Sample records for airborne sar system

  1. Processor architecture for airborne SAR systems

    NASA Technical Reports Server (NTRS)

    Glass, C. M.

    1983-01-01

    Digital processors for spaceborne imaging radars and application of the technology developed for airborne SAR systems are considered. Transferring algorithms and implementation techniques from airborne to spaceborne SAR processors offers obvious advantages. The following topics are discussed: (1) a quantification of the differences in processing algorithms for airborne and spaceborne SARs; and (2) an overview of three processors for airborne SAR systems.

  2. Airborne SAR systems for infrastructures monitoring

    NASA Astrophysics Data System (ADS)

    Perna, Stefano; Berardino, Paolo; Esposito, Carmen; Natale, Antonio

    2017-04-01

    The present contribution is aimed at showing the capabilities of Synthetic Aperture Radar (SAR) systems mounted onboard airborne platforms for the monitoring of infrastructures. As well known, airborne SAR systems guarantee narrower spatial coverage than satellite sensors [1]. On the other side, airborne SAR products are characterized by geometric resolution typically higher than that achievable in the satellite case, where larger antennas must be necessarily exploited. More important, airborne SAR platforms guarantee operational flexibility significantly higher than that achievable with satellite systems. Indeed, the revisit time between repeated SAR acquisitions in the satellite case cannot be freely decided, whereas in the airborne case it can be kept very short. This renders the airborne platforms of key interest for the monitoring of infrastructures, especially in case of emergencies. However, due to the platform deviations from a rectilinear, reference flight track, the generation of airborne SAR products is not a turn of the crank procedure as in the satellite case. Notwithstanding proper algorithms exist in order to circumvent this kind of limitations. In this work, we show how the exploitation of airborne SAR sensors, coupled to the use of such algorithms, allows obtaining high resolution monitoring of infrastructures in urban areas. [1] G. Franceschetti, and R.Lanari, Synthetic Aperture Radar Processing, CRC PRESS, New York, 1999.

  3. 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

  4. Calibration and Validation of Airborne InSAR Geometric Model

    NASA Astrophysics Data System (ADS)

    Chunming, Han; huadong, Guo; Xijuan, Yue; Changyong, Dou; Mingming, Song; Yanbing, Zhang

    2014-03-01

    The image registration or geo-coding is a very important step for many applications of airborne interferometric Synthetic Aperture Radar (InSAR), especially for those involving Digital Surface Model (DSM) generation, which requires an accurate knowledge of the geometry of the InSAR system. While the trajectory and attitude instabilities of the aircraft introduce severe distortions in three dimensional (3-D) geometric model. The 3-D geometrical model of an airborne SAR image depends on the SAR processor itself. Working at squinted model, i.e., with an offset angle (squint angle) of the radar beam from broadside direction, the aircraft motion instabilities may produce distortions in airborne InSAR geometric relationship, which, if not properly being compensated for during SAR imaging, may damage the image registration. The determination of locations of the SAR image depends on the irradiated topography and the exact knowledge of all signal delays: range delay and chirp delay (being adjusted by the radar operator) and internal delays which are unknown a priori. Hence, in order to obtain reliable results, these parameters must be properly calibrated. An Airborne InSAR mapping system has been developed by the Institute of Remote Sensing and Digital Earth (RADI), Chinese Academy of Sciences (CAS) to acquire three-dimensional geo-spatial data with high resolution and accuracy. To test the performance of the InSAR system, the Validation/Calibration (Val/Cal) campaign has carried out in Sichun province, south-west China, whose results will be reported in this paper.

  5. ISRO's dual frequency airborne SAR pre-cursor to NISAR

    NASA Astrophysics Data System (ADS)

    Ramanujam, V. Manavala; Suneela, T. J. V. D.; Bhan, Rakesh

    2016-05-01

    The Indian Space Research Organisation (ISRO) and the National Aeronautics and Space Administration (NASA) have jointly embarked on NASA-ISRO Synthetic Aperture Radar (NISAR) operating in L-band and S-band, which will map Earth's surface every 12 days. As a pre-cursor to the NISAR mission, ISRO is planning an airborne SAR (L&S band) which will deliver NISAR analogue data products to the science community. ISRO will develop all the hardware with the aim of adhering to system design aspects of NISAR to the maximum extent possible. It is a fully polarimetric stripmap SAR and can be operated in single, dual, compact, quasi-quad and full polarimetry modes. It has wide incidence angle coverage from 24°-77° with swath coverage from 5.5km to 15 km. Apart from simultaneous imaging operations, this system can also operate in standalone L/S SAR modes. This system is planned to operate from an aircraft platform with nominal altitude of 8000meters. Antenna for this SAR will be rigidly mounted to the aircraft, whereas, motion compensation will be implemented in the software processor to generate data products. Data products for this airborne SAR will be generated in slant & ground range azimuth dimension and geocoded in HDF5/Geotiff formats. This airborne SAR will help to prepare the Indian scientific community for optimum utilization of NISAR data. In-order to collect useful science data, airborne campaigns are planned from end of 2016 onwards.

  6. Evaluation of the Potentials and Challenges of an Airborne InSAR System for Deformation Mapping: A Case Study over the Slumgullion Landslide

    NASA Astrophysics Data System (ADS)

    Cao, N.; Lee, H.; Zaugg, E.; Shrestha, R. L.; Carter, W. E.; Glennie, C. L.; Wang, G.; Lu, Z.; Diaz, J. C. F.

    2016-12-01

    Synthetic aperture radar (SAR) interferometry (InSAR) is a technique which uses two or more SAR images of the same area to estimate landscape topography or ground surface displacement. Differential InSAR (DInSAR) is capable of measuring ground displacements at the millimeter level, but a major drawback of traditional DInSAR is that only the deformation along the line-of-sight direction can be detected. Because most of the current spaceborne SAR systems have near-polar, sun-synchronous orbits, deformation measurements in the South-North direction are limited (except for polar regions). Compared with spaceborne SAR, airborne SAR systems have the advantages of flexible scanning geometry and revisit time, high spatial resolution, and no ionospheric distortion. In this study, we present a case study of the Slumgullion landslide conducted in July 2015 to assess an airborne SAR system known as ARTEMIS SlimSAR, which is a compact, modular, and multi-frequency radar system. The Slumgullion landslide, located in the San Juan Mountains near Lake City, Colorado is a long-term slow moving landslide that moves downhill continuously. For this study, the L-band SlimSAR was installed and data were collected on July 3, 7, and 10 and processed using the time-domain backprojection algorithm. GPS surveys and spaceborne DInSAR analysis using COSMO-SkyMed images were also conducted to verify the performance of the airborne SAR system. The airborne DInSAR results showed satisfying agreement with the GPS and spaceborne DInSAR results. The root mean square of the differences between the SlimSAR, and GPS and satellite derived velocities, were 0.6 mm/day, and 0.9 mm/day, respectively. A 3-D deformation map over Slumgullion landslide was generated, which displayed distinct correlation between the landslide motion and topography. This study also indicated that the primary source of the error for the SlimSAR system is the trajectory turbulences of the aircraft. The effect of the trajectory

  7. Research on Airborne SAR Imaging Based on Esc Algorithm

    NASA Astrophysics Data System (ADS)

    Dong, X. T.; Yue, X. J.; Zhao, Y. H.; Han, C. M.

    2017-09-01

    Due to the ability of flexible, accurate, and fast obtaining abundant information, airborne SAR is significant in the field of Earth Observation and many other applications. Optimally the flight paths are straight lines, but in reality it is not the case since some portion of deviation from the ideal path is impossible to avoid. A small disturbance from the ideal line will have a major effect on the signal phase, dramatically deteriorating the quality of SAR images and data. Therefore, to get accurate echo information and radar images, it is essential to measure and compensate for nonlinear motion of antenna trajectories. By means of compensating each flying trajectory to its reference track, MOCO method corrects linear phase error and quadratic phase error caused by nonlinear antenna trajectories. Position and Orientation System (POS) data is applied to acquiring accuracy motion attitudes and spatial positions of antenna phase centre (APC). In this paper, extend chirp scaling algorithm (ECS) is used to deal with echo data of airborne SAR. An experiment is done using VV-Polarization raw data of C-band airborne SAR. The quality evaluations of compensated SAR images and uncompensated SAR images are done in the experiment. The former always performs better than the latter. After MOCO processing, azimuth ambiguity is declined, peak side lobe ratio (PSLR) effectively improves and the resolution of images is improved obviously. The result shows the validity and operability of the imaging process for airborne SAR.

  8. MM wave SAR sensor design: Concept for an airborne low level reconnaissance system

    NASA Astrophysics Data System (ADS)

    Boesswetter, C.

    1986-07-01

    The basic system design considerations for a high resolution SAR system operating at 35 GHz or 94 GHz are given. First it is shown that only the focussed SAR concept in the side looking configuration matches the requirements and constraints. After definition of illumination geometry and airborne modes the fundamental SAR parameters in range and azimuth direction are derived. A review of the performance parameters of some critical mm wave components (coherent pulsed transmitters, front ends, antennas) establish the basis for further analysis. The power and contrast budget in the processed SAR image shows the feasibility of a 35/94 GHz SAR sensor design. The discussion of the resulting system parameters points out that this unusual system design implies both benefits and new risk areas. One of the benefits besides the compactness of sensor hardware turns out to be the short synthetic aperture length simplifying the design of the digital SAR processor, preferably operating in real time. A possible architecture based on current state-of-the-art correlator hardware is shown. One of the potential risk areas in achieving high resolution SAR imagery in the mm wave frequency band is motion compensation. However, it is shown that the short range and short synthetic aperture lengths ease the problem so that correction of motion induced phase errors and thus focussed synthetic aperture processing should be possible.

  9. Semi-physical Simulation of the Airborne InSAR based on Rigorous Geometric Model and Real Navigation Data

    NASA Astrophysics Data System (ADS)

    Changyong, Dou; Huadong, Guo; Chunming, Han; yuquan, Liu; Xijuan, Yue; Yinghui, Zhao

    2014-03-01

    Raw signal simulation is a useful tool for the system design, mission planning, processing algorithm testing, and inversion algorithm design of Synthetic Aperture Radar (SAR). Due to the wide and high frequent variation of aircraft's trajectory and attitude, and the low accuracy of the Position and Orientation System (POS)'s recording data, it's difficult to quantitatively study the sensitivity of the key parameters, i.e., the baseline length and inclination, absolute phase and the orientation of the antennas etc., of the airborne Interferometric SAR (InSAR) system, resulting in challenges for its applications. Furthermore, the imprecise estimation of the installation offset between the Global Positioning System (GPS), Inertial Measurement Unit (IMU) and the InSAR antennas compounds the issue. An airborne interferometric SAR (InSAR) simulation based on the rigorous geometric model and real navigation data is proposed in this paper, providing a way for quantitatively studying the key parameters and for evaluating the effect from the parameters on the applications of airborne InSAR, as photogrammetric mapping, high-resolution Digital Elevation Model (DEM) generation, and surface deformation by Differential InSAR technology, etc. The simulation can also provide reference for the optimal design of the InSAR system and the improvement of InSAR data processing technologies such as motion compensation, imaging, image co-registration, and application parameter retrieval, etc.

  10. EARSEC SAR processing system

    NASA Astrophysics Data System (ADS)

    Protheroe, Mark; Sloggett, David R.; Sieber, Alois J.

    1994-12-01

    Traditionally, the production of high quality Synthetic Aperture Radar imagery has been an area where a potential user would have to expend large amounts of money in either the bespoke development of a processing chain dedicated to his requirements or in the purchase of a dedicated hardware platform adapted using accelerator boards and enhanced memory management. Whichever option the user adopted there were limitations based on the desire for a realistic throughput in data load and time. The user had a choice, made early in the purchase, for either a system that adopted innovative algorithmic manipulation, to limit the processing time of the purchase of expensive hardware. The former limits the quality of the product, while the latter excludes the user from any visibility into the processing chain. Clearly there was a need for a SAR processing architecture that gave the user a choice into the methodology to be adopted for a particular processing sequence, allowing him to decide on either a quick (lower quality) product or a detailed slower (high quality) product, without having to change the algorithmic base of his processor or the hardware platform. The European Commission, through the Advanced Techniques unit of the Joint Research Centre (JRC) Institute for Remote Sensing at Ispra in Italy, realizing the limitations on current processing abilities, initiated its own program to build airborne SAR and Electro-Optical (EO) sensor systems. This program is called the European Airborne Remote Sensing Capabilities (EARSEC) program. This paper describes the processing system developed for the airborne SAR sensor system. The paper considers the requirements for the system and the design of the EARSEC Airborne SAR Processing System. It highlights the development of an open SAR processing architecture where users have full access to intermediate products that arise from each of the major processing stages. It also describes the main processing stages in the overall

  11. Hybrid space-airborne bistatic SAR geometric resolutions

    NASA Astrophysics Data System (ADS)

    Moccia, Antonio; Renga, Alfredo

    2009-09-01

    Performance analysis of Bistatic Synthetic Aperture Radar (SAR) characterized by arbitrary geometric configurations is usually complex and time-consuming since system impulse response has to be evaluated by bistatic SAR processing. This approach does not allow derivation of general equations regulating the behaviour of image resolutions with varying the observation geometry. It is well known that for an arbitrary configuration of bistatic SAR there are not perpendicular range and azimuth directions, but the capability to produce an image is not prevented as it depends only on the possibility to generate image pixels from time delay and Doppler measurements. However, even if separately range and Doppler resolutions are good, bistatic SAR geometries can exist in which imaging capabilities are very poor when range and Doppler directions become locally parallel. The present paper aims to derive analytical tools for calculating the geometric resolutions of arbitrary configuration of bistatic SAR. The method has been applied to a hybrid bistatic Synthetic Aperture Radar formed by a spaceborne illuminator and a receiving-only airborne forward-looking Synthetic Aperture Radar (F-SAR). It can take advantage of the spaceborne illuminator to dodge the limitations of monostatic FSAR. Basic modeling and best illumination conditions have been detailed in the paper.

  12. Initial assessment of an airborne Ku-band polarimetric SAR.

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

    Raynal, Ann Marie; Doerry, Armin Walter

    2013-02-01

    Polarimetric synthetic aperture radar (SAR) has been used for a variety of dual-use research applications since the 1940s. By measuring the direction of the electric field vector from radar echoes, polarimetry may enhance an analysts understanding of scattering effects for both earth monitoring and tactical surveillance missions. Polarimetry may provide insight into surface types, materials, or orientations for natural and man-made targets. Polarimetric measurements may also be used to enhance the contrast between scattering surfaces such as man-made objects and their surroundings. This report represents an initial assessment of the utility of, and applications for, polarimetric SAR at Ku-band formore » airborne or unmanned aerial systems.« less

  13. Airborne and Maritime/Fixed Station Joint Tactical Radio System (AMF JTRS)

    DTIC Science & Technology

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-421 Airborne & Maritime/Fixed Station Joint Tactical Radio System (AMF JTRS) As of FY 2017...Information Program Name Airborne & Maritime/Fixed Station Joint Tactical Radio System (AMF JTRS) DoD Component Army Responsible Office References SAR...UNCLASSIFIED 5 Mission and Description Airborne & Maritime/Fixed Station Joint Tactical Radio System (AMF JTRS) products are software programmable

  14. An Accurate Co-registration Method for Airborne Repeat-pass InSAR

    NASA Astrophysics Data System (ADS)

    Dong, X. T.; Zhao, Y. H.; Yue, X. J.; Han, C. M.

    2017-10-01

    Interferometric Synthetic Aperture Radar (InSAR) technology plays a significant role in topographic mapping and surface deformation detection. Comparing with spaceborne repeat-pass InSAR, airborne repeat-pass InSAR solves the problems of long revisit time and low-resolution images. Due to the advantages of flexible, accurate, and fast obtaining abundant information, airborne repeat-pass InSAR is significant in deformation monitoring of shallow ground. In order to getting precise ground elevation information and interferometric coherence of deformation monitoring from master and slave images, accurate co-registration must be promised. Because of side looking, repeat observing path and long baseline, there are very different initial slant ranges and flight heights between repeat flight paths. The differences of initial slant ranges and flight height lead to the pixels, located identical coordinates on master and slave images, correspond to different size of ground resolution cells. The mismatching phenomenon performs very obvious on the long slant range parts of master image and slave image. In order to resolving the different sizes of pixels and getting accurate co-registration results, a new method is proposed based on Range-Doppler (RD) imaging model. VV-Polarization C-band airborne repeat-pass InSAR images were used in experiment. The experiment result shows that the proposed method leads to superior co-registration accuracy.

  15. Monitoring of viable airborne SARS virus in ambient air

    NASA Astrophysics Data System (ADS)

    Agranovski, Igor E.; Safatov, Alexander S.; Pyankov, Oleg V.; Sergeev, Alexander N.; Agafonov, Alexander P.; Ignatiev, Georgy M.; Ryabchikova, Elena I.; Borodulin, Alexander I.; Sergeev, Artemii A.; Doerr, Hans W.; Rabenau, Holger F.; Agranovski, Victoria

    Due to recent SARS related issues (Science 300 (5624) 1394; Nature 423 (2003) 240; Science 300 (5627) 1966), the development of reliable airborne virus monitoring procedures has become galvanized by an exceptional sense of urgency and is presently in a high demand (In: Cox, C.S., Wathers, C.M. (Eds.), Bioaerosols Handbook, Lewis Publishers, Boca Raton, FL, 1995, pp. 247-267). Based on engineering control method (Aerosol Science and Technology 31 (1999) 249; 35 (2001) 852), which was previously applied to the removal of particles from gas carriers, a new personal bioaerosol sampler has been developed. Contaminated air is bubbled through porous medium submerged into liquid and subsequently split into multitude of very small bubbles. The particulates are scavenged by these bubbles, and, thus, effectively removed. The current study explores its feasibility for monitoring of viable airborne SARS virus. It was found that the natural decay of such virus in the collection fluid was around 0.75 and 1.76 lg during 2 and 4 h of continuous operation, respectively. Theoretical microbial recovery rates of higher than 55 and 19% were calculated for 1 and 2 h of operation, respectively. Thus, the new sampling method of direct non-violent collection of viable airborne SARS virus into the appropriate liquid environment was found suitable for monitoring of such stress sensitive virus.

  16. Vegetation canopy discrimination and biomass assessment using multipolarized airborne SAR

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T.; Dobson, M. C.; Held, D. N.

    1985-01-01

    Multipolarized airborne Synthetic Aperture Radar (SAR) data were acquired over a largely agricultural test site near Macomb, Illinois, in conjunction with the Shuttle Imaging Radar (SIR-B) experiment in October 1984. The NASA/JPL L-band SAR operating at 1.225 GHz made a series of daily overflights with azimuth view angles both parallel and orthogonal to those of SIR-B. The SAR data was digitally recorded in the quadpolarization configuration. An extensive set of ground measurements were obtained throughout the test site and include biophysical and soil measurements of approximately 400 agricultural fields. Preliminary evaluation of some of the airborne SAR imagery indicates a great potential for crop discrimination and assessment of canopy condition. False color composites constructed from the combination of three linear polarizations (HH, VV, and HV) were found to be clearly superior to any single polarization for purposes of crop classification. In addition, an image constructed using the HH return to modulate intensity and the phase difference between HH and VV returns to modulate chroma indicates a clear capability for assessment of canopy height and/or biomass. In particular, corn fields heavily damaged by infestations of corn borer are readily distinguished from noninfested fields.

  17. Image quality specification and maintenance for airborne SAR

    NASA Astrophysics Data System (ADS)

    Clinard, Mark S.

    2004-08-01

    Specification, verification, and maintenance of image quality over the lifecycle of an operational airborne SAR begin with the specification for the system itself. Verification of image quality-oriented specification compliance can be enhanced by including a specification requirement that a vendor provide appropriate imagery at the various phases of the system life cycle. The nature and content of the imagery appropriate for each stage of the process depends on the nature of the test, the economics of collection, and the availability of techniques to extract the desired information from the data. At the earliest lifecycle stages, Concept and Technology Development (CTD) and System Development and Demonstration (SDD), the test set could include simulated imagery to demonstrate the mathematical and engineering concepts being implemented thus allowing demonstration of compliance, in part, through simulation. For Initial Operational Test and Evaluation (IOT&E), imagery collected from precisely instrumented test ranges and targets of opportunity consisting of a priori or a posteriori ground-truthed cultural and natural features are of value to the analysis of product quality compliance. Regular monitoring of image quality is possible using operational imagery and automated metrics; more precise measurements can be performed with imagery of instrumented scenes, when available. A survey of image quality measurement techniques is presented along with a discussion of the challenges of managing an airborne SAR program with the scarce resources of time, money, and ground-truthed data. Recommendations are provided that should allow an improvement in the product quality specification and maintenance process with a minimal increase in resource demands on the customer, the vendor, the operational personnel, and the asset itself.

  18. Tomographic Imaging of a Forested Area By Airborne Multi-Baseline P-Band SAR.

    PubMed

    Frey, Othmar; Morsdorf, Felix; Meier, Erich

    2008-09-24

    In recent years, various attempts have been undertaken to obtain information about the structure of forested areas from multi-baseline synthetic aperture radar data. Tomographic processing of such data has been demonstrated for airborne L-band data but the quality of the focused tomographic images is limited by several factors. In particular, the common Fourierbased focusing methods are susceptible to irregular and sparse sampling, two problems, that are unavoidable in case of multi-pass, multi-baseline SAR data acquired by an airborne system. In this paper, a tomographic focusing method based on the time-domain back-projection algorithm is proposed, which maintains the geometric relationship between the original sensor positions and the imaged target and is therefore able to cope with irregular sampling without introducing any approximations with respect to the geometry. The tomographic focusing quality is assessed by analysing the impulse response of simulated point targets and an in-scene corner reflector. And, in particular, several tomographic slices of a volume representing a forested area are given. The respective P-band tomographic data set consisting of eleven flight tracks has been acquired by the airborne E-SAR sensor of the German Aerospace Center (DLR).

  19. Present and Future Airborne and Space-borne Systems

    DTIC Science & Technology

    2007-02-01

    Present and Future Airborne and Space-borne Systems Wolfgang Keydel Microwaves and Radar Institute German Aerospace Research Centre (DLR...airborne and space-borne SAR systems with polarimetric interferometry capability, their technological, system technical and application related...interferometry accuracies in the cm range have been obtained. In order to reach these values an exact system calibration is indispensable. The calibration of

  20. Cross-calibration between airborne SAR sensors

    NASA Technical Reports Server (NTRS)

    Zink, Manfred; Olivier, Philippe; Freeman, Anthony

    1993-01-01

    As Synthetic Aperture Radar (SAR) system performance and experience in SAR signature evaluation increase, quantitative analysis becomes more and more important. Such analyses require an absolute radiometric calibration of the complete SAR system. To keep the expenditure on calibration of future multichannel and multisensor remote sensing systems (e.g., X-SAR/SIR-C) within a tolerable level, data from different tracks and different sensors (channels) must be cross calibrated. The 1989 joint E-SAR/DC-8 SAR calibration campaign gave a first opportunity for such an experiment, including cross sensor and cross track calibration. A basic requirement for successful cross calibration is the stability of the SAR systems. The calibration parameters derived from different tracks and the polarimetric properties of the uncalibrated data are used to describe this stability. Quality criteria for a successful cross calibration are the agreement of alpha degree values and the consistency of radar cross sections of equally sized corner reflectors. Channel imbalance and cross talk provide additional quality in case of the polarimetric DC-8 SAR.

  1. 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.

  2. Airborne precursor missions in support of SIR-C/X-SAR

    NASA Technical Reports Server (NTRS)

    Evans, D.; Oettl, H.; Pampaloni, P.

    1991-01-01

    The NASA DC-8 and DLR E-SAR airborne imaging radars have been deployed over several sites in Europe and the U.S. in support of SIR-C/X-SAR (Shuttle Imaging Radar-C/X-Synthetic Aperture Radar) science team investigations. To date, data have been acquired in support of studies of alpine glaciers, forests, geology, oceanography, and calibration. An experimental campaign with airborne sensors will take place in Europe in June to July 1991 which will allow multitemporal surveys of several Europeans sites. Current plans are for calibration and ecology experiments to be undertaken in Germany, the Netherlands, Italy, France, and the United Kingdom. Coordinated multitemporal aircraft and ground campaigns are planned in support of hydrology experiments in Italy, the United Kingdom, and Austria. Data will also be acquired in support of oceanogrqhy in the Gulf of Genova, North Atlantic, Straits of Messina and the North Sea. Geology sites will include Campi Flegrei and Vesuvio, Italy.

  3. Battlefield radar imaging through airborne millimetric wave SAR (Synthetic Aperture Radar)

    NASA Astrophysics Data System (ADS)

    Carletti, U.; Daddio, E.; Farina, A.; Morabito, C.; Pangrazi, R.; Studer, F. A.

    Airborne synthetic aperture radar (SAR), operating in the millimetric-wave (mmw) region, is discussed with reference to a battlefield surveillance application. The SAR system provides high resolution real-time imaging of the battlefield and moving target detection, under adverse environmental conditions (e.g., weather, dust, smoke, obscurants). The most relevant and original aspects of the system are the band of operation (i.e., mmw in lieu of the more traditional microwave region) and the use of an unmanned platform. The former implies reduced weight and size requirements, thus allowing use of small unmanned platforms. The latter enchances the system operational effectiveness by permitting accomplishment of recognition missions in depth beyond the FEBA. An overall system architecture based on the onboard sensor, the platform, the communication equipment, and a mobile ground station is described. The main areas of ongoing investigation are presented: the simulation of the end-to-end system, and the critical technological issues such as mmw antenna, transmitter, signal processor for image formation and platform attitude errors compensation and detection and imaging of moving targets.

  4. Radar signatures of road vehicles: airborne SAR experiments

    NASA Astrophysics Data System (ADS)

    Palubinskas, G.; Runge, H.; Reinartz, P.

    2005-10-01

    The German radar satellite TerraSAR-X is a high resolution, dual receive antenna SAR satellite, which will be launched in spring 2006. Since it will have the capability to measure the velocity of moving targets, the acquired interferometric data can be useful for traffic monitoring applications on a global scale. DLR has started already the development of an automatic and operational processing system which will detect cars, measure their speed and assign them to a road. Statistical approaches are used to derive the vehicle detection algorithm, which require the knowledge of the radar signatures of vehicles, especially under consideration of the geometry of the radar look direction and the vehicle orientation. Simulation of radar signatures is a very difficult task due to the lack of realistic models of vehicles. In this paper the radar signatures of the parking cars are presented. They are estimated experimentally from airborne E-SAR X-band data, which have been collected during flight campaigns in 2003-2005. Several test cars of the same type placed in carefully selected orientation angles and several over-flights with different heading angles made it possible to cover the whole range of aspect angles from 0° to 180°. The large synthetic aperture length or beam width angle of 7° can be divided into several looks. Thus processing of each look separately allows to increase the angle resolution. Such a radar signature profile of one type of vehicle over the whole range of aspect angles in fine resolution can be used further for the verification of simulation studies and for the performance prediction for traffic monitoring with TerraSAR-X.

  5. An Open Source Software and Web-GIS Based Platform for Airborne SAR Remote Sensing Data Management, Distribution and Sharing

    NASA Astrophysics Data System (ADS)

    Changyong, Dou; Huadong, Guo; Chunming, Han; Ming, Liu

    2014-03-01

    With more and more Earth observation data available to the community, how to manage and sharing these valuable remote sensing datasets is becoming an urgent issue to be solved. The web based Geographical Information Systems (GIS) technology provides a convenient way for the users in different locations to share and make use of the same dataset. In order to efficiently use the airborne Synthetic Aperture Radar (SAR) remote sensing data acquired in the Airborne Remote Sensing Center of the Institute of Remote Sensing and Digital Earth (RADI), Chinese Academy of Sciences (CAS), a Web-GIS based platform for airborne SAR data management, distribution and sharing was designed and developed. The major features of the system include map based navigation search interface, full resolution imagery shown overlaid the map, and all the software adopted in the platform are Open Source Software (OSS). The functions of the platform include browsing the imagery on the map navigation based interface, ordering and downloading data online, image dataset and user management, etc. At present, the system is under testing in RADI and will come to regular operation soon.

  6. 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.

  7. Extracting Tree Height from Repeat-Pass PolInSAR Data : Experiments with JPL and ESA Airborne Systems

    NASA Technical Reports Server (NTRS)

    Lavalle, Marco; Ahmed, Razi; Neumann, Maxim; Hensley, Scott

    2013-01-01

    In this paper we present our latest developments and experiments with the random-motion-over-ground (RMoG) model used to extract canopy height and other important forest parameters from repeat-pass polarimetricinterferometric SAR (Pol-InSAR) data. More specifically, we summarize the key features of the RMoG model in contrast with the random-volume-over-ground (RVoG) model, describe in detail a possible inversion scheme for the RMoG model and illustrate the results of the RMoG inversion using airborne data collected by the Jet Propulsion Laboratory (JPL) and the European Space Agency (ESA).

  8. Retrieving current and wind vectors from ATI SAR data: airborne evidence and inversion strategy

    NASA Astrophysics Data System (ADS)

    Martin, Adrien; Gommenginger, Christine; Chapron, Bertrand; Marquez, José; Doody, Sam

    2017-04-01

    Conventional and along-track interferometric (ATI) Synthetic Aperture Radar (SAR) sense the motion of the ocean surface by measuring the Doppler shift of reflected signals. Together with the water displacement associated with ocean currents, the SAR measurements are also affected by a Wind-wave induced Artefact Surface Velocity (WASV) caused by the velocity of Bragg scatterers and the orbital velocity of ocean surface gravity waves. The WASV has been modelled theoretically in past studies but has been estimated empirically only once using Envisat ASAR. Here we propose, firstly, to evaluate this WASV from airborne ATI SAR data, secondly, to validate the airborne retrieved surface current after correction of the WASV against HF radar measurements and thirdly to examine the best inversion strategy for a an Ocean Surface Current (OSC) satellite mission to retrieve accurately both the ocean surface current vector (OSCV) and the wind vector in the frame of an OSC satellite mission. The airborne ATI SAR data were acquired in the tidally dominated Irish Sea using a Wavemill-type dual-beam SAR interferometer. A comprehensive collection of airborne Wavemill data acquired in a star pattern over a well-instrumented site made it possible to estimate the magnitude and dependence on azimuth and incidence angle of the WASV. The airborne results compare favourably with those reported for Envisat ASAR, empirical model, which has been used to correct for it. Validation of the current retrieval capabilities of the proof-of-concept has been conducted against HF radar giving a precisions typically better than 0.1 m/s for surface current speed and 7° for direction. Comparisons with POLCOMS (1.8 km) indicate that the model reproduces well the overall temporal evolution but does not capture the high spatial variability of ocean surface currents at the maximum ebb flow. Airborne retrieved currents highlight a short-scale spatial variability up to 100m related to bathymetry channels, which

  9. Airborne Multi-Band SAR in the Arctic

    NASA Astrophysics Data System (ADS)

    Gardner, J. M.; Brozena, J. M.; Liang, R.; Ball, D.; Holt, B.; Thomson, J.

    2016-12-01

    As one component of the Office of Naval Research supported Sea State Departmental Research Initiative during October of 2015 the Naval Research Laboratory flew an ultrawide-band, low-frequency, polarimetric SAR over the southward advancing sea ice in Beaufort Sea. The flights were coordinated with the research team aboard the R/V Sikuliaq working near and in the advancing pack ice. The majority of the SAR data were collected with the L-Band sensor (1000-1500 MHz) from an altitude of 10,000', providing a useful swath 6 km wide with 75o and 25 o angles of incidence at the inner and outer edge of the swath respectively. Some data were also collected with the P-Band SAR (215-915 MHz). The extremely large bandwidths allowed for formation of image pixels as small as 30 cm, however, we selected 60 cm pixel size to reduce image speckle. The separate polarimetric images are calibrated to one pixel to allow for calculations such as polarimetric decompositions that require the images to be well aligned. Both frequencies are useful particularly for the detection of ridges and areas of deformed ice. There are advantages and disadvantages to airborne SAR imagery compared to satellites. The chief advantages being the enormous allowable bandwidth leading to very fine range resolution, and the ability to fly arbitrary trajectories on demand. The latter permits specific areas to be imaged at a given time with a specified illumination direction. An area can even be illuminated from all directions by flying a circular trajectory around the target area. This captures ice features that are sensitive to illumination direction such as cracks, sastrugi orientation, and ridges. The disadvantages include variation of intensity across the swath with range and incidence angle. In addition to the SAR data, we collected photogrammetric imagery from a DSS-439, scanning lidar from a Riegl Q560 and surface brightness temperatures from a KT-19. However, since all of these sensors are nadir pointing

  10. Experimental L-Band Airborne SAR for Oil Spill Response at Sea and in Coastal Waters

    PubMed Central

    Jones, Cathleen E.; Holt, Benjamin

    2018-01-01

    Satellite synthetic aperture radar (SAR) is frequently used during oil spill response efforts to identify oil slick extent, but suffers from the major disadvantages of potential long latency between when a spill occurs and when a satellite can image the site and an inability to continuously track the spill as it develops. We show using data acquired with the Uninhabited Aerial Vehicle SAR (UAVSAR) instrument how a low noise, high resolution, L-band SAR could be used for oil spill response, with specific examples of tracking slick extent, position and weathering; determining zones of relatively thicker or more emulsified oil within a slick; and identifying oil slicks in coastal areas where look-alikes such as calm waters or biogenic slicks can confound the identification of mineral oil spills. From these key points, the essential features of an airborne SAR system for operational oil spill response are described, and further research needed to determine SAR’s capabilities and limitations in quantifying slick thickness is discussed. PMID:29470391

  11. Extracting DEM from airborne X-band data based on PolInSAR

    NASA Astrophysics Data System (ADS)

    Hou, X. X.; Huang, G. M.; Zhao, Z.

    2015-06-01

    Polarimetric Interferometric Synthetic Aperture Radar (PolInSAR) is a new trend of SAR remote sensing technology which combined polarized multichannel information and Interferometric information. It is of great significance for extracting DEM in some regions with low precision of DEM such as vegetation coverage area and building concentrated area. In this paper we describe our experiments with high-resolution X-band full Polarimetric SAR data acquired by a dual-baseline interferometric airborne SAR system over an area of Danling in southern China. Pauli algorithm is used to generate the double polarimetric interferometry data, Singular Value Decomposition (SVD), Numerical Radius (NR) and Phase diversity (PD) methods are used to generate the full polarimetric interferometry data. Then we can make use of the polarimetric interferometric information to extract DEM with processing of pre filtering , image registration, image resampling, coherence optimization, multilook processing, flat-earth removal, interferogram filtering, phase unwrapping, parameter calibration, height derivation and geo-coding. The processing system named SARPlore has been exploited based on VC++ led by Chinese Academy of Surveying and Mapping. Finally compared optimization results with the single polarimetric interferometry, it has been observed that optimization ways can reduce the interferometric noise and the phase unwrapping residuals, and improve the precision of DEM. The result of full polarimetric interferometry is better than double polarimetric interferometry. Meanwhile, in different terrain, the result of full polarimetric interferometry will have a different degree of increase.

  12. Airborne Science personnel Walter Klein and David Bushman at the Mission Manager's console onboard NASA's DC-8 during the AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-03

    Airborne Science personnel Walter Klein and David Bushman at the Mission Manager's console onboard NASA's DC-8 during the AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  13. Mapping tectonic and anthropogenic processes in central California using satellite and airborne InSAR

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Lundgren, P.; Liang, C.; Farr, T. G.; Fielding, E. J.

    2017-12-01

    The improved spatiotemporal resolution of surface deformation from recent satellite and airborne InSAR measurements provides a great opportunity to improve our understanding of both tectonic and non-tectonic processes. In central California the primary plate boundary fault system (San Andreas fault) lies adjacent to the San Joaquin Valley (SJV), a vast structural trough that accounts for about one-sixth of the United Sates' irrigated land and one-fifth of its extracted groundwater. The central San Andreas fault (CSAF) displays a range of fault slip behavior with creeping in its central segment that decreases towards its northwest and southeast ends, where it transitions to being fully locked. Despite much progress, many questions regarding fault and anthropogenic processes in the region still remain. In this study, we combine satellite InSAR and NASA airborne UAVSAR data to image fault and anthropogenic deformation. The UAVSAR data cover fault perpendicular swaths imaged from opposing look directions and fault parallel swaths since 2009. The much finer spatial resolution and optimized viewing geometry provide important constraints on near fault deformation and fault slip at very shallow depth. We performed a synoptic InSAR time series analysis using Sentinel-1, ALOS, and UAVSAR interferograms. We estimate azimuth mis-registration between single look complex (SLC) images of Sentinel-1 in a stack sense to achieve accurate azimuth co-registration between SLC images for low coherence and/or long interval interferometric pairs. We show that it is important to correct large-scale ionosphere features in ALOS-2 ScanSAR data for accurate deformation measurements. Joint analysis of UAVSAR and ALOS interferometry measurements show clear variability in deformation along the fault strike, suggesting variable fault creep and locking at depth and along strike. In addition to fault creep, the L-band ALOS, and especially ALOS-2 ScanSAR interferometry, show large-scale ground

  14. In Situ Soil Moisture and Thaw Depth Measurements Coincident with Airborne SAR Data Collections, Barrow and Seward Peninsulas, Alaska, 2017

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

    Cathy Wilson; Julian Dann; Robert Bolton

    The in-situ soil moisture and thaw depth measurements provided in this dataset were collected coincident with airborne overflights of L- and P-band SAR instruments at the NGEE Arctic study site near Barrow, on the North Slope, and at the three study sites on the Seward Peninsula, Alaska. Field measurements and flights were conducted during the summer of 2017 as a collaboration between the NASA ABoVE Project's Airborne SAR Campaign and the NGEE Arctic Project. ABoVE protocols for establishing field measurement plots were followed.

  15. Airborne Warning and Control System Block 40/45 Upgrade (AWACS Blk 40/45 Upgrade)

    DTIC Science & Technology

    2015-12-01

    Selected Acquisition Report ( SAR ) RCS: DD-A&T(Q&A)823-277 Airborne Warning and Control System Block 40/45 Upgrade (AWACS Blk 40/45 Upgrade) As of...Upgrade December 2015 SAR March 23, 2016 16:04:37 UNCLASSIFIED 2 Table of Contents Common Acronyms and Abbreviations for MDAP Programs 3 Program...Acquisition Unit Cost AWACS Blk 40/45 Upgrade December 2015 SAR March 23, 2016 16:04:37 UNCLASSIFIED 3 PB - President’s Budget PE - Program Element

  16. Airborne remote sensing of forest biomes

    NASA Technical Reports Server (NTRS)

    Sader, Steven A.

    1987-01-01

    Airborne sensor data of forest biomes obtained using an SAR, a laser profiler, an IR MSS, and a TM simulator are presented and examined. The SAR was utilized to investigate forest canopy structures in Mississippi and Costa Rica; the IR MSS measured forest canopy temperatures in Oregon and Puerto Rico; the TM simulator was employed in a tropical forest in Puerto Rico; and the laser profiler studied forest canopy characteristics in Costa Rica. The advantages and disadvantages of airborne systems are discussed. It is noted that the airborne sensors provide measurements applicable to forest monitoring programs.

  17. Software for Generating Strip Maps from SAR Data

    NASA Technical Reports Server (NTRS)

    Hensley, Scott; Michel, Thierry; Madsen, Soren; Chapin, Elaine; Rodriguez, Ernesto

    2004-01-01

    Jurassicprok is a computer program that generates strip-map digital elevation models and other data products from raw data acquired by an airborne synthetic-aperture radar (SAR) system. This software can process data from a variety of airborne SAR systems but is designed especially for the GeoSAR system, which is a dual-frequency (P- and X-band), single-pass interferometric SAR system for measuring elevation both at the bare ground surface and top of the vegetation canopy. Jurassicprok is a modified version of software developed previously for airborne-interferometric- SAR applications. The modifications were made to accommodate P-band interferometric processing, remove approximations that are not generally valid, and reduce processor-induced mapping errors to the centimeter level. Major additions and other improvements over the prior software include the following: a) A new, highly efficient multi-stage-modified wave-domain processing algorithm for accurately motion compensating ultra-wideband data; b) Adaptive regridding algorithms based on estimated noise and actual measured topography to reduce noise while maintaining spatial resolution; c) Exact expressions for height determination from interferogram data; d) Fully calibrated volumetric correlation data based on rigorous removal of geometric and signal-to-noise decorrelation terms; e) Strip range-Doppler image output in user-specified Doppler coordinates; f) An improved phase-unwrapping and absolute-phase-determination algorithm; g) A more flexible user interface with many additional processing options; h) Increased interferogram filtering options; and i) Ability to use disk space instead of random- access memory for some processing steps.

  18. Global Rapid Flood Mapping System with Spaceborne SAR Data

    NASA Astrophysics Data System (ADS)

    Yun, S. H.; Owen, S. E.; Hua, H.; Agram, P. S.; Fattahi, H.; Liang, C.; Manipon, G.; Fielding, E. J.; Rosen, P. A.; Webb, F.; Simons, M.

    2017-12-01

    As part of the Advanced Rapid Imaging and Analysis (ARIA) project for Natural Hazards, at NASA's Jet Propulsion Laboratory and California Institute of Technology, we have developed an automated system that produces derived products for flood extent map generation using spaceborne SAR data. The system takes user's input of area of interest polygons and time window for SAR data search (pre- and post-event). Then the system automatically searches and downloads SAR data, processes them to produce coregistered SAR image pairs, and generates log amplitude ratio images from each pair. Currently the system is automated to support SAR data from the European Space Agency's Sentinel-1A/B satellites. We have used the system to produce flood extent maps from Sentinel-1 SAR data for the May 2017 Sri Lanka floods, which killed more than 200 people and displaced about 600,000 people. Our flood extent maps were delivered to the Red Cross to support response efforts. Earlier we also responded to the historic August 2016 Louisiana floods in the United States, which claimed 13 people's lives and caused over $10 billion property damage. For this event, we made synchronized observations from space, air, and ground in close collaboration with USGS and NOAA. The USGS field crews acquired ground observation data, and NOAA acquired high-resolution airborne optical imagery within the time window of +/-2 hours of the SAR data acquisition by JAXA's ALOS-2 satellite. The USGS coordinates of flood water boundaries were used to calibrate our flood extent map derived from the ALOS-2 SAR data, and the map was delivered to FEMA for estimating the number of households affected. Based on the lessons learned from this response effort, we customized the ARIA system automation for rapid flood mapping and developed a mobile friendly web app that can easily be used in the field for data collection. Rapid automatic generation of SAR-based global flood maps calibrated with independent observations from

  19. Dr. Tom Mace, DFRC Director of Airborne Sciences, greets NASA Administrator Sean O'Keefe as he enters the DC-8 aircraft during a stop-off on the AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-03

    Dr. Tom Mace, NASA DFRC Director of Airborne Sciences, greets NASA Administrator Sean O'Keefe as he enters the DC-8 aircraft during a stop-off on the AirSAR 2004 Mesoamerica campaign. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  20. Classification of fully polarimetric F-SAR ( X / S ) airborne radar images using decomposition methods. (Polish Title: Klasyfikacja treści polarymetrycznych obrazów radarowych z wykorzystaniem metod dekompozycji na przykładzie systemu F-SAR ( X / S ))

    NASA Astrophysics Data System (ADS)

    Mleczko, M.

    2014-12-01

    Polarimetric SAR data is not widely used in practice, because it is not yet available operationally from the satellites. Currently we can distinguish two approaches in POL - In - SAR technology: alternating polarization imaging (Alt - POL) and fully polarimetric (QuadPol). The first represents a subset of another and is more operational, while the second is experimental because classification of this data requires polarimetric decomposition of scattering matrix in the first stage. In the literature decomposition process is divided in two types: the coherent and incoherent decomposition. In this paper the decomposition methods have been tested using data from the high resolution airborne F - SAR system. Results of classification have been interpreted in the context of the land cover mapping capabilities

  1. 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.

  2. 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.

  3. The need for separate operational and engineering user interfaces for command and control of airborne synthetic aperture radar systems

    NASA Astrophysics Data System (ADS)

    Klein, Laura M.; McNamara, Laura A.

    2017-05-01

    In this paper, we address the needed components to create usable engineering and operational user interfaces (UIs) for airborne Synthetic Aperture Radar (SAR) systems. As airborne SAR technology gains wider acceptance in the remote sensing and Intelligence, Surveillance, and Reconnaissance (ISR) communities, the need for effective and appropriate UIs to command and control these sensors has also increased. However, despite the growing demand for SAR in operational environments, the technology still faces an adoption roadblock, in large part due to the lack of effective UIs. It is common to find operational interfaces that have barely grown beyond the disparate tools engineers and technologists developed to demonstrate an initial concept or system. While sensor usability and utility are common requirements to engineers and operators, their objectives for interacting with the sensor are different. As such, the amount and type of information presented ought to be tailored to the specific application.

  4. Advanced Antenna Design for NASA's EcoSAR Instrument

    NASA Technical Reports Server (NTRS)

    Du Toit, Cornelis F.; Deshpande, Manohar; Rincon, Rafael F.

    2016-01-01

    Advanced antenna arrays were designed for NASA's EcoSAR airborne radar instrument. EcoSAR is a beamforming synthetic aperture radar instrument designed to make polarimetric and "single pass" interferometric measurements of Earth surface parameters. EcoSAR's operational requirements of a 435MHz center frequency with up to 200MHz bandwidth, dual polarization, high cross-polarization isolation (> 30 dB), +/- 45deg beam scan range and antenna form-factor constraints imposed stringent requirements on the antenna design. The EcoSAR project successfully developed, characterized, and tested two array antennas in an anechoic chamber. EcoSAR's first airborne campaign conducted in the spring of 2014 generated rich data sets of scientific and engineering value, demonstrating the successful operation of the antennas.

  5. A Novel Azimuth Super-Resolution Method by Synthesizing Azimuth Bandwidth of Multiple Tracks of Airborne Stripmap SAR Data

    PubMed Central

    Wang, Yan; Li, Jingwen; Sun, Bing; Yang, Jian

    2016-01-01

    Azimuth resolution of airborne stripmap synthetic aperture radar (SAR) is restricted by the azimuth antenna size. Conventionally, a higher azimuth resolution should be achieved by employing alternate modes that steer the beam in azimuth to enlarge the synthetic antenna aperture. However, if a data set of a certain region, consisting of multiple tracks of airborne stripmap SAR data, is available, the azimuth resolution of specific small region of interest (ROI) can be conveniently improved by a novel azimuth super-resolution method as introduced by this paper. The proposed azimuth super-resolution method synthesize the azimuth bandwidth of the data selected from multiple discontinuous tracks and contributes to a magnifier-like function with which the ROI can be further zoomed in with a higher azimuth resolution than that of the original stripmap images. Detailed derivation of the azimuth super-resolution method, including the steps of two-dimensional dechirping, residual video phase (RVP) removal, data stitching and data correction, is provided. The restrictions of the proposed method are also discussed. Lastly, the presented approach is evaluated via both the single- and multi-target computer simulations. PMID:27304959

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  7. Validation of Distributed Soil Moisture: Airborne Polarimetric SAR vs. Ground-based Sensor Networks

    NASA Astrophysics Data System (ADS)

    Jagdhuber, T.; Kohling, M.; Hajnsek, I.; Montzka, C.; Papathanassiou, K. P.

    2012-04-01

    The knowledge of spatially distributed soil moisture is highly desirable for an enhanced hydrological modeling in terms of flood prevention and for yield optimization in combination with precision farming. Especially in mid-latitudes, the growing agricultural vegetation results in an increasing soil coverage along the crop cycle. For a remote sensing approach, this vegetation influence has to be separated from the soil contribution within the resolution cell to extract the actual soil moisture. Therefore a hybrid decomposition was developed for estimation of soil moisture under vegetation cover using fully polarimetric SAR data. The novel polarimetric decomposition combines a model-based decomposition, separating the volume component from the ground components, with an eigen-based decomposition of the two ground components into a surface and a dihedral scattering contribution. Hence, this hybrid decomposition, which is based on [1,2], establishes an innovative way to retrieve soil moisture under vegetation. The developed inversion algorithm for soil moisture under vegetation cover is applied on fully polarimetric data of the TERENO campaign, conducted in May and June 2011 for the Rur catchment within the Eifel/Lower Rhine Valley Observatory. The fully polarimetric SAR data were acquired in high spatial resolution (range: 1.92m, azimuth: 0.6m) by DLR's novel F-SAR sensor at L-band. The inverted soil moisture product from the airborne SAR data is validated with corresponding distributed ground measurements for a quality assessment of the developed algorithm. The in situ measurements were obtained on the one hand by mobile FDR probes from agricultural fields near the towns of Merzenhausen and Selhausen incorporating different crop types and on the other hand by distributed wireless sensor networks (SoilNet clusters) from a grassland test site (near the town of Rollesbroich) and from a forest stand (within the Wüstebach sub-catchment). Each SoilNet cluster

  8. Combined Use of Airborne Lidar and DBInSAR Data to Estimate LAI in Temperate Mixed Forests

    NASA Technical Reports Server (NTRS)

    Peduzzi, Alicia; Wynne, Randolph Hamilton; Thomas, Valerie A.; Nelson, Ross F.; Reis, James J.; Sanford, Mark

    2012-01-01

    The objective of this study was to determine whether leaf area index (LAI) in temperate mixed forests is best estimated using multiple-return airborne laser scanning (lidar) data or dual-band, single-pass interferometric synthetic aperture radar data (from GeoSAR) alone, or both in combination. In situ measurements of LAI were made using the LiCor LAI-2000 Plant Canopy Analyzer on 61 plots (21 hardwood, 36 pine, 4 mixed pine hardwood; stand age ranging from 12-164 years; mean height ranging from 0.4 to 41.2 m) in the Appomattox-Buckingham State Forest, Virginia, USA. Lidar distributional metrics were calculated for all returns and for ten one meter deep crown density slices (a new metric), five above and five below the mode of the vegetation returns for each plot. GeoSAR metrics were calculated from the X-band backscatter coefficients (four looks) as well as both X- and P-band interferometric heights and magnitudes for each plot. Lidar metrics alone explained 69% of the variability in LAI, while GeoSAR metrics alone explained 52%. However, combining the lidar and GeoSAR metrics increased the R2 to 0.77 with a CV-RMSE of 0.42. This study indicates the clear potential for X-band backscatter and interferometric height (both now available from spaceborne sensors), when combined with small-footprint lidar data, to improve LAI estimation in temperate mixed forests.

  9. Topographic mapping using a monopulse SAR system

    NASA Technical Reports Server (NTRS)

    Zink, M.; Oettl, H.; Freeman, A.

    1993-01-01

    Terrain height variations in mountainous areas cause two problems in the radiometric correction of SAR images: the first being that the wrong elevation angle may be used in correcting for the radiometric variation of the antenna pattern; the second that the local incidence angle used in correcting the projection of the pixel area from slant range to ground range coordinates may vary from that given by the flat earth assumption. We propose a novel design of a SAR system which exploits the monopulse principle to determine the elevation angle and thus the height at the different parts of the image. The key element of such a phase monopulse system is an antenna, which can be divided into a lower and upper half in elevation using a monopulse comparator. In addition to the usual sum pattern, the elevation difference pattern can be generated by a -pi phase shift on one half of the antenna. From the ratios of images radiometrically modulated by the difference and sum antenna pattern in cross-track direction, we can derive the appropriate elevation angle at any point in the image. Together with the slant range we can calculate the height of the platform above this point using information on the antenna pointing and the platform attitude. This operation, repeated at many locations throughout the image, allows us to build up a topographic map of the height of the aircraft above each location. Inversion of this map, using the precisely determined aircraft altitude and the accurate flight path, leads to the actual topography of the imaged surface. The precise elevation of one point in the image could also be used to convert the height map to a topographic map. In this paper, we present design considerations for a corresponding airborne SAR system in X-Band and give estimates of the error due to system noise and azimuth ambiguities as well as the expected performance and precision in topographic mapping.

  10. Detection and Identification of Archaeological Sites and Features Using Synthetic Aperture Radar (SAR) Data Collected from Airborne Platforms

    DTIC Science & Technology

    2006-04-26

    sessions were used not only for signature development, but more 5 immediately to determine the spatial precision of images produced from...algorithms (e.g., NDVI and Tasseled Cap) available. The most instructive vectors were determined to be the SAR band polarizations vertically in the C...lands. Our principal, but not exclusive, focus has been on the use of high resolution airborne radar data in detection. in’<l’entoxy, and

  11. JPL Researcher Bruce Chapman at an AirSAR station aboard NASA's DC-8 flying laboratory during the AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-03

    JPL Researcher Bruce Chapman at an AirSAR station aboard NASA's DC-8 flying laboratory during the AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  12. School children from Punta Arenas, Chile, talk with Dr. David Imel, an AirSAR scientist from NASA JPL, during AirSAR 2004

    NASA Image and Video Library

    2004-03-10

    School children from Punta Arenas, Chile, talk with Dr. David Imel, an AirSAR scientist from NASA JPL, during AirSAR 2004. AirSAR 2004 is a three-week expedition by an international team of scientists that uses an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central and South America with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. In South America and Antarctica, AirSAR collected imagery and data to help determine the contribution of Southern Hemisphere glaciers to sea level rise due to climate change. In Patagonia, researchers found this contribution had more than doubled from 1995 to 2000, compared to the previous 25 years. AirSAR data will make it possible to determine whether that trend is continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  13. JPL Researcher Tim Miller at the primary AirSAR station aboard NASA's DC-8 flying laboratory during the AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-03

    JPL Researcher Tim Miller at the primary AirSAR station aboard NASA's DC-8 flying laboratory during the AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  14. The flight test of Pi-SAR(L) for the repeat-pass interferometric SAR

    NASA Astrophysics Data System (ADS)

    Nohmi, Hitoshi; Shimada, Masanobu; Miyawaki, Masanori

    2006-09-01

    This paper describes the experiment of the repeat pass interferometric SAR using Pi-SAR(L). The air-borne repeat-pass interferometric SAR is expected as an effective method to detect landslide or predict a volcano eruption. To obtain a high-quality interferometric image, it is necessary to make two flights on the same flight pass. In addition, since the antenna of the Pi-SAR(L) is secured to the aircraft, it is necessary to fly at the same drift angle to keep the observation direction same. We built a flight control system using an auto pilot which has been installed in the airplane. This navigation system measures position and altitude precisely with using a differential GPS, and the PC Navigator outputs a difference from the desired course to the auto pilot. Since the air density is thinner and the speed is higher than the landing situation, the gain of the control system is required to be adjusted during the repeat pass flight. The observation direction could be controlled to some extent by adjusting a drift angle with using a flight speed control. The repeat-pass flight was conducted in Japan for three days in late November. The flight was stable and the deviation was within a few meters for both horizontal and vertical direction even in the gusty condition. The SAR data were processed in time domain based on range Doppler algorism to make the complete motion compensation. Thus, the interferometric image processed after precise phase compensation is shown.

  15. Chirp Scaling Algorithms for SAR Processing

    NASA Technical Reports Server (NTRS)

    Jin, M.; Cheng, T.; Chen, M.

    1993-01-01

    The chirp scaling SAR processing algorithm is both accurate and efficient. Successful implementation requires proper selection of the interval of output samples, which is a function of the chirp interval, signal sampling rate, and signal bandwidth. Analysis indicates that for both airborne and spaceborne SAR applications in the slant range domain a linear chirp scaling is sufficient. To perform nonlinear interpolation process such as to output ground range SAR images, one can use a nonlinear chirp scaling interpolator presented in this paper.

  16. UAVSAR and TerraSAR-X Based InSAR Detection of Localized Subsidence in the New Orleans Area

    NASA Astrophysics Data System (ADS)

    Blom, R. G.; An, K.; Jones, C. E.; Latini, D.

    2014-12-01

    Vulnerability of the US Gulf coast to inundation has received increased attention since hurricanes Katrina and Rita. Compounding effects of sea level rise, wetland loss, and regional and local subsidence makes flood protection a difficult challenge, and particularly for the New Orleans area. Key to flood protection is precise knowledge of elevations and elevation changes. Analysis of historical and continuing geodetic measurements show surprising complexity, including locations subsiding more rapidly than considered during planning of hurricane protection and coastal restoration projects. Combining traditional, precise geodetic data with interferometric synthetic aperture radar (InSAR) observations can provide geographically dense constraints on surface deformation. The Gulf Coast environment is challenging for InSAR techniques, especially with systems not designed for interferometry. We use two InSAR capable systems, the L- band (24 cm wavelength) airborne JPL/NASA UAVSAR, and the DLR/EADS Astrium spaceborne TerraSAR X-band (3 cm wavelength), and compare results. First, we are applying pair-wise InSAR to the longer wavelength UAVSAR data to detect localized elevation changes potentially impacting flood protection infrastructure from 2009 - 2014. We focus on areas on and near flood protection infrastructure to identify changes indicative of subsidence, structural deformation, and/or seepage. The Spaceborne TerraSAR X-band SAR system has relatively frequent observations, and dense persistent scatterers in urban areas, enabling measurement of very small displacements. We compare L-band UAVSAR results with permanent scatterer (PS-InSAR) and Short Baseline Subsets (SBAS) interferometric analyses of a stack composed by 28 TerraSAR X-band images acquired over the same period. Thus we can evaluate results from the different radar frequencies and analyses techniques. Preliminary results indicate subsidence features potentially of a variety of causes, including ground water

  17. Optimization of Turkish Air Force SAR Units Forward Deployment Points for a Central Based SAR Force Structure

    DTIC Science & Technology

    2015-03-26

    Turkish Airborne Early Warning and Control (AEW& C ) aircraft in the combat arena. He examines three combat scenarios Turkey might encounter to cover and...to limited SAR assets, constrained budgets, logistic- maintenance problems, and high risk level of military flights. In recent years, the Turkish Air...model, Set Covering Location Problem (SCLP), defines the minimum number of SAR DPs to cover all fighter aircraft training areas (TAs). The second

  18. Processing of polarimetric SAR data for soil moisture estimation over Mahantango watershed area

    NASA Technical Reports Server (NTRS)

    Rao, K. S.; Teng, W. L.; Wang, J. R.

    1992-01-01

    Microwave remote sensing technique has a high potential for measuring soil moisture due to the large contrast in dielectric constant of dry and wet soils. Recent work by Pults et al. demonstrated the use of X/C-band data for quantitative surface soil moisture extraction from Airborne Synthetic Aperture Radar (SAR) system. Similar technique was adopted using polarimetric SAR data acquired with the JPL-AIRSAR system over the Mahantango watershed area in central Pennsylvania during July 1990. The data sets reported include C-, L-, and P-bands of 10, 13, 15, and 17 July 1990.

  19. Advanced Algorithms and High-Performance Testbed for Large-Scale Site Characterization and Subsurface Target Detecting Using Airborne Ground Penetrating SAR

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Collier, James B.; Citak, Ari

    1997-01-01

    A team of US Army Corps of Engineers, Omaha District and Engineering and Support Center, Huntsville, let Propulsion Laboratory (JPL), Stanford Research Institute (SRI), and Montgomery Watson is currently in the process of planning and conducting the largest ever survey at the Former Buckley Field (60,000 acres), in Colorado, by using SRI airborne, ground penetrating, Synthetic Aperture Radar (SAR). The purpose of this survey is the detection of surface and subsurface Unexploded Ordnance (UXO) and in a broader sense the site characterization for identification of contaminated as well as clear areas. In preparation for such a large-scale survey, JPL has been developing advanced algorithms and a high-performance restbed for processing of massive amount of expected SAR data from this site. Two key requirements of this project are the accuracy (in terms of UXO detection) and speed of SAR data processing. The first key feature of this testbed is a large degree of automation and a minimum degree of the need for human perception in the processing to achieve an acceptable processing rate of several hundred acres per day. For accurate UXO detection, novel algorithms have been developed and implemented. These algorithms analyze dual polarized (HH and VV) SAR data. They are based on the correlation of HH and VV SAR data and involve a rather large set of parameters for accurate detection of UXO. For each specific site, this set of parameters can be optimized by using ground truth data (i.e., known surface and subsurface UXOs). In this paper, we discuss these algorithms and their successful application for detection of surface and subsurface anti-tank mines by using a data set from Yuma proving Ground, A7, acquired by SRI SAR.

  20. VIP tour of NASA DFRC's DC-8 during the AirSAR 2004 Mesoamerica campaign

    NASA Image and Video Library

    2004-03-03

    VIP tour of NASA DFRC's DC-8 airborne laboratory during the AirSAR 2004 Mesoamerica campaign given by Craig Dobson, NASA Program Manager for AirSAR, L-R: Dr. Sonia Marta Mora, President of the Costa Rican National Rector’s Council; NASA Administrator Sean O'Keefe; Fernando Gutierrez, Costa Rican Minister of Science and Technology(MICIT); Mr. John Danilovich, US Ambassador to Costa Rica; and Dobson. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  1. A penguin near Punta Arena, Chile, photographed in its natural summer habitat during NASA's AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-13

    A penguin near Punta Arena, Chile, photographed in its natural summer habitat during NASA's AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct.

