Science.gov

Sample records for radar velocity imaging

  1. Tangential Velocity Measurement Using Interferometric MTI Radar

    SciTech Connect

    DOERRY, ARMIN W.; MILESHOSKY, BRIAN P.; BICKEL, DOUGLAS L.

    2002-11-01

    An Interferometric Moving Target Indicator radar can be used to measure the tangential velocity component of a moving target. Multiple baselines, along with the conventional radial velocity measurement, allow estimating the true 3-D velocity vector of a target.

  2. Tangential velocity measurement using interferometric MTI radar

    SciTech Connect

    Doerry, Armin W.; Mileshosky, Brian P.; Bickel, Douglas L.

    2006-01-03

    Radar systems use time delay measurements between a transmitted signal and its echo to calculate range to a target. Ranges that change with time cause a Doppler offset in phase and frequency of the echo. Consequently, the closing velocity between target and radar can be measured by measuring the Doppler offset of the echo. The closing velocity is also known as radial velocity, or line-of-sight velocity. Doppler frequency is measured in a pulse-Doppler radar as a linear phase shift over a set of radar pulses during some Coherent Processing Interval (CPI). An Interferometric Moving Target Indicator (MTI) radar can be used to measure the tangential velocity component of a moving target. Multiple baselines, along with the conventional radial velocity measurement, allow estimating the true 3-D velocity of a target.

  3. Tracking moving radar targets with parallel, velocity-tuned filters

    DOEpatents

    Bickel, Douglas L.; Harmony, David W.; Bielek, Timothy P.; Hollowell, Jeff A.; Murray, Margaret S.; Martinez, Ana

    2013-04-30

    Radar data associated with radar illumination of a movable target is processed to monitor motion of the target. A plurality of filter operations are performed in parallel on the radar data so that each filter operation produces target image information. The filter operations are defined to have respectively corresponding velocity ranges that differ from one another. The target image information produced by one of the filter operations represents the target more accurately than the target image information produced by the remainder of the filter operations when a current velocity of the target is within the velocity range associated with the one filter operation. In response to the current velocity of the target being within the velocity range associated with the one filter operation, motion of the target is tracked based on the target image information produced by the one filter operation.

  4. Material Property Estimation for Direct Detections of DNAPL using Integrated Ground-Penetrating Radar Velocity, Imaging and Attribute Analysis

    SciTech Connect

    Bradford, John; Smithson, Scott B.; Holbrook, W. Stephen

    2004-06-14

    The focus of our work is direct detection of DNAPLs, specifically chlorinated solvents, via material property estimation from surface ground-penetrating radar (GPR) data. We combine sophisticated GPR processing methodology with quantitative attribute analysis and material property estimation to determine the location and extent of residual and/or pooled DNAPL in both the vadose and saturated zones. An important byproduct of our research is state-of-the-art imaging which allows us to pinpoint attribute anomalies, characterize stratigraphy, identify fracture zones, and locate buried objects. Implementation and verification of these methodologies will be a significant advance in GPR research and in meeting DOE's need for reliable in-situ characterization of DNAPL contamination. Chlorinated solvents have much lower electric permittivity and conductivity than water. An electrical property contrast is induced when solvents displace water in the sediment column resulting in an anomalous GPR signature. To directly identify zones of DNAPL contamination, we focus on three aspects of reflected wave behavior--propagation velocity, frequency dependent attenuation, and amplitude variation with offset (AVO). Velocity analysis provides a direct estimate of electric permittivity, attenuation analysis provides a measure of conductivity, and AVO behavior is used to estimate the permittivity ratio at a reflecting boundary. Areas of anomalously low electric permittivity and conductivity are identified as potential DNAPL rich zones. Preliminary work illustrated significant potential for quantitative direct detection methodologies in identifying shallow DNAPL source zones. It is now necessary to verify these methodologies in a field setting. To this end, the project is field oriented and has three primary objectives: (1) Develop a suite of methodologies for direct detection of DNAPLs from surface GPR data (2) Controlled field verification at well characterized, contaminated sites (3

  5. Material Property Estimation for Direct Detection of DNAPL using Integrated Ground-Penetrating Radar Velocity, Imaging and Attribute Analysis

    SciTech Connect

    Bradford, John; Smithson, Scott B.; Holbrook, W. Stephen

    2003-06-01

    The focus of our work is direct detection of DNAPLs, specifically chlorinated solvents, via material property estimation from surface ground-penetrating radar (GPR) data. We combine sophisticated GPR processing methodology with quantitative attribute analysis and material property estimation to determine the location and extent of residual and/or pooled DNAPL in both the vadose and saturated zones. An important byproduct of our research is state-of-the-art imaging which allows us to pinpoint attribute anomalies, characterize stratigraphy, identify fracture zones, and locate buried objects. Implementation and verification of these methodologies will be a significant advance in GPR research and in meeting DOE's need for reliable in-situ characterization of DNAPL contamination. Chlorinated solvents have much lower electric permittivity and conductivity than water. An electrical property contrast is induced when solvents displace water in the sediment column resulting in an anomalous GPR signature. To directly identify zones of DNAPL contamination, we focus on three aspects of reflected wave behavior--propagation velocity, frequency dependent attenuation, and amplitude variation with offset (AVO). Velocity analysis provides a direct estimate of electric permittivity, attenuation analysis provides a measure of conductivity, and AVO behavior is used to estimate the permittivity ratio at a reflecting boundary. Areas of anomalously low electric permittivity and conductivity are identified as potential DNAPL rich zones. Preliminary work illustrated significant potential for quantitative direct detection methodologies in identifying shallow DNAPL source zones. It is now necessary to verify these methodologies in a field setting. To this end, the project is field oriented and has three primary objectives: (1) Develop a suite of methodologies for direct detection of DNAPLs from surface GPR data (2) Controlled field verification at well characterized, contaminated sites (3

  6. Micropower impulse radar imaging

    SciTech Connect

    Hall, M.S.

    1995-11-01

    From designs developed at the Lawrence Livermore National Laboratory (LLNL) in radar and imaging technologies, there exists the potential for a variety of applications in both public and private sectors. Presently tests are being conducted for the detection of buried mines and the analysis of civil structures. These new systems use a patented ultra-wide band (impulse) radar technology known as Micropower Impulse Radar (GPR) imaging systems. LLNL has also developed signal processing software capable of producing 2-D and 3-D images of objects embedded in materials such as soil, wood and concrete. My assignment while at LLNL has focused on the testing of different radar configurations and applications, as well as assisting in the creation of computer algorithms which enable the radar to scan target areas of different geometeries.

  7. Estimating Radar Velocity using Direction of Arrival Measurements

    SciTech Connect

    Doerry, Armin Walter; Horndt, Volker; Bickel, Douglas Lloyd; Naething, Richard M.

    2014-09-01

    Direction of Arrival (DOA) measurements, as with a monopulse antenna, can be compared against Doppler measurements in a Synthetic Aperture Radar ( SAR ) image to determine an aircraft's forward velocity as well as its crab angle, to assist the aircraft's navigation as well as improving high - performance SAR image formation and spatial calibration.

  8. Material Property Estimation for Direct Detection of DNAPL using Integrated Ground-Penetrating Radar Velocity, Imaging and Attribute Analysis

    SciTech Connect

    John H. Bradford; Stephen Holbrook; Scott B. Smithson

    2004-12-09

    The focus of this project is direct detection of DNAPL's specifically chlorinated solvents, via material property estimation from multi-fold surface ground-penetrating radar (GPR) data. We combine state-of-the-art GPR processing methodology with quantitative attribute analysis and material property estimation to determine the location and extent of residual and/or pooled DNAPL in both the vadose and saturated zones. An important byproduct of our research is state-of-the-art imaging which allows us to pinpoint attribute anomalies, characterize stratigraphy, identify fracture zones, and locate buried objects.

  9. Multispectral imaging radar

    NASA Technical Reports Server (NTRS)

    Porcello, L. J.; Rendleman, R. A.

    1972-01-01

    A side-looking radar, installed in a C-46 aircraft, was modified to provide it with an initial multispectral imaging capability. The radar is capable of radiating at either of two wavelengths, these being approximately 3 cm and 30 cm, with either horizontal or vertical polarization on each wavelength. Both the horizontally- and vertically-polarized components of the reflected signal can be observed for each wavelength/polarization transmitter configuration. At present, two-wavelength observation of a terrain region can be accomplished within the same day, but not with truly simultaneous observation on both wavelengths. A multiplex circuit to permit this simultaneous observation has been designed. A brief description of the modified radar system and its operating parameters is presented. Emphasis is then placed on initial flight test data and preliminary interpretation. Some considerations pertinent to the calibration of such radars are presented in passing.

  10. Spaceborne Imaging Radar Symposium

    NASA Technical Reports Server (NTRS)

    Elachi, C.

    1983-01-01

    An overview of the present state of the art in the different scientific and technological fields related to spaceborne imaging radars was presented. The data acquired with the SEASAT SAR (1978) and Shuttle Imaging Radar, SIR-A (1981) clearly demonstrated the important emphasis in the 80's is going to be on in-depth research investigations conducted with the more flexible and sophisticated SIR series instruments and on long term monitoring of geophysical phenomena conducted from free-flying platforms such as ERS-1 and RADARSAT.

  11. Shuttle imaging radar experiment

    USGS Publications Warehouse

    Elachi, C.; Brown, W.E.; Cimino, J.B.; Dixon, T.; Evans, D.L.; Ford, J.P.; Saunders, R.S.; Breed, C.; Masursky, H.; McCauley, J.F.; Schaber, G.; Dellwig, L.; England, A.; MacDonald, H.; Martin-Kaye, P.; Sabins, F.

    1982-01-01

    The shuttle imaging radar (SIR-A) acquired images of a variety of the earth's geologic areas covering about 10 million square kilometers. Structural and geomorphic features such as faults, folds, outcrops, and dunes are clearly visible in both tropical and arid regions. The combination of SIR-A and Seasat images provides additional information about the surface physical properties: topography and roughness. Ocean features were also observed, including large internal waves in the Andaman Sea. Copyright ?? 1982 AAAS.

  12. Radar Imaging of Mercury

    NASA Astrophysics Data System (ADS)

    Harmon, John K.

    2007-10-01

    Earth-based radar has been one of the few, and one of the most important, sources of new information about Mercury during the three decades since the Mariner 10 encounters. The emphasis during the past 15 years has been on full-disk, dual-polarization imaging of the planet, an effort that has been facilitated by the development of novel radar techniques and by improvements in radar systems. Probably the most important result of the imaging work has been the discovery and mapping of radar-bright features at the poles. The radar scattering properties of these features, and their confinement to permanently shaded crater floors, is consistent with volume backscatter from a low-loss volatile such as clean water ice. Questions remain, however, regarding the source and long-term stability of the putative ice, which underscores the need for independent confirmation by other observational methods. Radar images of the non-polar regions have also revealed a plethora of bright features, most of which are associated with fresh craters and their ejecta. Several very large impact features, with rays and other bright ejecta spreading over distances of 1,000 km or more, have been traced to source craters with diameters of 80-125 km. Among these large rayed features are some whose relative faintness suggests that they are being observed in an intermediate stage of degradation. Less extended ray/ejecta features have been found for some of the freshest medium-size craters such as Kuiper and Degas. Much more common are smaller (<40 km diameter) fresh craters showing bright rim-rings but little or no ray structure. These smaller radar-bright craters are particularly common over the H-7 quadrangle. Diffuse areas of enhanced depolarized brightness have been found in the smooth plains, including the circum-Caloris planitiae and Tolstoj Basin. This is an interesting finding, as it is the reverse of the albedo contrast seen between the radar-dark maria and the radar-bright cratered highlands

  13. Radar Imaging of Mercury

    NASA Astrophysics Data System (ADS)

    Harmon, John K.

    Earth-based radar has been one of the few, and one of the most important, sources of new information about Mercury during the three decades since the Mariner 10 encounters. The emphasis during the past 15 years has been on full-disk, dual-polarization imaging of the planet, an effort that has been facilitated by the development of novel radar techniques and by improvements in radar systems. Probably the most important result of the imaging work has been the discovery and mapping of radar-bright features at the poles. The radar scattering properties of these features, and their confinement to permanently shaded crater floors, is consistent with volume backscatter from a low-loss volatile such as clean water ice. Questions remain, however, regarding the source and long-term stability of the putative ice, which underscores the need for independent confirmation by other observational methods. Radar images of the non-polar regions have also revealed a plethora of bright features, most of which are associated with fresh craters and their ejecta. Several very large impact features, with rays and other bright ejecta spreading over distances of 1,000 km or more, have been traced to source craters with diameters of 80-125 km. Among these large rayed features are some whose relative faintness suggests that they are being observed in an intermediate stage of degradation. Less extended ray/ejecta features have been found for some of the freshest medium-size craters such as Kuiper and Degas. Much more common are smaller (<40 km diameter) fresh craters showing bright rim-rings but little or no ray structure. These smaller radar-bright craters are particularly common over the H-7 quadrangle. Diffuse areas of enhanced depolarized brightness have been found in the smooth plains, including the circum-Caloris planitiae and Tolstoj Basin. This is an interesting finding, as it is the reverse of the albedo contrast seen between the radar-dark maria and the radar-bright cratered highlands

  14. Radar Image, Hokkaido, Japan

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The southeast part of the island of Hokkaido, Japan, is an area dominated by volcanoes and volcanic caldera. The active Usu Volcano is at the lower right edge of the circular Lake Toya-Ko and near the center of the image. The prominent cone above and to the left of the lake is Yotei Volcano with its summit crater. The city of Sapporo lies at the base of the mountains at the top of the image and the town of Yoichi -- the hometown of SRTM astronaut Mamoru Mohri -- is at the upper left edge. The bay of Uchiura-Wan takes up the lower center of the image. In this image, color represents elevation, from blue at the lowest elevations to white at the highest. The radar image has been overlaid to provide more details of the terrain. Due to a processing problem, an island in the center of this crater lake is missing and will be properly placed when further SRTM swaths are processed. The horizontal banding in this image is a processing artifact that will be removed when the navigation information collected by SRTM is fully calibrated. This image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC. Size: 100 by 150 kilometers

  15. The Radar Image Generation (RIG) model

    NASA Technical Reports Server (NTRS)

    Stenger, Anthony J.

    1993-01-01

    RIG is a modeling system which creates synthetic aperture radar (SAR) and inverse SAR images from 3-D faceted data bases. RIG is based on a physical optics model and includes the effects of multiple reflections. Both conducting and dielectric surfaces can be modeled; each surface is labeled with a material code which is an index into a data base of electromagnetic properties. The inputs to the program include the radar processing parameters, the target orientation, the sensor velocity, and (for inverse SAR) the target angle rates. The current version of RIG can be run on any workstation, however, it is not a real-time model. We are considering several approaches to enable the program to generate realtime radar imagery. In addition to its image generation function, RIG can also generate radar cross-section (RCS) plots as well as range and doppler radar return profiles.

  16. Imaging synthetic aperture radar

    DOEpatents

    Burns, Bryan L.; Cordaro, J. Thomas

    1997-01-01

    A linear-FM SAR imaging radar method and apparatus to produce a real-time image by first arranging the returned signals into a plurality of subaperture arrays, the columns of each subaperture array having samples of dechirped baseband pulses, and further including a processing of each subaperture array to obtain coarse-resolution in azimuth, then fine-resolution in range, and lastly, to combine the processed subapertures to obtain the final fine-resolution in azimuth. Greater efficiency is achieved because both the transmitted signal and a local oscillator signal mixed with the returned signal can be varied on a pulse-to-pulse basis as a function of radar motion. Moreover, a novel circuit can adjust the sampling location and the A/D sample rate of the combined dechirped baseband signal which greatly reduces processing time and hardware. The processing steps include implementing a window function, stabilizing either a central reference point and/or all other points of a subaperture with respect to doppler frequency and/or range as a function of radar motion, sorting and compressing the signals using a standard fourier transforms. The stabilization of each processing part is accomplished with vector multiplication using waveforms generated as a function of radar motion wherein these waveforms may be synthesized in integrated circuits. Stabilization of range migration as a function of doppler frequency by simple vector multiplication is a particularly useful feature of the invention; as is stabilization of azimuth migration by correcting for spatially varying phase errors prior to the application of an autofocus process.

  17. Radar Imaging and Feature Extraction

    DTIC Science & Technology

    2007-11-02

    aperture radar (ISAR) autofocus and imaging, synthetic aperture radar (SAR) autofocus and motion compensation, superresolution SAR image formation... superresolution image formation, and two parametric methods, MCRELAX (Motion Compensation RELAX) and MCCLEAN (Motion Compensation CLEAN), for simultaneous target...Direction Estimation) together with WRELAX) algorithm is proposed for the superresolution time delay estimation.

  18. A radar image time series

    NASA Technical Reports Server (NTRS)

    Leberl, F.; Fuchs, H.; Ford, J. P.

    1981-01-01

    A set of ten side-looking radar images of a mining area in Arizona that were aquired over a period of 14 yr are studied to demonstrate the photogrammetric differential-rectification technique applied to radar images and to examine changes that occurred in the area over time. Five of the images are rectified by using ground control points and a digital height model taken from a map. Residual coordinate errors in ground control are reduced from several hundred meters in all cases to + or - 19 to 70 m. The contents of the radar images are compared with a Landsat image and with aerial photographs. Effects of radar system parameters on radar images are briefly reviewed.

  19. Shuttle Imaging Radar - Geologic applications

    NASA Technical Reports Server (NTRS)

    Macdonald, H.; Bridges, L.; Waite, W.; Kaupp, V.

    1982-01-01

    The Space Shuttle, on its second flight (November 12, 1981), carried the first science and applications payload which provided an early demonstration of Shuttle's research capabilities. One of the experiments, the Shuttle Imaging Radar-A (SIR-A), had as a prime objective to evaluate the capability of spaceborne imaging radars as a tool for geologic exploration. The results of the experiment will help determine the value of using the combination of space radar and Landsat imagery for improved geologic analysis and mapping. Preliminary analysis of the Shuttle radar imagery with Seasat and Landsat imagery from similar areas provides evidence that spaceborne radars can significantly complement Landsat interpretation, and vastly improve geologic reconnaissance mapping in those areas of the world that are relatively unmapped because of perpetual cloud cover.

  20. Radar Imaging and Target Identification

    DTIC Science & Technology

    2009-02-09

    Methods in Wave Propagation, Vaxjo, Swe- den. • February 19, 2008, "Radar Imaging", math colloquium, Brigham- Young University. • January 31, 2008...manuscript, namely "Radar detection using sparsely distributed 19 apertures in urban environments", Ling Wang, II- Young Son, Trond Varslot, C. Evren...Coinmun. COM- 20, pp. 774-780, 1972. [24] M. Tomlinson, "New automatic equalizer employing modulo arithmetic," Electron. Lett. 7, pp. 138-139, 1971

  1. Radar Image of Galapagos Island

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an image showing part of Isla Isabella in the western Galapagos Islands. It was taken by the L-band radar in HH polarization from the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar on the 40th orbit of the space shuttle Endeavour. The image is centered at about 0.5 degree south latitude and 91 degrees west longitude and covers an area of 75 by 60 kilometers (47 by 37 miles). The radar incidence angle at the center of the image is about 20 degrees.

    The western Galapagos Islands, which lie about 1,200 kilometers (750 miles) west of Ecuador in the eastern Pacific, have six active volcanoes similar to the volcanoes found in Hawaii. Since the time of Charles Darwin's visit to the area in 1835, there have been over 60 recorded eruptions of these volcanoes. This SIR-C/X-SAR image of Alcedo and Sierra Negra volcanoes shows the rougher lava flows as bright features, while ash deposits and smooth pahoehoe lava flows appear dark. A small portion of Isla Fernandina is visible in the extreme upper left corner of the image.

    The Galapagos Islands are one of the SIR-C/X-SAR supersites and data of this area will be taken several times during the flight to allow scientists to conduct topographic change studies and to search for different lava flow types, ash deposits and fault lines.

    Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes

  2. Reducing Spaceborne-Doppler-Radar Rainfall-Velocity Error

    NASA Technical Reports Server (NTRS)

    Tanelli, Simone; Im, Eastwood; Durden, Stephen L.

    2008-01-01

    A combined frequency-time (CFT) spectral moment estimation technique has been devised for calculating rainfall velocity from measurement data acquired by a nadir-looking spaceborne Doppler weather radar system. Prior spectral moment estimation techniques used for this purpose are based partly on the assumption that the radar resolution volume is uniformly filled with rainfall. The assumption is unrealistic in general but introduces negligible error in application to airborne radar systems. However, for spaceborne systems, the combination of this assumption and inhomogeneities in rainfall [denoted non-uniform beam filling (NUBF)] can result in velocity measurement errors of several meters per second. The present CFT spectral moment estimation technique includes coherent processing of a series of Doppler spectra generated in a standard manner from data over measurement volumes that are partially overlapping in the along-track direction. Performance simulation of this technique using high-resolution data from an airborne rain-mapping radar shows that a spaceborne Ku-band Doppler radar operating at signal-to-noise ratios greater than 10 dB can achieve root-mean-square accuracy between 0.5 and 0.6 m/s in vertical-velocity estimates.

  3. Obstacle penetrating dynamic radar imaging system

    DOEpatents

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

    2006-12-12

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

  4. Open Skies Treaty imaging radar technology issues

    NASA Astrophysics Data System (ADS)

    Sandoval, M. B.

    1992-06-01

    This paper discusses the imaging radar technology requirements for the Open Skies regime, including the unresolved issues to be discussed at future Open Skies Consultative Commission (OSCC) meetings. Compliance with international rules on shared technology is addressed and some of the practical considerations for operational deployment of the radar imaging equipment in an Open Skies aircraft are presented. The Open Skies Treaty requirements and validation methodologies for imaging radars that were agreed on and those that will require future OSCC review are discussed.

  5. Doppler effects on velocity spectra observed by MST radars

    NASA Technical Reports Server (NTRS)

    Scheffler, A. O.; Liu, C. H.

    1986-01-01

    Recently, wind data from mesophere-stratosphere-troposphere (MST) radars have been used to study the spectra of gravity waves in the atmosphere (Scheffler and Liu, 1985; VanZandt et al., 1985). Since MST radar measures the line-of-sight Doppler velocities, it senses the components of the wave-associated velocities along its beam directions. These components are related through the polarization relations which depend on the frequency and wave number of the wave. Therfore, the radar-observed velocity spectrum will be different from the original gravity-wave spectrum. Their relationship depends on the frequency and wave number of the wave as well as the propagation geometry. This relation can be used to interpret the observed data. It can also be used to test the assumption of gravity-wave spectrum (Scheffler and Liu, 1985). In deriving this relation, the background atmosphere has been assumed to be motionless. Obviously, the Doppler shift due to the background wind will change the shape of the gravity-wave power spectrum as well as its relation with the radar-observed spectrum. Here, researcher's investigate these changes.

  6. A radar image of Venus.

    NASA Technical Reports Server (NTRS)

    Goldstein, R. M.; Rumsey, H. C.

    1972-01-01

    Radar scans of Venus have yielded a brightness map of a large portion of the surface. The bright area in the south (alpha) and the twin such areas in the north (beta and delta) were first discovered by spectral analysis of radar echos. When range-gating is also applied, their shapes are revealed, and they are seen to be roundish and about 1000 km across. Although radar brightness can be the result of either intrinsic reflectivity or surface roughness, polarization studies show these features to be rough (to the scale of the wavelength, 12.5 cm). Dark, circular areas can also be seen, many with bright central spots. The dark areas are probably smooth. The blurring of the equatorial strip is an artifact of the range-Doppler geometry; all resolution disappears at the equator. Another artifact of the method is the 'ghost', in the south, of the images of beta and delta. Such ghosts appear only at the eastern and western extremes of the map.

  7. Space Radar Image of Bahia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a color composite image of southern Bahia, Brazil, centered at 15.22 degree south latitude and 39.07 degrees west longitude. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar aboard the space shuttle Endeavour on its 38th orbit of Earth on October 2, 1994. The image covers an area centered over the Una Biological Reserve, one the largest protected areas in northeastern Brazil. The 7,000-hectare reserve is administered by the Brazilian Institute for the Environment and is part of the larger Atlantic coastal forest, a narrow band of rain forest extending along the eastern coast of Brazil. The Atlantic coastal forest of southern Bahia is one of the world's most threatened and diverse ecosystems. Due to widespread settlement, only 2 to 5 percent of the original forest cover remains. Yet the region still contains an astounding variety of plants and animals, including a large number of endemic species. More than half of the region's tree species and 80 percent of its animal species are indigenous and found nowhere else on Earth. The Una Reserve is also the only federally protected habitat for the golden-headed lion tamarin, the yellow-breasted capuchin monkey and many other endangered species. In the past few years, scientists from Brazilian and international conservation organizations have coordinated efforts to study the biological diversity of this region and to develop practical and economically viable options for preserving the remaining primary forests in southern Bahia. The shuttle imaging radar is used in this study to identify various land uses and vegetation types, including remaining patches of primary forest, cabruca forest (cacao planted in the understory of the native forest), secondary forest, pasture and coastal mangrove. Standard remote-sensing technology that relies on light reflected from the forest canopy cannot accurately distinguish between cabruca and undisturbed forest. Optical remote sensing is also

  8. Space Radar Image of Bahia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a color composite image of southern Bahia, Brazil, centered at 15.22 degree south latitude and 39.07 degrees west longitude. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar aboard the space shuttle Endeavour on its 38th orbit of Earth on October 2, 1994. The image covers an area centered over the Una Biological Reserve, one the largest protected areas in northeastern Brazil. The 7,000-hectare reserve is administered by the Brazilian Institute for the Environment and is part of the larger Atlantic coastal forest, a narrow band of rain forest extending along the eastern coast of Brazil. The Atlantic coastal forest of southern Bahia is one of the world's most threatened and diverse ecosystems. Due to widespread settlement, only 2 to 5 percent of the original forest cover remains. Yet the region still contains an astounding variety of plants and animals, including a large number of endemic species. More than half of the region's tree species and 80 percent of its animal species are indigenous and found nowhere else on Earth. The Una Reserve is also the only federally protected habitat for the golden-headed lion tamarin, the yellow-breasted capuchin monkey and many other endangered species. In the past few years, scientists from Brazilian and international conservation organizations have coordinated efforts to study the biological diversity of this region and to develop practical and economically viable options for preserving the remaining primary forests in southern Bahia. The shuttle imaging radar is used in this study to identify various land uses and vegetation types, including remaining patches of primary forest, cabruca forest (cacao planted in the understory of the native forest), secondary forest, pasture and coastal mangrove. Standard remote-sensing technology that relies on light reflected from the forest canopy cannot accurately distinguish between cabruca and undisturbed forest. Optical remote sensing is also

  9. Imaging radar polarimetry - A review

    NASA Technical Reports Server (NTRS)

    Zebker, Howard A.; Van Zyl, Jakob J.

    1991-01-01

    The authors present a tutorial review of the broad sweep of topics relating to imaging radar polarimetry, ranging from mathematical foundations to hardware and from implementation approaches to signal processing and calibration. The authors examine current developments in sensor technology and implementation for recording polarimetric measurements, and describe techniques and areas of application for this form of remotely sensed data. Those aspects of ground signal processing and calibration peculiar to the polarimetric signals are addressed. Several of the currently operating instruments and some of the implementations planned for future use are discussed.

  10. Space Radar Image of Chernobyl

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an image of the Chernobyl nuclear power plant and its surroundings, centered at 51.17 north latitude and 30.15 west longitude. The image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar aboard the space shuttle Endeavour on its 16th orbit on October 1, 1994. The area is located on the northern border of the Ukraine Republic and was produced by using the L-band (horizontally transmitted and received) polarization. The differences in the intensity are due to differences in vegetation cover, with brighter areas being indicative of more vegetation. These data were acquired as part of a collaboration between NASA and the National Space Agency of Ukraine in Remote Sensing and Earth Sciences. NASA has included several sites provided by the Ukrainian space agency as targets of opportunity during the second flight of SIR-C/X-SAR. The Ukrainian space agency also plans to conduct airborne surveys of these sites during the mission. The Chernobyl nuclear power plant is located toward the top of the image near the Pripyat River. The 12-kilometer (7.44-mile)-long cooling pond is easily distinguishable as an elongated dark shape in the center near the top of the image. The reactor complex is visible as the bright area to the extreme left of the cooling pond and the city of Chernobyl is the bright area just below the cooling pond next to the Pripyat River. The large dark area in the bottom right of the image is the Kiev Reservoir just north of Kiev. Also visible is the Dnieper River, which feeds into the Kiev Reservoir from the top of the image. The Soviet government evacuated 116,000 people within 30 kilometers (18.6 miles) of the Chernobyl reactor after the explosion and fire on April 26, 1986. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight

  11. Space Radar Image of Long Island Optical/Radar

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This pair of images of the Long Island, New York region is a comparison of an optical photograph (top) and a radar image (bottom), both taken in darkness in April 1994. The photograph at the top was taken by the Endeavour astronauts at about 3 a.m. Eastern time on April 20, 1994. The image at the bottom was acquired at about the same time four days earlier on April 16,1994 by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) system aboard the space shuttle Endeavour. Both images show an area approximately 100 kilometers by 40 kilometers (62 miles by 25 miles) that is centered at 40.7 degrees North latitude and 73.5 degrees West longitude. North is toward the upper right. The optical image is dominated by city lights, which are particularly bright in the densely developed urban areas of New York City located on the left half of the photo. The brightest white zones appear on the island of Manhattan in the left center, and Central Park can be seen as a darker area in the middle of Manhattan. To the northeast (right) of the city, suburban Long Island appears as a less densely illuminated area, with the brightest zones occurring along major transportation and development corridors. Since radar is an active sensing system that provides its own illumination, the radar image shows a great amount of surface detail, despite the night-time acquisition. The colors in the radar image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted and vertically received); blue represents the C-band (horizontally transmitted and vertically received). In this image, the water surface - the Atlantic Ocean along the bottom edge and Long Island Sound shown at the top edge - appears red because small waves at the surface strongly reflect the horizontally transmitted and received L-band radar signal. Networks of highways and railroad lines are clearly

  12. Applications review for a Space Program Imaging Radar (SPIR)

    NASA Technical Reports Server (NTRS)

    Simonett, D. S.

