images. In many countries, a similar system has been developed and the key of the matter is to integrate all available data. This abstract describes the preliminary design concept for an integration system of RADAR, AIS and SAR data for vessel traffic monitoring. SAR sensors are used to acquire image data over large coverage area either through the space borne or airborne platforms in UTC. AIS reports should be also obtained on the same date as of the SAR acquisition for the purpose to perform integration test. Land-based RADAR can provide ships positions detected and tracked in near real time. In general, SAR are used to acquire image data over large coverage area, AIS reports are obtained from ship based transmitter, and RADAR can monitor continuously ships for a limited area. In this study, we developed individual ship monitoring algorithms using RADAR(FMCW and Pulse X-band), AIS and SAR(RADARSAT-2 Full-pol Mode). We conducted field experiments two times for displaying the RADAR, AIS and SAR integration over the Pyeongtaek Port, South Korea.

  6. Airborne multisensor pod system (AMPS) data: Multispectral data integration and processing hints

    SciTech Connect

    Leary, T.J.; Lamb, A.

    1996-11-01

    The Department of Energy`s Office of Arms Control and Non-Proliferation (NN-20) has developed a suite of airborne remote sensing systems that simultaneously collect coincident data from a US Navy P-3 aircraft. The primary objective of the Airborne Multisensor Pod System (AMPS) Program is {open_quotes}to collect multisensor data that can be used for data research, both to reduce interpretation problems associated with data overload and to develop information products more complete than can be obtained from any single sensor.{close_quotes} The sensors are housed in wing-mounted pods and include: a Ku-Band Synthetic Aperture Radar; a CASI Hyperspectral Imager; a Daedalus 3600 Airborne Multispectral Scanner; a Wild Heerbrugg RC-30 motion compensated large format camera; various high resolution, light intensified and thermal video cameras; and several experimental sensors (e.g. the Portable Hyperspectral Imager of Low-Light Spectroscopy (PHILLS)). Over the past year or so, the Coastal Marine Resource Assessment (CAMRA) group at the Florida Department of Environmental Protection`s Marine Research Institute (FMRI) has been working with the Department of Energy through the Naval Research Laboratory to develop applications and products from existing data. Considerable effort has been spent identifying image formats integration parameters. 2 refs., 3 figs., 2 tabs.

  7. The Goldstone Solar System Radar: 1988-2003 Earth-based Mars Radar Observations

    NASA Technical Reports Server (NTRS)

    Haldemann, A. F. C.; Jurgens, R. F.; Slade, M. A.; Larsen, K. W.

    2005-01-01

    The Goldstone Solar System Radar (GSSR) has successfully collected radar echo data from Mars over the past 30 years. The older data provided local elevation information for Mars, along with radar scattering information with global resolution. Since the upgrade to the 70-m DSN antenna at Goldstone completed in 1986, Mars data has been collected during all but the 1997 Mars opposition. Radar data, and non-imaging delay- Doppler data in particular, requires significant data processing to extract elevation, reflectivity and roughness of the reflecting surface. The spatial resolution of these experiments is typically some 10 km in longitude by some 150 km in latitude. The interpretation of these parameters while limited by the complexities of electromagnetic scattering, do provide information directly relevant to geophysical and geomorphic analyses of Mars.

  8. Echo Source Discrimination in Airborne Radar Sounding Data for Mars Analog Studies, Dry Valleys, Antarctica

    NASA Technical Reports Server (NTRS)

    Holt, J. W.; Blankenship, D. D.; Peters, M. E.; Kempf, S. D.; Morse, D. L.; Williams, B. J.

    2003-01-01

    The recent identification of features on Mars exhibiting morphologies consistent with ice/rock mixtures, near-surface ice bodies and near-surface liquid water [1,2], and the importance of such features to the search for water on Mars, highlights the need for appropriate terrestrial analogs in order to prepare for upcoming radar missions targeting these and other water-related features. Climatic, hydrological, and geological conditions in the McMurdo Dry Valleys of Antarctica are analogous in many ways to those on Mars, and a number of ice-related features in the Dry Valleys may have direct morphologic and compositional counterparts on Mars.

  9. 29. Perimeter acquisition radar building room #318, data processing system ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. Perimeter acquisition radar building room #318, data processing system area; data processor maintenance and operations center, showing data processing consoles - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

  10. Radome effects on coherent change detection radar systems

    NASA Astrophysics Data System (ADS)

    Raynal, Ann Marie; Dubbert, Dale F.; Burns, Bryan L.; Hensley, William H.

    2015-05-01

    A radome, or radar dome, protects a radar system from exposure to the elements. Unfortunately, radomes can affect the radiation pattern of the enclosed antenna. The co-design of a platform's radome and radar is ideal to mitigate any deleterious effects of the radome. However, maintaining structural integrity and other platform flight requirements, particularly when integrating a new radar onto an existing platform, often limits radome electrical design choices. Radars that rely heavily on phase measurements such as monopulse, interferometric, or coherent change detection (CCD) systems require particular attention be paid to components, such as the radome, that might introduce loss and phase variations as a function of the antenna scan angle. Material properties, radome wall construction, overall dimensions, and shape characteristics of a radome can impact insertion loss and phase delay, antenna beamwidth and sidelobe level, polarization, and ultimately the impulse response of the radar, among other things, over the desired radar operating parameters. The precision-guided munitions literature has analyzed radome effects on monopulse systems for well over half a century. However, to the best of our knowledge, radome-induced errors on CCD performance have not been described. The impact of radome material and wall construction, shape, dimensions, and antenna characteristics on CCD is examined herein for select radar and radome examples using electromagnetic simulations.

  11. Shuttle Imaging Radar-C mission operations - Technology test bed for Earth Observing System synthetic aperture radar

    NASA Technical Reports Server (NTRS)

    Trimble, J. P.; Collins, C. E.

    1992-01-01

    The mission operations for the Space Radar Lab (SRL), particularly in the areas of real-time replanning and science activity coordination, are presented. The two main components of SRL are the Shuttle Imaging Radar-C and the X-Band Synthetic Aperture Radar. The Earth Observing System SAR will be a multispectral, multipolarization radar satellite that will provide information over an entire decade, permitting scientists to monitor large-scale changes in the earth's environment over a long period of time.

  12. Laser radar system for obstacle avoidance

    NASA Astrophysics Data System (ADS)

    Bers, Karlheinz; Schulz, Karl R.; Armbruster, Walter

    2005-09-01

    The threat of hostile surveillance and weapon systems require military aircraft to fly under extreme conditions such as low altitude, high speed, poor visibility and incomplete terrain information. The probability of collision with natural and man-made obstacles during such contour missions is high if detection capability is restricted to conventional vision aids. Forward-looking scanning laser radars which are build by the EADS company and presently being flight tested and evaluated at German proving grounds, provide a possible solution, having a large field of view, high angular and range resolution, a high pulse repetition rate, and sufficient pulse energy to register returns from objects at distances of military relevance with a high hit-and-detect probability. The development of advanced 3d-scene analysis algorithms had increased the recognition probability and reduced the false alarm rate by using more readily recognizable objects such as terrain, poles, pylons, trees, etc. to generate a parametric description of the terrain surface as well as the class, position, orientation, size and shape of all objects in the scene. The sensor system and the implemented algorithms can be used for other applications such as terrain following, autonomous obstacle avoidance, and automatic target recognition. This paper describes different 3D-imaging ladar sensors with unique system architecture but different components matched for different military application. Emphasis is laid on an obstacle warning system with a high probability of detection of thin wires, the real time processing of the measured range image data, obstacle classification und visualization.

  13. Millimeter wave radar for automobile crash avoidance systems

    NASA Astrophysics Data System (ADS)

    Huguenin, G. Richard

    1994-08-01

    Low cost, millimeter wave, forward looking radar sensors for applications in Autonomous Collision Warning and Autonomous Intelligent Cruise Control systems will be described. These safety related systems promise the largest payoff in preventing highway crashes.

  14. The Sensitivity of a Volcanic Flow Model to Digital Elevation Models From Diverse Sources: Digitized Map Contours and Airborne Interferometric Radar

    NASA Astrophysics Data System (ADS)

    Stevens, N. F.; Manville, V.; Heron, D. W.

    2001-12-01

    A growing trend in the field of volcanic hazard assessment is the use of computer models of a variety of flows to predict potential areas of devastation. The accuracy of these computer models depends on two factors, the nature and veracity of the flow model itself, and the accuracy of the topographic data set over which it is run. All digital elevation models (DEMs) contain innate errors. The nature of these depends on the accuracy of the original measurements of the terrain, and on the method used to build the DEM. We investigate the effect that these errors have on the performance of a simple volcanic flow model designed to delineate areas at risk from lahar inundation. The volcanic flow model was run over two DEMs of southern Ruapehu volcano derived from (1) digitized 1:50,000 topographic maps, and (2) airborne C-band synthetic aperture radar interferometry obtained using the NASA AIRSAR system. On steep slopes (exceeding 4 degrees), drainage channels are more likely to be incised deeply, and flow paths predicted by the model are generally in agreement for both DEMs despite the differing nature of the source data. Over shallow slopes (approx. 4 degrees and less), where channels are less deep and are more likely to meander, problems were encountered with flow path prediction in both DEMs due to interpolation errors and forestry. The predicted lateral and longitudinal extent of deposit inundation was also sensitive to the type of DEM used, most likely in response to the differing degrees of surface texture preserved in the DEMs. A technique to refine contour-derived DEMs and reduce the error in predicted flow paths was tested to improve the reliability of the modeled flow path predictions. The suitability of forthcoming topographic measurements acquired by a single-pass space-borne instrument, the NASA Shuttle Radar Topography Mission (SRTM) are also tested.

  15. The 3D laser radar vision processor system

    NASA Technical Reports Server (NTRS)

    Sebok, T. M.

    1990-01-01

    Loral Defense Systems (LDS) developed a 3D Laser Radar Vision Processor system capable of detecting, classifying, and identifying small mobile targets as well as larger fixed targets using three dimensional laser radar imagery for use with a robotic type system. This processor system is designed to interface with the NASA Johnson Space Center in-house Extra Vehicular Activity (EVA) Retriever robot program and provide to it needed information so it can fetch and grasp targets in a space-type scenario.

  16. Radar Observations of Convective Systems from a High-Altitude Aircraft

    NASA Technical Reports Server (NTRS)

    Heymsfield, G.; Geerts, B.; Tian, L.

    1999-01-01

    Reflectivity data collected by the precipitation radar on board the tropical Rainfall Measuring Mission (TRMM) satellite, orbiting at 350 km altitude, are compared to reflectivity data collected nearly simultaneously by a doppler radar aboard the NASA ER-2 flying at 19-20 km altitude, i.e. above even the deepest convection. The TRMM precipitation radar is a scanning device with a ground swath width of 215 km, and has a resolution of about a4.4 km in the horizontal and 250 m in the vertical (125 m in the core swath 48 km wide). The TRMM radar has a wavelength of 217 cm (13.8 GHz) and the Nadir mirror echo below the surface is used to correct reflectivity for loss by attenuation. The ER-2 Doppler radar (EDOP) has two antennas, one pointing to the nadir, 34 degrees forward. The forward pointing beam receives both the normal and the cross-polarized echos, so the linear polarization ratio field can be monitored. EDOP has a wavelength of 3.12 cm (9.6 GHz), a vertical resolution of 37.5 m and a horizontal along-track resolution of about 100 m. The 2-D along track airflow field can be synthesized from the radial velocities of both beams, if a reflectivity-based hydrometer fall speed relation can be assumed. It is primarily the superb vertical resolution that distinguishes EDOP from other ground-based or airborne radars. Two experiments were conducted during 1998 into validate TRMM reflectivity data over convection and convectively-generated stratiform precipitation regions. The Teflun-A (TEXAS-Florida Underflight) experiment, was conducted in April and May and focused on mesoscale convective systems mainly in southeast Texas. TEFLUN-B was conducted in August-September in central Florida, in coordination with CAMEX-3 (Convection and Moisture Experiment). The latter was focused on hurricanes, especially during landfall, whereas TEFLUN-B concentrated on central; Florida convection, which is largely driven and organized by surface heating and ensuing sea breeze circulations

  17. Data System for HS3 Airborne Field Campaign

    NASA Astrophysics Data System (ADS)

    Maskey, M.; Mceniry, M.; Berendes, T.; Bugbee, K.; Conover, H.; Ramachandran, R.

    2014-12-01

    Hurricane and Severe Storm Sentinel (HS3) is a NASA airborne field campaign aimed at better understanding the physical processes that control hurricane intensity change. HS3 will help answer questions related to the roles of environmental conditions and internal storm structures to storm intensification. Due to the nature of the questions that HS3 mission is addressing, it involves a variety of in-situ, satellite observations, airborne data, meteorological analyses, and simulation data. This variety of datasets presents numerous data management challenges for HS3. The methods used for airborne data management differ greatly from the methods used for space-borne data. In particular, metadata extraction, spatial and temporal indexing, and the large number of instruments and subsequent variables are a few of the data management challenges unique to airborne missions. A robust data system is required to successfully help HS3 scientist achieve their mission goals. Furthermore, the data system also needs to provide for data management that assists in broader use of HS3 data to enable future research activities. The Global Hydrology Resource Center (GHRC) is considering all these needs and designing a data system for HS3. Experience with past airborne field campaign puts GHRC in a good position to address HS3 needs. However, the scale of this mission along with science requirements separates HS3 from previous field campaigns. The HS3 data system will include automated services for geo-location, metadata extraction, discovery, and distribution for all HS3 data. To answer the science questions, the data system will include a visual data exploration tool that is fully integrated into the data catalog. The tool will allow visually augmenting airborne data with analyses and simulations. Satellite data will provide contextual information during such data explorations. All HS3 tools will be supported by an enterprise service architecture that will allow scaling, easy integration

  18. Airborne Electro-Optical Sensor Simulation System. Final Report.

    ERIC Educational Resources Information Center

    Hayworth, Don

    The total system capability, including all the special purpose and general purpose hardware comprising the Airborne Electro-Optical Sensor Simulation (AEOSS) System, is described. The functional relationship between hardware portions is described together with interface to the software portion of the computer image generation. Supporting rationale…

  19. Synthetic aperture radar capabilities in development

    SciTech Connect

    Miller, M.

    1994-11-15

    The Imaging and Detection Program (IDP) within the Laser Program is currently developing an X-band Synthetic Aperture Radar (SAR) to support the Joint US/UK Radar Ocean Imaging Program. The radar system will be mounted in the program`s Airborne Experimental Test-Bed (AETB), where the initial mission is to image ocean surfaces and better understand the physics of low grazing angle backscatter. The Synthetic Aperture Radar presentation will discuss its overall functionality and a brief discussion on the AETB`s capabilities. Vital subsystems including radar, computer, navigation, antenna stabilization, and SAR focusing algorithms will be examined in more detail.

  20. Hardware system concept For student's space synthetic aperture radar (ESA SSETI-ESMO project)

    NASA Astrophysics Data System (ADS)

    Dawidowicz, Bartek; Filipek, Tomasz; Piotrkowski, Michał

    2006-02-01

    In this paper a concept of a cheap, lightweight, low power satellite radar for Moon's surface mapping is presented. This radar is designed to work in two modes: two-dimensional imaging (Synthetic Aperture Radar - SAR) and three-dimensional imaging (Interferometric Synthetic Aperture Radar - IfSAR). The proposed radar system performs the functions both of a radar system and a high data rate communication system. This enables costs and weight reduction which is very important in space applications.

  1. Formal methods and digital systems validation for airborne systems

    NASA Technical Reports Server (NTRS)

    Rushby, John

    1993-01-01

    This report has been prepared to supplement a forthcoming chapter on formal methods in the FAA Digital Systems Validation Handbook. Its purpose is as follows: to outline the technical basis for formal methods in computer science; to explain the use of formal methods in the specification and verification of software and hardware requirements, designs, and implementations; to identify the benefits, weaknesses, and difficulties in applying these methods to digital systems used on board aircraft; and to suggest factors for consideration when formal methods are offered in support of certification. These latter factors assume the context for software development and assurance described in RTCA document DO-178B, 'Software Considerations in Airborne Systems and Equipment Certification,' Dec. 1992.

  2. CloudSat as a Global Radar Calibrator

    SciTech Connect

    Protat, Alain; Bouniol, Dominique; O'Connor, E. J.; Baltink, Henk K.; Verlinde, J.; Widener, Kevin B.

    2011-03-01

    The calibration of the CloudSat spaceborne cloud radar has been thoroughly assessed using very accurate internal link budgets before launch, comparisons with predicted ocean surface backscatter at 94 GHz, direct comparisons with airborne cloud radars, and statistical comparisons with ground-based cloud radars at different locations of the world. It is believed that the calibration of CloudSat is accurate to within 0.5 to 1 dB. In the present paper it is shown that an approach similar to that used for the statistical comparisons with ground-based radars can now be adopted the other way around to calibrate other ground-based or airborne radars against CloudSat and / or detect anomalies in long time series of ground-based radar measurements, provided that the calibration of CloudSat is followed up closely (which is the case). The power of using CloudSat as a Global Radar Calibrator is demonstrated using the Atmospheric Radiation Measurement cloud radar data taken at Barrow, Alaska, the cloud radar data from the Cabauw site, The Netherlands, and airborne Doppler cloud radar measurements taken along the CloudSat track in the Arctic by the RASTA (Radar SysTem Airborne) cloud radar installed in the French ATR-42 aircraft for the first time. It is found that the Barrow radar data in 2008 are calibrated too high by 9.8 dB, while the Cabauw radar data in 2008 are calibrated too low by 8.0 dB. The calibration of the RASTA airborne cloud radar using direct comparisons with CloudSat agrees well with the expected gains and losses due to the change in configuration which required verification of the RASTA calibration.

  3. Quantification of Shear-Relative Asymmetries in Eyewall Slope Using Airborne Doppler Radar Composites

    NASA Astrophysics Data System (ADS)

    Hazelton, A.; Rogers, R.; Hart, R. E.

    2013-12-01

    Recently, it has become apparent that typical methods for analyzing tropical cyclones (TCs), such as track and intensity, are insufficient for evaluating TC structural evolution and numerical model forecasts of that evolution. Many studies have analyzed different metrics related to TC inner-core structure in an attempt to better understand the processes that drive changes in core structure. One important metric related to vertical TC structure is the slope of the eyewall. Hazelton and Hart (2013) discussed azimuthal mean eyewall slope based on radar reflectivity data, and its relationship with TC intensity and core structure. That study also noted significant azimuthal variation in slopes, but did not significantly explore reasons for this variation. Accordingly, in this study, we attempt to quantify the role of vertical wind shear in causing azimuthal variance of slope, using research quality Doppler radar composites from the NOAA Hurricane Research Division (HRD). We analyze the slope of the 20 dBZ surface as in Hazelton and Hart (2013), and also look at azimuthal variation in other measures of eyewall slope, such as the slope of the radius of maximum winds (RMW), which has been analyzed in an azimuthal mean sense by Stern and Nolan (2009), and an angular momentum surface. The shear-relative slopes are quantified by separating the radar data into four quadrants relative to the vertical shear vector: Downshear Left (DSL), Upshear Left (USL), Upshear Right (USR), and Downshear Right (DSR). This follows the method employed in shear-relative analyses of other aspects of TC core structure, such as Rogers et al. (2013) and Reasor et al. (2013). The data suitable for use in this study consist of 36 flights into 15 different TCs (14 Atlantic, 1 Eastern Pacific) between 1997 and 2010. Preliminary results show apparent shear-induced asymmetries in eyewall slope. The slope of the RMW shows an asymmetry due to the tilt of the vortex approximately along the shear vector, with

  4. Quantifying monthly to decadal subsidence and assessing collapse potential near the Wink sinkholes, west Texas, using airborne lidar, radar interferometry, and microgravity

    NASA Astrophysics Data System (ADS)

    Paine, J. G.; Collins, E.; Yang, D.; Andrews, J. R.; Averett, A.; Caudle, T.; Saylam, K.

    2014-12-01

    We are using airborne lidar and satellite-based radar interferometry (InSAR) to quantify short-term (months to years) and longer-term (decades) subsidence in the area surrounding two large (100- to 200-m diameter) sinkholes that formed above Permian bedded salt in 1980 and 2002 in the Wink area, west Texas. Radar interferograms constructed from synthetic aperture radar data acquired between 2008 and 2011 with the ALOS PALSAR L-band satellite-borne instrument reveal local areas that are subsiding at rates that reach a few cm per month. Subsiding areas identified on radar interferograms enable labor-intensive ground investigations (such as microgravity surveys) to focus on areas where subsidence is occurring and shallow-source mass deficits might exist that could be sites of future subsidence or collapse. Longer-term elevation changes are being quantified by comparing digital elevation models (DEMs) constructed from high-resolution airborne lidar data acquired over a 32-km2 area in 2013 with older, lower-resolution DEMs constructed from data acquired during the NASA- and NGA-sponsored Shuttle Radar Topographic Mission in February 2000 and from USGS aerial photogrammetry-derived topographic data from the 1960s. Total subsidence reaches more than 10 m over 45 years in some areas. Maximum rates of subsidence measured on annual (from InSAR) and decadal (from lidar) time scales are about 0.25 m/yr. In addition to showing the extent and magnitude of subsidence at the 1980 and 2002 sinkholes, comparison of the 2013 lidar-derived DEM with the 1960s photogrammetry-derived DEM revealed other locations that have undergone significant (more than 1 m) elevation change since the 1960s, but show no evidence of recent (2008 to 2011) ground motion from satellite radar interferograms. Regional coverage obtained by radar interferometry and local coverage obtained with airborne lidar show that areas of measurable subsidence are all within a few km of the 1980 and 2002 sinkholes.

  5. Airborne synthetic aperture radar observations and simulations for waves in ice

    NASA Technical Reports Server (NTRS)

    Vachon, Paris W.; Olsen, Richard B.; Krogstad, Harald E.; Liu, Antony K.

    1993-01-01

    The Canada Centre for Remote Sensing CV-580 aircraft collected C-band SAR data over the marginal ice zone off the east coast of Newfoundland during the Labrador Ice Margin Experiment (LIMEX) in March 1989. One component of the LIMEX '89 program was the study of ocean waves penetrating the marginal ice zone. We consider nearly coincidental observations of waves in ice by airborne SAR and wave-induced ice motion measurements. We explain the wave patterns observed in the SAR imagery, and the corresponding SAR image spectra, in terms of SAR wave imaging models. These include the well-known tilt cross-section modulation, linear, quasi-linear, and nonlinear velocity bunching forward mapping models (FMMs), and the assertion that the concept of coherence time limitation applies differently to the cases of waves in ice and open water. We modify the concept of the scene coherence time to include two parts: first, a decorrelation time deduced from the inherent azimuth cutoff in the nonlinear velocity bunching FMM; and second, the intrinsic scene coherence time which is a measure of the time scale over which an open water Bragg scattering patch retains its phase structure. Either of these coherence time scales could dominate the SAR image formation process, depending upon the environmental conditions (the wave spectrum and the wind speed, for example). Observed SAR image spectra and forward mapped ice motion package spectra are favorably compared.

  6. Integrated mobile radar-camera system in airport perimeter security

    NASA Astrophysics Data System (ADS)

    Zyczkowski, M.; Szustakowski, M.; Ciurapinski, W.; Dulski, R.; Kastek, M.; Trzaskawka, P.

    2011-11-01

    The paper presents the test results of a mobile system for the protection of large-area objects, which consists of a radar and thermal and visual cameras. Radar is used for early detection and localization of an intruder and the cameras with narrow field of view are used for identification and tracking of a moving object. The range evaluation of an integrated system are presented as well as the probability of human detection as a function of the distance from radar-camera unit.

  7. Integrated radar-camera security system: range test

    NASA Astrophysics Data System (ADS)

    Zyczkowski, M.; Szustakowski, M.; Ciurapinski, W.; Karol, M.; Markowski, P.

    2012-06-01

    The paper presents the test results of a mobile system for the protection of large-area objects, which consists of a radar and thermal and visual cameras. Radar is used for early detection and localization of an intruder and the cameras with narrow field of view are used for identification and tracking of a moving object. The range evaluation of an integrated system is presented as well as the probability of human detection as a function of the distance from radar-camera unit.

  8. Signal Processing System for the CASA Integrated Project I Radars

    SciTech Connect

    Bharadwaj, Nitin; Chandrasekar, V.; Junyent, Francesc

    2010-09-01

    This paper describes the waveform design space and signal processing system for dual-polarization Doppler weather radar operating at X band. The performance of the waveforms is presented with ground clutter suppression capability and mitigation of range velocity ambiguity. The operational waveform is designed based on operational requirements and system/hardware requirements. A dual Pulse Repetition Frequency (PRF) waveform was developed and implemented for the first generation X-band radars deployed by the Center for Collaborative Adaptive Sensing of the Atmosphere (CASA). This paper presents an evaluation of the performance of the waveforms based on simulations and data collected by the first-generation CASA radars during operations.

  9. Estimation of lava flow field volumes and volumetric effusion rates from airborne radar profiling and other data: Monitoring of the Nornahraun (Holuhraun) 2014/15 eruption in Iceland

    NASA Astrophysics Data System (ADS)

    Dürig, Tobias; Gudmundsson, Magnús; Högnadóttir, Thordís; Jónsdóttir, Ingibjörg; Gudbjörnsson, Snaebjörn; Lárusson, Örnólfur; Höskuldsson, Ármann; Thordarson, Thorvaldur; Riishuus, Morten; Magnússon, Eyjólfur

    2015-04-01

    Monitoring of lava-producing eruptions involves systematic measurement of flow field volumes, which in turn can be used to obtain average magma discharge over the period of observation. However, given inaccessibility to the interior parts of active lava fields, remote sensing techniques must be applied. Several satellite platforms provide data that can be geo-referenced, allowing area estimation. However, unless sterographic or tandem satellite data are available, the determination of thicknesses is non-trivial. The ongoing eruption ('Nornaeldar')at Dyngjusandurin the Icelandic highlands offers an opportunity to monitor the temporal and spatial evolution of a typical Icelandic lava flow field. The mode of emplacementis complex and includesboth horizontal and vertical stacking, inflation of lobes and topographic inversions. Due to the large extent of the flow field (>83 km2 on 5 Jan 2015, and still growing) and its considerable local variation in thickness (30 m) and surface roughness, obtaining robust quantification of lava thicknesses is very challenging,despite the lava is being emplaced onto a low-relief sandur plain. Creative methods have been implemented to obtain as reliable observation as possible into the third dimension: Next to areal extent measurements from satellites and maps generated with airborne synthetic-aperture radar (SAR), lava thickness profiles are regularly obtained by low-level flights with a fixed-wing aircraft that is equipped with a ground clearance radar coupled witha submeter DGPS,a system originally designed for monitoring surface changes of glaciers above geothermally active areas.The resulting radar profile data are supplemented by analyses of aerial photos and complemented by results from an array of ground based thickness measurement methods. The initial results indicate that average effusion ratewas ~200 m3/s in the first weeks of the eruption (end August, early September) but declined to 50-100 m3/s in November to December period

  10. Antarctic Firn Compaction Rates from Repeat-Track Airborne Radar Data: I. Methods

    NASA Technical Reports Server (NTRS)

    Medley, B.; Ligtenberg, S. R. M.; Joughin, I.; Van Den Broeke, M. R.; Gogineni, S.; Nowicki, S.

    2015-01-01

    While measurements of ice-sheet surface elevation change are increasingly used to assess mass change, the processes that control the elevation fluctuations not related to ice-flow dynamics (e.g. firn compaction and accumulation) remain difficult to measure. Here we use radar data from the Thwaites Glacier (West Antarctica) catchment to measure the rate of thickness change between horizons of constant age over different time intervals: 2009-10, 2010-11 and 2009-11. The average compaction rate to approximately 25m depth is 0.33ma(exp -1), with largest compaction rates near the surface. Our measurements indicate that the accumulation rate controls much of the spatio-temporal variations in the compaction rate while the role of temperature is unclear due to a lack of measurements. Based on a semi-empirical, steady-state densification model, we find that surveying older firn horizons minimizes the potential bias resulting from the variable depth of the constant age horizon. Our results suggest that the spatiotemporal variations in the firn compaction rate are an important consideration when converting surface elevation change to ice mass change. Compaction rates varied by up to 0.12ma(exp -1) over distances less than 6km and were on average greater than 20% larger during the 2010-11 interval than during 2009-10.

  11. The EISCAT Svalbard radar: A case study in modern incoherent scatter radar system design

    NASA Astrophysics Data System (ADS)

    Wannberg, G.; Wolf, I.; Vanhainen, L.-G.; Koskenniemi, K.; RöTtger, J.; Postila, M.; Markkanen, J.; Jacobsen, R.; Stenberg, A.; Larsen, R.; Eliassen, S.; Heck, S.; Huuskonen, A.