  2. Airborne relay-based regional positioning system.

    PubMed

    Lee, Kyuman; Noh, Hongjun; Lim, Jaesung

    2015-05-28

    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.

  3. 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

  4. Estimation of penetration of forest canopies by Interferometric SAR measurements

    NASA Technical Reports Server (NTRS)

    Rodriguez, Ernesto; Michel, Thierry R.; Harding, David J.

    1995-01-01

    In contrast to traditional Synthetic Aperture Radar (SAR), an Interferometric SAR (INSAR) yields two additional measurements: the phase difference and the correlation between the two interferometric channels. The phase difference has been used to estimate topographic height. For homogeneous surfaces, the correlation depends on the system signal-to-noise (SNR) ratio, the interferometer parameters, and the local slope. In the presence of volume scattering, such as that encountered in vegetation canopies, the correlation between the two channels is also dependent on the degree of penetration of the radiation into the scattering medium. In this paper, we propose a method for removing system and slope effects in order to obtain the decorrelation due to penetration alone. The sensitivities and accuracy of the proposed method are determined by Monte Carlo experiments, and we show that the proposed technique has sufficient sensitivity to provide penetration measurements for airborne SAR systems. Next, we provide a theoretical model to estimate the degree of penetration in a way which is independent of the details of the scattering medium. We also present a model for the correlation from non-homogeneous layers. We assess the sensitivity of the proposed inversion technique to these inhomogeneous situations. Finally, we present a comparison of the interferometric results against in situ data obtained by an airborne laser profilometer which provides a direct measurement of tree height and an estimate of the vegetation density profile in the forested areas around Mt. Adams, WA.

  5. A fox at Torres del Paine National Park in Chile during NASA's AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-11

    A fox at Torres del Paine National Park in Chile during NASA's AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. Founded in 1959, Torres del Paine National Park encompasses 450,000 acres in the Patagonia region of Chile. This region is being studied by NASA using a DC-8 equipped with an Airborne Synthetic Aperture Radar (AirSAR) developed by scientists from NASA’s Jet Propulsion Laboratory. This is a very sensitive region that is important to scientists because the temperature has been consistently rising causing a subsequent melting of the region’s glaciers. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  6. ARBRES: Light-Weight CW/FM SAR Sensors for Small UAVs

    PubMed Central

    Aguasca, Albert; Acevo-Herrera, Rene; Broquetas, Antoni; Mallorqui, Jordi J.; Fabregas, Xavier

    2013-01-01

    This paper describes a pair of compact CW/FM airborne SAR systems for small UAV-based operation (wingspan of 3.5 m) for low-cost testing of innovative SAR concepts. Two different SAR instruments, using the C and X bands, have been developed in the context of the ARBRES project, each of them achieving a payload weight below 5 Kg and a volume of 13.5 dm3 (sensor and controller). Every system has a dual receiving channel which allows operation in interferometric or polarimetric modes. Planar printed array antennas are used in both sensors for easy system integration and better isolation between transmitter and receiver subsystems. First experimental tests on board a 3.2 m wingspan commercial radio-controlled aircraft are presented. The SAR images of a field close to an urban area have been focused using a back-projection algorithm. Using the dual channel capability, a single pass interferogram and Digital Elevation Model (DEM) has been obtained which agrees with the scene topography. A simple Motion Compensation (MoCo) module, based on the information from an Inertial+GPS unit, has been included to compensate platform motion errors with respect to the nominal straight trajectory. PMID:23467032

  7. Personnel viewing AirSAR hardware while touring the outside of NASA's DC-8 during a stop-off on the AirSAR 2004 Mesoamerica campaign

    NASA Image and Video Library

    2004-03-03

    Personnel viewing AirSAR hardware while touring the outside of NASA's DC-8 during a stop-off on the AirSAR 2004 Mesoamerica campaign, L-R: Fernando Gutierrez, Costa Rican Minister of Science and Technology(MICIT); NASA Administrator Sean O'Keefe; Dr. Gahssem Asrar, NASA Associate Administrator for Earth Science Enterprises; JPL scientist Bruce Chapman; and Craig Dobson, NASA Program Manager for AirSAR. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

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

    DOEpatents

    Deaton, Juan D [Menan, ID; Schmitt, Michael J [Idaho Falls, ID; Jones, Warren F [Idaho Falls, ID

    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.

  9. 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

  10. Calibration of a polarimetric imaging SAR

    NASA Technical Reports Server (NTRS)

    Sarabandi, K.; Pierce, L. E.; Ulaby, F. T.

    1991-01-01

    Calibration of polarimetric imaging Synthetic Aperture Radars (SAR's) using point calibration targets is discussed. The four-port network calibration technique is used to describe the radar error model. The polarimetric ambiguity function of the SAR is then found using a single point target, namely a trihedral corner reflector. Based on this, an estimate for the backscattering coefficient of the terrain is found by a deconvolution process. A radar image taken by the JPL Airborne SAR (AIRSAR) is used for verification of the deconvolution calibration method. The calibrated responses of point targets in the image are compared both with theory and the POLCAL technique. Also, response of a distributed target are compared using the deconvolution and POLCAL techniques.

  11. Evaluation of Airborne l- Band Multi-Baseline Pol-Insar for dem Extraction Beneath Forest Canopy

    NASA Astrophysics Data System (ADS)

    Li, W. M.; Chen, E. X.; Li, Z. Y.; Jiang, C.; Jia, Y.

    2018-04-01

    DEM beneath forest canopy is difficult to extract with optical stereo pairs, InSAR and Pol-InSAR techniques. Tomographic SAR (TomoSAR) based on different penetration and view angles could reflect vertical structure and ground structure. This paper aims at evaluating the possibility of TomoSAR for underlying DEM extraction. Airborne L-band repeat-pass Pol-InSAR collected in BioSAR 2008 campaign was applied to reconstruct the 3D structure of forest. And sum of kronecker product and algebraic synthesis algorithm were used to extract ground structure, and phase linking algorithm was applied to estimate ground phase. Then Goldstein cut-branch approach was used to unwrap the phases and then estimated underlying DEM. The average difference between the extracted underlying DEM and Lidar DEM is about 3.39 m in our test site. And the result indicates that it is possible for underlying DEM estimation with airborne L-band repeat-pass TomoSAR technique.

  12. PRF Ambiguity Detrmination for Radarsat ScanSAR System

    NASA Technical Reports Server (NTRS)

    Jin, Michael Y.

    1998-01-01

    PRF ambiguity is a potential problem for a spaceborne SAR operated at high frequencies. For a strip mode SAR, there were several approaches to solve this problem. This paper, however, addresses PRF ambiguity determination algorithms suitable for a burst mode SAR system such as the Radarsat ScanSAR. The candidate algorithms include the wavelength diversity algorithm, range look cross correlation algorithm, and multi-PRF algorithm.

  13. Playback system designed for X-Band SAR

    NASA Astrophysics Data System (ADS)

    Yuquan, Liu; Changyong, Dou

    2014-03-01

    SAR(Synthetic Aperture Radar) has extensive application because it is daylight and weather independent. In particular, X-Band SAR strip map, designed by Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, provides high ground resolution images, at the same time it has a large spatial coverage and a short acquisition time, so it is promising in multi-applications. When sudden disaster comes, the emergency situation acquires radar signal data and image as soon as possible, in order to take action to reduce loss and save lives in the first time. This paper summarizes a type of X-Band SAR playback processing system designed for disaster response and scientific needs. It describes SAR data workflow includes the payload data transmission and reception process. Playback processing system completes signal analysis on the original data, providing SAR level 0 products and quick image. Gigabit network promises radar signal transmission efficiency from recorder to calculation unit. Multi-thread parallel computing and ping pong operation can ensure computation speed. Through gigabit network, multi-thread parallel computing and ping pong operation, high speed data transmission and processing meet the SAR radar data playback real time requirement.

  14. High-Level Performance Modeling of SAR Systems

    NASA Technical Reports Server (NTRS)

    Chen, Curtis

    2006-01-01

    SAUSAGE (Still Another Utility for SAR Analysis that s General and Extensible) is a computer program for modeling (see figure) the performance of synthetic- aperture radar (SAR) or interferometric synthetic-aperture radar (InSAR or IFSAR) systems. The user is assumed to be familiar with the basic principles of SAR imaging and interferometry. Given design parameters (e.g., altitude, power, and bandwidth) that characterize a radar system, the software predicts various performance metrics (e.g., signal-to-noise ratio and resolution). SAUSAGE is intended to be a general software tool for quick, high-level evaluation of radar designs; it is not meant to capture all the subtleties, nuances, and particulars of specific systems. SAUSAGE was written to facilitate the exploration of engineering tradeoffs within the multidimensional space of design parameters. Typically, this space is examined through an iterative process of adjusting the values of the design parameters and examining the effects of the adjustments on the overall performance of the system at each iteration. The software is designed to be modular and extensible to enable consideration of a variety of operating modes and antenna beam patterns, including, for example, strip-map and spotlight SAR acquisitions, polarimetry, burst modes, and squinted geometries.

  15. Airborne SAR determination of relative ages of Walker Valley moraines, eastern Sierra Nevada

    NASA Technical Reports Server (NTRS)

    Fox, A.; Isacks, B.; Bloom, A.; Fielding, E.; Mcmurry, D.

    1991-01-01

    A regional study of the distribution and elevations of Pleistocene moraines in the Andes requires a method of determining relative age from space. One of our primary objectives is to establish the relative chronology of major climatic events responsible for glaciation in the Andes and other regions that are difficult to access on the ground and where suitable material for absolute age determination is lacking. The sensitivity of radar to surface roughness makes it possible to develop a remotely-based relative dating technique for landforms for which surface age and roughness can be correlated. We are developing such a technique with Airborne Synthetic Aperture Radar (AIRSAR) imagery of the eastern Sierra Nevada where independent evidence is available for the ages and physical characteristics of moraines. The Sierra Nevada moraines are similar in form and environmental setting to Andean moraines that we have targeted for study during the pending Shuttle Imaging Radar-C (SIR-C) mission. SAR imagery is used to differentiate the ages of five moraine sequences of Walker Valley in the eastern Sierra Nevada. Other aspects of this investigation are briefly discussed.

  16. The Cuernos del Paine mountains in Torres del Paine National Park, Chile, during NASA's AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-11

    The Cuernos del Paine mountains in Torres del Paine National Park, Chile, during NASA's AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. Founded in 1959, Torres del Paine National Park encompasses 450,000 acres in the Patagonia region of Chile. This region is being studied by NASA using a DC-8 equipped with an Airborne Synthetic Aperture Radar (AirSAR) developed by scientists from NASA’s Jet Propulsion Laboratory. This is a very sensitive region that is important to scientists because the temperature has been consistently rising causing a subsequent melting of the region’s glaciers. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  17. Developing an interactive teleradiology system for SARS diagnosis

    NASA Astrophysics Data System (ADS)

    Sun, Jianyong; Zhang, Jianguo; Zhuang, Jun; Chen, Xiaomeng; Yong, Yuanyuan; Tan, Yongqiang; Chen, Liu; Lian, Ping; Meng, Lili; Huang, H. K.

    2004-04-01

    Severe acute respiratory syndrome (SARS) is a respiratory illness that had been reported in Asia, North America, and Europe in last spring. Most of the China cases of SARS have occurred by infection in hospitals or among travelers. To protect the physicians, experts and nurses from the SARS during the diagnosis and treatment procedures, the infection control mechanisms were built in SARS hospitals. We built a Web-based interactive teleradiology system to assist the radiologists and physicians both in side and out side control area to make image diagnosis. The system consists of three major components: DICOM gateway (GW), Web-based image repository server (Server), and Web-based DICOM viewer (Viewer). This system was installed and integrated with CR, CT and the hospital information system (HIS) in Shanghai Xinhua hospital to provide image-based ePR functions for SARS consultation between the radiologists, physicians and experts inside and out side control area. The both users inside and out side the control area can use the system to process and manipulate the DICOM images interactively, and the system provide the remote control mechanism to synchronize their operations on images and display.

  18. VIP group in hangar during AirSAR 2004 Mesoamerica campaign

    NASA Image and Video Library

    2004-03-03

    VIP group in hangar during AirSAR 2004 Mesoamerica campaign, L-R: Dr. Gahssem Asrar, NASA Associate Administrator for Earth Science Enterprises; Fernando Gutierrez, Costa Rican Minister of Science and Technology(MICIT); Jorge Andres Diaz, Director of the Costa Rican National Hangar for Airborne Research division of the National Center for High Technology(CENAT); Dr. Pedro Leon, General Director for the Costa Rican National Center for High Technology(CENAT); NASA Administrator Sean O'Keefe; Dr. Sonia Marta Mora, President of the Costa Rican National Rector’s Council(CONARE); Mr. John Danilovich, US Ambassador to Costa Rica; and unknown. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  19. Glacier Grey view from Lago Grey (Grey Lake), photographed during NASA's AirSAR 2004 campaign in Chile

    NASA Image and Video Library

    2004-03-11

    Glacier Grey view from Lago Grey (Grey Lake), photographed during NASA's AirSAR 2004 campaign in Chile. Land visible in this photo was covered by glacier just 6 years earlier. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. Founded in 1959, Torres del Paine National Park encompasses 450,000 acres in the Patagonia region of Chile. This region is being studied by NASA using a DC-8 equipped with an Airborne Synthetic Aperture Radar (AirSAR) developed by scientists from NASA’s Jet Propulsion Laboratory. This is a very sensitive region that is important to scientists because the temperature has been consistently rising causing a subsequent melting of the region’s glaciers. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  20. Calibration of quadpolarization SAR data using backscatter statistics

    NASA Technical Reports Server (NTRS)

    Klein, Jeffrey D.

    1989-01-01

    A new technique is described for calibration of complex multipolarization SAR imagery. Scatterer reciprocity and lack of correlation between like- and cross-polarized radar echoes for natural targets are used to remove cross-polarized contamination in the radar data channels without the use of known ground targets. If known targets are available, all data channels can be calibrated relative to one another and absolutely as well. The method is verified with airborne SAR data.

  1. A P-band SAR interference filter

    NASA Technical Reports Server (NTRS)

    Taylor, Victor B.

    1992-01-01

    The synthetic aperture radar (SAR) interference filter is an adaptive filter designed to reduce the effects of interference while minimizing the introduction of undesirable side effects. The author examines the adaptive spectral filter and the improvement in processed SAR imagery using this filter for Jet Propulsion Laboratory Airborne SAR (JPL AIRSAR) data. The quality of these improvements is determined through several data fidelity criteria, such as point-target impulse response, equivalent number of looks, SNR, and polarization signatures. These parameters are used to characterize two data sets, both before and after filtering. The first data set consists of data with the interference present in the original signal, and the second set consists of clean data which has been coherently injected with interference acquired from another scene.

  2. Ice cauldron formation during the initial phase of the Eyjafjallajökull eruption observed with an airborne SAR

    NASA Astrophysics Data System (ADS)

    Magnusson, E.; Gudmundsson, M. T.; Hognadottir, T.; Hoskuldsson, F.; Oddsson, B.

    2010-12-01

    We present images obtained by the Icelandic Coast Guard with an airborne Synthetic Aperture Radar (SAR) during the first hours and days of the subglacial eruption in Eyjafjallajökull. Cloud cover obscured the summit from view in the first three days of the eruption. Under these circumstances the SAR, being weather independent and able to see through ash plumes, was a particularly valuable tool. It provided a record of temporal development of ice cauldrons formed in the 200 m thick ice cover in the caldera, the 50-100 m thick ice on the southern slopes and disruption due to flooding in the northward facing outlet glacier Gígjökull. The eruption started 14 April, 2010, at 1:30 AM. The eruption apparently remained subglacial for some hours but a small plume was observed by aircraft around 6 AM. The first SAR radar images were obtained at 8:55 and a record of images obtained until 10:42 reveal the early development of ice cauldrons providing unique detail in how the eruption breaks new holes in the ice surface, allowing accurate estimates of ice melting rates in an explosive eruption. Widening of the cauldron around the most active crater on the first day of the eruption was 20-25 m/hour, indicating that heat transfer from magma to the ice walls of the cauldron was of order 2 x 106 W m-2. This heat transfer rate reduced fast as the cauldrons reached a width of 300-400 m. The eruption site was repeatedly surveyed with the same SAR during the next days. The images demonstrate how the surface cauldrons evolved and how the center of the eruption activity moved during the second day of the eruption. During the first days of the eruption holes formed in the surface of the Gígjökull glacier outlet, where the roof of flood water channels collapsed. The SAR images allows further understanding on the flood water mechanism by revealing that many of these holes were formed by an intensive flash flood on the second day of the eruption, presumably by hydraulic fracturing when

  3. The Ecosystems SAR (EcoSAR) an Airborne P-band Polarimetric InSAR for the Measurement of Vegetation Structure, Biomass and Permafrost

    NASA Technical Reports Server (NTRS)

    Rincon, Rafael F.; Fatoyinbo, Temilola; Ranson, K. Jon; Osmanoglu, Batuhan; Sun, Guoqing; Deshpande, Manohar D.; Perrine, Martin L.; Du Toit, Cornelis F.; Bonds, Quenton; Beck, Jaclyn; hide

    2014-01-01

    EcoSAR is a new synthetic aperture radar (SAR) instrument being developed at the NASA/ Goddard Space Flight Center (GSFC) for the polarimetric and interferometric measurements of ecosystem structure and biomass. The instrument uses a phased-array beamforming architecture and supports full polarimetric measurements and single pass interferometry. This Instrument development is part of NASA's Earth Science Technology Office Instrument Incubator Program (ESTO IIP).

  4. Use of SAR in Regional Methane Exchange Studies

    NASA Technical Reports Server (NTRS)

    Morrissey, L. A.; Livingston, G. P.; Durden, S. L.

    1994-01-01

    Significant sources of uncertainty in global trace gas budgets are due to lack of knowledge concerning the areal and temporal extent of source and sink areas. Synthetic aperture radar (SAR) is particularly suited to studies of northern ecosystems because of its all-weather operating capability which enables the acquisition of seasonal data. As key controls on methane exchange, the ability to differentiate major vegetation communities, inundation, and leaf area index (LAI) with satellite and airborne SAR data would increase the accuracy and precision of regional and seasonal estimates of methane exchange. The utility of SAR data for monitoring key controls on methane emissions from Arctic and boreal ecosystems is examined.

  5. SAR processing using SHARC signal processing systems

    NASA Astrophysics Data System (ADS)

    Huxtable, Barton D.; Jackson, Christopher R.; Skaron, Steve A.

    1998-09-01

    Synthetic aperture radar (SAR) is uniquely suited to help solve the Search and Rescue problem since it can be utilized either day or night and through both dense fog or thick cloud cover. Other papers in this session, and in this session in 1997, describe the various SAR image processing algorithms that are being developed and evaluated within the Search and Rescue Program. All of these approaches to using SAR data require substantial amounts of digital signal processing: for the SAR image formation, and possibly for the subsequent image processing. In recognition of the demanding processing that will be required for an operational Search and Rescue Data Processing System (SARDPS), NASA/Goddard Space Flight Center and NASA/Stennis Space Center are conducting a technology demonstration utilizing SHARC multi-chip modules from Boeing to perform SAR image formation processing.

  6. Sparsity-driven coupled imaging and autofocusing for interferometric SAR

    NASA Astrophysics Data System (ADS)

    Zengin, Oǧuzcan; Khwaja, Ahmed Shaharyar; ćetin, Müjdat

    2018-04-01

    We propose a sparsity-driven method for coupled image formation and autofocusing based on multi-channel data collected in interferometric synthetic aperture radar (IfSAR). Relative phase between SAR images contains valuable information. For example, it can be used to estimate the height of the scene in SAR interferometry. However, this relative phase could be degraded when independent enhancement methods are used over SAR image pairs. Previously, Ramakrishnan et al. proposed a coupled multi-channel image enhancement technique, based on a dual descent method, which exhibits better performance in phase preservation compared to independent enhancement methods. Their work involves a coupled optimization formulation that uses a sparsity enforcing penalty term as well as a constraint tying the multichannel images together to preserve the cross-channel information. In addition to independent enhancement, the relative phase between the acquisitions can be degraded due to other factors as well, such as platform location uncertainties, leading to phase errors in the data and defocusing in the formed imagery. The performance of airborne SAR systems can be affected severely by such errors. We propose an optimization formulation that combines Ramakrishnan et al.'s coupled IfSAR enhancement method with the sparsity-driven autofocus (SDA) approach of Önhon and Çetin to alleviate the effects of phase errors due to motion errors in the context of IfSAR imaging. Our method solves the joint optimization problem with a Lagrangian optimization method iteratively. In our preliminary experimental analysis, we have obtained results of our method on synthetic SAR images and compared its performance to existing methods.

  7. Airborne net-centric multi-INT sensor control, display, fusion, and exploitation systems

    NASA Astrophysics Data System (ADS)

    Linne von Berg, Dale C.; Lee, John N.; Kruer, Melvin R.; Duncan, Michael D.; Olchowski, Fred M.; Allman, Eric; Howard, Grant

    2004-08-01

    The NRL Optical Sciences Division has initiated a multi-year effort to develop and demonstrate an airborne net-centric suite of multi-intelligence (multi-INT) sensors and exploitation systems for real-time target detection and targeting product dissemination. The goal of this Net-centric Multi-Intelligence Fusion Targeting Initiative (NCMIFTI) is to develop an airborne real-time intelligence gathering and targeting system that can be used to detect concealed, camouflaged, and mobile targets. The multi-INT sensor suite will include high-resolution visible/infrared (EO/IR) dual-band cameras, hyperspectral imaging (HSI) sensors in the visible-to-near infrared, short-wave and long-wave infrared (VNIR/SWIR/LWIR) bands, Synthetic Aperture Radar (SAR), electronics intelligence sensors (ELINT), and off-board networked sensors. Other sensors are also being considered for inclusion in the suite to address unique target detection needs. Integrating a suite of multi-INT sensors on a single platform should optimize real-time fusion of the on-board sensor streams, thereby improving the detection probability and reducing the false alarms that occur in reconnaissance systems that use single-sensor types on separate platforms, or that use independent target detection algorithms on multiple sensors. In addition to the integration and fusion of the multi-INT sensors, the effort is establishing an open-systems net-centric architecture that will provide a modular "plug and play" capability for additional sensors and system components and provide distributed connectivity to multiple sites for remote system control and exploitation.

  8. NASA Administrator Sean O'Keefe speaking at the AirSAR 2004 Mesoamerica hangar naming ceremony

    NASA Image and Video Library

    2004-03-03

    NASA Administrator Sean O'Keefe speaking at the AirSAR 2004 Mesoamerica hangar naming ceremony. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  9. ISCE: A Modular, Reusable Library for Scalable SAR/InSAR Processing

    NASA Astrophysics Data System (ADS)

    Agram, P. S.; Lavalle, M.; Gurrola, E. M.; Sacco, G. F.; Rosen, P. A.

    2016-12-01

    Traditional community SAR/InSAR processing software tools have primarily focused on differential interferometry and Solid Earth applications. The InSAR Scientific Computing Environment (ISCE) was specifically designed to support the Earth Sciences user community as well as large scale operational processing tasks, thanks to its two-layered (Python+C/Fortran) architecture and modular framework. ISCE is freely distributed as a source tarball, allowing advanced users to modify and extend it for their research purposes and developing exploratory applications, while providing a relatively simple user interface for novice users to perform routine data analysis efficiently. Modular design of the ISCE library also enables easier development of applications to address the needs of Ecosystems, Cryosphere and Disaster Response communities in addition to the traditional Solid Earth applications. In this talk, we would like to emphasize the broader purview of the ISCE library and some of its unique features that sets it apart from other freely available community software like GMTSAR and DORIS, including: Support for multiple geometry regimes - Native Doppler (ALOS-1) as well Zero Doppler (ESA missions) systems. Support for data acquired by airborne platforms - e.g, JPL's UAVSAR and AirMOSS, DLR's F-SAR. Radiometric Terrain Correction - Auxiliary output layers from the geometry modules include projection angles, incidence angles, shadow-layover masks. Dense pixel offsets - Parallelized amplitude cross correlation for cryosphere / ionospheric correction applications. Rubber sheeting - Pixel-by-pixel offsets fields for resampling slave imagery for geometric co-registration/ ionospheric corrections. Preliminary Tandem-X processing support - Bistatic geometry modules. Extensibility to support other non-Solid Earth missions - Modules can be directly adopted for use with other SAR missions, e.g., SWOT. Preliminary support for multi-dimensional data products- multi-polarization, multi

  10. 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.

  11. 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.

  12. Fault and anthropogenic processes in central California constrained by satellite and airborne InSAR and in-situ observations

    NASA Astrophysics Data System (ADS)

    Liu, Zhen; Lundgren, Paul

    2016-07-01

    The San Andreas Fault (SAF) system is the primary plate boundary in California, with the central SAF (CSAF) lying adjacent to the San Joaquin Valley (SJV), a vast structural trough that accounts for about one-sixth of the United Sates' irrigated land and one-fifth of its extracted groundwater. The CSAF displays a range of fault slip behavior with creeping in its central segment that decreases towards its northwest and southeast ends, where the fault transitions to being fully locked. At least six Mw ~6.0 events since 1857 have occurred near the Parkfield transition, most recently in 2004. Large earthquakes also occurred on secondary faults parallel to the SAF, the result of distributed deformation across the plate boundary zone. Recent studies have revealed the complex interaction between anthropogenic related groundwater depletion and the seismic activity on adjacent faults through stress interaction. Despite recent progress, many questions regarding fault and anthropogenic processes in the region still remain. For example, how is the relative plate motion accommodated between the CSAF and off-fault deformation? What is the distribution of fault creep and slip deficit at shallow depths? What are the spatiotemporal variations of fault slip? What are the spatiotemporal characteristics of anthropogenic and lithospheric processes and how do they interact with each other? To address these, we combine satellite InSAR and NASA airborne UAVSAR data to image on and off-fault deformation. The UAVSAR data cover fault perpendicular swaths imaged from opposing look directions and fault parallel swaths since 2009. The much finer spatial resolution and optimized viewing geometry provide important constraints on near fault deformation and fault slip at very shallow depth. We performed a synoptic InSAR time series analysis using ERS-1/2, Envisat, ALOS and UAVSAR interferograms. The combined C-band ERS-1/2 and Envisat data provide a long time interval of SAR data over the region

  13. A butterfly photographed in the La Selva region of the Costa Rican rain forest as part of NASA's AirSAR 2004 Mesoamerica campaign

    NASA Image and Video Library

    2004-03-04

    A butterfly photographed in the La Selva region of the Costa Rican rain forest as part of NASA's AirSAR 2004 Mesoamerica campaign. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to do. NASA's AIRSAR technolgy provides two essential elements to the ground-based scientists. First, it tests and provides accurate measurements of the forest structure. Secondly, AirSAR can study a larger area of the forest versus the smaller area that can be tested and plotted by the ground scientists. It also provides a unique one-of-a-kind system of measurement that obtains important information for the scientists, such as where forests are located and what exactly is in them.

  14. A lizard photographed in the La Selva region of the Costa Rican rain forest as part of NASA's AirSAR 2004 Mesoamerica campaign

    NASA Image and Video Library

    2004-03-04

    A lizard photographed in the La Selva region of the Costa Rican rain forest as part of NASA's AirSAR 2004 Mesoamerica campaign. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to do. NASA's AIRSAR technolgy provides two essential elements to the ground-based scientists. First, it tests and provides accurate measurements of the forest structure. Secondly, AirSAR can study a larger area of the forest versus the smaller area that can be tested and plotted by the ground scientists. It also provides a unique one-of-a-kind system of measurement that obtains important information for the scientists, such as where forests are located and what exactly is in them.

  15. A plant photographed in the La Selva region of the Costa Rican rain forest as part of NASA's AirSAR 2004 Mesoamerica campaign

    NASA Image and Video Library

    2004-03-04

    A plant photographed in the La Selva region of the Costa Rican rain forest as part of NASA's AirSAR 2004 Mesoamerica campaign. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to do. NASA's AIRSAR technolgy provides two essential elements to the ground-based scientists. First, it tests and provides accurate measurements of the forest structure. Secondly, AirSAR can study a larger area of the forest versus the smaller area that can be tested and plotted by the ground scientists. It also provides a unique one-of-a-kind system of measurement that obtains important information for the scientists, such as where forests are located and what exactly is in them.

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

    USDA-ARS?s Scientific Manuscript database

    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. Close-up view of Grey Glacier from Lago Grey (Grey Lake), taken during NASA's AirSAR 2004 campaign in Chile

    NASA Image and Video Library

    2004-03-11

    Close-up view of Grey Glacier from Lago Grey (Grey Lake), taken during NASA's AirSAR 2004 campaign in Chile. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. Founded in 1959, Torres del Paine National Park encompasses 450,000 acres in the Patagonia region of Chile. This region is being studied by NASA using a DC-8 equipped with an Airborne Synthetic Aperture Radar (AirSAR) developed by scientists from NASA’s Jet Propulsion Laboratory. This is a very sensitive region that is important to scientists because the temperature has been consistently rising causing a subsequent melting of the region’s glaciers. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  18. A cave in Glacier Grey in Torres del Paine National Park, seen during NASA's AirSAR 2004 campaign in Chile

    NASA Image and Video Library

    2004-03-11

    A cave in Glacier Grey in Torres del Paine National Park, seen during NASA's AirSAR 2004 campaign in Chile. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. Founded in 1959, Torres del Paine National Park encompasses 450,000 acres in the Patagonia region of Chile. This region is being studied by NASA using a DC-8 equipped with an Airborne Synthetic Aperture Radar (AirSAR) developed by scientists from NASA’s Jet Propulsion Laboratory. This is a very sensitive region that is important to scientists because the temperature has been consistently rising causing a subsequent melting of the region’s glaciers. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  19. The Cuernos del Paine mountains in Torres del Paine National Park in Chile, photographed during NASA's AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-11

    The Cuernos del Paine mountains in Torres del Paine National Park in Chile, photographed during NASA's AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. Founded in 1959, Torres del Paine National Park encompasses 450,000 acres in the Patagonia region of Chile. This region is being studied by NASA using a DC-8 equipped with an Airborne Synthetic Aperture Radar (AirSAR) developed by scientists from NASA’s Jet Propulsion Laboratory. This is a very sensitive region that is important to scientists because the temperature has been consistently rising causing a subsequent melting of the region’s glaciers. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  20. Chilean Air Force Captain Saez and Dr. Tom Mace discuss airborne science during a DC-8 ferry flight from Santiago to Punta Arenas, Chile

    NASA Image and Video Library

    2004-03-10

    Chilean Air Force Captain Saez and Dr. Tom Mace, DFRC Director of Airborne Sciences, discuss airborne science during a DC-8 ferry flight from Santiago to Punta Arenas, Chile. AirSAR 2004 is a three-week expedition by an international team of scientists that uses an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central and South America with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. In South America and Antarctica, AirSAR collected imagery and data to help determine the contribution of Southern Hemisphere glaciers to sea level rise due to climate change. In Patagonia, researchers found this contribution had more than doubled from 1995 to 2000, compared to the previous 25 years. AirSAR data will make it possible to determine whether that trend is continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  1. Replacing missing data between airborne SAR coherent image pairs

    DOE PAGES

    Musgrove, Cameron H.; West, James C.

    2017-07-31

    For synthetic aperture radar systems, missing data samples can cause severe image distortion. When multiple, coherent data collections exist and the missing data samples do not overlap between collections, there exists the possibility of replacing data samples between collections. For airborne radar, the known and unknown motion of the aircraft prevents direct data sample replacement to repair image features. Finally, this paper presents a method to calculate the necessary phase corrections to enable data sample replacement using only the collected radar data.

  2. Replacing missing data between airborne SAR coherent image pairs

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

    Musgrove, Cameron H.; West, James C.

    For synthetic aperture radar systems, missing data samples can cause severe image distortion. When multiple, coherent data collections exist and the missing data samples do not overlap between collections, there exists the possibility of replacing data samples between collections. For airborne radar, the known and unknown motion of the aircraft prevents direct data sample replacement to repair image features. Finally, this paper presents a method to calculate the necessary phase corrections to enable data sample replacement using only the collected radar data.

  3. Investigation of the Capability of Compact Polarimetric SAR Interferometry to Estimate Forest Height

    NASA Astrophysics Data System (ADS)

    Zhang, Hong; Xie, Lei; Wang, Chao; Chen, Jiehong

    2013-08-01

    The main objective of this paper is to investigate the capability of compact Polarimetric SAR Interferometry (C-PolInSAR) on forest height estimation. For this, the pseudo fully polarimetric interferomteric (F-PolInSAR) covariance matrix is firstly reconstructed, then the three- stage inversion algorithm, hybrid algorithm, Music and Capon algorithm are applied to both C-PolInSAR covariance matrix and pseudo F-PolInSAR covariance matrix. The availability of forest height estimation is demonstrated using L-band data generated by simulator PolSARProSim and X-band airborne data acquired by East China Research Institute of Electronic Engineering, China Electronics Technology Group Corporation.

  4. A unique tree trunk photographed in La Selva region of the Costa Rican rain forest as part of NASA's AirSAR 2004 Mesoamerica campaign

    NASA Image and Video Library

    2004-03-04

    A unique tree trunk photographed in La Selva region of the Costa Rican rain forest as part of NASA's AirSAR 2004 Mesoamerica campaign. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to do. NASA's AIRSAR technolgy provides two essential elements to the ground-based scientists. First, it tests and provides accurate measurements of the forest structure. Secondly, AirSAR can study a larger area of the forest versus the smaller area that can be tested and plotted by the ground scientists. It also provides a unique one-of-a-kind system of measurement that obtains important information for the scientists, such as where forests are located and what exactly is in them.

  5. A tree frog photographed in the La Selva region of the Costa Rican rain forest as part of NASA's AirSAR 2004 Mesoamerica campaign

    NASA Image and Video Library

    2004-03-04

    A tree frog photographed in the La Selva region of the Costa Rican rain forest as part of NASA's AirSAR 2004 Mesoamerica campaign. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to do. NASA's AIRSAR technolgy provides two essential elements to the ground-based scientists. First, it tests and provides accurate measurements of the forest structure. Secondly, AirSAR can study a larger area of the forest versus the smaller area that can be tested and plotted by the ground scientists. It also provides a unique one-of-a-kind system of measurement that obtains important information for the scientists, such as where forests are located and what exactly is in them.

  6. This photograph shows a stream in the La Selva region of the Costa Rican rain forest, taken during NASA's AirSAR 2004 Mesoamerica campaign

    NASA Image and Video Library

    2004-03-04

    This photograph shows a stream in the La Selva region of the Costa Rican rain forest, taken during NASA's AirSAR 2004 Mesoamerica campaign. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to do. NASA's AIRSAR technolgy provides two essential elements to the ground-based scientists. First, it tests and provides accurate measurements of the forest structure. Secondly, AirSAR can study a larger area of the forest versus the smaller area that can be tested and plotted by the ground scientists. It also provides a unique one-of-a-kind system of measurement that obtains important information for the scientists, such as where forests are located and what exactly is in them.

  7. Reflectors used to calibrate the DC-8's AirSAR seen here setup in the Costa Rican rain forest by scientist Paul Siqueira from NASA’s Jet Propulsion Lab

    NASA Image and Video Library

    2004-03-05

    Reflectors setup in the La Selva region of the Costa Rican rain forest by scientist Paul Siqueira from NASA’s Jet Propulsion Lab. These reflectors are used by JPL scientists onboard Dryden's DC-8 aircraft to calibrate the Airborne Synthetic Aperture Radar (AirSAR) system. Scientists place these reflectors at known points on the ground, allowing researchers onboard the aircraft to verify their data. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that uses an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. The radar, developed by NASA's Jet Propulsion Laboratory, can penetrate clouds and also collect data at night. Its high-resolution sensors operate at multiple wavelengths and modes, allowing AirSAR to see beneath treetops, through thin sand, and dry snow pack. AirSAR's 2004 campaign is a collaboration of many U.S. and Central American institutions and scientists, including NASA; the National Science Foundation; the Smithsonian Institution; National Geographic; Conservation International; the Organization of Tropical Studies; the Central American Commission for Environment and Development; and the Inter-American Development Bank.

  8. Software For Calibration Of Polarimetric SAR Data

    NASA Technical Reports Server (NTRS)

    Van Zyl, Jakob; Zebker, Howard; Freeman, Anthony; Holt, John; Dubois, Pascale; Chapman, Bruce

    1994-01-01

    POLCAL (Polarimetric Radar Calibration) software tool intended to assist in calibration of synthetic-aperture radar (SAR) systems. In particular, calibrates Stokes-matrix-format data produced as standard product by NASA/Jet Propulsion Laboratory (JPL) airborne imaging synthetic aperture radar (AIRSAR). Version 4.0 of POLCAL is upgrade of version 2.0. New options include automatic absolute calibration of 89/90 data, distributed-target analysis, calibration of nearby scenes with corner reflectors, altitude or roll-angle corrections, and calibration of errors introduced by known topography. Reduces crosstalk and corrects phase calibration without use of ground calibration equipment. Written in FORTRAN 77.

  9. A tree trunk structure photographed in the La Selva region of the Costa Rican rain forest as part of NASA's AirSAR 2004 Mesoamerica campaign

    NASA Image and Video Library

    2004-03-04

    A tree trunk structure photographed in the La Selva region of the Costa Rican rain forest as part of NASA's AirSAR 2004 Mesoamerica campaign. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to do. NASA's AIRSAR technolgy provides two essential elements to the ground-based scientists. First, it tests and provides accurate measurements of the forest structure. Secondly, AirSAR can study a larger area of the forest versus the smaller area that can be tested and plotted by the ground scientists. It also provides a unique one-of-a-kind system of measurement that obtains important information for the scientists, such as where forests are located and what exactly is in them.

  10. David Bushman at the Mission Manager's console onboard NASA's DC-8 during the AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-03

    David Bushman at the Mission Manager's console onboard NASA's DC-8 during the AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  11. TerraSAR-X Measurements of Wind Fields, Ocean Waves and Currents

    NASA Astrophysics Data System (ADS)

    Lehner, S.; Schulz-Stellenfleth, J.; Brusch, S.

    2008-01-01

    TerraSAR-X is a new german X-band radar satellite launched on June 15, 2007. In this mission an operational spaceborne synthetic aperture radar (SAR) system with very high spatial resolution is set up producing remote sensing products for commercial and scientific use. TerraSAR-X is a scientific and technological continuation of the successful Space Shuttle missions SIR-C/X and SRTM.The spacecraft is equipped with a phased array X-band SAR, which can operate in different polarisations and has furthermore beam stearing capabilities. In addition the system has a split antenna mode, which is able to provide along track interferometric information. The instrument is designed for multiple imaging modes like Stripmap, Spotlight and ScanSAR.Due to its polarimetric and interferometric capabilities as well as the high spatial resolution of up to 1 m, the TerraSAR-X sensor is a very interesting tool for oceanography. The presentation will give an overview of several applications, which are of both scientific and commercial interest, like e.g. current and ocean wave measurements, monitoring of morphodynamical processes or high resolution wind field retrieval. The potential as well as limitations of the instrument will be summarized and compared with existing sensors. Necessary steps to translate existing C-band SAR inversion algorithms for wind and wave measurements to X-band will be discussed. A strategy will be outlined to achieve this by a combination of theoretical investigations and the use of existing experimental data acquired by both airborne and groundbased X-band radar. First results on the adaption of existing C-band wind retrieval algorithms will be presented. Wind and ocean wave parameter retrievals will be presented, e.g., based on TerraSAR-X scenes taken over the English channel.

  12. Role of fomites in SARS transmission during the largest hospital outbreak in Hong Kong.

    PubMed

    Xiao, Shenglan; Li, Yuguo; Wong, Tze-Wai; Hui, David S C

    2017-01-01

    The epidemic of severe acute respiratory syndrome (SARS) had a significant effect on global society in the early 2000s and the potential of its resurgence exists. Studies on the modes of transmission of SARS are limited though a number of outbreak studies have revealed the possible airborne route. To develop more specific and effective control strategies, we conducted a detailed mechanism-based investigation that explored the role of fomite transmission in the well-known Ward 8A outbreak. We considered three hypothetical transmission routes, i.e., the long-range airborne, fomite and combined routes, in 1,744 scenarios with combinations of some important parameters. A multi-agent model was used to predict the infection risk distributions of the three hypothetical routes. Model selection was carried out for different scenarios to compare the distributions of infection risk with that of the reported attack rates and select the hypotheses with the best fitness. Our results reveal that under the assumed conditions, the SARS coronavirus was most possible to have spread via the combined long-range airborne and fomite routes, and that the fomite route played a non-negligible role in the transmission.

  13. Calibration of complex polarimetric SAR imagery using backscatter correlations

    NASA Technical Reports Server (NTRS)

    Klein, Jeffrey D.

    1992-01-01

    A new technique for calibration of multipolarization synthetic aperture radar (SAR) imagery is described. If scatterer reciprocity and lack of correlation between co- and cross-polarized radar echoes (for azimuthally symmetric distributed targets) is assumed, the effects of signal leakage between the radar data channels can be removed without the use of known ground targets. If known targets are available, all data channels may be calibrated relative to one another and radiometrically as well. The method is verified with simulations and application to airborne SAR data.

  14. [Air-borne disease].

    PubMed

    Lameiro Vilariño, Carmen; del Campo Pérez, Victor M; Alonso Bürger, Susana; Felpeto Nodar, Irene; Guimarey Pérez, Rosa; Pérez Alvarellos, Alberto

    2003-11-01

    Respiratory protection is a factor which worries nursing professionals who take care of patients susceptible of transmitting microorganisms through the air more as every day passes. This type of protection covers the use of surgical or hygienic masks against the transmission of infection by airborne drops to the use of highly effective masks or respirators against the transmission of airborne diseases such as tuberculosis or SARS, a recently discovered disease. The adequate choice of this protective device and its correct use are fundamental in order to have an effective protection for exposed personnel. The authors summarize the main protective respiratory devices used by health workers, their characteristics and degree of effectiveness, as well as the circumstances under which each device is indicated for use.

  15. SAR Imagery Applied to the Monitoring of Hyper-Saline Deposits: Death Valley Example (CA)

    NASA Technical Reports Server (NTRS)

    Lasne, Yannick; Paillou, Philippe; Freeman, Anthony; Chapman, Bruce

    2009-01-01

    The present study aims at understanding the influence of salinity on the dielectric constant of soils and then on the backscattering coeff cients recorded by airborne/spaceborne SAR systems. Based on dielectric measurements performed over hyper-saline deposits in Death Valley (CA), as well as laboratory electromagnetic characterization of salts and water mixtures, we used the dielectric constants as input parameters of analytical IEM simulations to model both the amplitude and phase behaviors of SAR signal at C, and L-bands. Our analytical simulations allow to reproduce specif c copolar signatures recorded in SAR data, corresponding to the Cottonball Basin saltpan. We also propose the copolar backscattering ratio and phase difference as indicators of moistened and salt-affected soils. More precisely, we show that these copolar indicators should allow to monitor the seasonal variations of the dielectric properties of saline deposits.

  16. High Resolution SAR Imaging Employing Geometric Features for Extracting Seismic Damage of Buildings

    NASA Astrophysics Data System (ADS)

    Cui, L. P.; Wang, X. P.; Dou, A. X.; Ding, X.

    2018-04-01

    Synthetic Aperture Radar (SAR) image is relatively easy to acquire but difficult for interpretation. This paper probes how to identify seismic damage of building using geometric features of SAR. The SAR imaging geometric features of buildings, such as the high intensity layover, bright line induced by double bounce backscattering and dark shadow is analysed, and show obvious differences texture features of homogeneity, similarity and entropy in combinatorial imaging geometric regions between the un-collapsed and collapsed buildings in airborne SAR images acquired in Yushu city damaged by 2010 Ms7.1 Yushu, Qinghai, China earthquake, which implicates a potential capability to discriminate collapsed and un-collapsed buildings from SAR image. Study also shows that the proportion of highlight (layover & bright line) area (HA) is related to the seismic damage degree, thus a SAR image damage index (SARDI), which related to the ratio of HA to the building occupation are of building in a street block (SA), is proposed. While HA is identified through feature extraction with high-pass and low-pass filtering of SAR image in frequency domain. A partial region with 58 natural street blocks in the Yushu City are selected as study area. Then according to the above method, HA is extracted, SARDI is then calculated and further classified into 3 classes. The results show effective through validation check with seismic damage classes interpreted artificially from post-earthquake airborne high resolution optical image, which shows total classification accuracy 89.3 %, Kappa coefficient 0.79 and identical to the practical seismic damage distribution. The results are also compared and discussed with the building damage identified from SAR image available by other authors.

  17. Results of the 1989 experiment with a polarimetric multifrequency SAR

    NASA Astrophysics Data System (ADS)

    Groot, J. S.; Vandenbroek, A. C.

    1992-03-01

    In August 1989, a single day measurement campaign was conducted with two airborne imaging radars, the Dutch X band Side Looking Airborne Radar (SLAR) and the P/L/C band polarimetric Synthetic Aperture Radar (SAR). Test sites were the Flevopolder and the Veluwe (agricultural and forested areas, respectively) in the Netherlands. Ground activities included the deployment of several calibration devices like different sized trihedrals, dihedrals, and PARC's (active calibrators). An extensive experiment description is presented. Relevant details of the two radar systems and the calibration devices used are given. The calibration of the SLAR and SAR data is described. The calibrated data is used to investigate its potential for the classification of agricultural crop types. Several quantities are extracted from the data, which are used to do this. Examples are the copolarization phase difference distribution, the degree of polarization, and copolarized signatures. It appears to be quite possible to discriminate bare soil fields from vegetated fields using polarimetric quantities like the HH/VV (Horizontal Horizontal/Vertical Vertical) phase difference distribution and the degree of polarization. However, discrimination between fields with different crop types is much more difficult probably due to interference of features not related to the crop type, such as soil moisture, soil roughness, lodging, etc.

  18. An automatic target recognition system based on SAR image

    NASA Astrophysics Data System (ADS)

    Li, Qinfu; Wang, Jinquan; Zhao, Bo; Luo, Furen; Xu, Xiaojian

    2009-10-01

    In this paper, an automatic target recognition (ATR) system based on synthetic aperture radar (SAR) is proposed. This ATR system can play an important role in the simulation of up-to-data battlefield environment and be used in ATR research. To establish an integral and available system, the processing of SAR image was divided into four main stages which are de-noise, detection, cluster-discrimination and segment-recognition, respectively. The first three stages are used for searching region of interest (ROI). Once the ROIs are extracted, the recognition stage will be taken to compute the similarity between the ROIs and the templates in the electromagnetic simulation software National Electromagnetic Scattering Code (NESC). Due to the lack of the SAR raw data, the electromagnetic simulated images are added to the measured SAR background to simulate the battlefield environment8. The purpose of the system is to find the ROIs which can be the artificial military targets such as tanks, armored cars and so on and to categorize the ROIs into the right classes according to the existing templates. From the results we can see that the proposed system achieves a satisfactory result.

  19. Ultra-Wideband UHF Microstrip Array for GeoSAR Application

    NASA Technical Reports Server (NTRS)

    Thomas, Robert F.; Huang, John

    1998-01-01

    GeoSAR is a program sponsored by DARPA (Defense Advanced Research Projects Agency) and NASA (National Aeronautics and Space Administration) to develop an airborne, radar- based, commercial terrain mapping system for identification of geologic, seismic, and environmental information, it has two (dual-band at X and UHF) state-of-the-art interferometric synthetic aperture radar (SAR) ground mapping systems. The UHF interferometric system is utilized to penetrate the vegetation canopy and obtain true ground surface height information, while the Xband system will provide capability of mapping the top foliage surface. This paper presents the UHF antenna system where the required center frequency is 350 MHz with a 160 MHz of bandwidth (46% from 270 MHz to 430 MHz). The antenna is required to have dual-linear polarization with a peak gain of 10 dB at the center frequency and a minimum gain of 8 dB toward two ends of the frequency band. One of the most challenging tasks, in addition to achieving the 46% bandwidth, is to develop an antenna with small enough size to fit in the wing-tip pod of a Gulfstream II aircraft.

  20. NASA's DC-8 flying laboratory seen at sunset after a flight supporting the AirSAR 2004 Mesoamerica campaign

    NASA Image and Video Library

    2004-03-06

    NASA's DC-8 flying laboratory seen at sunset after a flight supporting the AirSAR 2004 Mesoamerica campaign. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that uses an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. The radar, developed by NASA's Jet Propulsion Laboratory, can penetrate clouds and also collect data at night. Its high-resolution sensors operate at multiple wavelengths and modes, allowing AirSAR to see beneath treetops, through thin sand, and dry snow pack. AirSAR's 2004 campaign is a collaboration of many U.S. and Central American institutions and scientists, including NASA; the National Science Foundation; the Smithsonian Institution; National Geographic; Conservation International; the Organization of Tropical Studies; the Central American Commission for Environment and Development; and the Inter-American Development Bank.

  1. NASA Dryden Mission Manager Walter Klein poses with school children that visited the airport during AirSAR 2004

    NASA Image and Video Library

    2004-03-08

    NASA Dryden Mission Manager Walter Klein poses with school children that visited the airport during AirSAR 2004. In spanish, he explained to them the mission of the DC-8 AirSAR 2004 Mesoamerican campaign in Costa Rica. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that uses an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. The radar, developed by NASA's Jet Propulsion Laboratory, can penetrate clouds and also collect data at night. Its high-resolution sensors operate at multiple wavelengths and modes, allowing AirSAR to see beneath treetops, through thin sand, and dry snow pack. AirSAR's 2004 campaign is a collaboration of many U.S. and Central American institutions and scientists, including NASA; the National Science Foundation; the Smithsonian Institution; National Geographic; Conservation International; the Organization of Tropical Studies; the Central American Commission for Environment and Development; and the Inter-American Development Bank.

  2. Glacier Grey in front of The Cuernos del Paine mountains, photographed from Lago Grey (Grey Lake) during NASA's AirSAR 2004 campaign in Chile

    NASA Image and Video Library

    2004-03-11

    Glacier Grey in front of the Cuernos del Paine mountains, photographed from Lago Grey (Grey Lake) during NASA's AirSAR 2004 campaign in Chile. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. Founded in 1959, Torres del Paine National Park encompasses 450,000 acres in the Patagonia region of Chile. This region is being studied by NASA using a DC-8 equipped with an Airborne Synthetic Aperture Radar (AirSAR) developed by scientists from NASA’s Jet Propulsion Laboratory. This is a very sensitive region that is important to scientists because the temperature has been consistently rising causing a subsequent melting of the region’s glaciers. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  3. Excretion and detection of SARS coronavirus and its nucleic acid from digestive system

    PubMed Central

    Wang, Xin-Wei; Li, Jin-Song; Guo, Ting-Kai; Zhen, Bei; Kong, Qing-Xin; Yi, Bin; Li, Zhong; Song, Nong; Jin, Min; Wu, Xiao-Ming; Xiao, Wen-Jun; Zhu, Xiu-Mei; Gu, Chang-Qing; Yin, Jing; Wei, Wei; Yao, Wei; Liu, Chao; Li, Jian-Feng; Ou, Guo-Rong; Wang, Min-Nian; Fang, Tong-Yu; Wang, Gui-Jie; Qiu, Yao-Hui; Wu, Huai-Huan; Chao, Fu-Huan; Li, Jun-Wen

    2005-01-01

    AIM: To study whether severe acute respiratory syndrome coronavirus (SARS-CoV) could be excreted from digestive system. METHODS: Cell culture and semi-nested RT-PCR were used to detect SARS-CoV and its RNA from 21 stool and urine samples, and a kind of electropositive filter media particles was used to concentrate the virus in 10 sewage samples from two hospitals receiving SARS patients in Beijing in China. RESULTS: It was demonstrated that there was no live SARS-CoV in all samples collected, but the RNA of SARS-CoV could be detected in seven stool samples from SARS patients with any one of the symptoms of fever, malaise, cough, or dyspnea, in 10 sewage samples before disinfection and 3 samples after disinfection from the two hospitals. The RNA could not be detected in urine and stool samples from patients recovered from SARS. CONCLUSION: Nucleic acid of SARS-CoV can be excreted through the stool of patients into sewage system, and the possibility of SARS-CoV transmitting through digestive system cannot be excluded. PMID:16038039

  4. Plans for the development of EOS SAR systems using the Alaska SAR facility. [Earth Observing System (EOS)

    NASA Technical Reports Server (NTRS)

    Carsey, F. D.; Weeks, W.

    1988-01-01

    The Alaska SAR Facility (ASF) program for the acquisition and processing of data from the ESA ERS-1, the NASDA ERS-1, and Radarsat and to carry out a program of science investigations using the data is introduced. Agreements for data acquisition and analysis are in place except for the agreement between NASA and Radarsat which is in negotiation. The ASF baseline system, consisting of the Receiving Ground System, the SAR Processor System and the Archive and Operations System, passed critical design review and is fully in implementation phase. Augments to the baseline system for systems to perform geophysical processing and for processing of J-ERS-1 optical data are in the design and implementation phase. The ASF provides a very effective vehicle with which to prepare for the Earth Observing System (EOS) in that it will aid the development of systems and technologies for handling the data volumes produced by the systems of the next decades, and it will also supply some of the data types that will be produced by EOS.

  5. Utility of Characterizing and Monitoring Suspected Underground Nuclear Sites with VideoSAR

    NASA Astrophysics Data System (ADS)

    Dauphin, S. M.; Yocky, D. A.; Riley, R.; Calloway, T. M.; Wahl, D. E.

    2016-12-01

    Sandia National Laboratories proposed using airborne synthetic aperture RADAR (SAR) collected in VideoSAR mode to characterize the Underground Nuclear Explosion Signature Experiment (UNESE) test bed site at the Nevada National Security Site (NNSS). The SNL SAR collected airborne, Ku-band (16.8 GHz center frequency), 0.2032 meter ground resolution over NNSS in August 2014 and X-band (9.6 GHz), 0.1016 meter ground resolution fully-polarimetric SAR in April 2015. This paper reports the findings of processing and exploiting VideoSAR for creating digital elevation maps, detecting cultural artifacts and exploiting full-circle polarimetric signatures. VideoSAR collects a continuous circle of phase history data, therefore, imagery can be formed over the 360-degrees of the site. Since the Ku-band VideoSAR had two antennas suitable for interferometric digital elevation mapping (DEM), DEMs could be generated over numerous aspect angles, filling in holes created by targets with height by imaging from all sides. Also, since the X-band VideoSAR was fully-polarimetric, scattering signatures could be gleaned from all angles also. Both of these collections can be used to find man-made objects and changes in elevation that might indicate testing activities. VideoSAR provides a unique, coherent measure of ground objects allowing one to create accurate DEMS, locate man-made objects, and identify scattering signatures via polarimetric exploitation. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. The authors would like to thank the National Nuclear Security Administration, Defense Nuclear Nonproliferation Research and Development, for sponsoring this work. We would also like to thank the Underground Nuclear Explosion Signatures Experiment team, a multi

  6. Ka-Band Digital Beamforming and SweepSAR Demonstration for Ice and Solid Earth Topography

    NASA Technical Reports Server (NTRS)

    Sadowy, Gregory; Ghaemi, Hirad; Heavy, Brandon; Perkovic, Dragana; Quddus, Momin; Zawadzki, Mark; Moller, Delwyn

    2010-01-01

    GLISTIN is an instrument concept for a single-pass interferometric SAR operating at 35.6 GHz. To achieve large swath widths using practical levels of transmitter power, a digitally-beamformed planar waveguide array is used. This paper describes results from a ground-based demonstration of a 16-receiver prototype. Furthermore, SweepSAR is emerging as promising technique for achieving very wide swaths for surface change detection. NASA and DLR are studying this approach for the DESDynI and Tandem-L missions. SweepSAR employs a reflector with a digitally-beamformed array feed. We will describe development of an airborne demonstration of SweepSAR using the GLISTIN receiver array and a reflector.

  7. Urban Modelling Performance of Next Generation SAR Missions

    NASA Astrophysics Data System (ADS)

    Sefercik, U. G.; Yastikli, N.; Atalay, C.

    2017-09-01

    In synthetic aperture radar (SAR) technology, urban mapping and modelling have become possible with revolutionary missions TerraSAR-X (TSX) and Cosmo-SkyMed (CSK) since 2007. These satellites offer 1m spatial resolution in high-resolution spotlight imaging mode and capable for high quality digital surface model (DSM) acquisition for urban areas utilizing interferometric SAR (InSAR) technology. With the advantage of independent generation from seasonal weather conditions, TSX and CSK DSMs are much in demand by scientific users. The performance of SAR DSMs is influenced by the distortions such as layover, foreshortening, shadow and double-bounce depend up on imaging geometry. In this study, the potential of DSMs derived from convenient 1m high-resolution spotlight (HS) InSAR pairs of CSK and TSX is validated by model-to-model absolute and relative accuracy estimations in an urban area. For the verification, an airborne laser scanning (ALS) DSM of the study area was used as the reference model. Results demonstrated that TSX and CSK urban DSMs are compatible in open, built-up and forest land forms with the absolute accuracy of 8-10 m. The relative accuracies based on the coherence of neighbouring pixels are superior to absolute accuracies both for CSK and TSX.

  8. Role of mechanical ventilation in the airborne transmission of infectious agents in buildings.

    PubMed

    Luongo, J C; Fennelly, K P; Keen, J A; Zhai, Z J; Jones, B W; Miller, S L

    2016-10-01

    Infectious disease outbreaks and epidemics such as those due to SARS, influenza, measles, tuberculosis, and Middle East respiratory syndrome coronavirus have raised concern about the airborne transmission of pathogens in indoor environments. Significant gaps in knowledge still exist regarding the role of mechanical ventilation in airborne pathogen transmission. This review, prepared by a multidisciplinary group of researchers, focuses on summarizing the strengths and limitations of epidemiologic studies that specifically addressed the association of at least one heating, ventilating and/or air-conditioning (HVAC) system-related parameter with airborne disease transmission in buildings. The purpose of this literature review was to assess the quality and quantity of available data and to identify research needs. This review suggests that there is a need for well-designed observational and intervention studies in buildings with better HVAC system characterization and measurements of both airborne exposures and disease outcomes. Studies should also be designed so that they may be used in future quantitative meta-analyses. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. X-SAR: The X-band synthetic aperture radar on board the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Werner, Marian U.

    1993-01-01

    The X-band synthetic aperture radar (X-SAR) is the German/Italian contribution to the NASA/JPL Shuttle Radar Lab missions as part of the preparation for the Earth Observation System (EOS) program. The Shuttle Radar Lab is a combination of several radars: an L-band (1.2 GHz) and a C-band (5.3 GHz) multipolarization SAR known as SIR-C (Shuttle Imaging Radar); and an X-band (9.6 GHz) vertically polarized SAR which will be operated synchronously over the same target areas to deliver calibrated multifrequency and multipolarization SAR data at multiple incidence angles from space. A joint German/Italian project office at DARA (German Space Agency) is responsible for the management of the X-SAR project. The space hardware has been developed and manufactured under industrial contract by Dornier and Alenia Spazio. Besides supporting all the technical and scientific tasks, DLR, in cooperation with ASI (Agencia Spaziale Italiano) is responsible for mission operation, calibration, and high precision SAR processing. In addition, DLR developed an airborne X-band SAR to support the experimenters with campaigns to prepare for the missions. The main advantage of adding a shorter wavelength (3 cm) radar to the SIR-C radars is the X-band radar's weaker penetration into vegetation and soil and its high sensitivity to surface roughness and associated phenomena. The performance of each of the three radars is comparable with respect to radiometric and geometric resolution.

  10. Initial observations on using SAR to monitor wildfire scars in boreal forests

    NASA Technical Reports Server (NTRS)

    Kasischke, E. S.; Bourgeau-Chavez, L. L.; French, N. H. F.; Harrell, P.; Christensen, N. L., Jr.

    1992-01-01

    Initial observations on the effects of wildfires in black spruce forests on radar backscatter are presented. Airborne and spaceborne SAR imagery are utilized to illustrate two distinct fire signatures. A theory is presented to explain these differences.

  11. Collaboration During the NASA ABoVE Airborne SAR Campaign: Sampling Strategies Used by NGEE Arctic and Other Partners in Alaska and Western Canada

    NASA Astrophysics Data System (ADS)

    Wullschleger, S. D.; Charsley-Groffman, L.; Baltzer, J. L.; Berg, A. A.; Griffith, P. C.; Jafarov, E. E.; Marsh, P.; Miller, C. E.; Schaefer, K. M.; Siqueira, P.; Wilson, C. J.; Kasischke, E. S.