    1976-01-01

    The needs, applications, user support, research, and theoretical studies of imaging radar are reviewed. The applications of radar in water resources, minerals and petroleum exploration, vegetation resources, ocean radar imaging, and cartography are discussed. The advantages of space imaging radar are presented, and it is recommended that imaging radar be placed on the space shuttle.

  13. Passive synthetic aperture radar imaging of ground moving targets

    NASA Astrophysics Data System (ADS)

    Wacks, Steven; Yazici, Birsen

    2012-05-01

    In this paper we present a method for imaging ground moving targets using passive synthetic aperture radar. A passive radar imaging system uses small, mobile receivers that do not radiate any energy. For these reasons, passive imaging systems result in signicant cost, manufacturing, and stealth advantages. The received signals are obtained by multiple airborne receivers collecting scattered waves due to illuminating sources of opportunity such as commercial television, radio, and cell phone towers. We describe a novel forward model and a corresponding ltered-backprojection type image reconstruction method combined with entropy optimization. Our method determines the location and velocity of multiple targets moving at dierent velocities. Furthermore, it can accommodate arbitrary imaging geometries. we present numerical simulations to verify the imaging method.

  14. The Second Spaceborne Imaging Radar Symposium

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Summaries of the papers presented at the Second Spaceborne Imaging Radar Symposium are presented. The purpose of the symposium was to present an overwiew of recent developments in the different scientific and technological fields related to spaceborne imaging radars and to present future international plans.

  15. Spaceborne Imaging Radar-C instrument

    NASA Technical Reports Server (NTRS)

    Huneycutt, Bryan L.

    1993-01-01

    The Spaceborne Imaging Radar-C is the next radar in the series of spaceborne radar experiments, which began with Seasat and continued with SIR-A and SIR-B. The SIR-C instrument has been designed to obtain simultaneous multifrequency and simultaneous multipolarization radar images from a low earth orbit. It is a multiparameter imaging radar that will be flown during at least two different seasons. The instrument operates in the squint alignment mode, the extended aperture mode, the scansar mode, and the interferometry mode. The instrument uses engineering techniques such as beam nulling for echo tracking, pulse repetition frequency hopping for Doppler centroid tracking, generating the frequency step chirp for radar parameter flexibility, block floating-point quantizing for data rate compression, and elevation beamwidth broadening for increasing the swath illumination.

  16. Space Radar Image of Baikal Lake, Russia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an X-band black-and-white image of the forests east of the Baikal Forest in the Jablonowy Mountains of Russia. The image is centered at 52.5 degrees north latitude and 116 degrees east longitude near the mining town of Bukatschatscha. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar aboard the space shuttle Endeavour on October 4, 1994, during the second flight of the spaceborne radar. This area is part of an international research project known as the Taiga Aerospace Investigation using Geographic Information System Applications.

  17. Space radar image of Ubar optical/radar

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This pair of images from space shows a portion of the southern Empty Quarter of the Arabian Peninsula in the country of Oman. On the left is a radar image of the region around the site of the fabled Lost City of Ubar, discovered in 1992 with the aid of remote sensing data. On the right is an enhanced optical image taken by the shuttle astronauts. Ubar existed from about 2800 BC to about 300 AD. and was a remote desert outpost where caravans were assembled for the transport of frankincense across the desert. The actual site of the fortress of the Lost City of Ubar, currently under excavation, is too small to show in either image. However, tracks leading to the site, and surrounding tracks, show as prominent, but diffuse, reddish streaks in the radar image. Although used in modern times, field investigations show many of these tracks were in use in ancient times as well. Mapping of these tracks on regional remote sensing images provided by the Landsat satellite was a key to recognizing the site as Ubar. The prominent magenta colored area is a region of large sand dunes. The green areas are limestone rocks, which form a rocky desert floor. A major wadi, or dry stream bed, runs across the scene and appears as a white line. The radar images, and ongoing field investigations, will help shed light on an early civilization about which little in known. The radar image was taken by the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) and is centered at 18 degrees North latitude and 53 degrees East longitude. The image covers an area about 50 kilometers by 100 kilometers (31 miles by 62 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted, horizontally received; blue is C-band horizontally transmitted, horizontally received; green is L-band horizontally transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian and the United

  18. Space Radar Image of Namibia Sand Dunes

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image shows part of the vast Namib Sand Sea on the west coast of southern Africa, just northeast of the city of Luderitz, Namibia. The magenta areas in the image are fields of sand dunes, and the orange area along the bottom of the image is the surface of the South Atlantic Ocean. The region receives only a few centimeters (inches) of rain per year. In most radar images, sandy areas appear dark due to their smooth texture, but in this area the sand is organized into steep dunes, causing bright radar reflections off the dune 'faces.' This effect is especially pronounced in the lower center of the image, where many glints of bright radar reflections are seen. Radar images of this hyper-arid region have been used to image sub-surface features, such as abandoned stream courses. The bright green features in the upper right are rocky hills poking through the sand sea. The peninsula in the lower center, near Hottentott Bay, is Diaz Point; Elizabeth Point is south of Diaz Point. This image was acquired by Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on April 11, 1994. The image is 54.2 kilometers by 82.2 kilometers (33.6 miles by 51.0 miles) and is centered at 26.2 degrees South latitude, 15.1 degrees East longitude. North is toward the upper left. The colors are assigned to different radar frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted and received; green is L-band, horizontally transmitted, vertically received; and blue is C-band, horizontally transmitted, horizontally received. SIR-C/X-SAR, a joint mission of the German, Italian, and United States space agencies, is part of NASA's Mission to Planet Earth.

  19. APQ-102 imaging radar digital image quality study

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    A modified APQ-102 sidelooking radar collected synthetic aperture radar (SAR) data which was digitized and recorded on wideband magnetic tape. These tapes were then ground processed into computer compatible tapes (CCT's). The CCT's may then be processed into high resolution radar images by software on the CYBER computer.

  20. Radar image of Rio Sao Francisco, Brazil

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This radar image acquired by SRTM shows an area south of the Sao Francisco River in Brazil. The area is predominantly scrub forest. Areas such as these are difficult to map by traditional methods because of frequent cloud cover and local inaccessibility. Image brightness differences in this image are caused by differences in vegetation type and density. Tributaries of the Sao Francisco are visible in the upper right. The Sao Francisco River is a major source of water for irrigation and hydroelectric power. Mapping such regions will allow scientists to better understand the relationships between flooding cycles, forestation and human influences on ecosystems.

    This radar image was obtained by the Shuttle Radar Topography Mission as part of its mission to map the Earth's topography. The image was acquired by just one of SRTM's two antennas, and consequently does not show topographic data but only the strength of the radar signal reflected from the ground. This signal, known as radar backscatter, provides insight into the nature of the surface, including its roughness, vegetation cover, and urbanization.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.

  1. Space Radar Image of Munich, Germany

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image of Munich, Germany illustrates the capability of a multi-frequency radar system to highlight different land use patterns in the area surrounding Bavaria's largest city. Central Munich is the white area at the middle of the image, on the banks of the Isar River. Pink areas are forested, while green areas indicate clear-cut and agricultural terrain. The Munich region served as a primary 'supersite' for studies in ecology, hydrology and radar calibration during the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) missions. Scientists were able to use these data to map patterns of forest damage from storms and areas affected by bark beetle infestation. The image was acquired by SIR-C/X-SAR onboard the space shuttle Endeavour on April 18, 1994. The image is 37 kilometers by 32 kilometers (23 miles by 20 miles) and is centered at 48.2 degrees North latitude, 11.5 degrees East longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations of the radar as follows: red is L-band, vertically transmitted and horizontally received; green is C-band, vertically transmitted and horizontally received; and blue is C-band vertically transmitted and received. SIR-C/X-SAR, a joint mission of the German, Italian, and United States space agencies, is part of NASA's Mission to Planet Earth.

  2. Imaging radar observations of Askja Caldera, Iceland

    NASA Technical Reports Server (NTRS)

    Malin, M. C.; Evans, D.; Elachi, C.

    1978-01-01

    A 'blind' test involving interpretation of computer-enhanced like- and cross-polarized radar images is used to evaluate the surface roughness of Askja Caldera, a large volcanic complex in central Iceland. The 'blind' test differs from earlier analyses of radar observations in that computer-processes images and both qualitative and quantitative analyses are used. Attention is given to photogeologic examination and subsequent survey-type field observations, along with aerial photography during the field trip. The results indicate that the 'blind' test of radar interpretation of the Askja volcanic area can be considered suitable within the framework of limitations of radar data considered explicitly from the onset. The limitations of the radar techniques can be eliminated by using oblique-viewing conditions to remove geometric distortions and slope effects.

  3. Comparison of various enhanced radar imaging techniques

    NASA Astrophysics Data System (ADS)

    Gupta, Inder J.; Gandhe, Avinash

    1998-09-01

    Recently, many techniques have been proposed to enhance the quality of radar images obtained using SAR and/or ISAR. These techniques include spatially variant apodization (SVA), adaptive sidelobe reduction (ASR), the Capon method, amplitude and phase estimation of sinusoids (APES) and data extrapolation. SVA is a special case of ASR; whereas the APES algorithm is similar to the Capon method except that it provides a better amplitude estimate. In this paper, the ASR technique, the APES algorithm and data extrapolation are used to generate radar images of two experimental targets and an airborne target. It is shown that although for ideal situations (point targets) the APES algorithm provides the best radar images (reduced sidelobe level and sharp main lobe), its performance degrades quickly for real world targets. The ASR algorithm gives radar images with low sidelobes but at the cost of some loss of information about the target. Also, there is not much improvement in radar image resolution. Data extrapolation, on the other hand, improves image resolution. In this case one can reduce the sidelobes by using non-uniform weights. Any loss in the radar image resolution due to non-uniform weights can be compensated by further extrapolating the scattered field data.

  4. Space Radar Image of Randonia Rain Cell

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This multi-frequency space radar image of a tropical rainforest in western Brazil shows rapidly changing land use patterns and it also demonstrates the capability of the different radar frequencies to detect and penetrate heavy rainstorms. This color image was created by combining the three separate radar frequencies into a composite image. The three black and white images below represent the individual frequencies. The lower left image, X-band vertically transmitted and received, is blue in the color image; the lower center image, C-band horizontally transmitted and vertically received is green; and the lower right image, L-band horizontally transmitted and vertically received is red. A heavy downpour in the lower center of the image appears as a black 'cloud' in the X-band image, the same area is shows up faintly in the C-band image, and is invisible in the L-band image. When combined in the color image, the rain cell appears red and yellow. Although radar can usually 'see' through clouds, short radar wavelengths (high frequency), such as X and C-band, can be changed by unusually heavy rain cells. L-band, at a 24 cm (9 inches) wavelength, is unaffected by such rain cells. By analyzing the way the radar changes, scientist can estimate rainfall rates. The area shown is in the state of Rondonia, in western Brazil. The pink areas are pristine tropical rainforest, and the blue and green patches are areas where the forest has been cleared for agriculture. Cleared areas are typically able to support intense farming for a only few years, before soil erosion renders the fields unusable. Radar imaging can be used to monitor not only the rainforest destruction, but also the rates of recovery of abandoned fields. This image is 35.2 kilometers by 21.3 kilometers (21.8 miles by 13.2 miles) and is centered at 11.2 degrees south latitude, 61.7 degrees west longitude. North is toward the upper left. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic

  5. Jamming cancellation algorithm for wideband imaging radar

    NASA Astrophysics Data System (ADS)

    Zheng, Yibin; Yu, Kai-Bor

    1998-10-01

    We describe a jamming cancellation algorithm for wide-band imaging radar. After reviewing high range resolution imaging principle, several key factors affecting jamming cancellation performances, such as the 'instantaneous narrow-band' assumption, bandwidth, de-chirped interference, are formulated and analyzed. Some numerical simulation results, using a hypothetical phased array radar and synthetic point targets, are presented. The results demonstrated the effectiveness of the proposed algorithm.

  6. Space radar image of Mount Everest

    NASA Technical Reports Server (NTRS)

    1995-01-01

    These are two comparison images of Mount Everest and its surroundings, along the border of Nepal and Tibet. The peak of Mount Everest, the highest elevation on Earth at 8,848 meters (29,028 feet), can be seen near the center of each image. The image at the top was acquired through thick cloud cover by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on April 16, 1994. The image on the bottom is an optical photograph taken by the Endeavour crew under clear conditions during the second flight of SIR-C/X-SAR on October 10, 1994. Both images show an area approximately 70 kilometers by 38 kilometers (43 miles by 24 miles) that is centered at 28.0 degrees north latitude and 86.9 degrees east longitude. North is toward the upper left. The colors in the radar image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted and vertically received); blue represents the C-band (horizontally transmitted and vertically received). Radar illumination is from the top of the frame. The optical photograph has been geometrically adjusted to better match the area shown in the radar image. Many features of the Himalayan terrain are visible in both images. Snow covered areas appear white in the optical photograph while the same areas appear bright blue in the radar image. The radar image was taken in early spring and shows deep snow cover, while the optical photograph was taken in late summer and shows minimum snow cover. The curving and branching features seen in both images are glaciers. The two wavelengths and multiple polarizations of the SIR-C radar are sensitive to characteristics of the glacier surfaces that are not detected by conventional photography, such as the ice roughness, water content and stratification. For this reason, the glaciers show a variety of colors in the radar image (blue, purple, red

  7. Feature utility in polarimetric radar image classification

    NASA Technical Reports Server (NTRS)

    Cumming, Ian G.; Van Zyl, Jakob J.

    1989-01-01

    The information content in polarimetric SAR images is examined, and the polarimetric image variables containing the information that is important to the classification of terrain features in the images are determined. It is concluded that accurate classification can be done when just over half of the image variables are retained. A reduction in image data dimensionality gives storage savings, and can lead to the improvement of classifier performance. In addition, it is shown that a simplified radar system with only phase-calibrated CO-POL or SINGLE TX channels can give classification performance which approaches that of a fully polarimetric radar.

  8. Space Radar Image of Phnom Phen, Cambodia

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This spaceborne radar image shows the city of Phnom Penh, the capital of Cambodia. Phnom Penh lies at the confluence of the Mekong River and the Basak Sab. The city was originally established in 1434 to succeed Angkor Thom as capital of the Khmer Nation. Phnom Penh is the bright blue and orange area west of the rivers, near the center of the image. The red, light blue and purple colors indicate differences in vegetation height and structure. Radar images like this one are being used by archaeologists to investigate ruins in the Angkor area in northern Cambodia. This image was acquired by Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on April 15, 1994. The image is 27 kilometers by 27 kilometers (17 miles by 17 miles) and is centered at 11.5 degrees north latitude, 105.0 degrees East longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted and received; green is L-band, horizontally transmitted and vertically received; and blue is C-band, horizontally transmitted and vertically received. SIR-C/X-SAR, a joint mission of the German, Italian, and United States space agencies, is part of NASA's Mission to Planet Earth.

  9. Radar images analysis for scattering surfaces characterization

    NASA Astrophysics Data System (ADS)

    Piazza, Enrico

    1998-10-01

    According to the different problems and techniques related to the detection and recognition of airplanes and vehicles moving on the Airport surface, the present work mainly deals with the processing of images gathered by a high-resolution radar sensor. The radar images used to test the investigated algorithms are relative to sequence of images obtained in some field experiments carried out by the Electronic Engineering Department of the University of Florence. The radar is the Ka band radar operating in the'Leonardo da Vinci' Airport in Fiumicino (Rome). The images obtained from the radar scan converter are digitized and putted in x, y, (pixel) co- ordinates. For a correct matching of the images, these are corrected in true geometrical co-ordinates (meters) on the basis of fixed points on an airport map. Correlating the airplane 2-D multipoint template with actual radar images, the value of the signal in the points involved in the template can be extracted. Results for a lot of observation show a typical response for the main section of the fuselage and the wings. For the fuselage, the back-scattered echo is low at the prow, became larger near the center on the aircraft and than it decrease again toward the tail. For the wings the signal is growing with a pretty regular slope from the fuselage to the tips, where the signal is the strongest.

  10. Space radar image of Wadi Kufra, Libya

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The ability of a sophisticated radar instrument to image large regions of the world from space, using different frequencies that can penetrate dry sand cover, produced the discovery in this image: a previously unknown branch of an ancient river, buried under thousands of years of windblown sand in a region of the Sahara Desert in North Africa. This area is near the Kufra Oasis in southeast Libya, centered at 23.3 degrees north latitude, 22.9 degrees east longitude. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture (SIR-C/X-SAR) imaging radar when it flew aboard the space shuttle Endeavour on its 60th orbit on October 4, 1994. This SIR-C image reveals a system of old, now inactive stream valleys, called 'paleodrainage systems,

  11. NASA Radar Images Asteroid Toutatis

    NASA Video Gallery

    This 64-frame movie of asteroid Toutatis was generated from data by Goldstone's Solar System Radar on Dec. 12 and 13, 2012. In the movie clips, the rotation of the asteroid appears faster than it o...

  12. Measurements of vertical velocity over flat terrain by ST radar and other related uses of the radar data set

    NASA Technical Reports Server (NTRS)

    Green, J. L.; Nastrom, G. D.

    1984-01-01

    The need to study vertical velocity measurements from an ST radar located on the plains, far from the mountains is pointed out, as all presently available clear-air radars are located in or near mountains. The construction and operation of a VHF Doppler (ST) radar in the midwestern part of the United States to make meteorological measurements is also discussed. While primary interest is in measuring the synoptic-scale vertical velocities in the troposphere and lower stratosphere, it should be stressed, however, that the radar data set generated during the radar experiment would have many other valuable uses of interest to us and others some of whom are listed below. The required radar parameters, approximate costs, and recommended mode of operation are also detailed.

  13. space Radar Image of Long Valley, California

    NASA Technical Reports Server (NTRS)

    1994-01-01

    An area near Long Valley, California, was mapped by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar aboard the space shuttle Endeavor on April 13, 1994, during the first flight of the radar instrument, and on October 4, 1994, during the second flight of the radar instrument. The orbital configurations of the two data sets were ideal for interferometric combination -- that is overlaying the data from one image onto a second image of the same area to create an elevation map and obtain estimates of topography. Once the topography is known, any radar-induced distortions can be removed and the radar data can be geometrically projected directly onto a standard map grid for use in a geographical information system. The 50 kilometer by 50 kilometer (31 miles by 31 miles) map shown here is entirely derived from SIR-C L-band radar (horizontally transmitted and received) results. The color shown in this image is produced from the interferometrically determined elevations, while the brightness is determined by the radar backscatter. The map is in Universal Transverse Mercator (UTM) coordinates. Elevation contour lines are shown every 50 meters (164 feet). Crowley Lake is the dark feature near the south edge of the map. The Adobe Valley in the north and the Long Valley in the south are separated by the Glass Mountain Ridge, which runs through the center of the image. The height accuracy of the interferometrically derived digital elevation model is estimated to be 20 meters (66 feet) in this image. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global

  14. Radar Imaging with a Network of Digital Noise Radar Systems

    DTIC Science & Technology

    2009-03-01

    by the name of Dr. Ross became interested in describing the transient response of a type of microwave network through its characteristic impulse...Professor Peter ... Collins. %The code has been slightly modified since its orginal creation. %% Form image from arbitrary number of radar units % [img ,ximg... RESPONSIBLE PERSON 19b. TELEPHONE NUMBER (include area code ) Standard Form 298 (Rev. 8–98) Prescribed by ANSI Std. Z39.18 12–03–2009 Master’s Thesis Sept

  15. Space Radar Image of Wenatchee, Washington

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image shows a segment of the Columbia River as it passes through the area of Wenatchee, Washington, about 220 kilometers (136 miles) east of Seattle. The Wenatchee Mountains, part of the Cascade Range, are shown in green at the lower left of the image. The Cascades create a 'rain shadow' for the region, limiting rainfall east of the range to less than 26 centimeters (10 inches) per year. The radar's ability to see different types of vegetation is highlighted in the contrast between the pine forests, that appear in green and the dry valley plain that shows up as dark purple. The cities of Wenatchee and East Wenatchee are the grid-like areas straddling the Columbia River in the left center of the image. With a population of about 60,000, the region produces about half of Washington state's lucrative apple crop. Several orchard areas appear as green rectangular patches to the right of the river in the lower right center. Radar images such as these can be used to monitor land use patterns in areas such as Wenatchee, that have diverse and rapidly changing urban, agricultural and wild land pressures. This image was acquired by Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on October 10, 1994. The image is 38 kilometers by 45 kilometers (24 miles by 30 miles) and is centered at 47.3 degrees North latitude, 120.1 degrees West longitude. North is toward the upper left. The colors are assigned to different radar frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted and received; green is L-band, horizontally transmitted, vertically received; and blue is C-band, horizontally transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian, and United States space agencies, is part of NASA's Mission to Planet Earth.

  16. Space radar image of New York City

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This radar image of the New York city metropolitan area. The island of Manhattan appears in the center of the image. The green-colored rectangle on Manhattan is Central Park. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/ X-SAR) aboard the space shuttle Endeavour on October 10, 1994. North is toward the upper right. The area shown is 75.0 kilometers by 48.8 kilometers (46.5 miles by 30.2 miles). The image is centered at 40.7 degrees north latitude and 73.8 degrees west longitude. In general, light blue areas correspond to dense urban development, green areas to moderately vegetated zones and black areas to bodies of water. The Hudson River is the black strip that runs from the left edge to the upper right corner of the image. It separates New Jersey, in the upper left of the image, from New York. The Atlantic Ocean is at the bottom of the image where two barrier islands along the southern shore of Long Island are also visible. John F. Kennedy International Airport is visible above these islands. Long Island Sound, separating Long Island from Connecticut, is the dark area right of the center of the image. Many bridges are visible in the image, including the Verrazano Narrows, George Washington and Brooklyn bridges. The radar illumination is from the left of the image; this causes some urban zones to appear red because the streets are at a perpendicular angle to the radar pulse. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted, vertically received); blue represents the C-band (horizontally transmitted, vertically received). Radar images like this one could be used as a tool for city planners and resource managers to map and monitor land use patterns. The radar imaging systems can clearly detect the variety of landscapes in the area, as well as the density of urban

  17. Space Radar Image of North Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a radar image showing surface features on the open ocean in the northeast Atlantic Ocean. There is no land mass in this image. The purple line in the lower left of the image is the stern wake of a ship. The ship creating the wake is the bright white spot on the middle, left side of the image. The ship's wake is about 28 kilometers (17 miles) long in this image and investigators believe that is because the ship may be discharging oil. The oil makes the wake last longer and causes it to stand out in this radar image. A fairly sharp boundary or front extends from the lower left to the upper right corner of the image and separates two distinct water masses that have different temperatures. The different water temperature affects the wind patterns on the ocean. In this image, the light green area depicts rougher water with more wind, while the purple area is calmer water with less wind. The dark patches are smooth areas of low wind, probably related to clouds along the front, and the bright green patches are likely due to ice crystals in the clouds that scatter the radar waves. The overall 'fuzzy' look of this image is caused by long ocean waves, also called swells. Ocean radar imagery allows the fine detail of ocean features and interactions to be seen, such as the wake, swell, ocean front and cloud effects, which can then be used to enhance the understanding of ocean dynamics on smaller and smaller scales. The image is centered at 42.8 degrees north latitude, 26.2 degrees west longitude and shows an area approximately 35 kilometers by 65 kilometers (22 by 40 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, horizontally received; green is C-band horizontally transmitted, horizontally received; blue is L-band vertically transmitted, vertically received. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR

  18. Space Radar Image of Central Sumatra, Indonesia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a radar image of the central part of the island of Sumatra in Indonesia that shows how the tropical rainforest typical of this country is being impacted by human activity. Native forest appears in green in this image, while prominent pink areas represent places where the native forest has been cleared. The large rectangular areas have been cleared for palm oil plantations. The bright pink zones are areas that have been cleared since 1989, while the dark pink zones are areas that were cleared before 1989. These radar data were processed as part of an effort to assist oil and gas companies working in the area to assess the environmental impact of both their drilling operations and the activities of the local population. Radar images are useful in these areas because heavy cloud cover and the persistent smoke and haze associated with deforestation have prevented usable visible-light imagery from being acquired since 1989. The dark shapes in the upper right (northeast) corner of the image are a chain of lakes in flat coastal marshes. This image was acquired in October 1994 by the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour. Environmental changes can be easily documented by comparing this image with visible-light data that were acquired in previous years by the Landsat satellite. The image is centered at 0.9 degrees north latitude and 101.3 degrees east longitude. The area shown is 50 kilometers by 100 kilometers (31 miles by 62 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, horizontally received; green is L-band horizontally transmitted, vertically received; blue is L-band vertically transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  19. Space Radar Image of Los Angeles, California

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This radar image shows the massive urbanization of Los Angeles, California. The image extends from the Santa Monica Bay at the left to the San Gabriel Mountains at the right. Downtown Los Angeles is in the center of the image. The runways of the Los Angeles International Airport appear as black strips at the left center of the image. The waterways of Marina del Rey are seen just above the airport. The San Gabriel Mountains and the city of Pasadena are at the right center of the image. Black areas on the mountains on the right are fire scars from the 1993 Altadena fire. The Rose Bowl is shown as a small circle near the right center. The complex freeway system is visible as dark lines throughout the image. Some city areas, such as Santa Monica in the upper left, appear red due to the alignment of streets and buildings to the incoming radar beam. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on October 3, 1994. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. This image is centered at 34.04 degrees North latitude and 118.2 degrees West longitude with North pointing toward the upper right. The area shown measures 40 kilometers by 50 kilometers (25 miles by 31 miles).

  20. Spaceborne imaging radar - Geologic and oceanographic applications

    NASA Technical Reports Server (NTRS)

    Elachi, C.

    1980-01-01

    Synoptic, large-area radar images of the earth's land and ocean surface, obtained from the Seasat orbiting spacecraft, show the potential for geologic mapping and for monitoring of ocean surface patterns. Structural and topographic features such as lineaments, anticlines, folds and domes, drainage patterns, stratification, and roughness units can be mapped. Ocean surface waves, internal waves, current boundaries, and large-scale eddies have been observed in numerous images taken by the Seasat imaging radar. This article gives an illustrated overview of these applications.

  1. Space Radar Image of Owens Valley, California

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a three-dimensional perspective view of Owens Valley, near the town of Bishop, California that was created by combining two spaceborne radar images using a technique known as interferometry. Visualizations like this one are helpful to scientists because they clarify the relationships of the different types of surfaces detected by the radar and the shapes of the topographic features such as mountains and valleys. The view is looking southeast along the eastern edge of Owens Valley. The White Mountains are in the center of the image, and the Inyo Mountains loom in the background. The high peaks of the White Mountains rise more than 3,000 meters (10,000 feet) above the valley floor. The runways of the Bishop airport are visible at the right edge of the image. The meandering course of the Owens River and its tributaries appear light blue on the valley floor. Blue areas in the image are smooth, yellow areas are rock outcrops, and brown areas near the mountains are deposits of boulders, gravel and sand known as alluvial fans. The image was constructed by overlaying a color composite radar image on top of a digital elevation map. The radar data were taken by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on board the space shuttle Endeavour in October 1994. The digital elevation map was produced using radar interferometry, a process in which radar data are acquired on different passes of the space shuttle. The two data passes are compared to obtain elevation information. The elevation data were derived from a 1,500-km-long (930-mile) digital topographic map processed at JPL. Radar image data are draped over the topography to provide the color with the following assignments: red is L-band vertically transmitted, vertically received; green is C-band vertically transmitted, vertically received; and blue is the ratio of C-band vertically transmitted, vertically received to L-band vertically transmitted, vertically received. This image is

  2. Space Radar Image of Samara, Russia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This three-frequency space radar image shows the city of Samara, Russia in pink and light green right of center. Samara is at the junction of the Volga and Samara Rivers approximately 800 kilometers (500 miles) southeast of Moscow. The wide river in the center of the image is the Volga. Samara, formerly Kuybyshev, is a busy industrial city known for its chemical, mechanical and petroleum industries. Northwest of the Volga (upper left corner of the image) are deciduous forests of the Samarskaya Luka National Park. Complex patterns in the floodplain of the Volga are caused by 'cut-off' lakes and channels from former courses of the meandering river. The three radar frequencies allow scientists to distinguish different types of agricultural fields in the lower right side of the image. For example, fields which appear light blue are short grass or cleared fields. Purple and green fields contain taller plants or rough plowed soil. Scientists hope to use radar data such as these to understand the environmental consequences of industrial, agricultural and natural preserve areas coexisting in close proximity. This image is 50 kilometers by 26 kilometers (31 by 16 miles) and is centered at 53.2 degrees north latitude, 50.1 degrees east longitude. North is toward the top of the image. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontally transmitted and vertically received; and blue is X-band, vertically transmitted and received. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on October 1, 1994 onboard the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth.