    1997-11-01

    The EISCAT (European incoherent scatter) Svalbard radar (ESR) was officially inaugurated on August 22, 1996. This event marked the successful completion on schedule of the first phase of the EISCAT Svalbard radar project. In contrast to previous incoherent scatter radars, the ESR system design was adapted to make use of commercial off-the-shelf TV transmitter hardware, thereby reducing design risk, lead times, and cost to a minimum. Commercial hardware is also used in the digital signal processing system. Control and monitoring are performed by distributed, networked VME systems. Thanks to modern reflector antenna design methods and extreme efforts to reduce the receiver noise contribution, the system noise temperature is only 70 K, thus making the ESR about 30% faster than the much more powerful EISCAT UHF radar in F region experiments! Once the transmitter power is increased to 1 MW, it will become about 2-3 times faster than the UHF radar. State-of-the-art exciter and receiver hardware has been developed in-house to accommodate the special requirements introduced by operating the radar at the exceptionally high duty cycle of 25%. The RF waveform is generated by a system based on four switchable direct digital synthesizers. Continuous monitoring of the transmitted RF waveform by the receiver system allows removal of klystron-induced spurious Doppler effects from the data. Intermediate-frequency sampling at 7.5 MHz is employed, followed by fully digital channel separation, signal detection, and postdetection filtering in six parallel receiver channels. Radar codes for both E and F layer observation have been designed and perfected. So far, more than 40 hours of good quality ionospheric data have been collected and analyzed in terms of plasma parameters. While the tragic loss of the Cluster mission suddenly changed the plans and dispositions of a majority of the ESR user community, the radar has still been in high demand since its inauguration. It is now being

  12. Low cost airborne microwave landing system receiver, task 3

    NASA Technical Reports Server (NTRS)

    Hager, J. B.; Vancleave, J. R.

    1979-01-01

    Work performed on the low cost airborne Microwave Landing System (MLS) receiver is summarized. A detailed description of the prototype low cost MLS receiver is presented. This detail includes block diagrams, schematics, board assembly drawings, photographs of subassemblies, mechanical construction, parts lists, and microprocessor software. Test procedures are described and results are presented.

  13. Assess program: Interactive data management systems for airborne research

    NASA Technical Reports Server (NTRS)

    Munoz, R. M.; Reller, J. O., Jr.

    1974-01-01

    Two data systems were developed for use in airborne research. Both have distributed intelligence and are programmed for interactive support among computers and with human operators. The C-141 system (ADAMS) performs flight planning and telescope control functions in addition to its primary role of data acquisition; the CV-990 system (ADDAS) performs data management functions in support of many research experiments operating concurrently. Each system is arranged for maximum reliability in the first priority function, precision data acquisition.

  14. MAJOR SOURCE OF SIDE-LOOKING AIRBORNE RADAR IMAGERY FOR RESEARCH AND EXPLORATION: THE U. S. GEOLOGICAL SURVEY.

    USGS Publications Warehouse

    Kover, Allan N.; Jones, John Edwin; ,

    1985-01-01

    The US Geological Survey (USGS) instituted a program in 1980 to acquire side-looking airbore radar (SLAR) data and make these data readily available to the public in a mosaic format comparable to the USGS 1:250,000-scale topographic map series. The SLAR data are also available as strip images at an acquisition scale of 1:250,000 or 1:400,000 (depending on the acquisition system), as a variety of print products and indexes, and in a limited amount in digital form on computer compatible tapes. Three different commercial X-band (3-cm) systems were used to acquire the imagery for producing the mosaics.

  15. Marsh dieback, loss, and recovery mapped with satellite optical, airborne polarimetric radar, and field data

    USGS Publications Warehouse

    Ramsey, Elijah W.; Rangoonwala, Amina; Chi, Zhaohui; Jones, Cathleen E.; Bannister, Terri

    2014-01-01

    Landsat Thematic Mapper and Satellite Pour l'Observation de la Terre (SPOT) satellite based optical sensors, NASA Uninhabited Aerial Vehicle synthetic aperture radar (UAVSAR) polarimetric SAR (PolSAR), and field data captured the occurrence and the recovery of an undetected dieback that occurred between the summers of 2010, 2011, and 2012 in the Spartina alterniflora marshes of coastal Louisiana. Field measurements recorded the dramatic biomass decrease from 2010 to 2011 and a biomass recovery in 2012 dominated by a decrease of live biomass, and the loss of marsh as part of the dieback event. Based on an established relationship, the near-infrared/red vegetation index (VI) and site-specific measurements delineated a contiguous expanse of marsh dieback encompassing 6649.9 ha of 18,292.3 ha of S. alterniflora marshes within the study region. PolSAR data were transformed to variables used in biophysical mapping, and of this variable suite, the cross-polarization HV (horizontal send and vertical receive) backscatter was the best single indicator of marsh dieback and recovery. HV backscatter exhibited substantial and significant changes over the dieback and recovery period, tracked measured biomass changes, and significantly correlated with the live/dead biomass ratio. Within the context of regional trends, both HV and VI indicators started higher in pre-dieback marshes and exhibited substantially and statistically higher variability from year to year than that exhibited in the non-dieback marshes. That distinct difference allowed the capturing of the S. alterniflora marsh dieback and recovery; however, these changes were incorporated in a regional trend exhibiting similar but more subtle biomass composition changes.

  16. A 10 cm dual frequency Doppler weather radar. Part 1: The radar system

    NASA Astrophysics Data System (ADS)

    Bishop, A. W.; Armstrong, G. M.

    1982-10-01

    Design concepts and test results are summarized for a Doppler weather radar system suitable for precipitation measurements over a wide span of radial velocities and slant ranges, even in the presence of ground clutter. The radar transmits two uniform pulse trains at 2.710 and 2.760 GHz. Uniformly spaced pulses permit ground clutter cancellation of up to 50 dB to be achieved with a three-pole elliptic filter. Pulse spacing at one frequency is consistent with long-range coverage in reflectivity, while spacing of the second is consistent with a wide unambiguous velocity measurement span.

  17. Radar systems for the water resources mission, volume 2

    NASA Technical Reports Server (NTRS)

    Moore, R. K.; Claassen, J. P.; Erickson, R. L.; Fong, R. K. T.; Hanson, B. C.; Komen, M. J.; Mcmillan, S. B.; Parashar, S. K.

    1976-01-01

    The application of synthetic aperture radar (SAR) in monitoring and managing earth resources was examined. The function of spaceborne radar is to provide maps and map imagery to be used for earth resource and oceanographic applications. Spaceborne radar has the capability of mapping the entire United States regardless of inclement weather; however, the imagery must have a high degree of resolution to be meaningful. Attaining this resolution is possible with the SAR system. Imagery of the required quality must first meet mission parameters in the following areas: antenna patterns, azimuth and range ambiguities, coverage, and angle of incidence.

  18. Micropower radar systems for law enforcement technology

    SciTech Connect

    Azevedo, S.G.; Mast, J.; Brase, J.

    1994-11-15

    LLNL researchers have pioneered a unique compact low-power and inexpensive radar technology (microradar) that has enormous potential in various industries. Some licenses are currently in place for motion sensors and stud finders. The ultra-wideband characteristics of the microradar (4 to 10 GHz) make it difficult to detect, yet provide potential range resolution of 1 cm at ranges of greater than 20 meters. Real and synthetic apertures arrays of radar elements can address imaging applications behind walls at those distances. Personnel detection applications are currently being tested.

  19. A system model and inversion for synthetic aperture radar imaging.

    PubMed

    Soumekh, M

    1992-01-01

    A system model and its corresponding inversion for synthetic aperture radar (SAR) imaging are presented. The system model incorporates the spherical nature of a radar's radiation pattern at far field. The inverse method based on this model performs a spatial Fourier transform (Doppler processing) on the recorded signals with respect to the available coordinates of a translational radar (SAR) or target (inverse SAR). It is shown that the transformed data provide samples of the spatial Fourier transform of the target's reflectivity function. The inverse method can be modified to incorporate deviations of the radar's motion from its prescribed straight line path. The effects of finite aperture on resolution, reconstruction, and sampling constraints for the imaging problem are discussed.

  20. A Potential Integrated Multiwavelength Radar System at the Medicina Radiotelescopes

    NASA Astrophysics Data System (ADS)

    Montebugnoli, S.; Salerno, E.; Pupillo, G.; Pluchino, S.

    2009-03-01

    Ground-based radars provide a powerful tool for detection, tracking and identification of the space debris fragments orbiting around Earth at different altitudes. The Medicina Radioastronomical Station is an Italian radio observation facility that is here proposed as receiving part of a bistatic radar system for detecting and tracking space debris at different orbital regions (from Low Earth Orbits up to Geostationary Earth Orbits).

  1. Towards a Multi-Mission, Airborne Science Data System Environment

    NASA Astrophysics Data System (ADS)

    Crichton, D. J.; Hardman, S.; Law, E.; Freeborn, D.; Kay-Im, E.; Lau, G.; Oswald, J.

    2011-12-01

    NASA earth science instruments are increasingly relying on airborne missions. However, traditionally, there has been limited common infrastructure support available to principal investigators in the area of science data systems. As a result, each investigator has been required to develop their own computing infrastructures for the science data system. Typically there is little software reuse and many projects lack sufficient resources to provide a robust infrastructure to capture, process, distribute and archive the observations acquired from airborne flights. At NASA's Jet Propulsion Laboratory (JPL), we have been developing a multi-mission data system infrastructure for airborne instruments called the Airborne Cloud Computing Environment (ACCE). ACCE encompasses the end-to-end lifecycle covering planning, provisioning of data system capabilities, and support for scientific analysis in order to improve the quality, cost effectiveness, and capabilities to enable new scientific discovery and research in earth observation. This includes improving data system interoperability across each instrument. A principal characteristic is being able to provide an agile infrastructure that is architected to allow for a variety of configurations of the infrastructure from locally installed compute and storage services to provisioning those services via the "cloud" from cloud computer vendors such as Amazon.com. Investigators often have different needs that require a flexible configuration. The data system infrastructure is built on the Apache's Object Oriented Data Technology (OODT) suite of components which has been used for a number of spaceborne missions and provides a rich set of open source software components and services for constructing science processing and data management systems. In 2010, a partnership was formed between the ACCE team and the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) mission to support the data processing and data management needs

  2. Covariance analysis of the airborne laser ranging system

    NASA Technical Reports Server (NTRS)

    Englar, T. S., Jr.; Hammond, C. L.; Gibbs, B. P.

    1981-01-01

    The requirements and limitations of employing an airborne laser ranging system for detecting crustal shifts of the Earth within centimeters over a region of approximately 200 by 400 km are presented. The system consists of an aircraft which flies over a grid of ground deployed retroreflectors, making six passes over the grid at two different altitudes. The retroreflector baseline errors are assumed to result from measurement noise, a priori errors on the aircraft and retroreflector positions, tropospheric refraction, and sensor biases.

  3. Integration of WERA Ocean Radar into Tsunami Early Warning Systems

    NASA Astrophysics Data System (ADS)

    Dzvonkovskaya, Anna; Helzel, Thomas; Kniephoff, Matthias; Petersen, Leif; Weber, Bernd

    2016-04-01

    High-frequency (HF) ocean radars give a unique capability to deliver simultaneous wide area measurements of ocean surface current fields and sea state parameters far beyond the horizon. The WERA® ocean radar system is a shore-based remote sensing system to monitor ocean surface in near real-time and at all-weather conditions up to 300 km offshore. Tsunami induced surface currents cause increasing orbital velocities comparing to normal oceanographic situation and affect the measured radar spectra. The theoretical approach about tsunami influence on radar spectra showed that a tsunami wave train generates a specific unusual pattern in the HF radar spectra. While the tsunami wave is approaching the beach, the surface current pattern changes slightly in deep water and significantly in the shelf area as it was shown in theoretical considerations and later proved during the 2011 Japan tsunami. These observed tsunami signatures showed that the velocity of tsunami currents depended on a tsunami wave height and bathymetry. The HF ocean radar doesn't measure the approaching wave height of a tsunami; however, it can resolve the surface current velocity signature, which is generated when tsunami reaches the shelf edge. This strong change of the surface current can be detected by a phased-array WERA system in real-time; thus the WERA ocean radar is a valuable tool to support Tsunami Early Warning Systems (TEWS). Based on real tsunami measurements, requirements for the integration of ocean radar systems into TEWS are already defined. The requirements include a high range resolution, a narrow beam directivity of phased-array antennas and an accelerated data update mode to provide a possibility of offshore tsunami detection in real-time. The developed software package allows reconstructing an ocean surface current map of the area observed by HF radar based on the radar power spectrum processing. This fact gives an opportunity to issue an automated tsunami identification message

  4. Spaceborne Doppler Precipitation Radar: System Configurations and Performance Analysis

    NASA Technical Reports Server (NTRS)

    Tanelli, Simone; Im, Eastwood

    2004-01-01

    Knowledge of the global distribution of the vertical velocity of precipitation is important in in the study of energy transportation in the atmosphere, the climate and weather. Such knowledge can only be directly acquired with the use of spaceborne Doppler precipitation radars. Although the high relative speed of the radar with respect to the rainfall particles introduces significant broadening in the Doppler spectrum, recent studies have shown that the average vertical velocity can be measured to acceptable accuracy levels by appropriate selection of radar parameters. Furthermore, methods to correct for specific errors arising from NUBF effects and pointing uncertainties have recently been developed. In this paper we will present the results of the trade studies on the performances of a spaceborne Doppler radar with different system parameters configurations.

  5. An Integrated Data Acquisition / User Request/ Processing / Delivery System for Airborne Remote Sensing Data

    NASA Astrophysics Data System (ADS)

    Chapman, B.; Chu, A.; Tung, W.

    2003-12-01

    Airborne science data has historically played an important role in the development of the scientific underpinnings for spaceborne missions. When the science community determines the need for new types of spaceborne measurements, airborne campaigns are often crucial in risk mitigation for these future missions. However, full exploitation of the acquired data may be difficult due to its experimental and transitory nature. Externally to the project, most problematic (in particular, for those not involved in requesting the data acquisitions) may be the difficulty in searching for, requesting, and receiving the data, or even knowing the data exist. This can result in a rather small, insular community of users for these data sets. Internally, the difficulty for the project is in maintaining a robust processing and archival system during periods of changing mission priorities and evolving technologies. The NASA/JPL Airborne Synthetic Aperture Radar (AIRSAR) has acquired data for a large and varied community of scientists and engineers for 15 years. AIRSAR is presently supporting current NASA Earth Science Enterprise experiments, such as the Soil Moisture EXperiment (SMEX) and the Cold Land Processes experiment (CLPX), as well as experiments conducted as many as 10 years ago. During that time, it's processing, data ordering, and data delivery system has undergone evolutionary change as the cost and capability of resources has improved. AIRSAR now has a fully integrated data acquisition/user request/processing/delivery system through which most components of the data fulfillment process communicate via shared information within a database. The integration of these functions has reduced errors and increased throughput of processed data to customers.

  6. The NASA Airborne Science Data And Telemetry System (NASDAT)

    NASA Astrophysics Data System (ADS)

    Sorenson, C. E.; Forgione, J.; Barnes, C.

    2011-12-01

    A system providing a common core set of facility data services across the NASA Airborne Science Program research aircraft fleet is described. The NASA Airborne Science Data And Telemetry System (NASDAT) is a rugged avionics box that fits in a standard aeronautical radio rack mounting tray, and provides both aircraft and experimenter data interfaces. Ethernet, satcom, and legacy connections are supported. Standardized protocols allow this system to serve as an abstraction layer for interfacing any instrument to any aircraft. Built-in Iridium modems allow low rate baseline global data communications. Built on open standards and dynamically reconfigurable, the NASDAT enables any research platform to participate in the wider sensor web, such that remote experimenters can control their instruments, and display applications can receive near real time data. The production NASDAT was built this year, based in part on prototypes which have been flying on several research aircraft such as the NASA DC-8 and Global Hawk.

  7. Water depth measurement using an airborne pulsed neon laser system

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.; Frederick, E. B.

    1980-01-01

    The paper presents the water depth measurement using an airborne pulsed neon laser system. The results of initial base-line field test results of NASA airborne oceanographic lidar in the bathymetry mode are given, with water-truth measurements of depth and beam attenuation coefficients by boat taken at the same time as overflights to aid in determining the system's operational performance. The nadir-angle tests and field-of-view data are presented; this laser bathymetry system is an improvement over prior models in that (1) the surface-to-bottom pulse waveform is digitally recorded on magnetic tape, and (2) wide-swath mapping data may be routinely acquired using a 30 deg full-angle conical scanner.

  8. Ultrawideband imaging radar based on OFDM: system simulation analysis

    NASA Astrophysics Data System (ADS)

    Garmatyuk, Dmitriy

    2006-05-01

    Orthogonal frequency division-multiplexing (OFDM) is rapidly emerging as a preferred method of UWB signaling in commercial applications aimed mainly at low-power, high data-rate communications. This paper explores the possibility of applying OFDM to use in imaging radar technology. Ultra-wideband nature of the signal provides for high resolution of the radar, whereas usage of multi-sub-carrier method of modulation allows for dynamic spectrum allocation. Robust multi-path performance of OFDM signals and heavy reliance of transceiver design on digital processors easily implemented in modern VLSI technology make a number of possible applications viable, e.g.: portable high-resolution indoor radar/movement monitoring system; through-the-wall/foliage synthetic aperture imaging radar with a capability of image transmission/broadcasting, etc. Our work is aimed to provide a proof-of-concept simulation scenario to explore numerous aspects of UWB-OFDM radar imaging through evaluating range and cross-range imaging performance of such a system with an eventual goal of software-defined radio (SDR) implementation. Stripmap SAR topology was chosen for modeling purposes. Range/cross-range profiles were obtained along with full 2-D images for multi-target in noise scenarios. Model set-up and results of UWB-OFDM radar imaging simulation study using Matlab/Simulink modeling are presented and discussed in this paper.

  9. Scanning lidar with a coupled radar safety system.

    PubMed

    Kent, G S; Hansen, G M

    1999-10-20

    A small scanning three-wavelength lidar system at NASA Langley Research Center in Hampton, Virginia, has been used since 1992 to make atmospheric measurements on stratospheric and upper tropospheric aerosols and on the evolution of aircraft exhaust plumes. Many of these measurements have been made away from the zenith, and, to reduce the hazard to air traffic produced by the laser beam, a radar safety device has been installed. The radar application is original in that the radar beam is made collinear with the laser beam by use of a dichroic mirror that transmits the laser radiation and reflects the microwaves. This mirror is inserted into the outgoing optical path prior to the radiation from both the radar and the laser passing through the independent scanning unit. Tests of the complete system show that the lidar and radar beams remain collocated as they are scanned and that the radar can be used to inhibit the laser prior to an aircraft passing through the beam. PMID:18324168

  10. Radar imaging of solar system ices

    NASA Astrophysics Data System (ADS)

    Harcke, Leif J.

    We map the planet Mercury and Jupiter's moons Ganymede and Callisto using Earth-based radar telescopes and find that all of these have regions exhibiting high, depolarized radar backscatter and polarization inversion (m c > 1). Both characteristics suggest significant volume scattering from water ice or similar cold-trapped volatiles. Synthetic aperture radar mapping of Mercury's north and south polar regions at fine (6 km) resolution at 3.5 cm wavelength corroborates the results of previous 13 cm investigations of enhanced backscatter and polarization inversion (0.9 <= m c <= 1.3) from areas on the floors of craters at high latitudes, where Mercury's near-zero obliquity results in permanent Sun shadows. Co-registration with Mariner 10 optical images shows that this enhanced scattering cannot be caused by simple double-bounce geometries, since the bright, reflective regions do not appear on the radar-facing wall but, instead, in shadowed regions not directly aligned with the radar look direction. Thermal models require the existence of such a layer to preserve ice deposits in craters at other than high polar latitudes. The additional attenuation (factor 1.64 +/- 15%) of the 3.5 cm wavelength data from these experiments over previous 13 cm radar observations is consistent with a range of layer thickness from 0 +/- 11 to 35 +/- 15 cm, depending on the assumed scattering law exponent n. Our 3.5 cm wavelength bistatic aperture synthesis observations of the two outermost Galilean satellites of Jupiter, Ganymede and Callisto, resolve the north-south ambiguity of previous images, and confirm the disk-integrated enhanced backscatter and polarization inversion noted in prior investigations. The direct imaging technique more clearly shows that higher backscatter are as are associated with the terrain that has undergone recent resurfacing, such as the sulci and the impact crater basins. The leading hemispheres of both moons have somewhat higher (20% +/- 5%) depolarized echoes

  11. Progress reports for period November 1--30, 1994 -- Joint UK/US Radar Program

    SciTech Connect

    Twogood, R.E.; Brase, J.M.; Mantrom, D.D.; Chambers, D.H.; Robey, H.F.

    1994-12-19

    This report gives the principle investigator, objectives, recent accomplishments, milestones for reporting period, expected milestones for ensuing period, other issues and planned expenditures for the following programs: airborne RAR/SAR; radar data processor; ground-based SAR signal processing workstation; static airborne radar; multi-aperture space-time array radar; radar field experiments; data analysis and detection theory; management; E-2C radar data analysis;modeling and analysis; current meter array; UCSB wave tank; stratified flow facility; and IR sensor system. Budget status is also given.

  12. Progress reports for October 1994 -- Joint UK/US Radar Program

    SciTech Connect

    Twogood, R.E.; Brase, J.M.; Mantrom, D.D.; Chambers, D.H.; Robey, H.F.

    1994-11-18

    This report gives the principle investigator, objectives, recent accomplishments, milestones for reporting period, expected milestones for ensuing period, other issues and planned expenditures for each of the following programs: airborne RAR/SAR; radar data processor; ground-based SAR signal processing workstation; static airborne radar; multi-aperture space-time array radar; radar field experiments; data analysis and detection theory; management; E-2C radar data analysis; modeling and analysis; current meter array; UCSB wave tank; stratified flow facility; and IR sensor system. Finally the budget status is given.

  13. TELAER: a multi-mode/multi-antenna interferometric airborne SAR system

    NASA Astrophysics Data System (ADS)

    Perna, Stefano; Amaral, Tiago; Berardino, Paolo; Esposito, Carmen; Jackson, Giuseppe; Pauciullo, Antonio; Vaz Junior, Eurico; Wimmer, Christian; Lanari, Riccardo

    2014-05-01

    The present contribution is aimed at showing the capabilities of the TELAER airborne Synthetic Aperture Radar (SAR) system recently upgraded to the interferometric mode [1]. TELAER is an Italian airborne X-Band SAR system, mounted onboard a LearJet 35A aircraft. Originally equipped with a single TX/RX antenna, it now operates in single-pass interferometric mode thanks to a system upgrading [1] funded by the Italian National Research Council (CNR), via the Italian Ministry of Education, Universities and Research (MIUR), in the framework of a cooperation between CNR and the Italian Agency for Agriculture Subsidy Payments (AGEA). In the frame of such cooperation, CNR has entrusted the Institute for Electromagnetic Sensing of the Environment (IREA) for managing all the activities, included the final flight tests, related to the system upgrading. According to such an upgrading, two additional receiving X-band antennas have been installed in order to allow, simultaneously, single-pass Across-Track and Along-Track interferometry [1]. More specifically, the three antennas are now installed in such a way to produce three different across-track baselines and two different along-track baselines. Moreover, in the frame of the same system upgrading, it has been mounted onboard the Learjet an accurate embedded Global Navigation Satellite System and Inertial Measurement Unit equipment. This allows precise measurement of the tracks described by the SAR antennas during the flight, in order to accurately implement Motion Compensation (MOCO) algorithms [2] during the image formation (focusing) step. It is worth remarking that the TELAER system upgraded to the interferometric mode is very flexible, since the user can set different operational modes characterized by different geometric resolutions and range swaths. In particular, it is possible to reach up to 0.5 m of resolution with a range swath of 2km; conversely, it is possible to enlarge the range swath up to 10 km at expenses of

  14. Airborne change detection system for the detection of route mines

    NASA Astrophysics Data System (ADS)

    Donzelli, Thomas P.; Jackson, Larry; Yeshnik, Mark; Petty, Thomas E.

    2003-09-01

    The US Army is interested in technologies that will enable it to maintain the free flow of traffic along routes such as Main Supply Routes (MSRs). Mines emplaced in the road by enemy forces under cover of darkness represent a major threat to maintaining a rapid Operational Tempo (OPTEMPO) along such routes. One technique that shows promise for detecting enemy mining activity is Airborne Change Detection, which allows an operator to detect suspicious day-to-day changes in and around the road that may be indicative of enemy mining. This paper presents an Airborne Change Detection that is currently under development at the US Army Night Vision and Electronic Sensors Directorate (NVESD). The system has been tested using a longwave infrared (LWIR) sensor on a vertical take-off and landing unmanned aerial vehicle (VTOL UAV) and a midwave infrared (MWIR) sensor on a fixed wing aircraft. The system is described and results of the various tests conducted to date are presented.

  15. Solid-State Cloud Radar System (CRS) Upgrade and Deployment

    NASA Technical Reports Server (NTRS)

    McLinden, Matt; Heymsfield, Gerald; Li, Lihua; Racette, Paul; Coon, Michael; Venkatesh, Vijay

    2015-01-01

    The recent decade has brought rapid development in solid-state power amplifier (SSPA) technology. This has enabled the use of solid-state precipitation radar in place of high-power and high-voltage systems such as those that use Klystron or Magnetron transmitters. The NASA Goddard Space Flight Center has recently completed a comprehensive redesign of the 94 gigahertz Cloud Radar System (CRS) to incorporate a solid-state transmitter. It is the first cloud radar to achieve sensitivity comparable to that of a high-voltage transmitter using solid-state. The NASA Goddard Space Flight Center's Cloud Radar System (CRS) is a 94 gigahertz Doppler radar that flies on the NASA ER-2 high-altitude aircraft. The upgraded CRS system utilizes a state-of-the-art solid-state 94 gigahertz power amplifier with a peak transmit power of 30 watts. The modernized CRS system is detailed here with data results from its deployment during the 2014 Integrated Precipitation and Hydrology Experiment (IPHEX).

  16. Airborne antenna polarization study for the microwave landing system

    NASA Technical Reports Server (NTRS)

    Gilreath, M. C.

    1976-01-01

    The feasibility of the microwave landing system (MLS) airborne antenna pattern coverage requirements are investigated for a large commercial aircraft using a single omnidirectional antenna. Omnidirectional antennas having vertical and horizontal polarizations were evaluated at several different station locations on a one-eleventh scale model Boeing 737 aircraft. The results obtained during this experimental program are presented which include principal plane antenna patterns and complete volumetric coverage plots.

  17. Inter-agency Working Group for Airborne Data and Telemetry Systems (IWGADTS)

    NASA Technical Reports Server (NTRS)

    Webster, Chris; Freudinge, Lawrence; Sorenson, Carl; Myers, Jeff; Sullivan, Don; Oolman, Larry

    2009-01-01

    The Interagency Coordinating Committee for Airborne Geosciences Research and Applications (ICCAGRA) was established to improve cooperation and communication among agencies sponsoring airborne platforms and instruments for research and applications, and to serve as a resource for senior level management on airborne geosciences issues. The Interagency Working Group for Airborne Data and Telecommunications Systems (IWGADTS) is a subgroup to ICCAGRA for the purpose of developing recommendations leading to increased interoperability among airborne platforms and instrument payloads, producing increased synergy among research programs with similar goals, and enabling the suborbital layer of the Global Earth Observing System of Systems.

  18. Development of land based radar polarimeter processor system

    NASA Technical Reports Server (NTRS)

    Kronke, C. W.; Blanchard, A. J.

    1983-01-01

    The processing subsystem of a land based radar polarimeter was designed and constructed. This subsystem is labeled the remote data acquisition and distribution system (RDADS). The radar polarimeter, an experimental remote sensor, incorporates the RDADS to control all operations of the sensor. The RDADS uses industrial standard components including an 8-bit microprocessor based single board computer, analog input/output boards, a dynamic random access memory board, and power supplis. A high-speed digital electronics board was specially designed and constructed to control range-gating for the radar. A complete system of software programs was developed to operate the RDADS. The software uses a powerful real time, multi-tasking, executive package as an operating system. The hardware and software used in the RDADS are detailed. Future system improvements are recommended.

  19. Quantitative data quality metrics for 3D laser radar systems

    NASA Astrophysics Data System (ADS)

    Stevens, Jeffrey R.; Lopez, Norman A.; Burton, Robin R.

    2011-06-01

    Several quantitative data quality metrics for three dimensional (3D) laser radar systems are presented, namely: X-Y contrast transfer function, Z noise, Z resolution, X-Y edge & line spread functions, 3D point spread function and data voids. These metrics are calculated from both raw and/or processed point cloud data, providing different information regarding the performance of 3D imaging laser radar systems and the perceptual quality attributes of 3D datasets. The discussion is presented within the context of 3D imaging laser radar systems employing arrays of Geiger-mode Avalanche Photodiode (GmAPD) detectors, but the metrics may generally be applied to linear mode systems as well. An example for the role of these metrics in comparison of noise removal algorithms is also provided.