    2017-12-01

    There is considerable interest in using L- and P-band Synthetic Aperture Radar (SAR) data to monitor variations in aboveground woody biomass, soil moisture, and permafrost conditions in high-latitude ecosystems. Such information is useful for quantifying spatial heterogeneity in surface and subsurface properties, and for model development and evaluation. To conduct these studies, it is desirable that field studies share a common sampling strategy so that the data from multiple sites can be combined and used to analyze variations in conditions across different landscape geomorphologies and vegetation types. In 2015, NASA launched the decade-long Arctic-Boreal Vulnerability Experiment (ABoVE) to study the sensitivity and resilience of these ecosystems to disturbance and environmental change. NASA is able to leverage its remote sensing strengths to collect airborne and satellite observations to capture important ecosystem properties and dynamics across large spatial scales. A critical component of this effort includes collection of ground-based data that can be used to analyze, calibrate and validate remote sensing products. ABoVE researchers at a large number of sites located in important Arctic and boreal ecosystems in Alaska and western Canada are following common design protocols and strategies for measuring soil moisture, thaw depth, biomass, and wetland inundation. Here we elaborate on those sampling strategies as used in the 2017 summer SAR campaign and address the sampling design and measurement protocols for supporting the ABoVE aerial activities. Plot size, transect length, and distribution of replicates across the landscape systematically allowed investigators to optimally sample a site for soil moisture, thaw depth, and organic layer thickness. Specific examples and data sets are described for the Department of Energy's Next-Generation Ecosystem Experiments (NGEE Arctic) project field sites near Nome and Barrow, Alaska. Future airborne and satellite

  12. The Larsen Ice Shelf in Antarctica viewed from NASA's DC-8 aircraft during the AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-16

    The Larsen Ice Shelf in Antarctica viewed from NASA's DC-8 aircraft during the AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. These photos are from the DC-8 aircraft while flying an AirSAR mission over Antarctica. The Antarctic Peninsula is more similar to Alaska and Patagonia than to the rest of the Antarctic continent. It is drained by fast glaciers, receives abundant precipitation, and melts significantly in the summer months. In recent decades, the Peninsula has experienced significant atmospheric warming (about 2 degrees C since 1950), which has triggered a vast and spectacular retreat of its floating ice shelves, glacier reduction, a decrease in permanent snow cover and a lengthening of the melt season. As a result, the contribution to sea level from this region could be rapid and substantial. With an area of 120,000 km, or ten times the Patagonia ice fields, the Peninsula could contribute as much as 0.4mm/yr sea level rise, which would be the largest single contribution to sea level from anywhere in the world. This region is being studied by NASA using a DC-8 equipped with an Airborne Synthetic Aperture Radar (AirSAR) developed by scientists from NASA’s Jet Propulsion Laboratory. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  13. 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

  14. Emergency product generation for disaster management using RISAT and DMSAR quick look SAR processors

    NASA Astrophysics Data System (ADS)

    Desai, Nilesh; Sharma, Ritesh; Kumar, Saravana; Misra, Tapan; Gujraty, Virendra; Rana, SurinderSingh

    2006-12-01

    Since last few years, ISRO has embarked upon the development of two complex Synthetic Aperture Radar (SAR) missions, viz. Spaceborne Radar Imaging Satellite (RISAT) and Airborne SAR for Disaster Mangement (DMSAR), as a capacity building measure under country's Disaster Management Support (DMS) Program, for estimating the extent of damage over large areas (~75 Km) and also assess the effectiveness of the relief measures undertaken during natural disasters such as cyclones, epidemics, earthquakes, floods and landslides, forest fires, crop diseases etc. Synthetic Aperture Radar (SAR) has an unique role to play in mapping and monitoring of large areas affected by natural disasters especially floods, owing to its unique capability to see through clouds as well as all-weather imaging capability. The generation of SAR images with quick turn around time is very essential to meet the above DMS objectives. Thus the development of SAR Processors, for these two SAR systems poses considerable challenges and design efforts. Considering the growing user demand and inevitable necessity for a full-fledged high throughput processor, to process SAR data and generate image in real or near-real time, the design and development of a generic SAR Processor has been taken up and evolved, which will meet the SAR processing requirements for both Airborne and Spaceborne SAR systems. This hardware SAR processor is being built, to the extent possible, using only Commercial-Off-The-Shelf (COTS) DSP and other hardware plug-in modules on a Compact PCI (cPCI) platform. Thus, the major thrust has been on working out Multi-processor Digital Signal Processor (DSP) architecture and algorithm development and optimization rather than hardware design and fabrication. For DMSAR, this generic SAR Processor operates as a Quick Look SAR Processor (QLP) on-board the aircraft to produce real time full swath DMSAR images and as a ground based Near-Real Time high precision full swath Processor (NRTP). It will

  15. SAR Product Improvements and Enhancements - SARprises

    DTIC Science & Technology

    2013-09-30

    paper on current fields at Orkney, Scotland, was accepted for publication in IEEE - TGARS and is currently in press (available on IEEE Xplore as Early...Sea surface velocity vector retrieval using dual-beam interferometry: First demonstration, IEEE TGARS, 43, 2494- 2502, 2005. [2] Chapron, B., F...Bight by airborne along-track interferometric SAR, Proc. IGARSS 2002, 1822-1824, IEEE , 2002. [4] Bjerklie, D.M., S.L. Dingman, C.J. Vorosmarty, C.H

  16. View of Glacier Grey from Lago Grey (Grey Lake), with the Cuernos del Paine mountains in the background, seen during NASA's AirSAR 2004 campaign in Chile

    NASA Image and Video Library

    2004-03-11

    View of Glacier Grey from Lago Grey (Grey Lake), with the Cuernos del Paine mountains in the background, seen during NASA's AirSAR 2004 campaign in Chile. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. Founded in 1959, Torres del Paine National Park encompasses 450,000 acres in the Patagonia region of Chile. This region is being studied by NASA using a DC-8 equipped with an Airborne Synthetic Aperture Radar (AirSAR) developed by scientists from NASA’s Jet Propulsion Laboratory. This is a very sensitive region that is important to scientists because the temperature has been consistently rising causing a subsequent melting of the region’s glaciers. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  17. The Cuernos del Paine mountains in Torres del Paine National Park in Chile provide a backdrop to a herd of guanacos during NASA's AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-11

    The Cuernos del Paine mountains in Torres del Paine National Park in Chile provide a backdrop to a herd of guanacos during NASA's AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. Founded in 1959, Torres del Paine National Park encompasses 450,000 acres in the Patagonia region of Chile. This region is being studied by NASA using a DC-8 equipped with an Airborne Synthetic Aperture Radar (AirSAR) developed by scientists from NASA’s Jet Propulsion Laboratory. This is a very sensitive region that is important to scientists because the temperature has been consistently rising causing a subsequent melting of the region’s glaciers. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  18. Forest Structure Characterization Using JPL's UAVSAR Multi-Baseline Polarimetric SAR Interferometry and Tomography

    NASA Technical Reports Server (NTRS)

    Neumann, Maxim; Hensley, Scott; Lavalle, Marco; Ahmed, Razi

    2013-01-01

    This paper concerns forest remote sensing using JPL's multi-baseline polarimetric interferometric UAVSAR data. It presents exemplary results and analyzes the possibilities and limitations of using SAR Tomography and Polarimetric SAR Interferometry (PolInSAR) techniques for the estimation of forest structure. Performance and error indicators for the applicability and reliability of the used multi-baseline (MB) multi-temporal (MT) PolInSAR random volume over ground (RVoG) model are discussed. Experimental results are presented based on JPL's L-band repeat-pass polarimetric interferometric UAVSAR data over temperate and tropical forest biomes in the Harvard Forest, Massachusetts, and in the La Amistad Park, Panama and Costa Rica. The results are partially compared with ground field measurements and with air-borne LVIS lidar data.

  19. Forest Structure Characterization Using Jpl's UAVSAR Multi-Baseline Polarimetric SAR Interferometry and Tomography

    NASA Technical Reports Server (NTRS)

    Neumann, Maxim; Hensley, Scott; Lavalle, Marco; Ahmed, Razi

    2013-01-01

    This paper concerns forest remote sensing using JPL's multi-baseline polarimetric interferometric UAVSAR data. It presents exemplary results and analyzes the possibilities and limitations of using SAR Tomography and Polarimetric SAR Interferometry (PolInSAR) techniques for the estimation of forest structure. Performance and error indicators for the applicability and reliability of the used multi-baseline (MB) multi-temporal (MT) PolInSAR random volume over ground (RVoG) model are discussed. Experimental results are presented based on JPL's L-band repeat-pass polarimetric interferometric UAVSAR data over temperate and tropical forest biomes in the Harvard Forest, Massachusetts, and in the La Amistad Park, Panama and Costa Rica. The results are partially compared with ground field measurements and with air-borne LVIS lidar data.

  20. A first assessment of Sentinel-3 SAR altimetry over ice sheets

    NASA Astrophysics Data System (ADS)

    McMillan, M.; Muir, A. S.; Shepherd, A.

    2017-12-01

    The first Sentinel-3 satellite was launched in 2016 and carries onboard a Ku-band Synthetic Aperture Radar (SAR) altimeter. With coverage up to a latitude of 81.5 degrees and a repeat period of 27 days, it offers the opportunity to measure surface topography and elevation change across much of the Antarctic and Greenland Ice Sheets, therefore continuing the existing 25 year radar altimeter record. The global operation of Sentinel-3 in SAR mode differs from all past Ku-band instruments; for the first time SAR measurements are routinely acquired across the interiors of the ice sheets; however unlike CryoSat-2 it does not carry an interferometer to aid signal retrieval in regions of complex coastal terrain. In view of these differences and the novel characteristics of the Sentinel-3 system, assessments of the performance of the instrument are required, to evaluate the satellite's utility for monitoring Earth's Polar regions. Here, we analyse data acquired during the first year of routine operations, to assess the performance of the Sentinel-3 SAR altimeter to date. We focus both on inland ice sheet regions, where Sentinel-3 provides the first operational SAR altimeter measurements, and also on coastal areas with more complex topography. We investigate SAR waveforms and retrieved elevations in both regions, and through comparison to measurements from earlier missions examine the impact of the different modes of operation. We also conduct a high level evaluation of the data, by comparing it to reference airborne altimetry, to provide an assessment of Sentinel-3 performance to date over ice sheets.

  1. NASA Dryden Mission Manager Walter Klein poses with school children that visited the DC-8 during AirSAR 2004 in Punta Arenas, Chile

    NASA Image and Video Library

    2004-03-10

    NASA Dryden Mission Manager Walter Klein poses with school children that visited the DC-8 during AirSAR 2004 in Punta Arenas, Chile. AirSAR 2004 is a three-week expedition by an international team of scientists that uses an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central and South America with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. In South America and Antarctica, AirSAR collected imagery and data to help determine the contribution of Southern Hemisphere glaciers to sea level rise due to climate change. In Patagonia, researchers found this contribution had more than doubled from 1995 to 2000, compared to the previous 25 years. AirSAR data will make it possible to determine whether that trend is continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  2. A spider photographed during NASA's AirSAR 2004 Mesoamerica campaign in the La Selva region of the Costa Rican rain forest

    NASA Image and Video Library

    2004-03-04

    A spider photographed during NASA's AirSAR 2004 Mesoamerica campaign in the La Selva region of the Costa Rican rain forest. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that uses an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. The radar, developed by NASA's Jet Propulsion Laboratory, can penetrate clouds and also collect data at night. Its high-resolution sensors operate at multiple wavelengths and modes, allowing AirSAR to see beneath treetops, through thin sand, and dry snow pack. AirSAR's 2004 campaign is a collaboration of many U.S. and Central American institutions and scientists, including NASA; the National Science Foundation; the Smithsonian Institution; National Geographic; Conservation International; the Organization of Tropical Studies; the Central American Commission for Environment and Development; and the Inter-American Development Bank.

  3. Agile waveforms for joint SAR-GMTI processing

    NASA Astrophysics Data System (ADS)

    Jaroszewski, Steven; Corbeil, Allan; McMurray, Stephen; Majumder, Uttam; Bell, Mark R.; Corbeil, Jeffrey; Minardi, Michael

    2016-05-01

    Wideband radar waveforms that employ spread-spectrum techniques were investigated and experimentally tested. The waveforms combine bi-phase coding with a traditional LFM chirp and are applicable to joint SAR-GMTI processing. After de-spreading, the received signals can be processed to support simultaneous GMTI and high resolution SAR imaging missions by airborne radars. The spread spectrum coding techniques can provide nearly orthogonal waveforms and offer enhanced operations in some environments by distributing the transmitted energy over a large instantaneous bandwidth. The LFM component offers the desired Doppler tolerance. In this paper, the waveforms are formulated and a shift-register approach for de-spreading the received signals is described. Hardware loop-back testing has shown the feasibility of using these waveforms in experimental radar test bed.

  4. 76 FR 76333 - Notification for Airborne Wind Energy Systems (AWES)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-07

    ...-1279; Notice No. 11-07] Notification for Airborne Wind Energy Systems (AWES) AGENCY: Federal Aviation... CFR) part 77, ``Safe, Efficient Use and Preservation of the Navigable Airspace,'' to airborne wind energy systems (AWES). In addition, this notice requests information from airborne wind energy system...

  5. Pre-Columbian archaeological ruins are revealed through Costa Rican rain forest in this photo taken during NASA's AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-05

    Pre-Columbian archaeological ruins are revealed through Costa Rican rain forest in this photo taken during NASA's AirSAR 2004 Mesoamerica campaign. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that uses an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. The radar, developed by NASA's Jet Propulsion Laboratory, can penetrate clouds and also collect data at night. Its high-resolution sensors operate at multiple wavelengths and modes, allowing AirSAR to see beneath treetops, through thin sand, and dry snow pack. Much of the archaeological evidence needed to understand Pre-Columbian societies in Central America comes from features on the landscape. Difficult terrain and logistics have limited ground data collection. AirSAR helped to detect signs of ancient civilizations hidden beneath the forest. Its images will shed insights into the way modern humans interact with their landscape, and how ancient peoples lived and what became of their civilizations.

  6. NASA Administrator Sean O'Keefe making a presentation to Fernando Gutierrez during the AirSAR 2004 hangar naming ceremony

    NASA Image and Video Library

    2004-03-03

    NASA Administrator Sean O'Keefe making a presentation to Fernando Gutierrez, Costa Rican Minister of Science and Technology(MICIT), during the AirSAR 2004 Mesoamerica hangar naming ceremony. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  7. 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.

  8. The Larsen Ice Shelf in Antarctica viewed from NASA's DC-8 aircraft during the AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-16

    The Larsen Ice Shelf in Antarctica viewed from NASA's DC-8 aircraft during the AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. These photos are from the DC-8 aircraft while flying an AirSAR mission over Antarctica. The Antarctic Peninsula is more similar to Alaska and Patagonia than to the rest of the Antarctic continent. It is drained by fast glaciers, receives abundant precipitation, and melts significantly in the summer months. In recent decades, the Peninsula has experienced significant atmospheric warming (about 2 degrees C since 1950), which has triggered a vast and spectacular retreat of its floating ice shelves, glacier reduction, a decrease in permanent snow cover and a lengthening of the melt season. As a result, the contribution to sea level from this region could be rapid and substantial. With an area of 120,000 km, or ten times the Patagonia ice fields, the Peninsula could contribute as much as 0.4mm/yr sea level rise, which would be the largest single contribution to sea level from anywhere in the world. This region is being studied by NASA using a DC-8 equipped with the Airborne Synthetic Aperture Radar developed by scientists from NASA’s Jet Propulsion Laboratory. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  9. The Larsen Ice Shelf in Antarctica viewed from NASA's DC-8 aircraft during the AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-13

    The Larsen Ice Shelf in Antarctica viewed from NASA's DC-8 aircraft during the AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. These photos are from the DC-8 aircraft while flying an AirSAR mission over Antarctica. The Antarctic Peninsula is more similar to Alaska and Patagonia than to the rest of the Antarctic continent. It is drained by fast glaciers, receives abundant precipitation, and melts significantly in the summer months. In recent decades, the Peninsula has experienced significant atmospheric warming (about 2 degrees C since 1950), which has triggered a vast and spectacular retreat of its floating ice shelves, glacier reduction, a decrease in permanent snow cover and a lengthening of the melt season. As a result, the contribution to sea level from this region could be rapid and substantial. With an area of 120,000 km, or ten times the Patagonia ice fields, the Peninsula could contribute as much as 0.4mm/yr sea level rise, which would be the largest single contribution to sea level from anywhere in the world. This region is being studied by NASA using a DC-8 equipped with the Airborne Synthetic Aperture Radar developed by scientists from NASA’s Jet Propulsion Laboratory. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  10. UAV-based L-band SAR with precision flight path control

    NASA Astrophysics Data System (ADS)

    Madsen, Soren N.; Hensley, Scott; Wheeler, Kevin; Sadowy, Gregory A.; Miller, Tim; Muellerschoen, Ron; Lou, Yunling; Rosen, Paul A.

    2005-01-01

    NASA's Jet Propulsion Laboratory is currently implementing a reconfigurable polarimetric L-band synthetic aperture radar (SAR), specifically designed to acquire airborne repeat track interferometric (RTI) SAR data, also know as differential interferometric measurements. Differential interferometry can provide key displacement measurements, important for the scientific studies of Earthquakes and volcanoes1. 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 radar will be designed to operate on a UAV (Unmanned Arial Vehicle) but will initially be demonstrated on a minimally piloted vehicle (MPV), such as the Proteus build by Scaled Composites. The application requires control of the flight path to within a 10 m tube to support repeat track and formation flying measurements. The design is fully polarimetric with an 80 MHz bandwidth (2 m range resolution) and 16 km range swath. The antenna is an electronically steered array to assure that the actual antenna pointing can be controlled independent of the wind direction and speed. The system will nominally operate at 45,000 ft. The program started out as a Instrument Incubator Project (IIP) funded by NASA Earth Science and Technology Office (ESTO).

  11. UAV-Based L-Band SAR with Precision Flight Path Control

    NASA Technical Reports Server (NTRS)

    Madsen, Soren N.; Hensley, Scott; Wheeler, Kevin; Sadowy, Greg; Miller, Tim; Muellerschoen, Ron; Lou, Yunling; Rosen, Paul

    2004-01-01

    NASA's Jet Propulsion Laboratory is currently implementing a reconfigurable polarimetric L-band synthetic aperture radar (SAR), specifically designed to acquire airborne repeat track interferometric (RTI) SAR data, also know as differential interferometric measurements. Differential interferometry can provide key displacement measurements, important for the scientific studies of Earthquakes and volcanoes. 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 radar will be designed to operate on a UAV (Unmanned Arial Vehicle) but will initially be demonstrated on a minimally piloted vehicle (MPV), such as the Proteus build by Scaled Composites. The application requires control of the flight path to within a 10 meter tube to support repeat track and formation flying measurements. The design is fully polarimetric with an 80 MHz bandwidth (2 meter range resolution) and 16 kilometer range swath. The antenna is an electronically steered array to assure that the actual antenna pointing can be controlled independent of the wind direction and speed. The system will nominally operate at 45,000 ft. The program started out as a Instrument Incubator Project (IIP) funded by NASA Earth Science and Technology Office (ESTO).

  12. 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.

  13. Integration of SAR and AIS for ship detection and identification

    NASA Astrophysics Data System (ADS)

    Yang, Chan-Su; Kim, Tae-Ho

    2012-06-01

    This abstract describes the preliminary design concept for an integration system of SAR and AIS data. 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 also obtained on the same date as of the SAR acquisition for the purpose to perform integration test. Once both data reports are obtained, one need to match the timings of AIS data acquisition over the SAR image acquisition time with consideration of local time & boundary to extract the closest time signal from AIS report in order to know the AIS based ship positions, but still one cannot be able to distinguish which ships have the AIS transponder after projection of AIS based position onto the SAR image acquisition boundary. As far as integration is concerned, the ship dead-reckoning concept is most important forecasted position which provides the AIS based ship position at the time of SAR image acquisition and also provides the hints for azimuth shift which occurred in SAR image for the case of moving ships which moves in the direction perpendicular to the direction of flight path. Unknown ship's DR estimation is to be carried out based on the initial positions, speed and course over ground, which has already been shorted out from AIS reports, during the step of time matching. This DR based ship's position will be the candidate element for searching the SAR based ship targets for the purpose of identification & matching within the certain boundary around DR. The searching method is performed by means of estimation of minimum distance from ship's DR to SAR based ship position, and once it determines, so the candidate element will look for matching like ship size match of DR based ship's dimension wrt SAR based ship's edge, there may be some error during the matching with SAR based ship edges with actual ship's hull design as per the longitudinal and transverse axis size information obtained from the AIS reports due to

  14. NASA Dryden's DC-8 on the ramp at Jaun Santamaria International Airport, San Jose, Costa Rica during the AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-03

    NASA Dryden's DC-8 on the ramp at Jaun Santamaria International Airport, San Jose, Costa Rica during the AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  15. NASA Dryden's DC-8 on the ramp at Jaun Santamaria International Airport, San Jose, Costa Rica, during the AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-03

    NASA Dryden's DC-8 on the ramp at Jaun Santamaria International Airport, San Jose, Costa Rica during the AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  16. NASA Dryden DC-8 maintenance crew members inspect the aircraft prior to take-off for an AirSAR 2004 flight

    NASA Image and Video Library

    2004-03-06

    NASA Dryden DC-8 maintenance crew members inspect the aircraft prior to take-off. L-R; Scott Silver, Paul Ristrim and Mike Lakowski. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that uses an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. The radar, developed by NASA's Jet Propulsion Laboratory, can penetrate clouds and also collect data at night. Its high-resolution sensors operate at multiple wavelengths and modes, allowing AirSAR to see beneath treetops, through thin sand, and dry snow pack. AirSAR's 2004 campaign is a collaboration of many U.S. and Central American institutions and scientists, including NASA; the National Science Foundation; the Smithsonian Institution; National Geographic; Conservation International; the Organization of Tropical Studies; the Central American Commission for Environment and Development; and the Inter-American Development Bank.

  17. Source model for the Copahue volcano magma plumbing system constrained by InSAR surface deformation observations

    NASA Astrophysics Data System (ADS)

    Lundgren, Paul; Nikkhoo, Mehdi; Samsonov, Sergey V.; Milillo, Pietro; Gil-Cruz, Fernando; Lazo, Jonathan

    2017-07-01

    Copahue volcano straddling the edge of the Agrio-Caviahue caldera along the Chile-Argentina border in the southern Andes has been in unrest since inflation began in late 2011. We constrain Copahue's source models with satellite and airborne interferometric synthetic aperture radar (InSAR) deformation observations. InSAR time series from descending track RADARSAT-2 and COSMO-SkyMed data span the entire inflation period from 2011 to 2016, with their initially high rates of 12 and 15 cm/yr, respectively, slowing only slightly despite ongoing small eruptions through 2016. InSAR ascending and descending track time series for the 2013-2016 time period constrain a two-source compound dislocation model, with a rate of volume increase of 13 × 106 m3/yr. They consist of a shallow, near-vertical, elongated source centered at 2.5 km beneath the summit and a deeper, shallowly plunging source centered at 7 km depth connecting the shallow source to the deeper caldera. The deeper source is located directly beneath the volcano tectonic seismicity with the lower bounds of the seismicity parallel to the plunge of the deep source. InSAR time series also show normal fault offsets on the NE flank Copahue faults. Coulomb stress change calculations for right-lateral strike slip (RLSS), thrust, and normal receiver faults show positive values in the north caldera for both RLSS and normal faults, suggesting that northward trending seismicity and Copahue fault motion within the caldera are caused by the modeled sources. Together, the InSAR-constrained source model and the seismicity suggest a deep conduit or transfer zone where magma moves from the central caldera to Copahue's upper edifice.

  18. VIP’s onboard NASA's DC-8 aircraft during the AirSAR 2004 Mesoamerica campaign

    NASA Image and Video Library

    2004-03-03

    VIP’s onboard NASA's DC-8 aircraft during the AirSAR 2004 Mesoamerica campaign, L-R: Mr. John Danilovich, US Ambassador to Costa Rica; Dr. Gahssem Asrar, NASA Associate Administrator for Earth Science Enterprises; Dr. Sonia Marta Mora, President of the Costa Rican National Rector’s Council; and Fernando Gutierrez, Costa Rican Minister of Science and Technology(MICIT). AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  19. NASA's DC-8 flying laboratory takes off from Juan Santamaria International Airport in San Jose, Costa Rica, on NASA's AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-06

    NASA's DC-8 flying laboratory takes off from Juan Santamaria International Airport in San Jose, Costa Rica, on NASA's AirSAR 2004 campaign. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that uses an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. The radar, developed by NASA's Jet Propulsion Laboratory, can penetrate clouds and also collect data at night. Its high-resolution sensors operate at multiple wavelengths and modes, allowing AirSAR to see beneath treetops, through thin sand, and dry snow pack. AirSAR's 2004 campaign is a collaboration of many U.S. and Central American institutions and scientists, including NASA; the National Science Foundation; the Smithsonian Institution; National Geographic; Conservation International; the Organization of Tropical Studies; the Central American Commission for Environment and Development; and the Inter-American Development Bank.

  20. This photograph shows a stream in the La Selva region of the Costa Rican rain forest, taken during NASA's AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-05

    This photograph shows a stream in the La Selva region of the Costa Rican rain forest, taken during NASA's AirSAR 2004 campaign. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that uses an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. The radar, developed by NASA's Jet Propulsion Laboratory, can penetrate clouds and also collect data at night. Its high-resolution sensors operate at multiple wavelengths and modes, allowing AirSAR to see beneath treetops, through thin sand, and dry snow pack. AirSAR's 2004 campaign is a collaboration of many U.S. and Central American institutions and scientists, including NASA; the National Science Foundation; the Smithsonian Institution; National Geographic; Conservation International; the Organization of Tropical Studies; the Central American Commission for Environment and Development; and the Inter-American Development Bank.

  1. 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.

  2. 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.

  3. Utilizing feedback in adaptive SAR ATR systems

    NASA Astrophysics Data System (ADS)

    Horsfield, Owen; Blacknell, David

    2009-05-01

    Existing SAR ATR systems are usually trained off-line with samples of target imagery or CAD models, prior to conducting a mission. If the training data is not representative of mission conditions, then poor performance may result. In addition, it is difficult to acquire suitable training data for the many target types of interest. The Adaptive SAR ATR Problem Set (AdaptSAPS) program provides a MATLAB framework and image database for developing systems that adapt to mission conditions, meaning less reliance on accurate training data. A key function of an adaptive system is the ability to utilise truth feedback to improve performance, and it is this feature which AdaptSAPS is intended to exploit. This paper presents a new method for SAR ATR that does not use training data, based on supervised learning. This is achieved by using feature-based classification, and several new shadow features have been developed for this purpose. These features allow discrimination of vehicles from clutter, and classification of vehicles into two classes: targets, comprising military combat types, and non-targets, comprising bulldozers and trucks. The performance of the system is assessed using three baseline missions provided with AdaptSAPS, as well as three additional missions. All performance metrics indicate a distinct learning trend over the course of a mission, with most third and fourth quartile performance levels exceeding 85% correct classification. It has been demonstrated that these performance levels can be maintained even when truth feedback rates are reduced by up to 55% over the course of a mission.

  4. Estimation of Boreal Forest Biomass Using Spaceborne SAR Systems

    NASA Technical Reports Server (NTRS)

    Saatchi, Sassan; Moghaddam, Mahta

    1995-01-01

    In this paper, we report on the use of a semiempirical algorithm derived from a two layer radar backscatter model for forest canopies. The model stratifies the forest canopy into crown and stem layers, separates the structural and biometric attributes of the canopy. The structural parameters are estimated by training the model with polarimetric SAR (synthetic aperture radar) data acquired over homogeneous stands with known above ground biomass. Given the structural parameters, the semi-empirical algorithm has four remaining parameters, crown biomass, stem biomass, surface soil moisture, and surface rms height that can be estimated by at least four independent SAR measurements. The algorithm has been used to generate biomass maps over the entire images acquired by JPL AIRSAR and SIR-C SAR systems. The semi-empirical algorithms are then modified to be used by single frequency radar systems such as ERS-1, JERS-1, and Radarsat. The accuracy. of biomass estimation from single channel radars is compared with the case when the channels are used together in synergism or in a polarimetric system.

  5. L to R; Walter Klein (in tan flight suit), Tim Miller, and David Bushman briefing press in Santiago, Chile, for NASA's AirSAR 2004 mission

    NASA Image and Video Library

    2004-03-10

    L to R; NASA Dryden Mission Manager Walter Klein (in tan flight suit), JPL AirSAR Scientist Tim Miller, and Mission Manager David Bushman briefing press in Santiago, Chile, for NASA's AirSAR 2004 mission. AirSAR 2004 is a three-week expedition by an international team of scientists that uses an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central and South America with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. In South America and Antarctica, AirSAR collected imagery and data to help determine the contribution of Southern Hemisphere glaciers to sea level rise due to climate change. In Patagonia, researchers found this contribution had more than doubled from 1995 to 2000, compared to the previous 25 years. AirSAR data will make it possible to determine whether that trend is continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  6. An integrated compact airborne multispectral imaging system using embedded computer

    NASA Astrophysics Data System (ADS)

    Zhang, Yuedong; Wang, Li; Zhang, Xuguo

    2015-08-01

    An integrated compact airborne multispectral imaging system using embedded computer based control system was developed for small aircraft multispectral imaging application. The multispectral imaging system integrates CMOS camera, filter wheel with eight filters, two-axis stabilized platform, miniature POS (position and orientation system) and embedded computer. The embedded computer has excellent universality and expansibility, and has advantages in volume and weight for airborne platform, so it can meet the requirements of control system of the integrated airborne multispectral imaging system. The embedded computer controls the camera parameters setting, filter wheel and stabilized platform working, image and POS data acquisition, and stores the image and data. The airborne multispectral imaging system can connect peripheral device use the ports of the embedded computer, so the system operation and the stored image data management are easy. This airborne multispectral imaging system has advantages of small volume, multi-function, and good expansibility. The imaging experiment results show that this system has potential for multispectral remote sensing in applications such as resource investigation and environmental monitoring.

  7. AirSAR 2004 plaque unveiling by NASA Administrator Sean O'Keefe and Fernando Gutierrez, Costa Rican Minister of Science and Technology(MICIT)

    NASA Image and Video Library

    2004-03-03

    AirSAR 2004 Mesoamerica plaque unveiling by NASA Administrator Sean O'Keefe and Fernando Gutierrez, Costa Rican Minister of Science and Technology(MICIT). AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  8. MAX-91: Polarimetric SAR results on Montespertoli site

    NASA Technical Reports Server (NTRS)

    Baronti, S.; Luciani, S.; Moretti, S.; Paloscia, S.; Schiavon, G.; Sigismondi, S.

    1993-01-01

    The polarimetric Synthetic Aperture Radar (SAR) is a powerful sensor for high resolution ocean and land mapping and particularly for monitoring hydrological parameters in large watersheds. There is currently much research in progress to assess the SAR operational capability as well as to estimate the accuracy achievable in the measurements of geophysical parameters with the presently available airborne and spaceborne sensors. An important goal of this research is to improve our understanding of the basic mechanisms that control the interaction of electro-magnetic waves with soil and vegetation. This can be done both by developing electromagnetic models and by analyzing statistical relations between backscattering and ground truth data. A systematic investigation, which aims at a better understanding of the information obtainable from the multi-frequency polarimetric SAR to be used in agro-hydrology, is in progress by our groups within the framework of SIR-C/X-SAR Project and has achieved a most significant milestone with the NASA/JPL Aircraft Campaign named MAC-91. Indeed this experiment allowed us to collect a large and meaningful data set including multi-temporal multi-frequency polarimetric SAR measurements and ground truth. This paper presents some significant results obtained over an agricultural flat area within the Montespertoli site, where intensive ground measurements were carried out. The results are critically discussed with special regard to the information associated with polarimetric data.

  9. Azimuthal resolution degradation due to ocean surface motion in focused arrays and SARS

    NASA Astrophysics Data System (ADS)

    1990-06-01

    During the meeting at WHOI (5-18-90), a discussion arose of the ability of the focused array to simulate the R/v ratios typical of airborne and/or spaceborne SARs. In particular, the ability was questioned of the focused array to yield the same azimuthal resolution, rho, as the SAR. Although the focused array can be sampled to yield the same azimuthal resolution as the SAR, it is likely that the images generated by the focused array will not be identical to those produced by a SAR with the same azimuth resolution. For a true SAR, biases in the Doppler history of azimuthally traveling waves due to their along-track motion will cause shifts in their apparent position. This will cause waves which are physically at one location to shift over several pixel widths in the image. The limited swath width of the focused array will prevent if from observing scattered power from waves falling outside the swath, thus such waves will not affect the image formed within the swath, as would happen in the SAR. Thus, it is likely that the focused array will not yield the same image as a SAR having the same resolution.

  10. Low cost realization of space-borne synthectic aperture radar - MicroSAR

    NASA Astrophysics Data System (ADS)

    Carter, D.; Hall, C.

    Spaceborne Earth Observation data has been used for decades in the areas of meteorology and optical imaging. The systems and satellites have, in the main, been owned and operated by a few government institutions and agencies. More recently industrial organizations in North America have joined the list. Few of these, however, include Synthetic Aperture Radar (SAR)., although the additional utility in terms of all weather, 24 hour measurement capability over the Earth's surface is well recognized. Three major factors explain this:1) Relationships between the SAR measurements of radar backscatter and images to the specific information needs have not been seen as sufficiently well understood or robust2) Availability of suitable sources, at the relevant performance and data quality have been inadequate to provide service assurance that is necessary to sustain commercial businesses3) Costs associated with building, launching and operating spaceborne SAR have not been low enough as to achieve an acceptable return of investment. A significant amount of research and development has been undertaken throughout the World to establish reliable and robust algorithms for information extraction from SAR data. Much of this work has been carried out utilizing airborne systems over localized and carefully controlled regions. In addition, an increasing number of pilot services have been offered by geo-information providers. This has allowed customer confidence to grow. With the status of spaceborne SAR being effectively in the development phase, commercial funding has been scarce, and there has been need to rely on government and institutional budgets. Today the increasing maturity of the technology of SAR and its applications is beginning to attract the commercial sector. This is the funding necessary to realize sufficient assets to be able to provide a robust supply of SAR data to the geo-information providers and subsequently a reliable service to customers. Reducing the costs

  11. SAR image dataset of military ground targets with multiple poses for ATR

    NASA Astrophysics Data System (ADS)

    Belloni, Carole; Balleri, Alessio; Aouf, Nabil; Merlet, Thomas; Le Caillec, Jean-Marc

    2017-10-01

    Automatic Target Recognition (ATR) is the task of automatically detecting and classifying targets. Recognition using Synthetic Aperture Radar (SAR) images is interesting because SAR images can be acquired at night and under any weather conditions, whereas optical sensors operating in the visible band do not have this capability. Existing SAR ATR algorithms have mostly been evaluated using the MSTAR dataset.1 The problem with the MSTAR is that some of the proposed ATR methods have shown good classification performance even when targets were hidden,2 suggesting the presence of a bias in the dataset. Evaluations of SAR ATR techniques are currently challenging due to the lack of publicly available data in the SAR domain. In this paper, we present a high resolution SAR dataset consisting of images of a set of ground military target models taken at various aspect angles, The dataset can be used for a fair evaluation and comparison of SAR ATR algorithms. We applied the Inverse Synthetic Aperture Radar (ISAR) technique to echoes from targets rotating on a turntable and illuminated with a stepped frequency waveform. The targets in the database consist of four variants of two 1.7m-long models of T-64 and T-72 tanks. The gun, the turret position and the depression angle are varied to form 26 different sequences of images. The emitted signal spanned the frequency range from 13 GHz to 18 GHz to achieve a bandwidth of 5 GHz sampled with 4001 frequency points. The resolution obtained with respect to the size of the model targets is comparable to typical values obtained using SAR airborne systems. Single polarized images (Horizontal-Horizontal) are generated using the backprojection algorithm.3 A total of 1480 images are produced using a 20° integration angle. The images in the dataset are organized in a suggested training and testing set to facilitate a standard evaluation of SAR ATR algorithms.

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

    NASA Technical Reports Server (NTRS)

    Webster, Chris; Freudinger, 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.

  13. NASA's DC-8 flying laboratory takes off from Juan Santamaria International Airport in San Jose, Costa Rica, on NASA's AirSAR 2004 campaign

    NASA Image and Video Library

    2004-03-03

    NASA's DC-8 flying laboratory takes off from Juan Santamaria International Airport in San Jose, Costa Rica, on NASA's AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  14. Mr. John Danilovich, US Ambassador to Costa Rica, and NASA Administrator Sean O'Keefe at the AirSAR 2004 Mesoamerica hangar naming ceremony

    NASA Image and Video Library

    2004-03-03

    Mr. John Danilovich, US Ambassador to Costa Rica, and NASA Administrator Sean O'Keefe at the AirSAR 2004 Mesoamerica hangar naming ceremony. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  15. A Constellation of CubeSat InSAR Sensors for Rapid-Revisit Surface Deformation Studies

    NASA Astrophysics Data System (ADS)

    Wye, L.; Lee, S.; Yun, S. H.; Zebker, H. A.; Stock, J. D.; Wicks, C. W., Jr.; Doe, R.

    2016-12-01

    The 2007 NRC Decadal Survey for Earth Sciences highlights three major Earth surface deformation themes: 1) solid-earth hazards and dynamics; 2) human health and security; and 3) land-use change, ecosystem dynamics and biodiversity. Space-based interferometric synthetic aperture radar (InSAR) is a key change detection tool for addressing these themes. Here, we describe the mission and radar payload design for a constellation of S-band InSAR sensors specifically designed to provide the global, high temporal resolution, sub-cm level deformation accuracy needed to address some of the major Earth system goals. InSAR observations with high temporal resolution are needed to properly monitor certain nonlinearly time-varying features (e.g., unstable volcanoes, active fault lines, and heavily-used groundwater or hydrocarbon reservoirs). Good temporal coverage is also needed to reduce atmospheric artifacts by allowing multiple acquisitions to be averaged together, since each individual SAR measurement is corrupted by up to several cm of atmospheric noise. A single InSAR platform is limited in how often it can observe a given scene without sacrificing global spatial coverage. Multiple InSAR platforms provide the spatial-temporal flexibility required to maximize the science return. However, building and launching multiple InSAR platforms is cost-prohibitive for traditional satellites. SRI International (SRI) and our collaborators are working to exploit developments in nanosatellite technology, in particular the emergence of the CubeSat standard, to provide high-cadence InSAR capabilities in an affordable package. The CubeSat Imaging Radar for Earth Science (CIRES) subsystem, a prototype SAR elec­tronics package developed by SRI with support from a 2014 NASA ESTO ACT award, is specifically scaled to be a drop-in radar solution for resource-limited delivery systems like CubeSats and small airborne vehicles. Here, we present our mission concept and flow-down requirements for a

  16. Large-scale time-series InSAR analysis of the Sacramento-San Joaquin delta subsidence using UAVSAR

    NASA Astrophysics Data System (ADS)

    Bekaert, D. P.; Jones, C. E.; An, K.; Huang, M. H.

    2016-12-01

    The Sacramento-San Joaquin delta (Delta) contains more than 1700 km of levees that protect various reclaimed lands from flooding. Most of the delta is experiencing subsidence at rates that can exceed 5 cm/yr locally, and which can affect the structural integrity of the levees. In-situ and airborne LIDAR monitoring of this extensive levee network is expensive, making Interferometric Synthetic Aperture Radar (InSAR) an attractive, cost-effective alternative that can provide uniform and consistent monitoring. InSAR has proven to be a powerful technique to study surface displacements at high accuracy (few mm/year), over large regions (up to 250 km wide swaths), and at a high spatial resolution (up to a meter). However widespread usage of InSAR, particularly within the application community, is challenged by several technical issues, the most significant of which are decorrelation noise introduced by a change of scattering properties (e.g., moisture and vegetation), and noise due to variation in atmospheric properties between different SAR acquisitions (i.e., tropospheric delay). These effects are particularly limiting in the rural/agricultural setting of the Delta. We demonstrate the usage of InSAR for spatially comprehensive subsidence monitoring both at the scale of the levees and at a scale that captures the intra-island variability. The study uses data collected over a period of six years (2009-2015) with NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) instrument, which is the prototype airborne instrument for the NISAR mission. We mitigate atmospheric noise by estimating a correction from state-of-the-art weather models, and reduce decorrelation noise by utilizing L-band SAR and using advanced time-series InSAR processing methods. Our analysis includes nine UAVSAR flight lines that cover altogether an area of approximately 8500 km2, including the Delta and the surrounding areas.

  17. Application of vector analysis on study of illuminated area and Doppler characteristics of airborne pulse radar

    NASA Astrophysics Data System (ADS)

    Wang, Haijiang; Yang, Ling

    2014-12-01

    In this paper, the application of vector analysis tool in the illuminated area and the Doppler frequency distribution research for the airborne pulse radar is studied. An important feature of vector analysis is that it can closely combine the geometric ideas with algebraic calculations. Through coordinate transform, the relationship between the frame of radar antenna and the ground, under aircraft motion attitude, is derived. Under the time-space analysis, the overlap area between the footprint of radar beam and the pulse-illuminated zone is obtained. Furthermore, the Doppler frequency expression is successfully deduced. In addition, the Doppler frequency distribution is plotted finally. Using the time-space analysis results, some important parameters of a specified airborne radar system are obtained. Simultaneously, the results are applied to correct the phase error brought by attitude change in airborne synthetic aperture radar (SAR) imaging.

  18. James Ross Island captured by NASA photographer James Ross, from NASA's DC-8 aircraft during an AirSAR 2004 mission over the Antarctic Peninsula

    NASA Image and Video Library

    2004-03-16

    James Ross Island captured by NASA photographer James Ross(no relation), from NASA's DC-8 aircraft during an AirSAR 2004 mission over the Antarctic Peninsula. James Ross Island, named for 19th century British polar explorer Sir James Clark Ross, is located at the northern tip of the Antarctic Peninsula. The island is about 1500 m high and 40-60 km wide. In recent decades, the area has experienced significant atmospheric warming (about 2 degrees C since 1950), which has triggered a vast and spectacular retreat of its floating ice shelves, glacier reduction, a decrease in permanent snow cover and a lengthening of the melt season. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. These photos are from the DC-8 aircraft while flying an AirSAR mission over Antarctica. The Antarctic Peninsula is more similar to Alaska and Patagonia than to the rest of the Antarctic continent. It is drained by fast glaciers, receives abundant precipitation, and melts significantly in the summer months. This region is being studied by NASA using a DC-8 equipped with the Airborne Synthetic Aperture Radar developed by scientists from NASA’s Jet Propulsion Laboratory. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  19. This is a photograph from the left side of the aircraft as NASA's DC-8 does an AirSAR 2004 research "line" over Honduras

    NASA Image and Video Library

    2004-03-03

    This is a photograph from the left side of the aircraft as NASA's DC-8 does an AirSAR 2004 research "line" over Honduras. AirSAR 2004 is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  20. SAR imaging of vortex ship wakes. Volume 3: An overview of pre-ERS-1 observations and models

    NASA Astrophysics Data System (ADS)

    Skoeelv, Aage; Wahl, Terje

    1991-05-01

    The visibility of dark turbulent wakes in Synthetic Aperture Radar (SAR) imagery is focused upon. An overview of various wake observations prior to ERS-1 is given. This includes images from Seasat and airborne SAR as well as photographic observations. Different turbulent wake models and simulation, schemes are reviewed. The requirements for a complete turbulent wake model are discussed, and from results available, some conclusions are drawn with respect to possible ERS-1 applications.

  1. Validation of Forested Inundation Extent Revealed by L-Band Polarimetric and Interferometric SAR Data

    NASA Technical Reports Server (NTRS)

    Chapman, Bruce; Celi, Jorge; Hamilton, Steve; McDonald, Kyle

    2013-01-01

    UAVSAR, NASA's airborne Synthetic Aperture Radar (SAR), conducted an extended observational campaign in Central and South America in March 2013, primarily related to volcanic deformations along the Andean Mountain Range but also including a large number of flights studying other scientific phenomena. During this campaign, the L-Band SAR collected data over the Napo River in Ecuador. The objectives of this experiment were to acquire polarimetric and interferometric L-Band SAR data over an inundated tropical forest in Ecuador simultaneously with on-the-ground field work ascertaining the extent of inundation, and to then derive from this data a quantitative estimate for the error in the SAR-derived inundation extent. In this paper, we will first describe the processing and preliminary analysis of the SAR data. The polarimetric SAR data will be classified by land cover and inundation state. The interferometric SAR data will be used to identify those areas where change in inundation extent occurred, and to measure the change in water level between two observations separated by a week. Second, we will describe the collection of the field estimates of inundation, and have preliminary comparisons of inundation extent measured in the field field versus that estimated from the SAR data.

  2. Combined DEM Extration Method from StereoSAR and InSAR

    NASA Astrophysics Data System (ADS)

    Zhao, Z.; Zhang, J. X.; Duan, M. Y.; Huang, G. M.; Yang, S. C.

    2015-06-01

    A pair of SAR images acquired from different positions can be used to generate digital elevation model (DEM). Two techniques exploiting this characteristic have been introduced: stereo SAR and interferometric SAR. They permit to recover the third dimension (topography) and, at the same time, to identify the absolute position (geolocation) of pixels included in the imaged area, thus allowing the generation of DEMs. In this paper, StereoSAR and InSAR combined adjustment model are constructed, and unify DEM extraction from InSAR and StereoSAR into the same coordinate system, and then improve three dimensional positioning accuracy of the target. We assume that there are four images 1, 2, 3 and 4. One pair of SAR images 1,2 meet the required conditions for InSAR technology, while the other pair of SAR images 3,4 can form stereo image pairs. The phase model is based on InSAR rigorous imaging geometric model. The master image 1 and the slave image 2 will be used in InSAR processing, but the slave image 2 is only used in the course of establishment, and the pixels of the slave image 2 are relevant to the corresponding pixels of the master image 1 through image coregistration coefficient, and it calculates the corresponding phase. It doesn't require the slave image in the construction of the phase model. In Range-Doppler (RD) model, the range equation and Doppler equation are a function of target geolocation, while in the phase equation, the phase is also a function of target geolocation. We exploit combined adjustment model to deviation of target geolocation, thus the problem of target solution is changed to solve three unkonwns through seven equations. The model was tested for DEM extraction under spaceborne InSAR and StereoSAR data and compared with InSAR and StereoSAR methods respectively. The results showed that the model delivered a better performance on experimental imagery and can be used for DEM extraction applications.

  3. Design and realization of an active SAR calibrator for TerraSAR-X

    NASA Astrophysics Data System (ADS)

    Dummer, Georg; Lenz, Rainer; Lutz, Benjamin; Kühl, Markus; Müller-Glaser, Klaus D.; Wiesbeck, Werner

    2005-10-01

    TerraSAR-X is a new earth observing satellite which will be launched in spring 2006. It carries a high resolution X-band SAR sensor. For high image data quality, accurate ground calibration targets are necessary. This paper describes a novel system concept for an active and highly integrated, digitally controlled SAR system calibrator. A total of 16 active transponder and receiver systems and 17 receiver only systems will be fabricated for a calibration campaign. The calibration units serve for absolute radiometric calibration of the SAR image data. Additionally, they are equipped with an extra receiver path for two dimensional satellite antenna pattern recognition. The calibrator is controlled by a dedicated digital Electronic Control Unit (ECU). The different voltages needed by the calibrator and the ECU are provided by the third main unit called Power Management Unit (PMU).

  4. airborne data analysis/monitor system

    NASA Technical Reports Server (NTRS)

    Stephison, D. B.

    1981-01-01

    An Airborne Data Analysis/Monitor System (ADAMS), a ROLM 1666 computer based system installed onboard test airplanes used during experimental testing is evaluated. In addition to the 1666 computer, the ADAMS hardware includes a DDC System 90 fixed head disk and a Miltape DD400 floppy disk. Boeing designed a DMA interface to the data acquisition system and an intelligent terminal to reduce system overhead and simplify operator commands. The ADAMS software includes RMX/RTOS and both ROLM FORTRAN and assembly language are used. The ADAMS provides real time displays that enable onboard test engineers to make rapid decisions about test conduct thus reducing the cost and time required to certify new model airplanes, and improved the quality of data derived from the test, leading to more rapid development of improvements resulting in quieter, safer, and more efficient airplanes. The availability of airborne data processing removes most of the weather and geographical restrictions imposed by telemetered flight test data systems. A data base is maintained to describe the airplane, the data acquisition system, the type of testing, and the conditions under which the test is performed.

  5. High-accuracy single-pass InSAR DEM for large-scale flood hazard applications

    NASA Astrophysics Data System (ADS)

    Schumann, G.; Faherty, D.; Moller, D.

    2017-12-01

    In this study, we used a unique opportunity of the GLISTIN-A (NASA airborne mission designed to characterizing the cryosphere) track to Greenland to acquire a high-resolution InSAR DEM of a large area in the Red River of the North Basin (north of Grand Forks, ND, USA), which is a very flood-vulnerable valley, particularly in spring time due to increased soil moisture content near state of saturation and/or, typical for this region, snowmelt. Having an InSAR DEM that meets flood inundation modeling and mapping requirements comparable to LiDAR, would demonstrate great application potential of new radar technology for national agencies with an operational flood forecasting mandate and also local state governments active in flood event prediction, disaster response and mitigation. Specifically, we derived a bare-earth DEM in SAR geometry by first removing the inherent far range bias related to airborne operation, which at the more typical large-scale DEM resolution of 30 m has a sensor accuracy of plus or minus 2.5 cm. Subsequently, an intelligent classifier based on informed relationships between InSAR height, intensity and correlation was used to distinguish between bare-earth, roads or embankments, buildings and tall vegetation in order to facilitate the creation of a bare-earth DEM that would meet the requirements for accurate floodplain inundation mapping. Using state-of-the-art LiDAR terrain data, we demonstrate that capability by achieving a root mean squared error of approximately 25 cm and further illustrating its applicability to flood modeling.

  6. From SARS to strategic actions reframing systems.

    PubMed

    Macdonald, Marilyn T

    2004-09-01

    The developed world responds to new and re-emerging diseases through the discovery of medications. Disease can be transmitted around the world in a day, but the development of medications does not occur at this rate. The world has one environment and the focus in health care must be on identifying factors in this environment that coalesce to produce disease. The aim of this paper is to introduce the integrative model of environmental health and explore its potential to illuminate the Toronto SARS experience. SARS affected people on three continents in a matter of days. Response to this new disease varied from one area to another and was dependent upon the level of integration of health services and communication across services. The present focus of the health care system is on treating the results of disease rather than the causative factors. Reacting to a new disease had grave social and economic consequences. The time for a new global environmental approach to health is now. The Toronto SARS experience was examined using the integrative model of environmental health and the upstream perspective as exemplars to interrupt the traditional approach to disease. All health care providers share the responsibility to learn about and to understand how our environment creates disease. This knowledge comes through research on topics such as; chemicals, pesticides, soil erosion, killing of forests, contamination of water, destabilization of climate, and social disruption from wars. Health care systems in the developed world continue to focus on the treatment of disease. A global ecological initiative for an integrated disease prevention system must be negotiated among nations.

  7. DUSTER: demonstration of an integrated LWIR-VNIR-SAR imaging system

    NASA Astrophysics Data System (ADS)

    Wilson, Michael L.; Linne von Berg, Dale; Kruer, Melvin; Holt, Niel; Anderson, Scott A.; Long, David G.; Margulis, Yuly

    2008-04-01

    The Naval Research Laboratory (NRL) and Space Dynamics Laboratory (SDL) are executing a joint effort, DUSTER (Deployable Unmanned System for Targeting, Exploitation, and Reconnaissance), to develop and test a new tactical sensor system specifically designed for Tier II UAVs. The system is composed of two coupled near-real-time sensors: EyePod (VNIR/LWIR ball gimbal) and NuSAR (L-band synthetic aperture radar). EyePod consists of a jitter-stabilized LWIR sensor coupled with a dual focal-length optical system and a bore-sighted high-resolution VNIR sensor. The dual focal-length design coupled with precision pointing an step-stare capabilities enable EyePod to conduct wide-area survey and high resolution inspection missions from a single flight pass. NuSAR is being developed with partners Brigham Young University (BYU) and Artemis, Inc and consists of a wideband L-band SAR capable of large area survey and embedded real-time image formation. Both sensors employ standard Ethernet interfaces and provide geo-registered NITFS output imagery. In the fall of 2007, field tests were conducted with both sensors, results of which will be presented.

  8. NASA JPL scientists Yunling Lou and Dr. Eric Rignot work on line selection while flying AirSAR missions over the Antarctic Peninsula

    NASA Image and Video Library

    2004-03-16

    NASA JPL scientists Yunling Lou and Dr. Eric Rignot work on line selection while flying AirSAR missions over the Antarctic Peninsula. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. These photos are from the DC-8 aircraft while flying an AirSAR mission over Antarctica. The Antarctic Peninsula is more similar to Alaska and Patagonia than to the rest of the Antarctic continent. It is drained by fast glaciers, receives abundant precipitation, and melts significantly in the summer months. In recent decades, the Peninsula has experienced significant atmospheric warming (about 2 degrees C since 1950), which has triggered a vast and spectacular retreat of its floating ice shelves, glacier reduction, a decrease in permanent snow cover and a lengthening of the melt season. As a result, the contribution to sea level from this region could be rapid and substantial. With an area of 120,000 km, or ten times the Patagonia ice fields, the Peninsula could contribute as much as 0.4mm/yr sea level rise, which would be the largest single contribution to sea level from anywhere in the world. This region is being studied by NASA using a DC-8 equipped with the Airborne Synthetic Aperture Radar developed by scientists from NASA’s Jet Propulsion Laboratory. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  9. DC-8 Quality Inspector Scott Silver signs documents while Acting Crew Chief Mike Bereda looks on prior to a DC-8 AirSAR flight in Costa Rica

    NASA Image and Video Library

    2004-03-06

    DC-8 Quality Inspector Scott Silver signs documents while Acting Crew Chief Mike Bereda looks on prior to a DC-8 AirSAR flight in Costa Rica. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that uses an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central America with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. The radar, developed by NASA's Jet Propulsion Laboratory, can penetrate clouds and also collect data at night. Its high-resolution sensors operate at multiple wavelengths and modes, allowing AirSAR to see beneath treetops, through thin sand, and dry snow pack. AirSAR's 2004 campaign is a collaboration of many U.S. and Central American institutions and scientists, including NASA; the National Science Foundation; the Smithsonian Institution; National Geographic; Conservation International; the Organization of Tropical Studies; the Central American Commission for Environment and Development; and the Inter-American Development Bank.

  10. Agricultural Land Cover from Multitemporal C-Band SAR Data

    NASA Astrophysics Data System (ADS)

    Skriver, H.

    2013-12-01

    Henning Skriver DTU Space, Technical University of Denmark Ørsteds Plads, Building 348, DK-2800 Lyngby e-mail: hs@space.dtu.dk Problem description This paper focuses on land cover type from SAR data using high revisit acquisitions, including single and dual polarisation and fully polarimetric data, at C-band. The data set were acquired during an ESA-supported campaign, AgriSAR09, with the Radarsat-2 system. Ground surveys to obtain detailed land cover maps were performed during the campaign. Classification methods using single- and dual-polarisation data, and fully polarimetric data are used with multitemporal data with short revisit time. Results for airborne campaigns have previously been reported in Skriver et al. (2011) and Skriver (2012). In this paper, the short revisit satellite SAR data will be used to assess the trade-off between polarimetric SAR data and data as single or dual polarisation SAR data. This is particularly important in relation to the future GMES Sentinel-1 SAR satellites, where two satellites with a relatively wide swath will ensure a short revisit time globally. Questions dealt with are: which accuracy can we expect from a mission like the Sentinel-1, what is the improvement of using polarimetric SAR compared to single or dual polarisation SAR, and what is the optimum number of acquisitions needed. Methodology The data have sufficient number of looks for the Gaussian assumption to be valid for the backscatter coefficients for the individual polarizations. The classification method used for these data is therefore the standard Bayesian classification method for multivariate Gaussian statistics. For the full-polarimetric cases two classification methods have been applied, the standard ML Wishart classifier, and a method based on a reversible transform of the covariance matrix into backscatter intensities. The following pre-processing steps were performed on both data sets: The scattering matrix data in the form of SLC products were

  11. Built-up Areas Extraction in High Resolution SAR Imagery based on the method of Multiple Feature Weighted Fusion

    NASA Astrophysics Data System (ADS)

    Liu, X.; Zhang, J. X.; Zhao, Z.; Ma, A. D.

    2015-06-01

    Synthetic aperture radar in the application of remote sensing technology is becoming more and more widely because of its all-time and all-weather operation, feature extraction research in high resolution SAR image has become a hot topic of concern. In particular, with the continuous improvement of airborne SAR image resolution, image texture information become more abundant. It's of great significance to classification and extraction. In this paper, a novel method for built-up areas extraction using both statistical and structural features is proposed according to the built-up texture features. First of all, statistical texture features and structural features are respectively extracted by classical method of gray level co-occurrence matrix and method of variogram function, and the direction information is considered in this process. Next, feature weights are calculated innovatively according to the Bhattacharyya distance. Then, all features are weighted fusion. At last, the fused image is classified with K-means classification method and the built-up areas are extracted after post classification process. The proposed method has been tested by domestic airborne P band polarization SAR images, at the same time, two groups of experiments based on the method of statistical texture and the method of structural texture were carried out respectively. On the basis of qualitative analysis, quantitative analysis based on the built-up area selected artificially is enforced, in the relatively simple experimentation area, detection rate is more than 90%, in the relatively complex experimentation area, detection rate is also higher than the other two methods. In the study-area, the results show that this method can effectively and accurately extract built-up areas in high resolution airborne SAR imagery.

  12. 20. OVERVIEW OF SAR3 COMPLEX, SHOWING FORMER RESIDENTIAL AREA, SAR3 ...

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

    20. OVERVIEW OF SAR-3 COMPLEX, SHOWING FORMER RESIDENTIAL AREA, SAR-3 SWITCH RACK, MAINTENANCE YARD, AND GREENSPOT BRIDGE. NOTE ALSO LARGE PIPE CONDUCTING TAILRACE WATER INTO IRRIGATION SYSTEM. VIEW TO SOUTHWEST. - Santa Ana River Hydroelectric System, Redlands, San Bernardino County, CA

  13. TerraSAR-X mission

    NASA Astrophysics Data System (ADS)

    Werninghaus, Rolf

    2004-01-01

    The TerraSAR-X is a German national SAR- satellite system for scientific and commercial applications. It is the continuation of the scientifically and technologically successful radar missions X-SAR (1994) and SRTM (2000) and will bring the national technology developments DESA and TOPAS into operational use. The space segment of TerraSAR-X is an advanced high-resolution X-Band radar satellite. The system design is based on a sound market analysis performed by Infoterra. The TerraSAR-X features an advanced high-resolution X-Band Synthetic Aperture Radar based on the active phased array technology which allows the operation in Spotlight-, Stripmap- and ScanSAR Mode with various polarizations. It combines the ability to acquire high resolution images for detailed analysis as well as wide swath images for overview applications. In addition, experimental modes like the Dual Receive Antenna Mode allow for full-polarimetric imaging as well as along track interferometry, i.e. moving target identification. The Ground Segment is optimized for flexible response to (scientific and commercial) User requests and fast image product turn-around times. The TerraSAR-X mission will serve two main goals. The first goal is to provide the strongly supportive scientific community with multi-mode X-Band SAR data. The broad spectrum of scientific application areas include Hydrology, Geology, Climatology, Oceanography, Environmental Monitoring and Disaster Monitoring as well as Cartography (DEM Generation) and Interferometry. The second goal is the establishment of a commercial EO-market in Europe which is driven by Infoterra. The commercial goal is the development of a sustainable EO-business so that the e.g. follow-on systems can be completely financed by industry from the profit. Due to its commercial potential, the TerraSAR-X project will be implemented based on a public-private partnership with the Astrium GmbH. This paper will describe first the mission objectives as well as the

  14. 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

  15. Alternative synthetic aperture radar (SAR) modalities using a 1D dynamic metasurface antenna

    NASA Astrophysics Data System (ADS)

    Boyarsky, Michael; Sleasman, Timothy; Pulido-Mancera, Laura; Imani, Mohammadreza F.; Reynolds, Matthew S.; Smith, David R.

    2017-05-01

    Synthetic aperture radar (SAR) systems conventionally rely on mechanically-actuated reflector dishes or large phased arrays for generating steerable directive beams. While these systems have yielded high-resolution images, the hardware suffers from considerable weight, high cost, substantial power consumption, and moving parts. Since these disadvantages are particularly relevant in airborne and spaceborne systems, a flat, lightweight, and low-cost solution is a sought-after goal. Dynamic metasurface antennas have emerged as a recent technology for generating waveforms with desired characteristics. Metasurface antennas consist of an electrically-large waveguide loaded with numerous subwavelength radiators which selectively leak energy from a guided wave into free space to form various radiation patterns. By tuning each radiating element, we can modulate the aperture's overall radiation pattern to generate steered directive beams, without moving parts or phase shifters. Furthermore, by using established manufacturing methods, these apertures can be made to be lightweight, low-cost, and planar, while maintaining high performance. In addition to their hardware benefits, dynamic metasurfaces can leverage their dexterity and high switching speeds to enable alternative SAR modalities for improved performance. In this work, we briefly discuss how dynamic metasurfaces can conduct existing SAR modalities with similar performance as conventional systems from a significantly simpler hardware platform. We will also describe two additional modalities which may achieve improved performance as compared to traditional modalities. These modalities, enhanced resolution stripmap and diverse pattern stripmap, offer the ability to circumvent the trade-off between resolution and region-of-interest size that exists within stripmap and spotlight. Imaging results with a simulated dynamic metasurface verify the benefits of these modalities and a discussion of implementation considerations

  16. Safety analysis and review system (SARS) assessment report

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

    Browne, E.T.