  3. Space Radar Image of Mineral Resources, China

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image of a mineral-rich region in southern China is being used by geologists to identify potential new areas for mineral exploration. The area shown is the vicinity of the city of Zhao Qing, the light blue area along the banks of the River Xi Jiang in the lower left. This is in the southern Chinese province of Guangdong, about 75 kilometers (46 miles) west of Guangzhou (Canton). The largest gold mine in southern China is located in the far upper left of the image along a brightly reflective mountain ridge. Using the radar image as a guide, geologists are tracing the extension of the ridge structure to the east (right) to identify possible mining areas. Radar imaging is especially useful for this purpose because of its sensitivity to subtle topographic structure, even in areas such as these, which have a dense vegetation cover. The Xi Jiang area is one of the most productive mining regions in China, with deposits of tungsten, lead, zinc and gold. The image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttleEndeavour on April 17, 1994. The image is centered at 37.2 degreesnorth latitude and 112.5 degrees east longitude. North is toward the upper right. The image shows an area 60 kilometers by 38 kilometers (37.2 miles by 23.6 miles) The colors are assigned to different frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted, horizontally received; green is L-band, horizontally transmitted, vertically received; blue is C-band, horizontally transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earthprogram.

  4. Using doppler radar images to estimate aircraft navigational heading error

    SciTech Connect

    Doerry, Armin W; Jordan, Jay D; Kim, Theodore J

    2012-07-03

    A yaw angle error of a motion measurement system carried on an aircraft for navigation is estimated from Doppler radar images captured using the aircraft. At least two radar pulses aimed at respectively different physical locations in a targeted area are transmitted from a radar antenna carried on the aircraft. At least two Doppler radar images that respectively correspond to the at least two transmitted radar pulses are produced. These images are used to produce an estimate of the yaw angle error.

  5. Space Radar Image of Safsaf Oasis, Egypt

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This three-frequency space radar image of south-central Egypt demonstrates the unique capability of imaging radar to penetrate thin sand cover in arid regions to reveal hidden details below the surface. Nearly all of the structures seen in this image are invisible to the naked eye and to conventional optical satellite sensors. Features appear in various colors because the three separate radar wavelengths are able to penetrate the sand to different depths. Areas that appear red or orange are places that can be seen only by the longest wavelength, L-band, and they are the deepest of the buried structures. Field studies in this area indicate L-band can penetrate as much as 2 meters (6.5 feet) of very dry sand to image buried rock structures. Ancient drainage channels at the bottom of the image are filled with sand more than 2 meters (6.5 feet) thick and therefore appear dark because the radar waves cannot penetrate them. The fractured orange areas at the top of the image and the blue circular structures in the center of the image are granitic areas that may contain mineral ore deposits. Scientists are using the penetrating capabilities of radar imaging in desert areas in studies of structural geology, mineral exploration, ancient climates, water resources and archaeology. This image is 51.9 kilometers by 30.2 kilometers (32.2 miles by 18.7 miles) and is centered at 22.7 degrees north latitude, 29.3degrees east longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontally transmitted and received; and blue is X-band, vertically transmitted and received. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on April 16, 1994, on board the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission

  6. Space Radar Image of Saline Valley, California

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a three-dimensional perspective view of Saline Valley, about 30 km (19 miles) east of the town of Independence, California created by combining two spaceborne radar images using a technique known as interferometry. Visualizations like this one are helpful to scientists because they clarify the relationships of the different types of surfaces detected by the radar and the shapes of the topographic features such as mountains and valleys. The view is looking southwest across Saline Valley. The high peaks in the background are the Inyo Mountains, which rise more than 3,000 meters (10,000 feet) above the valley floor. The dark blue patch near the center of the image is an area of sand dunes. The brighter patches to the left of the dunes are the dry, salty lake beds of Saline Valley. The brown and orange areas are deposits of boulders, gravel and sand known as alluvial fans. The image was constructed by overlaying a color composite radar image on top of a digital elevation map. The radar image was taken by the Spaceborne Imaging Radar-C/X-bandSynthetic Aperture Radar (SIR-C/X-SAR) on board the space shuttleEndeavour in October 1994. The digital elevation map was producedusing radar interferometry, a process in which radar data are acquired on different passes of the space shuttle. The two data passes are compared to obtain elevation information. The elevation data were derived from a 1,500-km-long (930-mile) digital topographic map processed at JPL. Radar image data are draped over the topography to provide the color with the following assignments: red is L-band vertically transmitted, vertically received; green is C-band vertically transmitted, vetically received; and blue is the ratio of C-band vertically transmitted, vertically received to L-band vertically transmitted, vertically received. This image is centered near 36.8 degrees north latitude and 117.7 degrees west longitude. No vertical exaggeration factor has been applied to the data. SIR-C/X-SAR, a joint

  7. Space radar image of Galeras Volcano, Colombia

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This radar image of the area surrounding the Galeras volcano in southern Colombia shows the ability of a multi-frequency radar to map volcanic structures that can be dangerous to study on the ground. Galeras has erupted more than 20 times since the area was first visited by European explorers in the 1500s. Volcanic activity levels have been high in the last five years, including an eruption in January 1993 that killed nine people on a scientific expedition to the volcano summit. Galeras is the light green area near the center of the image. The active cone, with a small summit pit, is the red feature nestled against the lower right edge of the caldera (crater) wall. The city of Pasto, with a population of 300,000, is shown in orange near the bottom of the image, just 8 kilometers (5 miles) from the volcano. The image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/ X-SAR) aboard the space shuttle Endeavour on its 96th orbit on April 15, 1994. North is toward the upper right. The area shown is 49.1 by 36.0 kilometers (30.5 by 22.3 miles), centered at 1.2 degrees north latitude and 77.4 degrees west longitude. The radar illumination is from the top of the image. The false colors in this image were created using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted, vertically received); blue represents the C-band (horizontally transmitted, vertically received). Galeras is one of 15 volcanoes worldwide that are being monitored by the scientific community as an 'International Decade Volcano' because of the hazard that it represents to the local population.

  8. Space Radar Image of Star City, Russia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This radar image shows the Star City cosmonaut training center, east of Moscow, Russia. Four American astronauts are training here for future long-duration flights aboard the Russian Mir space station. These joint flights are giving NASA and the Russian Space Agency experience necessary for the construction of the international Alpha space station, beginning in late 1997. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR), on its 62nd orbit on October 3, 1994. This Star City image is centered at 55.55 degrees north latitude and 38.0 degrees east longitude. The area shown is approximately 32 kilometers by 49 kilometers (20 miles by 30 miles). North is to the top in this image. The radar illumination is from the top of the image. The image was produced using three channels of SIR-C radar data: red indicates L-band (23 cm wavelength, horizontally transmitted and received); green indicates L-band (horizontally transmitted and vertically received); blue indicates C-band (6 cm wavelength, horizontally transmitted and vertically received). In general, dark pink areas are agricultural; pink and light blue areas are urban communities; black areas represent lakes and rivers; dark blue areas are cleared forest; and light green areas are forested. The prominent black runways just right of center are Shchelkovo Airfield, about 4 km long. The textured pale blue-green area east and southeast of Shchelkovo Airfield is forest. Just east of the runways is a thin railroad line running southeast; the Star City compound lies just east of the small bend in the rail line. Star City contains the living quarters and training facilities for Russian cosmonauts and their families. Moscow's inner loop road is visible at the lower left edge of the image. The Kremlin is just off the left edge, on the banks of the meandering Moskva River. The Klyazma River snakes to the southeast from the reservoir in the upper left (shown in bright red

  9. Space Radar Image of San Francisco, California

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a radar image of San Francisco, California, taken on October 3,1994. The image is about 40 kilometers by 55 kilometers (25 miles by 34 miles) with north toward the upper right. Downtown San Francisco is visible in the center of the image with the city of Oakland east (to the right) across San Francisco Bay. Also visible in the image is the Golden Gate Bridge (left center) and the Bay Bridge connecting San Francisco and Oakland. North of the Bay Bridge is Treasure Island. Alcatraz Island appears as a small dot northwest of Treasure Island. This image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on orbit 56. The image is centered at 37 degrees north latitude, 122degrees west longitude. This single-frequency SIR-C image was obtained by the L-band (24 cm) radar channel, horizontally transmitted and received. Portions of the Pacific Ocean visible in this image appear very dark as do other smooth surfaces such as airport runways. Suburban areas, with the low-density housing and tree-lined streets that are typical of San Francisco, appear as lighter gray. Areas with high-rise buildings, such as those seen in the downtown areas, appear in very bright white, showing a higher density of housing and streets which run parallel to the radar flight track. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: the L-band (24 cm), C-band (6 cm) and X-band (3cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes

  10. Space Radar Image of Los Angeles, California

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a radar image of Los Angeles, California, taken on October 2, 1994. Visible in the image are Long Beach Harbor at the bottom right (south corner of the image), Los Angeles International Airport at the bottom center, with Santa Monica just to the left of it and the Hollywood Hills to the left of Santa Monica. Also visible in the image are the freeway systems of Los Angeles, which appear as dark lines. The San Gabriel Mountains (center top) and the communities of San Fernando Valley, Simi Valley and Palmdale can be seen on the left-hand side. This image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 24th orbit. The image is centered at 34 degrees north latitude, 118 degrees west longitude. The area shown is approximately 100 kilometers by 52 kilometers (62 miles by 32 miles). This single-frequency SIR-C image was obtained by the L-band (24 cm) radar channel, horizontally transmitted and received. Portions of the Pacific Ocean visible in this image appear very dark as do freeways and other flat surfaces such as the airport runways. Mountains in the image are dark grey, with brighter patches on the mountain slopes, which face in the direction of the radar illumination (from the top of the image). Suburban areas, with the low-density housing and tree-lined streets that are typical of Los Angeles, appear as lighter grey. Areas with high-rise buildings, such as downtown Los Angeles, appear in very bright white, showing a higher density of housing and streets which run parallel to the radar flight track. Scientists hope to use radar image data from SIR-C/X-SAR to map fire scars in areas prone to brush fires, such as Los Angeles. In this image, the Altadena fire area is visible in the top center of the image as a patch of mountainous terrain which is slightly darker than the nearby mountains. Using all the radar frequency and polarization images provided by SIR

  11. Radar Imaging for Urban Sensing

    DTIC Science & Technology

    2010-04-01

    targets behind walls," Proceedings of the EUSIPCO 2009, Glasgow, Scotland , August 2009. [13] F. Ahmad and M. G. Amin, "Waveform design for...and Navigation, Vol. 148, No. 3, pp. 130-138, June 2001. [22] E. J. Roth well, W. Sun, "Time domain decon volution of transient radar data," IEEE Trans

  12. Space Radar Image of Ventura County, California

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This radar image of Ventura County, California, shows the Santa Clara River valley and the surrounding mountains. The river valley is the linear feature that extends from the lower right to the upper left (east to west), where it empties into the Pacific Ocean (dark patches in upper and lower left). The cities of Ventura and Oxnard are seen along the left side of the image. Simi Valley is located in the lower center of the image, between the Santa Monica Mountains (purple area in lower left) and the Santa Susanna Mountains to the north. This area of California is known for its fruit; strawberry fields are shown in red and purple rectangular areas on the coastal plain, and citrus groves are the yellow green areas adjacent to the river. This image is centered at 34.33 degrees north latitude, 119 degrees west longitude. The area shown is approximately 53 kilometers by 35 kilometers (33 miles by 22 miles). Colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted, horizontally received; green is L-band, horizontally transmitted, vertically received; blue is C-band, horizontally transmitted, vertically received. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture (SIR-C/X-SAR) imaging radar when it flew aboard the space shuttle Endeavour on October 6, 1994.

  13. Space Radar Image of Boston, Massachusetts

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This radar image of the area surrounding Boston, Mass., shows how a spaceborne radar system distinguishes between densely populated urban areas and nearby areas that are relatively unsettled. The bright white area at the right center of the image is downtown Boston. The wide river below and to the left of the city is the Charles River in Boston's Back Bay neighborhood. The dark green patch to the right of the Back Bay is Boston Common. A bridge across the north end of Back Bay connects the cities of Boston and Cambridge. The light green areas that dominate most of the image are the suburban communities surrounding Boston. The many ponds that dot the region appear as dark irregular spots. Many densely populated urban areas show up as red in the image due to the alignment of streets and buildings to the incoming radar beam. North is toward the upper left. The image was acquired on October 9, 1994, by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) as it flew aboard the space shuttle Endeavour. This area is centered at 42.4 degrees north latitude, 71.2 degrees west longitude. The area shown is approximately 37 km by 18 km (23 miles by 11 miles). Colors are assigned to different radar frequencies and polarizations as follows: red is L-band horizontally transmitted, horizontally received; green is L-band horizontally transmitted, vertically received; blue is C-band horizontally transmitted, vertically received. SIR-C/X-SAR, a cooperative mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  14. Space Radar Image of Hampton Roads, Virginia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This radar image shows the Hampton Roads, Virginia region, where the James River (upper left center) flows into the Chesapeake Bay. The city of Norfolk is the bright area on the peninsula in the lower center. Norfolk is home to a large naval base, part of which can be seen as the bright white port facilities near the center of the image. The cities of Hampton and Newport News occupy the peninsula in the upper right of the image. The dark blue areas on this peninsula are the runways of Langley Air Force Base, which also houses NASA's Langley Research Center. Forested areas, including suburbs, appear as green on the image. Cities appear as green, white and orange. The purple areas along the shorelines are wetlands; blue areas are cleared for agricultural use. Faint ship wakes can be seen in the water behind ships entering and leaving Hampton Roads. Scientists are using radar images like this one to study delicate coastal environments and the effects of urbanization and other human activities on the ecosystem and landscape. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture (SIR-C/X-SAR) imaging radar when it flew aboard the space shuttle Endeavour on October 5, 1994. The image is centered at 36.9 degrees north latitude, 76.4 degrees west longitude. North is towards the upper right. The area shown is 37 kilometers by 29 kilometers (23 miles by 18 miles). Colors are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, horizontally received; green is L-band horizontally transmitted, vertically received; blue is C-band horizontally transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's ongoing Mission to Planet Earth program.

  15. Space Radar Image of Athens, Greece

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This space radar image of Athens, Greece, shows the sprawling, modern development of this ancient capital city. Densely populated urban areas appear in shades of pink and light green. The Acropolis the dark green triangular patch in the center of the image. Archaeological discoveries indicate Athens has been continuously occupied for at least the last 5,000 years. Numerous ships, shown as bright dots, are seen in the harbor areas in the upper left part of the image. The port city of Piraeus is at the left center. This image is 45 kilometers by 45 kilometers (28 miles by 28 miles) and is centered at 37.9 degrees north latitude, 23.7 degrees east longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations are as follows: red is L-band, horizontally transmitted and received; green is L-band, horizontally transmitted and vertically received; and blue is C-band, horizontally transmitted and received. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on October 2, 1994 onboard the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  16. Space Radar Image of Weddell Sea

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Two radar images are shown in this composite to compare the size of a standard spaceborne radar image (small inset) to the image that is created when the radar instrument is used in the ScanSAR mode (large image). The predominant image shows two large ocean circulation features, called eddies, at the northernmost edge of the sea ice pack in the Weddell Sea, off Antarctica. The eddy processes in this region play an important role in the circulation of the global ocean and the transportation of heat toward the pole. The large image is the first wide-swath, multi-frequency, multi-polarization radar image ever processed. To date, no other spaceborne radar sensors have obtained swaths exceeding 100 kilometers (62 miles) in width. This developmental image was produced at NASA's Jet Propulsion Laboratory by the Alaska SAR Facility's ScanSAR processor system, using radar data obtained on October 5, 1994, during the second flight of the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour. The image is oriented approximately east-west, with a center location of around 56.6 degrees south latitude and 6.5 degrees west longitude. Image dimensions are 240 km by 350 km (149 miles by 218 miles). The smaller image inset (upper right edge) was obtained by SIR-C/X-SAR on October 6, 1994, and covers a portion of the same ice features that are shown in the large image. The inset image dimensions are 18 km by 50 km (11 miles by 31 miles). The ocean eddies have a clockwise (or cyclonic) rotation and are roughly 40 km to 60 km (25 miles to 37 miles) in diameter. The dark areas are new ice and the lighter green areas are small sea-ice floes that are swept along by surface currents; both of these areas are shown within the eddies and to the south of the eddies. First year seasonal ice, typically 0.5 meter to 0.8 meter (1.5 feet to 2.5 feet) thick, is shown in the darker green area in the lower right corner. The open ocean to the north

  17. Space radar image of New Orleans, Louisiana

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This image of the area surrounding the city of New Orleans, Louisiana in the southeastern United States demonstrates the ability of multi-frequency imaging radar to distinguish different types of land cover. The dark area in the center is Lake Pontchartrain. The thin line running across the lake is a causeway connecting New Orleans to the city of Mandeville. Lake Borgne is the dark area in the lower right of the image. The Mississippi River appears as a dark, wavy line in the lower left. The white dots on the Mississippi are ships. The French Quarter is the brownish square near the left center of the image. Lakefront Airport, a field used mostly for general aviation, is the bright spot near the center, jutting out into Lake Pontchartrain. The image was acquired by the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) during orbit 39 of space shuttle Endeavour on October 2, 1994. The area is located at 30.10 degrees north latitude and 89.1 degrees west longitude. The area shown is approximately 100 kilometers (60 miles) by 50 kilometers (30 miles). The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the C-band (horizontally transmitted and received); blue represents the L-band (vertically transmitted and received). The green areas are primarily vegetation consisting of swamp land and swamp forest (bayou) growing on sandy soil, while the pink areas are associated with reflections from buildings in urban and suburban areas. Different tones and colors in the vegetation areas will be studied by scientists to see how effective imaging radar data is in discriminating between different types of wetlands. Accurate maps of coastal wetland areas are important to ecologists studying wild fowl and the coastal environment.

  18. Space Radar Image of Teide Volcano

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This radar image shows the Teide volcano on the island of Tenerife in the Canary Islands. The Canary Islands, part of Spain, are located in the eastern Atlantic Ocean off the coast of Morocco. Teide has erupted only once in the 20th Century, in 1909, but is considered a potentially threatening volcano due to its proximity to the city of Santa Cruz de Tenerife, shown in this image as the purple and white area on the lower right edge of the island. The summit crater of Teide, clearly visible in the left center of the image, contains lava flows of various ages and roughnesses that appear in shades of green and brown. Different vegetation zones, both natural and agricultural, are detected by the radar as areas of purple, green and yellow on the volcano's flanks. Scientists are using images such as this to understand the evolution of the structure of Teide, especially the formation of the summit caldera and the potential for collapse of the flanks. The volcano is one of 15 identified by scientists as potentially hazardous to local populations, as part of the international The image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on October 11, 1994. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. The image is centered at 28.3 degrees North latitude and 16.6 degrees West longitude. North is toward the upper right. The area shown measures 90 kilometers by 54.5 kilometers (55.8 miles by 33.8 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, horizontally received; green is L-band horizontally transmitted, vertically received; blue is C-band horizontally transmitted, vertically received.

  19. Space Radar Image of Honolulu, Oahu, Hawaii

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image shows the city of Honolulu, Hawaii and adjacent areas on the island of Oahu. Honolulu lies on the south shore of the island, along the bottom of this image. Diamond Head, an extinct volcanic crater, is seen in the lower right. The bright white strip left of Diamond Head is the Waikiki Beach area. Further west are the downtown area and harbor. Runways of the airport can be seen in the lower left. The Koolau mountain range runs through the center of the image. The steep cliffs on the north side of the range are thought to be remnants of massive landslides that ripped apart the volcanic mountains that built the island thousands of years ago. On the north shore of the island are the Mokapu peninsula and Kaneohe Bay. Densely vegetated areas appear green in this radar image, while urban areas generally appear orange, red or white. Images such as this can be used by land use planners to monitor urban development and its effect on the tropical environment. The image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttleEndeavour on October 6, 1994.The image is 20.6 kilometers by 31.0kilometers (12.8 miles by 19.2 miles) and is centered at 21.4degrees North latitude, 157.8 degrees West longitude. North is toward the upper left. The colors are assigned to different radarfrequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted and received; green is L-band, horizontally transmitted, vertically received; and blue is C-band, horizontally transmitted, vertically received. SIR-C/X-SAR,a joint mission of the German, Italian, and United States space agencies, is part of NASA's Mission to Planet Earth.

  20. Wetland mapping with imaging radar

    NASA Technical Reports Server (NTRS)

    Waite, W. P.; Macdonald, H. C.; Kaupp, V. H.; Demarcke, J. S.

    1981-01-01

    An analysis of Seasat radar imagery is presented to identify the radar signature of vegetation-covered water surfaces. Imagery taken on Aug. 21, 1978 displayed anomalously high returns over swamp lands near Lafayette, LA. Landsat scans of the area two days later revealed uniform vegetation cover in the area, and ground examination found the area to be filled with cypress trees in swamps. Similar results were obtained during an overflight above a region of southeast Arkansas. Mechanisms producing the high degree of reflectance are explored, and the possibility that the strong return is due to an interaction of the vegetation cover and the specular water surface underneath is mentioned. Further studies to identify the exact mechanisms producing the anomalous returns are recommended, as well as optimization of the viewing angle for general classes of vegetation density.

  1. Space Radar Image of Mt. Etna, Italy

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The summit of the Mount Etna volcano on the island of Sicily, Italy, one of the most active volcanoes in the world, is shown near the center of this radar image. Lava flows of different ages and surface roughness appear in shades of purple, green, yellow and pink surrounding the four small craters at the summit. Etna is one of the best-studied volcanoes in the world and scientists are using this radar image to identify and distinguish a variety of volcanic features. Etna has erupted hundreds of times in recorded history, with the most recent significant eruption in 1991-1993. Scientists are studying Etna as part of the international 'Decade Volcanoes' project, because of its high level of activity and potential threat to local populations. This image was acquired on October 11, 1994 by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. The image is centered at 37.8 degrees North latitude and 15.1 degrees East longitude and covers an area of 51.2 kilometers by 22.6 kilometers (31.7 miles by 14.0 miles).

  2. Space Radar Image of La Paz, Bolivia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an image of the Bolivian capital city of La Paz that was created using three radar frequencies. La Paz sits at the edge of the Altiplano, the high inland plateau between the Cordillera Occidental and Cordillera Oriental belts of the Andes Mountains in South America. Part of the Cordillera Oriental mountains are seen on the right side (northeast) of this image. The bright areas at the top of the mountains are most likely the result of year-round snow cover. Glacier-carved valleys drain the mountain areas. The dark lines left of center are Kennedy Airport near the northwestern part of the city. The image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on April 18, 1994. The image is centered at 16.25 degrees south latitude, 68.1 degrees west longitude. The area shown is approximately 35 kilometers by 16 kilometers (22 miles by 10 miles). North is toward the upper right. Colors are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, horizontally received; green is C-band horizontally transmitted, vertically received; and blue is X-band vertically transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's program called Mission to Planet Earth.

  3. Shuttle imaging radar-C science plan

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The Shuttle Imaging Radar-C (SIR-C) mission will yield new and advanced scientific studies of the Earth. SIR-C will be the first instrument to simultaneously acquire images at L-band and C-band with HH, VV, HV, or VH polarizations, as well as images of the phase difference between HH and VV polarizations. These data will be digitally encoded and recorded using onboard high-density digital tape recorders and will later be digitally processed into images using the JPL Advanced Digital SAR Processor. SIR-C geologic studies include cold-region geomorphology, fluvial geomorphology, rock weathering and erosional processes, tectonics and geologic boundaries, geobotany, and radar stereogrammetry. Hydrology investigations cover arid, humid, wetland, snow-covered, and high-latitude regions. Additionally, SIR-C will provide the data to identify and map vegetation types, interpret landscape patterns and processes, assess the biophysical properties of plant canopies, and determine the degree of radar penetration of plant canopies. In oceanography, SIR-C will provide the information necessary to: forecast ocean directional wave spectra; better understand internal wave-current interactions; study the relationship of ocean-bottom features to surface expressions and the correlation of wind signatures to radar backscatter; and detect current-system boundaries, oceanic fronts, and mesoscale eddies. And, as the first spaceborne SAR with multi-frequency, multipolarization imaging capabilities, whole new areas of glaciology will be opened for study when SIR-C is flown in a polar orbit.

  4. Space Radar Image of Manaus, Brazil

    NASA Technical Reports Server (NTRS)

    1999-01-01

    These two images were created using data from the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR). On the left is a false-color image of Manaus, Brazil acquired April 12, 1994, onboard space shuttle Endeavour. In the center of this image is the Solimoes River just west of Manaus before it combines with the Rio Negro to form the Amazon River. The scene is around 8 by 8 kilometers (5 by 5 miles) with north toward the top. The radar image was produced in L-band where red areas correspond to high backscatter at HH polarization, while green areas exhibit high backscatter at HV polarization. Blue areas show low backscatter at VV polarization. The image on the right is a classification map showing the extent of flooding beneath the forest canopy. The classification map was developed by SIR-C/X-SAR science team members at the University of California,Santa Barbara. The map uses the L-HH, L-HV, and L-VV images to classify the radar image into six categories: Red flooded forest Green unflooded tropical rain forest Blue open water, Amazon river Yellow unflooded fields, some floating grasses Gray flooded shrubs Black floating and flooded grasses Data like these help scientists evaluate flood damage on a global scale. Floods are highly episodic and much of the area inundated is often tree-covered. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those

  5. Space Radar Image of Oil Slicks

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a radar image of an offshore drilling field about 150 km (93 miles) west of Bombay, India, in the Arabian Sea. The dark streaks are extensive oil slicks surrounding many of the drilling platforms, which appear as bright white spots. Radar images are useful for detecting and measuring the extent of oil seepages on the ocean surface, from both natural and industrial sources. The long, thin streaks extending from many of the platforms are spreading across the sea surface, pushed by local winds. The larger dark patches are dispersed slicks that were likely discharged earlier than the longer streaks, when the winds were probably from a different direction. The dispersed oil will eventually spread out over the more dense water and become a layer which is a single molecule thick. Many forms of oil, both from biological and from petroleum sources, smooth out the ocean surface, causing the area to appear dark in radar images. There are also two forms of ocean waves shown in this image. The dominant group of large waves (upper center) are called internal waves. These waves are formed below the ocean surface at the boundary between layers of warm and cold water and they appear in the radar image because of the way they change the ocean surface. Ocean swells, which are waves generated by winds, are shown throughout the image but are most distinct in the blue area adjacent to the internal waves. Identification of waves provide oceanographers with information about the smaller scale dynamic processes of the ocean. This image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on October 9, 1994. The colors are assigned to different frequencies and polarizations of the radar as follows: Red is L-band vertically transmitted, vertically received; green is the average of L-band vertically transmitted, vertically received and C-band vertically transmitted, vertically received; blue is C

  6. Space Radar Image of Tuva, Central Asia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image shows part of the remote central Asian region of Tuva, an autonomous republic of the Russian Federation. Tuva is a mostly mountainous region that lies between western Mongolia and southern Siberia. This image shows the area just south of the republic's capital of Kyzyl. Most of the red, pink and blue areas in the image are agricultural fields of a large collective farming complex that was developed during the era of the Soviet Union. Traditional agricultural activity in the region, still active in remote areas, revolves around practices of nomadic livestock herding. White areas on the image are north-facing hillsides, which develop denser forests than south-facing slopes. The river in the upper right is one of the two major branches of the Yenesey River. Tuva has received some notoriety in recent years due to the intense interest of the celebrated Caltech physicist Dr. Richard Feynman, chronicled in the book 'Tuva or Bust' by Ralph Leighton. The image was acquired by Spaceborne Imaging Radar-C/X-Band SyntheticAperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour onOctober 1, 1994. The image is 56 kilometers by 74 kilometers (35 miles by 46 miles) and is centered at 51.5 degrees north latitude, 95.1 degrees east longitude. North is toward the upper right. The colors are assigned to different radar fequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted andreceived; green is L-band, horizontally transmitted and vertically received; and blue is C-band, horizontally transmitted and verticallyreceived. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to PlanetEarth program.

  7. Space Radar Image of Pishan, China

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This radar image is centered near the small town of Pishan in northwest China, about 280 km (174 miles) southeast of the city of Kashgar along the ancient Silk Route in the Taklamakan desert of the Xinjiang Province. Geologists are using this radar image as a map to study past climate changes and tectonics of the area. The irregular lavender branching patterns in the center of the image are the remains of ancient alluvial fans, gravel deposits that have accumulated at the base of the mountains during times of wetter climate. The subtle striped pattern cutting across the ancient fans are caused by thrusting of the Kun Lun Mountains north. This motion is caused by the continuing plate-tectonic collision of India with Asia. Modern fans show up as large lavender triangles above the ancient fan deposits. Yellow areas on the modern fans are vegetated oases. The gridded pattern results from the alignment of poplar trees that have been planted as wind breaks. The reservoir at the top of the image is part of a sophisticated irrigation system that supplies water to the oases. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour in April 1994. This image is centered at 37.4 degrees north latitude, 78.3 degrees east longitude and shows an area approximately 50 km by 100 km (31 miles by 62 miles). The colors are assigned to different frequencies and polarizations of the radar as follows: Red is L-band horizontally transmitted, horizontally received; green is L-band horizontally transmitted, vertically received; and blue is C-band horizontally transmitted and vertically received. SIR-C/X-SAR, a joint mission of the German, Italian, and the United States space agencies, is part of NASA's Mission to Planet Earth.

  8. Radar Image, Color as Height , Salalah, Oman

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This radar image includes the city of Salalah, the second largest city in Oman. It illustrates how topography determines local climate and, in turn, where people live. This area on the southern coast of the Arabian Peninsula is characterized by a narrow coastal plain (bottom) facing southward into the Arabian Sea, backed by the steep escarpment of the Qara Mountains. The backslope of the Qara Mountains slopes gently into the vast desert of the Empty Quarter (at top). This area is subject to strong monsoonal storms from the Arabian Sea during the summer, when the mountains are enveloped in a sort of perpetual fog. The moisture from the monsoon enables agriculture on the Salalah plain, and also provides moisture for Frankincense trees growing on the desert (north) side of the mountains. In ancient times, incense derived from the sap of the Frankincense tree was the basis for an extremely lucrative trade. Radar and topographic data are used by historians and archaeologists to discover ancient trade routes and other significant ruins.