  20. Algorithms used in the Airborne Lidar Processing System (ALPS)

    USGS Publications Warehouse

    Nagle, David B.; Wright, C. Wayne

    2016-05-23

    The Airborne Lidar Processing System (ALPS) analyzes Experimental Advanced Airborne Research Lidar (EAARL) data—digitized laser-return waveforms, position, and attitude data—to derive point clouds of target surfaces. A full-waveform airborne lidar system, the EAARL seamlessly and simultaneously collects mixed environment data, including submerged, sub-aerial bare earth, and vegetation-covered topographies.ALPS uses three waveform target-detection algorithms to determine target positions within a given waveform: centroid analysis, leading edge detection, and bottom detection using water-column backscatter modeling. The centroid analysis algorithm detects opaque hard surfaces. The leading edge algorithm detects topography beneath vegetation and shallow, submerged topography. The bottom detection algorithm uses water-column backscatter modeling for deeper submerged topography in turbid water.The report describes slant range calculations and explains how ALPS uses laser range and orientation measurements to project measurement points into the Universal Transverse Mercator coordinate system. Parameters used for coordinate transformations in ALPS are described, as are Interactive Data Language-based methods for gridding EAARL point cloud data to derive digital elevation models. Noise reduction in point clouds through use of a random consensus filter is explained, and detailed pseudocode, mathematical equations, and Yorick source code accompany the report.

  1. Algorithms used in the Airborne Lidar Processing System (ALPS)

    USGS Publications Warehouse

    Nagle, David B.; Wright, C. Wayne

    2016-01-01

    The Airborne Lidar Processing System (ALPS) analyzes Experimental Advanced Airborne Research Lidar (EAARL) data—digitized laser-return waveforms, position, and attitude data—to derive point clouds of target surfaces. A full-waveform airborne lidar system, the EAARL seamlessly and simultaneously collects mixed environment data, including submerged, sub-aerial bare earth, and vegetation-covered topographies.ALPS uses three waveform target-detection algorithms to determine target positions within a given waveform: centroid analysis, leading edge detection, and bottom detection using water-column backscatter modeling. The centroid analysis algorithm detects opaque hard surfaces. The leading edge algorithm detects topography beneath vegetation and shallow, submerged topography. The bottom detection algorithm uses water-column backscatter modeling for deeper submerged topography in turbid water.The report describes slant range calculations and explains how ALPS uses laser range and orientation measurements to project measurement points into the Universal Transverse Mercator coordinate system. Parameters used for coordinate transformations in ALPS are described, as are Interactive Data Language-based methods for gridding EAARL point cloud data to derive digital elevation models. Noise reduction in point clouds through use of a random consensus filter is explained, and detailed pseudocode, mathematical equations, and Yorick source code accompany the report.

  2. A fully photonics-based coherent radar system.

    PubMed

    Ghelfi, Paolo; Laghezza, Francesco; Scotti, Filippo; Serafino, Giovanni; Capria, Amerigo; Pinna, Sergio; Onori, Daniel; Porzi, Claudio; Scaffardi, Mirco; Malacarne, Antonio; Vercesi, Valeria; Lazzeri, Emma; Berizzi, Fabrizio; Bogoni, Antonella

    2014-03-20

    The next generation of radar (radio detection and ranging) systems needs to be based on software-defined radio to adapt to variable environments, with higher carrier frequencies for smaller antennas and broadened bandwidth for increased resolution. Today's digital microwave components (synthesizers and analogue-to-digital converters) suffer from limited bandwidth with high noise at increasing frequencies, so that fully digital radar systems can work up to only a few gigahertz, and noisy analogue up- and downconversions are necessary for higher frequencies. In contrast, photonics provide high precision and ultrawide bandwidth, allowing both the flexible generation of extremely stable radio-frequency signals with arbitrary waveforms up to millimetre waves, and the detection of such signals and their precise direct digitization without downconversion. Until now, the photonics-based generation and detection of radio-frequency signals have been studied separately and have not been tested in a radar system. Here we present the development and the field trial results of a fully photonics-based coherent radar demonstrator carried out within the project PHODIR. The proposed architecture exploits a single pulsed laser for generating tunable radar signals and receiving their echoes, avoiding radio-frequency up- and downconversion and guaranteeing both the software-defined approach and high resolution. Its performance exceeds state-of-the-art electronics at carrier frequencies above two gigahertz, and the detection of non-cooperating aeroplanes confirms the effectiveness and expected precision of the system. PMID:24646997

  3. A fully photonics-based coherent radar system

    NASA Astrophysics Data System (ADS)

    Ghelfi, Paolo; Laghezza, Francesco; Scotti, Filippo; Serafino, Giovanni; Capria, Amerigo; Pinna, Sergio; Onori, Daniel; Porzi, Claudio; Scaffardi, Mirco; Malacarne, Antonio; Vercesi, Valeria; Lazzeri, Emma; Berizzi, Fabrizio; Bogoni, Antonella

    2014-03-01

    The next generation of radar (radio detection and ranging) systems needs to be based on software-defined radio to adapt to variable environments, with higher carrier frequencies for smaller antennas and broadened bandwidth for increased resolution. Today's digital microwave components (synthesizers and analogue-to-digital converters) suffer from limited bandwidth with high noise at increasing frequencies, so that fully digital radar systems can work up to only a few gigahertz, and noisy analogue up- and downconversions are necessary for higher frequencies. In contrast, photonics provide high precision and ultrawide bandwidth, allowing both the flexible generation of extremely stable radio-frequency signals with arbitrary waveforms up to millimetre waves, and the detection of such signals and their precise direct digitization without downconversion. Until now, the photonics-based generation and detection of radio-frequency signals have been studied separately and have not been tested in a radar system. Here we present the development and the field trial results of a fully photonics-based coherent radar demonstrator carried out within the project PHODIR. The proposed architecture exploits a single pulsed laser for generating tunable radar signals and receiving their echoes, avoiding radio-frequency up- and downconversion and guaranteeing both the software-defined approach and high resolution. Its performance exceeds state-of-the-art electronics at carrier frequencies above two gigahertz, and the detection of non-cooperating aeroplanes confirms the effectiveness and expected precision of the system.

  4. 78 FR 68861 - Certain Navigation Products, Including GPS Devices, Navigation and Display Systems, Radar Systems...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-15

    ..., Navigational Aids, Mapping Systems and Related Software; Institution of Investigation Pursuant to 19 U.S.C... and display systems, radar systems, navigational aids, mapping systems and related software by reason... products, including GPS devices, navigation and display systems, radar systems, navigational aids,...

  5. System-on-chip based Doppler radar occupancy sensor.

    PubMed

    Yavari, Ehsan; Song, Chenyan; Lubecke, Victor; Boric-Lubecke, Olga

    2011-01-01

    System-on-Chip (SoC) based Doppler radar occupancy sensor is developed through non contact detection of respiratory signals. The radio was developed using off the shelf low power RF CC2530 SoC chip by Texas Instruments. In order to save power, the transmitter sends signal intermittently at 2.405 GHz. Reflected pulses are demodulated, and the baseband signals are processed to recover periodic motion. The system was tested both with mechanical target and a human subject. In both cases Doppler radar detected periodic motion closely matched the actual motion, and it has been shown that an SoC based system can be used for subject detection.

  6. Fiber optic coherent laser radar 3d vision system

    SciTech Connect

    Sebastian, R.L.; Clark, R.B.; Simonson, D.L.

    1994-12-31

    Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic of coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system.

  7. NASA three-laser airborne differential absorption lidar system electronics

    NASA Technical Reports Server (NTRS)

    Allen, R. J.; Copeland, G. D.

    1984-01-01

    The system control and signal conditioning electronics of the NASA three laser airborne differential absorption lidar (DIAL) system are described. The multipurpose DIAL system was developed for the remote measurement of gas and aerosol profiles in the troposphere and lower stratosphere. A brief description and photographs of the majority of electronics units developed under this contract are presented. The precision control system; which includes a master control unit, three combined NASA laser control interface/quantel control units, and three noise pulse discriminator/pockels cell pulser units; is described in detail. The need and design considerations for precision timing and control are discussed. Calibration procedures are included.

  8. Airborne Advanced Reconfigurable Computer System (ARCS)

    NASA Technical Reports Server (NTRS)

    Bjurman, B. E.; Jenkins, G. M.; Masreliez, C. J.; Mcclellan, K. L.; Templeman, J. E.

    1976-01-01

    A digital computer subsystem fault-tolerant concept was defined, and the potential benefits and costs of such a subsystem were assessed when used as the central element of a new transport's flight control system. The derived advanced reconfigurable computer system (ARCS) is a triple-redundant computer subsystem that automatically reconfigures, under multiple fault conditions, from triplex to duplex to simplex operation, with redundancy recovery if the fault condition is transient. The study included criteria development covering factors at the aircraft's operation level that would influence the design of a fault-tolerant system for commercial airline use. A new reliability analysis tool was developed for evaluating redundant, fault-tolerant system availability and survivability; and a stringent digital system software design methodology was used to achieve design/implementation visibility.

  9. Data acquisition system for Doppler radar vital-sign monitor.

    PubMed

    Vergara, Alexander M; Lubecke, Victor M

    2007-01-01

    Automatic gain control (AGC) units increase the dynamic range of a system to compensate for the limited dynamic range of analog to digital converters. This problem is compounded in wireless systems in which large changes in signal strength are effects of a changing environment. These issues are evident in the direct-conversion Doppler radar vital-sign monitor. Utilizing microwave radar signals reflecting off a human subject, a two-channel quadrature receiver can detect periodic movement resulting from cardio-pulmonary activity. The quadrature signal is analyzed using an arctangent demodulation that extracts vital phase information. A data acquisition (DAQ) system is proposed to deal with issues inherent in arctangent demodulation of a quadrature radar signal.

  10. THz impulse radar for biomedical sensing: nonlinear system behavior

    NASA Astrophysics Data System (ADS)

    Brown, E. R.; Sung, Shijun; Grundfest, W. S.; Taylor, Z. D.

    2014-03-01

    The THz impulse radar is an "RF-inspired" sensor system that has performed remarkably well since its initial development nearly six years ago. It was developed for ex vivo skin-burn imaging, and has since shown great promise in the sensitive detection of hydration levels in soft tissues of several types, such as in vivo corneal and burn samples. An intriguing aspect of the impulse radar is its hybrid architecture which combines the high-peak-power of photoconductive switches with the high-responsivity and -bandwidth (RF and video) of Schottky-diode rectifiers. The result is a very sensitive sensor system in which the post-detection signal-to-noise ratio depends super-linearly on average signal power up to a point where the diode is "turned on" in the forward direction, and then behaves quasi-linearly beyond that point. This paper reports the first nonlinear systems analysis done on the impulse radar using MATLAB.

  11. Airborne water vapor DIAL system development

    NASA Technical Reports Server (NTRS)

    Higdon, Noah S.; Browell, Edward V.; Ponsardin, Patrick; Grossmann, Benoist E.

    1990-01-01

    A differential absorption lidar (DIAL) system developed at NASA Langley Research Center for the remote measurement of atmospheric H2O and aerosols from an aircraft is briefly discussed. This DIAL system utilizes a Nd:YAG laser-pumped dye laser as the off-line transmitter and a narrowband, tunable Alexandrite laser as the on-line transmitter. A 1-m monochromator and a multipass absorption cell are used to position the on-line laser to the center of the H2O line. The receiver system has a 14-in. diameter, f/7 Celestron telescope to collect the backscattered laser light and focus in into the detector optics. Return signals are converted to electrical signals by the optical detector and are digitalized and stored on magnetic tape. The results of fligh tests of the system are shown.

  12. Development of an airborne remote sensing system for crop pest management: System integration and verification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Remote sensing along with Global Positioning Systems, Geographic Information Systems, and variable rate technology has been developed, which scientists can implement to help farmers maximize the economic and environmental benefits of crop pest management through precision agriculture. Airborne remo...

  13. Design of a Radar Based Space Situational Awareness System

    NASA Astrophysics Data System (ADS)

    Liebschwager, T.; Neff, T.; Suess, I. H.; Foerstner, I. R.

    2013-09-01

    Existing SSA-Networks in most cases consist of sensors which originally were not designed for the purpose of detecting or tracking space debris and active satellites. Furthermore there are different kinds of sensors in use which makes it even more complicated to handle all generated data. Therefore it is reasonable to create a network consisting of homogenous sensors, which means sensors of the same type (like radar or optical) and with the same output format of the data. Technologies that are available for detection and tracking of objects (e.g. optical sensors or radar) will be discussed. Focal point will be on operational availability, reliability and obtainable accuracy. It will be shown that Phased Array Radars are the most reasonable technology to be used while creating a sensor network consisting of homogenous sensors. This paper entails to present a proposal for a network of Phased Array Radars configured for this purpose. The system is intended to detect and track objects that are at least as small as objects that can currently be found in the US SSN catalogue. Furthermore potential hazards in different orbits will be evaluated and discussed to optimize the system on these areas. The system is supposed to be able to create an own object catalogue. Therefore perseverative tracking and required capacity will also be considered. On the basis of these considerations the paper shows how to lay-up such a radar-system starting from scratch. Criteria for detection and tracking of objects will be determined. This part of the work contains aspects like choosing the frequency band or tracking-frequencies for different sizes of objects. In the next step the locations for the sensors will be chosen. Based on thoughts about infrastructure it is plausible to place the radar systems on existing observation sites. By analyzing simulations with different numbers of sensors and / or locations several feasible approaches for such a Space Situational Awareness Network will be

  14. The Vaisala Radar-Based Nowcasting System: Updates and Applications

    NASA Astrophysics Data System (ADS)

    Ruzanski, Evan; Chandrasekar, Venkatachalam

    2013-04-01

    The Vaisala radar-based nowcasting system is presented and described. The system, based on the Lagrangian persistence paradigm, is designed to provide targeted quantitative forecasts over the 0-1 h time frame for applications such as aviation, roads, and renewable energy. The Lagrangian persistence paradigm, where extrapolation is performed via motion vectors estimated from past radar observations held constant over the lead time period, is a useful approach for many nowcasting applications. This method has shown effectiveness in estimating translation of a variety of precipitation patterns. Previous research has shown that nowcasting performance can be improved by spatially filtering radar observations and considering only those precipitation scales most representative of pattern motion for prediction or filtering those scales from predicted fields deemed unpredictable by remaining past their lifetimes. Thus, a modular framework capable of assimilating a variety of radar data and leveraging appropriate combinations of data processing features is adopted to provide targeted decision support to end-users. In this regard, the system combines several features previously used separately to enhance performance. A recent update to the system includes a Fourier-based least squares motion estimation method that replaced the cross correlation-based method previously used. This update has shown to provide improvements to skill and runtime for the 0-1 h nowcast horizon using WSR-88D and Vaisala WRM200 C-band radar data for a variety of precipitation events. Operation and favorable performance of the nowcasting system is shown in the context of the Vaisala AviCast product, which uses WSR-88D Level III and surface observations to provide operational nowcasts of liquid water equivalent values to support deicing decision-making at airports. Extrapolated WSR-88D Level III base reflectivity values are converted to liquid water equivalent estimates using a Z-R or Z-S relationship

  15. Distributed micro-radar system for detection and tracking of low-profile, low-altitude targets

    NASA Astrophysics Data System (ADS)

    Gorwara, Ashok; Molchanov, Pavlo

    2016-05-01

    Proposed airborne surveillance radar system can detect, locate, track, and classify low-profile, low-altitude targets: from traditional fixed and rotary wing aircraft to non-traditional targets like unmanned aircraft systems (drones) and even small projectiles. Distributed micro-radar system is the next step in the development of passive monopulse direction finder proposed by Stephen E. Lipsky in the 80s. To extend high frequency limit and provide high sensitivity over the broadband of frequencies, multiple angularly spaced directional antennas are coupled with front end circuits and separately connected to a direction finder processor by a digital interface. Integration of antennas with front end circuits allows to exclude waveguide lines which limits system bandwidth and creates frequency dependent phase errors. Digitizing of received signals proximate to antennas allows loose distribution of antennas and dramatically decrease phase errors connected with waveguides. Accuracy of direction finding in proposed micro-radar in this case will be determined by time accuracy of digital processor and sampling frequency. Multi-band, multi-functional antennas can be distributed around the perimeter of a Unmanned Aircraft System (UAS) and connected to the processor by digital interface or can be distributed between swarm/formation of mini/micro UAS and connected wirelessly. Expendable micro-radars can be distributed by perimeter of defense object and create multi-static radar network. Low-profile, lowaltitude, high speed targets, like small projectiles, create a Doppler shift in a narrow frequency band. This signal can be effectively filtrated and detected with high probability. Proposed micro-radar can work in passive, monostatic or bistatic regime.

  16. Gadanki Ionospheric Radar Interferometer (GIRI): System Description, Capabilities and Observations

    NASA Astrophysics Data System (ADS)

    Durga rao, Meka; Jayaraman, Achuthan; Patra, Amit; Kamaraj, Pandian; Jayaraj, Katta; Raghavendra, J.; Yasodha, Polisetti

    2016-07-01

    A 30-MHz radar has been developed at National Atmospheric Research Laboratory for dedicated probing of ionosphere and to study the low latitude ionospheric plasma irregularities. The radar has the beam steering capability to scan a larger part of the sky up to ±45o in East-West direction, which will overcome the limitation of slit camera picture obtained by the fixed beam of the Gadanki MST radar on the ionospheric plasma irregularity/structures. The system is also configured for pulse-to-pulse beam steering, employs multi-channel receiving system to carryout Interferometry/Imaging experiments. The radar system employs 20x8 phased antenna array, Direct Digital Synthesizers to generate pulse coded excitation signals, high power solid-state Transmit-Receive modules to generate a peak power of 150 kW, low loss coaxial beam forming and feeder network and multi-channel direct IF digital receiver. Round-the-clock observations are being made with uninterrupted operations and high quality E-and F-Region Range-Time-Intensity and conical maps are obtained with the system. In this paper we present, the system design philosophy, realization, initial observations and also the capability of the system to augment for Meteor observations.

  17. The GeoSAR program: Development of a commercially viable 3-D radar terrain mapping system

    SciTech Connect

    Carlisle, R.G.; Davis, M.

    1996-11-01

    GeoSAR is joint development between the Defense Advanced Research Project Agency (DARPA) and the California Department of Conservation (CA DOC) to determine the technical and economic viability of an airborne interferometric and foliage penetration synthetic aperture radar for mapping terrain and man made objects in geographical areas obscured by foliage, urban buildings, and other concealments. The two core technology elements of this program are Interferometric Synthetic Aperture Radar (IFSAR) and Foliage Penetration Radar (FOPEN). These technologies have been developed by NASA and ARPA, principally for defense applications.

  18. An airborne laser polarimeter system (ALPS) for terrestrial physics research

    NASA Technical Reports Server (NTRS)

    Kalshoven, James E., Jr.; Dabney, Philip W.

    1988-01-01

    The design of a multispectral polarized laser system for characterizing the depolarization properties of the earth's surface is described. Using a laser as the light source, this airborne system measures the Stokes parameters of the surface to simultaneously arrive at the polarization degree, azimuthal angle, and ellipticity for each wavelength. The technology will be studied for the feasibility of expansion of the sensor to do surface polarization imaging. The data will be used in support of solar polarization studies and to develop laser radiometry as a tool in environmental remote sensing.

  19. Modular airborne remote sampling and sensing system (MARSSS)

    SciTech Connect

    Woods, R.O.

    1982-04-01

    Sandia is developing a modular airborne instrumentation system for the Environmental Protection Agency. This system will allow flexibility in the choice of instruments by standardizing mountings, power supplies and sampling modes. The objective is to make it possible to perform aerial surveys from chartered aircraft that have not been adapted in a more than superficial manner. It will also allow the experimenter to tailor his choice of instruments to the specific problem. Since the equipment will have a stand-alone capability, it can be applied to other problems such as long-term unattended use at remote locations or in toxic or otherwise hazardous environments.

  20. Composite design of an advanced airborne monitoring system

    SciTech Connect

    Busness, K. M.; Alkezweeny, A. J.; Easter, R. C.; Hales, J. M.; Lee, R. N.

    1981-12-01

    Atmospheric chemistry investigations often require a multitude of measurements which can be obtained only through the utilization of airborne sampling platforms. Instrument limitations and the aircraft environment present several considerations for sampling-system design, including such factors as instrument sensitivities and response times, altitude effects, sampling intervals for acquiring samples, and physical compatibility with the aircraft. An aircraft system with an extensive evolutionary instrument array has been in development at PNL for several years during which several special systems have been developed to improve aircraft measurement capabilities. A high-volume air sampling system providing flows of up to 4 m/sup 3//min and simultaneous collection of three filters in parallel has been constructued to reduce filter collection times. A constant pressure inlet system was developed to overcome adverse effects in instrument response resulting from altitude changes. The system functions so that instruments which are connected experinece a constant pre-set pressure regardless of the sampling altitude. This system is particularly useful for airborne operation of a flame photometric sulfur analyzer. Special chemiluminescence NO/NO/sub x/ analyzers utilizing photon counting were built which are capable of fast response and detecton of concentrations in the sub-ppB range.

  1. Methods And System Suppressing Clutter In A Gain-Block, Radar-Responsive Tag System

    DOEpatents

    Ormesher, Richard C.; Axline, Robert M.

    2006-04-18

    Methods and systems reduce clutter interference in a radar-responsive tag system. A radar transmits a series of linear-frequency-modulated pulses and receives echo pulses from nearby terrain and from radar-responsive tags that may be in the imaged scene. Tags in the vicinity of the radar are activated by the radar's pulses. The tags receive and remodulate the radar pulses. Tag processing reverses the direction, in time, of the received waveform's linear frequency modulation. The tag retransmits the remodulated pulses. The radar uses a reversed-chirp de-ramp pulse to process the tag's echo. The invention applies to radar systems compatible with coherent gain-block tags. The invention provides a marked reduction in the strength of residual clutter echoes on each and every echo pulse received by the radar. SAR receiver processing effectively whitens passive-clutter signatures across the range dimension. Clutter suppression of approximately 14 dB is achievable for a typical radar system.

  2. Development of a Low-Cost UAV Doppler Radar Data System

    NASA Technical Reports Server (NTRS)

    Knuble, Joseph; Li, Lihua; Heymsfield, Gerry

    2005-01-01

    A viewgraph presentation on the design of a low cost unmanned aerial vehicle (UAV) doppler radar data system is presented. The topics include: 1) Science and Mission Background; 2) Radar Requirements and Specs; 3) Radar Realization: RF System; 4) Processing of RF Signal; 5) Data System Design Process; 6) Can We Remove the DSP? 7) Determining Approximate Speed Requirements; 8) Radar Realization: Data System; 9) Data System Operation; and 10) Results.

  3. Transmitter Pulse Estimation and Measurements for Airborne TDEM Systems

    NASA Astrophysics Data System (ADS)

    Vetrov, A.; Mejzr, I.

    2013-12-01

    The processing and interpretation of Airborne Time Domain EM data requires precise description of the transmitter parameters, including shape, amplitude and length of the transmitted pulse. There are several ways to measure pulse shape of the transmitter loop. Transmitted pulse can be recorded by a current monitor installed on the loop. The current monitor readings do not give exact image due to own time-domain physical characteristics of the current monitor. Another way is to restore the primary pulse shape from the receiver data recorded on-time, if such is possible. The receiver gives exact image of the primary field projection combined with the ground response, which can be minimized at high altitude pass, usually with a transmitter elevation higher than 1500 ft from the ground. The readings on the receiver are depending on receiver position and orientation. Modeling of airborne TDEM transmitter pulse allows us to compare estimated and measured shape of the pulse and apply required corrections. Airborne TDEM system transmitter pulse shape has been studied by authors while developing P-THEM system. The data has been gathered during in-doors and out-doors ground tests in Canada, as well as during flight tests in Canada and in India. The P-THEM system has three-axes receiver that is suspended on a tow-cable in the midpoint between the transmitter and the helicopter. The P-THEM receiver geometry does not require backing coils to dump the primary field. The system records full-wave data from the receiver and current monitor installed on the transmitter loop, including on-time and off-time data. The modeling of the transmitter pulse allowed us to define the difference between estimated and measured values. The higher accuracy pulse shape can be used for better data processing and interpretation. A developed model can be applied to similar systems and configurations.

  4. An airborne low SWaP-C UAS sense and avoid system

    NASA Astrophysics Data System (ADS)

    Wang, Zhonghai; Lin, Xingping; Xiang, Xingyu; Blasch, Erik; Pham, Khanh; Chen, Genshe; Shen, Dan; Jia, Bin; Wang, Gang

    2016-05-01

    This paper presents a low size, weight and power - cost (SWaP-C) airborne sense and avoid (ABSAA) system, which is based on a linear frequency modulated continuous wave (LFMCW) radar and can be mounted on small unmanned aircraft system (UAS). The system satisfies the constraint of the available sources on group 2/3 UAS. To obtain the desired sense and avoid range, a narrow band frequency (or range) scanning technique is applied for reducing the receiver's noise floor to improve its sensitivity, and a digital signal integration with fast Fourier transform (FFT) is applied to enhance the signal to noise ratio (SNR). The gate length and chirp rate are intelligently adapted to not only accommodate different object distances, speeds and approaching angle conditions, but also optimize the detection speed, resolution and coverage range. To minimize the radar blind zone, a higher chirp rate and a narrowband intermediate frequency (IF) filter are applied at the near region with a single antenna signal for target detection. The offset IF frequency between transmitter (TX) and receiver (RX) is designed to mitigate the TX leakage to the receiver, especially at close distances. Adaptive antenna gain and beam-width are utilized for searching at far distance and fast 360 degree middle range. For speeding up the system update rate, lower chirp rates and wider IF and baseband filters are applied for obtaining larger range scanning step length out of the near region. To make the system working with a low power transmitter (TX), multiple-antenna beamforming, digital signal integration with FFT, and a much narrower receiver (RX) bandwidth are applied at the far region. The ABSAA system working range is 2 miles with a 1W transmitter and single antenna signal detection, and it is 5 miles when a 5W transmitter and 4-antenna beamforming (BF) are applied.

  5. Certification methodology applied to the NASA experimental radar system

    NASA Technical Reports Server (NTRS)

    Britt, Charles L.; Switzer, George F.; Bracalente, Emedio M.

    1994-01-01

    The objective of the research is to apply selected FAA certification techniques to the NASA experimental wind shear radar system. Although there is no intent to certify the NASA system, the procedures developed may prove useful to manufacturers that plan to undergo the certification process. The certification methodology for forward-looking wind shear detection radars will require estimation of system performance in several FAA-specified microburst/clutter scenarios as well as the estimation of probabilities of missed and false hazard alerts under general operational conditions. Because of the near-impossibility of obtaining these results experimentally, analytical and simulation approaches must be used. Hazard detection algorithms were developed that derived predictive estimates of aircraft hazard from basic radar measurements of weather reflectivity and radial wind velocity. These algorithms were designed to prevent false alarms due to ground clutter while providing accurate predictions of hazard to the aircraft due to weather. A method of calculation of the probability of missed and false hazard alerts has been developed that takes into account the effect of the various algorithms used in the system and provides estimates of the probability of missed and false alerts per microburst encounter under weather conditions found at Denver, Kansas City, and Orlando. Simulation techniques have been developed that permit the proper merging of radar ground clutter data (obtained from flight tests) with simulated microburst data (obtained from microburst models) to estimate system performance using the microburst/clutter scenarios defined by the FAA.

  6. A study of cost-effectiveness of low altitude coverage over ground by air surveillance radars

    NASA Astrophysics Data System (ADS)

    Li, Neng-Jing

    Three schemes of low-altitude coverage over ground by air surveillance radars are discussed. They are the ground radar netting, the balloon lifted radars, and the AEW (airborne early warning) system. The cost-effectiveness of each scheme is analyzed and compared with others. The results show that for peacetime use the balloon radar is the best and AEW the worst, but in wartime the conclusion is reversed.

  7. Weather Radar

    NASA Astrophysics Data System (ADS)

    Vivekanandan, Jothiram

    2004-10-01

    Weather radar is an indispensable component for remote sensing of the atmosphere, and the data and products derived from weather radar are routinely used in climate and weather-related studies to examine trends, structure, and evolution. The need for weather remote sensing is driven by the necessity to understand and explain a specific atmospheric science phenomenon. The importance of remote sensing is especially evident in high-profile observational programs, such as the WSR-88D (Weather Surveillance Radar) network, TRMM (Tropical Rainfall Measuring Mission), and ARM (Atmospheric Radiation Measurement). A suite of ground-based and airborne radar instruments is maintained and deployed for observing wind, clouds, and precipitation. Weather radar observation has become an integral component of weather forecasting and hydrology and climate studies. The inclusion of weather radar observations in numerical weather modeling has enhanced severe storm forecasting, aviation weather, hurricane intensity and movement, and the global water cycle.

  8. Feasibility study of a microwave radar system for agricultural inspection

    SciTech Connect

    Okelo-Odongo, S.

    1994-10-03

    The feasibility of an impulse radar system for agricultural inspection is investigated. This system would be able to quickly determine the quality of foodstuffs that are passed through the system. A prototype was designed at the Lawrence Livermore National Laboratory and this report discusses it`s evaluation. A variety of apples were used to test the system and preliminary data suggests that this technology holds promise for successful application on a large scale in food processing plants.

  9. 29 CFR 1915.85 - Vessel radar and communication systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... vessel's radar and communication systems in accordance with 29 CFR 1915.89, Control of Hazardous Energy... 1915.85 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT...