    1981-03-01

    Under DOE Order 5481.1, Safety Analysis and Review System for DOE Operations, safety analyses are required for DOE projects in order to ensure that: (1) potential hazards are systematically identified; (2) potential impacts are analyzed; (3) reasonable measures have been taken to eliminate, control, or mitigate the hazards; and (4) there is documented management authorization of the DOE operation based on an objective assessment of the adequacy of the safety analysis. This report is intended to provide the DOE Office of Plans and Technology Assessment (OPTA) with an independent evaluation of the adequacy of the ongoing safety analysis effort. Asmore » part of this effort, a number of site visits and interviews were conducted, and FE SARS documents were reviewed. The latter included SARS Implementation Plans for a number of FE field offices, as well as safety analysis reports completed for certain FE operations. This report summarizes SARS related efforts at the DOE field offices visited and evaluates the extent to which they fulfill the requirements of DOE 5481.1.« less

  17. SAR calibration technology review

    NASA Technical Reports Server (NTRS)

    Walker, J. L.; Larson, R. W.

    1981-01-01

    Synthetic Aperture Radar (SAR) calibration technology including a general description of the primary calibration techniques and some of the factors which affect the performance of calibrated SAR systems are reviewed. The use of reference reflectors for measurement of the total system transfer function along with an on-board calibration signal generator for monitoring the temporal variations of the receiver to processor output is a practical approach for SAR calibration. However, preliminary error analysis and previous experimental measurements indicate that reflectivity measurement accuracies of better than 3 dB will be difficult to achieve. This is not adequate for many applications and, therefore, improved end-to-end SAR calibration techniques are required.

  18. An AirSAR 2004 view from the DC-8 as it approaches the Larsen Ice Shelf, which is part of the Antarctic Peninsula

    NASA Image and Video Library

    2004-03-13

    An AirSAR 2004 view from the DC-8 as it approaches the Larsen Ice Shelf, which is part of the Antarctic Peninsula. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. These photos are from the DC-8 aircraft while flying an AirSAR mission over Antarctica. The Antarctic Peninsula is more similar to Alaska and Patagonia than to the rest of the Antarctic continent. It is drained by fast glaciers, receives abundant precipitation, and melts significantly in the summer months. In recent decades, the Peninsula has experienced significant atmospheric warming (about 2 degrees C since 1950), which has triggered a vast and spectacular retreat of its floating ice shelves, glacier reduction, a decrease in permanent snow cover and a lengthening of the melt season. As a result, the contribution to sea level from this region could be rapid and substantial. With an area of 120,000 km, or ten times the Patagonia ice fields, the Peninsula could contribute as much as 0.4mm/yr sea level rise, which would be the largest single contribution to sea level from anywhere in the world. This region is being studied by NASA using a DC-8 equipped with the Airborne Synthetic Aperture Radar developed by scientists from NASA’s Jet Propulsion Laboratory. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  19. Exploitation of Digital Surface Models Generated from WORLDVIEW-2 Data for SAR Simulation Techniques

    NASA Astrophysics Data System (ADS)

    Ilehag, R.; Auer, S.; d'Angelo, P.

    2017-05-01

    GeoRaySAR, an automated SAR simulator developed at DLR, identifies buildings in high resolution SAR data by utilizing geometric knowledge extracted from digital surface models (DSMs). Hitherto, the simulator has utilized DSMs generated from LiDAR data from airborne sensors with pre-filtered vegetation. Discarding the need for pre-optimized model input, DSMs generated from high resolution optical data (acquired with WorldView-2) are used for the extraction of building-related SAR image parts in this work. An automatic preprocessing of the DSMs has been developed for separating buildings from elevated vegetation (trees, bushes) and reducing the noise level. Based on that, automated simulations are triggered considering the properties of real SAR images. Locations in three cities, Munich, London and Istanbul, were chosen as study areas to determine advantages and limitations related to WorldView-2 DSMs as input for GeoRaySAR. Beyond, the impact of the quality of the DSM in terms of building extraction is evaluated as well as evaluation of building DSM, a DSM only containing buildings. The results indicate that building extents can be detected with DSMs from optical satellite data with various success, dependent on the quality of the DSM as well as on the SAR imaging perspective.

  20. SAR System for UAV Operation with Motion Error Compensation beyond the Resolution Cell

    PubMed Central

    González-Partida, José-Tomás; Almorox-González, Pablo; Burgos-García, Mateo; Dorta-Naranjo, Blas-Pablo

    2008-01-01

    This paper presents an experimental Synthetic Aperture Radar (SAR) system that is under development in the Universidad Politécnica de Madrid. The system uses Linear Frequency Modulated Continuous Wave (LFM-CW) radar with a two antenna configuration for transmission and reception. The radar operates in the millimeter-wave band with a maximum transmitted bandwidth of 2 GHz. The proposed system is being developed for Unmanned Aerial Vehicle (UAV) operation. Motion errors in UAV operation can be critical. Therefore, this paper proposes a method for focusing SAR images with movement errors larger than the resolution cell. Typically, this problem is solved using two processing steps: first, coarse motion compensation based on the information provided by an Inertial Measuring Unit (IMU); and second, fine motion compensation for the residual errors within the resolution cell based on the received raw data. The proposed technique tries to focus the image without using data of an IMU. The method is based on a combination of the well known Phase Gradient Autofocus (PGA) for SAR imagery and typical algorithms for translational motion compensation on Inverse SAR (ISAR). This paper shows the first real experiments for obtaining high resolution SAR images using a car as a mobile platform for our radar. PMID:27879884

  1. SAR System for UAV Operation with Motion Error Compensation beyond the Resolution Cell.

    PubMed

    González-Partida, José-Tomás; Almorox-González, Pablo; Burgos-Garcia, Mateo; Dorta-Naranjo, Blas-Pablo

    2008-05-23

    This paper presents an experimental Synthetic Aperture Radar (SAR) system that is under development in the Universidad Politécnica de Madrid. The system uses Linear Frequency Modulated Continuous Wave (LFM-CW) radar with a two antenna configuration for transmission and reception. The radar operates in the millimeter-wave band with a maximum transmitted bandwidth of 2 GHz. The proposed system is being developed for Unmanned Aerial Vehicle (UAV) operation. Motion errors in UAV operation can be critical. Therefore, this paper proposes a method for focusing SAR images with movement errors larger than the resolution cell. Typically, this problem is solved using two processing steps: first, coarse motion compensation based on the information provided by an Inertial Measuring Unit (IMU); and second, fine motion compensation for the residual errors within the resolution cell based on the received raw data. The proposed technique tries to focus the image without using data of an IMU. The method is based on a combination of the well known Phase Gradient Autofocus (PGA) for SAR imagery and typical algorithms for translational motion compensation on Inverse SAR (ISAR). This paper shows the first real experiments for obtaining high resolution SAR images using a car as a mobile platform for our radar.

  2. Assessment of documentation requirements under DOE 5481. 1, Safety Analysis and Review System (SARS)

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

    Browne, E.T.

    1981-03-01

    This report assesses the requirements of DOE Order 5481.1, Safety Analysis and Review System for DOE Operations (SARS) in regard to maintaining SARS documentation. Under SARS, all pertinent details of the entire safety analysis and review process for each DOE operation are to be traceable from the initial identification of a hazard. This report is intended to provide assistance in identifying the points in the SARS cycle at which documentation is required, what type of documentation is most appropriate, and where it ultimately should be maintained.

  3. Detection of land degradation with polarimetric SAR

    NASA Technical Reports Server (NTRS)

    Ray, Terrill W.; Farr, Tom G.; Van Zyl, Jakob J.

    1992-01-01

    Multispectral radar polarimeter data were collected over the Manix Basin Area of the Mojave desert using an airborne SAR. An analysis of the data reveals unusual polarization responses which are attributed to the formation of wind ripples on the surfaces of fields that have been abandoned for more than 5 years. This hypothesis has been confirmed through field observations, and a second-order perturbation model is shown to effectively model the polarization responses. The results demonstrate the usefulness of remote sensing techniques for the study of land degradation at synoptic scales.

  4. Materiel requirements for airborne minefield detection system

    NASA Astrophysics Data System (ADS)

    Bertsche, Karl A.; Huegle, Helmut

    1997-07-01

    Within the concept study, Material Requirements for an airborne minefield detection systems (AMiDS) the following topics were investigated: (i) concept concerning airborne minefield detection technique sand equipment, (ii) verification analysis of the AMiDS requirements using simulation models and (iii) application concept of AMiDS with regard o tactics and military operations. In a first approach the problems concerning unmanned airborne minefield detection techniques within a well-defined area were considered. The complexity of unmanned airborne minefield detection is a result of the following parameters: mine types, mine deployment methods, tactical requirements, topography, weather conditions, and the size of the area to be searched. In order to perform the analysis, a simulation model was developed to analyze the usability of the proposed remote controlled air carriers. The basic flight patterns for the proposed air carriers, as well as the preparation efforts of military operations and benefits of such a system during combat support missions were investigated. The results of the conceptual study showed that a proposed remote controlled helicopter drone could meet the stated German MOD scanning requirements of mine barriers. Fixed wing air carriers were at a definite disadvantage because of their inherently large turning loops. By implementing a mine detection system like AMiDS minefields can be reconnoitered before an attack. It is therefore possible either to plan, how the minefields can be circumvented or where precisely breaching lanes through the mine barriers are to be cleared for the advancing force.

  5. Sea Ice Thickness Estimates from Data Collected Using Airborne Sensors and Coincident In Situ Data

    NASA Astrophysics Data System (ADS)

    Gardner, J. M.; Brozena, J. M.; Abelev, A.; Hagen, R. A.; Liang, R.; Ball, D.

    2016-12-01

    The Naval Research Laboratory collected data using Airborne sensors and coincident in-situ measurements over multiple sites of floating, but land-fast ice north of Barrow, AK. The in-situ data provide ground-truth for airborne measurements from a scanning LiDAR (Riegl Q 560i), digital photogrammetry (Applanix DSS-439), a low-frequency SAR (P-band in 2014 and P and L bands in 2015 and 2016) and a snow/Ku radar procured from the Center for Remote Sensing of Ice Sheets of the University of Kansas. The CReSIS radar was updated in 2015 to integrate the snow and Ku radars into a single continuous chirp, thus improving resolution. The objective of the surveys was to aid our understanding of the accuracy of ice thickness estimation via the freeboard method using the airborne sensor suite. Airborne data were collected on multiple overflights of the transect areas. The LiDAR measured total freeboard (ice + snow) referenced to leads in the ice, and produced swaths 200-300 m wide. The SAR imaged the ice beneath the snow and the snow/Ku radar measured snow thickness. The freeboard measurements and snow thickness are used to estimate ice thickness via isostasy and density estimates. Comparisons and processing methodology will be shown using data from three field seasons (2014-2016). The results of this ground-truth experiment will inform our analysis of grids of airborne data collected over areas of sea-ice illuminated by Cryosat-2.

  6. A Modular and Configurable Instrument Electronics Architecture for "MiniSAR"- An Advanced Smallsat SAR Instrument

    NASA Astrophysics Data System (ADS)

    Gomez, Jaime; Pastena, Max; Bierens, Laurens

    2013-08-01

    MiniSAR is a Dutch program focused on the development of a commercial smallsat featuring a SAR instrument, led by SSBV as prime contractor. In this paper an Instrument Electronics (IEL) system concept to meet the MiniSAR demands is presented. This system has several specificities wrt similar initiatives in the European space industry, driven by our main requirement: keep it small.

  7. Curvelet-based compressive sensing for InSAR raw data

    NASA Astrophysics Data System (ADS)

    Costa, Marcello G.; da Silva Pinho, Marcelo; Fernandes, David

    2015-10-01

    The aim of this work is to evaluate the compression performance of SAR raw data for interferometry applications collected by airborne from BRADAR (Brazilian SAR System operating in X and P bands) using the new approach based on compressive sensing (CS) to achieve an effective recovery with a good phase preserving. For this framework is desirable a real-time capability, where the collected data can be compressed to reduce onboard storage and bandwidth required for transmission. In the CS theory, a sparse unknown signals can be recovered from a small number of random or pseudo-random measurements by sparsity-promoting nonlinear recovery algorithms. Therefore, the original signal can be significantly reduced. To achieve the sparse representation of SAR signal, was done a curvelet transform. The curvelets constitute a directional frame, which allows an optimal sparse representation of objects with discontinuities along smooth curves as observed in raw data and provides an advanced denoising optimization. For the tests were made available a scene of 8192 x 2048 samples in range and azimuth in X-band with 2 m of resolution. The sparse representation was compressed using low dimension measurements matrices in each curvelet subband. Thus, an iterative CS reconstruction method based on IST (iterative soft/shrinkage threshold) was adjusted to recover the curvelets coefficients and then the original signal. To evaluate the compression performance were computed the compression ratio (CR), signal to noise ratio (SNR), and because the interferometry applications require more reconstruction accuracy the phase parameters like the standard deviation of the phase (PSD) and the mean phase error (MPE) were also computed. Moreover, in the image domain, a single-look complex image was generated to evaluate the compression effects. All results were computed in terms of sparsity analysis to provides an efficient compression and quality recovering appropriated for inSAR applications

  8. Foldbelt exploration with synthetic aperture radar (SAR) in Papua New Guinea

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

    Ellis, J.M.; Pruett, F.D.

    1987-05-01

    Synthetic aperture radar (SAR) is being successfully used within the southern fold and thrust belt of Papua New Guinea to map surface structure and stratigraphy and to help plan a hydrocarbon exploration program. The airborne SAR imagery, along with other surface data, is used as a primary exploration tool because acquisition of acceptable seismic data is extremely costly due to extensive outcrops of Tertiary Darai Limestone which develops rugged karst topography. Most anticlines in the licenses are capped with this deeply karstified limestone. The region is ideally suited to geologic analysis using remote sensing technology. The area is seldom cloudmore » free and is covered with tropical rain forest, and geologic field studies are limited. The widespread karst terrain is exceedingly dangerous, if not impossible, to traverse on the ground. SAR is used to guide ongoing field work, modeling of subsurface structure, and selection of well locations. SAR provides their explorationists with an excellent data base because (1) structure is enhanced with low illumination, (2) resolution is 6 x 12 m, (3) digital reprocessing is possible, (4) clouds are penetrated by the SAR, and (5) the survey was designed for stereoscopic photogeology. Landsat images and vertical aerial photographs complement SAR but provide subdued structural information because of minimal shadowing (due to high sun angles) and the jungle cover. SAR imagery reveals large-scale mass wasting that has led to a reevaluation of previously acquired field data. Lithologies can be recognized by textural and tonal changes on the SAR images despite near-continuous canopy of jungle. Reprocessing and contrast stretching of the digital radar imagery provide additional geologic information.« less

  9. Airborne Turbulence Detection System Certification Tool Set

    NASA Technical Reports Server (NTRS)

    Hamilton, David W.; Proctor, Fred H.

    2006-01-01

    A methodology and a corresponding set of simulation tools for testing and evaluating turbulence detection sensors has been presented. The tool set is available to industry and the FAA for certification of radar based airborne turbulence detection systems. The tool set consists of simulated data sets representing convectively induced turbulence, an airborne radar simulation system, hazard tables to convert the radar observable to an aircraft load, documentation, a hazard metric "truth" algorithm, and criteria for scoring the predictions. Analysis indicates that flight test data supports spatial buffers for scoring detections. Also, flight data and demonstrations with the tool set suggest the need for a magnitude buffer.

  10. Airborne multicamera system for geo-spatial applications

    NASA Astrophysics Data System (ADS)

    Bachnak, Rafic; Kulkarni, Rahul R.; Lyle, Stacey; Steidley, Carl W.

    2003-08-01

    Airborne remote sensing has many applications that include vegetation detection, oceanography, marine biology, geographical information systems, and environmental coastal science analysis. Remotely sensed images, for example, can be used to study the aftermath of episodic events such as the hurricanes and floods that occur year round in the coastal bend area of Corpus Christi. This paper describes an Airborne Multi-Spectral Imaging System that uses digital cameras to provide high resolution at very high rates. The software is based on Delphi 5.0 and IC Imaging Control's ActiveX controls. Both time and the GPS coordinates are recorded. Three successful test flights have been conducted so far. The paper present flight test results and discusses the issues being addressed to fully develop the system.

  11. Tie Points Extraction for SAR Images Based on Differential Constraints

    NASA Astrophysics Data System (ADS)

    Xiong, X.; Jin, G.; Xu, Q.; Zhang, H.

    2018-04-01

    Automatically extracting tie points (TPs) on large-size synthetic aperture radar (SAR) images is still challenging because the efficiency and correct ratio of the image matching need to be improved. This paper proposes an automatic TPs extraction method based on differential constraints for large-size SAR images obtained from approximately parallel tracks, between which the relative geometric distortions are small in azimuth direction and large in range direction. Image pyramids are built firstly, and then corresponding layers of pyramids are matched from the top to the bottom. In the process, the similarity is measured by the normalized cross correlation (NCC) algorithm, which is calculated from a rectangular window with the long side parallel to the azimuth direction. False matches are removed by the differential constrained random sample consensus (DC-RANSAC) algorithm, which appends strong constraints in azimuth direction and weak constraints in range direction. Matching points in the lower pyramid images are predicted with the local bilinear transformation model in range direction. Experiments performed on ENVISAT ASAR and Chinese airborne SAR images validated the efficiency, correct ratio and accuracy of the proposed method.

  12. Confirmation of quasi-static approximation in SAR evaluation for a wireless power transfer system.

    PubMed

    Hirata, Akimasa; Ito, Fumihiro; Laakso, Ilkka

    2013-09-07

    The present study discusses the applicability of the magneto-quasi-static approximation to the calculation of the specific absorption rate (SAR) in a cylindrical model for a wireless power transfer system. Resonant coils with different parameters were considered in the 10 MHz band. A two-step quasi-static method that is comprised of the method of moments and the scalar-potential finite-difference methods is applied, which can consider the effects of electric and magnetic fields on the induced SAR separately. From our computational results, the SARs obtained from our quasi-static method are found to be in good agreement with full-wave analysis for different positions of the cylindrical model relative to the wireless power transfer system, confirming the applicability of the quasi-static approximation in the 10 MHz band. The SAR induced by the external electric field is found to be marginal as compared to that induced by the magnetic field. Thus, the dosimetry for the external magnetic field, which may be marginally perturbed by the presence of biological tissue, is confirmed to be essential for SAR compliance in the 10 MHz band or lower. This confirmation also suggests that the current in the coil rather than the transferred power is essential for SAR compliance.

  13. 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.

  14. Investigation of ionospheric effects on SAR Interferometry (InSAR): A case study of Hong Kong

    NASA Astrophysics Data System (ADS)

    Zhu, Wu; Ding, Xiao-Li; Jung, Hyung-Sup; Zhang, Qin; Zhang, Bo-Chen; Qu, Wei

    2016-08-01

    Synthetic Aperture Radar Interferometry (InSAR) has demonstrated its potential for high-density spatial mapping of ground displacement associated with earthquakes, volcanoes, and other geologic processes. However, this technique may be affected by the ionosphere, which can result in the distortions of Synthetic Aperture Radar (SAR) images, phases, and polarization. Moreover, ionospheric effect has become and is becoming further significant with the increasing interest in low-frequency SAR systems, limiting the further development of InSAR technique. Although some research has been carried out, thorough analysis of ionospheric influence on true SAR imagery is still limited. Based on this background, this study performs a thorough investigation of ionospheric effect on InSAR through processing L-band ALOS-1/PALSAR-1 images and dual-frequency Global Positioning System (GPS) data over Hong Kong, where the phenomenon of ionospheric irregularities often occurs. The result shows that the small-scale ionospheric irregularities can cause the azimuth pixel shifts and phase advance errors on interferograms. Meanwhile, it is found that these two effects result in the stripe-shaped features in InSAR images. The direction of the stripe-shaped effects keep approximately constant in space for our InSAR dataset. Moreover, the GPS-derived rate of total electron content change index (ROTI), an index to reflect the level of ionospheric disturbances, may be a useful indicator for predicting the ionospheric effect for SAR images. This finding can help us evaluate the quality of SAR images when considering the ionospheric effect.

  15. Synthetic Aperture Radar (SAR) data processing

    NASA Technical Reports Server (NTRS)

    Beckner, F. L.; Ahr, H. A.; Ausherman, D. A.; Cutrona, L. J.; Francisco, S.; Harrison, R. E.; Heuser, J. S.; Jordan, R. L.; Justus, J.; Manning, B.

    1978-01-01

    The available and optimal methods for generating SAR imagery for NASA applications were identified. The SAR image quality and data processing requirements associated with these applications were studied. Mathematical operations and algorithms required to process sensor data into SAR imagery were defined. The architecture of SAR image formation processors was discussed, and technology necessary to implement the SAR data processors used in both general purpose and dedicated imaging systems was addressed.

  16. Predictive models of control strategies involved in containing indoor airborne infections.

    PubMed

    Chen, S-C; Chang, C-F; Liao, C-M

    2006-12-01

    Recently developed control measure modeling approaches for containing airborne infections, including engineering controls with respiratory protection and public health interventions, are readily amenable to an integrated-scale analysis. Here we show that such models can be derived from an integrated-scale analysis generated from three different types of functional relationship: Wells-Riley mathematical model, competing-risks model, and Von Foerster equation, both of the key epidemiological determinants involved and of the functional connections between them. We examine mathematically the impact of engineering control measures such as enhanced air exchange and air filtration rates with personal masking combined with public health interventions such as vaccination, isolation, and contact tracing in containing the spread of indoor airborne infections including influenza, chickenpox, measles, and severe acute respiratory syndrome (SARS). If enhanced engineering controls could reduce the basic reproductive number (R0) below 1.60 for chickenpox and 3 for measles, our simulations show that in such a prepared response with public health interventions would have a high probability of containing the indoor airborne infections. Combinations of engineering control measures and public health interventions could moderately contain influenza strains with an R0 as high as 4. Our analysis indicates that effective isolation of symptomatic patients with low-efficacy contact tracing is sufficient to control a SARS outbreak. We suggest that a valuable added dimension to public health inventions could be provided by systematically quantifying transmissibility and proportion of asymptomatic infection of indoor airborne infection. Practical Implications We have developed a flexible mathematical model that can help determine the best intervention strategies for containing indoor airborne infections. The approach presented here is scalable and can be extended to include additional control

  17. SAR in human head model due to resonant wireless power transfer system.

    PubMed

    Zhang, Chao; Liu, Guoqiang; Li, Yanhong; Song, Xianjin

    2016-04-29

    Efficient mid-range wireless power transfer between transmitter and the receiver has been achieved based on the magnetic resonant coupling method. The influence of electromagnetic field on the human body due to resonant wireless power transfer system (RWPT) should be taken into account during the design process of the system. To analyze the transfer performance of the RWPT system and the change rules of the specific absorption rate (SAR) in the human head model due to the RWPT system. The circuit-field coupling method for a RWPT system with consideration of the displacement current was presented. The relationship between the spiral coil parameters and transfer performance was studied. The SAR in the human head model was calculated under two different exposure conditions. A system with output power higher than 10 W at 0.2 m distance operating at a frequency of approximately 1 MHz was designed. The FEM simulation results show the peak SAR value is below the safety limit which appeared when the human head model is in front of the transmitter. The simulation results agreed well with the experimental results, which verified the validity of the analysis and design.

  18. 23. OVERVIEW OF SAR3 AREA, SHOWING CORNER OF SAR3 WITH ...

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

    23. OVERVIEW OF SAR-3 AREA, SHOWING CORNER OF SAR-3 WITH TAILRACE, ADMINISTRATIVE OFFICE, TOILET SHED, AND RETAINING WALLS AT FORMER EMPLOYEE HOUSING SITE. VIEW TO SOUTHEAST. PANORAMA 1/2. - Santa Ana River Hydroelectric System, Redlands, San Bernardino County, CA

  19. NASA DC-8 Mission Manager Walter Klein and Chilean Air Force Advisor Captain Saez review maps of the Antarctic Peninsula during an AirSAR 2004 mission

    NASA Image and Video Library

    2004-03-13

    NASA DC-8 Mission Manager Walter Klein and Chilean Air Force Advisor Captain Saez review maps of the Antarctic Peninsula during an AirSAR 2004 mission. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. These photos are from the DC-8 aircraft while flying an AirSAR mission over Antarctica. The Antarctic Peninsula is more similar to Alaska and Patagonia than to the rest of the Antarctic continent. It is drained by fast glaciers, receives abundant precipitation, and melts significantly in the summer months. In recent decades, the Peninsula has experienced significant atmospheric warming (about 2 degrees C since 1950), which has triggered a vast and spectacular retreat of its floating ice shelves, glacier reduction, a decrease in permanent snow cover and a lengthening of the melt season. As a result, the contribution to sea level from this region could be rapid and substantial. With an area of 120,000 km, or ten times the Patagonia ice fields, the Peninsula could contribute as much as 0.4mm/yr sea level rise, which would be the largest single contribution to sea level from anywhere in the world. This region is being studied by NASA using a DC-8 equipped with the Airborne Synthetic Aperture Radar developed by scientists from NASA’s Jet Propulsion Laboratory. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

  20. Controls on slow-moving landslides revealed by satellite and airborne InSAR

    NASA Astrophysics Data System (ADS)

    Handwerger, Alexander L.; Fielding, Eric J.

    2017-04-01

    Landslides display a wide variety of behaviors ranging from slow persistent motion to rapid acceleration and catastrophic failure. Given the variety of possible behaviors, improvements to our understanding of landslide mechanics are critical for accurate predictions of landslide dynamics. To better constrain the mechanisms that control landslide motion, we use recent SAR data collected by Copernicus Sentinel-1A/B, NASA UAVSAR, JAXA ALOS-2, and DLR TerraSAR-X to quantify the time-dependent kinematics of over 200 slow-moving landslides in the Central and Northern California Coast Ranges. These landslides are ideally suited for InSAR investigations due to their size (up to 5 km in length and 0.5 km in width), persistent downslope motion with low velocities (m/yr), and sparse vegetation. We quantify the seasonal and multi-year changes in velocity driven by changes in precipitation and find that landslide velocity varies over both timescales. Over seasonal timescales, each landslide displays a period of acceleration that occurs within weeks of the onset of seasonal rainfall suggesting that motion is governed by precipitation-induced changes in pore-water pressure. We also examine the effects of multi-year climate variations (i.e., recent historic California drought and the possible wet period that began in late 2016) on the activity of landslides. We find that the drought has led to a decrease in annual displacement over the past several years and predict that a resurgence in annual displacement will occur with an increase in annual rainfall. Lastly, we use UAVSAR data acquired at 4 different look directions to quantify 3D surface displacement of multiple landslides and invert for their subsurface geometry (i.e. basal slip surface) using recently developed 3D mass conservation techniques. The application of NASA's UAVSAR data represents a major advance from previous InSAR studies on landslides in this region and provides one of the first 3D dataset that contains

  1. ESA airborne campaigns in support of Earth Explorers

    NASA Astrophysics Data System (ADS)

    Casal, Tania; Davidson, Malcolm; Schuettemeyer, Dirk; Perrera, Andrea; Bianchi, Remo

    2013-04-01

    In the framework of its Earth Observation Programmes the European Space Agency (ESA) carries out ground based and airborne campaigns to support geophysical algorithm development, calibration/validation, simulation of future spaceborne earth observation missions, and applications development related to land, oceans and atmosphere. ESA has been conducting airborne and ground measurements campaigns since 1981 by deploying a broad range of active and passive instrumentation in both the optical and microwave regions of the electromagnetic spectrum such as lidars, limb/nadir sounding interferometers/spectrometers, high-resolution spectral imagers, advanced synthetic aperture radars, altimeters and radiometers. These campaigns take place inside and outside Europe in collaboration with national research organisations in the ESA member states as well as with international organisations harmonising European campaign activities. ESA campaigns address all phases of a spaceborne missions, from the very beginning of the design phase during which exploratory or proof-of-concept campaigns are carried out to the post-launch exploitation phase for calibration and validation. We present four recent campaigns illustrating the objectives and implementation of such campaigns. Wavemill Proof Of Concept, an exploratory campaign to demonstrate feasibility of a future Earth Explorer (EE) mission, took place in October 2011 in the Liverpool Bay area in the UK. The main objectives, successfully achieved, were to test Astrium UKs new airborne X-band SAR instrument capability to obtain high resolution ocean current and topology retrievals. Results showed that new airborne instrument is able to retrieve ocean currents to an accuracy of ± 10 cms-1. The IceSAR2012 campaign was set up to support of ESA's EE Candidate 7,BIOMASS. Its main objective was to document P-band radiometric signatures over ice-sheets, by upgrading ESA's airborne POLARIS P-band radar ice sounder with SAR capability. Campaign

  2. 5. SWITCH TOWER AND JUNCTION OF S.A.R. #1 & S.A.R. ...

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

    5. SWITCH TOWER AND JUNCTION OF S.A.R. #1 & S.A.R. #2 TRANSMISSION LINES, MARCH 7, 1916. SCE drawing no. 4932. - Santa Ana River Hydroelectric System, Transmission Lines, Redlands, San Bernardino County, CA

  3. An ice-motion tracking system at the Alaska SAR facility

    NASA Technical Reports Server (NTRS)

    Kwok, Ronald; Curlander, John C.; Pang, Shirley S.; Mcconnell, Ross

    1990-01-01

    An operational system for extracting ice-motion information from synthetic aperture radar (SAR) imagery is being developed as part of the Alaska SAR Facility. This geophysical processing system (GPS) will derive ice-motion information by automated analysis of image sequences acquired by radars on the European ERS-1, Japanese ERS-1, and Canadian RADARSAT remote sensing satellites. The algorithm consists of a novel combination of feature-based and area-based techniques for the tracking of ice floes that undergo translation and rotation between imaging passes. The system performs automatic selection of the image pairs for input to the matching routines using an ice-motion estimator. It is designed to have a daily throughput of ten image pairs. A description is given of the GPS system, including an overview of the ice-motion-tracking algorithm, the system architecture, and the ice-motion products that will be available for distribution to geophysical data users.

  4. Onboard FPGA-based SAR processing for future spaceborne systems

    NASA Technical Reports Server (NTRS)

    Le, Charles; Chan, Samuel; Cheng, Frank; Fang, Winston; Fischman, Mark; Hensley, Scott; Johnson, Robert; Jourdan, Michael; Marina, Miguel; Parham, Bruce; hide

    2004-01-01

    We present a real-time high-performance and fault-tolerant FPGA-based hardware architecture for the processing of synthetic aperture radar (SAR) images in future spaceborne system. In particular, we will discuss the integrated design approach, from top-level algorithm specifications and system requirements, design methodology, functional verification and performance validation, down to hardware design and implementation.

  5. Monitoring of environmental conditions in the Alaskan forests using ERS-1 SAR data

    NASA Technical Reports Server (NTRS)

    Rignot, Eric; Way, Jobea; Mcdonald, Kyle; Viereck, Leslie; Adams, Phyllis

    1992-01-01

    Preliminary results from an analysis of the multitemporal radar backscatter signatures of tree species acquired by European Remote Sensing Satellite (ERS-1) synthetic aperture radar (SAR) data are presented. Significant changes in radar backscatter are detected. Correlation of these differences with ground truth observations indicate that these are due to changes in soil and liquid water content as a result of freeze/thaw events. C-band observations acquired by the NASA/Jet Propulsion Laboratory Airborne SAR (JPL AIRSAR) instrument demonstrate the potential of a C-band radar instrument to monitor drought/flood events. The potential of ERS-1 for monitoring phenologic changes in the forest and for classifying tree species is less promising.

  6. A Cloud-Based System for Automatic Hazard Monitoring from Sentinel-1 SAR Data

    NASA Astrophysics Data System (ADS)

    Meyer, F. J.; Arko, S. A.; Hogenson, K.; McAlpin, D. B.; Whitley, M. A.

    2017-12-01

    Despite the all-weather capabilities of Synthetic Aperture Radar (SAR), and its high performance in change detection, the application of SAR for operational hazard monitoring was limited in the past. This has largely been due to high data costs, slow product delivery, and limited temporal sampling associated with legacy SAR systems. Only since the launch of ESA's Sentinel-1 sensors have routinely acquired and free-of-charge SAR data become available, allowing—for the first time—for a meaningful contribution of SAR to disaster monitoring. In this paper, we present recent technical advances of the Sentinel-1-based SAR processing system SARVIEWS, which was originally built to generate hazard products for volcano monitoring centers. We outline the main functionalities of SARVIEWS including its automatic database interface to Sentinel-1 holdings of the Alaska Satellite Facility (ASF), and its set of automatic processing techniques. Subsequently, we present recent system improvements that were added to SARVIEWS and allowed for a vast expansion of its hazard services; specifically: (1) In early 2017, the SARVIEWS system was migrated into the Amazon Cloud, providing access to cloud capabilities such as elastic scaling of compute resources and cloud-based storage; (2) we co-located SARVIEWS with ASF's cloud-based Sentinel-1 archive, enabling the efficient and cost effective processing of large data volumes; (3) we integrated SARVIEWS with ASF's HyP3 system (http://hyp3.asf.alaska.edu/), providing functionality such as subscription creation via API or map interface as well as automatic email notification; (4) we automated the production chains for seismic and volcanic hazards by integrating SARVIEWS with the USGS earthquake notification service (ENS) and the USGS eruption alert system. Email notifications from both services are parsed and subscriptions are automatically created when certain event criteria are met; (5) finally, SARVIEWS-generated hazard products are now

  7. On the Implementation of a Land Cover Classification System for SAR Images Using Khoros

    NASA Technical Reports Server (NTRS)

    Medina Revera, Edwin J.; Espinosa, Ramon Vasquez

    1997-01-01

    The Synthetic Aperture Radar (SAR) sensor is widely used to record data about the ground under all atmospheric conditions. The SAR acquired images have very good resolution which necessitates the development of a classification system that process the SAR images to extract useful information for different applications. In this work, a complete system for the land cover classification was designed and programmed using the Khoros, a data flow visual language environment, taking full advantages of the polymorphic data services that it provides. Image analysis was applied to SAR images to improve and automate the processes of recognition and classification of the different regions like mountains and lakes. Both unsupervised and supervised classification utilities were used. The unsupervised classification routines included the use of several Classification/Clustering algorithms like the K-means, ISO2, Weighted Minimum Distance, and the Localized Receptive Field (LRF) training/classifier. Different texture analysis approaches such as Invariant Moments, Fractal Dimension and Second Order statistics were implemented for supervised classification of the images. The results and conclusions for SAR image classification using the various unsupervised and supervised procedures are presented based on their accuracy and performance.

  8. 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.

  9. Ionospheric Specifications for SAR Interferometry (ISSI)

    NASA Technical Reports Server (NTRS)

    Pi, Xiaoqing; Chapman, Bruce D; Freeman, Anthony; Szeliga, Walter; Buckley, Sean M.; Rosen, Paul A.; Lavalle, Marco

    2013-01-01

    The ISSI software package is designed to image the ionosphere from space by calibrating and processing polarimetric synthetic aperture radar (PolSAR) data collected from low Earth orbit satellites. Signals transmitted and received by a PolSAR are subject to the Faraday rotation effect as they traverse the magnetized ionosphere. The ISSI algorithms combine the horizontally and vertically polarized (with respect to the radar system) SAR signals to estimate Faraday rotation and ionospheric total electron content (TEC) with spatial resolutions of sub-kilometers to kilometers, and to derive radar system calibration parameters. The ISSI software package has been designed and developed to integrate the algorithms, process PolSAR data, and image as well as visualize the ionospheric measurements. A number of tests have been conducted using ISSI with PolSAR data collected from various latitude regions using the phase array-type L-band synthetic aperture radar (PALSAR) onboard Japan Aerospace Exploration Agency's Advanced Land Observing Satellite mission, and also with Global Positioning System data. These tests have demonstrated and validated SAR-derived ionospheric images and data correction algorithms.

  10. Digital Intermediate Frequency Receiver Module For Use In Airborne Sar Applications

    DOEpatents

    Tise, Bertice L.; Dubbert, Dale F.

    2005-03-08

    A digital IF receiver (DRX) module directly compatible with advanced radar systems such as synthetic aperture radar (SAR) systems. The DRX can combine a 1 G-Sample/sec 8-bit ADC with high-speed digital signal processor, such as high gate-count FPGA technology or ASICs to realize a wideband IF receiver. DSP operations implemented in the DRX can include quadrature demodulation and multi-rate, variable-bandwidth IF filtering. Pulse-to-pulse (Doppler domain) filtering can also be implemented in the form of a presummer (accumulator) and an azimuth prefilter. An out of band noise source can be employed to provide a dither signal to the ADC, and later be removed by digital signal processing. Both the range and Doppler domain filtering operations can be implemented using a unique pane architecture which allows on-the-fly selection of the filter decimation factor, and hence, the filter bandwidth. The DRX module can include a standard VME-64 interface for control, status, and programming. An interface can provide phase history data to the real-time image formation processors. A third front-panel data port (FPDP) interface can send wide bandwidth, raw phase histories to a real-time phase history recorder for ground processing.

  11. Real time SAR processing

    NASA Technical Reports Server (NTRS)

    Premkumar, A. B.; Purviance, J. E.

    1990-01-01

    A simplified model for the SAR imaging problem is presented. The model is based on the geometry of the SAR system. Using this model an expression for the entire phase history of the received SAR signal is formulated. From the phase history, it is shown that the range and the azimuth coordinates for a point target image can be obtained by processing the phase information during the intrapulse and interpulse periods respectively. An architecture for a VLSI implementation for the SAR signal processor is presented which generates images in real time. The architecture uses a small number of chips, a new correlation processor, and an efficient azimuth correlation process.

  12. Sea bottom topography imaging with SAR

    NASA Technical Reports Server (NTRS)

    Vanderkooij, M. W. A.; Wensink, G. J.; Vogelzang, J.

    1992-01-01

    It is well known that under favorable meteorological and hydrodynamical conditions the bottom topography of shallow seas can be mapped with airborne or spaceborne imaging radar. This phenomenon was observed for the first time in 1969 by de Loor and co-workers in Q-band Side Looking Airborne Radar (SLAR) imagery of sandwaves in the North Sea. It is now generally accepted that the imaging mechanism consists of three steps: (1) interaction between (tidal) current and bottom topography causes spatial modulations in the surface current velocity; (2) modulations in the surface current velocity give rise to variations in the spectrum of wind-generated waves, as described by the action balance equation; and (3) variations in the wave spectrum show up as intensity modulations in radar imagery. In order to predict radar backscatter modulations caused by sandwaves, an imaging model, covering the three steps, was developed by the Dutch Sea Bottom Topography Group. This model and some model results will be shown. On 16 Aug. 1989 an experiment was performed with the polarimetric P-, L-, and C-band synthetic aperture radar (SAR) of NASA/JPL. One scene was recorded in SAR mode. On 12 Jul. 1991 another three scenes were recorded, of which one was in the ATI-mode (Along-Track Interferometer). These experiments took place in the test area of the Sea Bottom Topography Group, 30 km off the Dutch coast, where the bottom topography is dominated by sand waves. In-situ data were gathered by a ship in the test area and on 'Measuring Platform Noordwijk', 20 km from the center of the test area. The radar images made during the experiment were compared with digitized maps of the bottom. Furthermore, the profiles of radar backscatter modulation were compared with the results of the model. During the workshop some preliminary results of the ATI measurements will be shown.

  13. The relationship among sea surface roughness variations, oceanographic analyses, and airborne remote sensing analyses

    NASA Technical Reports Server (NTRS)

    Oertel, G. F.; Wade, T. L.

    1981-01-01

    The synthetic aperture radar (SAR) was studied to determine whether it could image large scale estuaries and oceanic features such as fronts and to explain the electromagnetic interaction between SAR and the individual surface front features. Fronts were observed to occur at the entrance to the Chesapeake Bay. The airborne measurements consisted of data collection by SAR onboard an F-4 aircraft and real aperture side looking radar (SLAR) in Mohawk aircraft. A total of 89 transects were flown. Surface roughness and color as well as temperature and salinity were evaluated. Cross-frontal surveys were made. Frontal shear and convergence flow were obtained. Surface active organic materials, it was indicated, are present at the air-sea interface. In all, 2000 analyses were conducted to characterize the spatial and temporal variabilities associated with water mass boundaries.

  14. Integrated Airborne and In-Situ Measurements Over Land-Fast Ice Near Barrow, AK.

    NASA Astrophysics Data System (ADS)

    Gardner, J. M.; Brozena, J. M.; Richter-Menge, J.; Abelev, A.; Liang, R.; Ball, D.; Claffey, K. J.; Hebert, D. A.; Jones, K.

    2015-12-01

    The Naval Research Laboratory has collected two field seasons of integrated airborne and in-situ measurements over multiple sites of floating, but land-fast ice north of Barrow, AK. During the first season in March of 2014 the Cold Regions Research and Engineering Laboratory led the on-ice group including NRL personnel and Naval Academy midshipmen. The second season (March 2015) included only NRL scientists and midshipmen. The in-situ data provided ground-truth for airborne measurements from a scanning LiDAR (Riegl Q 560i), digital photogrammetry (Applanix DSS-439), a low-frequency SAR (P-band in 2014 and P and L bands in 2015) and a snow/Ku radar procured from the Center for Remote Sensing of Ice Sheets of the University of Kansas. The CReSIS radar was updated in 2015 to integrate the snow and Ku radars into a single continuous chirp, thus improving resolution. The objective of the survey was to aid our understanding of the use of the airborne data to calibrate/validate Cryosat-2 data. Sampling size or "footprint" plays a critical role in the attempt to compare in-situ measurements with airborne (or satellite) measurements. Thus the in-situ data were arranged to minimize aliasing. Ground measurements were collected along transects a sites generally consisting of a 2 km long profile of Magnaprobe and EM31 measurements with periodic boreholes. A 60 m x 400 m swath of Magnaprobe measurements was centered on this profile. Airborne data were collected on multiple overflights of the transect areas. The LiDAR measured total freeboard (ice + snow) referenced to leads in the ice, and produced swaths 200-300 m wide. The SAR imaged the ice beneath the snow and the snow/Ku radar measured snow thickness. The freeboard measurements and snow thickness are used to estimate ice thickness via isostasy and density estimates. Comparisons and processing methodology will be shown. The results of this ground-truth experiment will inform our analysis of grids of airborne data collected

  15. The Impact of Conflicting Spatial Representations in Airborne Unmanned Aerial System Sensor Control

    DTIC Science & Technology

    2016-02-01

    Spatial Discordance 1 Running head: SPATIAL DISCORDANCE IN AIRBORNE UAS OPERATIONS The impact of conflicting spatial...representations in airborne unmanned aerial system sensor control Joseph W Geeseman, James E Patrey, Caroline Davy, Katherine Peditto, & Christine Zernickow...system (UAS) simulation while riding in the fuselage of an airborne Lockheed P-3 Orion. The P-3 flew a flight profile of intermittent ascending

  16. On Ambiguities in SAR Design

    NASA Technical Reports Server (NTRS)

    Freeman, Anthony

    2006-01-01

    Ambiguities are an aliasing effect caused by the periodic sampling of the scene backscatter inherent to pulsed radar systems such as Synthetic Aperture radar (SAR). In this paper we take a fresh look at the relationship between SAR range and azimuth ambiguity constraints on the allowable pulse repetition frequency (PRF) and the antenna length. We show that for high squint angles smaller antennas may be feasible in some cases. For some applications, the ability to form a synthetic aperture at high squint angles is desirable, but the size of the antenna causes problems in the design of systems capable of such operation. This is because the SAR system design is optimized for a side-looking geometry. In two examples design examples we take a suboptimum antenna size and examine the performance in terms of azimuth resolution and swath width as a function of squint angle. We show that for stripmap SARs, the swath width is usually worse for off-boresight squint angles, because it is severely limited by range walk, except in cases where we relax the spatial resolution. We consider the implications for the design of modest-resolution, narrow swath, scanning SAR scatterometers .

  17. 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

  18. Calibration of the Geosar Dual Frequency Interferometric SAR

    NASA Technical Reports Server (NTRS)

    Chapine, Elaine

    1999-01-01

    GeoSAR is an airborne, interferometric Synthetic Aperture Radar (INSAR) system for terrain mapping, currently under development by a consortium including NASA's Jet Propulsion Laboratory (JPL), Calgis, Inc., and the California Department of Conservation (CalDOC) with funding provided by the Topographic Engineering Center (TEC) of the U.S. Army Corps of Engineers and the Defense Advanced Research Projects Agency (DARPA). The radar simultaneously maps swaths on both sides of the aircraft at two frequencies, X-Band and P-Band. For the P-Band system, data is collected for two across track interferometric baselines and at the crossed polarization. The aircraft position and attitude are measured using two Honeywell Embedded GPS Inertial Navigation Units (EGI) and an Ashtech Z12 GPS receiver. The mechanical orientation and position of the antennas are actively measured using a Laser Baseline Metrology System (LBMS). In the GeoSAR motion measurement software, these data are optimally combined with data from a nearby ground station using Ashtech PNAV software to produce the position, orientation, and baseline information are used to process the dual frequency radar data. Proper calibration of the GeoSAR system is essential to obtaining digital elevation models (DEMS) with the required sub-meter level planimetric and vertical accuracies. Calibration begins with the determination of the yaw and pitch biases for the two EGI units. Common range delays are determined for each mode, along with differential time and phase delays between channels. Because the antennas are measured by the LBMS, baseline calibration consists primarily of measuring a constant offset between mechanical center and the electrical phase center of the antennas. A phase screen, an offset to the interferometric phase difference which is a function of absolute phase, is applied to the interferometric data to compensate for multipath and leakage. Calibration parameters are calculated for each of the ten

  19. Local SAR in Parallel Transmission Pulse Design

    PubMed Central

    Lee, Joonsung; Gebhardt, Matthias; Wald, Lawrence L.; Adalsteinsson, Elfar

    2011-01-01

    The management of local and global power deposition in human subjects (Specific Absorption Rate, SAR) is a fundamental constraint to the application of parallel transmission (pTx) systems. Even though the pTx and single channel have to meet the same SAR requirements, the complex behavior of the spatial distribution of local SAR for transmission arrays poses problems that are not encountered in conventional single-channel systems and places additional requirements on pTx RF pulse design. We propose a pTx pulse design method which builds on recent work to capture the spatial distribution of local SAR in numerical tissue models in a compressed parameterization in order to incorporate local SAR constraints within computation times that accommodate pTx pulse design during an in vivo MRI scan. Additionally, the algorithm yields a Protocol-specific Ultimate Peak in Local SAR (PUPiL SAR), which is shown to bound the achievable peak local SAR for a given excitation profile fidelity. The performance of the approach was demonstrated using a numerical human head model and a 7T eight-channel transmit array. The method reduced peak local 10g SAR by 14–66% for slice-selective pTx excitations and 2D selective pTx excitations compared to a pTx pulse design constrained only by global SAR. The primary tradeoff incurred for reducing peak local SAR was an increase in global SAR, up to 34% for the evaluated examples, which is favorable in cases where local SAR constraints dominate the pulse applications. PMID:22083594

  20. Alaska SAR Facility mass storage, current system

    NASA Technical Reports Server (NTRS)

    Cuddy, David; Chu, Eugene; Bicknell, Tom

    1993-01-01

    This paper examines the mass storage systems that are currently in place at the Alaska SAR Facility (SAF). The architecture of the facility will be presented including specifications of the mass storage media that are currently used and the performances that we have realized from the various media. The distribution formats and media are also discussed. Because the facility is expected to service future sensors, the new requirements and possible solutions to these requirements are also discussed.

  1. Terrain Measurement with SAR/InSAR

    NASA Astrophysics Data System (ADS)

    Li, Deren; Liao, Mingsheng; Balz, Timo; Zhang, Lu; Yang, Tianliang

    2016-08-01

    Terrain measurement and surface motion estimation are the most important applications for commercial and scientific SAR missions. In Dragon-3, we worked on these applications, especially regarding DEM generation, surface motion estimation with SAR time- series for urban subsidence monitoring and landslide motion estimation, as well as developing tomographic SAR processing methods in urban areas.

  2. State of the art satellite and airborne marine oil spill remote sensing: Application to the BP Deepwater Horizon oil spill

    USGS Publications Warehouse

    Leifer, Ira; Lehr, William J.; Simecek-Beatty, Debra; Bradley, Eliza; Clark, Roger N.; Dennison, Philip E.; Hu, Yongxiang; Matheson, Scott; Jones, Cathleen E; Holt, Benjamin; Reif, Molly; Roberts, Dar A.; Svejkovsky, Jan; Swayze, Gregg A.; Wozencraft, Jennifer M.

    2012-01-01

    The vast and persistent Deepwater Horizon (DWH) spill challenged response capabilities, which required accurate, quantitative oil assessment at synoptic and operational scales. Although experienced observers are a spill response's mainstay, few trained observers and confounding factors including weather, oil emulsification, and scene illumination geometry present challenges. DWH spill and impact monitoring was aided by extensive airborne and spaceborne passive and active remote sensing.Oil slick thickness and oil-to-water emulsion ratios are key spill response parameters for containment/cleanup and were derived quantitatively for thick (> 0.1 mm) slicks from AVIRIS (Airborne Visible/Infrared Imaging Spectrometer) data using a spectral library approach based on the shape and depth of near infrared spectral absorption features. MODIS (Moderate Resolution Imaging Spectroradiometer) satellite, visible-spectrum broadband data of surface-slick modulation of sunglint reflection allowed extrapolation to the total slick. A multispectral expert system used a neural network approach to provide Rapid Response thickness class maps.Airborne and satellite synthetic aperture radar (SAR) provides synoptic data under all-sky conditions; however, SAR generally cannot discriminate thick (> 100 μm) oil slicks from thin sheens (to 0.1 μm). The UAVSAR's (Uninhabited Aerial Vehicle SAR) significantly greater signal-to-noise ratio and finer spatial resolution allowed successful pattern discrimination related to a combination of oil slick thickness, fractional surface coverage, and emulsification.In situ burning and smoke plumes were studied with AVIRIS and corroborated spaceborne CALIPSO (Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observation) observations of combustion aerosols. CALIPSO and bathymetry lidar data documented shallow subsurface oil, although ancillary data were required for confirmation.Airborne hyperspectral, thermal infrared data have nighttime and

  3. Low-SAR metamaterial-inspired printed monopole antenna

    NASA Astrophysics Data System (ADS)

    Hossain, M. I.; Faruque, M. R. I.; Islam, M. T.; Ali, M. T.

    2017-01-01

    In this paper, a low-SAR metamaterial-embedded planar monopole antenna is introduced for a wireless communication system. A printed monopole antenna is designed for modern mobile, which operates in GSM, UMTS, LTE, WLAN, and Bluetooth frequency bands. A metamaterial structure is designed to use in the mobile handset with a multi-band printed monopole antenna. The finite integration technique of the CST microwave studio is used in this study. The measurement of antenna performances is taken in an anechoic chamber, and the SAR values are measured using COMOSAR system. The results indicate that metamaterial structure leads to reduce SAR without affecting antenna performance significantly. According to the measured results, the metamaterial attachment leads to reduce 87.7% peak SAR, 68.2% 1-g SAR, and 46.78% 10-g SAR compared to antenna without metamaterial.

  4. Spaceborne SAR Data for Aboveground-Biomass Retrieval of Indian Tropical Forests

    NASA Astrophysics Data System (ADS)

    Khati, U.; Singh, G.; Musthafa, M.

    2017-12-01

    Forests are important and indispensable part of the terrestrial ecosystems, and have a direct impact on the global carbon cycle. Forest biophysical parameters such as forest stand height and forest above-ground biomass (AGB) are forest health indicators. Measuring the forest biomass using traditional ground survey techniques are man-power consuming and have very low spatial coverage. Satellite based remote sensing techniques provide synoptic view of the earth with continuous measurements over large, inaccessible forest regions. Satellite Synthetic Aperture Radar (SAR) data has been shown to be sensitive to these forest bio-physical parameters and have been extensively utilized over boreal and tropical forests. However, there are limited studies over Indian tropical forests due to lack of auxiliary airborne data and difficulties in manual in situ data collection. In this research work we utilize spaceborne data from TerraSAR-X/TanDEM-X and ALOS-2/PALSAR-2 and implement both Polarimetric SAR and PolInSAR techniques for retrieval of AGB of a managed tropical forest in India. The TerraSAR-X/TanDEM-X provide a single-baseline PolInSAR data robust to temporal decorrelation. This would be used to accurately estimate the forest stand height. The retrieved height would be an input parameter for modelling AGB using the L-band ALOS-2/PALSAR-2 data. The IWCM model is extensively utilized to estimate AGB from SAR observations. In this research we utilize the six component scattering power decomposition (6SD) parameters and modify the IWCM based technique for a better retrieval of forest AGB. PolInSAR data shows a high estimation accuracy with r2 of 0.8 and a RMSE of 2 m. With this accurate height provided as input to the modified model along with 6SD parameters shows promising results. The results are validated with extensive field based measurements, and are further analysed in detail.

  5. An evaluation of selected (Q)SARs/expert systems for the Prediction of Skin Sensitization Potential (WC10)

    EPA Science Inventory

    One of the alternative approaches to assessing skin sensitization hazard is through the use of (Q)SARs/expert systems. Here we evaluate the predictive performance of two expert systems (TIMES-SS and VEGA) and two SAR rulebases (OASIS protein binding alerts and Toxtree’s reactivit...

  6. Comparison of JPL-AIRSAR and DLR E-SAR images from the MAC Europe 1991 campaign over testsite Oberpfaffenhofen: Frequency and polarization dependent backscatter variations from agricultural fields

    NASA Technical Reports Server (NTRS)

    Schmullius, C.; Nithack, J.

    1992-01-01

    On July 12, the MAC Europe '91 (Multi-Sensor Airborne Campaign) took place over test site Oberpfaffenhofen. The DLR Institute of Radio-Frequency Technology participated with its C-VV, X-VV, and X-HH Experimental Synthetic Aperture Radar (E-SAR). The high resolution E-SAR images with a pixel size between 1 and 2 m and the polarimetric AIRSAR images were analyzed. Using both sensors in combination is a unique opportunity to evaluate SAR images in a frequency range from P- to X-band and to investigate polarimetric information.

  7. Research on the error model of airborne celestial/inertial integrated navigation system

    NASA Astrophysics Data System (ADS)

    Zheng, Xiaoqiang; Deng, Xiaoguo; Yang, Xiaoxu; Dong, Qiang

    2015-02-01

    Celestial navigation subsystem of airborne celestial/inertial integrated navigation system periodically correct the positioning error and heading drift of the inertial navigation system, by which the inertial navigation system can greatly improve the accuracy of long-endurance navigation. Thus the navigation accuracy of airborne celestial navigation subsystem directly decides the accuracy of the integrated navigation system if it works for long time. By building the mathematical model of the airborne celestial navigation system based on the inertial navigation system, using the method of linear coordinate transformation, we establish the error transfer equation for the positioning algorithm of airborne celestial system. Based on these we built the positioning error model of the celestial navigation. And then, based on the positioning error model we analyze and simulate the positioning error which are caused by the error of the star tracking platform with the MATLAB software. Finally, the positioning error model is verified by the information of the star obtained from the optical measurement device in range and the device whose location are known. The analysis and simulation results show that the level accuracy and north accuracy of tracking platform are important factors that limit airborne celestial navigation systems to improve the positioning accuracy, and the positioning error have an approximate linear relationship with the level error and north error of tracking platform. The error of the verification results are in 1000m, which shows that the model is correct.

  8. Local SAR in parallel transmission pulse design.

    PubMed

    Lee, Joonsung; Gebhardt, Matthias; Wald, Lawrence L; Adalsteinsson, Elfar

    2012-06-01

    The management of local and global power deposition in human subjects (specific absorption rate, SAR) is a fundamental constraint to the application of parallel transmission (pTx) systems. Even though the pTx and single channel have to meet the same SAR requirements, the complex behavior of the spatial distribution of local SAR for transmission arrays poses problems that are not encountered in conventional single-channel systems and places additional requirements on pTx radio frequency pulse design. We propose a pTx pulse design method which builds on recent work to capture the spatial distribution of local SAR in numerical tissue models in a compressed parameterization in order to incorporate local SAR constraints within computation times that accommodate pTx pulse design during an in vivo magnetic resonance imaging scan. Additionally, the algorithm yields a protocol-specific ultimate peak in local SAR, which is shown to bound the achievable peak local SAR for a given excitation profile fidelity. The performance of the approach was demonstrated using a numerical human head model and a 7 Tesla eight-channel transmit array. The method reduced peak local 10 g SAR by 14-66% for slice-selective pTx excitations and 2D selective pTx excitations compared to a pTx pulse design constrained only by global SAR. The primary tradeoff incurred for reducing peak local SAR was an increase in global SAR, up to 34% for the evaluated examples, which is favorable in cases where local SAR constraints dominate the pulse applications. Copyright © 2011 Wiley Periodicals, Inc.

  9. The lessons of SARS.

    PubMed

    Emanuel, Ezekiel J

    2003-10-07

    Given the low mortality and morbidity of the severe acute respiratory syndrome (SARS) compared with other public health scourges, is the attention devoted to it misdirected? The SARS experience has provided at least 4 enduring lessons. First, by providing a test of the capacity of each part of the public health system, from national to local and hospital responses, it has better prepared the world for the anticipated and much-feared next real pandemic. Second, SARS has reemphasized that from housing, sexual practices, and slaughtering techniques to health care capacity, the situation in other, especially developing, countries affects us. Global cooperation is necessary not only for justice but to ensure our own health. Third, despite trends toward commercialization, easier lives, and self-centered individualism, the response of health care professionals to SARS reaffirmed dedication to caring for the sick even at great personal risks as the core ethical principle of medicine. Finally, SARS also emphasized the importance of the duty of health care administrators and senior physicians to rapidly institute procedures to maximize the safety of frontline physicians and nurses. These lessons will be valuable far beyond the SARS episode.

  10. New observations of Bolivian wind streaks by JPL Airborne SAR: Preliminary results

    NASA Technical Reports Server (NTRS)

    Blumberg, Dan G.; Greeley, Ronald

    1995-01-01

    In 1993 NASA's Jet Propulsion Laboratory Airborne Synthetic Aperture Radar system (AIRSAR) was deployed to South America to collect multi-parameter radar data over pre-selected targets. Among the sites targeted was a series of wind streaks located in the Altiplano of Bolivia. The objective of this investigation is to study the effect of wavelength, polarization, and incidence angle on the visibility of wind streaks in radar data. Because this is a preliminary evaluation of the recently acquired data we will focus on one scene and, thus, only on the effects of wavelength and polarization. Wind streaks provide information on the near-surface prevailing winds and on the abundance of winderodible material, such as sand. The potential for a free-flyer radar system that could provide global radar images in multiple wavelengths, polarizations, and incidence angles requires definition of system parameters for mission planning. Furthermore, thousands of wind streaks were mapped from Magellan radar images of Venus; their interpretation requires an understanding of the interaction of radar with wind streaks and the surrounding terrain. Our experiment was conducted on wind streaks in the Altiplano of Bolivia to address these issues.

  11. Estimation of bare soil evaporation using multifrequency airborne SAR

    NASA Technical Reports Server (NTRS)

    Soares, Joao V.; Shi, Jiancheng; Van Zyl, Jakob; Engman, E. T.

    1992-01-01

    It is shown that for homogeneous areas soil moisture can be derived from synthetic aperture radar (SAR) measurements, so that the use of microwave remote sensing can given realistic estimates of energy fluxes if coupled to a simple two-layer model repesenting the soil. The model simulates volumetric water content (Wg) using classical meterological data, provided that some of the soil thermal and hydraulic properties are known. Only four parameters are necessary: mean water content, thermal conductivity and diffusitivity, and soil resistance to evaporation. They may be derived if a minimal number of measured values of Wg and surface layer temperature (Tg) are available together with independent measurements of energy flux to compare with the estimated values. The estimated evaporation is shown to be realistic and in good agreement with drying stage theory in which the transfer of water in the soil is in vapor form.