    This image combines two types of data from the Shuttle Radar Topography Mission. The image brightness corresponds to the strength of the radar signal reflected from the ground, while colors show the elevation as measured by SRTM. Colors range from green at the lowest elevations to brown at the highest elevations. This image contains about 1070 meters (3500 feet) of total relief. White speckles on the face of some of the mountains are holes in the data caused by steep terrain. These will be filled using coverage from an intersecting pass.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter

  9. Ultra wideband ground penetrating radar imaging of heterogeneous solids

    DOEpatents

    Warhus, John P.; Mast, Jeffrey E.

    1998-01-01

    A non-invasive imaging system for analyzing engineered structures comprises pairs of ultra wideband radar transmitters and receivers in a linear array that are connected to a timing mechanism that allows a radar echo sample to be taken at a variety of delay times for each radar pulse transmission. The radar transmitters and receivers are coupled to a position determining system that provides the x,y position on a surface for each group of samples measured for a volume from the surface. The radar transmitter and receivers are moved about the surface, e.g., attached to the bumper of a truck, to collect such groups of measurements from a variety of x,y positions. Return signal amplitudes represent the relative reflectivity of objects within the volume and the delay in receiving each signal echo represents the depth at which the object lays in the volume and the propagation speeds of the intervening material layers. Successively deeper z-planes are backward propagated from one layer to the next with an adjustment for variations in the expected propagation velocities of the material layers that lie between adjacent z-planes.

  10. Ultra wideband ground penetrating radar imaging of heterogeneous solids

    DOEpatents

    Warhus, J.P.; Mast, J.E.

    1998-11-10

    A non-invasive imaging system for analyzing engineered structures comprises pairs of ultra wideband radar transmitters and receivers in a linear array that are connected to a timing mechanism that allows a radar echo sample to be taken at a variety of delay times for each radar pulse transmission. The radar transmitters and receivers are coupled to a position determining system that provides the x,y position on a surface for each group of samples measured for a volume from the surface. The radar transmitter and receivers are moved about the surface, e.g., attached to the bumper of a truck, to collect such groups of measurements from a variety of x,y positions. Return signal amplitudes represent the relative reflectivity of objects within the volume and the delay in receiving each signal echo represents the depth at which the object lays in the volume and the propagation speeds of the intervening material layers. Successively deeper z-planes are backward propagated from one layer to the next with an adjustment for variations in the expected propagation velocities of the material layers that lie between adjacent z-planes. 11 figs.

  11. Super-resolution techniques for velocity estimation using UWB random noise radar signals

    NASA Astrophysics Data System (ADS)

    Dawood, Muhammad; Quraishi, Nafish; Alejos, Ana V.

    2011-06-01

    The Doppler spread pertaining to the ultrawideband (UWB) radar signals from moving target is directly proportional to the bandwidth of the transmitted signal and the target velocity. Using typical FFT-based methods, the estimation of true velocities pertaining to two targets moving with relatively close velocities within a radar range bin is problematic. In this paper, we extend the Multiple Signal Classification (MUSIC) algorithm to resolve targets moving velocities closer to each other within a given range bin for UWB random noise radar waveforms. Simulated and experimental results are compared for various target velocities using both narrowband (200MHz) and wideband (1GHz) noise radar signals, clearly establishing the unbiased and unambiguous velocity estimations using the MUSIC algorithm.

  12. Radar image San Francisco Bay Area, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The San Francisco Bay Area in California and its surroundings are shown in this radar image from the Shuttle Radar Topography Mission (SRTM). On this image, smooth areas, such as the bay, lakes, roads and airport runways appear dark, while areas with buildings and trees appear bright. Downtown San Francisco is at the center and the city of Oakland is at the right across the San Francisco Bay. Some city areas, such as the South of Market district in San Francisco, appear bright due to the alignment of streets and buildings with respect to the incoming radar beam. Three of the bridges spanning the Bay are seen in this image. The Bay Bridge is in the center and extends from the city of San Francisco to Yerba Buena and Treasure Islands, and from there to Oakland. The Golden Gate Bridge is to the left and extends from San Francisco to Sausalito. The Richmond-San Rafael Bridge is in the upper right and extends from San Rafael to Richmond. Angel Island is the large island east of the Golden Gate Bridge, and lies north of the much smaller Alcatraz Island. The Alameda Naval Air Station is seen just below the Bay Bridge at the center of the image. Two major faults bounding the San Francisco-Oakland urban areas are visible on this image. The San Andreas fault, on the San Francisco peninsula, is seen on the left side of the image. The fault trace is the straight feature filled with linear reservoirs, which appear dark. The Hayward fault is the straight feature on the right side of the image between the urban areas and the hillier terrain to the east.

    This radar image was acquired by just one of SRTM's two antennas and, consequently, does not show topographic data, but only the strength of the radar signal reflected from the ground. This signal, known as radar backscatter, provides insight into the nature of the surface, including its roughness, vegetation cover and urbanization. The overall faint striping pattern in the images is a data processing artifact due to the

  13. Space Radar Image of Florence, Italy

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This radar image shows land use patterns in and around the city of Florence, Italy, shown here in the center of the image. Florence is situated on a plain in the Chianti Hill region of Central Italy. The Arno River flows through town and is visible as the dark line running from the upper right to the bottom center of the image. The city is home to some of the world's most famous art museums. The bridges seen crossing the Arno, shown as faint red lines in the upper right portion of the image, were all sacked during World War II with the exception of the Ponte Vecchio, which remains as Florence's only covered bridge. The large, black V-shaped feature near the center of the image is the Florence Railroad Station. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the Space Shuttle Endeavour on April 14, 1994. SIR-C/X-SAR, a joint mission of the German, Italian, and United States space agencies, is part of NASA's Mission to Planet Earth. This image is centered at 43.7 degrees north latitude and 11.15 degrees east longitude with North toward the upper left of the image. The area shown measures 20 kilometers by 17 kilometers (12.4 miles by 10.6 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, horizontally received; green is L-band horizontally transmitted, vertically received; blue is C-band horizontally transmitted, vertically received.

  14. Mississippi Delta, Radar Image with Colored Height

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for the animation

    About the animation: This simulated view of the potential effects of storm surge flooding on Lake Pontchartrain and the New Orleans area was generated with data from the Shuttle Radar Topography Mission. Although it is protected by levees and sea walls against storm surges of 18 to 20 feet, much of the city is below sea level, and flooding due to storm surges caused by major hurricanes is a concern. The animation shows regions that, if unprotected, would be inundated with water. The animation depicts flooding in one-meter increments.

    About the image: The geography of the New Orleans and Mississippi delta region is well shown in this radar image from the Shuttle Radar Topography Mission. In this image, bright areas show regions of high radar reflectivity, such as from urban areas, and elevations have been coded in color using height data also from the mission. Dark green colors indicate low elevations, rising through yellow and tan, to white at the highest elevations.

    New Orleans is situated along the southern shore of Lake Pontchartrain, the large, roughly circular lake near the center of the image. The line spanning the lake is the Lake Pontchartrain Causeway, the world's longest over water highway bridge. Major portions of the city of New Orleans are below sea level, and although it is protected by levees and sea walls, flooding during storm surges associated with major hurricanes is a significant concern.

    Data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on the Space Shuttle Endeavour in 1994. The Shuttle Radar Topography Mission was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data

  15. Space Radar Image of County Kerry, Ireland

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The Iveragh Peninsula, one of the four peninsulas in southwestern Ireland, is shown in this spaceborne radar image. The lakes of Killarney National Park are the green patches on the left side of the image. The mountains to the right of the lakes include the highest peaks (1,036 meters or 3,400 feet) in Ireland. The patchwork patterns between the mountains are areas of farming and grazing. The delicate patterns in the water are caused by refraction of ocean waves around the peninsula edges and islands, including Skellig Rocks at the right edge of the image. The Skelligs are home to a 15th century monastery and flocks of puffins. The region is part of County Kerry and includes a road called the 'Ring of Kerry' that is one of the most famous tourist routes in Ireland. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the Space Shuttle Endeavour on April 12, 1994. The image is 82 kilometers by 42 kilometers (51 miles by 26 miles) and is centered at 52.0 degrees north latitude, 9.9 degrees west longitude. North is toward the lower left. The colors are assigned to different radar frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted and received; green is L-band, vertically transmitted and received; and blue is C-band, vertically transmitted and received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  16. Space Radar Image of Reunion Island

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This radar image shows the volcanic island of Reunion, about 700 km (434 miles) east of Madagascar in the southwest Indian Ocean. The southern half of the island is dominated by the active volcano, Piton de la Fournaise. This is one of the world's most active volcanoes, with more than 100 eruptions in the last 300 years. The most recent activity occurred in the vicinity of Dolomieu Crater, shown in the lower center of the image within a horseshoe-shaped collapse zone. Recent lava flows appear in shades of red, purple and orange. Light green areas are heavily vegetated forest, while much of the purple area near the coast is farmland. The radar illumination is from the left side of the image and dramatically emphasizes the precipitous cliffs at the edges of the central canyons of the island. These canyons are remnants from the collapse of formerly active parts of the volcanoes that built the island. This image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on October 5, 1994. The image is centered at 21.2 degrees south latitude, 55.6 degrees east longitude. The area shown is approximately 50 km by 80 km (31 miles by 50 miles). North is toward the upper right. Colors are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, vertically received; green is L-band horizontally transmitted, vertically received; and blue is C-band horizontally transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth.

  17. Bibliography of geologic studies using imaging radar

    NASA Technical Reports Server (NTRS)

    Bryan, M. L.

    1979-01-01

    Articles concerning imaging studies on the geomorphology, mineralogy, and topology of various landforms are reported. One hundred and ninety citations are listed and an index by National Technical Information service citation number is included. Several illustrations of L-band radar imagery are presented.

  18. Radar images of asteroid 1989 PB

    NASA Astrophysics Data System (ADS)

    Ostro, S. J.; Chandler, J. F.; Hine, A. A.; Rosema, K. D.; Shapiro, I. I.; Yeomans, D. K.

    1990-06-01

    Radar observations of the near-earth asteroid 1989 PB, made shortly after its optical discovery, yield a sequence of delay-Doppler images that reveal it to consist of two distinct lobes that appear to be in contact. It seems likely that the two lobes once were separate and that they collided to produce the current 'contact-binary' configuration.

  19. Phase Calibration Of Polarimetric Radar Images

    NASA Technical Reports Server (NTRS)

    Freeman, Anthony; Sheen, Dan R.; Kasischke, Erik S.

    1992-01-01

    Report addresses problem of calibration of differences between phases (relative to transmitted signals) of signals received in two polarization channels of polarimetric imaging radar system. Causes of various types of errors discussed. Calibration necessary to deduce information about target area - type of terrain, presence of vegetation, and land/water boundaries.

  20. Through-Wall Imaging Radar

    DTIC Science & Technology

    2012-01-01

    receiver dynamic range to be applied to the target scene behind the wall. A time-division multiplexed ( TDM ), multiple-input, multiple-output (MIMO...by the data-acquisition computer. The TDM MIMO radar system sequences through each of the 44 bistatic combinations, acquiring one range profile at...96 5. 75 5. 75 2 FiGurE 5. In this cartoon of the time-division multiplexed ( TDM ), multiple-input, multiple-output (MIMO) array lay- out [compare to

  1. Space Radar Image of San Francisco, California

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This image of San Francisco, California shows how the radar distinguishes between densely populated urban areas and nearby areas that are relatively unsettled. Downtown San Francisco is at the center and the city of Oakland is at the right across the San Francisco Bay. Some city areas, such as the South of Market, called the SOMA district in San Francisco, appear bright red due to the alignment of streets and buildings to the incoming radar beam. Various bridges in the area are also visible including the Golden Gate Bridge (left center) at the opening of San Francisco Bay, the Bay Bridge (right center) connecting San Francisco and Oakland, and the San Mateo Bridge (bottom center). All the dark areas on the image are relatively smooth water: the Pacific Ocean to the left, San Francisco Bay in the center, and various reservoirs. Two major faults bounding the San Francisco-Oakland urban areas are visible on this image. The San Andreas fault, on the San Francisco peninsula, is seen in the lower left of the image. The fault trace is the straight feature filled with linear reservoirs which appear dark. The Hayward fault is the straight feature on the right side of the image between the urban areas and the hillier terrain to the east. The image is about 42 kilometers by 58 kilometers (26 miles by 36 miles) with north toward the upper right. This area is centered at 37.83 degrees north latitude, 122.38 degrees east longitude. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture (SIR-C/X-SAR) imaging radar when it flew aboard the space shuttle Endeavour on October 3, 1994. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth.

  2. Space radar image of Mauna Loa, Hawaii

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This image of the Mauna Loa volcano on the Big Island of Hawaii shows the capability of imaging radar to map lava flows and other volcanic structures. Mauna Loa has erupted more than 35 times since the island was first visited by westerners in the early 1800s. The large summit crater, called Mokuaweoweo Caldera, is clearly visible near the center of the image. Leading away from the caldera (towards top right and lower center) are the two main rift zones shown here in orange. Rift zones are areas of weakness within the upper part of the volcano that are often ripped open as new magma (molten rock) approaches the surface at the start of an eruption. The most recent eruption of Mauna Loa was in March and April 1984, when segments of the northeast rift zones were active. If the height of the volcano was measured from its base on the ocean floor instead of from sea level, Mauna Loa would be the tallest mountain on Earth. Its peak (center of the image) rises more than 8 kilometers (5 miles) above the ocean floor. The South Kona District, known for cultivation of macadamia nuts and coffee, can be seen in the lower left as white and blue areas along the coast. North is toward the upper left. The area shown is 41.5 by 75 kilometers (25.7 by 46.5 miles), centered at 19.5 degrees north latitude and 155.6 degrees west longitude. The image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/ X-SAR) aboard the space shuttle Endeavour on its 36th orbit on October 2, 1994. The radar illumination is from the left of the image. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted, vertically received); blue represents the C-band (horizontally transmitted, vertically received). The resulting color combinations in this radar image are caused by differences in surface roughness of the lava flows. Smoother flows

  3. Radar imaging of shallow water bathymetry: A case study in the Yangtze Estuary

    NASA Astrophysics Data System (ADS)

    Yu, Peng; Johannessen, Johnny A.; Kudryavtsev, Vladimir; Zhong, Xiaojing; Zhou, Yunxuan

    2016-12-01

    This study focuses on 2-dimensional (2-D) radar imaging of bathymetric features in the shallow water of the Yangtze Estuary using synthetic aperture radar (SAR) observations and model simulations. A validated 2-D shallow water numerical model simulates the barotropic current velocity, and the simulated current fields together with the relevant parameters of radar observations are then invoked in the radar imaging model as the input. The results show that variations in the simulated image intensity are mainly dominated by distinct radar backscatter anomalies caused by wave-current interactions in the vicinity of rapidly changing underwater topographies. The comparison between the simulated and observed SAR images shows a reasonable agreement, demonstrating that our approach may be implemented to monitor changes in the shallow water bathymetry of the Yangtze Estuary in the future.

  4. Forest discrimination with multipolarization imaging radar

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    The use of radar polarization diversity for discriminating forest canopy variables on airborne synthetic-aperture radar (SAR) images is evaluated. SAR images were acquired at L-Band (24.6 cm) simultaneously in four linear polarization states (HH, HV, VH, and VV) in South Carolina on March 1, 1984. In order to relate the polarization signatures to biophysical properties, false-color composite images were compared to maps of forest stands in the timber compartment. In decreasing order, the most useful correlative forest data are stand basal area, forest age, site condition index, and forest management type. It is found that multipolarization images discriminate variation in tree density and difference in the amount of understory, but do not discriminate between evergreen and deciduous forest types.

  5. Space Radar Image of Sacramento, California

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a spaceborne radar image of the city of Sacramento, the capital of California. Urban areas appear pink and the surrounding agricultural areas are green and blue. The Sacramento River is the curving dark line running from the left side of the image (northwest) to the bottom right. The American River is the dark curving line in the center. Sacramento is built at the junction of these two rivers and the state Capitol building is in the bright pink-white area southeast of the junction. The straighter dark line (lower center) is the Sacramento River Deep Water Ship Channel which allows ship access from San Francisco. The black areas in the center are the runways of the Sacramento Executive airport. The city of Davis, California is seen as a pink area in lower left. This image was acquired by Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on October 2, 1994. The image is 27.0 kilometers by 38.4 kilometers (17 miles by 24 miles) and is centered at 38.6 degrees North latitude, 125.1 degrees West longitude. North is toward the upper left. The colors are assigned to different radar frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontally transmitted and received; and blue is C-band, horizontally transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian, and United States space agencies, is part of NASA's Mission to Planet Earth.

  6. Space Radar Image of Harvard Forest

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a radar image of the area surrounding the Harvard Forest in north-central Massachusetts that has been operated as a ecological research facility by Harvard University since 1907. At the center of the image is the Quabbin Reservoir, and the Connecticut River is at the lower left of the image. The Harvard Forest itself is just above the reservoir. Researchers are comparing the naturally occurring physical disturbances in the forest and the recent and projected chemical disturbances and their effects on the forest ecosystem. Agricultural land appears dark blue/purple, along with low shrub vegetation and some wetlands. Urban development is bright pink; the yellow to green tints are conifer-dominated vegetation with the pitch pine sand plain at the middle left edge of the image appearing very distinctive. The green tint may indicate pure pine plantation stands, and deciduous broadleaf trees appear gray/pink with perhaps wetter sites being pinker. This image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. The image is centered at 42.50 degrees North latitude and 72.33 degrees West longitude and covers an area of 53 kilometers 63 by kilometers (33 miles by 39 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted and horizontally received; green is L-band horizontally transmitted and vertically received; and blue is C-band horizontally transmitted and horizontally received.

  7. Phase calibration of polarimetric radar images

    NASA Technical Reports Server (NTRS)

    Sheen, Dan R.; Kasischke, Eric S.; Freeman, Anthony

    1989-01-01

    The problem of phase calibration between polarization channels of an imaging radar is studied. The causes of various types of phase errors due to the radar system architecture and system imperfections are examined. A simple model is introduced to explain the spatial variation in phase error as being due to a displacement between the phase centers of the vertical and horizontal antennas. It is also shown that channel leakage can cause a spatial variation in phase error. Phase calibration using both point and distributed ground targets is discussed and a method for calibrating phase using only distributed target is verified, subject to certain constraints. Experimental measurements using the NADC/ERIM P-3 synthetic-aperture radar (SAR) system and NASA/JPL DC-8 SAR, which operates at C-, L-, and P-bands, are presented. Both of these systems are multifrequency, polarimetric, airborne, SAR systems.

  8. Mercury radar imaging: evidence for polar ice.

    PubMed

    Slade, M A; Butler, B J; Muhleman, D O

    1992-10-23

    The first unambiguous full-disk radar mapping of Mercury at 3.5-centimeter wavelength, with the Goldstone 70-meter antenna transmitting and 26 antennas of the Very Large Array receiving, has provided evidence for the presence of polar ice. The radar experiments, conducted on 8 and 23 August 1991, were designed to image the half of Mercury not photographed by Mariner 10. The orbital geometry allowed viewing beyond the north pole of Mercury; a highly reflective region was clearly visible on the north pole during both experiments. This polar region has areas in which the circular polarization ratio (pt) was 1.0 to 1.4; values < approximately 0.1 are typical for terrestrial planets. Such high values of have hitherto been observed in radar observations only from icy regions of Mars and icy outer planet satellites.

  9. Space Radar Image of Kilauea, Hawaii

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Data acquired on April 13, 1994 and on October 4, 1994 from the X-band Synthetic Aperture Radar on board the space shuttle Endeavour were used to generate interferometric fringes, which were overlaid on the X-SAR image of Kilauea. The volcano is centered in this image at 19.58 degrees north latitude and 155.55 degrees west longitude. The image covers about 9 kilometers by 13 kilometers (5.6 miles by 8 miles). The X-band fringes correspond clearly to the expected topographic image. The yellow line indicates the area below which was used for the three-dimensional image using altitude lines. The yellow rectangular frame fences the area for the final topographic image. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.V.(DLR), the major partner in science, operations and data processing of X-SAR. The Instituto Ricerca Elettromagnetismo Componenti Elettronici (IRECE) at the University of Naples was a partner in interferometry analysis.

  10. Space Radar Image of Canberra, Australia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Australia's capital city, Canberra, is shown in the center of this spaceborne radar image. Images like this can help urban planners assess land use patterns. Heavily developed areas appear in bright patchwork patterns of orange, yellow and blue. Dense vegetation appears bright green, while cleared areas appear in dark blue or black. Located in southeastern Australia, the site of Canberra was selected as the capital in 1901 as a geographic compromise between Sydney and Melbourne. Design and construction of the city began in 1908 under the supervision of American architect Walter Burley-Griffin. Lake Burley-Griffin is located above and to the left of the center of the image. The bright pink area is the Parliament House. The city streets, lined with government buildings, radiate like spokes from the Parliament House. The bright purple cross in the lower left corner of the image is a reflection from one of the large dish-shaped radio antennas at the Tidbinbilla, Canberra Deep Space Network Communication Complex, operated jointly by NASA and the Australian Space Office. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on April 10, 1994, onboard the space shuttle Endeavour. The image is 28 kilometers by 25 kilometers (17 miles by 15 miles) and is centered at 35.35 degrees south latitude, 149.17 degrees east longitude. North is toward the upper left. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is L-band, horizontally transmitted and vertically received; and blue is C-band, horizontally transmitted and vertically received. SIR-C/X-SAR, a joint mission of the German, Italian, and United States space agencies, is part of NASA's Office of Mission to Planet Earth.

  11. Space Radar Image of Victoria, Canada

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This three-frequency spaceborne radar image shows the southern end of Vancouver Island on the west coast of Canada. The white area in the lower right is the city of Victoria, the capital of the province of British Columbia. The three radar frequencies help to distinguish different land use patterns. The bright pink areas are suburban regions, the brownish areas are forested regions, and blue areas are agricultural fields or forest clear-cuts. Founded in 1843 as a fur trading post, Victoria has grown to become one of western Canada's largest commercial centers. In the upper right is San Juan Island, in the state of Washington. The Canada/U.S. border runs through Haro Strait, on the right side of the image, between San Juan Island and Vancouver Island. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on October 6, 1994, onboard the space shuttle Endeavour. The area shown is 37 kilometers by 42 kilometers (23 miles by 26 miles) and is centered at 48.5 degrees north latitude, 123.3 degrees west longitude. North is toward the upper left. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band horizontally transmitted and received; green is C-band, vertically transmitted and received; and blue is X-band, vertically transmitted and received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  12. Space Radar Image of Raco Biomass Map

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This biomass map of the Raco, Michigan, area was produced from data acquired by the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard space shuttle Endeavour. Biomass is the amount of plant material on an area of Earth's surface. Radar can directly sense the quantity and organizational structure of the woody biomass in the forest. Science team members at the University of Michigan used the radar data to estimate the standing biomass for this Raco site in the Upper Peninsula of Michigan. Detailed surveys of 70 forest stands will be used to assess the accuracy of these techniques. The seasonal growth of terrestrial plants, and forests in particular, leads to the temporary storage of large amounts of carbon, which could directly affect changes in global climate. In order to accurately predict future global change, scientists need detailed information about current distribution of vegetation types and the amount of biomass present around the globe. Optical techniques to determine net biomass are frustrated by chronic cloud-cover. Imaging radar can penetrate through cloud-cover with negligible signal losses. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German

  13. Biometric identification using holographic radar imaging techniques

    NASA Astrophysics Data System (ADS)

    McMakin, Douglas L.; Sheen, David M.; Hall, Thomas E.; Kennedy, Mike O.; Foote, Harlen P.

    2007-04-01

    Pacific Northwest National Laboratory researchers have been at the forefront of developing innovative screening systems to enhance security and a novel imaging system to provide custom-fit clothing using holographic radar imaging techniques. First-of-a-kind cylindrical holographic imaging systems have been developed to screen people at security checkpoints for the detection of concealed, body worn, non-metallic threats such as plastic and liquid explosives, knifes and contraband. Another embodiment of this technology is capable of obtaining full sized body measurements in near real time without the person under surveillance removing their outer garments. Radar signals readily penetrate clothing and reflect off the water in skin. This full body measurement system is commercially available for best fitting ready to wear clothing, which was the first "biometric" application for this technology. One compelling feature of this technology for security biometric applications is that it can see effectively through disguises, appliances and body hair.

  14. Biometric Identification Using Holographic Radar Imaging Techniques

    SciTech Connect

    McMakin, Douglas L.; Sheen, David M.; Hall, Thomas E.; Kennedy, Mike O.; Foote, Harlan P.

    2007-04-01

    Pacific Northwest National Laboratory researchers have been at the forefront of developing innovative screening systems to enhance security and a novel imaging system to provide custom-fit clothing using holographic radar imaging techniques. First-of-a-kind cylindrical holographic imaging systems have been developed to screen people at security checkpoints for the detection of concealed, body worn, non-metallic threats such as plastic and liquid explosives, knifes and contraband. Another embodiment of this technology is capable of obtaining full sized body measurements in near real time without the person under surveillance removing their outer garments. Radar signals readily penetrate clothing and reflect off the water in skin. This full body measurement system is commercially available for best fitting ready to wear clothing, which was the first “biometric” application for this technology. One compelling feature of this technology for security biometric applications is that it can see effectively through disguises, appliances and body hair.

  15. Space Radar Image of Central Java, Indonesia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The summits of two large volcanoes in Central Java, Indonesia are shown in the center of this radar image. Lava flows of different ages and surface roughness appear in shades of green and yellow surrounding the summit of Mt. Merbabu (mid-center) and Mt. Merapi (lower center). Mt. Merapi erupted on November 28, 1994 about six weeks after this image was taken. The eruption killed more than 60 people and forced the evacuation of more than 6,000 others. Thousands of other residents were put on alert due to the possibility of volcanic debris mudflows, called lahars, that threatened nearby towns. Mt. Merapi is located approximately 40 kilometers (25 miles) north of Yogyakarta, the capital of Central Java. The older volcano at the top of the image is unnamed. Lake Rawapening is the dark blue feature in the upper right. The light blue area southeast of the lake is the city of Salatiga. Directly south of Salatiga and southeast of Mt. Merapi is the city of Boyolali. Scientists are studying Mt. Merapi as part of the international 'Decade Volcanoes' project, because of its recent activity and potential threat to local populations. The radar data are being used to identify and distinguish a variety of volcanic features. This image was acquired on October 10, 1994 by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. The image is centered at 7.5 degrees South latitude and 110.5 degrees East longitude and covers an area of 33 kilometers by 65 kilometers (20 miles by 40 miles).