  10. Airborne retrieval of cirrus cloud optical and microphysical properties using Airborne Remote Earth Sensing System 5.1-5.3 and 3.7-μm channel data

    NASA Astrophysics Data System (ADS)

    Ou, S. C.; Liou, K. N.; Yang, P.; Rolland, P.; Caudill, T. R.; Lisowski, J.; Morrison, B.

    1998-09-01

    We present an airborne retrieval algorithm to infer cirrus cloud temperature, optical depth, and mean effective sizes using the Airborne Remote Earth Sensing System (ARES) hyperspectral spectrometer data for the 5.1-5.3 and 3.7 μm channels. The algorithm, development and the selection of the channels are based on the principle and parameterization of radiative transfer involving cirrus clouds and the associated atmospheric and surface properties. It has been applied to a selected case of the ARES data collected over the western Boston area on September 16, 1995. Validation of the retrieved parameters was carried out using the collocated and coincident ground-based 8.6-mm radar data and ice crystal size distribution measurements obtained from the 2D-P probe on board the high-altitude reconnaissance platform (HARP). We show that the retrieved cirrus cloud temperature, mean effective ice crystal size, and optical depth match closely with those derived from the observations.

  11. Simultaneous dual-band radar development

    NASA Technical Reports Server (NTRS)

    Liskow, C. L.

    1974-01-01

    Efforts to design and construct an airborne imaging radar operating simultaneously at L band and X band with an all-inertial navigation system in order to form a dual-band radar system are described. The areas of development include duplex transmitters, receivers, and recorders, a control module, motion compensation for both bands, and adaptation of a commercial inertial navigation system. Installation of the system in the aircraft and flight tests are described. Circuit diagrams, performance figures, and some radar images are presented.

  12. An airborne remote sensing system for urban air quality

    NASA Technical Reports Server (NTRS)

    Duncan, L. J.; Friedman, E. J.; Keitz, E. L.; Ward, E. A.

    1974-01-01

    Several NASA sponsored remote sensors and possible airborne platforms were evaluated. Outputs of dispersion models for SO2 and CO pollution in the Washington, D.C. area were used with ground station data to establish the expected performance and limitations of the remote sensors. Aircraft/sensor support requirements are discussed. A method of optimum flight plan determination was made. Cost trade offs were performed. Conclusions about the implementation of various instrument packages as parts of a comprehensive air quality monitoring system in Washington are presented.

  13. Prediction and removal of rotation noise in airborne EM systems

    NASA Astrophysics Data System (ADS)

    Kratzer, Terence 12Macnae, James

    2014-03-01

    We aim to eliminate or reduce significant impediments to conductive target detection and conductive cover penetration in airborne electromagnetic (AEM) systems. Existing limitations come from the very high noise encountered at low base frequencies, caused by rotations of vector magnetic field sensors in the Earth's magnetic field. We use the output of tri-axial rotation-rate sensors to predict and subtract the rotation noise from rigidly coupled ARMIT magnetic field sensors. The approach is successful in reducing rotation noise by one to two orders of magnitude at low frequencies.

  14. Airborne tunable diode laser system for trace gas measurements

    NASA Technical Reports Server (NTRS)

    Sachse, G. W.; Hill, G. F.; Hoell, J. M., Jr.

    1983-01-01

    Sachse et al. (1976) have reported the development of an airborne tunable diode laser (TDL) system, named the Differential Absorption CO Monitor (DACOM). The absorption path was 10 m long and located in the free airstream along the fuselage of a C-54 aircraft. The present investigation is concerned with a modification of the DACOM instrument. Differences between the new instrument and the original one are related to a replacement of the external absorption path with a White cell. The instrument has the capability to suppress TDL excess noise. The laser refrigerator has been redesigned to permit an alternative method of cooling the TDL when electric power is not available.

  15. Performance assessment of MEMS adaptive optics in tactical airborne systems

    NASA Astrophysics Data System (ADS)

    Tyson, Robert K.

    1999-09-01

    Tactical airborne electro-optical systems are severely constrained by weight, volume, power, and cost. Micro- electrical-mechanical adaptive optics provide a solution that addresses the engineering realities without compromising spatial and temporal compensation requirements. Through modeling and analysis, we determined that substantial benefits could be gained for laser designators, ladar, countermeasures, and missile seekers. The developments potential exists for improving seeker imagery resolution 20 percent, extending countermeasures keep-out range by a factor of 5, doubling the range for ladar detection and identification, and compensating for supersonic and hypersonic aircraft boundary layers. Innovative concepts are required for atmospheric pat hand boundary layer compensation. We have developed design that perform these tasks using high speed scene-based wavefront sensing, IR aerosol laser guide stars, and extended-object wavefront beacons. We have developed a number of adaptive optics system configurations that met the spatial resolution requirements and we have determined that sensing and signal processing requirements can be met. With the help of micromachined deformable mirrors and sensor, we will be able to integrate the systems into existing airborne pods and missiles as well as next generation electro-optical systems.

  16. Advantages to Geoscience and Disaster Response from QuakeSim Implementation of Interferometric Radar Maps in a GIS Database System

    NASA Astrophysics Data System (ADS)

    Parker, Jay; Donnellan, Andrea; Glasscoe, Margaret; Fox, Geoffrey; Wang, Jun; Pierce, Marlon; Ma, Yu

    2015-08-01

    High-resolution maps of earth surface deformation are available in public archives for scientific interpretation, but are primarily available as bulky downloads on the internet. The NASA uninhabited aerial vehicle synthetic aperture radar (UAVSAR) archive of airborne radar interferograms delivers very high resolution images (approximately seven meter pixels) making remote handling of the files that much more pressing. Data exploration requiring data selection and exploratory analysis has been tedious. QuakeSim has implemented an archive of UAVSAR data in a web service and browser system based on GeoServer (http://geoserver.org). This supports a variety of services that supply consistent maps, raster image data and geographic information systems (GIS) objects including standard earthquake faults. Browsing the database is supported by initially displaying GIS-referenced thumbnail images of the radar displacement maps. Access is also provided to image metadata and links for full file downloads. One of the most widely used features is the QuakeSim line-of-sight profile tool, which calculates the radar-observed displacement (from an unwrapped interferogram product) along a line specified through a web browser. Displacement values along a profile are updated to a plot on the screen as the user interactively redefines the endpoints of the line and the sampling density. The profile and also a plot of the ground height are available as CSV (text) files for further examination, without any need to download the full radar file. Additional tools allow the user to select a polygon overlapping the radar displacement image, specify a downsampling rate and extract a modest sized grid of observations for display or for inversion, for example, the QuakeSim simplex inversion tool which estimates a consistent fault geometry and slip model.

  17. The design and evaluation of a 5.8 ghz laptop-based radar system

    NASA Astrophysics Data System (ADS)

    Teng, Kevin Chi-Ming

    This project involves design and analysis of a 5.8 GHz laptop-based radar system. The radar system measures Doppler, ranging and forming Synthetic Aperture Radar (SAR) images utilizing Matlab software provided from MIT Open Courseware and performs data acquisition and signal processing. The main purpose of this work is to bring new perspective to the existing radar project by increasing the ISM band frequency from 2.4 GHz to 5.8 GHz and to carry out a series of experiments on the implementation of the radar kit. Demonstrating the radar at higher operating frequency is capable of providing accurate data results in Doppler, ranging and SAR images.

  18. A Real-Time Advisory System For Airborne Early Warning

    NASA Astrophysics Data System (ADS)

    Kirk, D. B.; Cromwell, M. E.; Donnell, M. L.; Barrett, C. L.

    1987-05-01

    Decision speed and quality can be greatly enhanced by the use of decision augmentation software to assist operators in information analysis and tactical problem solving, dynamic resource allocation, and in determining strategies which optimize overall system performance. One example of such software is the real-time advisory system (RTAS) being constructed to assist in tactical decision-making for airborne early warning (AEW) aircraft, particularly the carrier-based Navy E-2C. Using a vector logic approach, the current AEW RTAS is a real-time backward chaining expert system which provides advice for both threat interception and refueling in the complex Outer Air Battle Scenario. This paper describes the current system, discusses a number of design issues for such a system, and describes ongoing modifications to the current AEW RTAS using SAIC's frame-based knowledge repre-sentation language (KRL).

  19. Comparison of millimeter-wave cloud radar measurements for the Fall 1997 Cloud IOP

    SciTech Connect

    Sekelsky, S.M.; Li, L.; Galloway, J.; McIntosh, R.E.; Miller, M.A.; Clothiaux, E.E.; Haimov, S.; Mace, G.; Sassen, K.

    1998-05-01

    One of the primary objectives of the Fall 1997 IOP was to intercompare Ka-band (350Hz) and W-band (95GHz) cloud radar observations and verify system calibrations. During September 1997, several cloud radars were deployed at the Southern Great Plains (SOP) Cloud and Radiation Testbed (CART) site, including the full time operation 35 GHz CART Millimeter-wave Cloud Radar (MMCR), the University of Massachusetts (UMass) single antenna 33GHz/95 GHz Cloud Profiling Radar System (CPRS), the 95 GHz Wyoming Cloud Radar (WCR) flown on the University of Wyoming King Air, the University of Utah 95 GHz radar and the dual-antenna Pennsylvania State University 94 GHz radar. In this paper the authors discuss several issues relevant to comparison of ground-based radars, including the detection and filtering of insect returns. Preliminary comparisons of ground-based Ka-band radar reflectivity data and comparisons with airborne radar reflectivity measurements are also presented.

  20. An automated data exploitation system for airborne sensors

    NASA Astrophysics Data System (ADS)

    Chen, Hai-Wen; McGurr, Mike

    2014-06-01

    Advanced wide area persistent surveillance (WAPS) sensor systems on manned or unmanned airborne vehicles are essential for wide-area urban security monitoring in order to protect our people and our warfighter from terrorist attacks. Currently, human (imagery) analysts process huge data collections from full motion video (FMV) for data exploitation and analysis (real-time and forensic), providing slow and inaccurate results. An Automated Data Exploitation System (ADES) is urgently needed. In this paper, we present a recently developed ADES for airborne vehicles under heavy urban background clutter conditions. This system includes four processes: (1) fast image registration, stabilization, and mosaicking; (2) advanced non-linear morphological moving target detection; (3) robust multiple target (vehicles, dismounts, and human) tracking (up to 100 target tracks); and (4) moving or static target/object recognition (super-resolution). Test results with real FMV data indicate that our ADES can reliably detect, track, and recognize multiple vehicles under heavy urban background clutters. Furthermore, our example shows that ADES as a baseline platform can provide capability for vehicle abnormal behavior detection to help imagery analysts quickly trace down potential threats and crimes.

  1. System simulation of a 0.2THz imaging radar

    NASA Astrophysics Data System (ADS)

    Zhu, Li; Deng, Chao; Zhang, Cun-lin; Zhao, Yue-jin

    2009-07-01

    Unlike traditional THz imaging system, we first report a design of 0.2THz stepped frequency radar system, and prove its feasibility by simulation. The stepped frequency radar working from 200GHz to 210GHz can provide centimeter accuracy. To demonstrate the feasibility of our design, we simulate our system by using Advanced Design System (ADS) and Simulink in Matlab. The transmitter line is simulated in ADS, while system-level simulation is carried out in Matlab. The simulation of transmitter is implemented by using parameters from actual products, which can ensure the reality of simulation. In this paper, we will present the methods and results of our simulation. From the results, we can conclude that our design is feasible.

  2. Doppler radar sensor positioning in a fall detection system.

    PubMed

    Liu, Liang; Popescu, Mihail; Ho, K C; Skubic, Marjorie; Rantz, Marilyn

    2012-01-01

    Falling is a common health problem for more than a third of the United States population over 65. We are currently developing a Doppler radar based fall detection system that already has showed promising results. In this paper, we study the sensor positioning in the environment with respect to the subject. We investigate three sensor positions, floor, wall and ceiling of the room, in two experimental configurations. Within each system configuration, subjects performed falls towards or across the radar sensors. We collected 90 falls and 341 non falls for the first configuration and 126 falls and 817 non falls for the second one. Radar signature classification was performed using a SVM classifier. Fall detection performance was evaluated using the area under the ROC curves (AUCs) for each sensor deployment. We found that a fall is more likely to be detected if the subject is falling toward or away from the sensor and a ceiling Doppler radar is more reliable for fall detection than a wall mounted one.

  3. Doppler radar sensor positioning in a fall detection system.

    PubMed

    Liu, Liang; Popescu, Mihail; Ho, K C; Skubic, Marjorie; Rantz, Marilyn

    2012-01-01

    Falling is a common health problem for more than a third of the United States population over 65. We are currently developing a Doppler radar based fall detection system that already has showed promising results. In this paper, we study the sensor positioning in the environment with respect to the subject. We investigate three sensor positions, floor, wall and ceiling of the room, in two experimental configurations. Within each system configuration, subjects performed falls towards or across the radar sensors. We collected 90 falls and 341 non falls for the first configuration and 126 falls and 817 non falls for the second one. Radar signature classification was performed using a SVM classifier. Fall detection performance was evaluated using the area under the ROC curves (AUCs) for each sensor deployment. We found that a fall is more likely to be detected if the subject is falling toward or away from the sensor and a ceiling Doppler radar is more reliable for fall detection than a wall mounted one. PMID:23365879

  4. An airborne meteorological data collection system using satellite relay (ASDAR)

    NASA Technical Reports Server (NTRS)

    Bagwell, J. W.; Lindow, B. G.

    1978-01-01

    The National Aeronautics and Space Administration (NASA) has developed an airborne data acquisition and communication system for the National Oceanic and Atmospheric Administration (NOAA). This system known as ASDAR, the Aircraft to Satellite Data Relay, consists of a microprocessor based controller, time clock, transmitter and antenna. Together they acquire meteorological and position information from existing aircraft systems on B-747 aircraft, convert and format these, and transmit them to the ground via the GOES meteorological satellite series. The development and application of the ASDAR system is described with emphasis on unique features. Performance to date is exceptional, providing horizon-to-horizon coverage of aircraft flights. The data collected is of high quality and is considered a valuable addition to the data base from which NOAA generates its weather forecasts.

  5. Laboratory and field portable system for calibrating airborne multispectral scanners

    SciTech Connect

    Kuhlow, W.W.

    1981-01-01

    Manufacturers of airborne multispectral scanners suggest procedures for calibration and alignment that are usually awkward and even questionable. For example, the procedures may require: separating the scanner from calibration and alignment sources by 100 feet or more, employing folding mirrors, tampering with the detectors after the procedures are finished, etc. Under the best of conditions such procedures require about three hours yielding questionable confidence in the results; under many conditions, however, procedures commonly take six to eight hours, yielding no satisfactory results. EG and G, Inc. has designed and built a calibration and alignment system for airborne scanners which solves those problems, permitting the procedures to be carried out in about two to three hours. This equipment can be quickly disassembled, transported with the scanner in all but the smallest single engine aircraft, and reassembled in a few hours. The subsystems of this equipment are commonly available from manufacturers of optical and electronic equipment. The other components are easily purchased, or fabricated. The scanner discussed is the Model DS-1260 digital line scanner manufactured by Daedalus Enterprises, Inc. It is a dual-sensor system which is operated in one of two combination of sensors: one spectrometer head (which provides simultaneous coverage in ten visible channels) and one thermal infrared detector, or simply two thermal infrared detectors.

  6. Potential scientific research which will benefit from an airborne Doppler lidar measurement system

    NASA Technical Reports Server (NTRS)

    Frost, W.

    1980-01-01

    Areas of research which can be significantly aided by the Doppler lidar airborne system are described. The need for systematic development of the airborne Doppler lidar is discussed. The technology development associated with the systematic development of the system will have direct application to satellite systems for which the lidar also promises to be an effective instrument for atmospheric research.

  7. 47 CFR 15.515 - Technical requirements for vehicular radar systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Technical requirements for vehicular radar... DEVICES Ultra-Wideband Operation § 15.515 Technical requirements for vehicular radar systems. (a..., changing gears, or engaging a turn signal. (b) The UWB bandwidth of a vehicular radar system...

  8. 47 CFR 15.515 - Technical requirements for vehicular radar systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Technical requirements for vehicular radar... DEVICES Ultra-Wideband Operation § 15.515 Technical requirements for vehicular radar systems. (a..., changing gears, or engaging a turn signal. (b) The UWB bandwidth of a vehicular radar system...

  9. 47 CFR 15.515 - Technical requirements for vehicular radar systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Technical requirements for vehicular radar... DEVICES Ultra-Wideband Operation § 15.515 Technical requirements for vehicular radar systems. (a..., changing gears, or engaging a turn signal. (b) The UWB bandwidth of a vehicular radar system...

  10. 47 CFR 15.515 - Technical requirements for vehicular radar systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Technical requirements for vehicular radar... DEVICES Ultra-Wideband Operation § 15.515 Technical requirements for vehicular radar systems. (a..., changing gears, or engaging a turn signal. (b) The UWB bandwidth of a vehicular radar system...

  11. 47 CFR 15.515 - Technical requirements for vehicular radar systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Technical requirements for vehicular radar... DEVICES Ultra-Wideband Operation § 15.515 Technical requirements for vehicular radar systems. (a..., changing gears, or engaging a turn signal. (b) The UWB bandwidth of a vehicular radar system...

  12. Fusing enhanced radar precipitation, in-situ hydrometeorological measurements and airborne LIDAR snowpack estimates in a hyper-resolution hydrologic model to improve seasonal water supply forecasts

    NASA Astrophysics Data System (ADS)

    Gochis, D. J.; Busto, J.; Howard, K.; Mickey, J.; Deems, J. S.; Painter, T. H.; Richardson, M.; Dugger, A. L.; Karsten, L. R.; Tang, L.

    2015-12-01

    Scarcity of spatially- and temporally-continuous observations of precipitation and snowpack conditions in remote mountain watersheds results in fundamental limitations in water supply forecasting. These limitationsin observational capabilities can result in strong biases in total snowmelt-driven runoff amount, the elevational distribution of runoff, river basin tributary contributions to total basin runoff and, equally important for water management, the timing of runoff. The Upper Rio Grande River basin in Colorado and New Mexico is one basin where observational deficiencies are hypothesized to have significant adverse impacts on estimates of snowpack melt-out rates and on water supply forecasts. We present findings from a coordinated observational-modeling study within Upper Rio Grande River basin whose aim was to quanitfy the impact enhanced precipitation, meteorological and snowpack measurements on the simulation and prediction of snowmelt driven streamflow. The Rio Grande SNOwpack and streamFLOW (RIO-SNO-FLOW) Prediction Project conducted enhanced observing activities during the 2014-2015 water year. Measurements from a gap-filling, polarimetric radar (NOXP) and in-situ meteorological and snowpack measurement stations were assimilated into the WRF-Hydro modeling framework to provide continuous analyses of snowpack and streamflow conditions. Airborne lidar estimates of snowpack conditions from the NASA Airborne Snow Observatory during mid-April and mid-May were used as additional independent validations against the various model simulations and forecasts of snowpack conditions during the melt-out season. Uncalibrated WRF-Hydro model performance from simulations and forecasts driven by enhanced observational analyses were compared against results driven by currently operational data inputs. Precipitation estimates from the NOXP research radar validate significantly better against independent in situ observations of precipitation and snow-pack increases

  13. The airborne laser ranging system, its capabilities and applications

    NASA Technical Reports Server (NTRS)

    Kahn, W. D.; Degnan, J. J.; Englar, T. S., Jr.

    1982-01-01

    The airborne laser ranging system is a multibeam short pulse laser ranging system on board an aircraft. It simultaneously measures the distances between the aircraft and six laser retroreflectors (targets) deployed on the Earth's surface. The system can interrogate over 100 targets distributed over an area of 25,000 sq, kilometers in a matter of hours. Potentially, a total of 1.3 million individual range measurements can be made in a six hour flight. The precision of these range measurements is approximately + or - 1 cm. These measurements are used in procedure which is basically an extension of trilateration techniques to derive the intersite vector between the laser ground targets. By repeating the estimation of the intersite vector, strain and strain rate errors can be estimated. These quantities are essential for crustal dynamic studies which include determination and monitoring of regional strain in the vicinity of active fault zones, land subsidence, and edifice building preceding volcanic eruptions.

  14. An airborne real-time hyperspectral target detection system

    NASA Astrophysics Data System (ADS)

    Skauli, Torbjorn; Haavardsholm, Trym V.; Kåsen, Ingebjørg; Arisholm, Gunnar; Kavara, Amela; Opsahl, Thomas Olsvik; Skaugen, Atle

    2010-04-01

    An airborne system for hyperspectral target detection is described. The main sensor is a HySpex pushbroom hyperspectral imager for the visible and near-infrared spectral range with 1600 pixels across track, supplemented by a panchromatic line imager. An optional third sensor can be added, either a SWIR hyperspectral camera or a thermal camera. In real time, the system performs radiometric calibration and georeferencing of the images, followed by image processing for target detection and visualization. The current version of the system implements only spectral anomaly detection, based on normal mixture models. Image processing runs on a PC with a multicore Intel processor and an Nvidia graphics processing unit (GPU). The processing runs in a software framework optimized for large sustained data rates. The platform is a Cessna 172 aircraft based close to FFI, modified with a camera port in the floor.

  15. System-on-chip based Doppler radar occupancy sensor.

    PubMed

    Yavari, Ehsan; Song, Chenyan; Lubecke, Victor; Boric-Lubecke, Olga

    2011-01-01

    System-on-Chip (SoC) based Doppler radar occupancy sensor is developed through non contact detection of respiratory signals. The radio was developed using off the shelf low power RF CC2530 SoC chip by Texas Instruments. In order to save power, the transmitter sends signal intermittently at 2.405 GHz. Reflected pulses are demodulated, and the baseband signals are processed to recover periodic motion. The system was tested both with mechanical target and a human subject. In both cases Doppler radar detected periodic motion closely matched the actual motion, and it has been shown that an SoC based system can be used for subject detection. PMID:22254705

  16. Remote sensing at the University of Kansas in radar systems

    NASA Technical Reports Server (NTRS)

    Moore, R. K.

    1970-01-01

    Demonstration that a spectral response across an octave bandwidth in the microwave region is as variable as the comparable response in the visible and infrared region is a major mile-stone and indicates the potential of polypanchromatic radar systems is analogous with that of color photography. Averaging of the returns from a target element appears necessary to obtain a grey scale adequate for many earth-science applications of radar systems. This result can be obtained either by azimuth averaging or by the use of panchromatic techniques (range averaging). Improvement with panchromatic techniques has been demonstrated both with a landbased electromagnetic system and with an ultrasonic simulator. The advantage of the averaging achieved in azimuth with the real-aperture version of the DPD-2 when compared with the synthetic aperture version confirms the concept.

  17. ERS-1 radar altimeter system performance evaluation and calibration

    NASA Astrophysics Data System (ADS)

    Braun, H. M.; Groebke, H.; Hans, P.

    1984-08-01

    The ERS-1 (ESA) radar altimeter system simulation philosophy and simulator development are described. The simulator models system geometry, echo process, uplink/downlink, platform characteristics, instrument processing, ground processing, system errors, and special target characteristics (e.g., reflections from ice surfaces). It supports pre and post launch system-calibration; refinement of the engineering specifications during the ERS-1 development phase; monitoring and controlling of instrument design and development; prelaunch verification of system performance; investigation of inflight malfunctions and compensation of errors during nominal operations; development of echo models; and demonstration of system capabilities in operational cases.

  18. Estimating lava volume by precision combination of multiple baseline spaceborne and airborne interferometric synthetic aperture radar: The 1997 eruption of Okmok Volcano, Alaska

    USGS Publications Warehouse

    Lu, Zhiming; Fielding, E.; Patrick, M.R.; Trautwein, C.M.

    2003-01-01

    Interferometric synthetic aperture radar (InSAR) techniques are used to calculate the volume of extrusion at Okmok volcano, Alaska by constructing precise digital elevation models (DEMs) that represent volcano topography before and after the 1997 eruption. The posteruption DEM is generated using airborne topographic synthetic aperture radar (TOPSAR) data where a three-dimensional affine transformation is used to account for the misalignments between different DEM patches. The preeruption DEM is produced using repeat-pass European Remote Sensing satellite data; multiple interferograms are combined to reduce errors due to atmospheric variations, and deformation rates are estimated independently and removed from the interferograms used for DEM generation. The extrusive flow volume associated with the 1997 eruption of Okmok volcano is 0.154 ?? 0.025 km3. The thickest portion is approximately 50 m, although field measurements of the flow margin's height do not exceed 20 m. The in situ measurements at lava edges are not representative of the total thickness, and precise DEM data are absolutely essential to calculate eruption volume based on lava thickness estimations. This study is an example that demonstrates how InSAR will play a significant role in studying volcanoes in remote areas.

  19. Microwave backscatter and emission observed from Shuttle Imaging Radar B and an airborne 1.4 GHz radiometer

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Schiue, J. C.; Schmugge, T. J.; Engman, E. T.; Mo, T.; Lawrence, R. W.

    1985-01-01

    A soil moisture experiment conducted with the Shuttle Imaging Radar B (SIR-B) is reported. SIR-B operated at 1.28 GHz provided the active microwave measurements, while a 4-beam pushbroom 1.4 GHz radiometer gave the complementary passive microwave measurements. The aircraft measurements were made at an altitude of 330 m, resulting in a ground resolution cell of about 100 m diameter. SIR-B ground resolution from 225 km was about 35 m. More than 150 agricultural fields in the San Joaquin Valley of California were examined in the experiment. The effect of surface roughness height on radar backscatter and radiometric measurements was studied.

  20. Characterization of the airborne activity confinement system prefilter material

    SciTech Connect

    Long, T.A.; Monson, P.R.

    1992-05-01

    A general concern with assessing the effects of postulated severe accidents is predicting and preventing the release of radioactive isotopes to the environment at the Savannah River Site (SRS) reactor. Unless the confinement systems are breached in an accident the Airborne Activity Confinement System forces all of the internal air through the filter compartments. Proper modeling of the radioactivity released to the environment requires knowledge of the filtering characteristics of the demisters, the HEPA`s, and the charcoal beds. An investigation of the mass loading characteristics for a range of particle sizes was performed under the direction of Vince Novick of Argonne National Laboratory (ANL) for the Savannah River Technology Center (SRTC) in connection with the restart of the K reactor. Both solid and liquid aerosols were used to challenge sample prefilter and HEPA filters. The results of the ANL investigation are reported in this document.

  1. Characterization of the airborne activity confinement system prefilter material

    SciTech Connect

    Long, T.A.; Monson, P.R.

    1992-05-01

    A general concern with assessing the effects of postulated severe accidents is predicting and preventing the release of radioactive isotopes to the environment at the Savannah River Site (SRS) reactor. Unless the confinement systems are breached in an accident the Airborne Activity Confinement System forces all of the internal air through the filter compartments. Proper modeling of the radioactivity released to the environment requires knowledge of the filtering characteristics of the demisters, the HEPA's, and the charcoal beds. An investigation of the mass loading characteristics for a range of particle sizes was performed under the direction of Vince Novick of Argonne National Laboratory (ANL) for the Savannah River Technology Center (SRTC) in connection with the restart of the K reactor. Both solid and liquid aerosols were used to challenge sample prefilter and HEPA filters. The results of the ANL investigation are reported in this document.

  2. The Airborne Ocean Color Imager - System description and image processing

    NASA Technical Reports Server (NTRS)

    Wrigley, Robert C.; Slye, Robert E.; Klooster, Steven A.; Freedman, Richard S.; Carle, Mark; Mcgregor, Lloyd F.

    1992-01-01

    The Airborne Ocean Color Imager was developed as an aircraft instrument to simulate the spectral and radiometric characteristics of the next generation of satellite ocean color instrumentation. Data processing programs have been developed as extensions of the Coastal Zone Color Scanner algorithms for atmospheric correction and bio-optical output products. The latter include several bio-optical algorithms for estimating phytoplankton pigment concentration, as well as one for the diffuse attenuation coefficient of the water. Additional programs have been developed to geolocate these products and remap them into a georeferenced data base, using data from the aircraft's inertial navigation system. Examples illustrate the sequential data products generated by the processing system, using data from flightlines near the mouth of the Mississippi River: from raw data to atmospherically corrected data, to bio-optical data, to geolocated data, and, finally, to georeferenced data.

  3. Interference immunity of optical radar system with phased antenna array

    NASA Astrophysics Data System (ADS)

    Alishev, Y. V.; Yamaykin, V. Y.

    1985-03-01

    A phased antenna array of an optical radar system with single-mode or phase-locked sources is analyzed for interference immunity. A major factor influencing the performance as well as the method of analysis is the relative magnitudes of coherence length and path difference, the latter characterizing the interference pattern of light beams and its effect on the antenna radiation pattern. Although a path difference much smaller than the coherence length permits assumption of a quasimonochromatic radiation, interference must be accounted for when the path difference is comparable with the coherence length. The directive gain and the probability of detection error are calculated, assuming Poisson distributions of signal photons with either vertical or horizontal polarization and of noise photons at the receiver input. Estimates indicate that reducing the error probability to below 0.00001 is feasible by phasing the antenna of an optical radar system operating under normal conditions.