  12. The geophysical processor system: Automated analysis of ERS-1 SAR imagery

    NASA Technical Reports Server (NTRS)

    Stern, Harry L.; Rothrock, D. Andrew; Kwok, Ronald; Holt, Benjamin

    1994-01-01

    The Geophysical Processor System (GPS) at the Alaska (U.S.) SAR (Synthetic Aperture Radar) Facility (ASF) uses ERS-1 SAR images as input to generate three types of products: sea ice motion, sea ice type, and ocean wave spectra. The GPS, operating automatically with minimal human intervention, delivers its output to the Archive and Catalog System (ACS) where scientists can search and order the products on line. The GPS has generated more than 10,000 products since it became operational in Feb. 1992, and continues to deliver 500 new products per month to the ACS. These products cover the Beaufort and Chukchi Seas and the western portion of the central Arctic Ocean. More geophysical processing systems are needed to handle the large volumes of data from current and future satellites. Images must be routinely and consistently analyzed to yield useful information for scientists. The current GPS is a good, working prototype on the way to more sophisticated systems.

  13. Geocoding of AIRSAR/TOPSAR SAR Data

    NASA Technical Reports Server (NTRS)

    Holecz, Francesco; Lou, Yun-Ling; vanZyl, Jakob

    1996-01-01

    It has been demonstrated and recognized that radar interferometry is a promising method for the determination of digital elevation information and terrain slope from Synthetic Aperture Radar (SAR) data. An important application of Interferometric SAR (InSAR) data in areas with topographic variations is that the derived elevation and slope can be directly used for the absolute radiometric calibration of the amplitude SAR data as well as for scattering mechanisms analysis. On the other hand polarimetric SAR data has long been recognized as permitting a more complete inference of natural surfaces than a single channel radar system. In fact, imaging polarimetry provides the measurement of the amplitude and relative phase of all transmit and receive polarizations. On board the NASA DC-8 aircraft, NASA/JPL operates the multifrequency (P, L and C bands) multipolarimetric radar AIRSAR. The TOPSAR, a special mode of the AIRSAR system, is able to collect single-pass interferometric C- and/or L-band VV polarized data. A possible configuration of the AIRSAR/TOPSAR system is to acquire single-pass interferometric data at C-band VV polarization and polarimetric radar data at the two other lower frequencies. The advantage of this system configuration is to get digital topography information at the same time the radar data is collected. The digital elevation information can therefore be used to correctly calibrate the SAR data. This step is directly included in the new AIRSAR Integrated Processor. This processor uses a modification of the full motion compensation algorithm described by Madsen et al. (1993). However, the Digital Elevation Model (DEM) with the additional products such as local incidence angle map, and the SAR data are in a geometry which is not convenient, since especially DEMs must be referred to a specific cartographic reference system. Furthermore, geocoding of SAR data is important for multisensor and/or multitemporal purposes. In this paper, a procedure to

  14. Integration of TerraSAR-X, RapidEye and airborne lidar for remote sensing of intertidal bedforms on the upper flats of Norderney (German Wadden Sea)

    NASA Astrophysics Data System (ADS)

    Adolph, Winny; Jung, Richard; Schmidt, Alena; Ehlers, Manfred; Heipke, Christian; Bartholomä, Alexander; Farke, Hubert

    2017-04-01

    The Wadden Sea is a large coastal transition area adjoining the southern North Sea uniting ecological key functions with an important role in coastal protection. The region is strictly protected by EU directives and national law and is a UNESCO World Heritage Site, requiring frequent quality assessments and regular monitoring. In 2014 an intertidal bedform area characterised by alternating crests and water-covered troughs on the tidal flats of the island of Norderney (German Wadden Sea sector) was chosen to test different remote sensing methods for habitat mapping: airborne lidar, satellite-based radar (TerraSAR-X) and electro-optical sensors (RapidEye). The results revealed that, although sensitive to different surface qualities, all sensors were able to image the bedforms. A digital terrain model generated from the lidar data shows crests and slopes of the bedforms with high geometric accuracy in the centimetre range, but high costs limit the operation area. TerraSAR-X data enabled identifying the positions of the bedforms reflecting the residual water in the troughs also with a high resolution of up to 1.1 m, but with larger footprints and much higher temporal availability. RapidEye data are sensitive to differences in sediment moisture employed to identify crest areas, slopes and troughs, with high spatial coverage but the lowest resolution (6.5 m). Monitoring concepts may differ in their remote sensing requirements regarding areal coverage, spatial and temporal resolution, sensitivity and geometric accuracy. Also financial budgets limit the selection of sensors. Thus, combining differing assets into an integrated concept of remote sensing contributes to solving these issues.

  15. Prevention the spread of norovirus infection on airborne route by using Plasma Assisted Catalytic Technology (PACT) device.

    PubMed

    Tanaka, Yoshimoto; Fujino, Kan; Larkins, Gerald Andrew; Osawa, Atsushi; Hayashi, Yuji; Taharaguchi, Satoshi

    2018-04-30

    Zoonosis becomes a popular word. Highly pathogenic influenza virus (HPI), Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS) recently occurred at around Africa, Meddle-East and South-East Asia area, whose virus is classified as airborne. Sterilization capability was investigated by using chemical reactor of PACT device. Test on airborne infection was carried out by Feline Calicivirus Vaccine (FCV) strain F9, which is also surrogated human norovirus. It was found that PACT device could sterilize instantly FCV when passing through the plasma space of PACT device. Sterilization rate may be more than 99.99% (below the detection limit). This result may be available to sterilize various virus including human norovirus and airborne-infectious microorganisms.

  16. The Arctic Boreal Vulnerability Experiment (ABoVE) 2017 Airborne Campaign

    NASA Astrophysics Data System (ADS)

    Miller, C. E.; Goetz, S. J.; Griffith, P. C.; Hoy, E.; Larson, E. K.; Hodkinson, D. J.; Hansen, C.; Woods, J.; Kasischke, E. S.; Margolis, H. A.

    2017-12-01

    The 2017 ABoVE Airborne Campaign (AAC) was one of the largest airborne experiments ever conducted by NASA's Earth Science Division. It involved nine aircraft in 17 deployments - more than 100 flights - between April and October and sampled over 4 million km2in Alaska and northwestern Canada. Many of these flights were coordinated with detailed, same-day ground-based measurements to link field-based, process-level studies with geospatial data products derived from satellite remote sensing. A major goal of the 2017 AAC was to collect data that spanned the critical intermediate space and time scales that are essential for a comprehensive understanding of scaling issues across the ABoVE Study Domain and extrapolation to the pan-Arctic. Additionally, the 2017 AAC provided unique opportunities to validate satellite and airborne remote sensing data for northern high latitude ecosystems, develop and advance fundamental remote sensing science, and explore scientific insights from innovative sensor combinations. The 2017 AAC science strategy coupled domain-wide sampling with L-band and P-band synthetic aperture radar (SAR), imaging spectroscopy (AVIRIS-NG), full waveform lidar (LVIS) and atmospheric carbon dioxide and methane with more spatially and temporally focused studies using Ka-band SAR (Ka-SPAR) and solar induced chlorophyll fluorescence (CFIS). Additional measurements were coordinated with the NEON Airborne Observing Platform, the ASCENDS instrument development suite, and the ATOM EV-S2 investigation. Targets of interest included the array of field sites operated by the ABoVE Science Team as well as the intensive sites operated by the DOE NGEE-Arctic team on the Seward Peninsula and in Barrow, NSF's LTER sites at Toolik Lake (North Slope) and Bonanza Creek (Interior Alaska), the Canadian Cold Regions Hydrology sites in the Arctic tundra near Trail Valley Creek NT, the Government of the Northwest Territories Slave River/Slave Delta watershed time series and numerous

  17. Airborne water vapor DIAL research: System development and field measurements

    NASA Technical Reports Server (NTRS)

    Higdon, Noah S.; Browell, Edward V.; Ponsardin, Patrick; Chyba, Thomas H.; Grossmann, Benoist E.; Butler, Carolyn F.; Fenn, Marta A.; Mayor, Shane D.; Ismail, Syed; Grant, William B.

    1992-01-01

    This paper describes the airborne differential absorption lidar (DIAL) system developed at the NASA Langley Research Center for remote measurement of water vapor (H2O) and aerosols in the lower atmosphere. The airborne H2O DIAL system was flight tested aboard the NASA Wallops Flight Facility (WFF) Electra aircraft in three separate field deployments between 1989 and 1991. Atmospheric measurements were made under a variety of atmospheric conditions during the flight tests, and several modifications were implemented during this development period to improve system operation. A brief description of the system and major modifications will be presented, and the most significant atmospheric observations will be described.

  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. 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.

  20. 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.

  1. InSAR time series analysis of ALOS-2 ScanSAR data and its implications for NISAR

    NASA Astrophysics Data System (ADS)

    Liang, C.; Liu, Z.; Fielding, E. J.; Huang, M. H.; Burgmann, R.

    2017-12-01

    planned for NISAR, which implies that a good coregistration strategy for NISAR's SweepSAR mode is geometrical coregistration followed by MAI or spectral diversity analysis. Besides, our development also provides implications for the processing and system parameter requirements of NISAR, such as the accuracy requirement of azimuth FM rate and range timing.

  2. 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.

  3. Final Report (O1-ERD-051) Dynamic InSAR: Imaging Seismic Waves Remotely from Space

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

    Vincent, P; Rodgers, A; Dodge, D

    2003-02-07

    The purpose of this LDRD project was to determine the feasibility of using InSAR (interferometric synthetic aperture radar) to image seismic waves remotely from space. If shown to be feasible, the long-term goal of this project would be to influence future SAR satellite missions and airborne SAR platforms to include a this new capability. This final report summarizes the accomplishments of the originally-planned 2-year project that was cut short to 1 year plus 2 months due to a funding priority change that occurred in the aftermath of the September 11th tragedy. The LDRD-ER project ''Dynamic InSAR: Imaging Seismic Waves frommore » Space'' (01-ERD-051) began in October, (FY01) and ended in December (FY02). Consequently, most of the results and conclusions for this project are represented in the FY0l Annual Report. Nonetheless, additional conclusions and insights regarding the progress of this work are included in this report. In should be noted that this work was restarted and received additional funding under the NA-22 DOE Nonproliferation Program in FY03.« less

  4. SAR image registration based on Susan algorithm

    NASA Astrophysics Data System (ADS)

    Wang, Chun-bo; Fu, Shao-hua; Wei, Zhong-yi

    2011-10-01

    Synthetic Aperture Radar (SAR) is an active remote sensing system which can be installed on aircraft, satellite and other carriers with the advantages of all day and night and all-weather ability. It is the important problem that how to deal with SAR and extract information reasonably and efficiently. Particularly SAR image geometric correction is the bottleneck to impede the application of SAR. In this paper we introduces image registration and the Susan algorithm knowledge firstly, then introduces the process of SAR image registration based on Susan algorithm and finally presents experimental results of SAR image registration. The Experiment shows that this method is effective and applicable, no matter from calculating the time or from the calculation accuracy.

  5. Hardware Design for a Fixed-Wing Airborne Gravity Measurement System

    DTIC Science & Technology

    1986-12-22

    worldwide navigation system currently available that is sufficiently accurate for deter- mining Eotvos correction in airborne gravimetry is the Global...better in defining the strength of precipitation . The radar display is compact enough to be mounted on the cockpit, thus giving the pilots better...of the proposed AGMS version 3 MISCELLANEOUS AIRCRAFT CONSIDERATIONS Autopilot One of the most important considerations in airborne gravimetry is

  6. High Resolution Digital Surface Model For Production Of Airport Obstruction Charts Using Spaceborne SAR Sensors

    NASA Astrophysics Data System (ADS)

    Oliveira, Henrique; Rodrigues, Marco; Radius, Andrea

    2012-01-01

    Airport Obstruction Charts (AOCs) are graphical representations of natural or man-made obstructions (its locations and heights) around airfields, according to International Civil Aviation Organization (ICAO) Annexes 4, 14 and 15. One of the most important types of data used in AOCs production/update tasks is a Digital Surface Model (first reflective surface) of the surveyed area. The development of advanced remote sensing technologies provide the available tools for obstruction data acquisition, while Geographic Information Systems (GIS) present the perfect platform for storing and analyzing this type of data, enabling the production of digital ACOs, greatly contributing to the increase of the situational awareness of pilots and enhancing the air navigation safety level [1]. Data acquisition corresponding to the first reflective surface can be obtained through the use of Airborne Laser-Scanning and Light Detection and Ranging (ALS/LIDAR) or Spaceborne SAR Systems. The need of surveying broad areas, like the entire territory of a state, shows that Spaceborne SAR systems are the most adequate in economic and feasibility terms of the process, to perform the monitoring and producing a high resolution Digital Surface Model (DSM). The high resolution DSM generation depends on many factors: the available data set, the used technique and the setting parameters. To increase the precision and obtain high resolution products, two techniques are available using a stack of data: the PS (Permanent Scatterers) technique [2], that uses large stack of data to identify many stable and coherent targets through multi- temporal analysis, removing the atmospheric contribution and to minimize the estimation errors, and the Small Baseline Subset (SBAS) technique ([3],[4]), that relies on the use of small baseline SAR interferograms and on the application of the so called singular value decomposition (SVD) method, in order to link independent SAR acquisition data sets, separated by large

  7. Web-GIS-based SARS epidemic situation visualization

    NASA Astrophysics Data System (ADS)

    Lu, Xiaolin

    2004-03-01

    In order to research, perform statistical analysis and broadcast the information of SARS epidemic situation according to the relevant spatial position, this paper proposed a unified global visualization information platform for SARS epidemic situation based on Web-GIS and scientific virtualization technology. To setup the unified global visual information platform, the architecture of Web-GIS based interoperable information system is adopted to enable public report SARS virus information to health cure center visually by using the web visualization technology. A GIS java applet is used to visualize the relationship between spatial graphical data and virus distribution, and other web based graphics figures such as curves, bars, maps and multi-dimensional figures are used to visualize the relationship between SARS virus tendency with time, patient number or locations. The platform is designed to display the SARS information in real time, simulate visually for real epidemic situation and offer an analyzing tools for health department and the policy-making government department to support the decision-making for preventing against the SARS epidemic virus. It could be used to analyze the virus condition through visualized graphics interface, isolate the areas of virus source, and control the virus condition within shortest time. It could be applied to the visualization field of SARS preventing systems for SARS information broadcasting, data management, statistical analysis, and decision supporting.

  8. The Staphylococcus aureus protein-coding gene gdpS modulates sarS expression via mRNA-mRNA interaction.

    PubMed

    Chen, Chuan; Zhang, Xu; Shang, Fei; Sun, Haipeng; Sun, Baolin; Xue, Ting

    2015-08-01

    Staphylococcus aureus is an important Gram-positive pathogen responsible for numerous diseases ranging from localized skin infections to life-threatening systemic infections. The virulence of S. aureus is essentially determined by a wide spectrum of factors, including cell wall-associated proteins and secreted toxins that are precisely controlled in response to environmental changes. GGDEF domain protein from Staphylococcus (GdpS) is the only conserved staphylococcal GGDEF domain protein that is involved not in c-di-GMP synthesis but in the virulence regulation of S. aureus NCTC8325. Our previous study showed that the inactivation of gdpS generates an extensive change of virulence factors together with, in particular, a major Spa (protein A) surface protein. As reported, sarS is a direct positive regulator of spa. The decreased transcript levels of sarS in the gdpS mutant compared with the parental NCTC8325 strain suggest that gdpS affects spa through interaction with sarS. In this study, site mutation and complementary experiments showed that the translation product of gdpS was not involved in the regulation of transcript levels of sarS. We found that gdpS functioned through direct RNA-RNA base pairing with the 5' untranslated region (5'UTR) of sarS mRNA and that a putative 18-nucleotide region played a significant role in the regulatory process. Furthermore, the mRNA half-life analysis of sarS in the gdpS mutant showed that gdpS positively regulates the mRNA levels of sarS by contributing to the stabilization of sarS mRNA, suggesting that gdpS mRNA may regulate spa expression in an RNA-dependent pathway. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  9. 3D Tomographic SAR Imaging in Densely Vegetated Mountainous Rural Areas in China and Sweden

    NASA Astrophysics Data System (ADS)

    Feng, L.; Muller, J. P., , Prof

    2017-12-01

    3D SAR Tomography (TomoSAR) and 4D SAR Differential Tomography (Diff-TomoSAR) exploit multi-baseline SAR data stacks to create an important new innovation of SAR Interferometry, to unscramble complex scenes with multiple scatterers mapped into the same SAR cell. In addition to this 3-D shape reconstruction and deformation solution in complex urban/infrastructure areas, and recent cryospheric ice investigations, emerging tomographic remote sensing applications include forest applications, e.g. tree height and biomass estimation, sub-canopy topographic mapping, and even search, rescue and surveillance. However, these scenes are characterized by temporal decorrelation of scatterers, orbital, tropospheric and ionospheric phase distortion and an open issue regarding possible height blurring and accuracy losses for TomoSAR applications particularly in densely vegetated mountainous rural areas. Thus, it is important to develop solutions for temporal decorrelation, orbital, tropospheric and ionospheric phase distortion.We report here on 3D imaging (especially in vertical layers) over densely vegetated mountainous rural areas using 3-D SAR imaging (SAR tomography) derived from data stacks of X-band COSMO-SkyMed Spotlight and L band ALOS-1 PALSAR data stacks over Dujiangyan Dam, Sichuan, China and L and P band airborne SAR data (BioSAR 2008 - ESA) in the Krycklan river catchment, Northern Sweden. The new TanDEM-X 12m DEM is used to assist co - registration of all the data stacks over China first. Then, atmospheric correction is being assessed using weather model data such as ERA-I, MERRA, MERRA-2, WRF; linear phase-topography correction and MODIS spectrometer correction will be compared and ionospheric correction methods are discussed to remove tropospheric and ionospheric delay. Then the new TomoSAR method with the TanDEM-X 12m DEM is described to obtain the number of scatterers inside each pixel, the scattering amplitude and phase of each scatterer and finally extract

  10. Aircraft Detection in High-Resolution SAR Images Based on a Gradient Textural Saliency Map.

    PubMed

    Tan, Yihua; Li, Qingyun; Li, Yansheng; Tian, Jinwen

    2015-09-11

    This paper proposes a new automatic and adaptive aircraft target detection algorithm in high-resolution synthetic aperture radar (SAR) images of airport. The proposed method is based on gradient textural saliency map under the contextual cues of apron area. Firstly, the candidate regions with the possible existence of airport are detected from the apron area. Secondly, directional local gradient distribution detector is used to obtain a gradient textural saliency map in the favor of the candidate regions. In addition, the final targets will be detected by segmenting the saliency map using CFAR-type algorithm. The real high-resolution airborne SAR image data is used to verify the proposed algorithm. The results demonstrate that this algorithm can detect aircraft targets quickly and accurately, and decrease the false alarm rate.

  11. Aircraft Detection in High-Resolution SAR Images Based on a Gradient Textural Saliency Map

    PubMed Central

    Tan, Yihua; Li, Qingyun; Li, Yansheng; Tian, Jinwen

    2015-01-01

    This paper proposes a new automatic and adaptive aircraft target detection algorithm in high-resolution synthetic aperture radar (SAR) images of airport. The proposed method is based on gradient textural saliency map under the contextual cues of apron area. Firstly, the candidate regions with the possible existence of airport are detected from the apron area. Secondly, directional local gradient distribution detector is used to obtain a gradient textural saliency map in the favor of the candidate regions. In addition, the final targets will be detected by segmenting the saliency map using CFAR-type algorithm. The real high-resolution airborne SAR image data is used to verify the proposed algorithm. The results demonstrate that this algorithm can detect aircraft targets quickly and accurately, and decrease the false alarm rate. PMID:26378543

  12. Mathematical modeling and SAR simulation multifunction SAR technology efforts

    NASA Technical Reports Server (NTRS)

    Griffin, C. R.; Estes, J. M.

    1981-01-01

    The orbital SAR (synthetic aperture radar) simulation data was used in several simulation efforts directed toward advanced SAR development. Efforts toward simulating an operational radar, simulation of antenna polarization effects, and simulation of SAR images at serveral different wavelengths are discussed. Avenues for improvements in the orbital SAR simulation and its application to the development of advanced digital radar data processing schemes are indicated.

  13. Comparative Study of Speckle Filtering Methods in PolSAR Radar Images

    NASA Astrophysics Data System (ADS)

    Boutarfa, S.; Bouchemakh, L.; Smara, Y.

    2015-04-01

    Images acquired by polarimetric SAR (PolSAR) radar systems are characterized by the presence of a noise called speckle. This noise has a multiplicative nature, corrupts both the amplitude and phase images, which complicates data interpretation, degrades segmentation performance and reduces the detectability of targets. Hence, the need to preprocess the images by adapted filtering methods before analysis.In this paper, we present a comparative study of implemented methods for reducing speckle in PolSAR images. These developed filters are: refined Lee filter based on the estimation of the minimum mean square error MMSE, improved Sigma filter with detection of strong scatterers based on the calculation of the coherency matrix to detect the different scatterers in order to preserve the polarization signature and maintain structures that are necessary for image interpretation, filtering by stationary wavelet transform SWT using multi-scale edge detection and the technique for improving the wavelet coefficients called SSC (sum of squared coefficients), and Turbo filter which is a combination between two complementary filters the refined Lee filter and the wavelet transform SWT. One filter can boost up the results of the other.The originality of our work is based on the application of these methods to several types of images: amplitude, intensity and complex, from a satellite or an airborne radar, and on the optimization of wavelet filtering by adding a parameter in the calculation of the threshold. This parameter will control the filtering effect and get a good compromise between smoothing homogeneous areas and preserving linear structures.The methods are applied to the fully polarimetric RADARSAT-2 images (HH, HV, VH, VV) acquired on Algiers, Algeria, in C-band and to the three polarimetric E-SAR images (HH, HV, VV) acquired on Oberpfaffenhofen area located in Munich, Germany, in P-band.To evaluate the performance of each filter, we used the following criteria

  14. Airborne data measurement system errors reduction through state estimation and control optimization

    NASA Astrophysics Data System (ADS)

    Sebryakov, G. G.; Muzhichek, S. M.; Pavlov, V. I.; Ermolin, O. V.; Skrinnikov, A. A.

    2018-02-01

    The paper discusses the problem of airborne data measurement system errors reduction through state estimation and control optimization. The approaches are proposed based on the methods of experiment design and the theory of systems with random abrupt structure variation. The paper considers various control criteria as applied to an aircraft data measurement system. The physics of criteria is explained, the mathematical description and the sequence of steps for each criterion application is shown. The formula is given for airborne data measurement system state vector posterior estimation based for systems with structure variations.

  15. Highly Protable Airborne Multispectral Imaging System

    NASA Technical Reports Server (NTRS)

    Lehnemann, Robert; Mcnamee, Todd

    2001-01-01

    A portable instrumentation system is described that includes and airborne and a ground-based subsytem. It can acquire multispectral image data over swaths of terrain ranging in width from about 1.5 to 1 km. The system was developed especially for use in coastal environments and is well suited for performing remote sensing and general environmental monitoring. It includes a small,munpilotaed, remotely controlled airplance that carries a forward-looking camera for navigation, three downward-looking monochrome video cameras for imaging terrain in three spectral bands, a video transmitter, and a Global Positioning System (GPS) reciever.

  16. Study on Landslide Disaster Extraction Method Based on Spaceborne SAR Remote Sensing Images - Take Alos Palsar for AN Example

    NASA Astrophysics Data System (ADS)

    Xue, D.; Yu, X.; Jia, S.; Chen, F.; Li, X.

    2018-04-01

    In this paper, sequence ALOS PALSAR data and airborne SAR data of L-band from June 5, 2008 to September 8, 2015 are used. Based on the research of SAR data preprocessing and core algorithms, such as geocode, registration, filtering, unwrapping and baseline estimation, the improved Goldstein filtering algorithm and the branch-cut path tracking algorithm are used to unwrap the phase. The DEM and surface deformation information of the experimental area were extracted. Combining SAR-specific geometry and differential interferometry, on the basis of composite analysis of multi-source images, a method of detecting landslide disaster combining coherence of SAR image is developed, which makes up for the deficiency of single SAR and optical remote sensing acquisition ability. Especially in bad weather and abnormal climate areas, the speed of disaster emergency and the accuracy of extraction are improved. It is found that the deformation in this area is greatly affected by faults, and there is a tendency of uplift in the southeast plain and western mountainous area, while in the southwest part of the mountain area there is a tendency to sink. This research result provides a basis for decision-making for local disaster prevention and control.

  17. 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

  18. 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.

  19. PacRIM II: A review of AirSAR operations and system performance

    NASA Technical Reports Server (NTRS)

    Moller, D.; Chu, A.; Lou, Y.; Miller, T.; O'Leary, E.

    2001-01-01

    In this paper we briefly review the AirSAR system, its expected performance, and quality of data obtained during that mission. We discuss the system hardware calibration methodologies, and present quantitative performance values of radar backscatter and interferometric height errors (random and systematic) from PACRIM II calibration data.

  20. 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.

  1. Synthetic aperture radar for a crop information system: A multipolarization and multitemporal approach

    NASA Astrophysics Data System (ADS)

    Ban, Yifang

    Acquisition of timely information is a critical requirement for successful management of an agricultural monitoring system. Crop identification and crop-area estimation can be done fairly successfully using satellite sensors operating in the visible and near-infrared (VIR) regions of the spectrum. However, data collection can be unreliable due to problems of cloud cover at critical stages of the growing season. The all-weather capability of synthetic aperture radar (SAR) imagery acquired from satellites provides data over large areas whenever crop information is required. At the same time, SAR is sensitive to surface roughness and should be able to provide surface information such as tillage-system characteristics. With the launch of ERS-1, the first long-duration SAR system became available. The analysis of airborne multipolarization SAR data, multitemporal ERS-1 SAR data, and their combinations with VIR data, is necessary for the development of image-analysis methodologies that can be applied to RADARSAT data for extracting agricultural crop information. The overall objective of this research is to evaluate multipolarization airborne SAR data, multitemporal ERS-1 SAR data, and combinations of ERS-1 SAR and satellite VIR data for crop classification using non-conventional algorithms. The study area is situated in Norwich Township, an agricultural area in Oxford County, southern Ontario, Canada. It has been selected as one of the few representative agricultural 'supersites' across Canada at which the relationships between radar data and agriculture are being studied. The major field crops are corn, soybeans, winter wheat, oats, barley, alfalfa, hay, and pasture. Using airborne C-HH and C-HV SAR data, it was found that approaches using contextual information, texture information and per-field classification for improving agricultural crop classification proved to be effective, especially the per-field classification method. Results show that three of the four best

  2. 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.

  3. A prototype of an automated high resolution InSAR volcano-monitoring system in the MED-SUV project

    NASA Astrophysics Data System (ADS)

    Chowdhury, Tanvir A.; Minet, Christian; Fritz, Thomas

    2016-04-01

    Volcanic processes which produce a variety of geological and hydrological hazards are difficult to predict and capable of triggering natural disasters on regional to global scales. Therefore it is important to monitor volcano continuously and with a high spatial and temporal sampling rate. The monitoring of active volcanoes requires the reliable measurement of surface deformation before, during and after volcanic activities and it helps for the better understanding and modelling of the involved geophysical processes. Space-borne synthetic aperture radar (SAR) interferometry (InSAR), persistent scatterer interferometry (PSI) and small baseline subset algorithm (SBAS) provide a powerful tool for observing the eruptive activities and measuring the surface changes of millimetre accuracy. All the mentioned techniques with deformation time series extraction address the challenges by exploiting medium to large SAR image stacks. The process of selecting, ordering, downloading, storing, logging, extracting and preparing the data for processing is very time consuming has to be done manually for every single data-stack. In many cases it is even an iterative process which has to be done regularly and continuously. Therefore, data processing becomes slow which causes significant delays in data delivery. The SAR Satellite based High Resolution Data Acquisition System, which will be developed at DLR, will automate this entire time consuming tasks and allows an operational volcano monitoring system. Every 24 hours the system runs for searching new acquired scene over the volcanoes and keeps track of the data orders, log the status and download the provided data via ftp-transfer including E-Mail alert. Furthermore, the system will deliver specified reports and maps to a database for review and use by specialists. The user interaction will be minimized and iterative processes will be totally avoided. In this presentation, a prototype of SAR Satellite based High Resolution Data

  4. Hardware Development and Error Characterization for the AFIT RAIL SAR System

    DTIC Science & Technology

    This research is focused on updating the Air Force Institute of Technology (AFIT) Radar Instrumentation Lab (RAIL)Synthetic Aperture Radar ( SAR ...collections from a receiver in motion. Secondly, orthogonal frequency-division multiplexing (OFDM) signals are used to form ( SAR ) images in multiple...experimental and simulation configurations. This research analyses, characterizes and attempts compensation of relevant SAR image error sources, such as Doppler

  5. High Resolution Airborne InSAR DEM of Bagley Ice Valley, South-central Alaska: Geodetic Validation with Airborne Laser Altimeter Data

    NASA Astrophysics Data System (ADS)

    Muskett, R. R.; Lingle, C. S.; Echelmeyer, K. A.; Valentine, V. B.; Elsberg, D.

    2001-12-01

    Bagley Ice Valley, in the St. Elias and Chugach Mountains of south-central Alaska, is an integral part of the largest connected glacierized terrain on the North American continent. From the flow divide between Mt. Logan and Mt. St. Elias, Bagley Ice Valley flows west-northwest for some 90 km down a slope of less than 1o, at widths up to 15 km, to a saddle-gap where it turns south-west to become Bering Glacier. During 4-13 September 2000, an airborne survey of Bagley Ice Valley was performed by Intermap Technologies, Inc., using their Star-3i X-band SAR interferometer. The resulting digital elevation model (DEM) covers an area of 3243 km2. The DEM elevations are orthometric heights, in meters above the EGM96 geoid. The horizontal locations of the 10-m postings are with respect to the WGS84 ellipsoid. On 26 August 2000, 9 to 18 days prior to the Intermap Star-3i survey, a small-aircraft laser altimeter profile was acquired along the central flow line for validation. The laser altimeter data consists of elevations above the WGS84 ellipsoid and orthometric heights above GEOID99-Alaska. Assessment of the accuracy of the Intermap Star-3i DEM was made by comparison of both the DEM orthometric heights and elevations above the WGS84 ellipsoid with the laser altimeter data. Comparison of the orthometric heights showed an average difference of 5.4 +/- 1.0 m (DEM surface higher). Comparison of elevations above the WGS84 ellipsoid showed an average difference of -0.77 +/- 0.93 m (DEM surface lower). This indicates that the X-band Star-3i interferometer was penetrating the glacier surface by an expected small amount. The WGS84 comparison is well within the 3 m RMS accuracy quoted for GT-3 DEM products. Snow accumulation may have occurred, however, on Bagley Ice Valley between 26 August and 4-13 September 2000. This will be estimated using a mass balance model and used to correct the altimeter-derived surface heights. The new DEM of Bagley Ice Valley will provide a reference

  6. Airborne multidimensional integrated remote sensing system

    NASA Astrophysics Data System (ADS)

    Xu, Weiming; Wang, Jianyu; Shu, Rong; He, Zhiping; Ma, Yanhua

    2006-12-01

    In this paper, we present a kind of airborne multidimensional integrated remote sensing system that consists of an imaging spectrometer, a three-line scanner, a laser ranger, a position & orientation subsystem and a stabilizer PAV30. The imaging spectrometer is composed of two sets of identical push-broom high spectral imager with a field of view of 22°, which provides a field of view of 42°. The spectral range of the imaging spectrometer is from 420nm to 900nm, and its spectral resolution is 5nm. The three-line scanner is composed of two pieces of panchromatic CCD and a RGB CCD with 20° stereo angle and 10cm GSD(Ground Sample Distance) with 1000m flying height. The laser ranger can provide height data of three points every other four scanning lines of the spectral imager and those three points are calibrated to match the corresponding pixels of the spectral imager. The post-processing attitude accuracy of POS/AV 510 used as the position & orientation subsystem, which is the aerial special exterior parameters measuring product of Canadian Applanix Corporation, is 0.005° combined with base station data. The airborne multidimensional integrated remote sensing system was implemented successfully, performed the first flying experiment on April, 2005, and obtained satisfying data.

  7. SAR operational aspects

    NASA Astrophysics Data System (ADS)

    Holmdahl, P. E.; Ellis, A. B. E.; Moeller-Olsen, P.; Ringgaard, J. P.

    1981-12-01

    The basic requirements of the SAR ground segment of ERS-1 are discussed. A system configuration for the real time data acquisition station and the processing and archive facility is depicted. The functions of a typical SAR processing unit (SPU) are specified, and inputs required for near real time and full precision, deferred time processing are described. Inputs and the processing required for provision of these inputs to the SPU are dealt with. Data flow through the systems, and normal and nonnormal operational sequence, are outlined. Prerequisites for maintaining overall performance are identified, emphasizing quality control. The most demanding tasks to be performed by the front end are defined in order to determine types of processors and peripherals which comply with throughput requirements.

  8. (abstract) The EOS SAR Mission: A New Approach

    NASA Technical Reports Server (NTRS)

    Way, JoBea

    1993-01-01

    The goal of the Earth Orbiting System Synthetic Aperture Radar (EOS SAR) program is to help develop the modeling and observational capabilities to predict and monitor terrestrial and oceanic processes that are either causing global change or resulting from global change. Specifically, the EOS SAR will provide important geophysical products to the EOS data set to improve our understanding of the state and functioning of the Earth system. The strategy for the EOS SAR program is to define the instrument requirements based on required input to geophysical algorithms, provide the processing capability and algorithms to generate such products on the required spatial (global) and temporal (3-5 days) scales, and to provide the spaceborne instrumentation with international partnerships. Initially this partnership has been with Germany; currently we are exploring broader international partnerships. A MultiSAR approach to the EOS SAR which includes a number of SARs provided by Japan, ESA, Germany, Canada, and the US in synergistic orbits could be used to attain a truly global monitoring capability using multifrequency polarimetric signatures. These concepts and several options for mission scenarios will be presented.

  9. Impact of the Regulators SigB, Rot, SarA and sarS on the Toxic Shock Tst Promoter and TSST-1 Expression in Staphylococcus aureus

    PubMed Central

    Villanueva, Maite; Renzoni, Adriana; Monod, Antoinette; Barras, Christine; Rodriguez, Natalia; Kelley, William L.

    2015-01-01

    Staphylococcus aureus is an important pathogen manifesting virulence through diverse disease forms, ranging from acute skin infections to life-threatening bacteremia or systemic toxic shock syndromes. In the latter case, the prototypical superantigen is TSST-1 (Toxic Shock Syndrome Toxin 1), encoded by tst(H), and carried on a mobile genetic element that is not present in all S. aureus strains. Transcriptional regulation of tst is only partially understood. In this study, we dissected the role of sarA, sarS (sarH1), RNAIII, rot, and the alternative stress sigma factor sigB (σB). By examining tst promoter regulation predominantly in the context of its native sequence within the SaPI1 pathogenicity island of strain RN4282, we discovered that σB emerged as a particularly important tst regulator. We did not detect a consensus σB site within the tst promoter, and thus the effect of σB is likely indirect. We found that σB strongly repressed the expression of the toxin via at least two distinct regulatory pathways dependent upon sarA and agr. Furthermore rot, a member of SarA family, was shown to repress tst expression when overexpressed, although its deletion had no consistent measurable effect. We could not find any detectable effect of sarS, either by deletion or overexpression, suggesting that this regulator plays a minimal role in TSST-1 expression except when combined with disruption of sarA. Collectively, our results extend our understanding of complex multifactorial regulation of tst, revealing several layers of negative regulation. In addition to environmental stimuli thought to impact TSST-1 production, these findings support a model whereby sporadic mutation in a few key negative regulators can profoundly affect and enhance TSST-1 expression. PMID:26275216

  10. Satellite on-board real-time SAR processor prototype

    NASA Astrophysics Data System (ADS)

    Bergeron, Alain; Doucet, Michel; Harnisch, Bernd; Suess, Martin; Marchese, Linda; Bourqui, Pascal; Desnoyers, Nicholas; Legros, Mathieu; Guillot, Ludovic; Mercier, Luc; Châteauneuf, François

    2017-11-01

    A Compact Real-Time Optronic SAR Processor has been successfully developed and tested up to a Technology Readiness Level of 4 (TRL4), the breadboard validation in a laboratory environment. SAR, or Synthetic Aperture Radar, is an active system allowing day and night imaging independent of the cloud coverage of the planet. The SAR raw data is a set of complex data for range and azimuth, which cannot be compressed. Specifically, for planetary missions and unmanned aerial vehicle (UAV) systems with limited communication data rates this is a clear disadvantage. SAR images are typically processed electronically applying dedicated Fourier transformations. This, however, can also be performed optically in real-time. Originally the first SAR images were optically processed. The optical Fourier processor architecture provides inherent parallel computing capabilities allowing real-time SAR data processing and thus the ability for compression and strongly reduced communication bandwidth requirements for the satellite. SAR signal return data are in general complex data. Both amplitude and phase must be combined optically in the SAR processor for each range and azimuth pixel. Amplitude and phase are generated by dedicated spatial light modulators and superimposed by an optical relay set-up. The spatial light modulators display the full complex raw data information over a two-dimensional format, one for the azimuth and one for the range. Since the entire signal history is displayed at once, the processor operates in parallel yielding real-time performances, i.e. without resulting bottleneck. Processing of both azimuth and range information is performed in a single pass. This paper focuses on the onboard capabilities of the compact optical SAR processor prototype that allows in-orbit processing of SAR images. Examples of processed ENVISAT ASAR images are presented. Various SAR processor parameters such as processing capabilities, image quality (point target analysis), weight and

  11. Multichannel High Resolution Wide Swath SAR Imaging for Hypersonic Air Vehicle with Curved Trajectory.

    PubMed

    Zhou, Rui; Sun, Jinping; Hu, Yuxin; Qi, Yaolong

    2018-01-31

    Synthetic aperture radar (SAR) equipped on the hypersonic air vehicle in near space has many advantages over the conventional airborne SAR. However, its high-speed maneuvering characteristics with curved trajectory result in serious range migration, and exacerbate the contradiction between the high resolution and wide swath. To solve this problem, this paper establishes the imaging geometrical model matched with the flight trajectory of the hypersonic platform and the multichannel azimuth sampling model based on the displaced phase center antenna (DPCA) technology. Furthermore, based on the multichannel signal reconstruction theory, a more efficient spectrum reconstruction model using discrete Fourier transform is proposed to obtain the azimuth uniform sampling data. Due to the high complexity of the slant range model, it is difficult to deduce the processing algorithm for SAR imaging. Thus, an approximate range model is derived based on the minimax criterion, and the optimal second-order approximate coefficients of cosine function are obtained using the two-population coevolutionary algorithm. On this basis, aiming at the problem that the traditional Omega-K algorithm cannot compensate the residual phase with the difficulty of Stolt mapping along the range frequency axis, this paper proposes an Exact Transfer Function (ETF) algorithm for SAR imaging, and presents a method of range division to achieve wide swath imaging. Simulation results verify the effectiveness of the ETF imaging algorithm.

  12. Multichannel High Resolution Wide Swath SAR Imaging for Hypersonic Air Vehicle with Curved Trajectory

    PubMed Central

    Zhou, Rui; Hu, Yuxin; Qi, Yaolong

    2018-01-01

    Synthetic aperture radar (SAR) equipped on the hypersonic air vehicle in near space has many advantages over the conventional airborne SAR. However, its high-speed maneuvering characteristics with curved trajectory result in serious range migration, and exacerbate the contradiction between the high resolution and wide swath. To solve this problem, this paper establishes the imaging geometrical model matched with the flight trajectory of the hypersonic platform and the multichannel azimuth sampling model based on the displaced phase center antenna (DPCA) technology. Furthermore, based on the multichannel signal reconstruction theory, a more efficient spectrum reconstruction model using discrete Fourier transform is proposed to obtain the azimuth uniform sampling data. Due to the high complexity of the slant range model, it is difficult to deduce the processing algorithm for SAR imaging. Thus, an approximate range model is derived based on the minimax criterion, and the optimal second-order approximate coefficients of cosine function are obtained using the two-population coevolutionary algorithm. On this basis, aiming at the problem that the traditional Omega-K algorithm cannot compensate the residual phase with the difficulty of Stolt mapping along the range frequency axis, this paper proposes an Exact Transfer Function (ETF) algorithm for SAR imaging, and presents a method of range division to achieve wide swath imaging. Simulation results verify the effectiveness of the ETF imaging algorithm. PMID:29385059

  13. Corner reflector SAR interferometry as an element of a landslide early warning system

    NASA Astrophysics Data System (ADS)

    Singer, J.; Riedmann, M.; Lang, O.; Anderssohn, J.; Thuro, K.; Wunderlich, Th.; Heunecke, O.; Minet, Ch.

    2012-04-01

    The development of efficient and cost-effective landslide monitoring techniques is the central aim of the alpEWAS research project (www.alpewas.de). Within the scope of the project a terrestrial geosensor network on a landslide site in the Bavarian Alps has been set up, consisting of low cost GNSS with subcentimeter precision, time domain reflectometry (TDR) and video tacheometry (VTPS). To increase the spatial sampling, 16 low-cost Radar Corner Reflectors (CRs) were installed on the site in 2011. The CRs are to reflect radar signals back to the TerraSAR-X radar satellite, allowing for precise displacement measurements. The subject of this study is the application of the CR SAR Interferometry (CRInSAR) technique, and the integration of the derived motion field into an early warning system for landslide monitoring based on terrestrial measurements. An accurate validation data set is realized independently of the monitoring network using millimeter precision GNSS and tacheometer measurements. The 12 CRs from Astrium Geo-Information Services employed over the test site were specifically designed for TerraSAR-X satellite passes. They are made of concrete with integrated metal plates weighing about 80 to 100 kg. They are of triangular trihedral shape with minimal dimensions to obtain a Radar Cross Section 100 times stronger than that of the surrounding area. The concrete guarantees stability against harsh weather conditions, and robustness with respect to vandalism or theft. In addition, the Technical University of Munich (TUM) and the German Aerospace Center (DLR) installed another four CRs made entirely out of aluminum, with the TUM reflectors being of similar minimum size than the Astrium reflectors. Three CRs were placed on assumed stable ground outside the slope area and shall act as reference reflectors. Since the installation date of most CRs (25/08/2011), TerraSAR-X HighResolution SpotLight data have been repeatedly acquired from ascending orbit over the test

  14. Beacon Collision Avoidance System (BCAS) Airborne Antenna Diversity Study

    DOT National Transportation Integrated Search

    1978-04-01

    The potential need for antenna diversity on the intruding aircraft was examined. The BCAS system was used for determining airborne antenna diversity requirements for general aviation aircraft approaching a BCAS equipped aircraft from various angles. ...

  15. Lack of SARS transmission and U.S. SARS case-patient.

    PubMed

    Peck, Angela J; Newbern, E Claire; Feikin, Daniel R; Issakbaeva, Elmira T; Park, Benjamin J; Fehr, Jason; LaMonte, Ashley C; Le, Thong P; Burger, Terry L; Rhodes, Luther V; Weltman, Andre; Erdman, Dean; Ksiazek, Thomas G; Lingappa, Jairam R

    2004-02-01

    In early April 2003, severe acute respiratory syndrome (SARS) was diagnosed in a Pennsylvania resident after his exposure to persons with SARS in Toronto, Canada. To identify contacts of the case-patient and evaluate the risk for SARS transmission, a detailed epidemiologic investigation was performed. On the basis of this investigation, 26 persons (17 healthcare workers, 4 household contacts, and 5 others) were identified as having had close contact with this case-patient before infection-control practices were implemented. Laboratory evaluation of clinical specimens showed no evidence of transmission of SARS-associated coronavirus (SARS-CoV) infection to any close contact of this patient. This investigation documents that, under certain circumstances, SARS-CoV is not readily transmitted to close contacts, despite ample unprotected exposures. Improving the understanding of risk factors for transmission will help focus public health control measures.

  16. SAR studies in the Yuma Desert, Arizona: Sand penetration, geology, and the detection of military ordnance debris

    USGS Publications Warehouse

    Schaber, G.G.

    1999-01-01

    Synthetic Aperture Radar (SAR) images acquired over part of the Yuma Desert in southwestern Arizona demonstrate the ability of C-band (5.7-cm wavelength), L-band (24.5 cm), and P-band (68 cm) AIRSAR signals to backscatter from increasingly greater depths reaching several meters in blow sand and sandy alluvium. AIRSAR images obtained within the Barry M. Goldwater Bombing and Gunnery Range near Yuma, Arizona, show a total reversal of C- and P-band backscatter contrast (image tone) for three distinct geologic units. This phenomenon results from an increasingly greater depth of radar imaging with increasing radar wavelength. In the case of sandy- and small pebble-alluvium surfaces mantled by up to several meters of blow sand, backscatter increases directly with SAR wavelength as a result of volume scattering from a calcic soil horizon at shallow depth and by volume scattering from the root mounds of healthy desert vegetation that locally stabilize blow sand. AIRSAR images obtained within the military range are also shown to be useful for detecting metallic military ordnance debris that is located either at the surface or covered by tens of centimeters to several meters of blow sand. The degree of detectability of this ordnance increases with SAR wavelength and is clearly maximized on P-band images that are processed in the cross-polarized mode (HV). This effect is attributed to maximum signal penetration at P-band and the enhanced PHV image contrast between the radar-bright ordnance debris and the radar-dark sandy desert. This article focuses on the interpretation of high resolution AIRSAR images but also Compares these airborne SAR images with those acquired from spacecraft sensors such as ERS-SAR and Space Radar Laboratory (SIR-C/X-SAR).Synthetic Aperture Radar (SAR) images acquired over part of the Yuma Desert in southwestern Arizona demonstrate the ability of C-band (5.7-cm wavelength), L-band (24.5 cm), and P-band (68 cm) AIRSAR signals to backscatter from

  17. Indoor Unmanned Airship System Airborne Control Module Design

    NASA Astrophysics Data System (ADS)

    YongXia, Gao; YiBo, Li

    By adopting STC12C5A60S2 SCM as a system control unit, assisted by appropriate software and hardware resources, we complete the airborne control module's design of unmanned airship system. This paper introduces hardware control module's structure, airship-driven composition and software realization. Verified by the China Science and Technology Museum special-shaped airship,this control module can work well.

  18. NASA/JPL Aircraft SAR Workshop Proceedings

    NASA Technical Reports Server (NTRS)

    Donovan, N. (Editor); Evans, D. L. (Editor); Held, D. N. (Editor)

    1985-01-01

    Speaker-supplied summaries of the talks given at the NASA/JPL Aircraft SAR Workshop on February 4 and 5, 1985, are provided. These talks dealt mostly with composite quadpolarization imagery from a geologic or ecologic prespective. An overview and summary of the system characteristics of the L-band synthetic aperture radar (SAR) flown on the NASA CV-990 aircraft are included as supplementary information. Other topics ranging from phase imagery and interferometric techniques classifications of specific areas, and the potentials and limitations of SAR imagery in various applications are discussed.

  19. Primary studies of Chinese spaceborne SAR

    NASA Technical Reports Server (NTRS)

    Wang, Zhen-Song; Wu, Guo-Xiang; Guo, Hua-Dong; Wei, Zhong-Quan; Zhu, Min-Hui

    1993-01-01

    The primary studies on spaceborne synthetic aperture radar (SAR) in China are discussed. The SAR will be launched aboard a Chinese satellite and operated at L-band with HH polarization. The purpose of the mission in consideration is dedicated to resources and environment uses, especially to natural disaster monitoring. The ground resolution is designed as 25 m x 25 m for detailed mode and 100 m x 100 m for wide scan-SAR mode. The off-nadir angle can be varied from 20 to 40 deg. The key system concepts are introduced.

  20. Improved Absolute Radiometric Calibration of a UHF Airborne Radar

    NASA Technical Reports Server (NTRS)

    Chapin, Elaine; Hawkins, Brian P.; Harcke, Leif; Hensley, Scott; Lou, Yunling; Michel, Thierry R.; Moreira, Laila; Muellerschoen, Ronald J.; Shimada, Joanne G.; Tham, Kean W.; hide

    2015-01-01

    The AirMOSS airborne SAR operates at UHF and produces fully polarimetric imagery. The AirMOSS radar data are used to produce Root Zone Soil Moisture (RZSM) depth profiles. The absolute radiometric accuracy of the imagery, ideally of better than 0.5 dB, is key to retrieving RZSM, especially in wet soils where the backscatter as a function of soil moisture function tends to flatten out. In this paper we assess the absolute radiometric uncertainty in previously delivered data, describe a method to utilize Built In Test (BIT) data to improve the radiometric calibration, and evaluate the improvement from applying the method.

  1. A joint method to retrieve directional ocean wave spectra from SAR and wave spectrometer data

    NASA Astrophysics Data System (ADS)

    Ren, Lin; Yang, Jingsong; Zheng, Gang; Wang, Juan

    2016-07-01

    This paper proposes a joint method to simultaneously retrieve wave spectra at different scales from spaceborne Synthetic Aperture Radar (SAR) and wave spectrometer data. The method combines the output from the two different sensors to overcome retrieval limitations that occur in some sea states. The wave spectrometer sensitivity coefficient is estimated using an effective significant wave height (SWH), which is an average of SAR-derived and wave spectrometer-derived SWH. This averaging extends the area of the sea surface sampled by the nadir beam of the wave spectrometer to improve the accuracy of the estimated sensitivity coefficient in inhomogeneous sea states. Wave spectra are then retrieved from SAR data using wave spectrometer-derived spectra as first guess spectra to complement the short waves lost in SAR data retrieval. In addition, the problem of 180° ambiguity in retrieved spectra is overcome using SAR imaginary cross spectra. Simulated data were used to validate the joint method. The simulations demonstrated that retrieved wave parameters, including SWH, peak wave length (PWL), and peak wave direction (PWD), agree well with reference parameters. Collocated data from ENVISAT advanced SAR (ASAR), the airborne wave spectrometer STORM, the PHAROS buoy, and the European Centre for Medium-Range Weather Forecasting (ECMWF) were then used to verify the proposed method. Wave parameters retrieved from STORM and two ASAR images were compared to buoy and ECMWF wave data. Most of the retrieved parameters were comparable to reference parameters. The results of this study show that the proposed joint retrieval method could be a valuable complement to traditional methods used to retrieve directional ocean wave spectra, particularly in inhomogeneous sea states.

  2. Extraction of Coastlines with Fuzzy Approach Using SENTINEL-1 SAR Image

    NASA Astrophysics Data System (ADS)

    Demir, N.; Kaynarca, M.; Oy, S.

    2016-06-01

    Coastlines are important features for water resources, sea products, energy resources etc. Coastlines are changed dynamically, thus automated methods are necessary for analysing and detecting the changes along the coastlines. In this study, Sentinel-1 C band SAR image has been used to extract the coastline with fuzzy logic approach. The used SAR image has VH polarisation and 10x10m. spatial resolution, covers 57 sqkm area from the south-east of Puerto-Rico. Additionally, radiometric calibration is applied to reduce atmospheric and orbit error, and speckle filter is used to reduce the noise. Then the image is terrain-corrected using SRTM digital surface model. Classification of SAR image is a challenging task since SAR and optical sensors have very different properties. Even between different bands of the SAR sensors, the images look very different. So, the classification of SAR image is difficult with the traditional unsupervised methods. In this study, a fuzzy approach has been applied to distinguish the coastal pixels than the land surface pixels. The standard deviation and the mean, median values are calculated to use as parameters in fuzzy approach. The Mean-standard-deviation (MS) Large membership function is used because the large amounts of land and ocean pixels dominate the SAR image with large mean and standard deviation values. The pixel values are multiplied with 1000 to easify the calculations. The mean is calculated as 23 and the standard deviation is calculated as 12 for the whole image. The multiplier parameters are selected as a: 0.58, b: 0.05 to maximize the land surface membership. The result is evaluated using airborne LIDAR data, only for the areas where LIDAR dataset is available and secondly manually digitized coastline. The laser points which are below 0,5 m are classified as the ocean points. The 3D alpha-shapes algorithm is used to detect the coastline points from LIDAR data. Minimum distances are calculated between the LIDAR points of

  3. Crustal Deformation along San Andreas Fault System revealed by GPS and Sentinel-1 InSAR

    NASA Astrophysics Data System (ADS)

    Xu, X.; Sandwell, D. T.

    2017-12-01

    We present a crustal deformation velocity map along the San Andreas Fault System by combining measurements from Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) velocity models (CGM V1). We assembled 5 tracks of descending Sentinel-1 InSAR data spanning 2014.11-2017.02, and produced 545 interferograms, each of which covers roughly 250km x 420km area ( 60 bursts). These interferograms are unwrapped using SNAPHU [Chen & Zebker, 2002], with the 2Npi unwrapping ambiguity corrected with a sparse recovery method. We used coherence-based small baseline subset (SBAS) method [Tong & Schmidt, 2016] together with atmospheric correction by common-point stacking [Tymofyeyeva and Fialko, 2015] to construct deformation time series [Xu et. al., 2017]. Then we project the horizontal GPS model and vertical GPS data into satellite line-of-sight directions separately. We first remove the horizontal GPS model from InSAR measurements and perform elevation-dependent atmospheric phase correction. Then we compute the discrepancy between the remaining InSAR measurements and vertical GPS data. We interpolate this discrepancy and remove it from the residual InSAR measurements. Finally, we restore the horizontal GPS model. Preliminary results show that fault creep over the San Jacinto fault, the Elsinore fault, and the San Andreas creeping section is clearly resolved. During the period of drought, the Central Valley of California was subsiding at a high rate (up to 40 cm/yr), while the city of San Jose is uplifting due to recharge, with a quaternary fault acting as a ground water barrier. These findings will be reported during the meeting.

  4. Estimating forest structural characteristics using the airborne LiDAR scanning system and a near-real time profiling laser system

    NASA Astrophysics Data System (ADS)

    Zhao, Kaiguang

    LiDAR (Light Detection and Ranging) directly measures canopy vertical structures, and provides an effective remote sensing solution to accurate and spatially-explicit mapping of forest characteristics, such as canopy height and Leaf Area Index. However, many factors, such as large data volume and high costs for data acquisition, precludes the operational and practical use of most currently available LiDARs for frequent and large-scale mapping. At the same time, a growing need is arising for real-time remote sensing platforms, e.g., to provide timely information for urgent applications. This study aims to develop an airborne profiling LiDAR system, featured with on-the-fly data processing, for near real- or real-time forest inventory. The development of such a system involves implementing the on-board data processing and analysis as well as building useful regression-based models to relate LiDAR measurements with forest biophysical parameters. This work established a paradigm for an on-the-fly airborne profiling LiDAR system to inventory regional forest resources in real- or near real-time. The system was developed based on an existing portable airborne laser system (PALS) that has been previously assembled at NASA by Dr. Ross Nelson. Key issues in automating PALS as an on-the-fly system were addressed, including the design of an archetype for the system workflow, the development of efficient and robust algorithms for automatic data processing and analysis, the development of effective regression models to predict forest biophysical parameters from LiDAR measurements, and the implementation of an integrated software package to incorporate all the above development. This work exploited the untouched potential of airborne laser profilers for real-time forest inventory, and therefore, documented an initial step toward developing airborne-laser-based, on-the-fly, real-time, forest inventory systems. Results from this work demonstrated the utility and effectiveness of

  5. TerraSAR-X InSAR multipass analysis on Venice, Italy)

    NASA Astrophysics Data System (ADS)

    Nitti, D. O.; Nutricato, R.; Bovenga, F.; Refice, A.; Chiaradia, M. T.; Guerriero, L.

    2009-09-01

    The TerraSAR-X (copyright) mission, launched in 2007, carries a new X-band Synthetic Aperture Radar (SAR) sensor optimally suited for SAR interferometry (InSAR), thus allowing very promising application of InSAR techniques for the risk assessment on areas with hydrogeological instability and especially for multi-temporal analysis, such as Persistent Scatterer Interferometry (PSI) techniques, originally developed at Politecnico di Milano. The SPINUA (Stable Point INterferometry over Unurbanised Areas) technique is a PSI processing methodology which has originally been developed with the aim of detection and monitoring of coherent PS targets in non or scarcely-urbanized areas. The main goal of the present work is to describe successful applications of the SPINUA PSI technique in processing X-band data. Venice has been selected as test site since it is in favorable settings for PSI investigations (urban area containing many potential coherent targets such as buildings) and in view of the availability of a long temporal series of TerraSAR-X stripmap acquisitions (27 scenes in all). The Venice Lagoon is affected by land sinking phenomena, whose origins are both natural and man-induced. The subsidence of Venice has been intensively studied for decades by determining land displacements through traditional monitoring techniques (leveling and GPS) and, recently, by processing stacks of ERS/ENVISAT SAR data. The present work is focused on an independent assessment of application of PSI techniques to TerraSAR-X stripmap data for monitoring the stability of the Venice area. Thanks to its orbital repeat cycle of only 11 days, less than a third of ERS/ENVISAT C-band missions, the maximum displacement rate that can be unambiguously detected along the Line-of-Sight (LOS) with TerraSAR-X SAR data through PSI techniques is expected to be about twice the corresponding value of ESA C-band missions, being directly proportional to the sensor wavelength and inversely proportional to the

  6. Generation and assessment of turntable SAR data for the support of ATR development

    NASA Astrophysics Data System (ADS)

    Cohen, Marvin N.; Showman, Gregory A.; Sangston, K. James; Sylvester, Vincent B.; Gostin, Lamar; Scheer, C. Ruby

    1998-10-01

    Inverse synthetic aperture radar (ISAR) imaging on a turntable-tower test range permits convenient generation of high resolution two-dimensional images of radar targets under controlled conditions for testing SAR image processing and for supporting automatic target recognition (ATR) algorithm development. However, turntable ISAR images are often obtained under near-field geometries and hence may suffer geometric distortions not present in airborne SAR images. In this paper, turntable data collected at Georgia Tech's Electromagnetic Test Facility are used to begin to assess the utility of two- dimensional ISAR imaging algorithms in forming images to support ATR development. The imaging algorithms considered include a simple 2D discrete Fourier transform (DFT), a 2-D DFT with geometric correction based on image domain resampling, and a computationally-intensive geometric matched filter solution. Images formed with the various algorithms are used to develop ATR templates, which are then compared with an eye toward utilization in an ATR algorithm.

  7. 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.

  8. 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.

  9. On the use of L-band multipolarization airborne SAR for surveys of crops, vineyards, and orchards in a California irrigated agricultural region

    NASA Technical Reports Server (NTRS)

    Paris, J. F.

    1985-01-01

    The airborne L-band synthetic aperture radar (SAR) collected multipolarization calibrated image data over an irrigated agricultural test site near Fresno, CA, on March 6, 1984. The conclusions of the study are as follows: (1) the effects of incidence angle on the measured backscattering coefficients could be removed by using a correction factor equal to the secant of the angle raised to the 1.4 power, (2) for this scene and time of year, the various polarization channels were highly correlated such that the use of more than one polarization added little to the ability of the radar to discriminate vegetation type or condition; the exception was barley which separated from vineyards only when a combination of like and cross polarization data were used (polarization was very useful for corn identification in fall crops), (3) an excellent separation between herbaceous vegetation (alfalfa, barley, and oats) or bare fields and trees in orchards existed in brightness was well correlated to alfalfa height or biomass, especially for the HH polarization combination, (5) vineyards exhibited a narrow range of brightnesses with no systematic effects of type or number of stakes nor of number of wires in the trellises nor of the size of the vines, (6) within the orchard classes, areal biomass characterized by basal area differences caused radar image brightness differences for small to medium trees but not for medium to large trees.

  10. 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.

  11. Airborne Cloud Computing Environment (ACCE)

    NASA Technical Reports Server (NTRS)

    Hardman, Sean; Freeborn, Dana; Crichton, Dan; Law, Emily; Kay-Im, Liz

    2011-01-01

    Airborne Cloud Computing Environment (ACCE) is JPL's internal investment to improve the return on airborne missions. Improve development performance of the data system. Improve return on the captured science data. The investment is to develop a common science data system capability for airborne instruments that 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.

  12. Forest Structure Retrieval From EcoSAR P-Band Single-Pass Interferometry

    NASA Technical Reports Server (NTRS)

    Osmanoglu, Batuhan; Rincon, Rafael; Lee, Seung Kuk; Fatoyinbo, Temilola; Bollian, Tobias

    2017-01-01

    EcoSAR is a single-pass (dual antenna) digital beamforming, P-band radar system that is designed for remote sensing of dense forest structure. Forest structure retrievals require the measurement related to the vertical dimension, for which several techniques have been developed over the years. These techniques use polarimetric and interferometric aspects of the SAR data, which can be collected using EcoSAR. In this paper we describe EcoSAR system in light of its interferometric capabilities and investigate forest structure retrieval techniques.

  13. The planned Alaska SAR Facility - An overview

    NASA Technical Reports Server (NTRS)

    Carsey, Frank; Weeks, Wilford

    1987-01-01

    The Alaska SAR Facility (ASF) is described in an overview fashion. The facility consists of three major components, a Receiving Ground System, a SAR Processing System and an Analysis and Archiving System; the ASF Program also has a Science Working Team and the requisite management and operations systems. The ASF is now an approved and fully funded activity; detailed requirements and science background are presented for the facility to be implemented for data from the European ERS-1, the Japanese ERS-1 and Radarsat.