  16. Space Radar Image of Sydney, Australia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image is dominated by the metropolitan area of Australia's largest city, Sydney. Sydney Harbour, with numerous coves and inlets, is seen in the upper center of the image, and the roughly circular Botany Bay is shown in the lower right. The downtown business district of Sydney appears as a bright white area just above the center of the image. The Sydney Harbour Bridge is a white line adjacent to the downtown district. The well-known Sydney Opera House is the small, white dot to the right of the bridge. Urban areas appear yellow, blue and brown. The purple areas are undeveloped areas and park lands. Manly, the famous surfing beach, is shown in yellow at the top center of the image. Runways from the Sydney Airport are the dark features that extend into Botany Bay in the lower right. Botany Bay is the site where Captain James Cook first landed his ship, Endeavour, in 1770. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on April 20, 1994, onboard the space shuttle Endeavour. The area shown is 33 kilometers by 38kilometers (20 miles by 23 miles) and is centered at 33.9 degrees south latitude, 151.2 degrees east longitude. North is toward the upper left. The colors are assigned to different radar frequenciesand polarizations as follows: red is L-band, vertically transmittedand horizontally received; green is C-band, vertically transmitted and horizontally received; and blue is C-band, vertically transmittedand received. SIR-C/X-SAR, a joint mission of the German, Italianand United States space agencies, is part of NASA's Mission to Planet Earth. #####

  17. Space Radar Image of Glascow, Missouri

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a false-color L-band image of an area near Glasgow, Missouri, centered at about 39.2 degrees north latitude and 92.8 degrees west longitude. The image was acquired using the L-band radar channel (horizontally transmitted and received and horizontally transmitted/vertically received) polarizations combined. The data were acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on orbit 50 on October 3,1994. The area shown is approximately 37 kilometers by 25 kilometers (23 miles by 16 miles). The radar data, coupled with pre-flood aerial photography and satellite data and post-flood topographic and field data, are being used to evaluate changes associated with levee breaks in landforms, where deposits formed during the widespread flooding in 1993 along the Missouri and Mississippi Rivers. The distinct radar scattering properties of farmland, sand fields and scoured areas will be used to inventory floodplains along the Missouri River and determine the processes by which these areas return to preflood conditions. The image shows one such levee break near Glasgow, Missouri. In the upper center of the radar image, below the bend of the river, is a region covered by several meters of sand, shown as dark regions. West (left) of the dark areas, a gap in the levee tree canopy shows the area where the levee failed. Radar data such as these can help scientists more accurately assess the potential for future flooding in this region and how that might impact surrounding communities. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific

  18. Space Radar Image of Mississippi Delta

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a radar image of the Mississippi River Delta where the river enters into the Gulf of Mexico along the coast of Louisiana. This multi-frequency image demonstrates the capability of the radar to distinguish different types of wetlands surfaces in river deltas. This image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on October 2, 1995. The image is centered on latitude 29.3 degrees North latitude and 89.28 degrees West longitude. The area shown is approximately 63 kilometers by 43 kilometers (39 miles by 26 miles). North is towards the upper right of the image. As the river enters the Gulf of Mexico, it loses energy and dumps its load of sediment that it has carried on its journey through the mid-continent. This pile of sediment, or mud, accumulates over the years building up the delta front. As one part of the delta becomes clogged with sediment, the delta front will migrate in search of new areas to grow. The area shown on this image is the currently active delta front of the Mississippi. The migratory nature of the delta forms natural traps for oil and the numerous bright spots along the outside of the delta are drilling platforms. Most of the land in the image consists of mud flats and marsh lands. There is little human settlement in this area due to the instability of the sediments. The main shipping channel of the Mississippi River is the broad red stripe running northwest to southeast down the left side of the image. The bright spots within the channel are ships. The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band vertically transmitted, vertically received; green is C-band vertically transmitted, vertically received; blue is X-band vertically transmitted, vertically received. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars

  19. Space Radar Image of Kilauea Volcano, Hawaii

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a deformation map of the south flank of Kilauea volcano on the big island of Hawaii, centered at 19.5 degrees north latitude and 155.25 degrees west longitude. The map was created by combining interferometric radar data -- that is data acquired on different passes of the space shuttle which are then overlayed to obtain elevation information -- acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar during its first flight in April 1994 and its second flight in October 1994. The area shown is approximately 40 kilometers by 80 kilometers (25 miles by 50 miles). North is toward the upper left of the image. The colors indicate the displacement of the surface in the direction that the radar instrument was pointed (toward the right of the image) in the six months between images. The analysis of ground movement is preliminary, but appears consistent with the motions detected by the Global Positioning System ground receivers that have been used over the past five years. The south flank of the Kilauea volcano is among the most rapidly deforming terrains on Earth. Several regions show motions over the six-month time period. Most obvious is at the base of Hilina Pali, where 10 centimeters (4 inches) or more of crustal deformation can be seen in a concentrated area near the coastline. On a more localized scale, the currently active Pu'u O'o summit also shows about 10 centimeters (4 inches) of change near the vent area. Finally, there are indications of additional movement along the upper southwest rift zone, just below the Kilauea caldera in the image. Deformation of the south flank is believed to be the result of movements along faults deep beneath the surface of the volcano, as well as injections of magma, or molten rock, into the volcano's 'plumbing' system. Detection of ground motions from space has proven to be a unique capability of imaging radar technology. Scientists hope to use deformation data acquired by SIR-C/X-SAR and future imaging

  20. Multistatic synthetic aperture radar image formation.

    PubMed

    Krishnan, V; Swoboda, J; Yarman, C E; Yazici, B

    2010-05-01

    In this paper, we consider a multistatic synthetic aperture radar (SAR) imaging scenario where a swarm of airborne antennas, some of which are transmitting, receiving or both, are traversing arbitrary flight trajectories and transmitting arbitrary waveforms without any form of multiplexing. The received signal at each receiving antenna may be interfered by the scattered signal due to multiple transmitters and additive thermal noise at the receiver. In this scenario, standard bistatic SAR image reconstruction algorithms result in artifacts in reconstructed images due to these interferences. In this paper, we use microlocal analysis in a statistical setting to develop a filtered-backprojection (FBP) type analytic image formation method that suppresses artifacts due to interference while preserving the location and orientation of edges of the scene in the reconstructed image. Our FBP-type algorithm exploits the second-order statistics of the target and noise to suppress the artifacts due to interference in a mean-square sense. We present numerical simulations to demonstrate the performance of our multistatic SAR image formation algorithm with the FBP-type bistatic SAR image reconstruction algorithm. While we mainly focus on radar applications, our image formation method is also applicable to other problems arising in fields such as acoustic, geophysical and medical imaging.

  1. Frequency Diversity for Improving Synthetic Aperture Radar Imaging

    DTIC Science & Technology

    2009-03-01

    xiii List of Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvi I. Introduction ...Improving Synthetic Aperture Radar Imaging I. Introduction 1.1 Research Motivation Synthetic aperture radar (SAR) is an active radio frequency (RF) imaging...PFA) begins with introduction of the linear frequency modulated (LFM) waveform. LFM is the most common waveform used in general radar applications [25

  2. SPace Radar Image of Fort Irwin, California

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This image of Fort Irwin in California's Mojave Desert compares interferometric radar signatures topography -- data that were obtained by multiple imaging of the same region to produce three-dimensional elevation maps -- as it was obtained on October 7-8, 1994 by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar aboard the space shuttle Endeavour. Data were acquired using the L-band (24 centimeter wavelength) and C-band (6 centimeter wavelength). The image covers an area about 25 kilometers by 70 kilometers (15.5 miles by 43 miles). North is to the lower right of the image. The color contours shown are proportional to the topographic elevation. With a wavelength one-fourth that of the L-band, the results from the C-band cycle through the color contours four times faster for a given elevation change. Detailed comparisons of these multiple frequency data over different terrain types will provide insights in the future into wavelength-dependent effects of penetration and scattering on the topography measurement accuracy. Fort Irwin is an ideal site for such detailed digital elevation model comparisons because a number of high precision digital models of the area already exist from conventional measurements as well as from airborne interferometric SAR data. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human

  3. Space Radar Image of Raco Vegetation Map

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a vegetation map of the Raco, Michigan area produced from data acquired by the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard space shuttle Endeavour. The radar image, taken on April 9, 1994, has been used by science team members at the University of Michigan to produce detailed map of land cover. This image is centered at 46.4 degrees north latitude and 84.9 degrees west longitude. The imaged area is approximately 24 by 32 kilometers (15 by 20 miles). The Raco airport, which is a decommissioned military base, is easily identified by its triangular runway structure. An edge of Lake Superior, approximately 44 kilometers (27 miles) west of Sault Sainte Marie, appears in the top right of the image. In this land cover map each 30- by 30-meter (98- by 98-foot) spot is identified as either a water surface, bare ground, short vegetation, deciduous forest, lowland conifers or upland conifers. Different types of ground cover have different effects on Earth's chemical, water and energy cycles. By cataloguing ground cover in an area, scientists expect to better understand the processes of these cycles in a specific area. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio

  4. Space Radar Image of Cape Cod, Massachusetts

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image shows the famous 'hook' of Cape Cod, Massachusetts. The Cape, which juts out into the Atlantic Ocean about 100 kilometers (62 miles) southeast of Boston, actually consists of sandy debris left behind by the great continental ice sheets when they last retreated from southern New England about 20,000 years ago. Today's landscape consists of sandy forests, fields of scrub oak and other bushes and grasses, salt marshes, freshwater ponds, as well as the famous beaches and sand dunes. In this image, thickly forested areas appear green, marshes are dark blue, ponds and sandy areas are black, and developed areas are mostly pink. The dark L-shape in the lower center is the airport runways in Hyannis, the Cape's largest town. The dark X-shape left of the center is Otis Air Force Base. The Cape Cod Canal, above and left of center, connects Buzzards Bay on the left with Cape Cod Bay on the right. The northern tip of the island of Martha's Vineyard is seen in the lower left. The tip of the Cape, in the upper right, includes the community of Provincetown, which appears pink, and the protected National Seashore areas of sand dunes that parallel the Atlantic coast east of Provincetown. Scientists are using radar images like this one to study delicate coastal environments and the effects of human activities on the ecosystem and landscape. This image was acquired by Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on April 15, 1994. The image is 81.7 kilometers by 43.1 kilometers (50.7 miles by 26.7 miles) and is centered at 41.8 degrees north latitude, 70.3 degrees west longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontally transmitted, vertically received; and blue is C-band, horizontally transmitted and received. SIR

  5. Space Radar Image of Kiluchevskoi, Volcano, Russia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an image of the area of Kliuchevskoi volcano, Kamchatka, Russia, which began to erupt on September 30, 1994. Kliuchevskoi is the blue triangular peak in the center of the image, towards the left edge of the bright red area that delineates bare snow cover. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 88th orbit on October 5, 1994. The image shows an area approximately 75 kilometers by 100 kilometers (46 miles by 62 miles) that is centered at 56.07 degrees north latitude and 160.84 degrees east longitude. North is toward the bottom of the image. The radar illumination is from the top of the image. The Kamchatka volcanoes are among the most active volcanoes in the world. The volcanic zone sits above a tectonic plate boundary, where the Pacific plate is sinking beneath the northeast edge of the Eurasian plate. The Endeavour crew obtained dramatic video and photographic images of this region during the eruption, which will assist scientists in analyzing the dynamics of the recent activity. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted and vertically received); blue represents the C-band (horizontally transmitted and vertically received). In addition to Kliuchevskoi, two other active volcanoes are visible in the image. Bezymianny, the circular crater above and to the right of Kliuchevskoi, contains a slowly growing lava dome. Tolbachik is the large volcano with a dark summit crater near the upper right edge of the red snow covered area. The Kamchatka River runs from right to left across the bottom of the image. The current eruption of Kliuchevskoi included massive ejections of gas, vapor and ash, which reached altitudes of 15,000 meters (50,000 feet). Melting snow mixed with volcanic ash triggered mud flows on the

  6. Space Radar Image of Houston, Texas

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This image of Houston, Texas, shows the amount of detail that is possible to obtain using spaceborne radar imaging. Images such as this -- obtained by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) flying aboard the space shuttle Endeavor last fall -- can become an effective tool for urban planners who map and monitor land use patterns in urban, agricultural and wetland areas. Central Houston appears pink and white in the upper portion of the image, outlined and crisscrossed by freeways. The image was obtained on October 10, 1994, during the space shuttle's 167th orbit. The area shown is 100 kilometers by 60 kilometers (62 miles by 38 miles) and is centered at 29.38 degrees north latitude, 95.1 degrees west longitude. North is toward the upper left. The pink areas designate urban development while the green-and blue-patterned areas are agricultural fields. Black areas are bodies of water, including Galveston Bay along the right edge and the Gulf of Mexico at the bottom of the image. Interstate 45 runs from top to bottom through the image. The narrow island at the bottom of the image is Galveston Island, with the city of Galveston at its northeast (right) end. The dark cross in the upper center of the image is Hobby Airport. Ellington Air Force Base is visible below Hobby on the other side of Interstate 45. Clear Lake is the dark body of water in the middle right of the image. The green square just north of Clear Lake is Johnson Space Center, home of Mission Control and the astronaut training facilities. The black rectangle with a white center that appears to the left of the city center is the Houston Astrodome. The colors in this image were obtained using the follow radar channels: red represents the L-band (horizontally transmitted, vertically received); green represents the C-band (horizontally transmitted, vertically received); blue represents the C-band (horizontally transmitted and received). Spaceborne Imaging Radar

  7. Simulation of imaging radar using graphics hardware acceleration

    NASA Astrophysics Data System (ADS)

    Peinecke, Niklas; Döhler, Hans-Ullrich; Korn, Bernd R.

    2008-04-01

    Extending previous works by Doehler and Bollmeyer we describe a new implementation of an imaging radar simulator. Our approach is based on using modern computer graphics hardware making heavy use of recent technologies like vertex and fragment shaders. Furthermore, to allow for a nearly realistic image we generate radar shadows implementing shadow map techniques in the programmable graphics hardware. The particular implementation is tailored to imitate millimeter wave (MMW) radar but could be extended for other types of radar systems easily.

  8. Space Radar Image of North Sea, Germany

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an X-band image of an oil slick experiment conducted in the North Sea, Germany. The image is centered at 54.58 degrees north latitude and 7.48 degrees east longitude. This image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on October 6, 1994, during the second flight of the spaceborne radar. The experiment was designed to differentiate between petroleum oil spills and natural slicks floating on the sea surface. Two types of petroleum oil and six types of oils resembling natural sea surface slicks were poured on the sea surface from ships and a helicopter just before the space shuttle flew over the region. At the bottom of the image is the Sylt peninsula, a famous holiday resort. Twenty-six gallons (100 liters) of diesel oil was dissipated due to wave action before the shuttle reached the site. The oil spill seen at the uppermost part of the image is about 105 gallons (400 liters) of heavy heating oil and the largest spill is about 58 gallons (220 liters) of oleyl alcohol, resembling a 'natural oil' like the remaining five spills used to imitate natural slicks that have occurred offshore from various states. The volume of these other oils spilled on the ocean surface during the five experimental spills varied from 16 gallons to 21 gallons (60 liters to 80 liters). The distance between neighboring spills was about half a mile (800 meters) at the most. The largest slick later thinned out to monomolecular sheets of about 10 microns, which is the dimension of a molecule. Oceanographers found that SIR-C/X-SAR was able to clearly distinguish the oil slicks from algae products dumped nearby. Preliminary indications are that various types of slicks may be distinguished, especially when other radar wavelengths are included in the analysis. Radar imaging of the world's oceans on a continuing basis may allow oceanographers in the future to detect and clean up oil spills much more

  9. The 94 GHz MMW imaging radar system

    NASA Technical Reports Server (NTRS)

    Alon, Yair; Ulmer, Lon

    1993-01-01

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

  10. Space Radar Image of Manaus, Brazil

    NASA Technical Reports Server (NTRS)

    1994-01-01

    These two false-color images of the Manaus region of Brazil in South America were acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar on board the space shuttle Endeavour. The image at left was acquired on April 12, 1994, and the image at right was acquired on October 3, 1994. The area shown is approximately 8 kilometers by 40 kilometers (5 miles by 25 miles). The two large rivers in this image, the Rio Negro (at top) and the Rio Solimoes (at bottom), combine at Manaus (west of the image) to form the Amazon River. The image is centered at about 3 degrees south latitude and 61 degrees west longitude. North is toward the top left of the images. The false colors were created by displaying three L-band polarization channels: red areas correspond to high backscatter, horizontally transmitted and received, while green areas correspond to high backscatter, horizontally transmitted and vertically received. Blue areas show low returns at vertical transmit/receive polarization; hence the bright blue colors of the smooth river surfaces can be seen. Using this color scheme, green areas in the image are heavily forested, while blue areas are either cleared forest or open water. The yellow and red areas are flooded forest or floating meadows. The extent of the flooding is much greater in the April image than in the October image and appears to follow the 10-meter (33-foot) annual rise and fall of the Amazon River. The flooded forest is a vital habitat for fish, and floating meadows are an important source of atmospheric methane. These images demonstrate the capability of SIR-C/X-SAR to study important environmental changes that are impossible to see with optical sensors over regions such as the Amazon, where frequent cloud cover and dense forest canopies block monitoring of flooding. Field studies by boat, on foot and in low-flying aircraft by the University of California at Santa Barbara, in collaboration with Brazil's Instituto Nacional de Pesguisas

  11. Space Radar Image of Central Plain, Oman

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Bright, arc-shaped limestone hills and complex, branching drainage patterns dominate this three-frequency space radar image of a desert area in the north central plain of Oman. The hill along the left side of the image, called Jabal Fuhud, lies just south of the town of Fuhud, which appears as small bright rectangular features. The thin red lines that can be seen radiating out from this town are roads. The 'u'-shaped hill in the right center of the image is called Jabal Natih. Layers in the limestone appear as stripes which parallel the crest of the hill. This region is an active area of petroleum production because these geological structures form natural traps for oil and gas. The branching patterns on the image are ancient drainage channels that formed when the climate in this area was much wetter. Two large dry river channels, called wadis, appear on the image. Wadi Umayri is the yellow stripe at the lower right corner of the image. A second orange-colored wadi runs from right to left below the two sets of hills. The bright yellow patterns between the wadis are areas of bedrock covered with a thin layer of sand. These rocks would not be visible in conventional satellite images or photographs. This image is centered at 22.25 degrees north latitude, 56.58 degrees east longitude. The area shown is approximately 42 kilometers by 78 kilometers (26 miles by 48 miles). North is toward the upper right. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontally transmitted and vertically received; and blue is X-band, vertically transmitted and received. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on April 10, 1994, on board the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  12. Space Radar Image of Vesuvius, Italy

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mt. Vesuvius, one of the best known volcanoes in the world primarily for the eruption that buried the Roman city of Pompeii, is shown in the center of this radar image. The central cone of Vesuvius is the dark purple feature in the center of the volcano. This cone is surrounded on the northern and eastern sides by the old crater rim, called Mt. Somma. Recent lava flows are the pale yellow areas on the southern and western sides of the cone. Vesuvius is part of a large volcanic zone which includes the Phalagrean Fields, the cluster of craters seen along the left side of the image. The Bay of Naples, on the left side of the image, is separated from the Gulf of Salerno, in the lower left, by the Sorrento Peninsula. Dense urban settlement can be seen around the volcano. The city of Naples is above and to the left of Vesuvius; the seaport of the city can be seen in the top of the bay. Pompeii is located just below the volcano on this image. The rapid eruption in 79 A.D. buried the victims and buildings of Pompeii under several meters of debris and killed more than 2,000 people. Due to the violent eruptive style and proximity to populated areas, Vesuvius has been named by the international scientific community as one of fifteen Decade Volcanoes which are being intensively studied during the 1990s. The image is centered at 40.83 degrees North latitude, 14.53 degrees East longitude. It shows an area 100 kilometers by 55 kilometers (62 miles by 34 miles.) This image was acquired on April 15, 1994 by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the Space Shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth.

  13. Space Radar Image of Manaus, Brazil

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This false-color L-band image of the Manaus region of Brazil was acquired by the Spaceborne Imaging Radar-C and X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on orbit 46 of the mission. The area shown is approximately 8 kilometers by 40 kilometers (5 by 25 miles). At the top of the image are the Solimoes and Rio Negro rivers just before they combine at Manaus to form the Amazon River. The image is centered at about 3 degrees south latitude, and 61 degrees west longitude. The false colors are created by displaying three L-band polarization channels; red areas correspond to high backscatter at HH polarization, while green areas exhibit high backscatter at HV polarization. Blue areas show low returns at VV polarization; hence the bright blue colors of the smooth river surfaces. Using this coloring scheme, green areas in the image are heavily forested, while blue areas are either cleared forest or open water. The yellow and red areas are flooded forest. Between Rio Solimoes and Rio Negro a road can be seen running from some cleared areas (visible as blue rectangles north of Rio Solimoes) north towards a tributary of Rio Negro. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio

  14. Space Radar Image of Flevoland, Netherlands

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a three-frequency false color image of Flevoland, The Netherlands, centered at 52.4 degrees north latitude, 5.4 degrees east longitude. This image was acquired by the Spaceborne Imaging Radar-C and X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard space shuttle Endeavour on April 14, 1994. It was produced by combining data from the X-band, C-band and L-band radars. The area shown is approximately 25 kilometers by 28 kilometers (15-1/2 by 17-1/2 miles). Flevoland, which fills the lower two-thirds of the image, is a very flat area that is made up of reclaimed land that is used for agriculture and forestry. At the top of the image, across the canal from Flevoland, is an older forest shown in red; the city of Harderwijk is shown in white on the shore of the canal. At this time of the year, the agricultural fields are bare soil, and they show up in this image in blue. The changes in the brightness of the blue areas are equal to the changes in roughness. The dark blue areas are water and the small dots in the canal are boats. This SIR-C/X-SAR supersite is being used for both calibration and agricultural studies. Several soil and crop ground-truth studies will be conducted during the shuttle flight. In addition, about 10calibration devices and 10 corner reflectors have been deployed to calibrate and monitor the radar signal. One of these transponders can be seen as a bright star in the lower right quadrant of the image. This false-color image was made using L-band total power in the red channel, C-band total power in the green channel, and X-band VV polarization in the blue channel. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be

  15. Space Radar Image of Kliuchevskoi, Russia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an X-band seasonal image of the Maly Semlyachik volcano, which is part of the Karymsky volcano group on Kamchatka peninsula, Russia. The image is centered at 54.2 degrees north latitude and 159.6 degrees east longitude. This image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on April 9, 1994, during the first flight of the radar system, and on September 30, 1994, during the second flight. The image channels have been assigned the following colors: red corresponds to data acquired on April 9; green corresponds to data acquired on September 30; and blue corresponds to the ratio between data from April 9 and September 30, 1994. Kamchatka is twice as large as England, Scotland and Wales combined and is home to approximately 470,000 residents. The region is characterized by a chain of volcanoes stretching 800 kilometers (500 miles) across the countryside. Many of the volcanoes, including the active Maly Semlyachik volcano in this image, have erupted during this century. But the most active period in creating the three characteristic craters of this volcano goes back 20,000, 12,000 and 2,000 years ago. The highest summit of the oldest crater reaches about 1,560 meters (1,650 feet). The radar images reveal the geological structures of craters and lava flows in order to improve scientists' knowledge of these sometimes vigorously active volcanoes. This seasonal composite also highlights the ecological differences that have occurred between April and October 1994. In April the whole area was snow-covered and, at the coast, an ice sheet extended approximately 5 kilometers (3 miles) into the sea. The area shown surrounding the volcano is covered by low vegetation much like scrub. Kamchatka also has extensive forests, which belong to the northern frontier of Taiga, the boreal forest ecosystem. This region plays an important role in the world's carbon cycle. Trees require 60 years to

  16. Space Radar Image of Altona, Manitoba, Canada

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an X-band seasonal image of the Altona test site in Manitoba, Canada, about 80 kilometers (50 miles) south of Winnipeg. The image is centered at approximately 49 degrees north latitude and 97.5 degrees west longitude. This image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on April 11, 1994, during the first flight of the radar system, and on October 2, 1994, during the second flight of SIR-C/X-SAR. The image channels have the following color assignments: red represents data acquired on April 11, 1994; green represents data acquired on October 2, 1994; blue represents the ratio of the two data sets. The test site is located in the Red River Basin and is characterized by rich farmland where a variety of crops are grown, including wheat, barley, canola, corn, sunflowers and sugar beets. This SIR-C/X-SAR research site is applying radar remote sensing to study the characteristics of vegetation and soil moisture. The seasonal comparison between the April and October 1994 data show the dramatic differences between surface conditions on the two dates. At the time of the April acquisition, almost all agricultural fields were bare and soil moisture levels were high. In October, however, soils were drier and while most crops had been harvested, some standing vegetation was still present. The areas which are cyan in color are dark in April and bright in October. These represent fields of standing biomass (amount of vegetation in a specified area) and the differences in brightness within these cyan fields represent differences in vegetation type. The very bright fields in October represent standing broadleaf crops such as corn, which had not yet been harvested. Other standing vegetation which has less biomass, such as hay and grain fields, are less bright. The magenta indicates bare soil surfaces which were wetter (brighter) in April than in October. The variations in brightness of

  17. Space Radar Image of Oberpfaffenhofen, Germany

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a false-color, three-frequency image of the Oberpfaffenhofen supersite, southwest of Munich in southern Germany, which shows the differences in what the three radar bands can see on the ground. The image covers a 27- by 36-kilometer (17- by 22-mile) area. The center of the site is 48.09 degrees north and 11.29 degrees east. The image was acquired by the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard space shuttle Endeavour on April 13, 1994, just after a heavy storm which covered the all area with 20 centimeters (8 inches) of snow. The dark area in the center of the image is Lake Ammersee. The two smaller lakes above the Ammersee are the Worthsee and the Pilsensee. On the right of the image is the tip of the Starnbergersee. The outskirt of the city of Munich can be seen at the top of the image. The Oberpfaffenhofen supersite is the major test site for X-SAR calibration and scientific experiments such as ecology, hydrology and geology. This color composite image is a three-frequency overlay. L-band total power was assigned red, the C-band total power is shown in green and the X-band VV polarization appears blue. The colors on the image stress the differences between the L-band, C-band and X-band images. If the three frequencies were seeing the same thing, the image will appear in black and white. For example, the blue areas corresponds to area for which the X-band backscatter is relatively higher than the backscatter at L-and C-band; this behavior is characteristic of clear cuts or shorter vegetation. Similarly, the forested areas have a reddish tint. Finally, the green areas seen at the southern tip of both the Ammersee and the Pilsensee lakes indicate a marshy area. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR

  18. Space Radar Image of San Rafael Glacier, Chile

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A NASA radar instrument has been successfully used to measure some of the fastest moving and most inaccessible glaciers in the world -- in Chile's huge, remote Patagonia ice fields -- demonstrating a technique that could produce more accurate predictions of glacial response to climate change and corresponding sea level changes. This image, produced with interferometric measurements made by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) flown on the Space Shuttle last fall, has provided the first detailed measurements of the mass and motion of the San Rafael Glacier. Very few measurements have been made of the Patagonian ice fields, which are the world's largest mid-latitude ice masses and account for more than 60 percent of the Southern Hemisphere's glacial area outside of Antarctica. These features make the area essential for climatologists attempting to understand the response of glaciers on a global scale to changes in climate, but the region's inaccessibility and inhospitable climate have made it nearly impossible for scientists to study its glacial topography, meteorology and changes over time. Currently, topographic data exist for only a few glaciers while no data exist for the vast interior of the ice fields. Velocity has been measured on only five of the more than 100 glaciers, and the data consist of only a few single-point measurements. The interferometry performed by the SIR-C/X-SAR was used to generate both a digital elevation model of the glaciers and a map of their ice motion on a pixel-per-pixel basis at very high resolution for the first time. The data were acquired from nearly the same position in space on October 9, 10 and 11, 1994, at L-band frequency (24-cm wavelength), vertically transmitted and received polarization, as the Space Shuttle Endeavor flew over several Patagonian outlet glaciers of the San Rafael Laguna. The area shown in these two images is 50 kilometers by 30 kilometers (30 miles by 18 miles) in

  19. Radar Imaging and Target Identification

    DTIC Science & Technology

    2005-08-24

    fast ISAR imaging algorithm, related to my work with Brett Borden, based on a suggestion from Emmanuel Cand~s. 4 Chapter 2 Current Status of Effort...were Lee Potter (Ohio State) , Miijdat 4ýetin (MIT), bf Alan Willsky (MIT), Todd Hale (AFIT), Brian Rigling (Wright State U., a for- mer student of...met Todd Hale and Marshall Greenspan (Norden Systems, Northrup Grum- man); the latter turned out to be on the same departing flight out of Huntsville

  20. Space Radar Image of Kilauea Volcano, Hawaii

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This three-dimensional image of the volcano Kilauea was generated based on interferometric fringes derived from two X-band Synthetic Aperture Radar data takes on April 13, 1994 and October 4, 1994. The altitude lines are based on quantitative interpolation of the topographic fringes. The level difference between neighboring altitude lines is 20 meters (66 feet). The ground area covers 12 kilometers by 4 kilometers (7.5 miles by 2.5 miles). The altitude difference in the image is about 500 meters (1,640 feet). The volcano is located around 19.58 degrees north latitude and 155.55 degrees west longitude. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.V.(DLR), the major partner in science, operations and data processing of X-SAR. The Instituto Ricerca Elettromagnetismo Componenti Elettronici (IRECE) at the University of Naples was a partner in the interferometry analysis.

  1. Space Radar Image of Kliuchevskoi Volcano, Russia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an image of the Kliuchevskoi volcano, Kamchatka, Russia, which began to erupt on September 30, 1994. Kliuchevskoi is the bright white peak surrounded by red slopes in the lower left portion of the image. The image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar aboard the space shuttle Endeavour on its 25th orbit on October 1, 1994. The image shows an area approximately 30 kilometers by 60 kilometers (18.5 miles by 37 miles) that is centered at 56.18 degrees north latitude and 160.78 degrees east longitude. North is toward the top of the image. The Kamchatka volcanoes are among the most active volcanoes in the world. The volcanic zone sits above a tectonic plate boundary, where the Pacific plate is sinking beneath the northeast edge of the Eurasian plate. The Endeavour crew obtained dramatic video and photographic images of this region during the eruption, which will assist scientists in analyzing the dynamics of the current activity. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted and vertically received); blue represents the C-band (horizontally transmitted and vertically received). The Kamchatka River runs from left to right across the image. An older, dormant volcanic region appears in green on the north side of the river. The current eruption included massive ejections of gas, vapor and ash, which reached altitudes of 20,000 meters (65,000 feet). New lava flows are visible on the flanks of Kliuchevskoi, appearing yellow/green in the image, superimposed on the red surfaces in the lower center. Melting snow triggered mudflows on the north flank of the volcano, which may threaten agricultural zones and other settlements in the valley to the north. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars

  2. Space Radar Image of Mammoth Mountain, California

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This false-color composite radar image of the Mammoth Mountain area in the Sierra Nevada Mountains, California, was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar aboard the space shuttle Endeavour on its 67th orbit on October 3, 1994. The image is centered at 37.6 degrees north latitude and 119.0 degrees west longitude. The area is about 39 kilometers by 51 kilometers (24 miles by 31 miles). North is toward the bottom, about 45 degrees to the right. In this image, red was created using L-band (horizontally transmitted/vertically received) polarization data; green was created using C-band (horizontally transmitted/vertically received) polarization data; and blue was created using C-band (horizontally transmitted and received) polarization data. Crawley Lake appears dark at the center left of the image, just above or south of Long Valley. The Mammoth Mountain ski area is visible at the top right of the scene. The red areas correspond to forests, the dark blue areas are bare surfaces and the green areas are short vegetation, mainly brush. The purple areas at the higher elevations in the upper part of the scene are discontinuous patches of snow cover from a September 28 storm. New, very thin snow was falling before and during the second space shuttle pass. In parallel with the operational SIR-C data processing, an experimental effort is being conducted to test SAR data processing using the Jet Propulsion Laboratory's massively parallel supercomputing facility, centered around the Cray Research T3D. These experiments will assess the abilities of large supercomputers to produce high throughput Synthetic Aperture Radar processing in preparation for upcoming data-intensive SAR missions. The image released here was produced as part of this experimental effort. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR)are part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed

  3. Space Radar Image of Weddell Sea Ice

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is the first calibrated, multi-frequency, multi-polarization spaceborne radar image of the seasonal sea-ice cover in the Weddell Sea, Antarctica. The multi-channel data provide scientists with details about the ice pack they cannot see any other way and indicates that the large expanse of sea-ice is, in fact, comprised of many smaller rounded ice floes, shown in blue-gray. These data are particularly useful in helping scientists estimate the thickness of the ice cover which is often extremely difficult to measure with other remote sensing systems. The extent, and especially thickness, of the polar ocean's sea-ice cover together have important implications for global climate by regulating the loss of heat from the ocean to the cold polar atmosphere. The image was acquired on October 3, 1994, by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour. This image is produced by overlaying three channels of radar data in the following colors: red (C-band, HH-polarization), green (L-band HV-polarization), and blue (L-band, HH-polarization). The image is oriented almost east-west with a center location of 58.2 degrees South and 21.6 degrees East. Image dimensions are 45 kilometers by 18 kilometers (28 miles by 11 miles). Most of the ice cover is composed of rounded, undeformed blue-gray floes, about 0.7 meters (2 feet) thick, which are surrounded by a jumble of red-tinged deformed ice pieces which are up to 2 meters (7 feet) thick. The winter cycle of ice growth and deformation often causes this ice cover to split apart, exposing open water or 'leads'. Ice growth within these openings is rapid due to the cold, brisk Antarctic atmosphere. Different stages of new-ice growth can be seen within the linear leads, resulting from continuous opening and closing. The blue lines within the leads are open water areas in new fractures which are roughened by wind. The bright red lines are an intermediate stage of new

  4. Nonlinear inversion of borehole-radar tomography data to reconstruct velocity and attenuation distribution in earth materials

    USGS Publications Warehouse

    Zhou, C.; Liu, L.; Lane, J.W.