  4. Airborne Multisensor Pod System (AMPS) data management overview

    SciTech Connect

    Wiberg, J.D.; Blough, D.K.; Daugherty, W.R.; Hucks, J.A.; Gerhardstein, L.H.; Meitzler, W.D.; Melton, R.B.; Shoemaker, S.V.

    1994-09-01

    An overview of the Data Management Plan for the Airborne Multisensor Pod System (AMPS) pro-grain is provided in this document. The Pacific Northwest Laboratory (PNL) has been assigned the responsibility of data management for the program, which includes defining procedures for data management and data quality assessment. Data management is defined as the process of planning, acquiring, organizing, qualifying and disseminating data. The AMPS program was established by the U.S. Department of Energy (DOE), Office of Arms Control and Non-Proliferation (DOE/AN) and is integrated into the overall DOE AN-10.1 technology development program. Sensors used for collecting the data were developed under the on-site inspection, effluence analysis, and standoff sensor program, the AMPS program interacts with other technology programs of DOE/NN-20. This research will be conducted by both government and private industry. AMPS is a research and development program, and it is not intended for operational deployment, although the sensors and techniques developed could be used in follow-on operational systems. For a complete description of the AMPS program, see {open_quotes}Airborne Multisensor Pod System (AMPS) Program Plan{close_quotes}. The primary purpose of the AMPS is to collect high-quality multisensor data to be used in data fusion research to reduce interpretation problems associated with data overload and to derive better information than can be derived from any single sensor. To collect the data for the program, three wing-mounted pods containing instruments with sensors for collecting data will be flight certified on a U.S. Navy RP-3A aircraft. Secondary objectives of the AMPS program are sensor development and technology demonstration. Pod system integrators and instrument developers will be interested in the performance of their deployed sensors and their supporting data acquisition equipment.

  5. Considerations for integration of a physiological radar monitoring system with gold standard clinical sleep monitoring systems.

    PubMed

    Singh, Aditya; Baboli, Mehran; Gao, Xiaomeng; Yavari, Ehsan; Padasdao, Bryson; Soll, Bruce; Boric-Lubecke, Olga; Lubecke, Victor

    2013-01-01

    A design for a physiological radar monitoring system (PRMS) that can be integrated with clinical sleep monitoring systems is presented. The PRMS uses two radar systems at 2.45 GHz and 24 GHz to achieve both high sensitivity and high resolution. The system can acquire data, perform digital processing and output appropriate conventional analog outputs with a latency of 130 ms, which can be recorded and displayed by a gold standard sleep monitoring system, along with other standard sensor measurements.

  6. Considerations for integration of a physiological radar monitoring system with gold standard clinical sleep monitoring systems.

    PubMed

    Singh, Aditya; Baboli, Mehran; Gao, Xiaomeng; Yavari, Ehsan; Padasdao, Bryson; Soll, Bruce; Boric-Lubecke, Olga; Lubecke, Victor

    2013-01-01

    A design for a physiological radar monitoring system (PRMS) that can be integrated with clinical sleep monitoring systems is presented. The PRMS uses two radar systems at 2.45 GHz and 24 GHz to achieve both high sensitivity and high resolution. The system can acquire data, perform digital processing and output appropriate conventional analog outputs with a latency of 130 ms, which can be recorded and displayed by a gold standard sleep monitoring system, along with other standard sensor measurements. PMID:24110139

  7. The use of airborne radar reflectometry to characterize near-surface snow/firn stratigraphy on Devon Ice Cap, Canadian Arctic: A path to identifying refrozen melt layers

    NASA Astrophysics Data System (ADS)

    Rutishauser, A.; Grima, C.; Sharp, M. J.; Blankenship, D. D.; Young, D. A.; Dowdeswell, J. A.

    2015-12-01

    Under present warming conditions, summer surface melt has been observed to intensify and shift towards higher elevations in the accumulation zones of Canadian Arctic ice caps. Consequently, more meltwater percolates into the near surface snow and firn, and refreezes as ice layers. This process can lead to a significant increase in firn densification rates. Knowledge of spatiotemporal variations of the near-surface firn density, especially the distribution of ice layer formation is of great importance when assessing mass change estimates from repeat altimetry measurements. Here, we present an approach for characterizing the near-surface firn stratigraphy and determining the spatial distribution of refrozen melt layers on Devon Ice Cap, using the surface echo from airborne radio-echo sounding (RES) measurements. The RES surface echo is affected by the upper few meters of snow/firn/ice and thus contains information about the near-surface properties. More specifically, the radar surface return is a combination of a coherent (Pc) and a scattering signal component (Pn). Pc is related to the dielectric constant of the probed surface, whereas Pn is related to the near surface roughness. Hence, different near-surface snow/firn properties can be investigated by analyzing the signal components Pc and Pn and their spatial variability. The Radar Statistical Reconnaissance (RSR) methodology [1] allows the extraction of Pc and Pn from the surface radar return, which then can be used to compute near-surface roughness and firn density estimates. We apply the RSR method to RES data collected on Devon Ice Cap and determine Pc and Pn values. We then compare the results to ground based RES measurements and shallow firn cores (~11 m deep) collected along the airborne RES flight lines. This comparison shows that variations in the scattering coefficient Pn correlate to changes in the pattern of near-surface firn stratigraphy revealed by the ground based RES data and firn cores. Based on

  8. Streamflow Measurement Using A Riversonde Uhf Radar System

    NASA Astrophysics Data System (ADS)

    Teague, C.; Barrick, D.; Lilleboe, P.; Cheng, R.

    Initial field tests have been performed to evaluate the performance of a RiverSonde streamflow measurement system. The tests were conducted at a concrete-lined canal and a natural river in central California during June, 2000. The RiverSonde is a UHF radar operating near 350 MHz and is based on a modified SeaSonde system normally used to measure ocean surface currents in salt water using lower frequencies (5­25 MHz). The RiverSonde uses energy scattered by Bragg-resonant 0.5 m water waves and does not require any sensors in the water. Water velocity is calculated by observing the Doppler shift of the scattered radar energy and comparing that with the Doppler shift expected from resonant waves in still water. The radar has sufficient resolution to allow the estimation of a velocity profile across the width of the river. The antennas consisted of a 2-element transmitting antenna and a 3-element receiving antenna. The transmitting antenna provided broad illumination of the water surface, and MUSIC direction finding was used to determine the arrival direction of the re- flected radar energy. The transmitting and receiving antennas were placed on opposite banks to reduce the signal intensity variation across the channel. A chirp frequency sweep was used to determine range. Transmitted power was under 1 W, and the max- imum range was a few hundred meters. Range resolution was on the order of 10 m, and velocity resolution was about 2.5 cm/s. Extensive in-situ surface truth measurements were performed by personnel from the United States Geological Survey. The instruments included current meters suspended at various depths from a small boat positioned at several locations across the channel, video tracking of many floaters (tennis balls) on the water surface, an optical flow meter, and anemometer wind measurements. Typical water velocities were about 40 cm/s, and RMS velocity differences between the radar and in-situ measurements were 6­18% of the mean flow, with similar

  9. Benefits of Sharing Information from Commercial Airborne Forward-Looking Sensors in the Next Generation Air Transportation System

    NASA Technical Reports Server (NTRS)

    Schaffner, Philip R.; Harrah, Steven; Neece, Robert T.

    2012-01-01

    The air transportation system of the future will need to support much greater traffic densities than are currently possible, while preserving or improving upon current levels of safety. Concepts are under development to support a Next Generation Air Transportation System (NextGen) that by some estimates will need to support up to three times current capacity by the year 2025. Weather and other atmospheric phenomena, such as wake vortices and volcanic ash, constitute major constraints on airspace system capacity and can present hazards to aircraft if encountered. To support safe operations in the NextGen environment advanced systems for collection and dissemination of aviation weather and environmental information will be required. The envisioned NextGen Network Enabled Weather (NNEW) infrastructure will be a critical component of the aviation weather support services, providing access to a common weather picture for all system users. By taking advantage of Network Enabled Operations (NEO) capabilities, a virtual 4-D Weather Data Cube with aviation weather information from many sources will be developed. One new source of weather observations may be airborne forward-looking sensors, such as the X-band weather radar. Future sensor systems that are the subject of current research include advanced multi-frequency and polarimetric radar, a variety of Lidar technologies, and infrared imaging spectrometers.

  10. Clocks for airborne systems. [performance of rubidium oscillators

    NASA Technical Reports Server (NTRS)

    Houlding, N.

    1982-01-01

    The potential performance of compact oscillators, needed for the development of accurate clocks for future airborne systems (such as Identification Friend or Foe schemes), is addressed. In particular, extensive testing of rubidium oscillators manufactured by Efratom is discussed. The results indicate that an accuracy of better than 10 microseconds should be achievable in tactical aircraft provided that appropriate measures are adopted to counter the many environmental factors. In a favorable environment a stability of better than 5 x 10 to the -13th power for one day is achievable with present commercial units, but improvements are required to suit operation in an aircraft. With further development of rubidium controlled clocks the ultimate limitation on time accuracy in aircraft will probably be associated with time dissemination, maintenance difficulties and doctrinal hurdles.

  11. Speckle reduction in CO2 heterodyne laser radar systems

    NASA Astrophysics Data System (ADS)

    Lutzmann, Peter; Ebert, Reinhard R.

    1990-10-01

    A limitation of heterodyne C02-laser radars results from the statistical properties of speckle effects. Suppression of speckle influence by adding uncorrelated speckle pattern was experimentally studied. Using a space separation technique involving a quadrant detector allows to 'look' at different parts of the laser spot on the target at the same time. By choosing the proper diameter of the receiver optics nearly uncorrelated signals are seen with the four detector elements. The signal statistics was measured for direct and heterodyne detection. The achieved improvement in the signal probability distribution and in the contrast were compared with theory. The measurements were done with both a laboratory setup and with the Ff0 Laser-Radar-System BASIS 2.

  12. Transponder-aided joint calibration and synchronization compensation for distributed radar systems.

    PubMed

    Wang, Wen-Qin

    2015-01-01

    High-precision radiometric calibration and synchronization compensation must be provided for distributed radar system due to separate transmitters and receivers. This paper proposes a transponder-aided joint radiometric calibration, motion compensation and synchronization for distributed radar remote sensing. As the transponder signal can be separated from the normal radar returns, it is used to calibrate the distributed radar for radiometry. Meanwhile, the distributed radar motion compensation and synchronization compensation algorithms are presented by utilizing the transponder signals. This method requires no hardware modifications to both the normal radar transmitter and receiver and no change to the operating pulse repetition frequency (PRF). The distributed radar radiometric calibration and synchronization compensation require only one transponder, but the motion compensation requires six transponders because there are six independent variables in the distributed radar geometry. Furthermore, a maximum likelihood method is used to estimate the transponder signal parameters. The proposed methods are verified by simulation results. PMID:25794158

  13. Transponder-aided joint calibration and synchronization compensation for distributed radar systems.

    PubMed

    Wang, Wen-Qin

    2015-01-01

    High-precision radiometric calibration and synchronization compensation must be provided for distributed radar system due to separate transmitters and receivers. This paper proposes a transponder-aided joint radiometric calibration, motion compensation and synchronization for distributed radar remote sensing. As the transponder signal can be separated from the normal radar returns, it is used to calibrate the distributed radar for radiometry. Meanwhile, the distributed radar motion compensation and synchronization compensation algorithms are presented by utilizing the transponder signals. This method requires no hardware modifications to both the normal radar transmitter and receiver and no change to the operating pulse repetition frequency (PRF). The distributed radar radiometric calibration and synchronization compensation require only one transponder, but the motion compensation requires six transponders because there are six independent variables in the distributed radar geometry. Furthermore, a maximum likelihood method is used to estimate the transponder signal parameters. The proposed methods are verified by simulation results.

  14. Transponder-Aided Joint Calibration and Synchronization Compensation for Distributed Radar Systems

    PubMed Central

    Wang, Wen-Qin

    2015-01-01

    High-precision radiometric calibration and synchronization compensation must be provided for distributed radar system due to separate transmitters and receivers. This paper proposes a transponder-aided joint radiometric calibration, motion compensation and synchronization for distributed radar remote sensing. As the transponder signal can be separated from the normal radar returns, it is used to calibrate the distributed radar for radiometry. Meanwhile, the distributed radar motion compensation and synchronization compensation algorithms are presented by utilizing the transponder signals. This method requires no hardware modifications to both the normal radar transmitter and receiver and no change to the operating pulse repetition frequency (PRF). The distributed radar radiometric calibration and synchronization compensation require only one transponder, but the motion compensation requires six transponders because there are six independent variables in the distributed radar geometry. Furthermore, a maximum likelihood method is used to estimate the transponder signal parameters. The proposed methods are verified by simulation results. PMID:25794158

  15. Doppler radar results

    NASA Technical Reports Server (NTRS)

    Bracalente, Emedio M.

    1992-01-01

    The topics are covered in viewgraph form and include the following: (1) a summary of radar flight data collected; (2) a video of combined aft cockpit, nose camera, and radar hazard displays; (3) a comparison of airborne radar F-factor measurements with in situ and Terminal Doppler Weather Radar (TDWR) F-factors for some sample events; and (4) a summary of wind shear detection performance.

  16. System and method for measuring ocean surface currents at locations remote from land masses using synthetic aperture radar

    NASA Technical Reports Server (NTRS)

    Young, Lawrence E. (Inventor)

    1991-01-01

    A system for measuring ocean surface currents from an airborne platform is disclosed. A radar system having two spaced antennas wherein one antenna is driven and return signals from the ocean surface are detected by both antennas is employed to get raw ocean current data which are saved for later processing. There are a pair of global positioning system (GPS) systems including a first antenna carried by the platform at a first location and a second antenna carried by the platform at a second location displaced from the first antenna for determining the position of the antennas from signals from orbiting GPS navigational satellites. Data are also saved for later processing. The saved data are subsequently processed by a ground-based computer system to determine the position, orientation, and velocity of the platform as well as to derive measurements of currents on the ocean surface.

  17. Radar reflectivity

    NASA Astrophysics Data System (ADS)

    1986-07-01

    This TOP describes a method for measuring the radar reflectivity characteristics of aircraft. It uses a rotating platform and various radar systems to obtain calibrated radar Automatic Gain Control values for each degree of aspect angle for the aircraft. The purpose of this test is to provide comparable values of radar reflectivity for Army aircraft at various radar frequencies and parameter for fixed positions and aspect angles on the aircraft. Data collected on each specific aircraft can be used to evaluate radar reflectivity characteristics of aircraft skin material, paint, and structural changes such as flat versus curved surfaces.

  18. MST radar transmitter control and monitor system

    NASA Technical Reports Server (NTRS)

    Brosnahan, J. W.

    1983-01-01

    A generalized transmitter control and monitor card was developed using the Intel 8031 (8051 family) microprocessor. The design was generalized so that this card can be utilized for virtually any control application with only firmware changes. The block diagram appears in Figure 2. The card provides for local control using a 16 key keypad (up to 64 keys are supported). The local display is four digits of 7 segment LEDs. The display can indicate the status of all major system parameters and provide voltage readout for the analog signal inputs. The card can be populated with only the chips required for a given application. Fully populated, the card has two RS-232 serial ports for computer communications. It has a total of 48 TTL parallel lines that can define as either inputs or outputs in groups of four. A total of 32 analog inputs with a 0-5 volt range are supported. In addition, a real-time clock/calendar is available if required. A total of 16 k bytes of ROM and 16 k bytes of RAM is available for programming. This card can be the basis of virtually any monitor or control system with appropriate software.

  19. An expert system for shuttle and satellite radar tracker scheduling

    NASA Technical Reports Server (NTRS)

    Mitchell, Paul

    1988-01-01

    This expert system automates and optimizes radar tracker selection for shuttle missions. The expert system is written in the FORTRAN and C languages on an HP9000. It is portable to any UNIX machine having both ANSI-77 FORTRAN and C language compilers. It is a rule based expert system that selects tracking stations from the S-band and C-band radar stations and the TDRSS east and TDRSS west satellites under a variety of conditions. The expert system was prototyped on the Symbolics in the Automated Reasoning Tool (ART) and ZetaLisp. After the prototype demonstrated an acceptable automation of the process of selecting tracking stations to support the orbit determination requirements of Shuttle missions, the basic ART rules of the prototype were ported to the HP9000 computer using the CLIPS language. CLIPS is a forward-chaining rule-based expert system language written in C. Prior to the development of this expert system the selection process was a tedious manual process and expensive in terms of human resources. Manual tracking station selection required from 1 to 2 man weeks per mission; whereas the expert system can complete the selection process in about 2 hours.

  20. Airborne laser systems for atmospheric sounding in the near infrared

    NASA Astrophysics Data System (ADS)

    Sabatini, Roberto; Richardson, Mark A.; Jia, Huamin; Zammit-Mangion, David

    2012-06-01

    This paper presents new techniques for atmospheric sounding using Near Infrared (NIR) laser sources, direct detection electro-optics and passive infrared imaging systems. These techniques allow a direct determination of atmospheric extinction and, through the adoption of suitable inversion algorithms, the indirect measurement of some important natural and man-made atmospheric constituents, including Carbon Dioxide (CO2). The proposed techniques are suitable for remote sensing missions performed by using aircraft, satellites, Unmanned Aerial Vehicles (UAV), parachute/gliding vehicles, Roving Surface Vehicles (RSV), or Permanent Surface Installations (PSI). The various techniques proposed offer relative advantages in different scenarios. All are based on measurements of the laser energy/power incident on target surfaces of known geometric and reflective characteristics, by means of infrared detectors and/or infrared cameras calibrated for radiance. Experimental results are presented relative to ground and flight trials performed with laser systems operating in the near infrared (NIR) at λ = 1064 nm and λ = 1550 nm. This includes ground tests performed with 10 Hz and 20 KHz PRF NIR laser systems in a variety of atmospheric conditions, and flight trials performed with a 10 Hz airborne NIR laser system installed on a TORNADO aircraft, flying up to altitudes of 22,000 ft above ground level. Future activities are planned to validate the atmospheric retrieval algorithms developed for CO2 column density measurements, with emphasis on aircraft related emissions at airports and other high air-traffic density environments.

  1. A Bistatic Parasitical Radar (BIPAR)

    NASA Astrophysics Data System (ADS)

    Hartl, Philipp; Braun, Hans Martin

    1989-01-01

    After decades of remote sensing from aircraft and satellites with cameras and other optical sensors, earth observation by imaging radars becomes more and more suitable because of their night and day and all weather operations capability and their information content being complementary to those of optical sensors. The major problem with microwave sensors (radars) is that there are not enough of them presently in operation and therefore not enough data available for effective radar signature research for civil applications. It is shown that airborne bistatic real aperture radar receivers can be operated with spaceborne transmitters of opportunity. Famous candidates for those systems are high power communications or direct TV satellites illuminating the earth surface with a power denisty of more than 10(-12) Watt/sq meter. The high sophisticated status of signal processing technology today allows the realization of receivers correlating the received direct path signal from a communications satellite with its avoidable reflection on the ground. Coherent integration can improve the signal to noise ratio up to values where the radiometric resolution can satisfy users needs. The development of such parasitic radar receivers could even provide a cost effective way to open up new frequency bands for radar signature research. Advantages of these quiet systems for the purpose of classical radar reconnaissance are evident.

  2. Experimental 0.22 THz Stepped Frequency Radar System for ISAR Imaging

    NASA Astrophysics Data System (ADS)

    Liang, Mei Yan; Zhang, Cun Lin; Zhao, Ran; Zhao, Yue Jin

    2014-09-01

    High resolution inverse synthetic aperture radar (ISAR) imaging is demonstrated by using a 0.22 THz stepped-frequency (SF) imaging radar system. The synthesis bandwidth of the terahertz (THz) SF radar is 12 GHz, which are beneficial for high resolution imaging. The resolution of ISAR image can reach centimeter-scale with the use of Range-Doppler algorithm (RDA). Results indicate that high resolution ISAR imaging is realized by using 0.22THz SF radar coupled with turntable scanning, which can provide foundations for further research on high-resolution radar image in the THz band.

  3. Mapping tree root systems with ground-penetrating radar.

    PubMed

    Hruska, Jiri; Cermák, Jan; Sustek, Svatopluk

    1999-02-01

    A ground-penetrating radar (GPR) technique was used to study the three-dimensional distribution of root systems of large (DBH = 14 to 35 cm) oak trees (Quercus petraea (Mattusch.) Liebl.) in relatively dry, luvisoil on loamy deluvium and weathered granodiorite. We used a pulse EKKO 1000 GPR system, a profile grid of 0.25 x 0.25 meters, at 0.05 m intervals, and a signal frequency of 450 MHz, to assure resolution of about 3 cm in both directions (further increases in resolution up to 1 cm are possible with the system). Coarse root density was 6.5 m m(-2) of stand area and 3.3 m m(-3) of soil volume. Maximum rooting depth of the experimental oaks was 2 m, and the root ground plan was significantly larger (about 1.5 times) than the crown ground plan. Based on earlier studies of Quercus robur L. from floodplain forests, where the extent of the root systems was much smaller (root ground plan:crown ground plan ratio of 0.6), we conclude that the high root ground plan:crown ground plan ratio indicates less favorable conditions of water supply at the experimental site than in the floodplain forest. The ground-penetrating radar system is noninvasive and allows relatively rapid and repeated measurements of the distribution of coarse root systems of trees.

  4. Integrated radar-camera security system: experimental results

    NASA Astrophysics Data System (ADS)

    Zyczkowski, M.; Palka, N.; Trzcinski, T.; Dulski, R.; Kastek, M.; Trzaskawka, P.

    2011-06-01

    The nature of the recent military conflicts and terrorist attacks along with the necessity to protect bases, convoys and patrols have made a serious impact on the development of more effective security systems. Current widely-used perimeter protection systems with zone sensors will soon be replaced with multi-sensor systems. Multi-sensor systems can utilize day/night cameras, IR uncooled thermal cameras, and millimeter-wave radars which detect radiation reflected from targets. Ranges of detection, recognition and identification for all targets depend on the parameters of the sensors used and of the observed scene itself. In this paper two essential issues connected with multispectral systems are described. We will focus on describing the autonomous method of the system regarding object detection, tracking, identification, localization and alarm notifications. We will also present the possibility of configuring the system as a stationary, mobile or portable device as in our experimental results.

  5. Exposure to airborne particulate matter in the subway system.

    PubMed

    Martins, Vânia; Moreno, Teresa; Minguillón, María Cruz; Amato, Fulvio; de Miguel, Eladio; Capdevila, Marta; Querol, Xavier

    2015-04-01

    The Barcelona subway system comprises eight subway lines, at different depths, with different tunnel dimensions, station designs and train frequencies. An extensive measurement campaign was performed in this subway system in order to characterise the airborne particulate matter (PM) measuring its concentration and investigating its variability, both inside trains and on platforms, in two different seasonal periods (warmer and colder), to better understand the main factors controlling it, and therefore the way to improve air quality. The majority of PM in the underground stations is generated within the subway system, due to abrasion and wear of rail tracks, wheels and braking pads caused during the motion of the trains. Substantial variation in average PM concentrations between underground stations was observed, which might be associated to different ventilation and air conditioning systems, characteristics/design of each station and variations in the train frequency. Average PM2.5 concentrations on the platforms in the subway operating hours ranged from 20 to 51 and from 41 to 91 μg m(-3) in the warmer and colder period, respectively, mainly related to the seasonal changes in the subway ventilation systems. The new subway lines with platform screen doors showed PM2.5 concentrations lower than those in the conventional system, which is probably attributable not only to the more advanced ventilation setup, but also to the lower train frequency and the design of the stations. PM concentrations inside the trains were generally lower than those on the platforms, which is attributable to the air conditioning systems operating inside the trains, which are equipped with air filters. This study allows the analysis and quantification of the impact of different ventilation settings on air quality, which provides an improvement on the knowledge for the general understanding and good management of air quality in the subway system.

  6. Exposure to airborne particulate matter in the subway system.

    PubMed

    Martins, Vânia; Moreno, Teresa; Minguillón, María Cruz; Amato, Fulvio; de Miguel, Eladio; Capdevila, Marta; Querol, Xavier

    2015-04-01

    The Barcelona subway system comprises eight subway lines, at different depths, with different tunnel dimensions, station designs and train frequencies. An extensive measurement campaign was performed in this subway system in order to characterise the airborne particulate matter (PM) measuring its concentration and investigating its variability, both inside trains and on platforms, in two different seasonal periods (warmer and colder), to better understand the main factors controlling it, and therefore the way to improve air quality. The majority of PM in the underground stations is generated within the subway system, due to abrasion and wear of rail tracks, wheels and braking pads caused during the motion of the trains. Substantial variation in average PM concentrations between underground stations was observed, which might be associated to different ventilation and air conditioning systems, characteristics/design of each station and variations in the train frequency. Average PM2.5 concentrations on the platforms in the subway operating hours ranged from 20 to 51 and from 41 to 91 μg m(-3) in the warmer and colder period, respectively, mainly related to the seasonal changes in the subway ventilation systems. The new subway lines with platform screen doors showed PM2.5 concentrations lower than those in the conventional system, which is probably attributable not only to the more advanced ventilation setup, but also to the lower train frequency and the design of the stations. PM concentrations inside the trains were generally lower than those on the platforms, which is attributable to the air conditioning systems operating inside the trains, which are equipped with air filters. This study allows the analysis and quantification of the impact of different ventilation settings on air quality, which provides an improvement on the knowledge for the general understanding and good management of air quality in the subway system. PMID:25616190

  7. Multi-agent system for target-adaptive radar tracking

    NASA Astrophysics Data System (ADS)

    O'Connor, Alan C.

    2012-06-01

    Sensor systems such as distributed sensor networks and radar systems are potentially agile - they have parameters that can be adjusted in real-time to improve the quality of data obtained for state-estimation and decision-making. The integration of such sensors with cyber systems involving many users or agents permits greater flexibility in choosing measurement actions. This paper considers the problem of selecting radar waveforms to minimize uncertainty about the state of a tracked target. Past work gave a tractable method for optimizing the choice of measurements when an accurate dynamical model is available. However, prior knowledge about a system is often not precise, for example, if the target under observation is an adversary. A multiple agent system is proposed to solve the problem in the case of uncertain target dynamics. Each agent has a different target model and the agents compete to explain past data and select the parameters of future measurements. Collaboration or competition between these agents determines which obtains access to the limited physical sensing resources. This interaction produces a self-aware sensor that adapts to changing information requirements.

  8. Medium altitude airborne Geiger-mode mapping LIDAR system

    NASA Astrophysics Data System (ADS)

    Clifton, William E.; Steele, Bradley; Nelson, Graham; Truscott, Antony; Itzler, Mark; Entwistle, Mark

    2015-05-01

    Over the past 15 years the Massachusetts Institute of Technology, Lincoln Laboratory (MIT/LL), Defense Advanced Research Projects Agency (DARPA) and private industry have been developing airborne LiDAR systems based on arrays of Geiger-mode Avalanche Photodiode (GmAPD) detectors capable of detecting a single photon. The extreme sensitivity of GmAPD detectors allows operation of LiDAR sensors at unprecedented altitudes and area collection rates in excess of 1,000 km2/hr. Up until now the primary emphasis of this technology has been limited to defense applications despite the significant benefits of applying this technology to non-military uses such as mapping, monitoring critical infrastructure and disaster relief. This paper briefly describes the operation of GmAPDs, design and operation of a Geiger-mode LiDAR, a comparison of Geiger-mode and traditional linear mode LiDARs, and a description of the first commercial Geiger-mode LiDAR system, the IntelliEarth™ Geospatial Solutions Geiger-mode LiDAR sensor.

  9. Resolution analyses for selecting an appropriate airborne electromagnetic (AEM) system

    NASA Astrophysics Data System (ADS)

    Christensen, Niels B. 13Lawrie, Ken C.

    2012-07-01

    The choice of an appropriate airborne electromagnetic system for a given task should be based on a comparative analysis of candidate systems, consisting of both theoretical considerations and field studies including test lines. It has become common practice to quantify the system resolution for a series of models relevant to the survey area by comparing the sum over the data of squares of noise-normalised derivatives. We compare this analysis method with a resolution analysis based on the posterior covariance matrix of an inversion formulation. Both of the above analyses depend critically on the noise models of the systems being compared. A reasonable estimate of data noise and other sources of error is therefore of primary importance. However, data processing and noise reduction procedures, as well as other system parameters important for the modelling, are commonly proprietary, and generally it is not possible to verify whether noise figures have been arrived at by reasonable means. Consequently, it is difficult - sometimes impossible - to know if a comparative analysis has a sound basis. Nevertheless, in the real world choices have to be made, a comparative system analysis is necessary and has to be approached in a pragmatic way involving a range of different aspects. In this paper, we concentrate on the resolution analysis perspective and demonstrate that the inversion analysis must be preferred over the derivative analysis because it takes parameter coupling into account, and, furthermore, that the derivative analysis generally overestimates the resolution capability. Finally we show that impulse response data are to be preferred over step response data for near-surface resolution.