  14. 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.

  15. Space-borne polarimetric SAR sensors or the golden age of radar polarimetry

    NASA Astrophysics Data System (ADS)

    Pottier, E.

    2010-06-01

    SAR Polarimetry represents an active area of research in Active Earth Remote Sensing. This interest is clearly supported by the fact that nowadays there exists, or there will exist in a very next future, a non negligible quantity of launched Polarimetric SAR Spaceborne sensors. The ENVISAT satellite, developed by ESA, was launched on March 2002, and was the first Spaceborne sensor offering an innovative dualpolarization Advanced Synthetic Aperture Radar (ASAR) system operating at C-band. The second Polarimetric Spaceborne sensor is ALOS, a Japanese Earth-Observation satellite, developed by JAXA and was launched in January 2006. This mission includes an active L-band polarimetric radar sensor (PALSAR) whose highresolution data may be used for environmental and hazard monitoring. The third Polarimetric Spaceborne sensor is TerraSAR-X, a new German radar satellite, developed by DLR, EADS-Astrium and Infoterra GmbH, was launched on June 2007. This sensor carries a dual-polarimetric and high frequency X-Band SAR sensor that can be operated in different modes and offers features that were not available from space before. At least, the Polarimetric Spaceborne sensor, developed by CSA and MDA, and named RADARSAT-2 was launched in December 2007 The Radarsat program was born out the need for effective monitoring of Canada’s icy waters, and some Radarsat-2 capabilities that benefit sea- and river ice applications are the multi-polarization options that will improve ice-edge detection, ice-type discrimination and structure information. The many advances in these different Polarimetric Spaceborne platforms were developed to respond to specific needs for radar data in environmental monitoring applications around the world, like : sea- and river-ice monitoring, marine surveillance, disaster management, oil spill detection, snow monitoring, hydrology, mapping, geology, agriculture, soil characterisation, forestry applications (biomass, allometry, height…), urban mapping etc

  16. SAR matrices: automated extraction of information-rich SAR tables from large compound data sets.

    PubMed

    Wassermann, Anne Mai; Haebel, Peter; Weskamp, Nils; Bajorath, Jürgen

    2012-07-23

    We introduce the SAR matrix data structure that is designed to elucidate SAR patterns produced by groups of structurally related active compounds, which are extracted from large data sets. SAR matrices are systematically generated and sorted on the basis of SAR information content. Matrix generation is computationally efficient and enables processing of large compound sets. The matrix format is reminiscent of SAR tables, and SAR patterns revealed by different categories of matrices are easily interpretable. The structural organization underlying matrix formation is more flexible than standard R-group decomposition schemes. Hence, the resulting matrices capture SAR information in a comprehensive manner.

  17. Integration of GB-InSAR, laser scanning and in situ monitoring on the rockslope instability of Mannen/Børa (western Norway)

    NASA Astrophysics Data System (ADS)

    Rouyet, Line; Kristensen, Lene; Derron, Marc-Henri; Michoud, Clément; Harald, Blikra Lars; Michel, Jaboyedoff

    2013-04-01

    This work is part of a master thesis about the use of Ground-Based InSAR for the monitoring of rock instabilities (University of Lausanne in cooperation with the Åknes/Tafjord Early Warning Centre in Norway). Main goals are (1) the evaluation of the GB-InSAR potential to investigate different kinds of instabilities, (2) the combination of data from GB-InSAR, conventional in situ devices and laser scanning to get information about instability behavior and geometry. The rockslope instability of Mannen/Børa is located in Møre of Romsdal County (western Norway). Mannen is a complex rockslide of 15-25 mill. m3 of volume, affecting the left side of the Romsdalen valley. Børa is a large plateau directly located on its south-eastern side and showing signs of activity. In this case, the analysis included GB-InSAR data of 2011 and 2012 campaigns in Børa compared with results of a permanent GB-InSAR in Mannen. The results of continuous monitoring in Mannen (GPS, extensometers, laser-reflectors and tiltmeters) since end of 2009, as well as periodical GPS campaigns on Børa plateau were integrated. The analysis showed a quite regular inter-annual velocity with seasonal effects in Mannen site and a slower movement in Børa. Moreover, it allowed highlighting an area in mid-slope, affected by high variations and periodical inversions of movement in the overlap sector between the two GB-InSAR. The first interpretation of this pattern involves networks of water flow across the slope. A novel point of this site is to have two GB-InSAR systems (one permanent and one temporary) imaging the rockslope with an overlap of views. GB-InSAR results were compared to other types of monitoring data, in terms of spatial coverage (punctual vs. large area), temporal scale (continuous monitoring vs. periodical campaigns) or recorded information (eg. 3D vs. 1D along the LOS). Moreover, a structural geology analysis based on terrestrial and airborne laser scanning data provided information about

  18. 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.

  19. 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

  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. SARS Basics

    MedlinePlus

    ... Laboratory Testing & Specimens SARS-Associated Coronavirus (SARS-CoV) Sequencing Specimen Collection and Management Laboratory Testing and Diagnosis ... person touches a surface or object contaminated with infectious droplets and then touches his or her mouth, ...

  2. Applications of independent component analysis in SAR images

    NASA Astrophysics Data System (ADS)

    Huang, Shiqi; Cai, Xinhua; Hui, Weihua; Xu, Ping

    2009-07-01

    The detection of faint, small and hidden targets in synthetic aperture radar (SAR) image is still an issue for automatic target recognition (ATR) system. How to effectively separate these targets from the complex background is the aim of this paper. Independent component analysis (ICA) theory can enhance SAR image targets and improve signal clutter ratio (SCR), which benefits to detect and recognize faint targets. Therefore, this paper proposes a new SAR image target detection algorithm based on ICA. In experimental process, the fast ICA (FICA) algorithm is utilized. Finally, some real SAR image data is used to test the method. The experimental results verify that the algorithm is feasible, and it can improve the SCR of SAR image and increase the detection rate for the faint small targets.

  3. A comparison of the performance of two types of inertial systems for strapdown airborne gravimetry

    NASA Astrophysics Data System (ADS)

    Deurloo, R. A.; Martin, J.; Bastos, M. L.; Becker, M. H.

    2012-12-01

    Over the past two decades so-called strapdown airborne gravimetry systems have proven to have the potential to compete with more traditional measurement systems such as modified spring gravimeters (e.g. LaCoste & Romberg Air-Sea gravimeters). Strapdown gravimetry systems rely on the integration of high-accuracy data from a GNSS (Global Navigation Satellite System) receiver and from a strapdown IMU (Inertial Measurement Unit). These GNSS/IMU integrated systems have the advantage of being less expensive and more compact, while being easier to use and install than spring gravimeters, which tend to be bulky and require specialized human resources for its operation. In the scope of a research project developed through the collaboration of the University of Porto and the Portuguese Air Force (PAF), an airborne survey was recently performed over the middle and southern area of Continental Portugal using a CASA C212 aircraft. The goal of this survey was to acquire data to assess the performance of different GNSS/IMU systems and associated processing approaches to determine the gravity field and evaluate their potential and effectiveness for airborne gravimetry using different types of airborne platforms, including UAVs (Unmanned Airborne Vehicles). Among the systems on board were a medium-quality (tactical grade) IMU with fiber-optic gyros (FOG), a Litton LN-200, and a high-quality (navigation grade) IMU with ring-laser gyros (RLG), an iMAR RHQ-1003, which are the focus of the present comparison. The advantage of using a strapdown airborne gravimetry system with high-quality inertial sensor is that it allows the complete gravity vector to be determined from the triads of accelerometers and gyros in the IMU (vector gravimetry). On the other hand a medium-quality inertial system is limited to determining only the magnitude of the gravity vector (scalar gravimetry). The limited quality of the gyros of the medium-quality inertial systems does not allow the horizontal

  4. Nyamulagira’s magma plumbing system inferred from 15 years of InSAR

    USGS Publications Warehouse

    Wauthier, Christelle; Cayol, Valérie; Poland, Michael; Kervyn, François; D'Oreye, Nicolas; Hooper, Andrew; Samsonov, Sergei; Tiampo, Kristy; Smets, Benoit; Pyle, D. M.; Mather, T.A.; Biggs, J.

    2013-01-01

    Nyamulagira, located in the east of the Democratic Republic of Congo on the western branch of the East African rift, is Africa’s most active volcano, with an average of one eruption every 3 years since 1938. Owing to the socio-economical context of that region, the volcano lacks ground-based geodetic measurements but has been monitored by interferometric synthetic aperture radar (InSAR) since 1996. A combination of 3D Mixed Boundary Element Method and inverse modelling, taking into account topography and source interactions, is used to interpret InSAR ground displacements associated with eruptive activity in 1996, 2002, 2004, 2006 and 2010. These eruptions can be fitted by models incorporating dyke intrusions, and some (namely the 2006 and 2010 eruptions) require a magma reservoir beneath the summit caldera. We investigate inter-eruptive deformation with a multi-temporal InSAR approach. We propose the following magma plumbing system at Nyamulagira by integrating numerical deformation models with other available data: a deep reservoir (c. 25 km depth) feeds a shallower reservoir (c. 4 km depth); proximal eruptions are fed from the shallow reservoir through dykes while distal eruptions can be fed directly from the deep reservoir. A dyke-like conduit is also present beneath the upper southeastern flank of Nyamulagira.

  5. Image synthesis for SAR system, calibration and processor design

    NASA Technical Reports Server (NTRS)

    Holtzman, J. C.; Abbott, J. L.; Kaupp, V. H.; Frost, V. S.

    1978-01-01

    The Point Scattering Method of simulating radar imagery rigorously models all aspects of the imaging radar phenomena. Its computational algorithms operate on a symbolic representation of the terrain test site to calculate such parameters as range, angle of incidence, resolution cell size, etc. Empirical backscatter data and elevation data are utilized to model the terrain. Additionally, the important geometrical/propagation effects such as shadow, foreshortening, layover, and local angle of incidence are rigorously treated. Applications of radar image simulation to a proposed calibrated SAR system are highlighted: soil moisture detection and vegetation discrimination.

  6. Statistical Approach To Extraction Of Texture In SAR

    NASA Technical Reports Server (NTRS)

    Rignot, Eric J.; Kwok, Ronald

    1992-01-01

    Improved statistical method of extraction of textural features in synthetic-aperture-radar (SAR) images takes account of effects of scheme used to sample raw SAR data, system noise, resolution of radar equipment, and speckle. Treatment of speckle incorporated into overall statistical treatment of speckle, system noise, and natural variations in texture. One computes speckle auto-correlation function from system transfer function that expresses effect of radar aperature and incorporates range and azimuth resolutions.

  7. 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.

  8. Difference in receptor usage between severe acute respiratory syndrome (SARS) coronavirus and SARS-like coronavirus of bat origin.

    PubMed

    Ren, Wuze; Qu, Xiuxia; Li, Wendong; Han, Zhenggang; Yu, Meng; Zhou, Peng; Zhang, Shu-Yi; Wang, Lin-Fa; Deng, Hongkui; Shi, Zhengli

    2008-02-01

    Severe acute respiratory syndrome (SARS) is caused by the SARS-associated coronavirus (SARS-CoV), which uses angiotensin-converting enzyme 2 (ACE2) as its receptor for cell entry. A group of SARS-like CoVs (SL-CoVs) has been identified in horseshoe bats. SL-CoVs and SARS-CoVs share identical genome organizations and high sequence identities, with the main exception of the N terminus of the spike protein (S), known to be responsible for receptor binding in CoVs. In this study, we investigated the receptor usage of the SL-CoV S by combining a human immunodeficiency virus-based pseudovirus system with cell lines expressing the ACE2 molecules of human, civet, or horseshoe bat. In addition to full-length S of SL-CoV and SARS-CoV, a series of S chimeras was constructed by inserting different sequences of the SARS-CoV S into the SL-CoV S backbone. Several important observations were made from this study. First, the SL-CoV S was unable to use any of the three ACE2 molecules as its receptor. Second, the SARS-CoV S failed to enter cells expressing the bat ACE2. Third, the chimeric S covering the previously defined receptor-binding domain gained its ability to enter cells via human ACE2, albeit with different efficiencies for different constructs. Fourth, a minimal insert region (amino acids 310 to 518) was found to be sufficient to convert the SL-CoV S from non-ACE2 binding to human ACE2 binding, indicating that the SL-CoV S is largely compatible with SARS-CoV S protein both in structure and in function. The significance of these findings in relation to virus origin, virus recombination, and host switching is discussed.

  9. SweepSAR: Beam-forming on Receive Using a Reflector-Phased Array Feed Combination for Spaceborne SAR

    NASA Technical Reports Server (NTRS)

    Freeman, A.; Krieger, G.; Rosen, P.; Younis, M.; Johnson, W. T. K.; Huber, S.; Jordan, R.; Moreira, A.

    2012-01-01

    In this paper, an alternative approach is described that is suited for longer wavelength SARs in particular, employing a large, deployable reflector antenna and a much simpler phased array feed. To illuminate a wide swath, a substantial fraction of the phased array feed is excited on transmit to sub-illuminate the reflector. Shorter transmit pulses are required than for conventional SAR. On receive, a much smaller portion of the phased array feed is used to collect the return echo, so that a greater portion of the reflector antenna area is used. The locus of the portion of the phased array used on receive is adjusted using an analog beam steering network, to 'sweep' the receive beam(s) across the illuminated swath, tracking the return echo. This is similar in some respects to the whiskbroom approach to optical sensors, hence the name: SweepSAR.SweepSAR has advantages over conventional SAR in that it requires less transmit power, and if the receive beam is narrow enough, it is relatively immune to range ambiguities. Compared to direct radiating arrays with digital beam- forming, it is much simpler to implement, uses currently available technologies, is better suited for longer wavelength systems, and does not require extremely high data rates or onboard processing.

  10. 1. RUINED PORTION OF SANTA ANA CANAL INTAKE ALONGSIDE SAR3 ...

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

    1. RUINED PORTION OF SANTA ANA CANAL INTAKE ALONGSIDE SAR-3 SYSTEM TUNNEL, JUST TO SOUTH OF SAR-2. VIEW TO SOUTHEAST. - Santa Ana River Hydroelectric System, Abandoned Tunnel, Redlands, San Bernardino County, CA

  11. Joint Offshore Wind Field Monitoring with Spaceborne SAR and Platform-Based Doppler LIDAR Measurements

    NASA Astrophysics Data System (ADS)

    Jacobsen, S.; Lehner, S.; Hieronimus, J.; Schneemann, J.; Kuhn, M.

    2015-04-01

    The increasing demand for renewable energy resources has promoted the construction of offshore wind farms e.g. in the North Sea. While the wind farm layout consists of an array of large turbines, the interrelation of wind turbine wakes with the remaining array is of substantial interest. The downstream spatial evolution of turbulent wind turbine wakes is very complex and depends on manifold parameters such as wind speed, wind direction and ambient atmospheric stability conditions. To complement and validate existing numerical models, corresponding observations are needed. While in-situ measurements with e.g. anemometers provide a time-series at the given location, the merits of ground-based and space- or airborne remote sensing techniques are indisputable in terms of spatial coverage. Active microwave devices, such as Scatterometer and Synthetic Aperture Radar (SAR), have proven their capabilities of providing sea surface wind measurements and particularly SAR images reveal wind variations at a high spatial resolution while retaining the large coverage area. Platform-based Doppler LiDAR can resolve wind fields with a high spatial coverage and repetition rates of seconds to minutes. In order to study the capabilities of both methods for the investigation of small scale wind field structures, we present a direct comparison of observations obtained by high resolution TerraSAR-X (TS-X) X-band SAR data and platform-based LiDAR devices at the North Sea wind farm alpha ventus. We furthermore compare the results with meteorological data from the COSMO-DE model run by the German Weather Service DWD. Our study indicates that the overall agreement between SAR and LiDAR wind fields is good and that under appropriate conditions small scale wind field variations compare significantly well.

  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. Validity and validation of expert (Q)SAR systems.

    PubMed

    Hulzebos, E; Sijm, D; Traas, T; Posthumus, R; Maslankiewicz, L

    2005-08-01

    At a recent workshop in Setubal (Portugal) principles were drafted to assess the suitability of (quantitative) structure-activity relationships ((Q)SARs) for assessing the hazards and risks of chemicals. In the present study we applied some of the Setubal principles to test the validity of three (Q)SAR expert systems and validate the results. These principles include a mechanistic basis, the availability of a training set and validation. ECOSAR, BIOWIN and DEREK for Windows have a mechanistic or empirical basis. ECOSAR has a training set for each QSAR. For half of the structural fragments the number of chemicals in the training set is >4. Based on structural fragments and log Kow, ECOSAR uses linear regression to predict ecotoxicity. Validating ECOSAR for three 'valid' classes results in predictivity of > or = 64%. BIOWIN uses (non-)linear regressions to predict the probability of biodegradability based on fragments and molecular weight. It has a large training set and predicts non-ready biodegradability well. DEREK for Windows predictions are supported by a mechanistic rationale and literature references. The structural alerts in this program have been developed with a training set of positive and negative toxicity data. However, to support the prediction only a limited number of chemicals in the training set is presented to the user. DEREK for Windows predicts effects by 'if-then' reasoning. The program predicts best for mutagenicity and carcinogenicity. Each structural fragment in ECOSAR and DEREK for Windows needs to be evaluated and validated separately.

  14. Quarantine for SARS, Taiwan

    PubMed Central

    King, Chwan-Chuan; Chen, Cathy W. S.; Ho, Mei-Shang; Lee, Jen-Yu; Liu, Feng-Chi; Wu, Yi-Chun

    2005-01-01

    During the 2003 outbreak of severe acute respiratory syndrome (SARS) in Taiwan, >150,000 persons were quarantined, 24 of whom were later found to have laboratory-confirmed SARS-coronavirus (SARS-CoV) infection. Since no evidence exists that SARS-CoV is infective before the onset of symptoms and the quarantined persons were exposed but not symptomatic, we thought the quarantine's effectiveness should be investigated. Using the Taiwan quarantine data, we found that the onset-to-diagnosis time of previously quarantined confirmed case-patients was significantly shortened compared to that for those who had not been quarantined. Thus, quarantine for SARS in Taiwan screened potentially infective persons for swift diagnosis and hospitalization after onset, thereby indirectly reducing infections. Full-scale quarantine measures implemented on April 28 led to a significant improvement in onset-to-diagnosis time of all SARS patients, regardless of previous quarantine status. We discuss the temporal effects of quarantine measures and other interventions on detection and isolation as well as the potential usefulness of quarantine in faster identification of persons with SARS and in improving isolation measures. PMID:15752447

  15. Reduction of Airborne Bacterial Burden in the OR by Installation of Unidirectional Displacement Airflow (UDF) Systems.

    PubMed

    Fischer, Sebastian; Thieves, Martin; Hirsch, Tobias; Fischer, Klaus-Dieter; Hubert, Helmine; Beppler, Steffen; Seipp, Hans-Martin

    2015-08-13

    Intraoperative bacterial contamination is a major risk factor for postoperative wound infections. This study investigated the influence of type of ventilation system on intraoperative airborne bacterial burden before and after installation of unidirectional displacement air flow systems. We microbiologically monitored 1286 surgeries performed by a single surgical team that moved from operating rooms (ORs) equipped with turbulent mixing ventilation (TMV, according to standard DIN-1946-4 [1999], ORs 1, 2, and 3) to ORs with unidirectional displacement airflow (UDF, according to standard DIN-1946-4, annex D [2008], ORs 7 and 8). The airborne bacteria were collected intraoperatively with sedimentation plates. After incubation for 48 h, we analyzed the average number of bacteria per h, peak values, and correlation to surgery duration. In addition, we compared the last 138 surgeries in ORs 1-3 with the first 138 surgeries in ORs 7 and 8. Intraoperative airborne bacterial burden was 5.4 CFU/h, 5.5 CFU/h, and 6.1 CFU/h in ORs 1, 2, and 3, respectively. Peak values of burden were 10.7 CFU/h, 11.1 CFU/h, and 11.0 CFU/h in ORs 1, 2, and 3, respectively). With the UDF system, the intraoperative airborne bacterial burden was reduced to 0.21 CFU/h (OR 7) and 0.35 CFU/h (OR 8) on average (p<0.01). Accordingly, peak values decreased to 0.9 CFU/h and 1.0 CFU/h in ORs 7 and 8, respectively (p<0.01). Airborne bacterial burden increased linearly with surgery duration in ORs 1-3, but the UDF system in ORs 7 and 8 kept bacterial levels constantly low (<3 CFU/h). A comparison of the last 138 surgeries before with the first 138 surgeries after changing ORs revealed a 94% reduction in average airborne bacterial burden (5 CFU/h vs. 0.29 CFU/h, p<0.01). The unidirectional displacement airflow, which fulfills the requirements of standard DIN-1946-4 annex D of 2008, is an effective ventilation system that reduces airborne bacterial burden under real clinical conditions by more than 90

  16. Observations with the GISMOS Airborne Radio Occultation System

    NASA Astrophysics Data System (ADS)

    Muradyan, Paytsar; Haase, Jennifer; Garrison, James; Lulich, Tyler; Xie, Feiqin

    2010-05-01

    The spatial sample density of temperature and moisture profiles derived from the current spaceborne GPS radio occultation (RO) constellation is limited by the number of occultation satellites in operation. With the current RO satellite configuration, only one RO profile per day is typically available in a 160,000 square kilometer area in the mid-latitude and tropics and slightly more in high latitudes. The airborne RO technique, which has the GPS receiver onboard an airplane, offers flexibility and much denser sampling for targeted observation within 400 km of the aircraft, and provides comparable high vertical resolution to that of the spaceborne case. With an airborne system, targeted measurements can be planned in an optimal geometry to study the accuracy of RO measurements in the lower troposphere where strong vertical gradients in moisture might lead to disruption of signal tracking. These dense measurements can also be used to test assimilation techniques of refractivity and lower tropospheric moisture derived from RO data. In February 2008, the GNSS Instrument System for Multistatic and Occultation Sensing (GISMOS), developed at Purdue University, was successfully deployed on the NSF HIAPER aircraft for series of research flights in the Gulf of Mexico coastal region to validate the airborne observing system. During this campaign, occultation observations were collected in conjunction with supplemental radiosonde and dropsonde soundings. RO signals were recorded using side-looking GPS antennas and dual frequency GPS receivers. However, these conventional phase-locked-loop GPS receivers cannot always track the signal in the lower troposphere, where there are rapid phase accelerations caused by highly variable moisture structures. To extend the observations deeper into the atmosphere, the raw signal from occulting satellites is recorded at 10MHz sampling interval by a GPS recording system (GRS). Open-loop (OL) tracking, which replaces the traditional GPS

  17. InSAR Scientific Computing Environment

    NASA Technical Reports Server (NTRS)

    Rosen, Paul A.; Sacco, Gian Franco; Gurrola, Eric M.; Zabker, Howard A.

    2011-01-01

    This computing environment is the next generation of geodetic image processing technology for repeat-pass Interferometric Synthetic Aperture (InSAR) sensors, identified by the community as a needed capability to provide flexibility and extensibility in reducing measurements from radar satellites and aircraft to new geophysical products. This software allows users of interferometric radar data the flexibility to process from Level 0 to Level 4 products using a variety of algorithms and for a range of available sensors. There are many radar satellites in orbit today delivering to the science community data of unprecedented quantity and quality, making possible large-scale studies in climate research, natural hazards, and the Earth's ecosystem. The proposed DESDynI mission, now under consideration by NASA for launch later in this decade, would provide time series and multiimage measurements that permit 4D models of Earth surface processes so that, for example, climate-induced changes over time would become apparent and quantifiable. This advanced data processing technology, applied to a global data set such as from the proposed DESDynI mission, enables a new class of analyses at time and spatial scales unavailable using current approaches. This software implements an accurate, extensible, and modular processing system designed to realize the full potential of InSAR data from future missions such as the proposed DESDynI, existing radar satellite data, as well as data from the NASA UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar), and other airborne platforms. The processing approach has been re-thought in order to enable multi-scene analysis by adding new algorithms and data interfaces, to permit user-reconfigurable operation and extensibility, and to capitalize on codes already developed by NASA and the science community. The framework incorporates modern programming methods based on recent research, including object-oriented scripts controlling legacy and

  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. Wavemill Product Assessment- Defining Products and Evaluating Potential Performance from a Novel Spaceborne Interferometric SAR

    NASA Astrophysics Data System (ADS)

    Cotton, P. D.; Gommenginger, C.; Martin, A.; Marquez, J.; Burbidge, G.; Quilfen, Y.; Chapron, B.; Reppucci, A.; Buck, C.

    2016-08-01

    Ocean Surface Currents are one of the most important ocean properties for oceanographers and operators in the maritime domain. Improved monitoring of ocean currents is systematically the number one requirement that emerges from any science or end user requirement surveys.Wavemill is a novel hybrid interferometric SAR system first proposed by ESA/ESTEC [Buck, 2005]. It offers the possibility of generating two-dimensional wide swath, high resolution, high precision maps of surface current vectors and ocean topography [Buck et al., 2009]. Based on a single spacecraft, it avoids the difficulties of synchronisation and baseline estimation associated with other interferometric SAR systems based on two or more satellites (e.g. the "cartwheel" or "helix" concept).The Wavemill concept has developed steadily since its first inception in 2005. A number of Wavemill studies in recent years have gradually put together facts and figures to support the case for Wavemill as a possible space-borne mission.The Wavemill Product Assessment study (WaPA) aimed to define the scientific capabilities and limitations of a spaceborne Wavemill instrument in preparation for a possible submission of the Wavemill concept as a candidate Earth Explorer Core mission. The WaPA project team brought together expert scientists and engineers in the field of SAR imaging of ocean currents, and included the National Oceanography Centre (UK), Starlab (Spain), IFREMER (France) and Airbus Defence and Space (UK). Overall project management was provided by Satellite Oceanographic Consultants (UK). The approach taken included:- A review of SAR imaging of ocean currents in along-track interferometric mode to learn from previous experiments and modelling what key phenomena need to be accounted for to determine the true performance of a spaceborne Wavemill system- Validation of proposed Wavemill primary products based on Wavemill airborne proof-of-concept data and numerical simulations to determine the capabilities

  20. Clinical review: SARS - lessons in disaster management.

    PubMed

    Hawryluck, Laura; Lapinsky, Stephen E; Stewart, Thomas E

    2005-08-01

    Disaster management plans have traditionally been required to manage major traumatic events that create a large number of victims. Infectious diseases, whether they be natural (e.g. SARS [severe acute respiratory syndrome] and influenza) or the result of bioterrorism, have the potential to create a large influx of critically ill into our already strained hospital systems. With proper planning, hospitals, health care workers and our health care systems can be better prepared to deal with such an eventuality. This review explores the Toronto critical care experience of coping in the SARS outbreak disaster. Our health care system and, in particular, our critical care system were unprepared for this event, and as a result the impact that SARS had was worse than it could have been. Nonetheless, we were able to organize a response rapidly during the outbreak. By describing our successes and failures, we hope to help others to learn and avoid the problems we encountered as they develop their own disaster management plans in anticipation of similar future situations.

  1. Alaska Synthetic Aperture Radar (SAR) Facility science data processing architecture

    NASA Technical Reports Server (NTRS)

    Hilland, Jeffrey E.; Bicknell, Thomas; Miller, Carol L.

    1991-01-01

    The paper describes the architecture of the Alaska SAR Facility (ASF) at Fairbanks, being developed to generate science data products for supporting research in sea ice motion, ice classification, sea-ice-ocean interaction, glacier behavior, ocean waves, and hydrological and geological study areas. Special attention is given to the individual substructures of the ASF: the Receiving Ground Station (RGS), the SAR Processor System, and the Interactive Image Analysis System. The SAR data will be linked to the RGS by the ESA ERS-1 and ERS-2, the Japanese ERS-1, and the Canadian Radarsat.

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  3. InSAR datum connection using GNSS-augmented radar transponders

    NASA Astrophysics Data System (ADS)

    Mahapatra, Pooja; der Marel, Hans van; van Leijen, Freek; Samiei-Esfahany, Sami; Klees, Roland; Hanssen, Ramon

    2018-01-01

    Deformation estimates from Interferometric Synthetic Aperture Radar (InSAR) are relative: they form a `free' network referred to an arbitrary datum, e.g. by assuming a reference point in the image to be stable. However, some applications require `absolute' InSAR estimates, i.e. expressed in a well-defined terrestrial reference frame, e.g. to compare InSAR results with those of other techniques. We propose a methodology based on collocated InSAR and Global Navigation Satellite System (GNSS) measurements, achieved by rigidly attaching phase-stable millimetre-precision compact active radar transponders to GNSS antennas. We demonstrate this concept through a simulated example and practical case studies in the Netherlands.

  4. Modified Polar-Format Software for Processing SAR Data

    NASA Technical Reports Server (NTRS)

    Chen, Curtis

    2003-01-01

    HMPF is a computer program that implements a modified polar-format algorithm for processing data from spaceborne synthetic-aperture radar (SAR) systems. Unlike prior polar-format processing algorithms, this algorithm is based on the assumption that the radar signal wavefronts are spherical rather than planar. The algorithm provides for resampling of SAR pulse data from slant range to radial distance from the center of a reference sphere that is nominally the local Earth surface. Then, invoking the projection-slice theorem, the resampled pulse data are Fourier-transformed over radial distance, arranged in the wavenumber domain according to the acquisition geometry, resampled to a Cartesian grid, and inverse-Fourier-transformed. The result of this process is the focused SAR image. HMPF, and perhaps other programs that implement variants of the algorithm, may give better accuracy than do prior algorithms for processing strip-map SAR data from high altitudes and may give better phase preservation relative to prior polar-format algorithms for processing spotlight-mode SAR data.

  5. 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.

  6. L-band InSAR Penetration Depth Experiment, North Slope Alaska

    NASA Astrophysics Data System (ADS)

    Muskett, Reginald

    2017-04-01

    Since the first spacecraft-based synthetic aperture radar (SAR) mission NASA's SEASAT in 1978 radars have been flown in Low Earth Orbit (LEO) by other national space agencies including the Canadian Space Agency, European Space Agency, India Space Research Organization and the Japanese Aerospace Exploration Agency. Improvements in electronics, miniaturization and production have allowed for the deployment of SAR systems on aircraft for usage in agriculture, hazards assessment, land-use management and planning, meteorology, oceanography and surveillance. LEO SAR systems still provide a range of needful and timely information on large and small-scale weather conditions like those found across the Arctic where ground-base weather radars currently provide limited coverage. For investigators of solid-earth deformation attention must be given to the atmosphere on Interferometric SAR (InSAR) by aircraft and spacecraft multi-pass operations. Because radar has the capability to penetrate earth materials at frequencies from the P- to X-band attention must be given to the frequency dependent penetration depth and volume scattering. This is the focus of our new research project: to test the penetration depth of L-band SAR/InSAR by aircraft and spacecraft systems at a test site in Arctic Alaska using multi-frequency analysis and progressive burial of radar mesh-reflectors at measured depths below tundra while monitoring environmental conditions. Knowledge of the L-band penetration depth on lowland Arctic tundra is necessary to constrain analysis of carbon mass balance and hazardous conditions arising form permafrost degradation and thaw, surface heave and subsidence and thermokarst formation at local and regional scales.

  7. Application of InSAR to detection of localized subsidence and its effects on flood protection infrastructure in the New Orleans area

    NASA Astrophysics Data System (ADS)

    Jones, Cathleen; Blom, Ronald; Latini, Daniele

    2014-05-01

    The vulnerability of the United States Gulf of Mexico coast to inundation has received increasing attention in the years since hurricanes Katrina and Rita. Flood protection is a challenge throughout the area, but the population density and cumulative effect of historic subsidence makes it particularly difficult in the New Orleans area. Analysis of historical and continuing geodetic measurements identifies a surprising degree of complexity in subsidence (Dokka 2011), including regions that are subsiding at rates faster than those considered during planning for hurricane protection and for coastal restoration projects. Improved measurements are possible through combining traditional single point, precise geodetic data with interferometric synthetic aperture radar (InSAR) observations for to obtain geographically dense constraints on surface deformation. The Gulf Coast environment is very challenging for InSAR techniques, especially with systems not designed for interferometry. We are applying pair-wise InSAR to longer wavelength (L-band, 24 cm) synthetic aperture radar data acquired with the airborne UAVSAR instrument (http://uavsar.jpl.nasa.gov/) to detect localized change impacting flood protection infrastructure in the New Orleans area during the period from 2009 - 2013. Because aircraft motion creates large-scale image artifacts across the scene, we focus on localized areas on and near flood protection infrastructure to identify anomalous change relative to the surrounding area indicative of subsidence, structural deformation, and/or seepage (Jones et al., 2011) to identify areas where problems exist. C-band and particularly X-band radar returns decorrelate over short time periods in rural or less urbanized areas and are more sensitive to atmospheric affects, necessitating more elaborate analysis techniques or, at least, a strict limit on the temporal baseline. The new generation of spaceborne X-band SAR acquisitions ensure relatively high frequency of

  8. Program Merges SAR Data on Terrain and Vegetation Heights

    NASA Technical Reports Server (NTRS)

    Siqueira, Paul; Hensley, Scott; Rodriguez, Ernesto; Simard, Marc

    2007-01-01

    X/P Merge is a computer program that estimates ground-surface elevations and vegetation heights from multiple sets of data acquired by the GeoSAR instrument [a terrain-mapping synthetic-aperture radar (SAR) system that operates in the X and bands]. X/P Merge software combines data from X- and P-band digital elevation models, SAR backscatter magnitudes, and interferometric correlation magnitudes into a simplified set of output topographical maps of ground-surface elevation and tree height.

  9. Monitoring of precursor landslide surface deformation using InSAR image in Kuchi-Sakamoto, Shizuoka Prefecture, Japan

    NASA Astrophysics Data System (ADS)

    Sato, H. P.; Nakajima, H.; Nakano, T.; Daimaru, H.

    2014-12-01

    Synthetic Aperture Radar (SAR) is the technique to obtain ground surface images using microwave that is emitted from and received on the antenna. The Kuchi-Sakamoto area, 2.2 km2 in precipitous mountains, central Japan, has suffered from frequent landslides, and slow landslide surface deformation has been monitored by on-site extensometer; however, such the monitoring method cannot detect the deformation in the whole area. Because satellite InSAR is effective tool to monitor slow landslide suface deformation, it is a promising tool for detecting precursor deformation and preparing effective measures against serious landslide disasters. In this study Advanced Land Observing Satellite (ALOS) / Phased Array type L-band SAR (PALSAR) data were used, and InSAR images were produced from the PALSAR data that were observed between 5 Sep 2008 and 21 Oct 2008 (from descending orbit) and between 20 Jul 2008 and 7 Sep 2009 (from ascending orbit). InSAR image from descending orbit was found to detect clear precursor landslide surface deformation on a slope; however, InSAR image on ascending orbit did not always detect clear precursor deformation. It is thought to be related with atmospheric moisture condition, length of observation baseline and so on. Furthermore, after phase unwrapping on InSAR images, 2.5-dimensional deformation was analized. This analysis needed both ascending and descending InSAR images and culculated quasi east-west deformation component (Figs. (a) and (b)) and quasi up-down deformation component (Figs. (c) and (d)). The resulting 2.5D calculation gave westward deformation and mixture of upward and downward deformations on the precursor landslide surface deformation slope (blue circles in Figs. (c) and (d)), where remarkable disrupted deep landslide occurred during Nov 2012 and 25 Jun 2013, judging from result of airborne LiDAR survey and field survey; the occurrence date is not precisely identified. The figure remains the issue that eliminating "real

  10. Advanced digital SAR processing study

    NASA Technical Reports Server (NTRS)

    Martinson, L. W.; Gaffney, B. P.; Liu, B.; Perry, R. P.; Ruvin, A.

    1982-01-01

    A highly programmable, land based, real time synthetic aperture radar (SAR) processor requiring a processed pixel rate of 2.75 MHz or more in a four look system was designed. Variations in range and azimuth compression, number of looks, range swath, range migration and SR mode were specified. Alternative range and azimuth processing algorithms were examined in conjunction with projected integrated circuit, digital architecture, and software technologies. The advaced digital SAR processor (ADSP) employs an FFT convolver algorithm for both range and azimuth processing in a parallel architecture configuration. Algorithm performace comparisons, design system design, implementation tradeoffs and the results of a supporting survey of integrated circuit and digital architecture technologies are reported. Cost tradeoffs and projections with alternate implementation plans are presented.

  11. Second International Airborne Remote Sensing Conference and Exhibition

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The conference provided four days of displays and scientific presentations on applications, technology, a science of sub-orbital data gathering and analysis. The twelve displayed aircraft equipped with sophisticated instrumentation represented a wide range of environmental and reconnaissance missions,including marine pollution control, fire detection, Open Skies Treaty verification, thermal mapping, hydrographical measurements, military research, ecological and agricultural observations, geophysical research, atmospheric and meterological observations, and aerial photography. The U.S. Air Force and the On-Site Inspection Agency displayed the new Open Skies Treaty verification Boeing OC 135B that promotes international monitoring of military forces and activities. SRl's Jetstream uses foliage and ground penetrating SAR for forest inventories, toxic waste delineation, and concealed target and buried unexploded ordnance detection. Earth Search Sciences's Gulfstream 1 with prototype miniaturized airborne hyperspectral imaging equipment specializes in accurate mineral differentiation, low-cost hydrocarbon exploration, and nonproliferation applications. John E. Chance and the U.S. Army Corps of Engineers displayed the Bell 2 helicopter with SHOALS that performs hydrographic surveying of navigation projects, coastal environment assessment, and nautical charting surveys. Bechtel Nevada and U.S. DOE displayed both the Beech King AIR B-200 platform equipped to provide first response to nuclear accidents and routine environmental surveillance, and the MBB BO-105 helicopter used in spectral analysis for environmental assessment and military appraisal. NASA Ames Research Center's high-altitude Lockheed ER-2 assists in earth resources monitoring research in atmospheric chemistry, oceanography, and electronic sensors; ozone and greenhouse studies and satellite calibration and data validation. Ames also showcased the Learjet 24 Airborne Observatory that completed missions in Venus

  12. 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.

  13. InSAR observations of active volcanoes in Latin America

    NASA Astrophysics Data System (ADS)

    Morales Rivera, A. M.; Chaussard, E.; Amelung, F.

    2012-12-01

    Over the last decade satellite-based interferometric synthetic aperture radar (InSAR) has developed into a well-known technique to gauge the status of active volcanoes. The InSAR technique can detect the ascent of magma to shallow levels of the volcanic plumbing system because new arriving magma pressurizes the system. This is likely associated with the inflation of the volcanic edifice and the surroundings. Although the potential of InSAR to detect magma migration is well known, the principal limitation was that only for few volcanoes frequent observations were acquired. The ALOS-1 satellite of the Japanese Aerospace Exploration Agency (JAXA) acquired a global L-band data set of 15-20 acquisitions during 2006-2011. Here we use ALOS InSAR and Small Baseline (SB) time-series methods for a ground deformation survey of Latin America with emphasis on the northern Andes. We present time-dependent ground deformation data for the volcanoes in Colombia, Ecuador and Peru and interpret the observations in terms of the dynamics of the volcanic systems.

  14. 25. SAR2, SHOWING TAILRACE REPAIRS AFTER FLOOD OF JANUARY, 1916; ...

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

    25. SAR-2, SHOWING TAILRACE REPAIRS AFTER FLOOD OF JANUARY, 1916; ALSO FLUME CONNECTION TO MENTONE SYSTEM. SCE negative no. 3904, July 13, 1916. Photograph by G. Haven Bishop. - Santa Ana River Hydroelectric System, SAR-2 Powerhouse, Redlands, San Bernardino County, CA

  15. SAR and LIDAR fusion: experiments and applications

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  16. Geodetic imaging of tectonic deformation with InSAR

    NASA Astrophysics Data System (ADS)

    Fattahi, Heresh

    Precise measurements of ground deformation across the plate boundaries are crucial observations to evaluate the location of strain localization and to understand the pattern of strain accumulation at depth. Such information can be used to evaluate the possible location and magnitude of future earthquakes. Interferometric Synthetic Aperture Radar (InSAR) potentially can deliver small-scale (few mm/yr) ground displacement over long distances (hundreds of kilometers) across the plate boundaries and over continents. However, Given the ground displacement as our signal of interest, the InSAR observations of ground deformation are usually affected by several sources of systematic and random noises. In this dissertation I identify several sources of systematic and random noise, develop new methods to model and mitigate the systematic noise and to evaluate the uncertainty of the ground displacement measured with InSAR. I use the developed approach to characterize the tectonic deformation and evaluate the rate of strain accumulation along the Chaman fault system, the western boundary of the India with Eurasia tectonic plates. I evaluate the bias due to the topographic residuals in the InSAR range-change time-series and develope a new method to estimate the topographic residuals and mitigate the effect from the InSAR range-change time-series (Chapter 2). I develop a new method to evaluate the uncertainty of the InSAR velocity field due to the uncertainty of the satellite orbits (Chapter 3) and a new algorithm to automatically detect and correct the phase unwrapping errors in a dense network of interferograms (Chapter 4). I develop a new approach to evaluate the impact of systematic and stochastic components of the tropospheric delay on the InSAR displacement time-series and its uncertainty (Chapter 5). Using the new InSAR time-series approach developed in the previous chapters, I study the tectonic deformation across the western boundary of the India plate with Eurasia and

  17. Surface Water Detection Using Fused Synthetic Aperture Radar, Airborne LiDAR and Optical Imagery

    NASA Astrophysics Data System (ADS)

    Braun, A.; Irwin, K.; Beaulne, D.; Fotopoulos, G.; Lougheed, S. C.

    2016-12-01

    Each remote sensing technique has its unique set of strengths and weaknesses, but by combining techniques the classification accuracy can be increased. The goal of this project is to underline the strengths and weaknesses of Synthetic Aperture Radar (SAR), LiDAR and optical imagery data and highlight the opportunities where integration of the three data types can increase the accuracy of identifying water in a principally natural landscape. The study area is located at the Queen's University Biological Station, Ontario, Canada. TerraSAR-X (TSX) data was acquired between April and July 2016, consisting of four single polarization (HH) staring spotlight mode backscatter intensity images. Grey-level thresholding is used to extract surface water bodies, before identifying and masking zones of radar shadow and layover by using LiDAR elevation models to estimate the canopy height and applying simple geometry algorithms. The airborne LiDAR survey was conducted in June 2014, resulting in a discrete return dataset with a density of 1 point/m2. Radiometric calibration to correct for range and incidence angle is applied, before classifying the points as water or land based on corrected intensity, elevation, roughness, and intensity density. Panchromatic and multispectral (4-band) imagery from Quickbird was collected in September 2005 at spatial resolutions of 0.6m and 2.5m respectively. Pixel-based classification is applied to identify and distinguish water bodies from land. A classification system which inputs SAR-, LiDAR- and optically-derived water presence models in raster formats is developed to exploit the strengths and weaknesses of each technique. The total percentage of water detected in the sample area for SAR backscatter, LiDAR intensity, and optical imagery was 27%, 19% and 18% respectively. The output matrix of the classification system indicates that in over 72% of the study area all three methods agree on the classification. Analysis was specifically targeted

  18. Modeling of SAR signatures of shallow water ocean topography

    NASA Technical Reports Server (NTRS)

    Shuchman, R. A.; Kozma, A.; Kasischke, E. S.; Lyzenga, D. R.

    1984-01-01

    A hydrodynamic/electromagnetic model was developed to explain and quantify the relationship between the SEASAT synthetic aperture radar (SAR) observed signatures and the bottom topography of the ocean in the English Channel region of the North Sea. The model uses environmental data and radar system parameters as inputs and predicts SAR-observed backscatter changes over topographic changes in the ocean floor. The model results compare favorably with the actual SEASAT SAR observed backscatter values. The developed model is valid for only relatively shallow water areas (i.e., less than 50 meters in depth) and suggests that for bottom features to be visible on SAR imagery, a moderate to high velocity current and a moderate wind must be present.

  19. Risk Factors for SARS among Persons without Known Contact with SARS Patients, Beijing, China

    PubMed Central

    Wu, Jiang; Xu, Fujie; Zhou, Weigong; Feikin, Daniel R.; Lin, Chang-Ying; He, Xiong; Zhu, Zonghan; Liang, Wannian; Chin, Daniel P.

    2004-01-01

    Most cases of severe acute respiratory syndrome (SARS) have occurred in close contacts of SARS patients. However, in Beijing, a large proportion of SARS cases occurred in persons without such contact. We conducted a case-control study in Beijing that compared exposures of 94 unlinked, probable SARS patients with those of 281 community-based controls matched for age group and sex. Case-patients were more likely than controls to have chronic medical conditions or to have visited fever clinics (clinics at which possible SARS patients were separated from other patients), eaten outside the home, or taken taxis frequently. The use of masks was strongly protective. Among 31 case-patients for whom convalescent-phase (>21 days) sera were available, 26% had immunoglobulin G to SARS-associated coronavirus. Our finding that clinical SARS was associated with visits to fever clinics supports Beijing’s strategy of closing clinics with poor infection-control measures. Our finding that mask use lowered the risk for disease supports the community’s use of this strategy. PMID:15030685

  20. L-band InSAR Penetration Depth Experiment, North Slope Alaska

    NASA Astrophysics Data System (ADS)

    Muskett, R. R.

    2017-12-01

    Since the first spacecraft-based synthetic aperture radar (SAR) mission NASA's SEASAT in 1978 radars have been flown in Low Earth Orbit (LEO) by other national space agencies including the Canadian Space Agency, European Space Agency, India Space Research Organization and the Japanese Aerospace Exploration Agency. Improvements in electronics, miniaturization and production have allowed for the deployment of SAR systems on aircraft for usage in agriculture, hazards assessment, land-use management and planning, meteorology, oceanography and surveillance. LEO SAR systems still provide a range of needful and timely information on large and small-scale weather conditions like those found across the Arctic where ground-base weather radars currently provide limited coverage. For investigators of solid-earth deformation attention must be given to the atmosphere on Interferometric SAR (InSAR) by aircraft and spacecraft multi-pass operations. Because radar has the capability to penetrate earth materials at frequencies from the P- to X-band attention must be given to the frequency dependent penetration depth and volume scattering. This is the focus of our new research project: to test the penetration depth of L-band SAR/InSAR by aircraft and spacecraft systems at a test site in Arctic Alaska using multi-frequency analysis and progressive burial of radar mesh-reflectors at measured depths below tundra while monitoring environmental conditions. Knowledge of the L-band penetration depth on lowland Arctic tundra is necessary to constrain analysis of carbon mass balance and hazardous conditions arising form permafrost degradation and thaw, surface heave and subsidence and thermokarst formation at local and regional scales. Ref.: Geoscience and Environment Protection, vol. 5, no. 3, p. 14-30, 2017. DOI: 10.4236/gep.2017.53002.

  1. Severe acute respiratory syndrome (SARS)

    MedlinePlus

    SARS; Respiratory failure - SARS ... Complications may include: Respiratory failure Liver failure Heart failure ... 366. McIntosh K, Perlman S. Coronaviruses, including severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). ...

  2. Segmentation of Oil Spills on Side-Looking Airborne Radar Imagery with Autoencoders.

    PubMed

    Gallego, Antonio-Javier; Gil, Pablo; Pertusa, Antonio; Fisher, Robert B

    2018-03-06

    In this work, we use deep neural autoencoders to segment oil spills from Side-Looking Airborne Radar (SLAR) imagery. Synthetic Aperture Radar (SAR) has been much exploited for ocean surface monitoring, especially for oil pollution detection, but few approaches in the literature use SLAR. Our sensor consists of two SAR antennas mounted on an aircraft, enabling a quicker response than satellite sensors for emergency services when an oil spill occurs. Experiments on TERMA radar were carried out to detect oil spills on Spanish coasts using deep selectional autoencoders and RED-nets (very deep Residual Encoder-Decoder Networks). Different configurations of these networks were evaluated and the best topology significantly outperformed previous approaches, correctly detecting 100% of the spills and obtaining an F 1 score of 93.01% at the pixel level. The proposed autoencoders perform accurately in SLAR imagery that has artifacts and noise caused by the aircraft maneuvers, in different weather conditions and with the presence of look-alikes due to natural phenomena such as shoals of fish and seaweed.

  3. Segmentation of Oil Spills on Side-Looking Airborne Radar Imagery with Autoencoders

    PubMed Central

    2018-01-01

    In this work, we use deep neural autoencoders to segment oil spills from Side-Looking Airborne Radar (SLAR) imagery. Synthetic Aperture Radar (SAR) has been much exploited for ocean surface monitoring, especially for oil pollution detection, but few approaches in the literature use SLAR. Our sensor consists of two SAR antennas mounted on an aircraft, enabling a quicker response than satellite sensors for emergency services when an oil spill occurs. Experiments on TERMA radar were carried out to detect oil spills on Spanish coasts using deep selectional autoencoders and RED-nets (very deep Residual Encoder-Decoder Networks). Different configurations of these networks were evaluated and the best topology significantly outperformed previous approaches, correctly detecting 100% of the spills and obtaining an F1 score of 93.01% at the pixel level. The proposed autoencoders perform accurately in SLAR imagery that has artifacts and noise caused by the aircraft maneuvers, in different weather conditions and with the presence of look-alikes due to natural phenomena such as shoals of fish and seaweed. PMID:29509720

  4. 34. SAR2, WATERDRIVEN EXCITERS. SCE negative no. 10329, November 1, ...

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

    34. SAR-2, WATER-DRIVEN EXCITERS. SCE negative no. 10329, November 1, 1923. Photograph by G. Haven Bishop. - Santa Ana River Hydroelectric System, SAR-2 Powerhouse, Redlands, San Bernardino County, CA

  5. 1. DOMESTIC WATER SUPPLY TREATMENT HOUSE, ON PENSTOCK ABOVE SAR1. ...

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

    1. DOMESTIC WATER SUPPLY TREATMENT HOUSE, ON PENSTOCK ABOVE SAR-1. VIEW TO NORTWEST. - Santa Ana River Hydroelectric System, SAR-1 Domestic Water Supply Treatment House, Redlands, San Bernardino County, CA

  6. 32. SAR1, VIEW FROM STABLE LOFT. SCE negative no. 10319, ...

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

    32. SAR-1, VIEW FROM STABLE LOFT. SCE negative no. 10319, November 1, 1923. Photograph by G. Haven Bishop. - Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San Bernardino County, CA

  7. Development of an Airborne High Resolution TV System (AHRTS)

    DTIC Science & Technology

    1975-11-01

    GOVT ACCESSION NO READ INSTRUCTIONS BEFORE COMPLETING FORM JP RECIPIENT’S CATALOG NUMBER DEVELOPMENT OF AN ^IRBORNE HIGH JESOLUTION TV SYSTEM...c. Sytem Elements The essential Airborne Subsystem elements of camera, video tape recorder, transmitter and antennas are required to have...The camera operated over the 3000:1 light change as required. A solar shutter was Incorporated to protect the vidicon from damage from direct view

  8. Circular SAR GMTI

    NASA Astrophysics Data System (ADS)

    Page, Douglas; Owirka, Gregory; Nichols, Howard; Scarborough, Steven

    2014-06-01

    We describe techniques for improving ground moving target indication (GMTI) performance in multi-channel synthetic aperture radar (SAR) systems. Our approach employs a combination of moving reference processing (MRP) to compensate for defocus of moving target SAR responses and space-time adaptive processing (STAP) to mitigate the effects of strong clutter interference. Using simulated moving target and clutter returns, we demonstrate focusing of the target return using MRP, and discuss the effect of MRP on the clutter response. We also describe formation of adaptive degrees of freedom (DOFs) for STAP filtering of MRP processed data. For the simulated moving target in clutter example, we demonstrate improvement in the signal to interference plus noise (SINR) loss compared to more standard algorithm configurations. In addition to MRP and STAP, the use of tracker feedback, false alarm mitigation, and parameter estimation techniques are also described. A change detection approach for reducing false alarms from clutter discretes is outlined, and processing of a measured data coherent processing interval (CPI) from a continuously orbiting platform is described. The results demonstrate detection and geolocation of a high-value target under track. The endoclutter target is not clearly visible in single-channel SAR chips centered on the GMTI track prediction. Detections are compared to truth data before and after geolocation using measured angle of arrival (AOA).

  9. Airborne electromagnetic bathymetry investigations in Port Lincoln, South Australia - comparison with an equivalent floating transient electromagnetic system

    NASA Astrophysics Data System (ADS)

    Vrbancich, Julian

    2011-09-01

    Helicopter time-domain airborne electromagnetic (AEM) methodology is being investigated as a reconnaissance technique for bathymetric mapping in shallow coastal waters, especially in areas affected by water turbidity where light detection and ranging (LIDAR) and hyperspectral techniques may be limited. Previous studies in Port Lincoln, South Australia, used a floating AEM time-domain system to provide an upper limit to the expected bathymetric accuracy based on current technology for AEM systems. The survey lines traced by the towed floating system were also flown with an airborne system using the same transmitter and receiver electronic instrumentation, on two separate occasions. On the second occasion, significant improvements had been made to the instrumentation to reduce the system self-response at early times. A comparison of the interpreted water depths obtained from the airborne and floating systems is presented, showing the degradation in bathymetric accuracy obtained from the airborne data. An empirical data correction method based on modelled and observed EM responses over deep seawater (i.e. a quasi half-space response) at varying survey altitudes, combined with known seawater conductivity measured during the survey, can lead to significant improvements in interpreted water depths and serves as a useful method for checking system calibration. Another empirical data correction method based on observed and modelled EM responses in shallow water was shown to lead to similar improvements in interpreted water depths; however, this procedure is notably inferior to the quasi half-space response because more parameters need to be assumed in order to compute the modelled EM response. A comparison between the results of the two airborne surveys in Port Lincoln shows that uncorrected data obtained from the second airborne survey gives good agreement with known water depths without the need to apply any empirical corrections to the data. This result significantly

  10. A Fast Superpixel Segmentation Algorithm for PolSAR Images Based on Edge Refinement and Revised Wishart Distance

    PubMed Central

    Zhang, Yue; Zou, Huanxin; Luo, Tiancheng; Qin, Xianxiang; Zhou, Shilin; Ji, Kefeng

    2016-01-01

    The superpixel segmentation algorithm, as a preprocessing technique, should show good performance in fast segmentation speed, accurate boundary adherence and homogeneous regularity. A fast superpixel segmentation algorithm by iterative edge refinement (IER) works well on optical images. However, it may generate poor superpixels for Polarimetric synthetic aperture radar (PolSAR) images due to the influence of strong speckle noise and many small-sized or slim regions. To solve these problems, we utilized a fast revised Wishart distance instead of Euclidean distance in the local relabeling of unstable pixels, and initialized unstable pixels as all the pixels substituted for the initial grid edge pixels in the initialization step. Then, postprocessing with the dissimilarity measure is employed to remove the generated small isolated regions as well as to preserve strong point targets. Finally, the superiority of the proposed algorithm is validated with extensive experiments on four simulated and two real-world PolSAR images from Experimental Synthetic Aperture Radar (ESAR) and Airborne Synthetic Aperture Radar (AirSAR) data sets, which demonstrate that the proposed method shows better performance with respect to several commonly used evaluation measures, even with about nine times higher computational efficiency, as well as fine boundary adherence and strong point targets preservation, compared with three state-of-the-art methods. PMID:27754385

  11. 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.

  12. [Impacts of airborne particulate matter and its components on respiratory system health].

    PubMed

    Cao, L M; Zhou, Y; Zhang, Z; Sun, W W; Mu, G; Chen, W H

    2016-12-06

    Nowadays, particulate air pollution has been a global environmental problem. Numerous studies has shown that long-term exposure to high level of airborne particulate matter (PM) can damage human health. Respiratory system, as a direct portal to contact with particulate matter, can be more susceptible to airborne particulates. Summarizing latest five-year epidemiological research, the present review is focused on the effects of PM on respiratory system health in different age groups. In detail, we investigated the harmful effect of PM, or its components on three common respiratory diseases, including lung function decline, chronic obstructive pulmonary disease (COPD) and asthma. The result showed that, to a certain degree, PM could induce the decline of lung function, the development and the exacerbation of COPD and asthma by oxidative stress and inflammatory reaction. And it may prompt that exposure to PM can be an improtant risk factor for the respiratory system health.

  13. 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.

  14. Ground Displacement Measurement of the 2013 Balochistan Earthquake with interferometric TerraSAR-X ScanSAR data

    NASA Astrophysics Data System (ADS)

    Yague-Martinez, N.; Fielding, E. J.; Haghshenas-Haghighi, M.; Cong, X.; Motagh, M.

    2014-12-01

    This presentation will address the 24 September 2013 Mw 7.7 Balochistan Earthquake in western Pakistan from the point of view of interferometric processing algorithms of wide-swath TerraSAR-X ScanSAR images. The algorithms are also valid for TOPS acquisition mode, the operational mode of the Sentinel-1A ESA satellite that was successfully launched in April 2014. Spectral properties of burst-mode data and an overview of the interferometric processing steps of burst-mode acquisitions, emphasizing the importance of the co-registration stage, will be provided. A co-registration approach based on incoherent cross-correlation will be presented and applied to seismic scenarios. Moreover geodynamic corrections due to differential atmospheric path delay and differential solid Earth tides are considered to achieve accuracy in the order of several centimeters. We previously derived a 3D displacement map using cross-correlation techniques applied to optical images from Landsat-8 satellite and TerraSAR-X ScanSAR amplitude images. The Landsat-8 cross-correlation measurements cover two horizontal directions, and the TerraSAR-X displacements include both horizontal along-track and slant-range (radar line-of-sight) measurements that are sensitive to vertical and horizontal deformation. It will be justified that the co-seismic displacement map from TerraSAR-X ScanSAR data may be contaminated by postseismic deformation due to the fact that the post-seismic acquisition took place one month after the main shock, confirmed in part by a TerraSAR-X stripmap interferogram (processed with conventional InSAR) covering part of the area starting on 27 September 2013. We have arranged the acquisition of a burst-synchronized stack of TerraSAR-X ScanSAR images over the affected area after the earthquake. It will be possible to apply interferometry to these data to measure the lower magnitude of the expected postseismic displacements. The processing of single interferograms will be discussed. A

  15. The application of satellite differential SAR interferometry-derived ground displacements in hydrogeology

    USGS Publications Warehouse

    Galloway, D.L.; Hoffmann, J.

    2007-01-01

    The application of satellite differential synthetic aperture radar (SAR) interferometry, principally coherent (InSAR) and to a lesser extent, persistent-scatterer (PSI) techniques to hydrogeologic studies has improved capabilities to map, monitor, analyze, and simulate groundwater flow, aquifer-system compaction and land subsidence. A number of investigations over the previous decade show how the spatially detailed images of ground displacements measured with InSAR have advanced hydrogeologic understanding, especially when a time series of images is used in conjunction with histories of changes in water levels and management practices. Important advances include: (1) identifying structural or lithostratigraphic boundaries (e.g. faults or transitional facies) of groundwater flow and deformation; (2) defining the material and hydraulic heterogeneity of deforming aquifer-systems; (3) estimating system properties (e.g. storage coefficients and hydraulic conductivities); and (4) constraining numerical models of groundwater flow, aquifer-system compaction, and land subsidence. As a component of an integrated approach to hydrogeologic monitoring and characterization of unconsolidated alluvial groundwater basins differential SAR interferometry contributes unique information that can facilitate improved management of groundwater resources. Future satellite SAR missions specifically designed for differential interferometry will enhance these contributions. ?? Springer-Verlag 2006.

  16. Statistical determination of whole-body average SARs in a 2 GHz whole-body exposure system for unrestrained pregnant and newborn rats

    NASA Astrophysics Data System (ADS)

    Wang, Jianqing; Wake, Kanako; Kawai, Hiroki; Watanabe, Soichi; Fujiwara, Osamu

    2012-01-01

    A 2 GHz whole-body exposure to rats over a multigeneration has been conducted as part of bio-effect research in Japan. In this study, the rats moved freely in the cage inside the exposure system. From observation of the activity of rats in the cage, we found that the rats do not stay in each position with uniform possibility. In order to determine the specific absorption rate (SAR) during the entire exposure period with high accuracy, we present a new approach to statistically determine the SAR level in an exposure system. First, we divided the rat cage in the exposure system into several small areas, and derived the fraction of time the rats spent in each small area based on the classification of the documentary photos of rat activity. Then, using the fraction of time spent in each small area as a weighting factor, we calculated the statistical characteristics of the whole-body average SAR for pregnant rats and young rats during the entire exposure period. As a result, this approach gave the statistical distribution as well as the corresponding mean value, median value and mode value for the whole-body SAR so that we can reasonably clarify the relationship between the exposure level and possible biological effect.

  17. A comparative study of SAR data compression schemes

    NASA Technical Reports Server (NTRS)

    Lambert-Nebout, C.; Besson, O.; Massonnet, D.; Rogron, B.