    2001-01-01

    A nonlinear tomographic inversion method that uses first-arrival travel-time and amplitude-spectra information from cross-hole radar measurements was developed to simultaneously reconstruct electromagnetic velocity and attenuation distribution in earth materials. Inversion methods were developed to analyze single cross-hole tomography surveys and differential tomography surveys. Assuming the earth behaves as a linear system, the inversion methods do not require estimation of source radiation pattern, receiver coupling, or geometrical spreading. The data analysis and tomographic inversion algorithm were applied to synthetic test data and to cross-hole radar field data provided by the US Geological Survey (USGS). The cross-hole radar field data were acquired at the USGS fractured-rock field research site at Mirror Lake near Thornton, New Hampshire, before and after injection of a saline tracer, to monitor the transport of electrically conductive fluids in the image plane. Results from the synthetic data test demonstrate the algorithm computational efficiency and indicate that the method robustly can reconstruct electromagnetic (EM) wave velocity and attenuation distribution in earth materials. The field test results outline zones of velocity and attenuation anomalies consistent with the finding of previous investigators; however, the tomograms appear to be quite smooth. Further work is needed to effectively find the optimal smoothness criterion in applying the Tikhonov regularization in the nonlinear inversion algorithms for cross-hole radar tomography. ?? 2001 Elsevier Science B.V. All rights reserved.

  5. Velocity profiles inside volcanic clouds from three-dimensional scanning microwave dual-polarization Doppler radars

    NASA Astrophysics Data System (ADS)

    Montopoli, Mario

    2016-07-01

    In this work, velocity profiles within a volcanic tephra cloud obtained by dual-polarization Doppler radar acquisitions with three-dimensional (3-D) mechanical scanning capability are analyzed. A method for segmenting the radar volumes into three velocity regimes: vertical updraft, vertical fallout, and horizontal wind advection within a volcanic tephra cloud using dual-polarization Doppler radar moments is proposed. The horizontal and vertical velocity components within the regimes are retrieved using a novel procedure that makes assumptions concerning the characteristics of the winds inside these regimes. The vertical velocities retrieved are combined with 1-D simulations to derive additional parameters including particle fallout, mass flux, and particle sizes. The explosive event occurred on 23 November 2013 at the Mount Etna volcano (Sicily, Italy), is considered a demonstrative case in which to analyze the radar Doppler signal inside the tephra column. The X-band radar (3 cm wavelength) in the Catania, Italy, airport observed the 3-D scenes of the Etna tephra cloud ~32 km from the volcano vent every 10 min. From the radar-derived vertical velocity profiles of updraft, particle fallout, and horizontal transportation, an exit velocity of 150 m/s, mass flux rate of 1.37 • 107 kg/s, particle fallout velocity of 18 m/s, and diameters of precipitating tephra particles equal to 0.8 cm are estimated on average. These numbers are shown to be consistent with theoretical 1-D simulations of plume dynamics and local reports at the ground, respectively. A thickness of 3 ± 0.36 km for the downwind ash cloud is also inferred by differentiating the radar-derived cloud top and the height of transition between the convective and buoyancy regions, the latter being inferred by the estimated vertical updraft velocity profile. The unique nature of the case study as well as the novelty of the segmentation and retrieval methods presented potentially give new insights into the

  6. On the consistency of the SuperDARN radar velocity and E × B plasma drift

    NASA Astrophysics Data System (ADS)

    Koustov, A. V.; Lavoie, D. B.; Varney, R. H.

    2016-11-01

    Joint observations of the Rankin Inlet (RKN) and Inuvik Super Dual Auroral Radar Network (SuperDARN) HF radars and Resolute Bay incoherent scatter radar (RISR) are used to assess consistency in their plasma flow velocity measurements. The analysis covers more than 500 h of successful concurrent measurements. We demonstrate that, overall, the radars show close velocities, although there were minor differences including SuperDARN velocity underestimation, in line with previous publications, and the persistent occurrence of measurements with a SuperDARN velocity magnitude above the RISR velocity magnitude. We argue that, for one event, the velocity overestimation occurs owing to echo detection from a laterally refracted RKN beam while, generally, the effect should be fairly wide-spread in SuperDARN data because of microstructures with enhanced electron density in the scattering volume that might have either weak irregularities or increased local electric fields. We estimate that the correction of RKN velocity data by considering the effect of the index of refraction improves RKN-RISR velocity agreement but only for 63% of points. This implies that care should be exercised when attempting to correct raw SuperDARN velocity data by the index of refraction.

  7. Local wavefield velocity imaging for damage evaluation

    NASA Astrophysics Data System (ADS)

    Chia, Chen Ciang; Gan, Chia Sheng; Mustapha, F.

    2017-02-01

    Ultrasonic Propagation Imaging or Acoustic Wavefield Imaging has been widely used to evaluate structural damages and internal features. Inspecting complete wavefield time history for damage identification is tedious and error-prone. A more effective way is by extracting damage-related information into a single image. A wavefield velocity imaging method that maps the local estimates of group or phase velocity is proposed. Actual velocity values rather than arbitrarily-scaled intensities are mapped, enabling damage sizing without the need of supervised training or inspecting wavefield propagation video. Performance of the proposed method was tested by inspecting a 100 mm by 100 mm area of a 2 mm thick stainless steel specimen. Local phase velocity maps of A0 mode showed a half-thickness hole of 2 mm diameter as significant change in local phase velocity from the nominal 2 m/ms. Full width at half maximum of relevant velocity profiles proved the accuracy and consistency of the damage sizing.

  8. Space Radar Image of Lisbon, Portugal

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This radar image of Lisbon, Portugal illustrates the different land use patterns that are present in coastal Portugal. Lisbon, the national capital, lies on the north bank of the Rio Tejo where the river enters the Atlantic Ocean. The city center appears as the bright area in the center of the image. The green area west of the city center is a large city park called the Parque Florestal de Monsanto. The Lisbon Airport is visible east of the city. The Rio Tejo forms a large bay just east of the city. Many agricultural fields are visible as a patchwork pattern east of the bay. Suburban housing can be seen on the southern bank of the river. Spanning the river is the Ponte 25 de Abril, a large suspension bridge similar in architecture to San Francisco's Golden Gate Bridge. The image was acquired on April 19, 1994 and is centered at 38.8 degrees north latitude, 9.2 degrees west longitude. North is towards the upper right. The image is 50 kilometers by 30 kilometers (31 miles by 19 miles). The colors in this image represent the following radar channels and polarizations: red is L-band, horizontally transmitted and received; green is L-band, horizontally transmitted and vertically received; and blue is C-band, horizontally transmitted and vertically received. SIR-C/X-SAR, a joint mission of the German, Italian, and the United States space agencies, is part of NASA's Mission to Planet Earth.

  9. Space Radar Image of Safsaf, North Africa

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a false-color image of the uninhabited Safsaf Oasis in southern Egypt near the Egypt/Sudan border. It was produced from data obtained from the L-band and C-band radars that are part of the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard space shuttle Endeavour on April 9, 1994. The image is centered at 22 degree north latitude, 29 degrees east longitude. It shows detailed structures of bedrock; the dark blue sinuous lines are braided channels that occupy part of an old broad river valley. On the ground and in optical photographs, this big valley and the channels in it are invisible because they are entirely covered by windblown sand. Some of these same channels were observed in SIR-A images in 1981. It is hypothesized that the large valley was carved by one of several ancient predecessor rivers that crossed this part of North Africa, flowing westward, tens of millions of years before the Nile River existed. The Nile flows north about 300 kilometers (200 miles) to the east. The small channels are younger, and probably formed during relatively wet climatic periods within the past few hundred thousand years. This image shows that the channels are in a river valley located in an area where U.S. Geological Survey geologists and archeologists discovered an unusual concentration of hand axes (stone tools) used by Early Man (Homo erectus) hundreds of thousands of years ago. The image clearly shows that in wetter times, the valley would have supported game animals and vegetation. Today, as a result of climate change, the area in uninhabited and lacks water except fora few scattered oases. This color composite image was produced from C-band and L-band horizontal polarization images. The C-band image was assigned red, the L-band (HH) polarization image is shown in green, and the ratio of these two images (LHH/CHH) appears in blue. The primary and composite colors on the image indicate the degree to which the C-band, H-band, their

  10. Space Radar Image of Karisoke & Virunga Volcanoes

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a false-color composite of Central Africa, showing the Virunga volcano chain along the borders of Rwanda, Zaire and Uganda. This area is home to the endangered mountain gorillas. The image was acquired on October 3, 1994, on orbit 58 of the space shuttle Endeavour by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR). In this image red is the L-band (horizontally transmitted, vertically received) polarization; green is the C-band (horizontally transmitted and received) polarization; and blue is the C-band (horizontally transmitted and received) polarization. The area is centered at about 2.4 degrees south latitude and 30.8 degrees east longitude. The image covers an area 56 kilometers by 70 kilometers (35 miles by 43 miles). The dark area at the top of the image is Lake Kivu, which forms the border between Zaire (to the right) and Rwanda (to the left). In the center of the image is the steep cone of Nyiragongo volcano, rising 3,465 meters (11,369 feet) high, with its central crater now occupied by a lava lake. To the left are three volcanoes, Mount Karisimbi, rising 4,500 meters (14,800 feet) high; Mount Sabinyo, rising 3,600 meters (12,000 feet) high; and Mount Muhavura, rising 4,100 meters (13,500 feet) high. To their right is Nyamuragira volcano, which is 3,053 meters (10,017 feet) tall, with radiating lava flows dating from the 1950s to the late 1980s. These active volcanoes constitute a hazard to the towns of Goma, Zaire and the nearby Rwandan refugee camps, located on the shore of Lake Kivu at the top left. This radar image highlights subtle differences in the vegetation of the region. The green patch to the center left of the image in the foothills of Karisimbi is a bamboo forest where the mountain gorillas live. The vegetation types in this area are an important factor in the habitat of mountain gorillas. Researchers at Rutgers University in New Jersey and the Dian Fossey Gorilla Fund in London will use this data to produce

  11. Space Radar Image of Oetzal, Austria

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This image is a false-color composite of Oetzal, Austria located in the Central Alps centered at 46.8 degrees north latitude, 10.70 degrees east longitude, at the border between Switzerland (top), Italy (left) and Austria (right and bottom). The area shown is 50 kilometers (30 miles) south of Innsbruck, Austria. This image was acquired by the Spaceborne Imaging Radar-C and X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 14th orbit. Oetztal is a SIR-C/X-SAR hydrology supersite. Approximately one quarter of this image is covered by glaciers, the largest of which, Gepatschferner, is visible as a triangular yellow patch in the center of the scene. The summits of the main peaks reach elevations between 3,500 and 3,768 meters (11,500 and 12,362 feet) above sea level. The tongues of the glaciers are descending from elevated plateaus down into narrow valleys which were formed during the last ice age. This color image was produced in C-band using multi-polarization information (red=CHV, green=CVV,blue=CVV/CHV). The blue areas are lakes (Gepatsch dam at center right; Lake Muta at top right) and glacier ice. The yellow areas are slopes facing the radar and areas of dry snow. Purple corresponds to slopes facing away from the radar. Yellow in the valley bottom corresponds to tree covered areas. There is 30 to 50 centimeters (12 to 20 inches) of dry, fresh snow on the glaciers, and about 10 centimeters (4 inches) in the valley at the city of Vent, Austria (center). At these data were taken, the weather was cold, with snow and thick fog. The entire area would appear white to an optical sensor because it is all covered under a winter snowpack. Researchers are interested in Oetztal because knowing how glaciers shrink and grow over time is an important indication of climatic change. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth (MTPE). The radars illuminate Earth with

  12. Space Radar Image of Taal Volcano, Philippines

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an image of Taal volcano, near Manila on the island of Luzon in the Philippines. The black area in the center is Taal Lake, which nearly fills the 30-kilometer-diameter (18-mile) caldera. The caldera rim consists of deeply eroded hills and cliffs. The large island in Taal Lake, which itself contains a crater lake, is known as Volcano Island. The bright yellow patch on the southwest side of the island marks the site of an explosion crater that formed during a deadly eruption of Taal in 1965. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 78th orbit on October 5, 1994. The image shows an area approximately 56 kilometers by 112 kilometers (34 miles by 68 miles) that is centered at 14.0 degrees north latitude and 121.0 degrees east longitude. North is toward the upper right of the image. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted and vertically received); blue represents the C-band (horizontally transmitted and vertically received). Since 1572, Taal has erupted at least 34 times. Since early 1991, the volcano has been restless, with swarms of earthquakes, new steaming areas, ground fracturing, and increases in water temperature of the lake. Volcanologists and other local authorities are carefully monitoring Taal to understand if the current activity may foretell an eruption. Taal is one of 15 'Decade Volcanoes' that have been identified by the volcanology community as presenting large potential hazards to population centers. The bright area in the upper right of the image is the densely populated city of Manila, only 50 kilometers (30 miles) north of the central crater. Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth

  13. Space Radar Image of Kilauea, Hawaii

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This color composite C-band and L-band image of the Kilauea volcano on the Big Island of Hawaii was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) flying on space shuttle Endeavour. The city of Hilo can be seen at the top. The image shows the different types of lava flows around the crater Pu'u O'o. Ash deposits which erupted in 1790 from the summit of Kilauea volcano show up as dark in this image, and fine details associated with lava flows which erupted in 1919 and 1974 can be seen to the south of the summit in an area called the Ka'u Desert. In addition, the other historic lava flows created in 1881 and 1984 from Mauna Loa volcano (out of view to the left of this image) can be easily seen despite the fact that the surrounding area is covered by forest. Such information will be used to map the extent of such flows, which can pose a hazard to the subdivisions of Hilo. Highway 11 is the linear feature running from Hilo to the Kilauea volcano. The Kilauea volcano has been almost continuously active for more than the last 11 years. Field teams that were on the ground specifically to support these radar observations report that there was vigorous surface activity about 400 meters (one-quarter mile) inland from the coast. A moving lava flow about 200 meters (660 feet) in length was observed at the time of the shuttle overflight, raising the possibility that subsequent images taken during this mission will show changes in the landscape. This image is centered at 19.2 degrees north latitude and 155.2 degrees west longitude. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific

  14. Distributed MIMO Radar for Imaging and High Resolution Target Localization

    DTIC Science & Technology

    2012-02-02

    28-2012 Final Report 04/15/2009 - 11/30/2011 Distributed MIMO Radar for Imaging and High Resolution Target Localization FA9550-09-1-0303 Alexander M...randomly placed sensors. MIMO radar, High-Resolution radar 19 Distributed MIMO Radar for Imaging and High Resolution Target Localization Air Force Office...configured with its antennas collocated [6] or distributed over an area [7, 8]. We refer to radio elements of a MIMO radar as nodes. Nodes may be equipped

  15. SPace Radar Image of Mt. Pinatubo, Philippines

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a false color L-band and C-band image of the area around Mount Pinatubo in the Philippines, centered at about 15 degrees north latitude, 120.5 degrees east longitude. This image was acquired by the Spaceborne Imaging Radar-C and X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on orbit 78 on April 13, 1994. The false-color composite is made by displaying the L-band HH return in red, the L-band HV return in green and the C-band HV return in blue. The area shown is approximately 45 by 68 kilometers (28 by 42 miles). The main volcanic crater on Mount Pinatubo produced by the June 1991 eruptions, and the steep slopes on the upper flanks of the volcano, are easily seen in this image. The red color on the high slopes show the rougher ash deposited during the 1991 eruption. The dark drainages are the smooth mudflows which continue to flood the river valleys after heavy rain. Radar images such as this one can be used to identify the areas flooded by mudflows, which are difficult to distinguish visually, and to assess the rate at which the erosion and deposition continues. A key aspect of the second SIR-C/X-SAR mission in August 1994 will be to collect a second image of Pinatubo during the summer monsoon season -- new mudflows will have occurred -- and to evaluate the short-term changes. The 1991 eruption of Mount Pinatubo in the Philippines is well known for its near-global effects on the atmosphere and climate due to the large amount of sulfur dioxide that was injected into the upper atmosphere. What is less widely known is that even today the volcano continues to be a major hazard to the people who have returned to the area around the volcano. Dangerous mudflows (called 'lahars') are often generated by heavy rains, and these can still sweep down river valleys and wash out roads and villages, or bury low lying areas in several meters of mud and volcanic debris. These mudflows will continue to be a severe hazard around Pinatubo for

  16. Space Radar Image of Colombian Volcano

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a radar image of a little known volcano in northern Colombia. The image was acquired on orbit 80 of space shuttle Endeavour on April 14, 1994, by the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR). The volcano near the center of the image is located at 5.6 degrees north latitude, 75.0 degrees west longitude, about 100 kilometers (65 miles) southeast of Medellin, Colombia. The conspicuous dark spot is a lake at the bottom of an approximately 3-kilometer-wide (1.9-mile) volcanic collapse depression or caldera. A cone-shaped peak on the bottom left (northeast rim) of the caldera appears to have been the source for a flow of material into the caldera. This is the northern-most known volcano in South America and because of its youthful appearance, should be considered dormant rather than extinct. The volcano's existence confirms a fracture zone proposed in 1985 as the northern boundary of volcanism in the Andes. The SIR-C/X-SAR image reveals another, older caldera further south in Colombia, along another proposed fracture zone. Although relatively conspicuous, these volcanoes have escaped widespread recognition because of frequent cloud cover that hinders remote sensing imaging in visible wavelengths. Four separate volcanoes in the Northern Andes nations ofColombia and Ecuador have been active during the last 10 years, killing more than 25,000 people, including scientists who were monitoring the volcanic activity. Detection and monitoring of volcanoes from space provides a safe way to investigate volcanism. The recognition of previously unknown volcanoes is important for hazard evaluations because a number of major eruptions this century have occurred at mountains that were not previously recognized as volcanoes. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of

  17. Space Radar Image of Mt. Rainer, Washington

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a radar image of Mount Rainier in Washington state. The volcano last erupted about 150 years ago and numerous large floods and debris flows have originated on its slopes during the last century. Today the volcano is heavily mantled with glaciers and snowfields. More than 100,000 people live on young volcanic mudflows less than 10,000 years old and, consequently, are within the range of future, devastating mudslides. This image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 20th orbit on October 1, 1994. The area shown in the image is approximately 59 kilometers by 60 kilometers (36.5 miles by 37 miles). North is toward the top left of the image, which was composed by assigning red and green colors to the L-band, horizontally transmitted and vertically, and the L-band, horizontally transmitted and vertically received. Blue indicates the C-band, horizontally transmitted and vertically received. In addition to highlighting topographic slopes facing the space shuttle, SIR-C records rugged areas as brighter and smooth areas as darker. The scene was illuminated by the shuttle's radar from the northwest so that northwest-facing slopes are brighter and southeast-facing slopes are dark. Forested regions are pale green in color; clear cuts and bare ground are bluish or purple; ice is dark green and white. The round cone at the center of the image is the 14,435-foot (4,399-meter) active volcano, Mount Rainier. On the lower slopes is a zone of rock ridges and rubble (purple to reddish) above coniferous forests (in yellow/green). The western boundary of Mount Rainier National Park is seen as a transition from protected, old-growth forest to heavily logged private land, a mosaic of recent clear cuts (bright purple/blue) and partially regrown timber plantations (pale blue). The prominent river seen curving away from the mountain at the top of the image (to the northwest) is the

  18. Probability of acquisition of three-dimensional imaging laser radar

    NASA Astrophysics Data System (ADS)

    Dong, Li-jun; Zhu, Shao-lan; Sun, Chuan-dong; Gao, Cun-xiao; Song, Zhi-yuan

    2011-06-01

    Three-dimensional imaging laser radar (3-D ladar) is widely used in area of modern military, scientific research, agriculture and industry. Because of its many features such as angle-angle-range capturing, high resolution, anti-jamming ability and no multipath effect ,but it has to scan for target searching, acquiring and tracking. This paper presents a novel probability model of target acquiring which provides a theoretical basis for optimizing the scanning mechanism. The model combines space and time, target moving velocity and ladar scanning velocity together. Then the optimum scanning mechanism to obtain the maximum probability of acquisition and associated with different targets can be gained. The result shows that this model provides a method to optimize parameter for designing of the scanner.

  19. Space Radar Image of Hong Kong, China

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an X-SAR image spanning an area of approximately 20 kilometers by 40 kilometers (12 miles by 25 miles) of the island of Hong Kong, the Kowloon Peninsula and the new territories in southern China, taken by the imaging radar on board the space shuttle Endeavour on October 4, 1994. North is toward the top left corner of the image. The Kaitak Airport runway on Kowloon Peninsula (center right of image) was built on reclaimed land and extends almost 3 kilometers (nearly 2 miles) into Victoria Harbor. To the south of the harbor lies the island of Hong Kong. The bright areas around the harbor are the major residential and business districts. Housing more than six million residents, Hong Kong is the most densely populated area in the world. The large number of objects visible in the harbor and surrounding waters are a variety of sea-going vessels, anchored in one of the busiest seaports in the Far East. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.V.(DLR), the major partner in

  20. Analysis of radar images by means of digital terrain models

    NASA Technical Reports Server (NTRS)

    Domik, G.; Leberl, F.; Kobrick, M.

    1984-01-01

    It is pointed out that the importance of digital terrain models in the processing, analysis, and interpretation of remote sensing data is increasing. In investigations related to the study of radar images, digital terrain models can have a particular significance, because radar reflection is a function of the terrain characteristics. A procedure for the analysis and interpretation of radar images is discussed. The procedure is based on a utilization of computer simulation which makes it possible to produce simulated radar images on the basis of a digital terrain model. The simulated radar images are used for the geometric and radiometric rectification of real radar images. A description of the employed procedures is provided, and the obtained results are discussed, taking into account a test area in Northern California.

  1. Integrating Radar Image Data with Google Maps

    NASA Technical Reports Server (NTRS)

    Chapman, Bruce D.; Gibas, Sarah

    2010-01-01

    A public Web site has been developed as a method for displaying the multitude of radar imagery collected by NASA s Airborne Synthetic Aperture Radar (AIRSAR) instrument during its 16-year mission. Utilizing NASA s internal AIRSAR site, the new Web site features more sophisticated visualization tools that enable the general public to have access to these images. The site was originally maintained at NASA on six computers: one that held the Oracle database, two that took care of the software for the interactive map, and three that were for the Web site itself. Several tasks were involved in moving this complicated setup to just one computer. First, the AIRSAR database was migrated from Oracle to MySQL. Then the back-end of the AIRSAR Web site was updated in order to access the MySQL database. To do this, a few of the scripts needed to be modified; specifically three Perl scripts that query that database. The database connections were then updated from Oracle to MySQL, numerous syntax errors were corrected, and a query was implemented that replaced one of the stored Oracle procedures. Lastly, the interactive map was designed, implemented, and tested so that users could easily browse and access the radar imagery through the Google Maps interface.

  2. Space Radar Image of Mammoth, California

    NASA Technical Reports Server (NTRS)

    1999-01-01

    These two images were created using data from the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR). The image on the left is a false-color composite of the Mammoth Mountain area in California's Sierra Nevada Mountains centered at 37.6 degrees north, 119.0 degrees west. It was acquired on-board the space shuttle Endeavour on its 67th orbit on April 13, 1994. In the image on the left, red is C-band HV-polarization, green is C-band HH-polarization and blue is the ratio of C-band VV-polarization to C-band HV-polarization. On the right is a classification map of the surface features which was developed by SIR-C/X-SAR science team members at the University of California, Santa Barbara. The area is about 23 by 46 kilometers (14 by 29 miles). In the classification image, the colors represent the following surfaces: White snow Red frozen lake, covered by snow Brown bare ground Blue lake (open water) Yellow short vegetation (mainly brush) Green sparse forest Dark green dense forest Maps like this one are helpful to scientists studying snow wetness and snow water equivalent in the snow pack. Across the globe, over major portions of the middle and high latitudes, and at high elevations in the tropical latitudes, snow and alpine glaciers are the largest contributors to run-off in rivers and to ground-water recharge. Snow hydrologists are using radar in an attempt to estimate both the quantity of water held by seasonal snow packs and the timing of snow melt. Snow and ice also play important roles in regional climates; understanding the processes in seasonal snow cover is also important for studies of the chemical balance of alpine drainage basins. SIR-C/X-SAR is a powerful tool because it is sensitive to most snow pack conditions and is less influenced by weather conditions than other remote sensing instruments, such as the Landsat satellite. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth

  3. Space Radar Image of Bebedauro, Brazil, seasonal

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an X-band image showing seasonal changes at the hydrological test site of Bebedouro in Brazil. The image is centered at 9 degrees south latitude and 40.2 degrees west longitude. This image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on April 10, 1994, during the first flight of the radar system, and on October 1, 1994, during the second mission. The swath width is approximately 16.5 kilometers (10.5 miles) wide. The image channels have the following color assignments: red represents data acquired on April 10; green represents data acquired on October 1; blue corresponds to the ratio of the two data sets. Agriculture plays an important economic and social role in Brazil. One of the major problems related to Brazilian agriculture is estimating the size of planting areas and their productivity. Due to cloud cover and the rainy season, which occurs from November through April, optical and infrared Earth observations are seldom used to survey the region. An additional goal of monitoring this region is to watch the floodplains of rivers like Rio Sao Francisco in order to determine suitable locations for additional agricultural fields. This area belongs to the semi-arid northeastern region of Brazil, where estimates have suggested that about 10 times more land could be used for agriculture, including some locations which could be used for irrigation projects. Monitoring of soil moisture during the important summer crop season is of high priority for the future development and productivity of this region. In April the area was covered with vegetation because of the moisture of the soil and only small differences could be seen in X-band data. In October the run-off channels of this hilly region stand out quite clearly because the greenish areas indicated much less soil moisture and water content in plants. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR

  4. Radar imaging of intense nonlinear Ekman divergence

    NASA Astrophysics Data System (ADS)

    Liu, Guoqiang; Perrie, William; Kudryavtsev, Vladimir; He, Yijun; Shen, Hui; Zhang, Biao; Hu, Haibo

    2016-09-01

    In general, given an oceanic thermal front, there is a strong positive correlation between sea surface temperature (SST) gradients and surface winds, and the marine atmospheric boundary layer is unstable over the warm side of the oceanic thermal front. The Gulf Stream is a notable example of an oceanic thermal front, and its warm side is often detected as enhanced backscatter in synthetic aperture radar (SAR) images. However, in some "anomalous" SAR images, low backscatter is sometimes observed on the warm side of the front, which seems inconsistent. Therefore, we propose a mechanism to interpret the generation of the low backscatter, based on interactions between ocean surface wind waves and intense nonlinear Ekman divergence. This mechanism is verified by showing that patterns in an observed anomalous SAR image are in good agreement with those in the simulated radar signature. In addition, this methodology and analysis demonstrate that SAR is potentially important for detecting and diagnosing small scale air-sea interactions and upper ocean dynamics with strong vertical transports induced by submesoscale processes.