  10. Analysis of chaotic FM system synchronization for bistatic radar

    NASA Astrophysics Data System (ADS)

    Pappu, Chandra S.; Verdin, Berenice; Flores, Benjamin C.; Boehm, James; Debroux, Patrick

    2015-05-01

    We propose a scheme for bistatic radar that uses a chaotic system to generate a wideband FM signal that is reconstructed at the receiver via a conventional phase lock loop. The setup for the bistatic radar includes a 3 state variable drive oscillator at the transmitter and a response oscillator at the receiver. The challenge is in synchronizing the response oscillator of the radar receiver utilizing a scaled version of the transmitted signal sr(t, x) = αst(t, x) where x is one of three driver oscillator state variables and α is the scaling factor that accounts for antenna gain, system losses, and space propagation. For FM, we also assume that the instantaneous frequency of the received signal, xs, is a scaled version of the Lorenz variable x. Since this additional scaling factor may not be known a priori, the response oscillator must be able to accept the scaled version of x as an input. Thus, to achieve synchronization we utilize a generalized projective synchronization technique that introduces a controller term -μe where μ is a control factor and e is the difference between the response state variable xs and a scaled x. Since demodulation of sr(t) is required to reconstruct the chaotic state variable x, the phase lock loop imposes a limit on the minimum error e. We verify through simulations that, once synchronization is achieved, the short-time correlation of x and xs is high and that the self-noise in the correlation is negligible over long periods of time.

  11. First Results from an Airborne Ka-Band SAR Using SweepSAR and Digital Beamforming

    NASA Technical Reports Server (NTRS)

    Sadowy, Gregory A.; Ghaemi, Hirad; Hensley, Scott C.

    2012-01-01

    SweepSAR is a wide-swath synthetic aperture radar technique that is being studied for application on the future Earth science radar missions. This paper describes the design of an airborne radar demonstration that simulates an 11-m L-band (1.2-1.3 GHz) reflector geometry at Ka-band (35.6 GHz) using a 40-cm reflector. The Ka-band SweepSAR Demonstration system was flown on the NASA DC-8 airborne laboratory and used to study engineering performance trades and array calibration for SweepSAR configurations. We present an instrument and experiment overview, instrument calibration and first results.

  12. Next-Generation NASA Airborne Oceanographic Lidar System.

    PubMed

    Wright, C W; Hoge, F E; Swift, R N; Yungel, J K; Schirtzinger, C R

    2001-01-20

    The complete design and flight test of the next-generation Airborne Oceanographic Lidar (AOL-3) is detailed. The application of new technology has allowed major reductions in weight, volume, and power requirements compared with the earlier AOL sensor. Subsystem designs for the new AOL sensor include new technology in fiber optics, spectrometer detector optical train, miniature photomultiplier modules, dual-laser wavelength excitation from a single small laser source, and new receiver optical configuration. The new design reduced telescope size and maintained the same principal fluorescence and water Raman bands but essentially retained a comparable measurement accuracy. A major advancement is the implementation of single-laser simultaneous excitation of two physically separate oceanic target areas: one stimulated by 532 nm and the other by 355 nm. Backscattered fluorescence and Raman signals from both targets are acquired simultaneously by use of the same telescope and spectrometer-detector system. Two digital oscilloscopes provide temporal- and depth-resolved data from each of seven spectral emission bands.

  13. Airborne laser ranging system for monitoring regional crustal deformation

    NASA Technical Reports Server (NTRS)

    Degnan, J. J.

    1981-01-01

    Alternate approaches for making the atmospheric correction without benefit of a ground-based meteorological network are discussed. These include (1) a two-color channel that determines the atmospheric correction by measuring the time delay induced by dispersion between pulses at two optical frequencies; (2) single-color range measurements supported by an onboard temperature sounder, pressure altimeter readings, and surface measurements by a few existing meteorological facilities; and (3) inclusion of the quadratic polynomial coefficients as variables to be solved for along with target coordinates in the reduction of the single-color range data. It is anticipated that the initial Airborne Laser Ranging System (ALRS) experiments will be carried out in Southern California in a region bounded by Santa Barbara on the norht and the Mexican border on the south. The target area will be bounded by the Pacific Ocean to the west and will extend eastward for approximately 400 km. The unique ability of the ALRS to provide a geodetic 'snapshot' of such a large area will make it a valuable geophysical tool.

  14. Development of radar cross section analysis system of naval ships

    NASA Astrophysics Data System (ADS)

    Kim, Kookhyun; Kim, Jin-Hyeong; Choi, Tae-Muk; Cho, Dae-Seung

    2012-03-01

    A software system for a complex object scattering analysis, named SYSCOS, has been developed for a systematic radar cross section (RCS) analysis and reduction design. The system is based on the high frequency analysis methods of physical optics, geometrical optics, and physical theory of diffraction, which are suitable for RCS analysis of electromagnetically large and complex targets as like naval ships. In addition, a direct scattering center analysis function has been included, which gives relatively simple and intuitive way to discriminate problem areas in design stage when comparing with conventional image-based approaches. In this paper, the theoretical background and the organization of the SYSCOS system are presented. To verify its accuracy and to demonstrate its applicability, numerical analyses for a square plate, a sphere and a cylinder, a weapon system and a virtual naval ship have been carried out, of which results have been compared with analytic solutions and those obtained by the other existing software.

  15. Fiber optic coherent laser radar 3D vision system

    SciTech Connect

    Clark, R.B.; Gallman, P.G.; Slotwinski, A.R.; Wagner, K.; Weaver, S.; Xu, Jieping

    1996-12-31

    This CLVS will provide a substantial advance in high speed computer vision performance to support robotic Environmental Management (EM) operations. This 3D system employs a compact fiber optic based scanner and operator at a 128 x 128 pixel frame at one frame per second with a range resolution of 1 mm over its 1.5 meter working range. Using acousto-optic deflectors, the scanner is completely randomly addressable. This can provide live 3D monitoring for situations where it is necessary to update once per second. This can be used for decontamination and decommissioning operations in which robotic systems are altering the scene such as in waste removal, surface scarafacing, or equipment disassembly and removal. The fiber- optic coherent laser radar based system is immune to variations in lighting, color, or surface shading, which have plagued the reliability of existing 3D vision systems, while providing substantially superior range resolution.

  16. A radome for air traffic control SSR radar systems

    NASA Astrophysics Data System (ADS)

    A new generation of monopulse and discrete interrogation systems has evolved for air traffic control applications that presents significant challenges to total system design and performance. Reliable operation of the antenna system is essential in today's ever increasing air traffic congestion. An important component of the total system is a radome to protect the antenna from the environment and to enable consistent, reliable electromagnetic performance. The various types of radomes that have been employed over the years to protect antennas are discussed and evaluated relative to the air traffic control radar application. The sandwich radome is selected as the best option and a detailed design analysis is presented which considers the vital characteristics of transmissivity, boresight error, and sidelobe perturbations.

  17. A novel ultra-wideband 80 GHz FMCW radar system for contactless monitoring of vital signs.

    PubMed

    Wang, Siying; Pohl, Antje; Jaeschke, Timo; Czaplik, Michael; Köny, Marcus; Leonhardt, Steffen; Pohl, Nils

    2015-01-01

    In this paper an ultra-wideband 80 GHz FMCW-radar system for contactless monitoring of respiration and heart rate is investigated and compared to a standard monitoring system with ECG and CO(2) measurements as reference. The novel FMCW-radar enables the detection of the physiological displacement of the skin surface with submillimeter accuracy. This high accuracy is achieved with a large bandwidth of 10 GHz and the combination of intermediate frequency and phase evaluation. This concept is validated with a radar system simulation and experimental measurements are performed with different radar sensor positions and orientations.

  18. A novel ultra-wideband 80 GHz FMCW radar system for contactless monitoring of vital signs.

    PubMed

    Wang, Siying; Pohl, Antje; Jaeschke, Timo; Czaplik, Michael; Köny, Marcus; Leonhardt, Steffen; Pohl, Nils

    2015-01-01

    In this paper an ultra-wideband 80 GHz FMCW-radar system for contactless monitoring of respiration and heart rate is investigated and compared to a standard monitoring system with ECG and CO(2) measurements as reference. The novel FMCW-radar enables the detection of the physiological displacement of the skin surface with submillimeter accuracy. This high accuracy is achieved with a large bandwidth of 10 GHz and the combination of intermediate frequency and phase evaluation. This concept is validated with a radar system simulation and experimental measurements are performed with different radar sensor positions and orientations. PMID:26737409

  19. Three-dimensional radar imaging techniques and systems for near-field applications

    NASA Astrophysics Data System (ADS)

    Sheen, David M.; Hall, Thomas E.; McMakin, Douglas L.; Jones, A. Mark; Tedeschi, Jonathan R.

    2016-05-01

    The Pacific Northwest National Laboratory has developed three-dimensional holographic (synthetic aperture) radar imaging techniques and systems for a wide variety of near-field applications. These applications include radar crosssection (RCS) imaging, personnel screening, standoff concealed weapon detection, concealed threat detection, throughbarrier imaging, ground penetrating radar (GPR), and non-destructive evaluation (NDE). Sequentially-switched linear arrays are used for many of these systems to enable high-speed data acquisition and 3-D imaging. In this paper, the techniques and systems will be described along with imaging results that demonstrate the utility of near-field 3-D radar imaging for these compelling applications.

  20. Flood disaster monitoring in Thailand by using a airborne L-band SAR: Polarimetric and interferometry Synthetic Aperture Radar with L-band(Pi-SAR-L)

    NASA Astrophysics Data System (ADS)

    Kawano, N.; Sobue, S.; Shimada, M.; Ohyoshi, K.

    2012-04-01

    It was heavy rainfall around the northern region of Thailand from July to September 2011, which caused flood disaster to quite wide region of Thailand, it finally reached to the Bangkok central in the end of October 2011. Japan Aerospace Exploration Agency (JAXA) conducted an emergency observation by using a airborne L-band SAR: Polarimetric and interferometry Synthetic Aperture Radar with L-band(Pi-SAR-L) from 5th to 27th November to monitor flood area. Pi-SAR-L has a center frequency of 1271.5 MHz, a band width of 50 MHz, a slant range resolution of 3 m, and an acquisition swath of 15 km on the ground. Pi-SAR-L is boarded on an aircraft of the Gulfstream-II operated by the Diamond Air Service(DAS), Japan, and the Gulfstream-II was ferried to the Chieng-Mai airport in the North Thailand, from Japan. In our presentation, we will show flood area around Bangkok and its variations detected by Pi-SAR-L

  1. Maximum-likelihood spectral estimation and adaptive filtering techniques with application to airborne Doppler weather radar. Thesis Technical Report No. 20

    NASA Technical Reports Server (NTRS)

    Lai, Jonathan Y.

    1994-01-01

    This dissertation focuses on the signal processing problems associated with the detection of hazardous windshears using airborne Doppler radar when weak weather returns are in the presence of strong clutter returns. In light of the frequent inadequacy of spectral-processing oriented clutter suppression methods, we model a clutter signal as multiple sinusoids plus Gaussian noise, and propose adaptive filtering approaches that better capture the temporal characteristics of the signal process. This idea leads to two research topics in signal processing: (1) signal modeling and parameter estimation, and (2) adaptive filtering in this particular signal environment. A high-resolution, low SNR threshold maximum likelihood (ML) frequency estimation and signal modeling algorithm is devised and proves capable of delineating both the spectral and temporal nature of the clutter return. Furthermore, the Least Mean Square (LMS) -based adaptive filter's performance for the proposed signal model is investigated, and promising simulation results have testified to its potential for clutter rejection leading to more accurate estimation of windspeed thus obtaining a better assessment of the windshear hazard.

  2. Joint Variability of Airborne Passive Microwave and Ground-based Radar Observations Obtained in the TRMM Kwajalein Experiment

    NASA Astrophysics Data System (ADS)

    Yuter, S. E.; Kingsmill, D. E.

    2007-12-01

    The Tropical Rainfall Measuring Mission (TRMM) Kwajalein Experiment (KWAJEX) held July-September 1999 in the west Pacific was designed to obtain an empirical physical characterization of precipitating convective clouds over the tropical ocean. The majority of the precipitation was from mixed-phase clouds. Coordinated data sets were obtained from aircraft and ground-based sensors including passive microwave measurements by the Advanced Microwave Precipitation Radiometer (AMPR) instrument on the NASA DC-8 aircraft and S-band volumetric radar data by the KPOL radar. The AMPR and KPOL data sets were processed to yield a set of 25,049 matching observations at ~ 2 km x 2 km horizontal spatial resolution and within 6 min. The TRMM satellite Microwave Imager (TMI) has a similar set of channels to AMPR but coarser spatial resolution (19 GHz: 35 km, 85 GHz: 7.7 km). During KWAJEX, the 0 deg C level height was nearly constant at ~ 4800 m. Hence, two potential sources of uncertainty in relating passive microwave brightness temperatures (Tbs) to surface precipitation, inhomogeneous beam filling and variations in depth of the rain layer are much smaller sources of error in the KWAJEX data set than for TMI. TRMM was originally designed to yield monthly rainfall estimates over 5 deg x 5 deg grid boxes. The use of these data to yield instantaneous rainrate products at smaller spatial scales is more sensitive to the detailed characteristics of the joint distributions of passive microwave Tbs versus rain rate. KWAJEX data sets reveal poor correlations, very wide scatter, and weak modes in these distributions. The spread of emission Tb values for a given rain-layer reflectivity (e.g., 75 K at 30 dBZ for 19 GHz) is similar or larger within convective compared to stratiform precipitation regions. This result implies that the enhancement in emission Tbs associated with partially melted ice particles can occur whether the particles are concentrated within a thin layer in stratiform

  3. The Goldstone solar system radar: A science instrument for planetary research

    NASA Technical Reports Server (NTRS)

    Dvorsky, J. D.; Renzetti, N. A.; Fulton, D. E.

    1992-01-01

    The Goldstone Solar System Radar (GSSR) station at NASA's Deep Space Communications Complex in California's Mojave Desert is described. A short chronological account of the GSSR's technical development and scientific discoveries is given. This is followed by a basic discussion of how information is derived from the radar echo and how the raw information can be used to increase understanding of the solar system. A moderately detailed description of the radar system is given, and the engineering performance of the radar is discussed. The operating characteristics of the Arcibo Observatory in Puerto Rico are briefly described and compared with those of the GSSR. Planned and in-process improvements to the existing radar, as well as the performance of a hypothetical 128-m diameter antenna radar station, are described. A comprehensive bibliography of referred scientific and engineering articles presenting results that depended on data gathered by the instrument is provided.

  4. 47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Technical requirements for ground penetrating radars and wall imaging systems. 15.509 Section 15.509 Telecommunication FEDERAL COMMUNICATIONS... ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of an imaging system...

  5. 47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Technical requirements for ground penetrating radars and wall imaging systems. 15.509 Section 15.509 Telecommunication FEDERAL COMMUNICATIONS... ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of an imaging system...

  6. 47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Technical requirements for ground penetrating radars and wall imaging systems. 15.509 Section 15.509 Telecommunication FEDERAL COMMUNICATIONS... ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of an imaging system...

  7. 47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Technical requirements for ground penetrating radars and wall imaging systems. 15.509 Section 15.509 Telecommunication FEDERAL COMMUNICATIONS... ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of an imaging system...

  8. 47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Technical requirements for ground penetrating radars and wall imaging systems. 15.509 Section 15.509 Telecommunication FEDERAL COMMUNICATIONS... ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of an imaging system...

  9. A Portable Low-Power Harmonic Radar System and Conformal Tag for Insect Tracking

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Harmonic radar systems provide an effective modality for tracking insect behavior. This paper presents a harmonic radar system proposed to track the migration of the Emerald Ash Borer (EAB). The system offers a unique combination of portability, low power and small tag design. It is comprised of a...

  10. Antarctica X-band MiniSAR crevasse detection radar : final report.

    SciTech Connect

    Sander, Grant J.; Bickel, Douglas Lloyd

    2007-09-01

    This document is the final report for the Antarctica Synthetic Aperture Radar (SAR) Project. The project involved the modification of a Sandia National Laboratories MiniSAR system to operate at X-band in order to assess the feasibility of an airborne radar to detect crevasses in Antarctica. This radar successfully detected known crevasses at various geometries. The best results were obtained for synthetic aperture radar resolutions of at most one foot and finer. In addition to the main goal of detecting crevasses, the radar was used to assess conops for a future operational radar. The radar scanned large areas to identify potential safe landing zones. In addition, the radar was used to investigate looking at objects on the surface and below the surface of the ice. This document includes discussion of the hardware development, system capabilities, and results from data collections in Antarctica.

  11. SYSIPHE system: a state of the art airborne hyperspectral imaging system: initial results from the first airborne campaign

    NASA Astrophysics Data System (ADS)

    Rousset-Rouviere, Laurent; Coudrain, Christophe; Fabre, Sophie; Poutier, Laurent; Løke, Trond; Fridman, Andrei; Blaaberg, Søren; Baarstad, Ivar; Skauli, Torbjorn; Mocoeur, Isabelle

    2014-10-01

    SYSIPHE is an airborne hyperspectral imaging system, result of a cooperation between France (Onera and DGA) and Norway (NEO and FFI). It is a unique system by its spatial sampling -0.5m with a 500m swath at a ground height of 2000m- combined with its wide spectral coverage -from 0.4μm to 11.5μm in the atmospheric transmission bands. Its infrared component, named SIELETERS, consists in two high étendue imaging static Fourier transform spectrometers, one for the midwave infrared and one for the longwave infrared. These two imaging spectrometers are closely similar in design, since both are made of a Michelson interferometer, a refractive imaging system, and a large IRFPA (1016x440 pixels). Moreover, both are cryogenically cooled and mounted on their own stabilization platform which allows the line of sight to be controlled and recorded. These data are useful to reconstruct and to georeference the spectral image from the raw interferometric images. The visible and shortwave infrared component, named Hyspex ODIN-1024, consists of two spectrographs for VNIR and SWIR based on transmissive gratings. These share a common fore-optics and a common slit, to ensure perfect registration between the VNIR and the SWIR images. The spectral resolution varies from 5nm in the visible to 6nm in the shortwave infrared. In addition, the STAD, the post processing and archiving system, is developed to provide spectral reflectance and temperature products (SRT products) from calibrated georeferenced and inter-band registered spectral images at the sensor level acquired and pre-processed by SIELETERS and Hyspex ODIN-1024 systems.

  12. A novel backpackable ice-penetrating radar system

    NASA Astrophysics Data System (ADS)

    Matsuoka, Kenichi; Saito, Ryoji; Naruse, Renji

    We have developed a novel ice-penetrating radar system that can be carried on a backpack. Including batteries for a 3 hour continuous measurement, the total weight is 13 kg. In addition, it operates reliably down to -25°C, has a low power consumption of 24 W, and is semi-waterproof. The system has a built-in-one controller with a high-brightness display for reading data quickly, a receiver with 12-bit digitizing, and a 1 kV pulse transmitter in which the pulse amplitude varies by <0.2%. Optical communications between components provides low-noise data acquisition and allows synchronizing of the pulse transmission with sampling. Measurements with the system revealed the 300 m deep bed topography of a temperate valley glacier in the late ablation season.

  13. Airborne Asbestos Exposures from Warm Air Heating Systems in Schools.

    PubMed

    Burdett, Garry J; Dewberry, Kirsty; Staff, James

    2016-01-01

    The aim of this study was to investigate the concentrations of airborne asbestos that can be released into classrooms of schools that have amosite-containing asbestos insulation board (AIB) in the ceiling plenum or other spaces, particularly where there is forced recirculation of air as part of a warm air heating system. Air samples were collected in three or more classrooms at each of three schools, two of which were of CLASP (Consortium of Local Authorities Special Programme) system-built design, during periods when the schools were unoccupied. Two conditions were sampled: (i) the start-up and running of the heating systems with no disturbance (the background) and (ii) running of the heating systems during simulated disturbance. The simulated disturbance was designed to exceed the level of disturbance to the AIB that would routinely take place in an occupied classroom. A total of 60 or more direct impacts that vibrated and/or flexed the encapsulated or enclosed AIB materials were applied over the sampling period. The impacts were carried out at the start of the sampling and repeated at hourly intervals but did not break or damage the AIB. The target air volume for background samples was ~3000 l of air using a static sampler sited either below or ~1 m from the heater outlet. This would allow an analytical sensitivity (AS) of 0.0001 fibres per millilitre (f ml(-1)) to be achieved, which is 1000 times lower than the EU and UK workplace control limit of 0.1 f ml(-1). Samples with lower volumes of air were also collected in case of overloading and for the shorter disturbance sampling times used at one site. The sampler filters were analysed by phase contrast microscopy (PCM) to give a rapid determination of the overall concentration of visible fibres (all types) released and/or by analytical transmission electron microscopy (TEM) to determine the concentration of asbestos fibres. Due to the low number of fibres, results were reported in terms of both the calculated

  14. Airborne Asbestos Exposures from Warm Air Heating Systems in Schools

    PubMed Central

    Burdett, Garry J.; Dewberry, Kirsty; Staff, James

    2016-01-01

    The aim of this study was to investigate the concentrations of airborne asbestos that can be released into classrooms of schools that have amosite-containing asbestos insulation board (AIB) in the ceiling plenum or other spaces, particularly where there is forced recirculation of air as part of a warm air heating system. Air samples were collected in three or more classrooms at each of three schools, two of which were of CLASP (Consortium of Local Authorities Special Programme) system-built design, during periods when the schools were unoccupied. Two conditions were sampled: (i) the start-up and running of the heating systems with no disturbance (the background) and (ii) running of the heating systems during simulated disturbance. The simulated disturbance was designed to exceed the level of disturbance to the AIB that would routinely take place in an occupied classroom. A total of 60 or more direct impacts that vibrated and/or flexed the encapsulated or enclosed AIB materials were applied over the sampling period. The impacts were carried out at the start of the sampling and repeated at hourly intervals but did not break or damage the AIB. The target air volume for background samples was ~3000 l of air using a static sampler sited either below or ~1 m from the heater outlet. This would allow an analytical sensitivity (AS) of 0.0001 fibres per millilitre (f ml−1) to be achieved, which is 1000 times lower than the EU and UK workplace control limit of 0.1 f ml−1. Samples with lower volumes of air were also collected in case of overloading and for the shorter disturbance sampling times used at one site. The sampler filters were analysed by phase contrast microscopy (PCM) to give a rapid determination of the overall concentration of visible fibres (all types) released and/or by analytical transmission electron microscopy (TEM) to determine the concentration of asbestos fibres. Due to the low number of fibres, results were reported in terms of both the calculated

  15. Optimal waveforms for MIMO radar systems employing the generalized detector

    NASA Astrophysics Data System (ADS)

    Tuzlukov, Vyacheslav

    2010-04-01

    We consider the problem of waveform design for multiple-input multiple-output (MIMO) radar systems employing the generalized detector that is constructed based on the generalized approach to signal processing in noise. We investigate the case of an extended target and without limiting ourselves to orthogonal waveforms. Instead, we develop a procedure to design the optimal waveform that maximizes the signal-to-interference plus-noise ratio (SINR) at the generalized detector output. The optimal waveform requires a knowledge of both target and clutter statistics. We also develop several suboptimal waveforms requiring knowledge of target statistics only, clutter statistics only, or both. Thus, the transmit waveforms are adjusted based on target and clutter statistics. A model for the radar returns that incorporates the transmit waveforms is developed. The target detection problem is formulated for that model. Optimal and suboptimal algorithms are derived for designing the transmit waveforms under different assumptions regarding the statistical information available to the generalized detector. The performance of these algorithms is illustrated by computer simulation.

  16. Rapid System to Quantitatively Characterize the Airborne Microbial Community

    NASA Technical Reports Server (NTRS)

    Macnaughton, Sarah J.

    1998-01-01

    Bioaerosols have been linked to a wide range of different allergies and respiratory illnesses. Currently, microorganism culture is the most commonly used method for exposure assessment. Such culture techniques, however, generally fail to detect between 90-99% of the actual viable biomass. Consequently, an unbiased technique for detecting airborne microorganisms is essential. In this Phase II proposal, a portable air sampling device his been developed for the collection of airborne microbial biomass from indoor (and outdoor) environments. Methods were evaluated for extracting and identifying lipids that provide information on indoor air microbial biomass, and automation of these procedures was investigated. Also, techniques to automate the extraction of DNA were explored.

  17. Airborne radar evidence for tributary flow switching in Institute Ice Stream, West Antarctica: Implications for ice sheet configuration and dynamics

    NASA Astrophysics Data System (ADS)

    Winter, Kate; Woodward, John; Ross, Neil; Dunning, Stuart A.; Bingham, Robert G.; Corr, Hugh F. J.; Siegert, Martin J.

    2015-09-01

    Despite the importance of ice streaming to the evaluation of West Antarctic Ice Sheet (WAIS) stability we know little about mid- to long-term dynamic changes within the Institute Ice Stream (IIS) catchment. Here we use airborne radio echo sounding to investigate the subglacial topography, internal stratigraphy, and Holocene flow regime of the upper IIS catchment near the Ellsworth Mountains. Internal layer buckling within three discrete, topographically confined tributaries, through Ellsworth, Independence, and Horseshoe Valley Troughs, provides evidence for former enhanced ice sheet flow. We suggest that enhanced ice flow through Independence and Ellsworth Troughs, during the mid-Holocene to late Holocene, was the source of ice streaming over the region now occupied by the slow-flowing Bungenstock Ice Rise. Although buckled layers also exist within the slow-flowing ice of Horseshoe Valley Trough, a thicker sequence of surface-conformable layers in the upper ice column suggests slowdown more than ~4000 years ago, so we do not attribute enhanced flow switch-off here, to the late Holocene ice-flow reorganization. Intensely buckled englacial layers within Horseshoe Valley and Independence Troughs cannot be accounted for under present-day flow speeds. The dynamic nature of ice flow in IIS and its tributaries suggests that recent ice stream switching and mass changes in the Siple Coast and Amundsen Sea sectors are not unique to these sectors, that they may have been regular during the Holocene and may characterize the decline of the WAIS.

  18. Photoelectric radar servo control system based on ARM+FPGA

    NASA Astrophysics Data System (ADS)

    Wu, Kaixuan; Zhang, Yue; Li, Yeqiu; Dai, Qin; Yao, Jun

    2016-01-01

    In order to get smaller, faster, and more responsive requirements of the photoelectric radar servo control system. We propose a set of core ARM + FPGA architecture servo controller. Parallel processing capability of FPGA to be used for the encoder feedback data, PWM carrier modulation, A, B code decoding processing and so on; Utilizing the advantage of imaging design in ARM Embedded systems achieves high-speed implementation of the PID algorithm. After the actual experiment, the closed-loop speed of response of the system cycles up to 2000 times/s, in the case of excellent precision turntable shaft, using a PID algorithm to achieve the servo position control with the accuracy of + -1 encoder input code. Firstly, This article carry on in-depth study of the embedded servo control system hardware to determine the ARM and FPGA chip as the main chip with systems based on a pre-measured target required to achieve performance requirements, this article based on ARM chip used Samsung S3C2440 chip of ARM7 architecture , the FPGA chip is chosen xilinx's XC3S400 . ARM and FPGA communicate by using SPI bus, the advantage of using SPI bus is saving a lot of pins for easy system upgrades required thereafter. The system gets the speed datas through the photoelectric-encoder that transports the datas to the FPGA, Then the system transmits the datas through the FPGA to ARM, transforms speed datas into the corresponding position and velocity data in a timely manner, prepares the corresponding PWM wave to control motor rotation by making comparison between the position data and the velocity data setted in advance . According to the system requirements to draw the schematics of the photoelectric radar servo control system and PCB board to produce specially. Secondly, using PID algorithm to control the servo system, the datas of speed obtained from photoelectric-encoder is calculated position data and speed data via high-speed digital PID algorithm and coordinate models. Finally, a

  19. Small battery operated unattended radar sensor for security systems

    NASA Astrophysics Data System (ADS)

    Plummer, Thomas J.; Brady, Stephen; Raines, Robert

    2013-06-01

    McQ has developed, tested, and is supplying to Unattended Ground Sensor (UGS) customers a new radar sensor. This radar sensor is designed for short range target detection and classification. The design emphasis was to have low power consumption, totally automated operation, a very high probability of detection coupled with a very low false alarm rate, be able to locate and track targets, and have a price compatible with the UGS market. The radar sensor complements traditional UGS sensors by providing solutions for scenarios that are difficult for UGS. The design of this radar sensor and the testing are presented in this paper.

  20. Auxiliary signal processing system for a multiparameter radar

    NASA Technical Reports Server (NTRS)

    Chandrasekar, V.; Gray, G. R.; Caylor, I. J.

    1993-01-01

    The design of an auxiliary signal processor for a multiparameter radar is described with emphasis on low cost, quick development, and minimum disruption of radar operations. The processor is based around a low-cost digital signal processor card and personal computer controller. With the use of such a concept, an auxiliary processor was implemented for the NCAR CP-2 radar during a 1991 summer field campaign and allowed measurement of additional polarimetric parameters, namely, the differential phase and the copolar cross correlation. Sample data are presented from both the auxiliary and existing radar signal processors.