    1994-01-01

    The amount of data collected from spaceborne remote sensing has substantially increased in the last years. During same time period, the ability to store or transmit data has not increased as quickly. At this time, there is a growing interest in developing compression schemes that could provide both higher compression ratios and lower encoding/decoding errors. In the case of the spaceborne Synthetic Aperture Radar (SAR) earth observation system developed by the French Space Agency (CNES), the volume of data to be processed will exceed both the on-board storage capacities and the telecommunication link. The objective of this paper is twofold: to present various compression schemes adapted to SAR data; and to define a set of evaluation criteria and compare the algorithms on SAR data. In this paper, we review two classical methods of SAR data compression and propose novel approaches based on Fourier Transforms and spectrum coding.

  18. Structural Information Detection Based Filter for GF-3 SAR Images

    NASA Astrophysics Data System (ADS)

    Sun, Z.; Song, Y.

    2018-04-01

    GF-3 satellite with high resolution, large swath, multi-imaging mode, long service life and other characteristics, can achieve allweather and all day monitoring for global land and ocean. It has become the highest resolution satellite system in the world with the C-band multi-polarized synthetic aperture radar (SAR) satellite. However, due to the coherent imaging system, speckle appears in GF-3 SAR images, and it hinders the understanding and interpretation of images seriously. Therefore, the processing of SAR images has big challenges owing to the appearance of speckle. The high-resolution SAR images produced by the GF-3 satellite are rich in information and have obvious feature structures such as points, edges, lines and so on. The traditional filters such as Lee filter and Gamma MAP filter are not appropriate for the GF-3 SAR images since they ignore the structural information of images. In this paper, the structural information detection based filter is constructed, successively including the point target detection in the smallest window, the adaptive windowing method based on regional characteristics, and the most homogeneous sub-window selection. The despeckling experiments on GF-3 SAR images demonstrate that compared with the traditional filters, the proposed structural information detection based filter can well preserve the points, edges and lines as well as smooth the speckle more sufficiently.

  19. Pipelined digital SAR azimuth correlator using hybrid FFT-transversal filter

    NASA Technical Reports Server (NTRS)

    Wu, C.; Liu, K. Y. (Inventor)

    1984-01-01

    A synthetic aperture radar system (SAR) having a range correlator is provided with a hybrid azimuth correlator which utilizes a block-pipe-lined fast Fourier transform (FFT). The correlator has a predetermined FFT transform size with delay elements for delaying SAR range correlated data so as to embed in the Fourier transform operation a corner-turning function as the range correlated SAR data is converted from the time domain to a frequency domain. The azimuth correlator is comprised of a transversal filter to receive the SAR data in the frequency domain, a generator for range migration compensation and azimuth reference functions, and an azimuth reference multiplier for correlation of the SAR data. Following the transversal filter is a block-pipelined inverse FFT used to restore azimuth correlated data in the frequency domain to the time domain for imaging.

  20. Chimeric severe acute respiratory syndrome coronavirus (SARS-CoV) S glycoprotein and influenza matrix 1 efficiently form virus-like particles (VLPs) that protect mice against challenge with SARS-CoV

    PubMed Central

    Liu, Ye V.; Massare, Michael J.; Barnard, Dale L.; Kort, Thomas; Nathan, Margret; Wang, Lei; Smith, Gale

    2011-01-01

    SARS-CoV was the cause of the global pandemic in 2003 that infected over 8000 people in 8 months. Vaccines against SARS are still not available. We developed a novel method to produce high levels of a recombinant SARS virus-like particles (VLPs) vaccine containing the SARS spike (S) protein and the influenza M1 protein using the baculovirus insect cell expression system. These chimeric SARS VLPs have a similar size and morphology to the wild type SARS-CoV. We tested the immunogenicity and protective efficacy of purified chimeric SARS VLPs and full length SARS S protein vaccines in a mouse lethal challenge model. The SARS VLP vaccine, containing 0.8 μg of SARS S protein, completely protected mice from death when administered intramuscular (IM) or intranasal (IN) routes in the absence of an adjuvant. Likewise, the SARS VLP vaccine, containing 4 μg of S protein without adjuvant, reduced lung virus titer to below detectable level, protected mice from weight loss, and elicited a high level of neutralizing antibodies against SARS-CoV. Sf9 cell-produced full length purified SARS S protein was also an effective vaccine against SARS-CoV but only when co-administered IM with aluminum hydroxide. SARS-CoV VLPs are highly immunogenic and induce neutralizing antibodies and provide protection against lethal challenge. Sf9 cell-based VLP vaccines are a potential tool to provide protection against novel pandemic agents. PMID:21762752

  1. Millimeter wave radar system on a rotating platform for combined search and track functionality with SAR imaging

    NASA Astrophysics Data System (ADS)

    Aulenbacher, Uwe; Rech, Klaus; Sedlmeier, Johannes; Pratisto, Hans; Wellig, Peter

    2014-10-01

    Ground based millimeter wave radar sensors offer the potential for a weather-independent automatic ground surveillance at day and night, e.g. for camp protection applications. The basic principle and the experimental verification of a radar system concept is described, which by means of an extreme off-axis positioning of the antenna(s) combines azimuthal mechanical beam steering with the formation of a circular-arc shaped synthetic aperture (SA). In automatic ground surveillance the function of search and detection of moving ground targets is performed by means of the conventional mechanical scan mode. The rotated antenna structure designed as a small array with two or more RX antenna elements with simultaneous receiver chains allows to instantaneous track multiple moving targets (monopulse principle). The simultaneously operated SAR mode yields areal images of the distribution of stationary scatterers. For ground surveillance application this SAR mode is best suited for identifying possible threats by means of change detection. The feasibility of this concept was tested by means of an experimental radar system comprising of a 94 GHz (W band) FM-CW module with 1 GHz bandwidth and two RX antennas with parallel receiver channels, placed off-axis at a rotating platform. SAR mode and search/track mode were tested during an outdoor measurement campaign. The scenery of two persons walking along a road and partially through forest served as test for the capability to track multiple moving targets. For SAR mode verification an image of the area composed of roads, grassland, woodland and several man-made objects was reconstructed from the measured data.

  2. Data Analysis of Airborne Electromagnetic Bathymetry.

    DTIC Science & Technology

    1985-04-01

    7 AD-R 58 889 DATA ANALYSIS OF AIRBORNE ELECTROMAGNETIC BRTHYMETRY i/i (U) NAVAL OCEAN RESEARCH AND DEVELOPMENT ACTIVITY NSTL STRTION MS R ZOLLINGER...Naval Ocean Research and Development Activity NSTL, Mississippi 39529 NORDA Report 93 April 1985 AD-A158 809 - Data Analysis of Airborne Electromagnetic ...8217 - Foreword CI Airborne electromagnetic (AEM) systems have traditionally been used for detecting anomalous conductors in the

  3. 29. SAR2, VIEW TO NORTH WITH EXCITERS AT LEFT. SCE ...

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

    29. SAR-2, VIEW TO NORTH WITH EXCITERS AT LEFT. SCE negative no. 1043, photographed June 6, 1912. Photograph by G. Haven Bishop. - Santa Ana River Hydroelectric System, SAR-2 Powerhouse, Redlands, San Bernardino County, CA

  4. 31. SAR2, INTERIOR SHOWING SWITCHBOARD, OPERATOR'S DESK, AND TRANSFORMER BANK. ...

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

    31. SAR-2, INTERIOR SHOWING SWITCHBOARD, OPERATOR'S DESK, AND TRANSFORMER BANK. SCE negative no. 10327, November 1, 1923. Photograph by G. Haven Bishop. - Santa Ana River Hydroelectric System, SAR-2 Powerhouse, Redlands, San Bernardino County, CA

  5. 7. SOUTHEAST PENSTOCK ENTERING RECEIVER ON NORTHEAST SIDE OF SAR1, ...

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

    7. SOUTHEAST PENSTOCK ENTERING RECEIVER ON NORTHEAST SIDE OF SAR-1, ALSO SHOWING TURBINE SHUT OFF VALVES AND ISOLATION VALVE. VIEW TO WEST. - Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San Bernardino County, CA

  6. 36. SAR1 UNDER CONSTRUCTION, WITH WORKERS ATOP CRANE. EEC print ...

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

    36. SAR-1 UNDER CONSTRUCTION, WITH WORKERS ATOP CRANE. EEC print no. N-C-01-00031, no date. Photograph by Benjamin F. Pearson. - Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San Bernardino County, CA

  7. 33. SAR1, LOOKING DOWN CANYON OVER TAILRACE CONSTRUCTION. EEC print ...

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

    33. SAR-1, LOOKING DOWN CANYON OVER TAILRACE CONSTRUCTION. EEC print no. G-C-01-00269, no date. Photograph by Benjamin F. Pearson. - Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San Bernardino County, CA

  8. Flood extent and water level estimation from SAR using data-model integration

    NASA Astrophysics Data System (ADS)

    Ajadi, O. A.; Meyer, F. J.

    2017-12-01

    Synthetic Aperture Radar (SAR) images have long been recognized as a valuable data source for flood mapping. Compared to other sources, SAR's weather and illumination independence and large area coverage at high spatial resolution supports reliable, frequent, and detailed observations of developing flood events. Accordingly, SAR has the potential to greatly aid in the near real-time monitoring of natural hazards, such as flood detection, if combined with automated image processing. This research works towards increasing the reliability and temporal sampling of SAR-derived flood hazard information by integrating information from multiple SAR sensors and SAR modalities (images and Interferometric SAR (InSAR) coherence) and by combining SAR-derived change detection information with hydrologic and hydraulic flood forecast models. First, the combination of multi-temporal SAR intensity images and coherence information for generating flood extent maps is introduced. The application of least-squares estimation integrates flood information from multiple SAR sensors, thus increasing the temporal sampling. SAR-based flood extent information will be combined with a Digital Elevation Model (DEM) to reduce false alarms and to estimate water depth and flood volume. The SAR-based flood extent map is assimilated into the Hydrologic Engineering Center River Analysis System (Hec-RAS) model to aid in hydraulic model calibration. The developed technology is improving the accuracy of flood information by exploiting information from data and models. It also provides enhanced flood information to decision-makers supporting the response to flood extent and improving emergency relief efforts.

  9. Modeling and performance assessment in QinetiQ of EO and IR airborne reconnaissance systems

    NASA Astrophysics Data System (ADS)

    Williams, John W.; Potter, Gary E.

    2002-11-01

    QinetiQ are the technical authority responsible for specifying the performance requirements for the procurement of airborne reconnaissance systems, on behalf of the UK MoD. They are also responsible for acceptance of delivered systems, overseeing and verifying the installed system performance as predicted and then assessed by the contractor. Measures of functional capability are central to these activities. The conduct of these activities utilises the broad technical insight and wide range of analysis tools and models available within QinetiQ. This paper focuses on the tools, methods and models that are applicable to systems based on EO and IR sensors. The tools, methods and models are described, and representative output for systems that QinetiQ has been responsible for is presented. The principle capability applicable to EO and IR airborne reconnaissance systems is the STAR (Simulation Tools for Airborne Reconnaissance) suite of models. STAR generates predictions of performance measures such as GRD (Ground Resolved Distance) and GIQE (General Image Quality) NIIRS (National Imagery Interpretation Rating Scales). It also generates images representing sensor output, using the scene generation software CAMEO-SIM and the imaging sensor model EMERALD. The simulated image 'quality' is fully correlated with the predicted non-imaging performance measures. STAR also generates image and table data that is compliant with STANAG 7023, which may be used to test ground station functionality.

  10. 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.

  11. Studies of ice sheet hydrology using SAR

    NASA Technical Reports Server (NTRS)

    Bindschadler, R. A.; Vornberger, P. L.

    1989-01-01

    Analysis of SAR data of the Greenland ice sheet in summer and winter suggest the use of SAR to monitor the temporal hydrology of ice sheets. Comparisons of each SAR data set with summer Landsat TM imagery show an areal-positive correlation with summer SAR data and a negative correlation with winter SAR data. It is proposed that the summer SAR data are most sensitive to the variable concentrations of free water in the surface snow and that the winter SAR data indicate variations in snow grain size.

  12. Analysis of Wind and Sea State in SAR data of Hurricanes

    NASA Astrophysics Data System (ADS)

    Hoja, D.; Schulz-Stellenfleth, J.; Lehner, S.; Horstmann, J.

    2003-04-01

    Spaceborne synthetic aperture radar (SAR) is still the only instrument providing directional ocean wave and in addition surface wind information on a global and continuous basis. Operating in ASAR wave mode ENVISAT, launched in 2002, provides 10 km x 5 km SAR images every 100 km along the orbit. These SAR data continue and expand the SAR era of the European Remote Sensing satellites ERS-1 and ERS-2, which have acquired similar SAR data since 1991 on a global basis. To not only use the official ERS SAR wave mode product, which consists only of the SAR image power spectrum, but also the full SAR image information a subset of 27 days globally distributed ERS-2 SAR raw data were processed to single look complex SAR imagettes using the BSAR processor developed at the German Aerospace Center. These data have the same format as the official ESA product for ENVISAT ASAR wave mode data. This subset of 34,000 ERS-2 SAR imagettes was used to develop and validate algorithms for wind and wave retrieval, which are also applicable to ENVISAT ASAR wave mode data. The time frame of the dataset covers several tropical cyclones in the Atlantic Ocean of which hurricane Fran has been investigated in detail together with additional data available from scatterometers, buoys and weather centers. Hurricane Fran was active from August 23 to September 8, 1996. During this time, hurricane Fran developed near the African coast and progressed over the North Atlantic Ocean. Landfall occurred on September 5, 1996 at the coast of North Carolina, USA. Fran was part of a whole series of tropical cyclones travelling about the same course in a short time. The wind is extracted from SAR imagery and compared to results of the numerical model output provided by the European Center for Medium-Range Weather Forecast (ECMWF) and co-located ERS-2 scatterometer measurements. The Swell and wind sea systems generated by the tropical cyclones are measured using SAR cross spectra and a newly developed

  13. Integrating SAR and derived products into operational volcano monitoring and decision support systems

    NASA Astrophysics Data System (ADS)

    Meyer, F. J.; McAlpin, D. B.; Gong, W.; Ajadi, O.; Arko, S.; Webley, P. W.; Dehn, J.

    2015-02-01

    Remote sensing plays a critical role in operational volcano monitoring due to the often remote locations of volcanic systems and the large spatial extent of potential eruption pre-cursor signals. Despite the all-weather capabilities of radar remote sensing and its high performance in monitoring of change, the contribution of radar data to operational monitoring activities has been limited in the past. This is largely due to: (1) the high costs associated with radar data; (2) traditionally slow data processing and delivery procedures; and (3) the limited temporal sampling provided by spaceborne radars. With this paper, we present new data processing and data integration techniques that mitigate some of these limitations and allow for a meaningful integration of radar data into operational volcano monitoring decision support systems. Specifically, we present fast data access procedures as well as new approaches to multi-track processing that improve near real-time data access and temporal sampling of volcanic systems with SAR data. We introduce phase-based (coherent) and amplitude-based (incoherent) change detection procedures that are able to extract dense time series of hazard information from these data. For a demonstration, we present an integration of our processing system with an operational volcano monitoring system that was developed for use by the Alaska Volcano Observatory (AVO). Through an application to a historic eruption, we show that the integration of SAR into systems such as AVO can significantly improve the ability of operational systems to detect eruptive precursors. Therefore, the developed technology is expected to improve operational hazard detection, alerting, and management capabilities.

  14. Nepal and Papua Airborne Gravity Surveys

    NASA Astrophysics Data System (ADS)

    Olesen, A. V.; Forsberg, R.; Kasenda, F.; Einarsson, I.; Manandhar, N.

    2011-12-01

    Airborne gravimetry offers a fast and economic way to cover vast areas and it allows access to otherwise difficult accessible areas like mountains, jungles and the near coastal zone. It has the potential to deliver high resolution and bias free data that may bridge the spectral gap between global satellite gravity models and the high resolution gravity information embedded in digital terrain models. DTU Space has for more than a decade done airborne gravity surveys in many parts of the world. Most surveys were done with a LaCoste & Romberg S-meter updated for airborne use. This instrument has proven to deliver near bias free data when properly processed. A Chekan AM gravimeter was recently added to the airborne gravity mapping system and will potentially enhance the spatial resolution and the robustness of the system. This paper will focus on results from two recent surveys over Nepal, flown in December 2010, and over Papua (eastern Indonesia), flown in May and June 2011. Both surveys were flown with the new double gravimeter setup and initial assessment of system performance indicates improved spatial resolution compared to the single gravimeter system. Comparison to EGM08 and to the most recent GOCE models highlights the impact of the new airborne gravity data in both cases. A newly computed geoid model for Nepal based on the airborne data allows for a more precise definition of the height of Mt. Everest in a global height system. This geoid model suggests that the height of Mt. Everest should be increased by approximately 1 meter. The paper will also briefly discuss system setup and will highlight a few essential processing steps that ensure that bias problems are minimized and spatial resolution enhanced.

  15. 26. SAR2, GENERAL VIEW FROM WEST SHOWING DAMAGE FROM 1938 ...

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

    26. SAR-2, GENERAL VIEW FROM WEST SHOWING DAMAGE FROM 1938 FLOOD. SCE negative no. 20949, March 30, 1938. Photograph by G. Haven Bishop. - Santa Ana River Hydroelectric System, SAR-2 Powerhouse, Redlands, San Bernardino County, CA

  16. 35. SAR1 UNDER CONSTRUCTION, SHOWING TAILRACE AREA AND SCAFFOLDING. EEC ...

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

    35. SAR-1 UNDER CONSTRUCTION, SHOWING TAILRACE AREA AND SCAFFOLDING. EEC print no. N-C-01-00028, no date. Photograph by Benjamin F. Pearson. - Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San Bernardino County, CA

  17. Estimation of Bridge Height over Water from Polarimetric SAR Image Data Using Mapping and Projection Algorithm and De-Orientation Theory

    NASA Astrophysics Data System (ADS)

    Wang, Haipeng; Xu, Feng; Jin, Ya-Qiu; Ouchi, Kazuo

    An inversion method of bridge height over water by polarimetric synthetic aperture radar (SAR) is developed. A geometric ray description to illustrate scattering mechanism of a bridge over water surface is identified by polarimetric image analysis. Using the mapping and projecting algorithm, a polarimetric SAR image of a bridge model is first simulated and shows that scattering from a bridge over water can be identified by three strip lines corresponding to single-, double-, and triple-order scattering, respectively. A set of polarimetric parameters based on the de-orientation theory is applied to analysis of three types scattering, and the thinning-clustering algorithm and Hough transform are then employed to locate the image positions of these strip lines. These lines are used to invert the bridge height. Fully polarimetric image data of airborne Pi-SAR at X-band are applied to inversion of the height and width of the Naruto Bridge in Japan. Based on the same principle, this approach is also applicable to spaceborne ALOSPALSAR single-polarization data of the Eastern Ocean Bridge in China. The results show good feasibility to realize the bridge height inversion.

  18. Estimation of Separation Buffers for Wind-Prediction Error in an Airborne Separation Assistance System

    NASA Technical Reports Server (NTRS)

    Consiglio, Maria C.; Hoadley, Sherwood T.; Allen, B. Danette

    2009-01-01

    Wind prediction errors are known to affect the performance of automated air traffic management tools that rely on aircraft trajectory predictions. In particular, automated separation assurance tools, planned as part of the NextGen concept of operations, must be designed to account and compensate for the impact of wind prediction errors and other system uncertainties. In this paper we describe a high fidelity batch simulation study designed to estimate the separation distance required to compensate for the effects of wind-prediction errors throughout increasing traffic density on an airborne separation assistance system. These experimental runs are part of the Safety Performance of Airborne Separation experiment suite that examines the safety implications of prediction errors and system uncertainties on airborne separation assurance systems. In this experiment, wind-prediction errors were varied between zero and forty knots while traffic density was increased several times current traffic levels. In order to accurately measure the full unmitigated impact of wind-prediction errors, no uncertainty buffers were added to the separation minima. The goal of the study was to measure the impact of wind-prediction errors in order to estimate the additional separation buffers necessary to preserve separation and to provide a baseline for future analyses. Buffer estimations from this study will be used and verified in upcoming safety evaluation experiments under similar simulation conditions. Results suggest that the strategic airborne separation functions exercised in this experiment can sustain wind prediction errors up to 40kts at current day air traffic density with no additional separation distance buffer and at eight times the current day with no more than a 60% increase in separation distance buffer.

  19. 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.

  20. 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.

  1. Airborne laser-diode-array illuminator assessment for the night vision's airborne mine-detection arid test

    NASA Astrophysics Data System (ADS)

    Stetson, Suzanne; Weber, Hadley; Crosby, Frank J.; Tinsley, Kenneth; Kloess, Edmund; Nevis, Andrew J.; Holloway, John H., Jr.; Witherspoon, Ned H.

    2004-09-01

    The Airborne Littoral Reconnaissance Technologies (ALRT) project has developed and tested a nighttime operational minefield detection capability using commercial off-the-shelf high-power Laser Diode Arrays (LDAs). The Coastal System Station"s ALRT project, under funding from the Office of Naval Research (ONR), has been designing, developing, integrating, and testing commercial arrays using a Cessna airborne platform over the last several years. This has led to the development of the Airborne Laser Diode Array Illuminator wide field-of-view (ALDAI-W) imaging test bed system. The ALRT project tested ALDAI-W at the Army"s Night Vision Lab"s Airborne Mine Detection Arid Test. By participating in Night Vision"s test, ALRT was able to collect initial prototype nighttime operational data using ALDAI-W, showing impressive results and pioneering the way for final test bed demonstration conducted in September 2003. This paper describes the ALDAI-W Arid Test and results, along with processing steps used to generate imagery.

  2. Ground-Level Digital Terrain Model (DTM) Construction from Tandem-X InSAR Data and Worldview Stereo-Photogrammetric Images

    NASA Technical Reports Server (NTRS)

    Lee, Seung-Kuk; Fatoyinbo, Temilola; Lagomasino, David; Osmanoglu, Batuhan; Feliciano, Emanuelle

    2016-01-01

    The ground-level digital elevation model (DEM) or digital terrain model (DTM) information are invaluable for environmental modeling, such as water dynamics in forests, canopy height, forest biomass, carbon estimation, etc. We propose to extract the DTM over forested areas from the combination of interferometric complex coherence from single-pass TanDEM-X (TDX) data at HH polarization and Digital Surface Model (DSM) derived from high-resolution WorldView (WV) image pair by means of random volume over ground (RVoG) model. The RVoG model is a widely and successfully used model for polarimetric SAR interferometry (Pol-InSAR) technique for vertical forest structure parameter retrieval [1][2][3][4]. The ground-level DEM have been obtained by complex volume decorrelation in the RVoG model with the DSM using stereo-photogrammetric technique. Finally, the airborne lidar data were used to validate the ground-level DEM and forest canopy height results.

  3. Quantum-SAR Extension of the Spectral-SAR Algorithm. Application to Polyphenolic Anticancer Bioactivity

    PubMed Central

    Putz, Mihai V.; Putz, Ana-Maria; Lazea, Marius; Ienciu, Luciana; Chiriac, Adrian

    2009-01-01

    Aiming to assess the role of individual molecular structures in the molecular mechanism of ligand-receptor interaction correlation analysis, the recent Spectral-SAR approach is employed to introduce the Quantum-SAR (QuaSAR) “wave” and “conversion factor” in terms of difference between inter-endpoint inter-molecular activities for a given set of compounds; this may account for inter-conversion (metabolization) of molecular (concentration) effects while indicating the structural (quantum) based influential/detrimental role on bio-/eco- effect in a causal manner rather than by simple inspection of measured values; the introduced QuaSAR method is then illustrated for a study of the activity of a series of flavonoids on breast cancer resistance protein. PMID:19399244

  4. Altered Lipid Metabolism in Recovered SARS Patients Twelve Years after Infection.

    PubMed

    Wu, Qi; Zhou, Lina; Sun, Xin; Yan, Zhongfang; Hu, Chunxiu; Wu, Junping; Xu, Long; Li, Xue; Liu, Huiling; Yin, Peiyuan; Li, Kuan; Zhao, Jieyu; Li, Yanli; Wang, Xiaolin; Li, Yu; Zhang, Qiuyang; Xu, Guowang; Chen, Huaiyong

    2017-08-22

    Severe acute respiratory syndrome-coronavirus (SARS-CoV) and SARS-like coronavirus are a potential threat to global health. However, reviews of the long-term effects of clinical treatments in SARS patients are lacking. Here a total of 25 recovered SARS patients were recruited 12 years after infection. Clinical questionnaire responses and examination findings indicated that the patients had experienced various diseases, including lung susceptibility to infections, tumors, cardiovascular disorders, and abnormal glucose metabolism. As compared to healthy controls, metabolomic analyses identified significant differences in the serum metabolomes of SARS survivors. The most significant metabolic disruptions were the comprehensive increase of phosphatidylinositol and lysophospha tidylinositol levels in recovered SARS patients, which coincided with the effect of methylprednisolone administration investigated further in the steroid treated non-SARS patients with severe pneumonia. These results suggested that high-dose pulses of methylprednisolone might cause long-term systemic damage associated with serum metabolic alterations. The present study provided information for an improved understanding of coronavirus-associated pathologies, which might permit further optimization of clinical treatments.

  5. 12. OVERVIEW FROM FORMER RESIDENTIAL AREA NORTH OF SAR2, SHOWING ...

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

    12. OVERVIEW FROM FORMER RESIDENTIAL AREA NORTH OF SAR-2, SHOWING TRAIL UP TO FOREBAY, RETAINING WALL, PEPPER TREES, AND SAR-2 IN DISTANCE. VIEW TO SOUTH-SOUTHEAST. - Santa Ana River Hydroelectric System, Redlands, San Bernardino County, CA

  6. 1. SAR1, SOUTHEAST AND SOUTHWEST ELEVATIONS, WITH SWITCH RACK AT ...

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

    1. SAR-1, SOUTHEAST AND SOUTHWEST ELEVATIONS, WITH SWITCH RACK AT LEFT, AND SANTA ANA WELL #1 AND STONE RETAINING WALLS AT RIGHT. VIEW TO NORTH. - Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San Bernardino County, CA

  7. 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.

  8. An airborne thematic thermal infrared and electro-optical imaging system

    NASA Astrophysics Data System (ADS)

    Sun, Xiuhong; Shu, Peter

    2011-08-01

    This paper describes an advanced Airborne Thematic Thermal InfraRed and Electro-Optical Imaging System (ATTIREOIS) and its potential applications. ATTIREOIS sensor payload consists of two sets of advanced Focal Plane Arrays (FPAs) - a broadband Thermal InfraRed Sensor (TIRS) and a four (4) band Multispectral Electro-Optical Sensor (MEOS) to approximate Landsat ETM+ bands 1,2,3,4, and 6, and LDCM bands 2,3,4,5, and 10+11. The airborne TIRS is 3-axis stabilized payload capable of providing 3D photogrammetric images with a 1,850 pixel swathwidth via pushbroom operation. MEOS has a total of 116 million simultaneous sensor counts capable of providing 3 cm spatial resolution multispectral orthophotos for continuous airborne mapping. ATTIREOIS is a complete standalone and easy-to-use portable imaging instrument for light aerial vehicle deployment. Its miniaturized backend data system operates all ATTIREOIS imaging sensor components, an INS/GPS, and an e-Gimbal™ Control Electronic Unit (ECU) with a data throughput of 300 Megabytes/sec. The backend provides advanced onboard processing, performing autonomous raw sensor imagery development, TIRS image track-recovery reconstruction, LWIR/VNIR multi-band co-registration, and photogrammetric image processing. With geometric optics and boresight calibrations, the ATTIREOIS data products are directly georeferenced with an accuracy of approximately one meter. A prototype ATTIREOIS has been configured. Its sample LWIR/EO image data will be presented. Potential applications of ATTIREOIS include: 1) Providing timely and cost-effective, precisely and directly georeferenced surface emissive and solar reflective LWIR/VNIR multispectral images via a private Google Earth Globe to enhance NASA's Earth science research capabilities; and 2) Underflight satellites to support satellite measurement calibration and validation observations.

  9. 37. SAR2, SHOWING OIL CIRCUIT BREAKERS (ABOVE) AND GENERATOR FIELD ...

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

    37. SAR-2, SHOWING OIL CIRCUIT BREAKERS (ABOVE) AND GENERATOR FIELD COIL CONTROL RHEOSTATS (BELOW). SCE negative no. 10331, November 1, 1923. Photograph by G. Haven Bishop. - Santa Ana River Hydroelectric System, SAR-2 Powerhouse, Redlands, San Bernardino County, CA

  10. 46. LONGITUDINAL SECTION POWER HOUSE S.A.R. NO. 2, EDISON ...

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

    46. LONGITUDINAL SECTION - POWER HOUSE S.A.R. NO. 2, EDISON PROJECT, APR. 30, 1945. SCE drawing no. 523198 (sheet no. 8; for filing with Federal Power Commission). - Santa Ana River Hydroelectric System, SAR-2 Powerhouse, Redlands, San Bernardino County, CA

  11. The replication of a mouse adapted SARS-CoV in a mouse cell line stably expressing the murine SARS-CoV receptor mACE2 efficiently induces the expression of proinflammatory cytokines

    PubMed Central

    Regla-Nava, Jose A.; Jimenez-Guardeño, Jose M.; Nieto-Torres, Jose L.; Gallagher, Thomas M.; Enjuanes, Luis; DeDiego, Marta L.

    2013-01-01

    Infection of conventional mice with a mouse adapted (MA15) severe acute respiratory syndrome (SARS) coronavirus (CoV) reproduces many aspects of human SARS such as pathological changes in lung, viremia, neutrophilia, and lethality. However, established mouse cell lines highly susceptible to mouse-adapted SARS-CoV infection are not available. In this work, efficiently transfectable mouse cell lines stably expressing the murine SARS-CoV receptor angiotensin converting enzyme 2 (ACE2) have been generated. These cells yielded high SARS-CoV-MA15 titers and also served as excellent tools for plaque assays. In addition, in these cell lines, SARS-CoV-MA15 induced the expression of proinflammatory cytokines and IFN-β, mimicking what has been observed in experimental animal models infected with SARS-CoV and SARS patients. These cell lines are valuable tools to perform in vitro studies in a mouse cell system that reflects the species used for in vivo studies of SARS-CoV-MA15 pathogenesis. PMID:23911968

  12. Operational Use of Civil Space-Based Synthetic Aperture Radar (SAR)

    NASA Technical Reports Server (NTRS)

    Montgomery, Donald R. (Editor)

    1996-01-01

    Synthetic Aperture Radar (SAR) is a remote-sensing technology which uses the motion of the aircraft or spacecraft carrying the radar to synthesize an antenna aperture larger than the physical antenna to yield a high-spatial resolution imaging capability. SAR systems can thus obtain high-spatial resolution geophysical measurements of the Earth over wide surface areas, under all-weather, day/night conditions. This report was prepared to document the results of a six-month study by an Ad Hoc Interagency Working Group on the Operational Use of Civil (i.e., non-military) Space-based Synthetic Aperture Radar (SAR). The Assistant Administrator of NOAA for Satellite and Information Services convened this working group and chaired three meetings of the group over a six-month period. This action was taken in response to a request by the Associate Administrator of NASA for Mission to Planet Earth for an assessment of operational applications of SAR to be accomplished in parallel with a separate study requested of the Committee on Earth Studies of the Space Studies Board of the National Research Council on the scientific results of SAR research missions. The representatives of participating agencies are listed following the Preface. There was no formal charter for the working group or long term plans for future meetings. However, the working group may be reconstituted in the future as a coordination body for multiagency use of operational SAR systems.

  13. 52. SAR1, OPERATOR WORKING GOVERNOR. EEC print no. GC0100390, no ...

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

    52. SAR-1, OPERATOR WORKING GOVERNOR. EEC print no. G-C-01-00390, no date. Photograph by Benjamin F. Pearson. - Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San Bernardino County, CA

  14. SU-F-I-27: Measurement of SAR and Temperature Elevation During MRI Scans

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

    Seo, Y

    Purpose: The poor reliability and repeatability of the manufacturer-reported SAR values on clinical MRI systems have been acknowledged. The purpose of this study is to not only measure SAR values, but also RF-induced temperature elevation at 1.5 and 3T MRI systems. Methods: SAR measurement experiment was performed at 1.5 and 3T. Three MRI RF sequences (T1w TSE, T1w inversion recovery, and T2w TSE) with imaging parameters were selected. A hydroxyl-ethylcelluose (HEC) gelled saline phantom mimicking human body tissue was made. Human torso phantom were constructed, based on Korean adult standard anthropometric reference data (Fig.1). FDTD method was utilized to calculatemore » the SAR distribution using Sim4Life software. Based on the results of the simulation, 4 electrical field (E-field) sensors were located inside the phantom. 55 Fiber Bragg Grating (FBG) temperature sensors (27 sensors in upper and lower cover lids, and one sensor located in the center as a reference) were located inside the phantom to measure temperature change during MRI scan (Fig.2). Results: Simulation shows that SAR value is 0.4 W/kg in the periphery and 0.001 W/kg in the center (Fig.2). One 1.5T and one of two 3T MRI systems represent that the measured SAR values were lower than MRI scanner-reported SAR values. However, the other 3T MRI scanner shows that the averaged SAR values measured by probe 2, 3, and 4 are 6.83, 7.59, and 6.01 W/kg, compared to MRI scanner-reported whole body SAR value (<1.5 W/kg) for T2w TSE (Table 1). The temperature elevation measured by FBG sensors is 5.2°C in the lateral shoulder, 5.1°C in the underarm, 4.7°C in the anterior axilla, 4.8°C in the posterior axilla, and 4.8°C in the lateral waist for T2w TSE (Fig.3). Conclusion: It is essential to assess the safety of MRI system for patient by measuring accurate SAR deposited in the body during clinical MRI.« less

  15. ARF1 and SAR1 GTPases in Endomembrane Trafficking in Plants

    PubMed Central

    Cevher-Keskin, Birsen

    2013-01-01

    Small GTPases largely control membrane traffic, which is essential for the survival of all eukaryotes. Among the small GTP-binding proteins, ARF1 (ADP-ribosylation factor 1) and SAR1 (Secretion-Associated RAS super family 1) are commonly conserved among all eukaryotes with respect to both their functional and sequential characteristics. The ARF1 and SAR1 GTP-binding proteins are involved in the formation and budding of vesicles throughout plant endomembrane systems. ARF1 has been shown to play a critical role in COPI (Coat Protein Complex I)-mediated retrograde trafficking in eukaryotic systems, whereas SAR1 GTPases are involved in intracellular COPII-mediated protein trafficking from the ER to the Golgi apparatus. This review offers a summary of vesicular trafficking with an emphasis on the ARF1 and SAR1 expression patterns at early growth stages and in the de-etiolation process. PMID:24013371

  16. 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.

  17. Completing the gaps in Kilauea's Father's Day InSAR displacement signature with ScanSAR

    NASA Astrophysics Data System (ADS)

    Bertran Ortiz, A.; Pepe, A.; Lanari, R.; Lundgren, P.; Rosen, P. A.

    2009-12-01

    Currently there are gaps in the known displacement signature obtained with InSAR at Kilauea between 2002 and 2009. InSAR data can be richer than GPS because of denser spatial cover. However, to better model rapidly varying and non-steady geophysical events InSAR is limited because of its less dense time observations of the area under study. The ScanSAR mode currently available in several satellites mitigates this effect because the satellite may illuminate a given area more than once within an orbit cycle. The Kilauea displacement graph below from Instituto per Il Rilevamento Electromagnetico dell'Ambiente (IREA) is a cut in space of the displacement signature obtained from a time series of several stripmap-to-stripmap interferograms. It shows that critical information is missing, especially between 2006 and 2007. The displacement is expected to be non-linear judging from the 2007-2008 displacement signature, thus simple interpolation would not suffice. The gap can be filled by incorporating Envisat stripmap-to-ScanSAR interferograms available during that time period. We propose leveraging JPL's new ROI-PAC ScanSAR module to create stripmap-to-ScanSAR interferograms. The new interferograms will be added to the stripmap ones in order to extend the existing stripmap time series generated by using the Small BAseline Subset (SBAS) technique. At AGU we will present denser graphs that better capture Kilauea's displacement between 2003 and 2009.

  18. Relationships between autofocus methods for SAR and self-survey techniques for SONAR. [Synthetic Aperture Radar (SAR)

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

    Wahl, D.E.; Jakowatz, C.V. Jr.; Ghiglia, D.C.

    1991-01-01

    Autofocus methods in SAR and self-survey techniques in SONAR have a common mathematical basis in that they both involve estimation and correction of phase errors introduced by sensor position uncertainties. Time delay estimation and correlation methods have been shown to be effective in solving the self-survey problem for towed SONAR arrays. Since it can be shown that platform motion errors introduce similar time-delay estimation problems in SAR imaging, the question arises as to whether such techniques could be effectively employed for autofocus of SAR imagery. With a simple mathematical model for motion errors in SAR, we will show why suchmore » correlation/time-delay techniques are not nearly as effective as established SAR autofocus algorithms such as phase gradient autofocus or sub-aperture based methods. This analysis forms an important bridge between signal processing methodologies for SAR and SONAR. 5 refs., 4 figs.« less

  19. Applications of the EOS SAR to monitoring global change

    NASA Technical Reports Server (NTRS)

    Schier, Marguerite; Way, Jobea; Holt, Benjamin

    1991-01-01

    The SAR employed by NASA's Earth Observing System (EOS) is a multifrequency multipolarization radar which can conduct global monitoring of geophysical and biophysical parameters. The present discussion of the EOS SAR's role in global monitoring emphasizes geophysical product variables applicable to global hydrologic, biogeochemical, and energy cycle models. EOS SAR products encompass biomass, wetland areas, and phenologic and environmental states, in the field of ecosystem dynamics; soil moisture, snow moisture and extent, and glacier and ice sheet extent and velocity, in hydrologic cycle studies; surface-wave fields and sea ice properties, in ocean/atmosphere circulation; and the topography, erosion, and land forms of the solid earth.

  20. SAR antenna calibration techniques

    NASA Technical Reports Server (NTRS)

    Carver, K. R.; Newell, A. C.

    1978-01-01

    Calibration of SAR antennas requires a measurement of gain, elevation and azimuth pattern shape, boresight error, cross-polarization levels, and phase vs. angle and frequency. For spaceborne SAR antennas of SEASAT size operating at C-band or higher, some of these measurements can become extremely difficult using conventional far-field antenna test ranges. Near-field scanning techniques offer an alternative approach and for C-band or X-band SARs, give much improved accuracy and precision as compared to that obtainable with a far-field approach.

  1. Airborne Lidar Surface Topography (LIST) Simulator

    NASA Technical Reports Server (NTRS)

    Yu, Anthony W.; Krainak, Michael A.; Harding, David J.; Abshire, James B.; Sun, Xiaoli; Cavanaugh, John; Valett, Susan; Ramos-Izquierdo, Luis; Winkert, Tom; Plants, Michael; hide

    2011-01-01

    In this paper we will discuss our development effort of an airborne instrument as a pathfinder for the Lidar Surface Technology (LIST) mission. This paper will discuss the system approach, enabling technologies, instrument concept and performance of the Airborne LIST Simulator (A-LISTS).

  2. Temporal Coherence as an Estimate of Decorrelation Time of SAR Interferometric Measurements

    NASA Astrophysics Data System (ADS)

    Foumelis, Michael

    2014-05-01

    Following a plethora of validations and demonstrations Interferometric SAR (InSAR) has been established as a mature space geodetic technique for providing valuable insights for various phenomena related to geohazards. One of the main advantages of space borne SAR systems with respect to GNSS is the continuous spatial coverage. However, the impact of temporal decorrelation especially in repeat-pass interferometry has been observed during the historical development of InSAR applications. Interferometric coherence is considered as the expression of temporal decorrelation. It is understood that interferometric coherence decreases with time between SAR acquisitions because of changes in surface reflectivity, reducing the accuracy and spatial coverage of SAR phase measurements. This is an intrinsic characteristic of the design of SAR systems that has a significant contribution at longer time scales. Since the majority of geohazards rely on long term observation scenarios, the effect of temporal decorrelation is evident as coherence becomes dominated by temporal changes. Although in the past there was not sufficient amount of SAR data to extract robust statistical metrics, in the present study it is demonstrated that tailored analysis of interferometric coherence by exploiting the large archive of SAR data available by the European Space Agency (ESA), enables the accurate quantification of temporal decorrelation. A methodology to translate the observed rate of coherence loss into decorrelation times over a volcanic landscape is the subject treated in this study. Specifically, a sensitivity analysis based on a large data stack of interferometric pairs in order to quantitatively estimate at a pixel level the time beyond which each interferometric phase becomes practically unusable is presented. The estimation and mapping of the spatial distribution of the temporal decorrelation times in an area without a necessary a priori knowledge of its surface characteristics is a

  3. 29. OVERVIEW OF SAR3 COMPLEX, LOOKING NORTHEAST. FROM LEFT TO ...

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

    29. OVERVIEW OF SAR-3 COMPLEX, LOOKING NORTHEAST. FROM LEFT TO RIGHT, THE STRUCTURES ARE THE SAR-3 POWERHOUSE, SWITCHRACK, OFFICE (IN BACKGROUND), WAREHOUSE, CARPENTER SHOP, MAINTENANCE YARD, STORAGE BUILDING, AND STORAGE GARAGE (IN BACKGROUND). - Santa Ana River Hydroelectric System, Redlands, San Bernardino County, CA

  4. Interferometric synthetic aperture radar (InSAR)—its past, present and future

    USGS Publications Warehouse

    Lu, Zhong; Kwoun, Oh-Ig; Rykhus, R.P.

    2007-01-01

    Very simply, interferometric synthetic aperture radar (InSAR) involves the use of two or more synthetic aperture radar (SAR) images of the same area to extract landscape topography and its deformation patterns. A SAR system transmits electromagnetic waves at a wavelength that can range from a few millimeters to tens of centimeters and therefore can operate during day and night under all-weather conditions. Using SAR processing technique (Curlander and McDonough, 1991), both the intensity and phase of the reflected (or backscattered) radar signal of each ground resolution element (a few meters to tens of meters) can be calculated in the form of a complex-valued SAR image that represents the reflectivity of the ground surface. The amplitude or intensity of the SAR image is determined primarily by terrain slope, surface roughness, and dielectric constants, whereas the phase of the SAR image is determined primarily by the distance between the satellite antenna and the ground targets. InSAR imaging utilizes the interaction of electromagnetic waves, referred to as interference, to measure precise distances between the satellite antenna and ground resolution elements to derive landscape topography and its subtle change in elevation.

  5. Technical standing order : airborne supplemental navigation equipment using the global positioning system (GPS)

    DOT National Transportation Integrated Search

    2001-01-01

    This technical standard order (TSO) prescribes the minimum performance standard that airborne supplemental area navigation equipment using the global positioning system (GPS) must meet in order to be identified with the applicable TSO marking. Airbor...

  6. Compact SAR and Small Satellite Solutions for Earth Observation

    NASA Astrophysics Data System (ADS)

    LaRosa, M.; L'Abbate, M.

    2016-12-01

    Requirements for near and short term mission applications (Observation and Reconnaissance, SIGINT, Early Warning, Meteorology,..) are increasingly calling for spacecraft operational responsiveness, flexible configuration, lower cost satellite constellations and flying formations, to improve both the temporal performance of observation systems (revisit, response time) and the remote sensing techniques (distributed sensors, arrays, cooperative sensors). In answer to these users' needs, leading actors in Space Systems for EO are involved in development of Small and Microsatellites solutions. Thales Alenia Space (TAS) has started the "COMPACT-SAR" project to develop a SAR satellite characterized by low cost and reduced mass while providing, at the same time, high image quality in terms of resolution, swath size, and radiometric performance. Compact SAR will embark a X-band SAR based on a deployable reflector antenna fed by an active phased array feed. This concept allows high performance, providing capability of electronic beam steering both in azimuth and elevation planes, improving operational performance over a purely mechanically steered SAR system. Instrument provides both STRIPMAP and SPOTLIGHT modes, and thanks to very high gain antenna, can also provide a real maritime surveillance mode based on a patented Low PRF radar mode. Further developments are in progress considering missions based on Microsatellites technology, which can provide effective solutions for different user needs, such as Operational responsiveness, low cost constellations, distributed observation concept, flying formations, and can be conceived for applications in the field of Observation, Atmosphere sensing, Intelligence, Surveillance, Reconnaissance (ISR), Signal Intelligence. To satisfy these requirements, flexibility of small platforms is a key driver and especially new miniaturization technologies able to optimize the performance. An overview new micros-satellite (based on NIMBUS

  7. Exploring cloud and big data components for SAR archiving and analysis

    NASA Astrophysics Data System (ADS)

    Baker, S.; Crosby, C. J.; Meertens, C.; Phillips, D.

    2017-12-01

    Under the Geodesy Advancing Geoscience and EarthScope (GAGE) NSF Cooperative Agreement, UNAVCO has seen the volume of the SAR Data Archive grow at a substantial rate, from 2 TB in Y1 and 5 TB in Y2 to 41 TB in Y3 primarily due to WInSAR PI proposal management of ALOS-­2/JAXA (Japan Aerospace Exploration Agency) data and to a lesser extent Supersites and other data collections. JAXA provides a fixed number of scenes per year for each PI, and some data files are 50­-60GB each, which accounts for the large volume of data. In total, over 100TB of SAR data are in the WInSAR/UNAVCO archive and a large portion of these are available unrestricted for WInSAR members. In addition to the existing data, newer data streams from the Sentinel-1 and NISAR missions will require efficient processing pipelines and easily scalable infrastructure to handle processed results. With these growing data sizes and space concerns, the SAR archive operations migrated to the Texas Advanced Computing Center (TACC) via an NSF XSEDE proposal in spring 2017. Data are stored on an HPC system while data operations are running on Jetstream virtual machines within the same datacenter. In addition to the production data operations, testing was done in early 2017 with container based InSAR processing analysis using JupyterHub and Docker images deployed on a VM cluster on Jetstream. The JupyterHub environment is well suited for short courses and other training opportunities for the community such as labs for university courses on InSAR. UNAVCO is also exploring new processing methodologies using DC/OS (the datacenter operating system) for batch and stream processing workflows and time series analysis with Big Data open source components like the Spark, Mesos, Akka, Cassandra, Kafka (SMACK) stack. The comparison of the different methodologies will provide insight into the pros and cons for each and help the SAR community with decisions about infrastructure and software requirements to meet their research

  8. The replication of a mouse adapted SARS-CoV in a mouse cell line stably expressing the murine SARS-CoV receptor mACE2 efficiently induces the expression of proinflammatory cytokines.

    PubMed

    Regla-Nava, Jose A; Jimenez-Guardeño, Jose M; Nieto-Torres, Jose L; Gallagher, Thomas M; Enjuanes, Luis; DeDiego, Marta L

    2013-11-01

    Infection of conventional mice with a mouse adapted (MA15) severe acute respiratory syndrome (SARS) coronavirus (CoV) reproduces many aspects of human SARS such as pathological changes in lung, viremia, neutrophilia, and lethality. However, established mouse cell lines highly susceptible to mouse-adapted SARS-CoV infection are not available. In this work, efficiently transfectable mouse cell lines stably expressing the murine SARS-CoV receptor angiotensin converting enzyme 2 (ACE2) have been generated. These cells yielded high SARS-CoV-MA15 titers and also served as excellent tools for plaque assays. In addition, in these cell lines, SARS-CoV-MA15 induced the expression of proinflammatory cytokines and IFN-β, mimicking what has been observed in experimental animal models infected with SARS-CoV and SARS patients. These cell lines are valuable tools to perform in vitro studies in a mouse cell system that reflects the species used for in vivo studies of SARS-CoV-MA15 pathogenesis. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Fitting a Two-Component Scattering Model to Polarimetric SAR Data from Forests

    NASA Technical Reports Server (NTRS)

    Freeman, Anthony

    2007-01-01

    Two simple scattering mechanisms are fitted to polarimetric synthetic aperture radar (SAR) observations of forests. The mechanisms are canopy scatter from a reciprocal medium with azimuthal symmetry and a ground scatter term that can represent double-bounce scatter from a pair of orthogonal surfaces with different dielectric constants or Bragg scatter from a moderately rough surface, which is seen through a layer of vertically oriented scatterers. The model is shown to represent the behavior of polarimetric backscatter from a tropical forest and two temperate forest sites by applying it to data from the National Aeronautic and Space Agency/Jet Propulsion Laboratory's Airborne SAR (AIRSAR) system. Scattering contributions from the two basic scattering mechanisms are estimated for clusters of pixels in polarimetric SAR images. The solution involves the estimation of four parameters from four separate equations. This model fit approach is justified as a simplification of more complicated scattering models, which require many inputs to solve the forward scattering problem. The model is used to develop an understanding of the ground-trunk double-bounce scattering that is present in the data, which is seen to vary considerably as a function of incidence angle. Two parameters in the model fit appear to exhibit sensitivity to vegetation canopy structure, which is worth further exploration. Results from the model fit for the ground scattering term are compared with estimates from a forward model and shown to be in good agreement. The behavior of the scattering from the ground-trunk interaction is consistent with the presence of a pseudo-Brewster angle effect for the air-trunk scattering interface. If the Brewster angle is known, it is possible to directly estimate the real part of the dielectric constant of the trunks, a key variable in forward modeling of backscatter from forests. It is also shown how, with a priori knowledge of the forest height, an estimate for the

  10. Quick response airborne command post communications

    NASA Astrophysics Data System (ADS)

    Blaisdell, Randy L.

    1988-08-01

    National emergencies and strategic crises come in all forms and sizes ranging from natural disasters at one end of the scale up to and including global nuclear warfare at the other. Since the early 1960s the U.S. Government has spent billions of dollars fielding airborne command posts to ensure continuity of government and the command and control function during times of theater conventional, theater nuclear, and global nuclear warfare. Unfortunately, cost has prevented the extension of the airborne command post technology developed for these relatively unlikely events to the lower level, though much more likely to occur, crises such as natural disasters, terrorist acts, political insurgencies, etc. This thesis proposes the implementation of an economical airborne command post concept to address the wide variety of crises ignored by existing military airborne command posts. The system is known as the Quick Response Airborne Command Post (QRAC Post) and is based on the exclusive use of commercially owned and operated aircraft, and commercially available automated data processing and communications resources. The thesis addresses the QRAC Post concept at a systems level and is primarily intended to demonstrate how current technology can be exploited to economically achieve a national objective.

  11. The development of an airborne information management system for flight test

    NASA Technical Reports Server (NTRS)

    Bever, Glenn A.

    1992-01-01

    An airborne information management system is being developed at the NASA Dryden Flight Research Facility. This system will improve the state of the art in management data acquisition on-board research aircraft. The design centers around highly distributable, high-speed microprocessors that allow data compression, digital filtering, and real-time analysis. This paper describes the areas of applicability, approach to developing the system, potential for trouble areas, and reasons for this development activity. System architecture (including the salient points of what makes it unique), design philosophy, and tradeoff issues are also discussed.

  12. Characterizing and estimating noise in InSAR and InSAR time series with MODIS

    USGS Publications Warehouse

    Barnhart, William D.; Lohman, Rowena B.

    2013-01-01

    InSAR time series analysis is increasingly used to image subcentimeter displacement rates of the ground surface. The precision of InSAR observations is often affected by several noise sources, including spatially correlated noise from the turbulent atmosphere. Under ideal scenarios, InSAR time series techniques can substantially mitigate these effects; however, in practice the temporal distribution of InSAR acquisitions over much of the world exhibit seasonal biases, long temporal gaps, and insufficient acquisitions to confidently obtain the precisions desired for tectonic research. Here, we introduce a technique for constraining the magnitude of errors expected from atmospheric phase delays on the ground displacement rates inferred from an InSAR time series using independent observations of precipitable water vapor from MODIS. We implement a Monte Carlo error estimation technique based on multiple (100+) MODIS-based time series that sample date ranges close to the acquisitions times of the available SAR imagery. This stochastic approach allows evaluation of the significance of signals present in the final time series product, in particular their correlation with topography and seasonality. We find that topographically correlated noise in individual interferograms is not spatially stationary, even over short-spatial scales (<10 km). Overall, MODIS-inferred displacements and velocities exhibit errors of similar magnitude to the variability within an InSAR time series. We examine the MODIS-based confidence bounds in regions with a range of inferred displacement rates, and find we are capable of resolving velocities as low as 1.5 mm/yr with uncertainties increasing to ∼6 mm/yr in regions with higher topographic relief.

  13. SAR/LANDSAT image registration study

    NASA Technical Reports Server (NTRS)

    Murphrey, S. W. (Principal Investigator)

    1978-01-01

    The author has identified the following significant results. Temporal registration of synthetic aperture radar data with LANDSAT-MSS data is both feasible (from a technical standpoint) and useful (from an information-content viewpoint). The greatest difficulty in registering aircraft SAR data to corrected LANDSAT-MSS data is control-point location. The differences in SAR and MSS data impact the selection of features that will serve as a good control points. The SAR and MSS data are unsuitable for automatic computer correlation of digital control-point data. The gray-level data can not be compared by the computer because of the different response characteristics of the MSS and SAR images.

  14. Computerized ionospheric tomography based on geosynchronous SAR

    NASA Astrophysics Data System (ADS)

    Hu, Cheng; Tian, Ye; Dong, Xichao; Wang, Rui; Long, Teng

    2017-02-01

    Computerized ionospheric tomography (CIT) based on spaceborne synthetic aperture radar (SAR) is an emerging technique to construct the three-dimensional (3-D) image of ionosphere. The current studies are all based on the Low Earth Orbit synthetic aperture radar (LEO SAR) which is limited by long repeat period and small coverage. In this paper, a novel ionospheric 3-D CIT technique based on geosynchronous SAR (GEO SAR) is put forward. First, several influences of complex atmospheric environment on GEO SAR focusing are detailedly analyzed, including background ionosphere and multiple scattering effects (induced by turbulent ionosphere), tropospheric effects, and random noises. Then the corresponding GEO SAR signal model is constructed with consideration of the temporal-variant background ionosphere within the GEO SAR long integration time (typically 100 s to 1000 s level). Concurrently, an accurate total electron content (TEC) retrieval method based on GEO SAR data is put forward through subband division in range and subaperture division in azimuth, obtaining variant TEC value with respect to the azimuth time. The processing steps of GEO SAR CIT are given and discussed. Owing to the short repeat period and large coverage area, GEO SAR CIT has potentials of covering the specific space continuously and completely and resultantly has excellent real-time performance. Finally, the TEC retrieval and GEO SAR CIT construction are performed by employing a numerical study based on the meteorological data. The feasibility and correctness of the proposed methods are verified.

  15. Oil spill characterization thanks to optical airborne imagery during the NOFO campaign 2015

    NASA Astrophysics Data System (ADS)

    Viallefont-Robinet, F.; Ceamanos, X.; Angelliaume, S.; Miegebielle, V.

    2017-10-01

    One of the objectives of the NAOMI (New Advanced Observation Method Integration) research project, fruit of a partnership between Total and ONERA, is to work on the detection, the quantification and the characterization of offshore hydrocarbon at the sea surface using airborne remote sensing. In this framework, work has been done to characterize the spectral signature of hydrocarbons in lab in order to build a database of oil spectral signatures. The main objective of this database is to provide spectral libraries for data processing algorithms to be applied to airborne VNIRSWIR hyperspectral images. A campaign run by the NOFO institute (Norwegian Clean Seas Association for Operating Companies) took place in 2015 to test anti-pollution equipment. During this campaign, several hydrocarbon products, including an oil emulsion, were released into the sea, off the Norwegian coast. The NOFO team allowed the NAOMI project to acquire data over the resulting oil slicks using the SETHI system, which is an airborne remote sensing imaging system developed by ONERA. SETHI integrates a new generation of optoelectronic and radar payloads and can operate over a wide range of frequency bands. SETHI is a pod-based system operating onboard a Falcon 20 Dassault aircraft, which is owned by AvDEF. For these experiments, imaging sensors were constituted by 2 synthetic aperture radar (SAR), working at X and L bands in a full polarimetric mode (HH, HV, VH, VV) and 2 HySpex hyperspectral cameras working in the VNIR (0,4 to 1 μm) and SWIR (1 to 2,5 μm) spectral ranges. A sample of the oil emulsion that was used during the campaign was sent to our laboratory for analysis. Measurements of its transmission and of its reflectance in the VNIR and SWIR spectral domains have been performed at ONERA with a Perkin Elmer spectroradiometer and a spectrogoniometer. Several samples of the oil emulsion were prepared in order to measure spectral variations according to oil thickness, illumination angle

  16. Combined observations of Arctic sea ice with near-coincident colocated X-band, C-band, and L-band SAR satellite remote sensing and helicopter-borne measurements

    NASA Astrophysics Data System (ADS)

    Johansson, A. M.; King, J. A.; Doulgeris, A. P.; Gerland, S.; Singha, S.; Spreen, G.; Busche, T.

    2017-01-01

    In this study, we compare colocated near-coincident X-, C-, and L-band fully polarimetry SAR satellite images with helicopter-borne ice thickness measurements acquired during the Norwegian Young sea ICE 2015 (N-ICE2015) expedition in the region of the Arctic Ocean north of Svalbard in April 2015. The air-borne surveys provide near-coincident snow plus ice thickness, surface roughness data, and photographs. This unique data set allows us to investigate how the different frequencies can complement one another for sea ice studies, but also to raise awareness of limitations. X-band and L-band satellite scenes were shown to be a useful complement to the standard SAR frequency for sea ice monitoring (C-band) for lead ice and newly formed sea ice identification. This may be in part be due to the frequency but also the high spatial resolution of these sensors. We found a relatively low correlation between snow plus ice thickness and surface roughness. Therefore, in our dataset ice thickness cannot directly be observed by SAR which has important implications for operational ice charting based on automatic segmentation.

  17. Segmentation of Polarimetric SAR Images Usig Wavelet Transformation and Texture Features

    NASA Astrophysics Data System (ADS)

    Rezaeian, A.; Homayouni, S.; Safari, A.

    2015-12-01

    Polarimetric Synthetic Aperture Radar (PolSAR) sensors can collect useful observations from earth's surfaces and phenomena for various remote sensing applications, such as land cover mapping, change and target detection. These data can be acquired without the limitations of weather conditions, sun illumination and dust particles. As result, SAR images, and in particular Polarimetric SAR (PolSAR) are powerful tools for various environmental applications. Unlike the optical images, SAR images suffer from the unavoidable speckle, which causes the segmentation of this data difficult. In this paper, we use the wavelet transformation for segmentation of PolSAR images. Our proposed method is based on the multi-resolution analysis of texture features is based on wavelet transformation. Here, we use the information of gray level value and the information of texture. First, we produce coherency or covariance matrices and then generate span image from them. In the next step of proposed method is texture feature extraction from sub-bands is generated from discrete wavelet transform (DWT). Finally, PolSAR image are segmented using clustering methods as fuzzy c-means (FCM) and k-means clustering. We have applied the proposed methodology to full polarimetric SAR images acquired by the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) L-band system, during July, in 2012 over an agricultural area in Winnipeg, Canada.

  18. Satellite SAR geocoding with refined RPC model

    NASA Astrophysics Data System (ADS)

    Zhang, Lu; Balz, Timo; Liao, Mingsheng

    2012-04-01

    Recent studies have proved that the Rational Polynomial Camera (RPC) model is able to act as a reliable replacement of the rigorous Range-Doppler (RD) model for the geometric processing of satellite SAR datasets. But its capability in absolute geolocation of SAR images has not been evaluated quantitatively. Therefore, in this article the problems of error analysis and refinement of SAR RPC model are primarily investigated to improve the absolute accuracy of SAR geolocation. Range propagation delay and azimuth timing error are identified as two major error sources for SAR geolocation. An approach based on SAR image simulation and real-to-simulated image matching is developed to estimate and correct these two errors. Afterwards a refined RPC model can be built from the error-corrected RD model and then used in satellite SAR geocoding. Three experiments with different settings are designed and conducted to comprehensively evaluate the accuracies of SAR geolocation with both ordinary and refined RPC models. All the experimental results demonstrate that with RPC model refinement the absolute location accuracies of geocoded SAR images can be improved significantly, particularly in Easting direction. In another experiment the computation efficiencies of SAR geocoding with both RD and RPC models are compared quantitatively. The results show that by using the RPC model such efficiency can be remarkably improved by at least 16 times. In addition the problem of DEM data selection for SAR image simulation in RPC model refinement is studied by a comparative experiment. The results reveal that the best choice should be using the proper DEM datasets of spatial resolution comparable to that of the SAR images.

  19. Latest Advancement In Airborne Relative Gravity Instrumentation.

    NASA Astrophysics Data System (ADS)

    Brady, N.