  5. Space radar image of Sunbury, Pennsylvania

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Scientists are using this radar image of the area surrounding Sunbury, Pennsylvania to study the geologic structure and land use patterns in the Appalachian Valley and Ridge province. This image was collected on October 6, 1994 by the Spaceborne Imaging Radar-C/ X-Band Synthetic Aperture Radar (SIR-C/X-SAR) on orbit 102 of the space shuttle Endeavour. The image is centered on latitude 40.85 degrees North latitude and 76.79 degrees West longitude. The area shown is approximately 30.5 km by 38 km.(19 miles by 24 miles). North is towards the upper right of the image. The Valley and Ridge province occurs in the north-central Appalachians, primarily in Pennsylvania, Maryland, and Virginia. It is an area of adjacent valleys and ridges that formed when the Appalachian mountain were created some 370 to 390 million years ago. During the continental collision that formed the Appalachians, the rocks in this area were pushed from the side and buckled much like a rug when pushed from one end. Subsequent erosion has produced the landscape we see in this image. The more resistant rocks, such as sandstone, form the tops of the ridges which appear as forested greenish areas on this image. The less resistant rocks, such as limestone, form the lower valleys which are cleared land and farm fields and are purple in this image. Smaller rivers and streams in the area flow along the valleys and in places cut across the ridges in 'water gaps.' In addition to defining the geography of this region, the Valley and Ridge province also provides this area with natural resources. The valleys provide fertile farmland and the folded mountains form natural traps for oil and gas accumulation; coal deposits are also found in the mountains. The colors in the image are assigned to different frequencies and polarizations of the SIR-C radar as follows: red is L-band horizontally transmitted, horizontally received; green is L-band horizontally transmitted, vertically received; blue is C-band horizontally

  6. Space Radar Image of Prince Albert, Canada

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a false-color composite of Prince Albert, Canada, centered at 53.91 north latitude and 104.69 west longitude. This image was acquired by the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar(SIR-C/X-SAR) aboard space shuttle Endeavour on its 20th orbit. The area is located 40 kilometers (25 miles) north and 30 kilometers (20 miles) east of the town of Prince Albert in the Saskatchewan province of Canada. The image covers the area east of the Candle lake, between gravel surface highways 120 and 106 and west of 106. The area in the middle of the image covers the entire Nipawin (Narrow Hills) provincial park. The look angle of the radar is 30 degrees and the size of the image is approximately 20 kilometers by 50 kilometers (12 by 30 miles). The image was produced by using only the L-band. The three polarization channels HH, HV and VV are illustrated by red, green and blue respectively. The changes in the intensity of each color are related to various surface conditions such as variations in forest stands, frozen or thawed condition of the surface, disturbances (fire and deforestation), and areas of regrowth. Most of the dark areas in the image are the ice-covered lakes in the region. The dark area on the top right corner of the image is the white Gull Lake north of the intersection of highway 120 and 913. The right middle part of the image shows Lake Ispuchaw and Lower Fishing Lake. The deforested areas are also shown by dark areas in the image. Since most of the logging practice at the Prince Albert area is around the major highways, the deforested areas can be easily detected as small geometrically shaped dark regions along the roads. At the time of the SIR-C/X-SAR overpass a major part of the forest is either frozen or undergoing the spring thaw. The L-band HH shows a high return in the jack pine forest. The reddish areas in the image are old jack pine forest, 12 to 17 meters (40to 55 feet) in height and 60 to 75 years old. The orange

  7. A study of image quality for radar image processing. [synthetic aperture radar imagery

    NASA Technical Reports Server (NTRS)

    King, R. W.; Kaupp, V. H.; Waite, W. P.; Macdonald, H. C.

    1982-01-01

    Methods developed for image quality metrics are reviewed with focus on basic interpretation or recognition elements including: tone or color; shape; pattern; size; shadow; texture; site; association or context; and resolution. Seven metrics are believed to show promise as a way of characterizing the quality of an image: (1) the dynamic range of intensities in the displayed image; (2) the system signal-to-noise ratio; (3) the system spatial bandwidth or bandpass; (4) the system resolution or acutance; (5) the normalized-mean-square-error as a measure of geometric fidelity; (6) the perceptual mean square error; and (7) the radar threshold quality factor. Selective levels of degradation are being applied to simulated synthetic radar images to test the validity of these metrics.

  8. Space Radar Image of Moscow, Russia

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a vertically polarized L-band image of the southern half of Moscow, an area which has been inhabited for 2,000 years. The image covers a diameter of approximately 50 kilometers (31 miles) and was taken on September 30, 1994 by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar aboard the space shuttle Endeavour. The city of Moscow was founded about 750 years ago and today is home to about 8 million residents. The southern half of the circular highway (a road that looks like a ring) can easily be identified as well as the roads and railways radiating out from the center of the city. The city was named after the Moskwa River and replaced Russia's former capital, St. Petersburg, after the Russian Revolution in 1917. The river winding through Moscow shows up in various gray shades. The circular structure of many city roads can easily be identified, although subway connections covering several hundred kilometers are not visible in this image. The white areas within the ring road and outside of it are buildings of the city itself and it suburban towns. Two of many airports are located in the west and southeast of Moscow, near the corners of the image. The Kremlin is located north just outside of the imaged city center. It was actually built in the 16th century, when Ivan III was czar, and is famous for its various churches. In the surrounding area, light gray indicates forests, while the dark patches are agricultural areas. The various shades from middle gray to dark gray indicate different stages of harvesting, ploughing and grassland. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific

  9. Space Radar Image of Yellowstone Park, Wyoming

    NASA Technical Reports Server (NTRS)

    1994-01-01

    These two radar images show the majestic Yellowstone National Park, Wyoming, the oldest national park in the United States and home to the world's most spectacular geysers and hot springs. The region supports large populations of grizzly bears, elk and bison. In 1988, the park was burned by one of the most widespread fires to occur in the northern Rocky Mountains in the last 50 years. Surveys indicated that 793,880 acres of land burned. Of that, 41 percent was burned forest, with tree canopies totally consumed by the fire; 35 percent was a combination of unburned, scorched and blackened trees; 13 percent was surface burn under an unburned canopy; 6 percent was non-forest burn; and 5 percent was undifferentiated burn. Six years later, the burned areas are still clearly visible in these false-color radar images obtained by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar on board the space shuttle Endeavour. The image at the left was obtained using the L-band radar channel, horizontally received and vertically transmitted, on the shuttle's 39th orbit on October 2, 1994. The area shown is 45 kilometers by 71 kilometers (28 miles by 44 miles) in size and centered at 44.6 degrees north latitude, 110.7 degrees west longitude. North is toward the top of the image (to the right). Most trees in this area are lodge pole pines at different stages of fire succession. Yellowstone Lake appears as a large dark feature at the bottom of the scene. At right is a map of the forest crown, showing its biomass, or amount of vegetation, which includes foliage and branches. The map was created by inverting SIR-C data and using in situ estimates of crown biomass gathered by the Yellowstone National Biological Survey. The map is displayed on a color scale from blue (rivers and lakes with no biomass) to brown (non-forest areas with crown biomass of less than 4 tons per hectare) to light brown (areas of canopy burn with biomass of between 4 and 12 tons per hectare). Yellow

  10. Space Radar Image of Yellowstone Park, Wyoming

    NASA Technical Reports Server (NTRS)

    1994-01-01

    These two radar images show the majestic Yellowstone National Park, Wyoming, the oldest national park in the United States and home to the world's most spectacular geysers and hot springs. The region supports large populations of grizzly bears, elk and bison. In 1988, the park was burned by one of the most widespread fires to occur in the northern Rocky Mountains in the last 50 years. Surveys indicated that 793,880 acres of land burned. Of that, 41 percent was burned forest, with tree canopies totally consumed by the fire; 35 percent was a combination of unburned, scorched and blackened trees; 13 percent was surface burn under an unburned canopy; 6 percent was non-forest burn; and 5 percent was undifferentiated burn. Six years later, the burned areas are still clearly visible in these false-color radar images obtained by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar on board the space shuttle Endeavour. The image at the left was obtained using the L-band radar channel, horizontally received and vertically transmitted, on the shuttle's 39th orbit on October 2, 1994. The area shown is 45 kilometers by 71 kilometers (28 miles by 44 miles) in size and centered at 44.6 degrees north latitude, 110.7 degrees west longitude. North is toward the top of the image (to the right). Most trees in this area are lodge pole pines at different stages of fire succession. Yellowstone Lake appears as a large dark feature at the bottom of the scene. At right is a map of the forest crown, showing its biomass, or amount of vegetation, which includes foliage and branches. The map was created by inverting SIR-C data and using in situ estimates of crown biomass gathered by the Yellowstone National Biological Survey. The map is displayed on a color scale from blue (rivers and lakes with no biomass) to brown (non-forest areas with crown biomass of less than 4 tons per hectare) to light brown (areas of canopy burn with biomass of between 4 and 12 tons per hectare). Yellow

  11. Radar Images of Asteroid 4179 Toutatis

    NASA Technical Reports Server (NTRS)

    Ostro, Steven J.; Hudson, R. Scott; Jurgens, Raymond F.; Rosema, Keith D.; Campbell, Donald B.; Yeomans, Donald K.; Chandler, John F.; Giorgini, Jon D.; Winkler, Ron; Rose, Randy

    1995-01-01

    Delay-Doppler images of the Earth-crossing asteroid 4179 Toutatis achieve resolutions as fine as 125 nanoseconds (19 meters in range) and 8.3 millihertz (0.15 millimeter per second in radial velocity) and place hundreds to thousands of pixels on the asteroid, which appears to be several kilometers long, topographically bifurcated, and heavily cratered. The image sequence reveals Toutatis to be in an extremely slow, non-principal axis rotation state.

  12. Advanced methods in synthetic aperture radar imaging

    NASA Astrophysics Data System (ADS)

    Kragh, Thomas

    2012-02-01

    For over 50 years our world has been mapped and measured with synthetic aperture radar (SAR). A SAR system operates by transmitting a series of wideband radio-frequency pulses towards the ground and recording the resulting backscattered electromagnetic waves as the system travels along some one-dimensional trajectory. By coherently processing the recorded backscatter over this extended aperture, one can form a high-resolution 2D intensity map of the ground reflectivity, which we call a SAR image. The trajectory, or synthetic aperture, is achieved by mounting the radar on an aircraft, spacecraft, or even on the roof of a car traveling down the road, and allows for a diverse set of applications and measurement techniques for remote sensing applications. It is quite remarkable that the sub-centimeter positioning precision and sub-nanosecond timing precision required to make this work properly can in fact be achieved under such real-world, often turbulent, vibrationally intensive conditions. Although the basic principles behind SAR imaging and interferometry have been known for decades, in recent years an explosion of data exploitation techniques enabled by ever-faster computational horsepower have enabled some remarkable advances. Although SAR images are often viewed as simple intensity maps of ground reflectivity, SAR is also an exquisitely sensitive coherent imaging modality with a wealth of information buried within the phase information in the image. Some of the examples featured in this presentation will include: (1) Interferometric SAR, where by comparing the difference in phase between two SAR images one can measure subtle changes in ground topography at the wavelength scale. (2) Change detection, in which carefully geolocated images formed from two different passes are compared. (3) Multi-pass 3D SAR tomography, where multiple trajectories can be used to form 3D images. (4) Moving Target Indication (MTI), in which Doppler effects allow one to detect and

  13. Vertical Velocity Retrievals using the ARM Heterogeneous Radar Network at SGP

    NASA Astrophysics Data System (ADS)

    North, Kirk; Collis, Scott; Kollias, Pavlos

    2013-04-01

    The representation of convective clouds in numerical models underlines one of the most challenging problems to date faced by the modeling community. Since the dynamical, thermodynamical, and microphysical processes of convective systems occur at spatial and temporal scales not resolved by large-scale models, parameterization schemes must be implemented in order to represent these processes. A key component in these parameterizations is vertical velocity, since many of these schemes rely on mass-flux closure: a model grid cell is decomposed into an updraft region within the cloud layer, compensated by both a downdraft which is part of the convective system as well as slow subsidence of the environment. Despite this, observations of vertical velocity are sparse, either from aircraft studies or vertically-pointing radars, both of which cover a limited area. As a result, evaluation of large-scale models is primarily done with other, small-scale models, not observations. Scanning Doppler radars, though unable to directly measure vertical velocity, are able to observe mesoscale convective systems at high spatial resolution. Utilizing the unprecedented observing infrastructure at ARM's Southern Great Plains (SGP) site, we retrieve vertical velocity from multiple Doppler radars using a 3D-VAR technique. Multiple convective events observed during the Midlatitude Continental Convective Clouds Experiment (MC3E) provides an appropriate dataset to study the statistical properties of vertical velocity as well as draft morphology in convective clouds. Furthermore, these retrievals are evaluated by comparing them with independent vertical velocity retrievals from vertically-pointing UHF radars.

  14. Space Radar Image of St. Louis, Missouri

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a spaceborne radar image of the area surrounding St. Louis, Missouri, where the Mississippi and Missouri Rivers come together. The city of St. Louis is the bright gold area within a bend in the Mississippi River at the lower center of the image. The rivers show up as dark blue sinuous lines. Urbanized areas appear bright gold and forested areas are shown as a brownish color. Several bridges can be seen spanning the river near downtown St. Louis. The Missouri River flows east, from left to right, across the center of the image, and meets the Mississippi River, which flows from top to bottom of the image. A small stretch of the Illinois River is shown at the top of the image where it merges with the Mississippi. The Mississippi forms the state boundary between Illinois (to the right) and Missouri (to the left). Flat farmland areas within the river floodplains appear blue on the image. The major roadways that pass through the area can be seen radiating out from, and encircling, the city of St. Louis. These highways, the rivers and the bridges help maintain St. Louis' reputation as the 'Gateway to the West.

  15. Directional ocean wave measurements in a coastal setting using a focused array imaging radar

    SciTech Connect

    Frasier, S.J.; Liu, Y.; Moller, D.; McIntosh, R.E.; Long, C.

    1995-03-01

    A unique focused array imaging Doppler radar was used to measure directional spectra of ocean surface waves in a nearshore experiment performed on the North Carolina Outer Banks. Radar images of the ocean surface`s Doppler velocity were used to generate two dimensional spectra of the radial component of the ocean surface velocity field. These are compared to simultaneous in-situ measurements made by a nearby array of submerged pressure sensors. Analysis of the resulting two-dimensional spectra include comparisons of dominant wave lengths, wave directions, and wave energy accounting for relative differences in water depth at the measurement locations. Limited estimates of the two-dimensional surface displacement spectrum are derived from the radar data. The radar measurements are analogous to those of interferometric synthetic aperture radars (INSAR), and the equivalent INSAR parameters are shown. The agreement between the remote and in-situ measurements suggests that an imaging Doppler radar is effective for these wave measurements at near grazing incidence angles.

  16. Advanced Research into Moving Target Imaging Using Multistatic Radar

    DTIC Science & Technology

    2009-12-01

    From [2])...........................................................................................................5 Figure 6. SAR and ISAR schemes...SAR and ISAR schemes for imaging targets (From [2]) Synthetic aperture imaging can be accomplished using a stationary antenna and rotating target or a...with a series of pulses from the moving antenna (Figure 6). Inverse synthetic aperture radar ( ISAR ) assumes a stationary radar radiating a moving

  17. Automatic position calculating imaging radar with low-cost synthetic aperture sensor for imaging layered media

    DOEpatents

    Mast, Jeffrey E.

    1998-01-01

    An imaging system for analyzing structures comprises a radar transmitter and receiver connected to a timing mechanism that allows a radar echo sample to be taken at a variety of delay times for each radar pulse transmission. The radar transmitter and receiver are coupled to a position determining system that provides the x,y position on a surface for each group of samples measured for a volume from the surface. The radar transmitter and receiver are moved about the surface to collect such groups of measurements from a variety of x,y positions. Return signal amplitudes represent the relative reflectivity of objects within the volume and the delay in receiving each signal echo represents the depth at which the object lays in the volume and the propagation speeds of the intervening material layers. Successively deeper z-planes are backward propagated from one layer to the next with an adjustment for variations in the expected propagation velocities of the material layers that lie between adjacent z-planes.

  18. Automatic position calculating imaging radar with low-cost synthetic aperture sensor for imaging layered media

    DOEpatents

    Mast, J.E.

    1998-08-18

    An imaging system for analyzing structures comprises a radar transmitter and receiver connected to a timing mechanism that allows a radar echo sample to be taken at a variety of delay times for each radar pulse transmission. The radar transmitter and receiver are coupled to a position determining system that provides the x,y position on a surface for each group of samples measured for a volume from the surface. The radar transmitter and receiver are moved about the surface to collect such groups of measurements from a variety of x,y positions. Return signal amplitudes represent the relative reflectivity of objects within the volume and the delay in receiving each signal echo represents the depth at which the object lays in the volume and the propagation speeds of the intervening material layers. Successively deeper z-planes are backward propagated from one layer to the next with an adjustment for variations in the expected propagation velocities of the material layers that lie between adjacent z-planes. 10 figs.

  19. Space Radar Image of Mammoth, California

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This image is a false-color composite of the Mammoth Mountain area in the Sierra Nevada Mountains, California. The image is centered at 37.6 degrees north latitude and 119.0 degrees west longitude. The area is approximately 11.5 kilometers by 78.3 kilometers (7.2 by 48.7 miles) in size. The image was acquired by the Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) aboard space shuttle Endeavour on its 40th orbit, April 11, 1994. The city of Mammoth Lakes is visible in the bottom right portion of the scene. In this color representation, red is C-band HV-polarization, green is C-band VV-polarization and blue is the ratio of C-band VV to C-band HV. Blue areas are lakes or slopes facing away from the radar illumination. Yellow represents areas of dry, old snow as well as slopes facing directly the radar illumination. At the time of the SIR-C overflight, the sky conditions were partially cloudy, with low and cold air temperatures. Total snow depth is about 1 to 1.5 meters (3 to 5 feet). The current snow accumulation is only about 40 percent of the average for the season. The most recent snowfall in the area covered the entire area with about 30 centimeters (14 inches) of fresh dry snow. Above 3,000 meters (10,000 feet) elevation the snowpack is dry. Below that elevation, the snowpack has a layered structure. Snow hydrologists are using SIR-C/X-SAR data to determine both the quantity of water held by seasonal snowpack and the amount of snow melting. SIR-C/X-SAR radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm)and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, in conjunction with aircraft and ground studies, will give scientists clearer insights into those

  20. Space Radar Image of Weddell Sea, Antarctica

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar color composite shows a portion of the Weddell Sea, which is adjacent to the continent of Antarctica. The image shows extensive coverage of first-year sea ice mixtures and patches of open water inside the ice margin. The image covers a 100 kilometer by 30 kilometer (62 mile by 18.5 mile) region of the southern ocean, centered at approximately 57 degrees south latitude and 3 degrees east longitude, which was acquired on October 3, 1994. Data used to create this image were obtained using the L-band (horizontally transmitted and vertically received) in red; the L-band (horizontally transmitted and received) in green; and the C-band (horizontally transmitted and received) in blue. The sea ice, which appears rust-brown in the image, is composed of loosely packed floes from approximately 1 meter to 2 meters (3 feet to 6.5 feet) thick and ranging from 1 meter to 20 meters (3 feet to 65.5 feet) in diameter. Large patches of open water, shown as turquoise blue, are scattered throughout the area, which is typical for ice margins experiencing off-ice winds. The thin, well-organized lines clearly visible in the ice pack are caused by radar energy reflected by floes riding the crest of ocean swells. The wispy, black features seen throughout the image represent areas where new ice is forming. Sea ice, because it acts as an insulator, reduces the loss of heat between the relatively warm ocean and cold atmosphere. This interaction is an important component of the global climate system. Because of the unique combination of winds, currents and temperatures found in this region, ice can extend many hundreds of kilometers north of Antarctica each winter, which classifies the Weddell Sea as one of nature's greatest ice-making engines. During the formation of sea ice, great quantities of salt are expelled from the frozen water. The salt increases the density of the upper layer of sea water, which then sinks to great depths

  1. Mixed-phase cloud phase partitioning using millimeter wavelength cloud radar Doppler velocity spectra

    NASA Astrophysics Data System (ADS)

    Yu, G.; Verlinde, J.; Clothiaux, E. E.; Chen, Y.-S.

    2014-06-01

    Retrieving and quantifying cloud liquid drop contributions to radar returns from mixed-phase clouds remains a challenge because the radar signal is frequently dominated by the returns from the ice particles within the radar sample volume. We present a technique that extracts the weak cloud liquid drop contributions from the total radar returns in profiling cloud radar Doppler velocity spectra. Individual spectra are first decomposed using a continuous wavelet transform, the resulting coefficients of which are used to identify the region in the spectra where cloud liquid drops contribute. By assuming that the liquid contribution to each Doppler spectrum is Gaussian shaped and centered on an appropriate peak in the wavelet coefficients, the cloud liquid drop contribution may be estimated by fitting a Gaussian distribution centered on the velocity of this peak to the original Doppler spectrum. The cloud liquid drop contribution to reflectivity, the volume mean vertical air motion, subvolume vertical velocity variance, and ice particle mean fall speed can be estimated based on the separation of the liquid contribution to the radar Doppler spectrum. The algorithm is evaluated using synthetic spectra produced from output of a state-of-the-art large eddy simulation model study of an Arctic mixed-phase cloud. The retrievals of cloud liquid drop mode reflectivities were generally consistent with the original model values with errors less than a factor of 2. The retrieved volume mean vertical air velocities reproduced the updraft and downdraft structures, but with an overall bias of approximately -0.06 m s-1. Retrievals based on Ka-band Atmospheric Radiation Measurement Program Zenith Radar observations from Barrow, Alaska, during October 2011 are also presented.

  2. Measuring melt and velocity of Alaskan mountain glaciers using phase-sensitive radar and differential GPS

    NASA Astrophysics Data System (ADS)

    Neuhaus, S.; Tulaczyk, S. M.

    2015-12-01

    Alaskan glaciers show some of the highest rates of retreat worldwide, contributing to sea level rise. This retreat is due to both increased velocity and increased melt. We seek to understand the role of glacial meltwater on velocity. Matanuska glacier, a land terminating glacier in Alaska, has been well-studied using traditional glaciological techniques, but new technology has emerged that allows us to measure melt and velocity more accurately. We employed high-resolution differential GPS to create surface velocity profiles across flow in the ablation zone during the summer of 2015. We also measured surface ablation using stakes and measured basal melt using phase-sensitive radar designed by the British Antarctic Survey. The positions acquired by differential GPS are obtained to a resolution of less than 0.5m, while feature tracking using time-lapse photography for the same time period yields positions with greater and more variable uncertainty. The phase-sensitive radar provides ice thinning rates. Phase-sensitive radar together with ground penetrating radar provides us with an understanding of the internal structure of the glacier. This suite of data allows us to determine the relative importance of surface melt, basal melt, and internal deformation on ice velocity in warm mountain glaciers.

  3. Spaceborne radar observations: A guide for Magellan radar-image analysis

    NASA Technical Reports Server (NTRS)

    Ford, J. P.; Blom, R. G.; Crisp, J. A.; Elachi, Charles; Farr, T. G.; Saunders, R. Stephen; Theilig, E. E.; Wall, S. D.; Yewell, S. B.

    1989-01-01

    Geologic analyses of spaceborne radar images of Earth are reviewed and summarized with respect to detecting, mapping, and interpreting impact craters, volcanic landforms, eolian and subsurface features, and tectonic landforms. Interpretations are illustrated mostly with Seasat synthetic aperture radar and shuttle-imaging-radar images. Analogies are drawn for the potential interpretation of radar images of Venus, with emphasis on the effects of variation in Magellan look angle with Venusian latitude. In each landform category, differences in feature perception and interpretive capability are related to variations in imaging geometry, spatial resolution, and wavelength of the imaging radar systems. Impact craters and other radially symmetrical features may show apparent bilateral symmetry parallel to the illumination vector at low look angles. The styles of eruption and the emplacement of major and minor volcanic constructs can be interpreted from morphological features observed in images. Radar responses that are governed by small-scale surface roughness may serve to distinguish flow types, but do not provide unambiguous information. Imaging of sand dunes is rigorously constrained by specific angular relations between the illumination vector and the orientation and angle of repose of the dune faces, but is independent of radar wavelength. With a single look angle, conditions that enable shallow subsurface imaging to occur do not provide the information necessary to determine whether the radar has recorded surface or subsurface features. The topographic linearity of many tectonic landforms is enhanced on images at regional and local scales, but the detection of structural detail is a strong function of illumination direction. Nontopographic tectonic lineaments may appear in response to contrasts in small-surface roughness or dielectric constant. The breakpoint for rough surfaces will vary by about 25 percent through the Magellan viewing geometries from low to high

  4. Non-Cooperative Target Imaging and Parameter Estimation with Narrowband Radar Echoes

    PubMed Central

    Yeh, Chun-mao; Zhou, Wei; Lu, Yao-bing; Yang, Jian

    2016-01-01

    This study focuses on the rotating target imaging and parameter estimation with narrowband radar echoes, which is essential for radar target recognition. First, a two-dimensional (2D) imaging model with narrowband echoes is established in this paper, and two images of the target are formed on the velocity-acceleration plane at two neighboring coherent processing intervals (CPIs). Then, the rotating velocity (RV) is proposed to be estimated by utilizing the relationship between the positions of the scattering centers among two images. Finally, the target image is rescaled to the range-cross-range plane with the estimated rotational parameter. The validity of the proposed approach is confirmed using numerical simulations. PMID:26805836

  5. Space Radar Image of Mammoth Mountain, California

    NASA Technical Reports Server (NTRS)

    1994-01-01

    These two false-color composite images of the Mammoth Mountain area in the Sierra Nevada Mountains, Calif., show significant seasonal changes in snow cover. The image at left was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar aboard the space shuttle Endeavour on its 67th orbit on April 13, 1994. The image is centered at 37.6 degrees north latitude and 119 degrees west longitude. The area is about 36 kilometers by 48 kilometers (22 miles by 29 miles). In this image, red is L-band (horizontally transmitted and vertically received) polarization data; green is C-band (horizontally transmitted and vertically received) polarization data; and blue is C-band (horizontally transmitted and received) polarization data. The image at right was acquired on October 3, 1994, on the space shuttle Endeavour's 67th orbit of the second radar mission. Crowley Lake appears dark at the center left of the image, just above or south of Long Valley. The Mammoth Mountain ski area is visible at the top right of the scene. The red areas correspond to forests, the dark blue areas are bare surfaces and the green areas are short vegetation, mainly brush. The changes in color tone at the higher elevations (e.g. the Mammoth Mountain ski area) from green-blue in April to purple in September reflect changes in snow cover between the two missions. The April mission occurred immediately following a moderate snow storm. During the mission the snow evolved from a dry, fine-grained snowpack with few distinct layers to a wet, coarse-grained pack with multiple ice inclusions. Since that mission, all snow in the area has melted except for small glaciers and permanent snowfields on the Silver Divide and near the headwaters of Rock Creek. On October 3, 1994, only discontinuous patches of snow cover were present at very high elevations following the first snow storm of the season on September 28, 1994. For investigations in hydrology and land-surface climatology, seasonal snow

  6. Antarctica: measuring glacier velocity from satellite images

    SciTech Connect

    Lucchitta, B.K.; Ferguson, H.M.

    1986-11-28

    Many Landsat images of Antarctica show distinctive flow and crevasse features in the floating part of ice streams and outlet glaciers immediately below their grounding zones. Some of the features, which move with the glacier or ice stream, remain visible over many years and thus allow time-lapse measurements of ice velocities. Measurements taken from Landsat images of features on Byrd Glacier agree well with detailed ground and aerial observations. The satellite-image technique thus offers a rapid and cost-effective method of obtaining average velocities, to a first order of accuracy, of many ice streams and outlet glaciers near their termini.

  7. Space Radar Image of Death Valley, California

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This image shows Death Valley, California, centered at 36.629 degrees north latitude, 117.069 degrees west longitude. The image shows Furnace Creek alluvial fan and Furnace Creek Ranch at the far right, and the sand dunes near Stove Pipe Wells at the center. The dark fork-shaped feature between Furnace Creek fan and the dunes is a smooth flood-plain which encloses Cottonball Basin. This SIR-C/X-SAR supersite is an area of extensive field investigations and has been visited by both Space Radar Lab astronaut crews. Elevations in the valley range from 70 meters (230 feet) below sea level, the lowest in the United States, to more than 3,300 meters (10,800 feet) above sea level. Scientists are using SIR-C/X-SAR data from Death Valley to help answer a number of different questions about Earth's geology. One question concerns how alluvial fans are formed and change through time under the influence of climatic changes and earthquakes. Alluvial fans are gravel deposits that wash down from the mountains over time. They are visible in the image as circular, fan-shaped bright areas extending into the darker valley floor from the mountains. Information about the alluvial fans helps scientists study Earth's ancient climate. Scientists know the fans are built up through climatic and tectonic processes and they will use the SIR-C/X-SAR data to understand the nature and rates of weathering processes on the fans, soil formation and the transport of sand and dust by the wind. SIR-C/X-SAR's sensitivity to centimeter-scale (inch-scale) roughness provides detailed maps of surface texture. Such information can be used to study the occurrence and movement of dust storms and sand dunes. The goal of these studies is to gain a better understanding of the record of past climatic changes and the effects of those changes on a sensitive environment. This may lead to a better ability to predict future response of the land to different potential global climate-change scenarios. Death Valley is

  8. On the focusing issue of synthetic aperture radar imaging of ocean waves

    SciTech Connect

    Bruning, C. ); Alpers, W.R. ); Schroter, J.G. )

    1991-01-01

    It is now widely accepted that the imaging of ocean surface waves by synthetic aperture radar (SAR) can be adequately described by velocity bunching theory in conjunction with the two-scale wave model. However, it has been conjectured that this theory is incapable of explaining why, under certain conditions, the image contrast of airborne SAR imagery of ocean waves can be enhanced by defocusing the SAR processor. It this were true it would raise serious doubts about the validity of the velocity bunching theory to describe the SAR imaging of ocean waves. In this paper the velocity bunching theory is defended. It is shown that image contrast enhancement by defocusing can also be obtained by this theory, which does not require the introduction of the phase or group velocity of the long ocean waves as a basic element of the SAR imaging theory.

  9. Spaceborne synthetic-aperture imaging radars - Applications, techniques, and technology

    NASA Technical Reports Server (NTRS)

    Elachi, C.; Bicknell, T.; Jordan, R. L.; Wu, C.

    1982-01-01

    In June 1978, the Seasat satellite was placed into orbit around the earth with a synthetic-aperture imaging radar (SAR) as one of the payload sensors. The Seasat SAR provided, for the first time, synoptic radar images of the earth's surface with a resolution of 25 m. In November 1981, the second imaging radar was successfully operated from space on the Shuttle. The Shuttle Imaging Radar-A acquired images over a variety of regions around the world with an imaging geometry different from the one used by the Seasat SAR. The spaceborne SAR principle is discussed, taking into account ambiguities, orbital and environmental factors, range curvature and range walk, surface interaction mechanisms, thermal and speckle noise, key tradeoff parameters, and nonconventional SAR systems. Attention is also given to spaceborne SAR sensors, the digital processing of spaceborne SAR data, the optical processing of spaceborne SAR data, postimage formation processing, data interpretation techniques and applications, and the next decade.