  1. A Wing Pod-based Millimeter Wave Cloud Radar on HIAPER

    NASA Astrophysics Data System (ADS)

    Vivekanandan, Jothiram; Tsai, Peisang; Ellis, Scott; Loew, Eric; Lee, Wen-Chau; Emmett, Joanthan

    2014-05-01

    One of the attractive features of a millimeter wave radar system is its ability to detect micron-sized particles that constitute clouds with lower than 0.1 g m-3 liquid or ice water content. Scanning or vertically-pointing ground-based millimeter wavelength radars are used to study stratocumulus (Vali et al. 1998; Kollias and Albrecht 2000) and fair-weather cumulus (Kollias et al. 2001). Airborne millimeter wavelength radars have been used for atmospheric remote sensing since the early 1990s (Pazmany et al. 1995). Airborne millimeter wavelength radar systems, such as the University of Wyoming King Air Cloud Radar (WCR) and the NASA ER-2 Cloud Radar System (CRS), have added mobility to observe clouds in remote regions and over oceans. Scientific requirements of millimeter wavelength radar are mainly driven by climate and cloud initiation studies. Survey results from the cloud radar user community indicated a common preference for a narrow beam W-band radar with polarimetric and Doppler capabilities for airborne remote sensing of clouds. For detecting small amounts of liquid and ice, it is desired to have -30 dBZ sensitivity at a 10 km range. Additional desired capabilities included a second wavelength and/or dual-Doppler winds. Modern radar technology offers various options (e.g., dual-polarization and dual-wavelength). Even though a basic fixed beam Doppler radar system with a sensitivity of -30 dBZ at 10 km is capable of satisfying cloud detection requirements, the above-mentioned additional options, namely dual-wavelength, and dual-polarization, significantly extend the measurement capabilities to further reduce any uncertainty in radar-based retrievals of cloud properties. This paper describes a novel, airborne pod-based millimeter wave radar, preliminary radar measurements and corresponding derived scientific products. Since some of the primary engineering requirements of this millimeter wave radar are that it should be deployable on an airborne platform

  2. Airborne laser scan measurements of winter snow accumulation in high alpine catchments - hydrological implications and verification by ground penetrating radar at glacier surface

    NASA Astrophysics Data System (ADS)

    Helfricht, K.; Keuschnig, M.; Heilig, A.; Mayer, C.; Kuhn, M.

    2012-04-01

    The snow cover as storage of winter precipitation is a substantial source for runoff generation in high mountain catchments. Redistribution of solid precipitation, caused by wind and gravity, leads to a characteristic spatial distribution of snow accumulation which differs from simple model assumption of a homogenous snowpack increasing with altitude. Both, the distinct distribution of snow accumulation and the total amount of SWE stored in the snow cover, affect the magnitude and seasonality of melt water runoff. Complex relations exist between the spatial pattern of snow accumulation and the presence of glaciers and vice versa. For proper hydrological modeling in high mountain catchments, knowledge about snow cover distribution is an important requirement. To date, to evaluate modeling results, spatially insufficient point data on snow depths and SWE are usually available. On catchment scale, optical space-borne remote sensing techniques deliver areal extent of snow cover, but no snow depths and hence no volume of snow cover. Multi-temporal airborne laser scanning (ALS) is an active remote sensing method to obtain elevation changes extensively even in inaccessible alpine terrain. Before the start and at the end of accumulation season of winter 2010/2011, two airborne laser scan acquisitions were performed in the Ötztal Alps (Tirol, Austria). Differences of the respective digital elevation models were interpreted as snow depths and converted into SWE using a simple regression method between snow depths and snow density. Preferred snow accumulation areas were determined, e.g. wind sheltered depressions, the base of steep mountain walls and flat glacier surfaces. At catchment scale, solid precipitation is obviously redistributed from wind exposed mountain ridges to lower elevations, inducing characteristic elevations of maximum snow accumulation. Overall, catchment precipitation derived from snow accumulation is a valuable reference for precipitation approaches in

  3. Buried mine detection using ground-penetrating impulse radar

    SciTech Connect

    Sargis, P.D.

    1995-03-01

    LLNL is developing a side-looking, ground-penetrating impulse radar system that can eventually be mounted on a robotic vehicle or an airborne platform to locate buried land mines. The system is described and results from field experiments are presented.

  4. Airborne Microwave Imaging of River Velocities

    NASA Technical Reports Server (NTRS)

    Plant, William J.

    2002-01-01

    The objective of this project was to determine whether airborne microwave remote sensing systems can measure river surface currents with sufficient accuracy to make them prospective instruments with which to monitor river flow from space. The approach was to fly a coherent airborne microwave Doppler radar, developed by APL/UW, on a light airplane along several rivers in western Washington state over an extended period of time. The fundamental quantity obtained by this system to measure river currents is the mean offset of the Doppler spectrum. Since this scatter can be obtained from interferometric synthetic aperture radars (INSARs), which can be flown in space, this project provided a cost effective means for determining the suitability of spaceborne INSAR for measuring river flow.

  5. Planetary Geology with Imaging Radar: Insights from Earth-based Lunar Studies, 2001-2015

    NASA Astrophysics Data System (ADS)

    Campbell, Bruce A.

    2016-06-01

    Radar exploration of the Solar System changed dramatically during and beyond the period of the Magellan mission to Venus. These changes included an expansion of the community familiar with microwave data, and the forging of a strong connection with polarimetric scattering models developed through terrestrial field measurements and airborne radar studies. During the period, advances in computing power and imaging techniques also allowed Earth-based radar experiments to acquire data at the highest spatial resolutions permitted by their transmitter systems. This paper traces these developments through a case study of lunar observations over the past 15 years, and their implications for ongoing and future Solar System radar studies.

  6. Monolithic microwave integrated circuits for sensors, radar, and communications systems; Proceedings of the Meeting, Orlando, FL, Apr. 2-4, 1991

    NASA Technical Reports Server (NTRS)

    Leonard, Regis F. (Editor); Bhasin, Kul B. (Editor)

    1991-01-01

    Consideration is given to MMICs for airborne phased arrays, monolithic GaAs integrated circuit millimeter wave imaging sensors, accurate design of multiport low-noise MMICs up to 20 GHz, an ultralinear low-noise amplifier technology for space communications, variable-gain MMIC module for space applications, a high-efficiency dual-band power amplifier for radar applications, a high-density circuit approach for low-cost MMIC circuits, coplanar SIMMWIC circuits, recent advances in monolithic phased arrays, and system-level integrated circuit development for phased-array antenna applications. Consideration is also given to performance enhancement in future communications satellites with MMIC technology insertion, application of Ka-band MMIC technology for an Orbiter/ACTS communications experiment, a space-based millimeter wave debris tracking radar, low-noise high-yield octave-band feedback amplifiers to 20 GHz, quasi-optical MESFET VCOs, and a high-dynamic-range mixer using novel balun structure.

  7. 14 CFR Appendix G to Part 121 - Doppler Radar and Inertial Navigation System (INS): Request for Evaluation; Equipment and...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Doppler Radar and Inertial Navigation... OPERATIONS Pt. 121, App. G Appendix G to Part 121—Doppler Radar and Inertial Navigation System (INS): Request... Radar or Inertial Navigation System must submit a request for evaluation of the system to the...

  8. 14 CFR Appendix G to Part 121 - Doppler Radar and Inertial Navigation System (INS): Request for Evaluation; Equipment and...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Doppler Radar and Inertial Navigation... OPERATIONS Pt. 121, App. G Appendix G to Part 121—Doppler Radar and Inertial Navigation System (INS): Request... Radar or Inertial Navigation System must submit a request for evaluation of the system to the...

  9. 14 CFR Appendix G to Part 121 - Doppler Radar and Inertial Navigation System (INS): Request for Evaluation; Equipment and...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Doppler Radar and Inertial Navigation... OPERATIONS Pt. 121, App. G Appendix G to Part 121—Doppler Radar and Inertial Navigation System (INS): Request... Radar or Inertial Navigation System must submit a request for evaluation of the system to the...

  10. Wearable system-on-a-chip UWB radar for contact-less cardiopulmonary monitoring: present status.

    PubMed

    Zito, D; Pepe, D; Mincica, M; Zito, F; De Rossi, D; Lanata, A; Scilingo, E P; Tognetti, A

    2008-01-01

    The present status of the project aimed at the realization of an innovative wearable system-on-chip UWB radar for the cardiopulmonary monitoring is presented. The overall system consists of a wearable wireless interface including a fully integrated UWB radar for the detection of the heart beat and breath rates, and a IEEE 802.15.4 ZigBee low-power radio interface. The principle of operation of the UWB radar for the monitoring of the heart wall is summarized. With respect to the prior art, this paper reports the results of the experimental characterization of the intra-body channel loss, which has been carried out successfully in order to validate the theoretical model employed for the radar system analysis. Moreover, the main building blocks of the radar have been manufactured in 90 nm CMOS technology by ST-Microelectronics and the relevant performance are resulted in excellent agreement with those expected by post-layout simulations. PMID:19163907

  11. Wearable system-on-a-chip UWB radar for contact-less cardiopulmonary monitoring: present status.

    PubMed

    Zito, D; Pepe, D; Mincica, M; Zito, F; De Rossi, D; Lanata, A; Scilingo, E P; Tognetti, A

    2008-01-01

    The present status of the project aimed at the realization of an innovative wearable system-on-chip UWB radar for the cardiopulmonary monitoring is presented. The overall system consists of a wearable wireless interface including a fully integrated UWB radar for the detection of the heart beat and breath rates, and a IEEE 802.15.4 ZigBee low-power radio interface. The principle of operation of the UWB radar for the monitoring of the heart wall is summarized. With respect to the prior art, this paper reports the results of the experimental characterization of the intra-body channel loss, which has been carried out successfully in order to validate the theoretical model employed for the radar system analysis. Moreover, the main building blocks of the radar have been manufactured in 90 nm CMOS technology by ST-Microelectronics and the relevant performance are resulted in excellent agreement with those expected by post-layout simulations.

  12. TRMM and GPM: Radar Observations and Simulations with the Local Analysis and Prediction System (LAPS)

    NASA Astrophysics Data System (ADS)

    Albers, S. C.; Holub, K.; Xie, Y.

    2015-12-01

    The Local Analysis and Prediction System (LAPS), developed at NOAAs Earth System Research Laboratory is used for data assimilation, nowcasting, and model initialization/post-processing.It is a portable system and typically runs with a high resolution and rapid updateBlends a wide variety of in-situ and remotely sensed data sets (e.g. METARs, mesonets, radar, satellite)‏Here we test the assimilation of PMM radar data, using reflectivity obtained from the TRMM satellite, as a preparation for GPM. A case study for July 26 2013 with a small region of convection occurring over Florida. The 3-D LAPS domain is on a 1km grid and is producing analyses and forecasts.TRMM radar data was remapped to mimic the appearance of reflectivity in a ground-based radar over Florida.Three assimilation experiments are being performed using non-radar observations plus: TRMM radar, ground-based radar, and neither source of radar. We are comparing both analyses (initial condition) and forecasts where the WRF modelis initialized with the LAPS analysis. When evaluating the results we consider some big picture aspects in thatthe GPM Core Observatory radar coverage is limited in space and time and potentially less operational model benefit.To address this 4DVAR can help increase impact (particularly in a global model), since it spreads observations in time and space.The spreading in time also helps compensate for latency of the real-time data stream.We can also use GPM (core satellite) radar paired with microwave imager data to calibrate microwave data from other GPM constellation satellites. We thus can leverage more frequent satellite microwave passes compared with radar to assess hydrometeor climatological covariance between various species, fill in ice phase information.These relationships, leveraged from related climate research, help to provide constraints for our planned variational analysis improvements.

  13. Airborne hyperspectral systems for solving remote sensing problems

    NASA Astrophysics Data System (ADS)

    Rodionov, I. D.; Rodionov, A. I.; Vedeshin, L. A.; Vinogradov, A. N.; Egorov, V. V.; Kalinin, A. P.

    2014-12-01

    A retrospective of airborne hyperspectrometer projects carried out in the ZAO Reagent Scientific Technical Center is presented. Hyperspectral devices developed during the period since the end of 1990s to the present day are described. The line of hyperspectrometers designed in recent times covers the ranges from ultraviolet (0.2 μm) to near infrared (1.0 μm). These devices can be mounted on airborne and automobile carriers, including small-size ones. By now, the developments of hyperspectral devices in ZAO Reagent have reached the finished state and have been prepared for serial production. Their technical characteristics permit one to speak of the creation of wide-range high-aperture ultraspectral high spatial resolution equipment with a possibility of real-time data processing on board.

  14. Progress in coherent laser radar

    NASA Technical Reports Server (NTRS)

    Vaughan, J. M.

    1986-01-01

    Considerable progress with coherent laser radar has been made over the last few years, most notably perhaps in the available range of high performance devices and components and the confidence with which systems may now be taken into the field for prolonged periods of operation. Some of this increasing maturity was evident at the 3rd Topical Meeting on Coherent Laser Radar: Technology and Applications. Topics included in discussions were: mesoscale wind fields, nocturnal valley drainage and clear air down bursts; airborne Doppler lidar studies and comparison of ground and airborne wind measurement; wind measurement over the sea for comparison with satellite borne microwave sensors; transport of wake vortices at airfield; coherent DIAL methods; a newly assembled Nd-YAG coherent lidar system; backscatter profiles in the atmosphere and wavelength dependence over the 9 to 11 micrometer region; beam propagation; rock and soil classification with an airborne 4-laser system; technology of a global wind profiling system; target calibration; ranging and imaging with coherent pulsed and CW system; signal fluctuations and speckle. Some of these activities are briefly reviewed.

  15. Snow measurement system for airborne snow surveys (GPR system from helicopter) in high mountian areas.

    NASA Astrophysics Data System (ADS)

    Sorteberg, Hilleborg K.

    2010-05-01

    In the hydropower industry, it is important to have precise information about snow deposits at all times, to allow for effective planning and optimal use of the water. In Norway, it is common to measure snow density using a manual method, i.e. the depth and weight of the snow is measured. In recent years, radar measurements have been taken from snowmobiles; however, few energy supply companies use this method operatively - it has mostly been used in connection with research projects. Agder Energi is the first Norwegian power producer in using radar tecnology from helicopter in monitoring mountain snow levels. Measurement accuracy is crucial when obtaining input data for snow reservoir estimates. Radar screening by helicopter makes remote areas more easily accessible and provides larger quantities of data than traditional ground level measurement methods. In order to draw up a snow survey system, it is assumed as a basis that the snow distribution is influenced by vegetation, climate and topography. In order to take these factors into consideration, a snow survey system for fields in high mountain areas has been designed in which the data collection is carried out by following the lines of a grid system. The lines of this grid system is placed in order to effectively capture the distribution of elevation, x-coordinates, y-coordinates, aspect, slope and curvature in the field. Variation in climatic conditions are also captured better when using a grid, and dominant weather patterns will largely be captured in this measurement system.

  16. Ground data system architecture for precipitation determination from space-based radar

    NASA Technical Reports Server (NTRS)

    Hilland, Jeffrey E.

    1989-01-01

    The Tropical Rain Mapping Radar (Tramar) is proposed as an attached payload as part of the Space Station Earth Observing System Program. Tramar would measure rainfall rates, rain velocity, and rain cell areal extent in the latitude band from 30 deg S to 30 deg N for use in studies of large-scale atmospheric circulation, variations of latent heating, tropical hydrologic processes, and mesoscale precipitation systems. The Tramar science requirements, radar design, and ground data system architecture are examined, including the three-dimensional scan geometry, the radar system performance parameters, the production of earth-gridded maps, and the telemetry, sensor, radiometric, and geophysical data that would be obtained by Tramar.

  17. Planetary Radar

    NASA Technical Reports Server (NTRS)

    Neish, Catherine D.; Carter, Lynn M.

    2015-01-01

    This chapter describes the principles of planetary radar, and the primary scientific discoveries that have been made using this technique. The chapter starts by describing the different types of radar systems and how they are used to acquire images and accurate topography of planetary surfaces and probe their subsurface structure. It then explains how these products can be used to understand the properties of the target being investigated. Several examples of discoveries made with planetary radar are then summarized, covering solar system objects from Mercury to Saturn. Finally, opportunities for future discoveries in planetary radar are outlined and discussed.

  18. Airborne Collision Detection and Avoidance for Small UAS Sense and Avoid Systems

    NASA Astrophysics Data System (ADS)

    Sahawneh, Laith Rasmi

    The increasing demand to integrate unmanned aircraft systems (UAS) into the national airspace is motivated by the rapid growth of the UAS industry, especially small UAS weighing less than 55 pounds. Their use however has been limited by the Federal Aviation Administration regulations due to collision risk they pose, safety and regulatory concerns. Therefore, before civil aviation authorities can approve routine UAS flight operations, UAS must be equipped with sense-and-avoid technology comparable to the see-and-avoid requirements for manned aircraft. The sense-and-avoid problem includes several important aspects including regulatory and system-level requirements, design specifications and performance standards, intruder detecting and tracking, collision risk assessment, and finally path planning and collision avoidance. In this dissertation, our primary focus is on developing an collision detection, risk assessment and avoidance framework that is computationally affordable and suitable to run on-board small UAS. To begin with, we address the minimum sensing range for the sense-and-avoid (SAA) system. We present an approximate close form analytical solution to compute the minimum sensing range to safely avoid an imminent collision. The approach is then demonstrated using a radar sensor prototype that achieves the required minimum sensing range. In the area of collision risk assessment and collision prediction, we present two approaches to estimate the collision risk of an encounter scenario. The first is a deterministic approach similar to those been developed for Traffic Alert and Collision Avoidance (TCAS) in manned aviation. We extend the approach to account for uncertainties of state estimates by deriving an analytic expression to propagate the error variance using Taylor series approximation. To address unanticipated intruders maneuvers, we propose an innovative probabilistic approach to quantify likely intruder trajectories and estimate the probability of

  19. Airborne Collision Detection and Avoidance for Small UAS Sense and Avoid Systems

    NASA Astrophysics Data System (ADS)

    Sahawneh, Laith Rasmi

    The increasing demand to integrate unmanned aircraft systems (UAS) into the national airspace is motivated by the rapid growth of the UAS industry, especially small UAS weighing less than 55 pounds. Their use however has been limited by the Federal Aviation Administration regulations due to collision risk they pose, safety and regulatory concerns. Therefore, before civil aviation authorities can approve routine UAS flight operations, UAS must be equipped with sense-and-avoid technology comparable to the see-and-avoid requirements for manned aircraft. The sense-and-avoid problem includes several important aspects including regulatory and system-level requirements, design specifications and performance standards, intruder detecting and tracking, collision risk assessment, and finally path planning and collision avoidance. In this dissertation, our primary focus is on developing an collision detection, risk assessment and avoidance framework that is computationally affordable and suitable to run on-board small UAS. To begin with, we address the minimum sensing range for the sense-and-avoid (SAA) system. We present an approximate close form analytical solution to compute the minimum sensing range to safely avoid an imminent collision. The approach is then demonstrated using a radar sensor prototype that achieves the required minimum sensing range. In the area of collision risk assessment and collision prediction, we present two approaches to estimate the collision risk of an encounter scenario. The first is a deterministic approach similar to those been developed for Traffic Alert and Collision Avoidance (TCAS) in manned aviation. We extend the approach to account for uncertainties of state estimates by deriving an analytic expression to propagate the error variance using Taylor series approximation. To address unanticipated intruders maneuvers, we propose an innovative probabilistic approach to quantify likely intruder trajectories and estimate the probability of

  20. 76 FR 50808 - Airborne Supplemental Navigation Equipment Using the Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-16

    ... standard for GPS sensors not augmented by satellite-based or ground- based systems (i.e., TSO-C129a Class B and Class C). The FAA has also published two GPS TSOs augmented by the satellite-based augmentation system (TSO-C145c, Airborne Navigation Sensors Using the Global Positioning System Augmented by...

  1. System aspects of the Indian MST radar facility

    NASA Technical Reports Server (NTRS)

    Viswanathan, G.

    1986-01-01

    One of the major objectives of the Indian Middle Atmosphere Program is to investigate the motions of the middle atmosphere on temporal and spatial scales and the interaction between the three height regions of the middle atmosphere. Realizing the fact that radar technique has proven to be a very powerful tool for the study of Earth atmosphere, the Indian Middle Atmosphere Program has recommended establishing a mesosphere-stratosphere-troposphere (MST) radar as a national facility for atmospheric research. The major landmarks in this attempt to setup the MST radar as a national facility are described.

  2. Comparison of lightning observations from the KSC LDAR system with radar observations from the NCAR CP-2 radar

    NASA Technical Reports Server (NTRS)

    Krehbiel, Paul; Rison, William

    1996-01-01

    This grant supported observations of thunderstorms at Kennedy Space Center during the summer of 1995. In particular, we obtained detailed observations of lightning-producing storms over KSC with the CP2 radar of the National Center for Atmospheric Research (NCAR), for the purpose of comparing these with observations from KSC's Lightning Detection and Ranging (LDAR) system. The NCAR radar was a special purpose dual-polarization system for studying the development of precipitation in storms and was at KSC for another project, the Small Cumulus Microphysics Study - SCMS. We used the radar on a non-interference basis to obtain the desired observations. In addition we recorded the electrostatic field change of the lightning discharges at two locations. Subsequent to the field observational period we compared the LDAR lightning observations with the storm structure as indicated by the radar. The results obtained to date are summarized briefly as follows: (1) The initial lightning sequence in a small developing storm was observed to occur in a region of the storm where supercooled raindrops had frozen within the previous few minutes. This is consistent with the idea that the storm electrification is produced by interactions between ice particles. (2) The lightning discharges tended to avoid regions of supercooled liquid raindrops, possibly indicating that corona from the drops reduces any electrification in the vicinity of the drops. (3) 'Bilevel' lightning discharges within storms have been confirmed to be between the level of negative charge at mid-levels in the storm and the upper storm level. This is consistent with and expands upon our understanding that storms have a basic dipolar charge structure. (4) The upward channels of the intracloud lightning discharges are often aligned with shafts of strong precipitation, and often begin just above the upper extent of 40 dBZ reflectivity in the precipitation shaft. This is consistent with a precipitation-based mechanism of

  3. A system for the real-time display of radar and video images of targets

    NASA Technical Reports Server (NTRS)

    Allen, W. W.; Burnside, W. D.

    1990-01-01

    Described here is a software and hardware system for the real-time display of radar and video images for use in a measurement range. The main purpose is to give the reader a clear idea of the software and hardware design and its functions. This system is designed around a Tektronix XD88-30 graphics workstation, used to display radar images superimposed on video images of the actual target. The system's purpose is to provide a platform for tha analysis and documentation of radar images and their associated targets in a menu-driven, user oriented environment.

  4. Final Report DE-EE0005380: Assessment of Offshore Wind Farm Effects on Sea Surface, Subsurface and Airborne Electronic Systems

    SciTech Connect

    Ling, Hao; Hamilton, Mark F.; Bhalla, Rajan; Brown, Walter E.; Hay, Todd A.; Whitelonis, Nicholas J.; Yang, Shang-Te; Naqvi, Aale R.

    2013-09-30

    Offshore wind energy is a valuable resource that can provide a significant boost to the US renewable energy portfolio. A current constraint to the development of offshore wind farms is the potential for interference to be caused by large wind farms on existing electronic and acoustical equipment such as radar and sonar systems for surveillance, navigation and communications. The US Department of Energy funded this study as an objective assessment of possible interference to various types of equipment operating in the marine environment where offshore wind farms could be installed. The objective of this project was to conduct a baseline evaluation of electromagnetic and acoustical challenges to sea surface, subsurface and airborne electronic systems presented by offshore wind farms. To accomplish this goal, the following tasks were carried out: (1) survey electronic systems that can potentially be impacted by large offshore wind farms, and identify impact assessment studies and research and development activities both within and outside the US, (2) engage key stakeholders to identify their possible concerns and operating requirements, (3) conduct first-principle modeling on the interactions of electromagnetic signals with, and the radiation of underwater acoustic signals from, offshore wind farms to evaluate the effect of such interactions on electronic systems, and (4) provide impact assessments, recommend mitigation methods, prioritize future research directions, and disseminate project findings. This report provides a detailed description of the methodologies used to carry out the study, key findings of the study, and a list of recommendations derived based the findings.

  5. A preliminary test of the application of the Lightning Detection and Ranging System (LDAR) as a thunderstorm warning and location device for the FHA including a correlation with updrafts, turbulence, and radar precipitation echoes

    NASA Technical Reports Server (NTRS)

    Poehler, H. A.

    1978-01-01

    Results of a test of the use of a Lightning Detection and Ranging (LDAR) remote display in the Patrick AFB RAPCON facility are presented. Agreement between LDAR and radar precipitation echoes of the RAPCON radar was observed, as well as agreement between LDAR and pilot's visual observations of lightning flashes. A more precise comparison between LDAR and KSC based radars is achieved by the superposition of LDAR precipitation echoes. Airborne measurements of updrafts and turbulence by an armored T-28 aircraft flying through the thunderclouds are correlated with LDAR along the flight path. Calibration and measurements of the accuracy of the LDAR System are discussed, and the extended range of the system is illustrated.

  6. Radar Symposium, 7th, Universitaet Ulm, Federal Republic of Germany, Oct. 10-12, 1989, Reports

    NASA Astrophysics Data System (ADS)

    Baur, K.

    Various papers on radar are presented. Individual topics addressed include: aspects of long-wave radiation, future NATO identification systems, experimental X-band SAR, results of first tests of the ROSAR method, concept and results of the azimuth Quick-Look Processor for the SAR aircraft, specification of an inertial navigation system for experimental SAR, detection of slowly moving targets with airborne radar, fast method for disturbance-free two-dimensional ISAR imaging, development and optimization of a coastal radar system, determination of orientation accuracy in curving trajectories, radome structures for high-frequency applications. Also discussed are: monolithically integrated GaAs switching circuits for the millimeter wave range, new pulse compression methods for periodically phase-coded signal transmission, architectures of programmable radar signal processors, evaluation of the period length of periodic signals, interactive simulation system for multisensor systems, intelligent radar data processing, knowledge-based components of a tracking system, radar signatures of highly resolving millimeter wave sensors.

  7. GLORI (GLObal navigation satellite system Reflectometry Instrument): A New Airborne GNSS-R receiver for land surface applications

    NASA Astrophysics Data System (ADS)

    Motte, Erwan; Zribi, Mehrez; Fanise, Pascal

    2015-04-01

    GLORI (GLObal navigation satellite system Reflectometry Instrument) is a new receiver dedicated to the airborne measurement of surface parameters such as soil moisture and biomass above ground and sea state (wave height and direction) above oceans. The instrument is based on the PARIS concept [Martin-Neira, 1993] using both the direct and surface-reflected L-band signals from the GPS constellation as a multistatic radar source. The receiver is based on one up-looking and one down-looking dual polarization hemispherical active antennas feeding a low-cost 4-channel SDR direct down-conversion receiver tuned to the GPS L1 frequency. The raw measurements are sampled at 16.368MHz and stored as 2-bit, IQ binary files. In post-processing, GPS acquisition and tracking are performed on the direct up-looking signal while the down-looking signal is processed blindly using tracking parameters from the direct signal. The obtained direct and reflected code-correlation waveforms are the basic observables for geophysical parameters inversion. The instrument was designed to be installed aboard the ATR42 experimental aircraft from the French SAFIRE fleet as a permanent payload. The long term goal of the project is to provide real-time continuous surface information for every flight performed. The aircraft records attitude information through its Inertial Measurement Unit and a commercial GPS receiver records additional information such as estimated doppler and code phase, receiver location, satellites azimuth and elevation. A series of test flights were performed over both the Toulouse and Gulf of Lion (Mediterranean Sea) regions during the period 17-21 Nov 2014 together with the KuROS radar [Hauser et al., 2014]. Using processing methods from the literature [Egido et al., 2014], preliminary results demonstrate the instrument sensitivity to both ground and ocean surface parameters estimation. A dedicated scientific flight campaign is planned at the end of second quarter 2015 with

  8. Airborne lidar measurements of wave energy dissipation in a coral reef lagoon system

    NASA Astrophysics Data System (ADS)

    Huang, Zhi-Cheng; Reineman, Benjamin D.; Lenain, Luc; Melville, W. Kendall; Middleton, Jason H.

    2012-03-01

    Quantification of the turbulent kinetic energy dissipation rate in the water column, ɛ, is very important for assessing nutrient uptake rates of corals and therefore the health of coral reef lagoon systems. However, the availability of such data is limited. Recently, at Lady Elliot Island (LEI), Australia, we showed that there was a strong correlation between in situ measurements of surface-wave energy dissipation and ɛ. Previously, Reineman et al. (2009), we showed that a small airborne scanning lidar system could measure the surface wavefield remotely. Here we present measurements demonstrating the use of the same airborne lidar to remotely measure surface wave energy fluxes and dissipation and thereby estimate ɛ in the LEI reef-lagoon system. The wave energy flux and wave dissipation rate across the fore reef and into the lagoon are determined from the airborne measurements of the wavefield. Using these techniques, observed spatial profiles of energy flux and wave energy dissipation rates over the LEI reef-lagoon system are presented. The results show that the high lidar backscatter intensity and point density coming from the high reflectivity of the foam from depth-limited breaking waves coincides with the high wave-energy dissipation rates. Good correlations between the airborne measurements and in situ observations demonstrate that it is feasible to apply airborne lidar systems for large-scale, long-term studies in monitoring important physical processes in coral reef environments. When added to other airborne techniques, the opportunities for efficient monitoring of large reef systems may be expanded significantly.