    2011-12-01

    Airborne gravity surveying has been performed with widely varying degrees of success since early experimentation with the Lacoste and Romberg dynamic meter in the 1950s. There are a number of different survey systems currently in operation including relative gravity meters and gradiometers. Airborne gravity is ideally suited to rapid, wide coverage surveying and is not significantly more expensive in more remote and inhospitable terrain which makes airborne measurements one of the few viable options available for cost effective exploration. As improved instrumentation has become available, scientific applications have also been able to take advantage for use in determining sub surface geologic structures, for example under ice sheets in Antarctica, and more recently direct measurement of the geoid to improve the vertical datum in the United States. In 2004, Lacoste and Romberg (now Micro-g Lacoste) decided to build on their success with the newly developed AirSea II dynamic meter and use that system as the basis for a dedicated airborne gravity instrument. Advances in electronics, timing and positioning technology created the opportunity to refine both the hardware and software, and to develop a truly turnkey system that would work well for users with little or no airborne gravity experience as well as those with more extensive experience. The resulting Turnkey Airborne Gravity System (TAGS) was successfully introduced in 2007 and has since been flown in applications from oil, gas and mineral exploration surveys to regional gravity mapping and geoid mapping. The system has been mounted in a variety of airborne platforms including depending on the application of interest. The development experience with the TAGS enabled Micro-g Lacoste to embark on a new project in 2010 to completely redesign the mechanical and electronic components of the system rather than continuing incremental upgrades. Building on the capabilities of the original TAGS, the objectives for the

  20. Research on Multi-Temporal PolInSAR Modeling and Applications

    NASA Astrophysics Data System (ADS)

    Hong, Wen; Pottier, Eric; Chen, Erxue

    2014-11-01

    In the study of theory and processing methodology, we apply accurate topographic phase to the Freeman-Durden decomposition for PolInSAR data. On the other hand, we present a TomoSAR imaging method based on convex optimization regularization theory. The target decomposition and reconstruction performance will be evaluated by multi-temporal Land P-band fully polarimetric images acquired in BioSAR campaigns. In the study of hybrid Quad-Pol system performance, we analyse the expression of range ambiguity to signal ratio (RASR) in this architecture. Simulations are used to testify its advantage in the improvement of range ambiguities.

  1. Research on Multi-Temporal PolInSAR Modeling and Applications

    NASA Astrophysics Data System (ADS)

    Hong, Wen; Pottier, Eric; Chen, Erxue

    2014-11-01

    In the study of theory and processing methodology, we apply accurate topographic phase to the Freeman- Durden decomposition for PolInSAR data. On the other hand, we present a TomoSAR imaging method based on convex optimization regularization theory. The target decomposition and reconstruction performance will be evaluated by multi-temporal L- and P-band fully polarimetric images acquired in BioSAR campaigns. In the study of hybrid Quad-Pol system performance, we analyse the expression of range ambiguity to signal ratio (RASR) in this architecture. Simulations are used to testify its advantage in the improvement of range ambiguities.

  2. Monitoring of Three Case Studies of Creeping Landslides in Ecuador using L-band SAR Interferometry (InSAR)

    NASA Astrophysics Data System (ADS)

    Mayorga Torres, T. M.; Mohseni Aref, M.

    2015-12-01

    Tannia Mayorga Torres1,21 Universidad Central del Ecuador. Faculty of Geology, Mining, Oil, and Environment 2 Hubert H. Humphrey Fellowship 2015-16 IntroductionLandslides lead to human and economic losses across the country, mainly in the winter season. On the other hand, satellite radar data has cost-effective benefits due to open-source software and free availability of data. With the purpose of establishing an early warning system of landslide-related surface deformation, three case studies were designed in the Coast, Sierra (Andean), and Oriente (jungle) regions. The objective of this work was to assess the capability of L-band InSAR to get phase information. For the calculation of the interferograms in Repeat Orbit Interferometry PACkage, the displacement was detected as the error and was corrected. The coherence images (Figure 1) determined that L-band is suitable for InSAR processing. Under this frame, as a first approach, the stacking DInSAR technique [1] was applied in the case studies [2]; however, due to lush vegetation and steep topography, it is necessary to apply advanced InSAR techniques [3]. The purpose of the research is to determine a pattern of data acquisition and successful results to understand the spatial and temporal ground movements associated with landslides. The further work consists of establishing landslide inventories to combine phases of SAR images to generate maps of surface deformation in Tumba-San Francisco and Guarumales to compare the results with ground-based measurements to determine the maps' accuracy. References[1] Sandwell D., Price E. (1998). Phase gradient approach to stacking interferograms. Journal of Geophysical Research, Vol. 103, N. B12, pp. 30,183-30,204. [2] Mayorga T., Platzeck G. (2014). Using DInSAR as a tool to detect unstable terrain areas in an Andes region in Ecuador. NH3.5-Blue Poster B298, Vol. 16, EGU2014-16203. Austria. [3] Wasowski J., Bovenga F. (2014). Investigating landslides and unstable slopes with

  3. High Resolution X-Band SAR Constallation for Risk Management

    DTIC Science & Technology

    2000-10-01

    polarisation has been specified to two unique, alternative SAR-satellite designs which as no specific requirement exists for dual- polarisation combine...dispersion while Fig. 4a). beam -scanning; 5 azimuth power splitters which feed the sub- 2. An architecture borrowed from modem panels...resolution SAR constellation therefore forms an essential Polarisation HH (or VV) component of such an observation system which shall Mean/max revisit < 12/24

  4. The InSAR Scientific Computing Environment (ISCE): An Earth Science SAR Processing Framework, Toolbox, and Foundry

    NASA Astrophysics Data System (ADS)

    Agram, P. S.; Gurrola, E. M.; Lavalle, M.; Sacco, G. F.; Rosen, P. A.

    2016-12-01

    The InSAR Scientific Computing Environment (ISCE) provides both a modular, flexible, and extensible framework for building software components and applications that work together seamlessly as well as a toolbox for processing InSAR data into higher level geodetic image products from a diverse array of radar satellites and aircraft. ISCE easily scales to serve as the SAR processing engine at the core of the NASA JPL Advanced Rapid Imaging and Analysis (ARIA) Center for Natural Hazards as well as a software toolbox for individual scientists working with SAR data. ISCE is planned as the foundational element in processing NISAR data, enabling a new class of analyses that take greater advantage of the long time and large spatial scales of these data. ISCE in ARIA is also a SAR Foundry for development of new processing components and workflows to meet the needs of both large processing centers and individual users. The ISCE framework contains object-oriented Python components layered to construct Python InSAR components that manage legacy Fortran/C InSAR programs. The Python user interface enables both command-line deployment of workflows as well as an interactive "sand box" (the Python interpreter) where scientists can "play" with the data. Recent developments in ISCE include the addition of components to ingest Sentinel-1A SAR data (both stripmap and TOPS-mode) and a new workflow for processing the TOPS-mode data. New components are being developed to exploit polarimetric-SAR data to provide the ecosystem and land-cover/land-use change communities with rigorous and efficient tools to perform multi-temporal, polarimetric and tomographic analyses in order to generate calibrated, geocoded and mosaicked Level-2 and Level-3 products (e.g., maps of above-ground biomass or forest disturbance). ISCE has been downloaded by over 200 users by a license for WinSAR members through the Unavco.org website. Others may apply directly to JPL for a license at download.jpl.nasa.gov.

  5. Controlling Data Collection to Support SAR Image Rotation

    DOEpatents

    Doerry, Armin W.; Cordaro, J. Thomas; Burns, Bryan L.

    2008-10-14

    A desired rotation of a synthetic aperture radar (SAR) image can be facilitated by adjusting a SAR data collection operation based on the desired rotation. The SAR data collected by the adjusted SAR data collection operation can be efficiently exploited to form therefrom a SAR image having the desired rotational orientation.

  6. 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.

  7. Hazards of Gulf Coast Subsidence: Crustal Loading, Geodesy, InSAR and UAVSAR Observations

    NASA Astrophysics Data System (ADS)

    Blom, R. G.; Chapman, B. D.; Dokka, R. K.; Fielding, E. J.; Hensley, S.; Ivins, E. R.; Lohman, R. B.

    2009-12-01

    interferometry (InSAR) using both satellite and airborne radars. The Gulf Coast is a very challenging environment for InSAR techniques and we are developing new persistent scatterer methods to apply to available C-band satellite radar data. More recent L-Band PALSAR satellite data are suitable for conventional interferometry. We are also making new observations with NASA/JPL’s new airborne interferometer system UAVSAR (http://uavsar.jpl.nasa.gov/). The high spatial resolution UAVSAR data has the potential to monitor levees and other critical infrastructure better than satellites. We review work to date and present newly acquired UAVSAR data.

  8. Further SEASAT SAR coastal ocean wave analysis

    NASA Technical Reports Server (NTRS)

    Kasischke, E. S.; Shuchman, R. A.; Meadows, G. A.; Jackson, P. L.; Tseng, Y.

    1981-01-01

    Analysis techniques used to exploit SEASAT synthetic aperture radar (SAR) data of gravity waves are discussed and the SEASAT SAR's ability to monitor large scale variations in gravity wave fields in both deep and shallow water is evaluated. The SAR analysis techniques investigated included motion compensation adjustments and the semicausal model for spectral analysis of SAR wave data. It was determined that spectra generated from fast Fourier transform analysis (FFT) of SAR wave data were not significantly altered when either range telerotation adjustments or azimuth focus shifts were used during processing of the SAR signal histories, indicating that SEASAT imagery of gravity waves is not significantly improved or degraded by motion compensation adjustments. Evaluation of the semicausal (SC) model using SEASAT SAR data from Rev. 974 indicates that the SC spectral estimates were not significantly better than the FFT results.

  9. Global Test Range: Toward Airborne Sensor Webs

    NASA Technical Reports Server (NTRS)

    Mace, Thomas H.; Freudinger, Larry; DelFrate John H.

    2008-01-01

    This viewgraph presentation reviews the planned global sensor network that will monitor the Earth's climate, and resources using airborne sensor systems. The vision is an intelligent, affordable Earth Observation System. Global Test Range is a lab developing trustworthy services for airborne instruments - a specialized Internet Service Provider. There is discussion of several current and planned missions.

  10. SARS-related perceptions in Hong Kong.

    PubMed

    Lau, Joseph T F; Yang, Xilin; Pang, Ellie; Tsui, H Y; Wong, Eric; Wing, Yun Kwok

    2005-03-01

    To understand different aspects of community responses related to severe acute respiratory syndrome (SARS), 2 population-based, random telephone surveys were conducted in June 2003 and January 2004 in Hong Kong. More than 70% of respondents would avoid visiting hospitals or mainland China to avoid contracting SARS. Most respondents believed that SARS could be transmitted through droplets, fomites, sewage, and animals. More than 90% believed that public health measures were efficacious means of prevention; 40.4% believed that SARS would resurge in Hong Kong; and approximately equals 70% would then wear masks in public places. High percentages of respondents felt helpless, horrified, and apprehensive because of SARS. Approximately 16% showed signs of posttraumatic symptoms, and approximately equals 40% perceived increased stress in family or work settings. The general public in Hong Kong has been very vigilant about SARS but needs to be more psychologically prepared to face a resurgence of the epidemic.

  11. SARS-related Perceptions in Hong Kong

    PubMed Central

    Yang, Xilin; Pang, Ellie; Tsui, H.Y.; Wong, Eric; Wing, Yun Kwok

    2005-01-01

    To understand different aspects of community responses related to severe acute respiratory syndrome (SARS), 2 population-based, random telephone surveys were conducted in June 2003 and January 2004 in Hong Kong. More than 70% of respondents would avoid visiting hospitals or mainland China to avoid contracting SARS. Most respondents believed that SARS could be transmitted through droplets, fomites, sewage, and animals. More than 90% believed that public health measures were efficacious means of prevention; 40.4% believed that SARS would resurge in Hong Kong; and ≈70% would then wear masks in public places. High percentages of respondents felt helpless, horrified, and apprehensive because of SARS. Approximately 16% showed signs of posttraumatic symptoms, and ≈40% perceived increased stress in family or work settings. The general public in Hong Kong has been very vigilant about SARS but needs to be more psychologically prepared to face a resurgence of the epidemic. PMID:15757557

  12. Positional Accuracy of Airborne Integrated Global Positioning and Inertial Navigation Systems for Mapping in Glen Canyon, Arizona

    USGS Publications Warehouse

    Sanchez, Richard D.; Hothem, Larry D.

    2002-01-01

    High-resolution airborne and satellite image sensor systems integrated with onboard data collection based on the Global Positioning System (GPS) and inertial navigation systems (INS) may offer a quick and cost-effective way to gather accurate topographic map information without ground control or aerial triangulation. The Applanix Corporation?s Position and Orientation Solutions for Direct Georeferencing of aerial photography was used in this project to examine the positional accuracy of integrated GPS/INS for terrain mapping in Glen Canyon, Arizona. The research application in this study yielded important information on the usefulness and limits of airborne integrated GPS/INS data-capture systems for mapping.

  13. The Theoretical Problem of Partial Coherence and Partial Polarization in PolSAR and PolInSAR

    NASA Astrophysics Data System (ADS)

    Alvarez-Perez, J. L.

    2013-08-01

    Coherence is a key concept in all aspects related to SAR, and it is also an essential ingredient not only of its signal processing and image formation but also of the data postprocessing stages of SAR data. Coherence is however a non-trivial concept that has been the subject of much debate in the last sixty years, even if its definition in the context of PolInSAR has been almost univocal. Nevertheless, the mutual relationships between coherence, polarization and statistical independence in PolSAR has recently been the subject of discussion in [1]. Some of these questions affect the eigenanalysis-based approach to PolInSAR, as developed by Cloude and Papathanassiou's foundational work. Coherence involves the behaviour of electromagnetic waves in at least a pair of points and in this sense it plays an important role in interferometry that is not present in non-interferometric radar polarimetry. PolInSAR inherits some of the difficulties found in [1], which stem from the controversial confusion between coherence and polarization as present in PolSAR, as well as the ability of separating different physical contributors to the scattering phenomenon through the use of eigenvalues and eigenvectors. Although these are also issues present in eigenanalysis-based PolInSAR, it is still possible to analyze a scene in terms of coherence and this very concept of coherence is the subject of this paper. A new analysis of the concept of coherence for interferometry is proposed, including multiple observation point configurations that bring about statistical moments whose order is higher than two.

  14. The SARVIEWS Project: Automated SAR Processing in Support of Operational Near Real-time Volcano Monitoring

    NASA Astrophysics Data System (ADS)

    Meyer, F. J.; Webley, P. W.; Dehn, J.; Arko, S. A.; McAlpin, D. B.; Gong, W.

    2016-12-01

    Volcanic eruptions are among the most significant hazards to human society, capable of triggering natural disasters on regional to global scales. In the last decade, remote sensing has become established in operational volcano monitoring. Centers like the Alaska Volcano Observatory rely heavily on remote sensing data from optical and thermal sensors to provide time-critical hazard information. Despite this high use of remote sensing data, the presence of clouds and a dependence on solar illumination often limit their impact on decision making. Synthetic Aperture Radar (SAR) systems are widely considered superior to optical sensors in operational monitoring situations, due to their weather and illumination independence. Still, the contribution of SAR to operational volcano monitoring has been limited in the past due to high data costs, long processing times, and low temporal sampling rates of most SAR systems. In this study, we introduce the automatic SAR processing system SARVIEWS, whose advanced data analysis and data integration techniques allow, for the first time, a meaningful integration of SAR into operational monitoring systems. We will introduce the SARVIEWS database interface that allows for automatic, rapid, and seamless access to the data holdings of the Alaska Satellite Facility. We will also present a set of processing techniques designed to automatically generate a set of SAR-based hazard products (e.g. change detection maps, interferograms, geocoded images). The techniques take advantage of modern signal processing and radiometric normalization schemes, enabling the combination of data from different geometries. Finally, we will show how SAR-based hazard information is integrated in existing multi-sensor decision support tools to enable joint hazard analysis with data from optical and thermal sensors. We will showcase the SAR processing system using a set of recent natural disasters (both earthquakes and volcanic eruptions) to demonstrate its

  15. Severe acute respiratory syndrome (SARS): knowledge, attitudes, practices and sources of information among physicians answering a SARS fever hotline service.

    PubMed

    Deng, J-F; Olowokure, B; Kaydos-Daniels, S C; Chang, H-J; Barwick, R S; Lee, M-L; Deng, C-Y; Factor, S H; Chiang, C-E; Maloney, S A

    2006-01-01

    In June 2003, Taiwan introduced a severe acute respiratory syndrome (SARS) telephone hotline service to provide concerned callers with rapid access to information, advice and appropriate referral where necessary. This paper reports an evaluation of the knowledge, attitude, practices and sources of information relating to SARS among physicians who staffed the SARS fever hotline service. A retrospective survey was conducted using a self-administered postal questionnaire. Participants were physicians who staffed a SARS hotline during the SARS epidemic in Taipei, Taiwan from June 1 to 10, 2003. A response rate of 83% was obtained. All respondents knew the causative agent of SARS, and knowledge regarding SARS features and preventive practices was good. However, only 54% of respondents knew the incubation period of SARS. Hospital guidelines and news media were the major information sources. In responding to two case scenarios most physicians were likely to triage callers at high risk of SARS appropriately, but not callers at low risk. Less than half of all respondents answered both scenarios correctly. The results obtained suggest that knowledge of SARS was generally good although obtained from both medical and non-medical sources. Specific knowledge was however lacking in certain areas and this affected the ability to appropriately triage callers. Standardized education and assessment of prior knowledge of SARS could improve the ability of physicians to triage callers in future outbreaks.

  16. Infrared airborne spectroradiometer survey results in the western Nevada area

    NASA Technical Reports Server (NTRS)

    Collins, W.; Chang, S. H.; Kuo, J. T.

    1982-01-01

    The Mark II airborne spectroradiometer system was flown over several geologic test sites in western Nevada. The infrared mineral absorption bands were observed and recorded for the first time using an airborne system with high spectral resolution in the 2.0 to 2.5 micron region. The data show that the hydrothermal alteration zone minerals, carbonates, and other minerals are clearly visible in the airborne survey mode. The finer spectral features that distinguish the various minerals with infrared bands are also clearly visible in the airborne survey data. Using specialized computer pattern recognition methods, it is possible to identify mineralogy and map alteration zones and lithologies by airborne spectroradiometer survey techniques.

  17. How change of public transportation usage reveals fear of the SARS virus in a city.

    PubMed

    Wang, Kuo-Ying

    2014-01-01

    The outbreaks of the severe acute respiratory syndrome (SARS) epidemic in 2003 resulted in unprecedented impacts on people's daily life. One of the most significant impacts to people is the fear of contacting the SARS virus while engaging daily routine activity. Here we use data from daily underground ridership in Taipei City and daily reported new SARS cases in Taiwan to model the dynamics of the public fear of the SARS virus during the wax and wane of the SARS period. We found that for each reported new SARS case there is an immediate loss of about 1200 underground ridership (the fresh fear). These daily loss rates dissipate to the following days with an e-folding time of about 28 days, reflecting the public perception on the risk of contacting SARS virus when traveling with the underground system (the residual fear). About 50% of daily ridership was lost during the peak of the 2003 SARS period, compared with the loss of 80% daily ridership during the closure of the underground system after Typhoon Nari, the loss of 50-70% ridership due to the closure of the governmental offices and schools during typhoon periods, and the loss of 60% daily ridership during Chinese New Year holidays.

  18. How Change of Public Transportation Usage Reveals Fear of the SARS Virus in a City

    PubMed Central

    Wang, Kuo-Ying

    2014-01-01

    The outbreaks of the severe acute respiratory syndrome (SARS) epidemic in 2003 resulted in unprecedented impacts on people's daily life. One of the most significant impacts to people is the fear of contacting the SARS virus while engaging daily routine activity. Here we use data from daily underground ridership in Taipei City and daily reported new SARS cases in Taiwan to model the dynamics of the public fear of the SARS virus during the wax and wane of the SARS period. We found that for each reported new SARS case there is an immediate loss of about 1200 underground ridership (the fresh fear). These daily loss rates dissipate to the following days with an e-folding time of about 28 days, reflecting the public perception on the risk of contacting SARS virus when traveling with the underground system (the residual fear). About 50% of daily ridership was lost during the peak of the 2003 SARS period, compared with the loss of 80% daily ridership during the closure of the underground system after Typhoon Nari, the loss of 50–70% ridership due to the closure of the governmental offices and schools during typhoon periods, and the loss of 60% daily ridership during Chinese New Year holidays. PMID:24647278

  19. Status of the Signals of Opportunity Airborne Demonstrator (SoOp-AD)

    NASA Technical Reports Server (NTRS)

    Garrison, Jim; Lin, Yao-Cheng; Piepmeier, Jeff; Knuble, Joe; Hersey, Ken; Du Toit, Cornelus; Joseph, Alicia; Deshpande, Manohar; Alikakos, George; O'Brien, Steve; hide

    2016-01-01

    Root zone soil moisture (RZSM) is not directly measured by any current satellite instrument, despite its importance as a key link between surface hydrology and deeper processes. Presently, model assimilation of surface measurements or indirect estimates using other methods must be used to estimate this value. Signals of Opportunity (SoOp) methods, exploiting reflected P- and S-band communication satellite signals, have many of the benefits of both active and passive microwave remote sensing. Reutilization of active transmitters, with forward-scattering geometry, presents a strong reflected signal even at orbital altitudes. Microwave radiometry is advantageous as it measures emissivity, which is directly related to dielectric constant and sensitive to water content of soil. Synthetic aperture radar (SAR) is used in P-band (400 MHz) for soil moisture and biomass, but faces issues in obtaining permission to transmit due to spectrum regulations, particularly over North America and Europe. A primary advantage of SAR is excellent spatial resolution. Signals-of-opportunity (SoOp) reflectometry provides a good compromise between radiometry and SAR by providing decent sensitivity and special resolution for RZSM measurements without issues of spectrum access. Further, a SoOp instrument would not be limited to operating in only a few protected frequencies and is also expected to have less susceptibility to radio-frequency interference (RFI). Although advantageous if available, SoOp techniques do not require the ability to demodulate or decode the communication signals. The SoOp instrument is receive only and therefore requires much less electrical power than a SAR and is more similar to a radiometer in receiver architecture. These unique features of SoOp circumvent past obstacles to a spaceborne P-band remote sensing mission and have the potential to enable new RZSM measurements that are not possible with present technology. We will present the latest development status of a

  20. 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.

  1. New Atmospheric Observations from the Airborne GNSS Instrument System for Multistatic and Occultation Sensing (GISMOS)

    NASA Astrophysics Data System (ADS)

    Haase, J. S.; Xie, F.; Muradyan, P.; Garrison, J. L.; Lulich, T.; Voo, J.; Larson, K. M.

    2008-12-01

    The Airborne GNSS Instrument System for Multistatic and Occultation Sensing (GISMOS) was deployed on the NCAR HIAPER (High-performance Instrumented Airborne Platform for Environmental Research) aircraft to make atmospheric observations over the Gulf of Mexico coastal region in February 2008. The objective of the measurements was to test the performance of the system in comparisons with radiosonde profiles and dropsonde profiles that were also collected during the field campaign. The airborne GNSS radio occultation measures of GNSS signals from satellites that are setting or rising behind the Earth's limb relative to the receiver on board an aircraft. High-gain side-looking antennas and a 10MHz GPS Recording System that records the raw RF signal make this set of instrumentation unique, and especially adapted for open-loop tracking observations in the lower atmosphere. Measurements of the amount of refraction in the signal ray paths are inverted using an Abel transform procedure to retrieve a profile of refractivity, which depends on atmospheric pressure, temperature and relative humidity. The airborne geometry, in contrast to the space- borne satellite occultation geometry, is affected by a large drift in the tangent point location, that is the location of the closest point to the Earth surface, as the ray path descends in the atmosphere. Therefore plans for the validation campaign included releasing dropsondes in the plane of the line of sight of the satellite-receiver occultation geometry in order to study this effect. Careful timing and location of the flight path was used to coordinate occultation times with operational and supplementary radiosonde launches. A total of 6 days of balloon sounding data were collected with 20 dropsondes and 28 supplementary radiosonde profiles. A discussion of the technical performance of the system will be presented, which describes the signal characteristics and antenna performance. Preliminary results on the quality of retrieved

  2. Online Health Education on SARS to University Students during the SARS Outbreak

    ERIC Educational Resources Information Center

    Wong, Mee Lian; Koh, David; Iyer, Prasad; Seow, Adeline; Goh, Lee Gan; Chia, Sin Eng; Lim, Meng Kin; Ng, Daniel; Ong, Choon Nam; Phua, Kai Hong; Tambyah, Paul; Chow, Vincent T K; Chew, Suok Kai; Chandran, Ravi; Lee, Hin Peng

    2005-01-01

    Little is known about how online learning may be used to disseminate health information rapidly and widely to large university populations if there is an infectious disease outbreak. During the SARS outbreak in Singapore in 2003, a six-lesson elearning module on SARS was developed for a large university population of 32,000 students. The module…

  3. Airborne Windshear Detection and Warning Systems. Fifth and Final Combined Manufacturers' and Technologists' Conference, part 1

    NASA Technical Reports Server (NTRS)

    Delnore, Victor E. (Compiler)

    1994-01-01

    The Fifth (and Final) Combined Manufacturers' and Technologists' Airborne Windshear Review Meeting was hosted jointly by the NASA Langley Research Center (LaRC) and the Federal Aviation Administration (FAA) in Hampton, Virginia, on September 28-30, 1993. The purpose of the meeting was to report on the highly successful windshear experiments conducted by government, academic institutions, and industry; to transfer the results to regulators, manufacturers, and users; and to set initiatives for future aeronautics technology research. The formal sessions covered recent developments in windshear flight testing; windshear modeling, flight management, and ground-based systems; airborne windshear detection systems; certification and regulatory issues; development and applications of sensors for wake vortex detection; and synthetic and enhanced vision systems.

  4. The Alaska SAR processor - Operations and control

    NASA Technical Reports Server (NTRS)

    Carande, Richard E.

    1989-01-01

    The Alaska SAR (synthetic-aperture radar) Facility (ASF) will be capable of receiving, processing, archiving, and producing a variety of SAR image products from three satellite-borne SARs: E-ERS-1 (ESA), J-ERS-1 (NASDA) and Radarsat (Canada). Crucial to the success of the ASF is the Alaska SAR processor (ASP), which will be capable of processing over 200 100-km x 100-km (Seasat-like) frames per day from the raw SAR data, at a ground resolution of about 30 m x 30 m. The processed imagery is of high geometric and radiometric accuracy, and is geolocated to within 500 m. Special-purpose hardware has been designed to execute a SAR processing algorithm to achieve this performance. This hardware is currently undergoing acceptance testing for delivery to the University of Alaska. Particular attention has been devoted to making the operations semi-automated and to providing a friendly operator interface via a computer workstation. The operations and control of the Alaska SAR processor are described.

  5. 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.

  6. Automated Mounting Bias Calibration for Airborne LIDAR System

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

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

  7. Segmentation Of Polarimetric SAR Data

    NASA Technical Reports Server (NTRS)

    Rignot, Eric J. M.; Chellappa, Rama

    1994-01-01

    Report presents one in continuing series of studies of segmentation of polarimetric synthetic-aperture-radar, SAR, image data into regions. Studies directed toward refinement of method of automated analysis of SAR data.

  8. CLASS: Coherent Lidar Airborne Shear Sensor. Windshear avoidance

    NASA Technical Reports Server (NTRS)

    Targ, Russell

    1991-01-01

    The coherent lidar airborne shear sensor (CLASS) is an airborne CO2 lidar system being designed and developed by Lockheed Missiles and Space Company, Inc. (LMSC) under contract to NASA Langley Research Center. The goal of this program is to develop a system with a 2- to 4-kilometer range that will provide a warning time of 20 to 40 seconds, so that the pilot can avoid the hazards of low-altitude wind shear under all weather conditions. It is a predictive system which will warn the pilot about a hazard that the aircraft will experience at some later time. The ability of the system to provide predictive warnings of clear air turbulence will also be evaluated. A one-year flight evaluation program will measure the line-of-sight wind velocity from a wide variety of wind fields obtained by an airborne radar, an accelerometer-based reactive wind-sensing system, and a ground-based Doppler radar. The success of the airborne lidar system will be determined by its correlation with the windfield as indicated by the onboard reactive system, which indicates the winds actually experienced by the NASA Boeing 737 aircraft.

  9. Method for removing RFI from SAR images

    DOEpatents

    Doerry, Armin W.

    2003-08-19

    A method of removing RFI from a SAR by comparing two SAR images on a pixel by pixel basis and selecting the pixel with the lower magnitude to form a composite image. One SAR image is the conventional image produced by the SAR. The other image is created from phase-history data which has been filtered to have the frequency bands containing the RFI removed.

  10. SARS: Key factors in crisis management.

    PubMed

    Tseng, Hsin-Chao; Chen, Thai-Form; Chou, Shieu-Ming

    2005-03-01

    This study was conducted at a single hospital selected in Taipei during the SARS (Severe Acute Respiratory Syndrome) outbreak from March to July, 2003 in Taiwan. During this period of time, 104 SARS patients were admitted to the hospital. There were no negative reports related to the selected hospital despite its being located right in the center of an area struck by the epidemic. The purpose of this study was to identify the key factors enabling the hospital to survive SARS unscathed. Data were collected from in-depth interviews with the nursing directors and nursing managers of the SARS units, along with a review of relevant hospital documents. The five key elements identified as survival factors during this SARS crisis are as follows: 1. good control of timing for crisis management, 2. careful decision-making, 3. thorough implementation, 4. effective communication, and 5. trust between management and employees. The results of this study reconfirmed the selected hospital as a model for good crisis management during the SARS epidemic.

  11. 2. INTAKES, S.A.R. 2 AND KELLER CREEK, EXHIBIT L, SANTA ...

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

    2. INTAKES, S.A.R. 2 AND KELLER CREEK, EXHIBIT L, SANTA ANA RIVER NO. 2 PROJECT, APR. 30, 1945. SCE drawing no. 523639 (sheet no. 10, for filing with Federal Power Commission). - Santa Ana River Hydroelectric System, SAR-2 Intake, Redlands, San Bernardino County, CA

  12. SGA-WZ: A New Strapdown Airborne Gravimeter

    PubMed Central

    Huang, Yangming; Olesen, Arne Vestergaard; Wu, Meiping; Zhang, Kaidong

    2012-01-01

    Inertial navigation systems and gravimeters are now routinely used to map the regional gravitational quantities from an aircraft with mGal accuracy and a spatial resolution of a few kilometers. However, airborne gravimeter of this kind is limited by the inaccuracy of the inertial sensor performance, the integrated navigation technique and the kinematic acceleration determination. As the GPS technique developed, the vehicle acceleration determination is no longer the limiting factor in airborne gravity due to the cancellation of the common mode acceleration in differential mode. A new airborne gravimeter taking full advantage of the inertial navigation system is described with improved mechanical design, high precision time synchronization, better thermal control and optimized sensor modeling. Apart from the general usage, the Global Positioning System (GPS) after differentiation is integrated to the inertial navigation system which provides not only more precise altitude information along with the navigation aiding, but also an effective way to calculate the vehicle acceleration. Design description and test results on the performance of the gyroscopes and accelerations will be emphasized. Analysis and discussion of the airborne field test results are also given. PMID:23012545

  13. Helicopter Airborne Laser Positioning System (HALPS)

    NASA Technical Reports Server (NTRS)

    Eppel, Joseph C.; Christiansen, Howard; Cross, Jeffrey; Totah, Joseph

    1990-01-01

    The theory of operation, configuration, laboratory, and ground test results obtained with a helicopter airborne laser positioning system developed by Princeton University is presented. Unfortunately, due to time constraints, flight data could not be completed for presentation at this time. The system measures the relative position between two aircraft in three dimensions using two orthogonal fan-shaped laser beams sweeping across an array of four detectors. Specifically, the system calculates the relative range, elevation, and azimuth between an observation aircraft and a test helicopter with a high degree of accuracy. The detector array provides a wide field of view in the presence of solar interference due to compound parabolic concentrators and spectral filtering of the detector pulses. The detected pulses and their associated time delays are processed by the electronics and are sent as position errors to the helicopter pilot who repositions the aircraft as part of the closed loop system. Accuracies obtained in the laboratory at a range of 80 ft in the absence of sunlight were + or - 1 deg in elevation; +0.5 to -1.5 deg in azimuth; +0.5 to -1.0 ft in range; while elevation varied from 0 to +28 deg and the azimuth varied from 0 to + or - 45 deg. Accuracies in sunlight were approximately 40 deg (+ or - 20 deg) in direct sunlight.

  14. 76 FR 50808 - Airborne Supplemental Navigation Equipment Using the Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-16

    ... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Airborne Supplemental Navigation.... ACTION: Notice of intent to cancel Technical Standard Order (TSO)- C129a, Airborne Supplemental... notice announces the FAA's intent to cancel TSO-C129a, Airborne Supplemental Navigation Equipment Using...

  15. InSAR Deformation Time Series Processed On-Demand in the Cloud

    NASA Astrophysics Data System (ADS)

    Horn, W. B.; Weeden, R.; Dimarchi, H.; Arko, S. A.; Hogenson, K.

    2017-12-01

    During this past year, ASF has developed a cloud-based on-demand processing system known as HyP3 (http://hyp3.asf.alaska.edu/), the Hybrid Pluggable Processing Pipeline, for Synthetic Aperture Radar (SAR) data. The system makes it easy for a user who doesn't have the time or inclination to install and use complex SAR processing software to leverage SAR data in their research or operations. One such processing algorithm is generation of a deformation time series product, which is a series of images representing ground displacements over time, which can be computed using a time series of interferometric SAR (InSAR) products. The set of software tools necessary to generate this useful product are difficult to install, configure, and use. Moreover, for a long time series with many images, the processing of just the interferograms can take days. Principally built by three undergraduate students at the ASF DAAC, the deformation time series processing relies the new Amazon Batch service, which enables processing of jobs with complex interconnected dependencies in a straightforward and efficient manner. In the case of generating a deformation time series product from a stack of single-look complex SAR images, the system uses Batch to serialize the up-front processing, interferogram generation, optional tropospheric correction, and deformation time series generation. The most time consuming portion is the interferogram generation, because even for a fairly small stack of images many interferograms need to be processed. By using AWS Batch, the interferograms are all generated in parallel; the entire process completes in hours rather than days. Additionally, the individual interferograms are saved in Amazon's cloud storage, so that when new data is acquired in the stack, an updated time series product can be generated with minimal addiitonal processing. This presentation will focus on the development techniques and enabling technologies that were used in developing the time

  16. Multimission airborne radar for the 1990s

    NASA Astrophysics Data System (ADS)

    Robinson, Thomas H.

    1986-07-01

    The continuing trend towards the development and production of aircraft capable of multiple missions indicates that future airborne radars must provide a broad spectrum of air-to-air and air-to-ground modes. This paper investigates the modal and functional requirements of a multimode radar projected for the mid-1990s period. The paper is divided into two sections. In the first, the multimission capabilities of current radars are presented to establish trends and capabilities. In the second, the requirements of the next generation system are established. Current multimode radars lay the basis for future systems. The experience gained on the APG-65 and APG-63/70 radars is presented and conclusions are drawn regarding their impact on future system requirements. Not only are modes and performance reviewed for these radars but also their system architecture. The discussion starts with the APG-65 radar which is the first true multimission radar with programmable signal and data processing. Following this, the evolution of the APG-63 radar, culminating with the most recent upgrading resulting in redesignation of APG-70, is presented. The incorporation of air-to-ground capabilities in the APG-70, resulting from the Dual Role Fighter program, is reviewed. Results from the Advanced Fighter Capabilities Demonstration program are presented showing how high resolution SAR was incorporated into a full weapon delivery solution. The specific radar requirements for the next decade radar system are developed. This development is done in two parts. First, mode requirements are synthesized for air superiority, navigation and strike/interdiction operation. This includes low altitude penetration requirements and a review of radar timeline constraints which arise. Second, the fundamental functional requirements needed to implement the mode requirements are explored. Architectural issues and their impact on reliability and sustainability are also considered.

  17. Airborne system for detection and location of radio interference sources

    NASA Astrophysics Data System (ADS)

    Audone, Bruno; Pastore, Alberto

    1992-11-01

    The rapid expansion of telecommunication has practically saturated every band of Radio Frequency Spectrum; a similar expansion of electrical and electronic devices has affected all radio communications which are, in some way, influenced by a large amount of interferences, either intentionally or unintentionally produced. Operational consequences of these interferences, particularly in the frequency channels used for aeronautical services, can be extremely dangerous, making mandatory a tight control of Electromagnetic Spectrum. The present paper analyzes the requirements and the problems related to the surveillance, for civil application, of the Electromagnetic Spectrum between 20 and 1000 MHz, with particular attention to the detection and location of radio interference sources; after a brief introduction and the indication of the advantages of an airborne versus ground installation, the airborne system designed by Alenia in cooperation with Italian Ministry of Post and Telecommunication, its practical implementation and the prototype installation on board of a small twin turboprop aircraft for experimentation purposes is presented. The results of the flight tests are also analyzed and discussed.

  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. SAR imaging - Seeing the unseen

    NASA Technical Reports Server (NTRS)

    Kobrick, M.

    1982-01-01

    The functional abilities and operations of synthetic aperture radar (SAR) are described. SAR employs long wavelength radio waves in bursts, imaging a target by 'listening' to the small frequency changes that result from the Doppler shift due to the relative motion of the imaging craft and the motions of the target. The time delay of the signal return allows a determination of the location of the target, leading to the build up of a two-dimensional image. The uses of both Doppler shifts and time delay enable detailed imagery which is independent of distance. The synthetic aperture part of the name of SAR derives from the beaming of multiple pulses, which result in a picture that is effectively the same as using a large antenna. Mechanisms contributing to the fineness of SAR images are outlined.

  20. Risk assessment of airborne infectious diseases in aircraft cabins.

    PubMed

    Gupta, Jitendra K; Lin, Chao-Hsin; Chen, Qingyan

    2012-10-01

    Passengers in an aircraft cabin can have different risks of infection from airborne infectious diseases such as influenza, severe acute respiratory syndrome (SARS), and tuberculosis (TB) because of the non-uniform airflow in an aircraft cabin. The current investigation presents a comprehensive approach to assessing the spatial and temporal distributions of airborne infection risk in an aircraft cabin. A case of influenza outbreak was evaluated in a 4-h flight in a twin-aisle, fully occupied aircraft cabin with the index passenger seated at the center of the cabin. The approach considered the characteristics of the exhalation of the droplets carrying infectious agents from the index passenger, the dispersion of these droplets, and the inhalation of the droplets by susceptible passengers. Deterministic and probabilistic approaches were used to quantify the risks based on the amount of inhaled influenza virus RNA particles and quanta, respectively. The probabilistic approach indicated that the number of secondary infection cases can be reduced from 3 to 0 and 20 to 11, for influenza cases if N95 respirator masks are used by the passengers. The approach and methods developed can easily be implemented in other enclosed spaces such as buildings, trains, and buses to assess the infection risk. Airborne infectious disease transmission could take place in enclosed environments such as buildings and transport vehicles. The infection risk is difficult to estimate, and very few mitigation methods are available. This study used a 4-h flight as an example in analyzing the infection risk from influenza and in mitigating the risk with an N95 mask. The results will be useful to the airline industry in providing necessary protection to passengers and crew, and the results can also be used for other enclosed spaces. © 2012 John Wiley & Sons A/S.

  1. An archival analysis of stall warning system effectiveness during airborne icing encounters

    NASA Astrophysics Data System (ADS)

    Maris, John Michael

    An archival study was conducted to determine the influence of stall warning system performance on aircrew decision-making outcomes during airborne icing encounters. A Conservative Icing Response Bias (CIRB) model was developed to explain the historical variability in aircrew performance in the face of airframe icing. The model combined Bayes' Theorem with Signal Detection Theory (SDT) concepts to yield testable predictions that were evaluated using a Binary Logistic Regression (BLR) multivariate technique applied to two archives: the NASA Aviation Safety Reporting System (ASRS) incident database, and the National Transportation Safety Board (NTSB) accident databases, both covering the period January 1, 1988 to October 2, 2015. The CIRB model predicted that aircrew would experience more incorrect response outcomes in the face of missed stall warnings than with stall warning False Alarms. These predicted outcomes were observed at high significance levels in the final sample of 132 NASA/NTSB cases. The CIRB model had high sensitivity and specificity, and explained 71.5% (Nagelkerke R2) of the variance of aircrew decision-making outcomes during the icing encounters. The reliability and validity metrics derived from this study suggest indicate that the findings are generalizable to the population of U.S. registered turbine-powered aircraft. These findings suggest that icing-related stall events could be reduced if the incidence of stall warning Misses could be minimized. Observed stall warning Misses stemmed from three principal causes: aerodynamic icing effects, which reduced the stall angle-of-attack (AoA) to below the stall warning calibration threshold; tail stalls, which are not monitored by contemporary protection systems; and icing-induced system issues (such as frozen pitot tubes), which compromised stall warning system effectiveness and airframe envelope protections. Each of these sources of missed stall warnings could be addressed by Aerodynamic Performance

  2. Ground deformation monitoring using RADARSAT-2 DInSAR-MSBAS at the Aquistore CO2 storage site in Saskatchewan (Canada)

    NASA Astrophysics Data System (ADS)

    Czarnogorska, M.; Samsonov, S.; White, D.

    2014-11-01

    The research objectives of the Aquistore CO2 storage project are to design, adapt, and test non-seismic monitoring methods for measurement, and verification of CO2 storage, and to integrate data to determine subsurface fluid distributions, pressure changes and associated surface deformation. Aquistore site is located near Estevan in Southern Saskatchewan on the South flank of the Souris River and west of the Boundary Dam Power Station and the historical part of Estevan coal mine in southeastern Saskatchewan, Canada. Several monitoring techniques were employed in the study area including advanced satellite Differential Interferometric Synthetic Aperture Radar (DInSAR) technique, GPS, tiltmeters and piezometers. The targeted CO2 injection zones are within the Winnipeg and Deadwood formations located at > 3000 m depth. An array of monitoring techniques was employed in the study area including advanced satellite Differential Interferometric Synthetic Aperture Radar (DInSAR) with established corner reflectors, GPS, tiltmeters and piezometers stations. We used airborne LIDAR data for topographic phase estimation, and DInSAR product geocoding. Ground deformation maps have been calculated using Multidimensional Small Baseline Subset (MSBAS) methodology from 134 RADARSAT-2 images, from five different beams, acquired during 20120612-20140706. We computed and interpreted nine time series for selected places. MSBAS results indicate slow ground deformation up to 1 cm/year not related to CO2 injection but caused by various natural and anthropogenic causes.

  3. A double epidemic model for the SARS propagation

    PubMed Central

    Ng, Tuen Wai; Turinici, Gabriel; Danchin, Antoine

    2003-01-01

    Background An epidemic of a Severe Acute Respiratory Syndrome (SARS) caused by a new coronavirus has spread from the Guangdong province to the rest of China and to the world, with a puzzling contagion behavior. It is important both for predicting the future of the present outbreak and for implementing effective prophylactic measures, to identify the causes of this behavior. Results In this report, we show first that the standard Susceptible-Infected-Removed (SIR) model cannot account for the patterns observed in various regions where the disease spread. We develop a model involving two superimposed epidemics to study the recent spread of the SARS in Hong Kong and in the region. We explore the situation where these epidemics may be caused either by a virus and one or several mutants that changed its tropism, or by two unrelated viruses. This has important consequences for the future: the innocuous epidemic might still be there and generate, from time to time, variants that would have properties similar to those of SARS. Conclusion We find that, in order to reconcile the existing data and the spread of the disease, it is convenient to suggest that a first milder outbreak protected against the SARS. Regions that had not seen the first epidemic, or that were affected simultaneously with the SARS suffered much more, with a very high percentage of persons affected. We also find regions where the data appear to be inconsistent, suggesting that they are incomplete or do not reflect an appropriate identification of SARS patients. Finally, we could, within the framework of the model, fix limits to the future development of the epidemic, allowing us to identify landmarks that may be useful to set up a monitoring system to follow the evolution of the epidemic. The model also suggests that there might exist a SARS precursor in a large reservoir, prompting for implementation of precautionary measures when the weather cools down. PMID:12964944

  4. Navigation and Remote Sensing Payloads and Methods of the Sarvant Unmanned Aerial System

    NASA Astrophysics Data System (ADS)

    Molina, P.; Fortuny, P.; Colomina, I.; Remy, M.; Macedo, K. A. C.; Zúnigo, Y. R. C.; Vaz, E.; Luebeck, D.; Moreira, J.; Blázquez, M.

    2013-08-01

    In a large number of scenarios and missions, the technical, operational and economical advantages of UAS-based photogrammetry and remote sensing over traditional airborne and satellite platforms are apparent. Airborne Synthetic Aperture Radar (SAR) or combined optical/SAR operation in remote areas might be a case of a typical "dull, dirty, dangerous" mission suitable for unmanned operation - in harsh environments such as for example rain forest areas in Brazil, topographic mapping of small to medium sparsely inhabited remote areas with UAS-based photogrammetry and remote sensing seems to be a reasonable paradigm. An example of such a system is the SARVANT platform, a fixed-wing aerial vehicle with a six-meter wingspan and a maximumtake- of-weight of 140 kilograms, able to carry a fifty-kilogram payload. SARVANT includes a multi-band (X and P) interferometric SAR payload, as the P-band enables the topographic mapping of densely tree-covered areas, providing terrain profile information. Moreover, the combination of X- and P-band measurements can be used to extract biomass estimations. Finally, long-term plan entails to incorporate surveying capabilities also at optical bands and deliver real-time imagery to a control station. This paper focuses on the remote-sensing concept in SARVANT, composed by the aforementioned SAR sensor and envisioning a double optical camera configuration to cover the visible and the near-infrared spectrum. The flexibility on the optical payload election, ranging from professional, medium-format cameras to mass-market, small-format cameras, is discussed as a driver in the SARVANT development. The paper also focuses on the navigation and orientation payloads, including the sensors (IMU and GNSS), the measurement acquisition system and the proposed navigation and orientation methods. The latter includes the Fast AT procedure, which performs close to traditional Integrated Sensor Orientation (ISO) and better than Direct Sensor Orientation (Di

  5. SAR compliance assessment of PMR 446 and FRS walkie-talkies.

    PubMed

    Vermeeren, Günter; Joseph, Wout; Martens, Luc

    2015-10-01

    The vast amount of studies on radiofrequency dosimetry deal with exposure due to mobile devices and base station antennas for cellular communication systems. This study investigates compliance of walkie-talkies to exposure guidelines established by the International Commission on Non-Ionizing Radiation Protection and the Federal Communications Committee. The generic walkie-talkie consisted of a helical antenna and a ground plane and was derived by reverse engineering of a commercial walkie-talkie. Measured and simulated values of antenna characteristics and electromagnetic near fields of the generic walkie-talkie were within 2% and 8%, respectively. We also validated normalized electromagnetic near fields of the generic walkie-talkie against a commercial device and observed a very good agreement (deviation <6%). We showed that peak localized specific absorption rate (SAR) induced in the oval flat phantom by the generic walkie-talkie is in agreement with four commercial devices if input power of the generic walkie-talkie is rescaled based on magnetic near field. Finally, we found that SAR of commercial devices is within current SAR limits for general public exposure for a worst-case duty cycle of 100%, that is, about 3 times and 6 times lower than the limit on the 1 g SAR (1.6 W/kg) and 10 g SAR (2 W/kg), respectively. But, an effective radiated power as specified by the Private Mobile Radio at 446 MHz (PMR 446) radio standard can cause localized SAR exceeding SAR limits for 1 g of tissue. © 2015 Wiley Periodicals, Inc.

  6. Phase correction and error estimation in InSAR time series analysis

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Fattahi, H.; Amelung, F.

    2017-12-01

    During the last decade several InSAR time series approaches have been developed in response to the non-idea acquisition strategy of SAR satellites, such as large spatial and temporal baseline with non-regular acquisitions. The small baseline tubes and regular acquisitions of new SAR satellites such as Sentinel-1 allows us to form fully connected networks of interferograms and simplifies the time series analysis into a weighted least square inversion of an over-determined system. Such robust inversion allows us to focus more on the understanding of different components in InSAR time-series and its uncertainties. We present an open-source python-based package for InSAR time series analysis, called PySAR (https://yunjunz.github.io/PySAR/), with unique functionalities for obtaining unbiased ground displacement time-series, geometrical and atmospheric correction of InSAR data and quantifying the InSAR uncertainty. Our implemented strategy contains several features including: 1) improved spatial coverage using coherence-based network of interferograms, 2) unwrapping error correction using phase closure or bridging, 3) tropospheric delay correction using weather models and empirical approaches, 4) DEM error correction, 5) optimal selection of reference date and automatic outlier detection, 6) InSAR uncertainty due to the residual tropospheric delay, decorrelation and residual DEM error, and 7) variance-covariance matrix of final products for geodetic inversion. We demonstrate the performance using SAR datasets acquired by Cosmo-Skymed and TerraSAR-X, Sentinel-1 and ALOS/ALOS-2, with application on the highly non-linear volcanic deformation in Japan and Ecuador (figure 1). Our result shows precursory deformation before the 2015 eruptions of Cotopaxi volcano, with a maximum uplift of 3.4 cm on the western flank (fig. 1b), with a standard deviation of 0.9 cm (fig. 1a), supporting the finding by Morales-Rivera et al. (2017, GRL); and a post-eruptive subsidence on the same

  7. Making SAR Data Accessible - ASF's ALOS PALSAR Radiometric Terrain Correction Project

    NASA Astrophysics Data System (ADS)

    Meyer, F. J.; Arko, S. A.; Gens, R.

    2015-12-01

    While SAR data have proven valuable for a wide range of geophysical research questions, so far, largely only the SAR-educated science communities have been able to fully exploit the information content of internationally available SAR archives. The main issues that have been preventing a more widespread utilization of SAR are related to (1) the diversity and complexity of SAR data formats, (2) the complexity of the processing flows needed to extract geophysical information from SAR, (3) the lack of standardization and automation of these processing flows, and (4) the often ignored geocoding procedures, leaving the data in image coordinate space. In order to improve upon this situation, ASF's radiometric terrain-correction (RTC) project is generating uniformly formatted and easily accessible value-added products from the ASF Distributed Active Archive Center's (DAAC) five-year archive of JAXA's ALOS PALSAR sensor. Specifically, the project applies geometric and radiometric corrections to SAR data to allow for an easy and direct combination of obliquely acquired SAR data with remote sensing imagery acquired in nadir observation geometries. Finally, the value-added data is provided to the user in the broadly accepted Geotiff format, in order to support the easy integration of SAR data into GIS environments. The goal of ASF's RTC project is to make SAR data more accessible and more attractive to the broader SAR applications community, especially to those users that currently have limited SAR expertise. Production of RTC products commenced October 2014 and will conclude late in 2015. As of July 2015, processing of 71% of ASF's ALOS PALSAR archive was completed. Adding to the utility of this dataset are recent changes to the data access policy that allow the full-resolution RTC products to be provided to the public, without restriction. In this paper we will introduce the processing flow that was developed for the RTC project and summarize the calibration and validation

  8. Numerical Analysis of Orbital Perturbation Effects on Inclined Geosynchronous SAR

    PubMed Central

    Dong, Xichao; Hu, Cheng; Long, Teng; Li, Yuanhao

    2016-01-01

    The geosynchronous synthetic aperture radar (GEO SAR) is susceptible to orbit perturbations, leading to orbit drifts and variations. The influences behave very differently from those in low Earth orbit (LEO) SAR. In this paper, the impacts of perturbations on GEO SAR orbital elements are modelled based on the perturbed dynamic equations, and then, the focusing is analyzed theoretically and numerically by using the Systems Tool Kit (STK) software. The accurate GEO SAR slant range histories can be calculated according to the perturbed orbit positions in STK. The perturbed slant range errors are mainly the first and second derivatives, leading to image drifts and defocusing. Simulations of the point target imaging are performed to validate the aforementioned analysis. In the GEO SAR with an inclination of 53° and an argument of perigee of 90°, the Doppler parameters and the integration time are different and dependent on the geometry configurations. Thus, the influences are varying at different orbit positions: at the equator, the first-order phase errors should be mainly considered; at the perigee and apogee, the second-order phase errors should be mainly considered; at other positions, first-order and second-order exist simultaneously. PMID:27598168

  9. Healthcare Worker Seroconversion in SARS Outbreak

    PubMed Central

    Ooi, Eng-Eong; Tan, Hiang-Khoon; Ong, Kong-Wee; Sil, Bijon Kumar; Teo, Melissa; Ng, Timothy; Soo, Khee-Chee

    2004-01-01

    Serum samples were obtained from healthcare workers 5 weeks after exposure to an outbreak of severe acute respiratory syndrome (SARS). A sensitive dot blot enzyme-linked immunosorbent assay, complemented by a specific neutralization test, shows that only persons in whom probable SARS was diagnosed had specific antibodies and suggests that subclinical SARS is not an important feature of the disease. PMID:15030691

  10. Seismic migration for SAR focusing: Interferometrical applications

    NASA Astrophysics Data System (ADS)

    Prati, C.; Montiguarnieri, A.; Damonti, E.; Rocca, F.

    SAR (Synthetic Aperture Radar) data focusing is analyzed from a theoretical point of view. Two applications of a SAR data processing algorithm are presented, where the phases of the returns are used for the recovery of interesting parameters of the observed scenes. Migration techniques, similar to those used in seismic signal processing for oil prospecting, were implemented for the determination of the terrain altitude map from a satellite and the evaluation of the sensor attitude for an airplane. A satisfying precision was achieved, since it was shown how an interferometric system is able to detect variations of the airplane roll angle of a small fraction of a degree.

  11. Tom Mace and Walter Klein(far right) brief John Danilovich, US Ambassador to Costa Rica, and NASA Administrator Sean O'Keefe onboard NASA's DC-8

    NASA Image and Video Library

    2004-03-03

    Dr. Tom Mace, NASA DFRC Director of Airborne Sciences, and Walter Klein(far right), NASA DFRC Airborne Science Mission Manager, brief John Danilovich, US Ambassador to Costa Rica, and NASA Administrator Sean O'Keefe onboard NASA's DC-8 during a stop-off on the AirSAR 2004 Mesoamerica campaign. AirSAR 2004 Mesoamerica is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

  12. SARS: Safeguards Accounting and Reporting Software

    NASA Astrophysics Data System (ADS)

    Mohammedi, B.; Saadi, S.; Ait-Mohamed, S.

    In order to satisfy the requirements of the SSAC (State System for Accounting and Control of nuclear materials), for recording and reporting objectives; this computer program comes to bridge the gape between nuclear facilities operators and national inspection verifying records and delivering reports. The SARS maintains and generates at-facility safeguards accounting records and generates International Atomic Energy Agency (IAEA) safeguards reports based on accounting data input by the user at any nuclear facility. A database structure is built and BORLAND DELPHI programming language has been used. The software is designed to be user-friendly, to make extensive and flexible management of menus and graphs. SARS functions include basic physical inventory tacking, transaction histories and reporting. Access controls are made by different passwords.

  13. Airborne Windshear Detection and Warning Systems. Fifth and Final Combined Manufacturers' and Technologists' Conference, part 2

    NASA Technical Reports Server (NTRS)

    Delnore, Victor E. (Compiler)

    1994-01-01

    The Fifth Combined Manufacturers' and Technologists' Airborne Windshear Review Meeting was hosted by the NASA Langley Research Center and the Federal Aviation Administration in Hampton, Virginia, on September 28-30, 1993. The purpose was to report on the highly successful windshear experiments conducted by government, academic institutions, and industry; to transfer the results to regulators, manufacturers, and users; and to set initiatives for future aeronautics technology research. The formal sessions covered recent developments in windshear flight testing, windshear modeling, flight management, and ground-based systems, airborne windshear detection systems, certification and regulatory issues, and development and applications of sensors for wake vortices and for synthetic and enhanced vision systems. This report was compiled to record and make available the technology updates and materials from the conference.

  14. 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.

  15. Holographic Airborne Rotating Lidar Instrument Experiment (HARLIE)

    NASA Technical Reports Server (NTRS)

    Schwemmer, Geary K.

    1998-01-01

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

  16. Spaceborne SAR Imaging Algorithm for Coherence Optimized.

    PubMed

    Qiu, Zhiwei; Yue, Jianping; Wang, Xueqin; Yue, Shun

    2016-01-01

    This paper proposes SAR imaging algorithm with largest coherence based on the existing SAR imaging algorithm. The basic idea of SAR imaging algorithm in imaging processing is that output signal can have maximum signal-to-noise ratio (SNR) by using the optimal imaging parameters. Traditional imaging algorithm can acquire the best focusing effect, but would bring the decoherence phenomenon in subsequent interference process. Algorithm proposed in this paper is that SAR echo adopts consistent imaging parameters in focusing processing. Although the SNR of the output signal is reduced slightly, their coherence is ensured greatly, and finally the interferogram with high quality is obtained. In this paper, two scenes of Envisat ASAR data in Zhangbei are employed to conduct experiment for this algorithm. Compared with the interferogram from the traditional algorithm, the results show that this algorithm is more suitable for SAR interferometry (InSAR) research and application.

  17. Spaceborne SAR Imaging Algorithm for Coherence Optimized

    PubMed Central

    Qiu, Zhiwei; Yue, Jianping; Wang, Xueqin; Yue, Shun

    2016-01-01

    This paper proposes SAR imaging algorithm with largest coherence based on the existing SAR imaging algorithm. The basic idea of SAR imaging algorithm in imaging processing is that output signal can have maximum signal-to-noise ratio (SNR) by using the optimal imaging parameters. Traditional imaging algorithm can acquire the best focusing effect, but would bring the decoherence phenomenon in subsequent interference process. Algorithm proposed in this paper is that SAR echo adopts consistent imaging parameters in focusing processing. Although the SNR of the output signal is reduced slightly, their coherence is ensured greatly, and finally the interferogram with high quality is obtained. In this paper, two scenes of Envisat ASAR data in Zhangbei are employed to conduct experiment for this algorithm. Compared with the interferogram from the traditional algorithm, the results show that this algorithm is more suitable for SAR interferometry (InSAR) research and application. PMID:26871446

  18. Water vapor retrieval by LEO and GEO SAR: techniques and performance evaluation.

    NASA Astrophysics Data System (ADS)

    Fermi, Alessandro; Silvio Marzano, Frank; Monti Guarnieri, Andrea; Pierdicca, Nazzareno; Realini, Eugenio; Venuti, Giovanna

    2016-04-01

    The millimetric sensitivity of SAR interferometry has been proved fruitful in estimating water-vapor maps, that can then be processed into higher level ZWD and PWV products. In the paper, we consider two different SAR surveys: Low Earth Orbiting (LEO) SAR, like ESA Sentinel-1, and Geosynchronous Earth Orbiting SAR. The two system are complementary, where LEO coverage is world-wide, while GEO is regional. On the other hand, LEO revisit is daily-to weekly, whereas GEO provides images in minutes to hours. Finally, LEO synthetic aperture is so short, less than a second, that the water-vapor is mostly frozen, whereas in the long GEO aperture the atmospheric phase screen would introduce a total decorrelation, if not compensated for. In the paper, we first review the Differential Interferometric techniques to get differential delay maps - to be then converted into water-vapor products, and then evaluate the quality in terms of geometric resolution, sensitivity, percentage of scene coverage, revisit, by referring to L and C band system, for both LEO and GEO. Finally, we discuss an empirical model for time-space variogram, and show a preliminary validation by campaign conducted with Ground Based Radar, as a proxy of GEO-SAR, capable of continuous scanning wide areas (up to 15 km) with metric resolution.

  19. SAR-based sea traffic monitoring: a reliable approach for maritime surveillance

    NASA Astrophysics Data System (ADS)

    Renga, Alfredo; Graziano, Maria D.; D'Errico, M.; Moccia, A.; Cecchini, A.

    2011-11-01

    Maritime surveillance problems are drawing the attention of multiple institutional actors. National and international security agencies are interested in matters like maritime traffic security, maritime pollution control, monitoring migration flows and detection of illegal fishing activities. Satellite imaging is a good way to identify ships but, characterized by large swaths, it is likely that the imaged scenes contain a large number of ships, with the vast majority, hopefully, performing legal activities. Therefore, the imaging system needs a supporting system which identifies legal ships and limits the number of potential alarms to be further monitored by patrol boats or aircrafts. In this framework, spaceborne Synthetic Aperture Radar (SAR) sensors, terrestrial AIS and the ongoing satellite AIS systems can represent a great potential synergy for maritime security. Starting from this idea the paper develops different designs for an AIS constellation able to reduce the time lag between SAR image and AIS data acquisition. An analysis of SAR-based ship detection algorithms is also reported and candidate algorithms identified.

  20. Recognizing Airborne Hazards.

    ERIC Educational Resources Information Center

    Schneider, Christian M.

    1990-01-01

    The heating, ventilating, and air conditioning (HVAC) systems in older buildings often do not adequately handle air-borne contaminants. Outlines a three-stage Indoor Air Quality (IAQ) assessment and describes a case in point at a Pittsburgh, Pennsylvania, school. (MLF)