  9. Operation of a Radar Altimeter over the Greenland Ice Sheet

    NASA Technical Reports Server (NTRS)

    Grund, Matthew D.

    1996-01-01

    This thesis presents documentation for the Advanced Application Flight Experiment (AAFE) pulse compression radar altimeter and its role in the NASA Multisensor Airborne Altimetry Experiment over Greenland in 1993. The AAFE Altimeter is a Ku-band microwave radar which has demonstrated 14 centimeter range precision in operation over arctic ice. Recent repairs and improvements were required to make the Greenland missions possible. Transmitter, receiver and software modifications, as well as the integration of a GPS receiver are thoroughly documented. Procedures for installation, and operation of the radar are described. Finally, suggestions are made for further system improvements.

  10. Earth resources shuttle imaging radar. [systems analysis and design analysis of pulse radar for earth resources information system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A report is presented on a preliminary design of a Synthetic Array Radar (SAR) intended for experimental use with the space shuttle program. The radar is called Earth Resources Shuttle Imaging Radar (ERSIR). Its primary purpose is to determine the usefulness of SAR in monitoring and managing earth resources. The design of the ERSIR, along with tradeoffs made during its evolution is discussed. The ERSIR consists of a flight sensor for collecting the raw radar data and a ground sensor used both for reducing these radar data to images and for extracting earth resources information from the data. The flight sensor consists of two high powered coherent, pulse radars, one that operates at L and the other at X-band. Radar data, recorded on tape can be either transmitted via a digital data link to a ground terminal or the tape can be delivered to the ground station after the shuttle lands. A description of data processing equipment and display devices is given.

  11. Michigan experimental multispectral mapping system: A description of the M7 airborne sensor and its performance

    NASA Technical Reports Server (NTRS)

    Hasell, P. G., Jr.

    1974-01-01

    The development and characteristics of a multispectral band scanner for an airborne mapping system are discussed. The sensor operates in the ultraviolet, visual, and infrared frequencies. Any twelve of the bands may be selected for simultaneous, optically registered recording on a 14-track analog tape recorder. Multispectral imagery recorded on magnetic tape in the aircraft can be laboratory reproduced on film strips for visual analysis or optionally machine processed in analog and/or digital computers before display. The airborne system performance is analyzed.

  12. A combined quality-control methodology in Ebro Delta (NE Spain) high frequency radar system

    NASA Astrophysics Data System (ADS)

    Lorente, P.; Piedracoba, S.; Soto-Navarro, J.; Alvarez-Fanjul, E.

    2015-08-01

    Ebro River Delta is a relevant marine protected area in the western Mediterranean. In order to promote the conservation of its ecosystem and support operational decision making in this sensitive area, a three site standard-range (13.5 MHz) CODAR SeaSonde High Frequency (HF) radar was deployed in 2013. Since there is a growing demand for reliable HF radar surface current measurements, the main goal of this work is to present a combined quality control methodology. Firstly, one year-long (2014) real-time web monitoring of nonvelocity-based diagnostic parameters is conducted in order to infer both radar site status and HF radar system performance. Signal-to-noise ratio at the monopole exhibited a consistent monthly evolution although some abrupt decreases (below 10 dB), occasionally detected in June for one of the radar sites, impacted negatively on the spatiotemporal coverage of total current vectors. It seemed to be a sporadic episode since radar site overall performance was found to be robust during 2014. Secondly, a validation of HF radar data with independent in situ observations from a moored current meter was attempted for May-October 2014. The accuracy assessment of radial and total vectors revealed a consistently high agreement. The directional accuracy of the HF radar was rated at better than 8°. The correlation coefficient and RMSE values emerged in the ranges 0.58-0.83 and 4.02-18.31 cm s-1, respectively. The analysis of the monthly averaged current maps for 2014 showed that the HF radar properly represented basic oceanographic features previously reported, namely: the predominant southwestward flow, the coastal clockwise eddy confined south of Ebro Delta mouth or the Ebro River impulsive-type freshwater discharge. Future works should include the use of verified HF radar data for the rigorous skill assessment of operational ocean circulation systems currently running in Ebro estuarine region like MyOcean IBI.

  13. Radar based Ground Level Reconstruction Utilizing a Hypocycloid Antenna Positioning System

    NASA Astrophysics Data System (ADS)

    Baer, Christoph; Musch, Thomas

    2015-01-01

    In this contribution we introduce a novel radar positioning system. It makes use of a mathematical curve, called hypocycloid, for a slanting movement of the radar antenna. By means of a planetary gear, a ball, and a universal joint as well as a stepping motor, a two dimensional positioning is provided by a uniaxial drive shaft exclusively. The fundamental position calculation and different signal processing algorithms are presented. By means of an 80 GHz FMCW radar system we performed several measurements on objects with discrete heights as well as on objects with continuous surfaces. The results of these investigations are essential part of this contribution and are discussed in detail.

  14. Estimation of Microphysical and Radiative Parameters of Precipitating Cloud Systems Using mm-Wavelength Radars

    NASA Astrophysics Data System (ADS)

    Matrosov, Sergey Y.

    2009-03-01

    A remote sensing approach is described to retrieve cloud and rainfall parameters within the same precipitating system. This approach is based on mm-wavelength radar signal attenuation effects which are observed in a layer of liquid precipitation containing clouds and rainfall. The parameters of ice clouds in the upper part of startiform precipitating systems are then retrieved using the absolute measurements of radar reflectivity. In case of the ground-based radar location, these measurements are corrected for attenuation in the intervening layer of liquid hydrometers.

  15. Measurement of lake ice thickness with a short-pulse radar system

    NASA Technical Reports Server (NTRS)

    Cooper, D. W.; Mueller, R. A.; Schertler, R. J.

    1976-01-01

    Measurements of lake ice thickness were made during March 1975 at the Straits of Mackinac by using a short-pulse radar system aboard an all-terrain vehicle. These measurements were compared with ice thicknesses determined with an auger. Over 25 sites were explored which had ice thicknesses in the range 29 to 60 cm. The maximum difference between radar and auger measurements was less than 9.8 percent. The magnitude of the error was less than + or - 3.5 cm. The NASA operating short-pulse radar system used in monitoring lake ice thickness from an aircraft is also described.

  16. Optical-network-connected multi-channel 96-GHz-band distributed radar system

    NASA Astrophysics Data System (ADS)

    Kanno, Atsushi; Kuri, Toshiaki; Kawanishi, Tetsuya

    2015-05-01

    The millimeter-wave (MMW) radar is a promising candidate for high-precision imaging because of its short wavelength and broad range of available bandwidths. In particular in the frequency range of 92-100 GHz, which is regulated for radiolocation, an atmospheric attenuation coefficient less than 1 dB/km limits the imaging range. Therefore, a combination of MMW radar and distributed antenna system directly connected to optical fiber networks can realize both high-precision imaging and large-area surveillance. In this paper, we demonstrate a multi-channel MMW frequency-modulated continuous-wave distributed radar system connected to an analog radio-over-fiber network.

  17. A Reduced Power Digital Electronics System for a Digital Beamforming Space Exploration Synthetic Aperture Radar

    NASA Astrophysics Data System (ADS)

    Carter, L. M.; Rincon, R. F.; Novak, M.

    2016-10-01

    We will discuss design of an orbital P-band (70 cm wavelength) digital beamforming radar system that is modular and can be used for imaging polarimetry of Earth and rocky planets and moons, as well as asteroids and comets.

  18. Effect of an electrostatic space charge system on airborne dust and subsequent potential transmission of microorganisms to broiler breeder pullets by airborne dust.

    PubMed

    Richardson, L J; Mitchell, B W; Wilson, J L; Hofacre, C L

    2003-01-01

    High levels of dust and microorganisms are known to be associated with animal confinement rearing facilities. Many of the microorganisms are carried by dust particles, thus providing an excellent vector for horizontal disease transmission between birds. Two environmentally controlled rooms containing female broiler breeder pullets (n = 300) were used to evaluate the effectiveness of an electrostatic space charge system (ESCS) in reducing airborne dust and gram-negative bacteria levels over an 8-wk period (starting when the birds were 10 wk old). The ESCS was used to evaluate the effectiveness of reducing airborne microorganism levels by charging airborne dust particles and causing the particles to be attracted to grounded surfaces (i.e., walls, floor, equipment). The use of the ESCS resulted in a 64% mean reduction in gram-negative bacteria. Airborne dust levels were reduced an average of 37% over a 1-wk period in the experimental room compared with the control room on the basis of samples taken every 10 min. The reductions of airborne dust and bacteria in this study are comparable with earlier results obtained with the ESCS in commercial hatching cabinets and experimental caged layer rooms, suggesting the system could also be applied to other types of enclosed animal housing. PMID:12713167

  19. Autonomous system for initializing synthetic aperture radar seeker acquisition

    SciTech Connect

    Hamilton, P.C.

    1993-08-03

    A method is described of guiding a missile having an active seeker including a synthetic aperture radar operating in a squint mode to a target aircraft having a search radar therein the maximum range of active seeker acquisition being within said missile's maneuver capability to intercept, and the maximum range of active seeker acquisition not exceeding the capability of the active seeker, said method comprising the steps of: launching said missile in response to detection of the search radar; implementing a passive seeker mode of operation to passively guide said missile towards said target aircraft in a manner to avoid detection of said missile by said target aircraft; transferring from said passive seeker mode to an active seeker mode in response to detected shutdown of said search radar; maneuvering said missile to execute a turn angle away from said target aircraft such that the search field of said synthetic aperture radar sweeps through an entire target uncertainty volume, said turn angle being within a first preselected limit and a second preselected limit such that said target aircraft does not cross over said missile's terminal flight path; and intercepting said target aircraft within a lethal range of said missile.

  20. Simulating and testing autonomous behaviour in multiple airborne sensor systems

    NASA Astrophysics Data System (ADS)

    Smith, Moira I.; Hernandez, Marcel L.; Cooper, Matthew

    2007-04-01

    The Multiple Airborne Sensor Targeting and Evaluation Rig (MASTER) is a high fidelity simulation environment in which data fusion, tracking and sensor management algorithms developed within QinetiQ Ltd. can be demonstrated and evaluated. In this paper we report an observer trajectory planning tool that adds considerable functionality to MASTER. This planning tool can coordinate multiple sensor platforms in tracking highly manoeuvring targets. It does this by applying instantaneous thrusts to each platform, the magnitude of which is chosen to gain maximum observability of the target. We use an efficient search technique to determine the thrust that should be applied to each platform at each time step, and the planning horizon can either be one-step (greedy) or two-step. The measure of performance used in evaluating each potential sensor manoeuvre (thrust) is the posterior Cramer-Rao lower bound (PCRLB), which gives the best possible (lowest mean square error) tracking performance. We exploit a recent novel approach to approximating the PCRLB for manoeuvring target tracking (the "best-fitting Gaussian" (BFG) approach: Hernandez et al., 2005). A closed-form expression gives the BFG approximation at each sampling time. Hence, the PCRLB can be approximated with a very low computational overhead. As a result, the planning tool can be implemented as an aid to decision-making in real-time, even in this time-critical airborne domain. The functionality of MASTER enables one to access the performance of the planning tool in a range of sensor-target scenarios, enabling one to determine the minimal sensor requirement in order to satisfy mission requirements.

  1. Windshear detection radar signal processing studies

    NASA Technical Reports Server (NTRS)

    Baxa, Ernest G., Jr.

    1993-01-01

    This final report briefly summarizes research work at Clemson in the Radar Systems Laboratory under the NASA Langley Research Grant NAG-1-928 in support of the Antenna and Microwave Branch, Guidance and Control Division, program to develop airborne sensor technology for the detection of low altitude windshear. A bibliography of all publications generated by Clemson personnel is included. An appendix provides abstracts of all publications.

  2. Simulation of Terminal-Area Flight Management System Arrivals with Airborne Spacing

    NASA Technical Reports Server (NTRS)

    Callantine, Todd J.; Lee, Paul U.; Mercer, Joey S.; Palmer, Everett A.; Prevot, Thomas

    2007-01-01

    A simulation evaluated the feasibility and potential benefits of using decision support tools to support time-based airborne spacing and merging for aircraft arriving in the terminal area on charted Flight Management System (FMS) routes. Sixteen trials were conducted in each treatment combination of a 2X2 repeated-measures design. In trials 'with ground tools' air traffic controller participants managed traffic using sequencing and spacing tools. In trials 'with air tools' approximately seventy-five percent of aircraft assigned to the primary landing runway were equipped for airborne spacing, including flight simulators flown by commercial pilots. The results indicate that airborne spacing improves spacing accuracy and is feasible for FMS operations and mixed spacing equipage. Controllers and pilots can manage spacing clearances that contain two call signs without difficulty. For best effect, both decision support tools and spacing guidance should exhibit consistently predictable performance, and merging traffic flows should be well coordinated.

  3. FMCW radar for the sense function of sense and avoid systems onboard UAVs

    NASA Astrophysics Data System (ADS)

    Itcia, Eric; Wasselin, Jean-Philippe; Mazuel, Sébastien; Otten, Matern; Huizing, Albert

    2013-10-01

    Rockwell Collins France (RCF) radar department is currently developing, in close collaboration with TNO in The Hague, The Netherlands, a Frequency Modulated Continuous Wave (FMCW) radar sensor dedicated to Obstacle Warning function and potentially to air traffic detection. The sensor combines flood light illumination and digital beam forming to accommodate demanding detection and coverage requirements. Performances have been evaluated in flight tests and results prove that such a radar sensor is a good candidate for the Sense Function of Sense and Avoid Systems onboard UAV.

  4. System characteristics design of WindRadar on FengYun-3E meteorological satellite

    NASA Astrophysics Data System (ADS)

    Yin, Honggang; Fan, Ziping; Dou, Fangli

    2014-11-01

    Spaceborne microwave scatterometers have successfully provided global ocean surface wind field for two decades. However current scatterometers still cannot satisfy the requirement of achieve ocean wind vectors in nearly all weather and all wind conditions. A new microwave scatterometer - the WindRadar with dual frequency onboard Chinese FengYun-3E meteorological satellite is being developed to attempt to overcome their shortcomings. This paper introduces the objectives of the WindRadar, then describes the design of its some key system characteristics, and the performance of the WindRadar is also analyzed at the end.

  5. An investigation of using a phase-change material to improve the heat transfer in a small electronic module for an airborne radar application

    SciTech Connect

    Snyder, K.W.

    1990-10-01

    Finding new and improved means of cooling small electronic packages are of great importance to today's electronic packaging engineer. Thermal absorption through the use of a material which changes phase is an attractive alternative. Taking advantage of the heat capacity of a material's latent heat of fusion is shown to absorb heat away from the electronics, thus decreasing the overall temperature rise of the system. The energy equation is formulated in terms of enthalpy and discretized using a finite-difference method. A FORTRAN program to solve the discretized equations is presented which can be used to analyze heat conduction in a rectangular region undergoing an isothermal phase change. An analysis of heat transfer through a miniature radar electronic module cooled by a phase-change reservoir is presented, illustrating the method's advantages over conventional heat sinks. 41 refs., 11 figs., 2 tabs.

  6. Structural geologic interpretations from radar imagery

    USGS Publications Warehouse

    Reeves, Robert G.

    1969-01-01

    Certain structural geologic features may be more readily recognized on sidelooking airborne radar (SLAR) images than on conventional aerial photographs, other remote sensor imagery, or by ground observations. SLAR systems look obliquely to one or both sides and their images resemble aerial photographs taken at low sun angle with the sun directly behind the camera. They differ from air photos in geometry, resolution, and information content. Radar operates at much lower frequencies than the human eye, camera, or infrared sensors, and thus "sees" differently. The lower frequency enables it to penetrate most clouds and some precipitation, haze, dust, and some vegetation. Radar provides its own illumination, which can be closely controlled in intensity and frequency. It is narrow band, or essentially monochromatic. Low relief and subdued features are accentuated when viewed from the proper direction. Runs over the same area in significantly different directions (more than 45° from each other), show that images taken in one direction may emphasize features that are not emphasized on those taken in the other direction; optimum direction is determined by those features which need to be emphasized for study purposes. Lineaments interpreted as faults stand out on radar imagery of central and western Nevada; folded sedimentary rocks cut by faults can be clearly seen on radar imagery of northern Alabama. In these areas, certain structural and stratigraphic features are more pronounced on radar images than on conventional photographs; thus radar imagery materially aids structural interpretation.

  7. Airborne Wireless Optical Communication System in Low Altitude Using an Unmanned Aerial Vehicle and LEDs

    NASA Astrophysics Data System (ADS)

    Kong, Meiwei; Tong, Zheng; Yu, Xiangyu; Song, Yuhang; Lin, Aobo; Xu, Jing

    2016-02-01

    In this paper, we demonstrate the feasibility of airborne wireless optical communication system using an unmanned aerial vehicle and LEDs. Monte Carlo simulation method is used to evaluate the performance of the communication channel. Considering OOK modulation, we illustrate how the BER performance is affected by the link distance, the divergence angel and the deflection angel of the light source.

  8. An airborne multispectral imaging system based on two consumer-grade cameras for agricultural remote sensing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper describes the design and evaluation of an airborne multispectral imaging system based on two identical consumer-grade cameras for agricultural remote sensing. The cameras are equipped with a full-frame complementary metal oxide semiconductor (CMOS) sensor with 5616 × 3744 pixels. One came...

  9. Spaceborne radar

    NASA Technical Reports Server (NTRS)

    Moore, R. K.; Eckerman, J.; Meneghini, R.; Atlas, D.; Boerner, W. M.; Cherry, S.; Clark, J. F.; Doviak, R. J.; Goldhirsh, J.; Lhermitte, R. M.

    1981-01-01

    The spaceborne radar panel considered how radar could be used to measure precipitation from satellites. The emphasis was on how radar could be used with radiometry (at microwave, visible (VIS), and infrared (IR) wavelengths) to reduce the uncertainties of measuring precipitation with radiometry alone. In addition, the fundamental electromagnetic interactions involved in the measurements were discussed to determine the key work areas for research and development to produce effective instruments. Various approaches to implementing radar systems on satellites were considered for both shared and dedicated instruments. Finally, a research and development strategy was proposed for establishing the parametric relations and retrieval algorithms required for extracting precipitation information from the radar and associated radiometric data.

  10. Standoff concealed weapon detection using a 350 GHz radar imaging system

    SciTech Connect

    Sheen, David M.; Hall, Thomas E.; Severtsen, Ronald H.; McMakin, Douglas L.; Hatchell, Brian K.; Valdez, Patrick LJ

    2010-04-01

    The Pacific Northwest National Laboratory is currently developing a 350 GHz, active, wideband, three-dimensional, radar imaging system to evaluate the feasibility of active sub-mm imaging for standoff concealed weapon detection. The prototype radar imaging system is based on a wideband, heterodyne, frequency-multiplier-based transceiver system coupled to a quasi-optical focusing system and high-speed rotating conical scanner. The wideband operation of this system provides accurate ranging information, and the images obtained are fully three-dimensional. Recent improvements to the system include increased imaging speed using improved balancing techniques, wider bandwidth, and image display techniques.

  11. The development of airborne video system for monitoring of river environments

    SciTech Connect

    Yoshikawa, Shigeya; Mizutani, Nobuyuki; Mizukami, Masumi; Koyano, Toshirou

    1996-11-01

    Recently, airborne videography is widely used by many monitoring for environmental resources, such as rivers, forests, ocean, and so on. Although airborne videography has a low resolution than aerial photographs, it can effectively reduce the cost of continuous monitoring of wide area. Furthermore video images can easily be processed with personal computer. This paper introduces an airborne video system for monitoring of Class A river environment. This system consists of two sub-systems. One is the data collection system that is composed of a video camera, a Global Positioning System(GPS) and a personal computer. This sub-system records information of rivers by video images and their corresponding location data. A GPS system is used for calculating location data and navigating the airplane to the destination of monitoring site. Other is a simplified digital video editing system. This system runs on a personal computer with Microsoft Windows 3.1. This system can also be used for management and planning of road environment, marine resources, forest resources and for prevention of disasters. 7 refs., 4 figs.

  12. Thermal management of closed computer modules utilizing high density circuitry. [in Airborne Information Management System

    NASA Technical Reports Server (NTRS)

    Hoadley, A. W.; Porter, A. J.

    1990-01-01

    This paper presents data on a preliminary analysis of the thermal dynamic characteristics of the Airborne Information Management System (AIMS), which is a continuing design project at NASA Dryden. The analysis established the methods which will be applied to the actual AIMS boards as they become available. The paper also describes the AIMS liquid cooling system design and presents a thermodynamic computer model of the AIMS cooling system, together with an experimental validation of this model.

  13. Radar monitoring of oil pollution

    NASA Technical Reports Server (NTRS)

    Guinard, N. W.

    1970-01-01

    Radar is currently used for detecting and monitoring oil slicks on the sea surface. The four-frequency radar system is used to acquire synthetic aperature imagery of the sea surface on which the oil slicks appear as a nonreflecting area on the surface surrounded by the usual sea return. The value of this technique was demonstrated, when the four-frequency radar system was used to image the oil spill of tanker which has wrecked. Imagery was acquired on both linear polarization (horizontal, vertical) for frequencies of 428, 1228, and 8910 megahertz. Vertical returns strongly indicated the presence of oil while horizontal returns failed to detect the slicks. Such a result is characteristic of the return from the sea and cannot presently be interpreted as characteristics of oil spills. Because an airborne imaging radar is capable of providing a wide-swath coverage under almost all weather conditions, it offers promise in the development of a pollution-monitoring system that can provide a coastal watch for oil slicks.

  14. High-resolution imaging using a wideband MIMO radar system with two distributed arrays.

    PubMed

    Wang, Dang-wei; Ma, Xiao-yan; Chen, A-Lei; Su, Yi

    2010-05-01

    Imaging a fast maneuvering target has been an active research area in past decades. Usually, an array antenna with multiple elements is implemented to avoid the motion compensations involved in the inverse synthetic aperture radar (ISAR) imaging. Nevertheless, there is a price dilemma due to the high level of hardware complexity compared to complex algorithm implemented in the ISAR imaging system with only one antenna. In this paper, a wideband multiple-input multiple-output (MIMO) radar system with two distributed arrays is proposed to reduce the hardware complexity of the system. Furthermore, the system model, the equivalent array production method and the imaging procedure are presented. As compared with the classical real aperture radar (RAR) imaging system, there is a very important contribution in our method that the lower hardware complexity can be involved in the imaging system since many additive virtual array elements can be obtained. Numerical simulations are provided for testing our system and imaging method.

  15. High-resolution imaging using a wideband MIMO radar system with two distributed arrays.

    PubMed

    Wang, Dang-wei; Ma, Xiao-yan; Chen, A-Lei; Su, Yi

    2010-05-01

    Imaging a fast maneuvering target has been an active research area in past decades. Usually, an array antenna with multiple elements is implemented to avoid the motion compensations involved in the inverse synthetic aperture radar (ISAR) imaging. Nevertheless, there is a price dilemma due to the high level of hardware complexity compared to complex algorithm implemented in the ISAR imaging system with only one antenna. In this paper, a wideband multiple-input multiple-output (MIMO) radar system with two distributed arrays is proposed to reduce the hardware complexity of the system. Furthermore, the system model, the equivalent array production method and the imaging procedure are presented. As compared with the classical real aperture radar (RAR) imaging system, there is a very important contribution in our method that the lower hardware complexity can be involved in the imaging system since many additive virtual array elements can be obtained. Numerical simulations are provided for testing our system and imaging method. PMID:20051345

  16. Comparison of immersed liquid and air cooling of NASA's Airborne Information Management System

    NASA Astrophysics Data System (ADS)

    Hoadley, A. W.; Porter, A. J.

    1992-07-01

    The Airborne Information Management System (AIMS) is currently under development at NASA Dryden Flight Research Facility. The AIMS is designed as a modular system utilizing surface mounted integrated circuits in a high-density configuration. To maintain the temperature of the integrated circuits within manufacturer's specifications, the modules are to be filled with Fluorinert FC-72. Unlike ground based liquid cooled computers, the extreme range of the ambient pressures experienced by the AIMS requires the FC-72 be contained in a closed system. This forces the latent heat absorbed during the boiling to be released during the condensation that must take within the closed module system. Natural convection and/or pumping carries the heat to the outer surface of the AIMS module where the heat transfers to the ambient air. This paper will present an evaluation of the relative effectiveness of immersed liquid cooling and air cooling of the Airborne Information Management System.

  17. Comparison of immersed liquid and air cooling of NASA's Airborne Information Management System

    NASA Technical Reports Server (NTRS)

    Hoadley, A. W.; Porter, A. J.

    1992-01-01

    The Airborne Information Management System (AIMS) is currently under development at NASA Dryden Flight Research Facility. The AIMS is designed as a modular system utilizing surface mounted integrated circuits in a high-density configuration. To maintain the temperature of the integrated circuits within manufacturer's specifications, the modules are to be filled with Fluorinert FC-72. Unlike ground based liquid cooled computers, the extreme range of the ambient pressures experienced by the AIMS requires the FC-72 be contained in a closed system. This forces the latent heat absorbed during the boiling to be released during the condensation that must take within the closed module system. Natural convection and/or pumping carries the heat to the outer surface of the AIMS module where the heat transfers to the ambient air. This paper will present an evaluation of the relative effectiveness of immersed liquid cooling and air cooling of the Airborne Information Management System.

  18. PHARUS airborne SAR concept

    NASA Astrophysics Data System (ADS)

    Snoeij, Paul; Pouwels, Henk; Koomen, Peter J.; Hoogeboom, Peter

    1995-11-01

    PHARUS (phased array universal SAR) is an airborne SAR concept which is being developed in the Netherlands. The PHARUS system differs from other airborne SARs by the use of a phased array antenna, which provides both for the flexibility in the design as well as for a compact, light-weight instrument that can be carried on small aircraft. The concept allows for the construction of airborne SAR systems on a common generic basis but tailored to specific user needs and can be seen as a preparation for future spaceborne SAR systems using solid state transmitters with electronically steerable phased array antenna. The whole approach is aimed at providing an economic and yet technically sophisticated solution to remote sensing or surveying needs of a specific user. The solid state phased array antenna consists of a collection of radiating patches; the design flexibility for a large part resides in the freedom to choose the number of patches, and thereby the essential radar performance parameters such as resolution and swath width. Another consequence of the use of the phased array antenna is the system's compactness and the possibility to rigidly mount it on a small aircraft. The use of small aircraft of course considerably improves the cost/benefit ratio of the use of airborne SAR. Flight altitude of the system is flexible between about 7,000 and 40,000 feet, giving much operational freedom within the meteo and airspace control limits. In the PHARUS concept the airborne segment is complemented by a ground segment, which consists of a SAR processor, possibly extended by a matching image processing package. (A quick look image is available in real-time on board the aircraft.) The SAR processor is UNIX based and runs on easily available hardware (SUN station). Although the additional image processing software is available, the SAR processing software is nevertheless designed to be able to interface with commercially available image processing software, as well as being able

  19. Ultrawideband radar echoes of land mine targets measured at oblique incidence using a 250-kW impulse radar system

    NASA Astrophysics Data System (ADS)

    Chant, Ian J.; Staines, Geoff

    1997-07-01

    United Nations Peacekeeping forces around the world need to transport food, personnel and medical supplies through disputed regions were land mines are in active use as road blocks and terror weapons. A method of fast, effective land mine detection is needed to combat this threat to road transport. The technique must operate from a vehicle travelling at a reasonable velocity and give warning far enough ahead for the vehicle to stop in time to avoid the land mine. There is particular interest in detecting low- metallic content land mines. One possible solutionis the use of ultra-wide-band (UWB) radar. The Australian Defence Department is investigating the feasibility of using UWB radar for land mine detection from a vehicle. A 3 GHz UWB system has been used to collect target response from a series of inert land mines and mine-like objects placed on the ground and buried in the ground. The targets measured were a subset of those in the target set described in Wong et al. with the addition of inert land mines corresponding to some of the surrogate targets in this set. The results are encouraging for the detection of metallic land mines and the larger non-metallic land mines. Smaller low-metallic- content anti-personnel land mines are less likely to be detected.

  20. Use of a new high-speed digital data acquisition system in airborne ice-sounding

    USGS Publications Warehouse

    Wright, David L.; Bradley, Jerry A.; Hodge, Steven M.

    1989-01-01

    A high-speed digital data acquisition and signal averaging system for borehole, surface, and airborne radio-frequency geophysical measurements was designed and built by the US Geological Survey. The system permits signal averaging at rates high enough to achieve significant signal-to-noise enhancement in profiling, even in airborne applications. The first field use of the system took place in Greenland in 1987 for recording data on a 150 by 150-km grid centered on the summit of the Greenland ice sheet. About 6000-line km were flown and recorded using the new system. The data can be used to aid in siting a proposed scientific corehole through the ice sheet.