  10. Use of radar image texture in geologic mapping

    NASA Technical Reports Server (NTRS)

    Farr, T. G.

    1983-01-01

    Large slope angle radar and small slope angle radar techniques are discussed. The techniques are developed to aid in the geologic interpretation of synthetic aperture radar (SAR) images. The application presented is for heavy vegetation and where very little other data can be obtained directly from remote sensing images. To understand the relationships between image texture, topography, lithology, geomorphology, and climate improves, textural information from SAR images are used for the identification of rock types to discriminate units. An active program is to integrate textural information from radar images directly with backscatter data from the same images, and with compositional information derived from visible near infrared sensors such as LANDSAT is explored. The role of quantitative textural information in this type of multisensor analysis which promises to be significant is outlined.

  11. Ground Penetrating Radar Imaging of Tephra Fallout and Surge Deposits

    NASA Astrophysics Data System (ADS)

    Kruse, S.; Martin, K.; Connor, C.; Mora, R.; Ramirez, C.; Alvarado, G.

    2005-05-01

    GPR profiles on Cerro Negro volcano, Nicaragua, and Poás, Irazú, and Arenal volcanoes, Costa Rica, show this method has utility for mapping tephra blanket and surge deposit thicknesses, as well as ballistics distributions. These data are useful for estimating eruption volumes, particularly close to vents where deposits may be thicker than trenching depths. In the dry, highly resistive tephra of the Cerro Negro basaltic cinder cone, distinct deposits are clearly imaged between 2 and 20 m depth. The lowermost coherent reflection is presumed to be the contact with underlying pre-Cerro Negro lavas and weathered tephra deposits. Within the 2-20 m package, individual reflecting horizons are clearly resolved, and reflection attributes, particularly phase, may contain useful information on the nature of contacts, such as abrupt changes in granulometry. Because of the very high velocities at Cerro Negro (0.14 m/ns), even with 200 MHz antennas strata shallower than 2 m are difficult to resolve. In contrast, wetter ash, pumice, paleosol, and surge deposits on Irazú and Poás volcanoes show velocities as low as 0.045 m/ns. The corresponding shorter wavelengths permit strata as shallow as 40-70 cm to be imaged with 200 MHz antennas, with depth penetration typically 5 to 8 m. Comparison of trench observations and radar profiles indicates that strong radar reflections are produced by iron-rich zones at the water table and soil-ash contacts. Other features visible in the profiles are small (tens of cm) sub-vertical offsets of nearly horizontal units, and diffractions or disruptions in horizontal units presumed to reflect >30 cm blocks.

  12. Ultrawideband radar imaging system for biomedical applications

    SciTech Connect

    Jafari, H.M.; Liu, W.; Hranilovic, S.; Deen, M.J.

    2006-05-15

    Ultrawideband (UWB) (3-10 GHz) radar imaging systems offer much promise for biomedical applications such as cancer detection because of their good penetration and resolution characteristics. The underlying principle of UWB cancer detection is a significant contrast in dielectric properties, which is estimated to be greater than 2:1 between normal and cancerous tissue, compared to a few-percent contrast in radiographic density exploited by x rays. This article presents a feasibility study of the UWB imaging of liver cancer tumors, based on the frequency-dependent finite difference time domain method. The reflection, radiation, and scattering properties of UWB pulses as they propagate through the human body are studied. The reflected and back-scattered electromagnetic energies from cancer tumors inside the liver are also investigated. An optimized, ultrawideband antenna was designed for near field operation, allowing for the reduction of the air-skin interface. It will be placed on the fat-liver tissue phantom with a malignant tumor stimulant. By performing an incremental scan over the phantom and removing early time artifacts, including reflection from the antenna ends, images based on the back-scattered signal from the tumor can be constructed. This research is part of our effort to develop a UWB cancer detection system with good detection and localization properties.

  13. Multifrequency and multipolarization radar scatterometry of sand dunes and comparison with spaceborne and airborne radar images

    NASA Technical Reports Server (NTRS)

    Blom, Ronald; Elachi, Charles

    1987-01-01

    Airborne radar scatterometer data on sand dunes, acquired at multiple frequencies and polarizations, are reported. Radar backscatter from sand dunes is very sensitive to the imaging geometry. At small incidence angles the radar return is mainly due to quasi-specular reflection from dune slopes favorably oriented toward the radar. A peak return usually occurs at the incidence angle equal to the angle of repose for the dunes. The peak angle is the same at all frequencies as computed from specular reflection theory. At larger angles the return is significantly weaker. The scatterometer measurements verified observations made with airborne and spaceborne radar images acquired over a number of dune fields in the U.S., central Africa, and the Arabian peninsula. The imaging geometry constraints indicate that possible dunes on other planets, such as Venus, will probably not be detected in radar images unless the incidence angle is less than the angles of repose of such dunes and the radar look direction is approximately orthogonal to the dune trends.

  14. Theory of Digital Imaging from Orbital Synthetic Aperture Radar

    DTIC Science & Technology

    1983-11-01

    FROM ORBITAL SYNTHETIC APERTURE RADAR O by B. C. Barber SUMMARY Digital synthetic aperture radar ( SAR ) imaging techniques have pre- viously only been...reported in the literature in a fragmentary manner. This article presents a comprehensive review of the theory of digital SAR imaging from Earth...orbiting satellites. The digital SAR imaging process is explained, including a discussion of various aspects which are specific to satellite-borne SAR . A

  15. Imaging Radar Applications in the Death Valley Region

    NASA Technical Reports Server (NTRS)

    Farr, Tom G.

    1996-01-01

    Death Valley has had a long history as a testbed for remote sensing techniques (Gillespie, this conference). Along with visible-near infrared and thermal IR sensors, imaging radars have flown and orbited over the valley since the 1970's, yielding new insights into the geologic applications of that technology. More recently, radar interferometry has been used to derive digital topographic maps of the area, supplementing the USGS 7.5' digital quadrangles currently available for nearly the entire area. As for their shorter-wavelength brethren, imaging radars were tested early in their civilian history in Death Valley because it has a variety of surface types in a small area without the confounding effects of vegetation. In one of the classic references of these early radar studies, in a semi-quantitative way the response of an imaging radar to surface roughness near the radar wavelength, which typically ranges from about 1 cm to 1 m was explained. This laid the groundwork for applications of airborne and spaceborne radars to geologic problems in and regions. Radar's main advantages over other sensors stems from its active nature- supplying its own illumination makes it independent of solar illumination and it can also control the imaging geometry more accurately. Finally, its long wavelength allows it to peer through clouds, eliminating some of the problems of optical sensors, especially in perennially cloudy and polar areas.

  16. Submillimeter-wavelength space-based imaging radar. Interim report

    SciTech Connect

    Manheimer, W.M.

    1988-05-31

    This report considers the use of a submillimeter wavelength space-based imaging radar. The main application envisioned is midcourse decoy discrimination for strategic defense, for which it would have the capability of producing a series of images, in real time, at strategic ranges, with less than meter-scale resolution and with modest power requirements. Undoubtedly, there are other applications. The requirements for a SAR and ISAR imaging radar at submillimeter wavelength are determined, and the prospect for the development of rf sources to power the radar is examined.

  17. Proceedings of the Third Spaceborne Imaging Radar Symposium

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This publication contains summaries of the papers presented at the Third Spaceborne Imaging Radar Symposium held at the Jet Propulsion Laboratory (JPL), California Institute of Technology, in Pasadena, California, on 18-21 Jan. 1993. The purpose of the symposium was to present an overview of recent developments in the different scientific and technological fields related to spaceborne imaging radars and to present future international plans. This symposium is the third in a series of 'Spaceborne Imaging Radar' symposia held at JPL. The first symposium was held in Jan. 1983 and the second in 1986.

  18. A comparison of vertical velocity variance measurements from wind profiling radars and sonic anemometers

    NASA Astrophysics Data System (ADS)

    McCaffrey, Katherine; Bianco, Laura; Johnston, Paul; Wilczak, James M.

    2017-03-01

    Observations of turbulence in the planetary boundary layer are critical for developing and evaluating boundary layer parameterizations in mesoscale numerical weather prediction models. These observations, however, are expensive and rarely profile the entire boundary layer. Using optimized configurations for 449 and 915 MHz wind profiling radars during the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA), improvements have been made to the historical methods of measuring vertical velocity variance through the time series of vertical velocity, as well as the Doppler spectral width. Using six heights of sonic anemometers mounted on a 300 m tower, correlations of up to R2 = 0. 74 are seen in measurements of the large-scale variances from the radar time series and R2 = 0. 79 in measurements of small-scale variance from radar spectral widths. The total variance, measured as the sum of the small and large scales, agrees well with sonic anemometers, with R2 = 0. 79. Correlation is higher in daytime convective boundary layers than nighttime stable conditions when turbulence levels are smaller. With the good agreement with the in situ measurements, highly resolved profiles up to 2 km can be accurately observed from the 449 MHz radar and 1 km from the 915 MHz radar. This optimized configuration will provide unique observations for the verification and improvement to boundary layer parameterizations in mesoscale models.

  19. High-resolution three-dimensional imaging radar

    NASA Technical Reports Server (NTRS)

    Cooper, Ken B. (Inventor); Chattopadhyay, Goutam (Inventor); Siegel, Peter H. (Inventor); Dengler, Robert J. (Inventor); Schlecht, Erich T. (Inventor); Mehdi, Imran (Inventor); Skalare, Anders J. (Inventor)

    2010-01-01

    A three-dimensional imaging radar operating at high frequency e.g., 670 GHz, is disclosed. The active target illumination inherent in radar solves the problem of low signal power and narrow-band detection by using submillimeter heterodyne mixer receivers. A submillimeter imaging radar may use low phase-noise synthesizers and a fast chirper to generate a frequency-modulated continuous-wave (FMCW) waveform. Three-dimensional images are generated through range information derived for each pixel scanned over a target. A peak finding algorithm may be used in processing for each pixel to differentiate material layers of the target. Improved focusing is achieved through a compensation signal sampled from a point source calibration target and applied to received signals from active targets prior to FFT-based range compression to extract and display high-resolution target images. Such an imaging radar has particular application in detecting concealed weapons or contraband.

  20. Flight simulator with IR and MMW radar image generation capabilities

    NASA Astrophysics Data System (ADS)

    Bonjean, Maxime E.; Lapierre, Fabian D.; Schiefele, Jens; Verly, Jacques G.

    2006-05-01

    In the future, modern airliners will use enhanced-synthesic vision systems (ESVS) to improve aeronautical operations in bad weather conditions. Before ESVS are effectively found aboard airliners, one must develop a multisensor flight simulator capable of synthetizing, in real time, images corresponding to a variety of imaging modalities. We present a real-time simulator called ARIS (Airborne Radar and Infrared Simulator) which is capable of generating two such imaging modalities: a forward-looking infrared (FLIR) and a millimeter-wave radar (MMWR) imaging system. The proposed simulator is modular sothat additional imaging modalities can be added. Example of images generated by the simulator are shown.

  1. A SEASAT-A synthetic aperture imaging radar system

    NASA Technical Reports Server (NTRS)

    Jordan, R. L.; Rodgers, D. H.

    1975-01-01

    The SEASAT, a synthetic aperture imaging radar system is the first radar system of its kind designed for the study of ocean wave patterns from orbit. The basic requirement of this system is to generate continuous radar imagery with a 100 km swath with 25m resolution from an orbital altitude of 800 km. These requirements impose unique system design problems. The end to end data system described including interactions of the spacecraft, antenna, sensor, telemetry link, and data processor. The synthetic aperture radar system generates a large quantity of data requiring the use of an analog link with stable local oscillator encoding. The problems associated in telemetering the radar information with sufficient fidelity to synthesize an image on the ground is described as well as the selected solutions to the problems.

  2. The JPL imaging radar experiment in GATE: A preliminary report

    NASA Technical Reports Server (NTRS)

    Elachi, C.

    1975-01-01

    The type of data that was taken with the JPL imaging radar during the Global Atmospheric Research Program (GARP) Atlantic Tropical Experiment (GATE) mission is summarized. A representative sample of the data is given.

  3. Beam Width Robustness of a 670 GHz Imaging Radar

    NASA Technical Reports Server (NTRS)

    Cooper, K. B.; Llombart, N.; Dengler, R. J.; Siegel, P. H.

    2009-01-01

    Detection of a replica bomb belt concealed on a mannequin at 4 m standoff range is achieved using a 670 GHz imaging radar. At a somewhat larger standoff range of 4.6 m, the radar's beam width increases substantially, but the through-shirt image quality remains good. This suggests that a relatively modest increase in aperture size over the current design will be sufficient to detect person-borne concealed weapons at ranges exceeding 25 meters.

  4. A Robust Mine Detection Algorithm for Acoustic and Radar Images

    DTIC Science & Technology

    2000-10-01

    Hough transforms as demonstrated on an NVL mine hunting SBIR and on SAR ground target detection. The fundamental detection technique will be...Williams, “IA-CHAMELEON: A SAR Wide Area Image Analysis Aid,” Proc. ATRWG Workshop, Baltimore, MD, July 1996 The adaptive detection algorithm will...University, Mississippi 38677, September 15, 1998 Systems Incorporated (PSI) Ground Penetrating Radar (GPR)9, and on synthetic aperture radar ( SAR ) images

  5. Linear FMCW Laser Radar for Precision Range and Vector Velocity Measurements

    NASA Technical Reports Server (NTRS)

    Pierrottet, Diego; Amzajerdian, Farzin; Petway, Larry; Barnes, Bruce; Lockhard, George; Rubio, Manuel

    2008-01-01

    An all fiber linear frequency modulated continuous wave (FMCW) coherent laser radar system is under development with a goal to aide NASA s new Space Exploration initiative for manned and robotic missions to the Moon and Mars. By employing a combination of optical heterodyne and linear frequency modulation techniques and utilizing state-of-the-art fiber optic technologies, highly efficient, compact and reliable laser radar suitable for operation in a space environment is being developed. Linear FMCW lidar has the capability of high-resolution range measurements, and when configured into a multi-channel receiver system it has the capability of obtaining high precision horizontal and vertical velocity measurements. Precision range and vector velocity data are beneficial to navigating planetary landing pods to the preselected site and achieving autonomous, safe soft-landing. The all-fiber coherent laser radar has several important advantages over more conventional pulsed laser altimeters or range finders. One of the advantages of the coherent laser radar is its ability to measure directly the platform velocity by extracting the Doppler shift generated from the motion, as opposed to time of flight range finders where terrain features such as hills, cliffs, or slopes add error to the velocity measurement. Doppler measurements are about two orders of magnitude more accurate than the velocity estimates obtained by pulsed laser altimeters. In addition, most of the components of the device are efficient and reliable commercial off-the-shelf fiber optic telecommunication components. This paper discusses the design and performance of a second-generation brassboard system under development at NASA Langley Research Center as part of the Autonomous Landing and Hazard Avoidance (ALHAT) project.

  6. Imaging thermal ion mass and velocity analyzer

    NASA Astrophysics Data System (ADS)

    Yau, A. W.; King, E. P.; Amerl, P.; Berg, K.; Enno, G.; Howarth, A.; Wevers, I.; White, A.

    2013-11-01

    The aim of an imaging thermal ion mass and velocity analyzer is to apply imaging techniques to measure in-situ the mass composition and detailed velocity phase space distributions of a thermal plasma population in a planetary ionosphere or magnetosphere and use the measured distributions to derive the bulk plasma parameters and to detect the possible presence of non-thermal distributions. A hemispherical electrostatic analyzer (HEA) with a planar entrance aperture can sample simultaneously incident ions or electrons over an extended energy range and the full 360° range of incident azimuth, and disperse them by their energy-per-charge while retaining their incident azimuth, thus providing a means to image the 2-dimensional (2D) ion or electron energy-per-charge and angular (azimuth) distribution. Therefore an ion mass and velocity analyzer consisting of a HEA embedded with an ion-mass spectrometer is capable of imaging the 2-D detailed ion velocity distribution—and measuring the 3D distribution on a spinning spacecraft if the planar entrance aperture is aligned along the spacecraft spin axis. For 3D velocity distribution measurements on a 3-axis stabilized spacecraft, an analyzer with electrostatic deflection capability will be required to deflect ions at arbitrary incident elevation angles into the planar entrance aperture for sampling. An imaging thermal ion mass and velocity analyzer is presented that combines a HEA, a time-of-flight ion mass spectrometer, and a pair of electrostatic deflectors, and is capable of sampling low-energy ions (˜1 to 100 eV/e) of all mass species (1 to > 40 AMU/e) from all incident directions on a non-spinning platform, at up to (10% energy resolution (ΔE/E) and ˜5° angular resolution. Using the HEA to measure the energy-percharge of each detected ion and the time-of-flight gate to measure the transit time of the ion inside the analyzer, this instrument can resolve all major ion species in the ionosphere including H+, He+ and O

  7. Determination of U, V, and W from single station Doppler radar radial velocities

    NASA Technical Reports Server (NTRS)

    Clark, W. L.; Green, J. L.; Warnock, J. M.

    1986-01-01

    The ST/MST (stratosphere troposphere/mesosphere stratosphere troposphere) clear air Doppler radar, or wind profiler, is an important tool in observational meteorology because of its capability to remote observe dynamic parameters of the atmosphere. There are difficulties in transforming the observed radial velocities into meteorological wind components. How this problem has been treated in the past is reviewed, and some of the analysis is recast to a form more suited to the high diagnostic abilities of a number of fixed beam configurations with reference to a linear wind field. The results, in conjunction with other works which treats problems such as the effects of finite sample volumes in the presence of nonhomogeneous atmospheric reflectivity, have implications important to the design of both individual MST/ST radars and MST/ST radar networks. The key parameters to uncoupling terms in the scaling equations are w sub x and w sub y. Whenever the stratiform condition, which states that these two parameters are negligible, is satisfied, a five beam ST radar may determine unbiased values of u, v, and w for sample volumes directly above the radar. The divergence and partial deformation of the flow may also be determined. Three beam systems can determine w and w sub z, but are unable to obtain u and v wind components uncontaminated by vertical sheer terms, even when the stratiform condition is satisfied.

  8. Passive synthetic aperture hitchhiker imaging of ground moving targets--Part 1: image formation and velocity estimation.

    PubMed

    Wacks, Steven; Yazici, Birsen

    2014-06-01

    In the Part 1 of this two-part study, we present a method of imaging and velocity estimation of ground moving targets using passive synthetic aperture radar. Such a system uses a network of small, mobile receivers that collect scattered waves due to transmitters of opportunity, such as commercial television, radio, and cell phone towers. Therefore, passive imaging systems have significant cost, manufacturing, and stealth advantages over active systems. We describe a novel generalized Radon transform-type forward model and a corresponding filtered-backprojection-type image formation and velocity estimation method. We form a stack of position images over a range of hypothesized velocities, and show that the targets can be reconstructed at the correct position whenever the hypothesized velocity is equal to the true velocity of targets. We then use entropy to determine the most accurate velocity and image pair for each moving target. We present extensive numerical simulations to verify the reconstruction method. Our method does not require a priori knowledge of transmitter locations and transmitted waveforms. It can determine the location and velocity of multiple targets moving at different velocities. Furthermore, it can accommodate arbitrary imaging geometries. In Part 2, we present the resolution analysis and analysis of positioning errors in passive SAR images due to erroneous velocity estimation.

  9. An adaptive filter for smoothing noisy radar images

    NASA Technical Reports Server (NTRS)

    Frost, V. S.; Stiles, J. A.; Shanmugam, K. S.; Holtzman, J. C.; Smith, S. A.

    1981-01-01

    A spatial domain adaptive Wiener filter for smoothing radar images corrupted by multiplicative noise is presented. The filter is optimum in a minimum mean squared error sense, computationally efficient, and preserves edges in the image better than other filters. The proposed algorithm can also be used for processing optical images with illumination variations that have a multiplicative effect.

  10. Multispectral microwave imaging radar for remote sensing applications

    NASA Technical Reports Server (NTRS)

    Larson, R. W.; Rawson, R.; Ausherman, D.; Bryan, L.; Porcello, L.

    1974-01-01

    A multispectral airborne microwave radar imaging system, capable of obtaining four images simultaneously is described. The system has been successfully demonstrated in several experiments and one example of results obtained, fresh water ice, is given. Consideration of the digitization of the imagery is given and an image digitizing system described briefly. Preliminary results of digitization experiments are included.

  11. Improving tomographic estimates of subsurface electromagnetic wave velocity obtained from ground-penetrating radar data

    NASA Astrophysics Data System (ADS)

    Irving, James D.

    Crosshole ground-penetrating radar (GPR) travel-time tomography is a popular geophysical technique for characterization of the shallow subsurface in environmental applications. With this technique, a critical factor determining the resolution of the velocity images obtained is the angular ray coverage of the subsurface region between the boreholes; when travel-time data representing a narrow range of ray angles are used for the tomography reconstruction, the resulting images contain undesirable directional smearing. Here, I investigate the problem that, even when the crosshole GPR survey geometry offers the potential for high-resolution imaging due to wide angular ray coverage of the inter-borehole region, two significant issues are commonly encountered when attempting to take advantage of this coverage. First, travel times corresponding to high-angle ray paths are often extremely difficult to pick because of low signal-to-noise ratios in the data. Secondly, even when high-angle travel-time data can be reliably determined, they often appear to be incompatible with the lower-angle data available, and tend to cause strong numerical artifacts when included in inversions. To address the high-angle picking problem noted above, I develop a method for determining first-break times in crosshole GPR data using cross-correlations. High-quality reference waveforms for this technique are obtained from the data through the stacking of common-ray-angle gathers. To address the incompatibility issue with high-angle data, I first develop finite-difference time-domain (FDTD) numerical modeling codes that allow for the determination of realistic crosshole GPR antenna current distributions, and the modeling of transmitted and received waveforms in heterogeneous media. Using these codes, I then find that the high-angle incompatibility issue is likely the result of assuming that first-arriving energy always travels directly between the antenna centers; at high transmitter

  12. Evaluation of gridded scanning ARM cloud radar reflectivity observations and vertical doppler velocity retrievals

    NASA Astrophysics Data System (ADS)

    Lamer, K.; Tatarevic, A.; Jo, I.; Kollias, P.

    2014-04-01

    The scanning Atmospheric Radiation Measurement (ARM) cloud radars (SACRs) provide continuous atmospheric observations aspiring to capture the 3-D cloud-scale structure. Sampling clouds in 3-D is challenging due to their temporal-spatial scales, the need to sample the sky at high elevations and cloud radar limitations. Thus, a suggested scan strategy is to repetitively slice the atmosphere from horizon to horizon as clouds advect over the radar (Cross-Wind Range-Height Indicator - CW-RHI). Here, the processing and gridding of the SACR CW-RHI scans are presented. First, the SACR sample observations from the ARM Southern Great Plains and Cape Cod sites are post-processed (detection mask, gaseous attenuation correction, insect filtering and velocity de-aliasing). The resulting radial Doppler moment fields are then mapped to Cartesian coordinates with time as one of the dimensions. Next the Cartesian-gridded Doppler velocity fields are decomposed into the horizontal wind velocity contribution and the vertical Doppler velocity component. For validation purposes, all gridded and retrieved fields are compared to collocated zenith-pointing ARM cloud radar measurements. We consider that the SACR sensitivity loss with range, the cloud type observed and the research purpose should be considered in determining the gridded domain size. Our results also demonstrate that the gridded SACR observations resolve the main features of low and high stratiform clouds. It is established that the CW-RHI observations complemented with processing techniques could lead to robust 3-D cloud dynamical representations up to 25-30 degrees off zenith. The proposed gridded products are expected to advance our understanding of 3-D cloud morphology, dynamics and anisotropy and lead to more realistic 3-D radiative transfer calculations.

  13. Observations of seasonal and diurnal glacier velocities at Mount Rainier, Washington using terrestrial radar interferometry

    NASA Astrophysics Data System (ADS)

    Allstadt, K. E.; Shean, D. E.; Campbell, A.; Fahnestock, M.; Malone, S. D.

    2015-07-01

    We present spatially continuous velocity maps using repeat terrestrial radar interferometry (TRI) measurements to examine seasonal and diurnal dynamics of alpine glaciers at Mount Rainier, Washington. We show that the Nisqually and Emmons glaciers have small slope-parallel velocities near the summit (< 0.2 m day-1), high velocities over their upper and central regions (1.0-1.5 m day-1), and stagnant debris-covered regions near the terminus (< 0.05 m day-1). Velocity uncertainties are as low as ±0.02-0.08 m day-1. We document a large seasonal velocity decrease of 0.2-0.7 m day-1 (-25 to -50 %) from July to November for most of the Nisqually glacier, excluding the icefall, suggesting significant seasonal subglacial water storage under most of the glacier. We did not detect diurnal variability above the noise level. Preliminary 2-D ice flow modeling using TRI velocities suggests that sliding accounts for roughly 91 and 99 % of the July velocity field for the Emmons and Nisqually glaciers, respectively. We validate our observations against recent in situ velocity measurements and examine the long-term evolution of Nisqually glacier dynamics through comparisons with historical velocity data. This study shows that repeat TRI measurements with > 10 km range can be used to investigate spatial and temporal variability of alpine glacier dynamics over large areas, including hazardous and inaccessible areas.

  14. Earth-based Radar Observations of Mercury: Imaging Results with the Upgraded Arecibo Radar

    NASA Astrophysics Data System (ADS)

    Harmon, J.

    With the completion of the Arecibo upgrade in 1998 came the opportunity to do Mercury radar imaging of unprecedented quality. Among the early results with the upgraded S-band radar was the delay-Doppler imaging of the north polar ice features at 1.5-km resolution (Harmon et al., 2001). These images provided accurate mapping of the putative ice deposits within shaded crater floors as well as a precise determination of the pole position. They also produced the surprising discovery of ice features in small craters and at relatively low latitudes, which places important constraints on thermal models. We are also planning imaging observations of the south pole as it returns to view in 2004 and subsequent years. Besides polar studies, an important component of the Arecibo program is full-disk radar imaging around the entire planet, with a special emphasis on the hemisphere left unimaged by Mariner 10. For this purpose we are conducting a program of delay-Doppler observations using the long-code method (Harmon, 2002), which produces cleaner images than conventional delay-Doppler. Most striking are the depolarized images, which are found to be dominated by bright features associated with fresh crater ejecta. These images show some spectacular rayed craters in the Tycho class, as well as numerous bright, rayless features from smaller impacts. Also visible are some diffuse albedo features with no obvious impact association. Some of these high-albedo patches are found in smooth plains regions such as Tolstoy basin and Tir Planitia, which is the reverse of the mare-highland contrast seen in radar images of the Moon. In addition to the imaging results, we will briefly review the major findings from the pre-upgrade radar altimetry measurements.

  15. Mapping surface currents from HF radar radial velocity measurements using optimal interpolation

    NASA Astrophysics Data System (ADS)

    Kim, Sung Yong; Terrill, Eric J.; Cornuelle, Bruce D.

    2008-10-01

    An optimal interpolation (OI) method to compute surface vector current fields from radial velocity measurements derived from high-frequency (HF) radars is presented. The method assumes a smooth spatial covariance relationship between neighboring vector currents, in contrast to the more commonly used un-weighted least-squares fitting (UWLS) method, which assumes a constant vector velocity within a defined search radius. This OI method can directly compute any quantities linearly related to the radial velocities, such as vector currents and dynamic quantities (divergence and vorticity) as well as the uncertainties of those respective fields. The OI method is found to be more stable than the UWLS method and reduces spurious vector solutions near the baselines between HF radar installations. The OI method produces a covariance of the uncertainty of the estimated vector current fields. Three nondimensional uncertainty indices are introduced to characterize the uncertainty of the vector current at a point, representing an ellipse with directional characteristics. The vector current estimation using the OI method eliminates the need for multiple mapping steps and optimally fills intermittent coverage gaps. The effects of angular interpolation of radial velocities, a commonly used step in the preprocessing of radial velocity data prior to vector current computation in the UWLS method, are presented.

  16. Imaging thermal plasma mass and velocity analyzer

    NASA Astrophysics Data System (ADS)

    Yau, Andrew W.; Howarth, Andrew

    2016-07-01

    We present the design and principle of operation of the imaging ion mass and velocity analyzer on the Enhanced Polar Outflow Probe (e-POP), which measures low-energy (1-90 eV/e) ion mass composition (1-40 AMU/e) and velocity distributions using a hemispherical electrostatic analyzer (HEA), a time-of-flight (TOF) gate, and a pair of toroidal electrostatic deflectors (TED). The HEA and TOF gate measure the energy-per-charge and azimuth of each detected ion and the ion transit time inside the analyzer, respectively, providing the 2-D velocity distribution of each major ionospheric ion species and resolving the minor ion species under favorable conditions. The TED are in front of the TOF gate and optionally sample ions at different elevation angles up to ±60°, for measurement of 3-D velocity distribution. We present examples of observation data to illustrate the measurement capability of the analyzer, and show the occurrence of enhanced densities of heavy "minor" O++, N+, and molecular ions and intermittent, high-velocity (a few km/s) upward and downward flowing H+ ions in localized regions of the quiet time topside high-latitude ionosphere.

  17. Microseismic Velocity Imaging of the Fracturing Zone

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Chen, Y.

    2015-12-01

    Hydraulic fracturing of low permeability reservoirs can induce microseismic events during fracture development. For this reason, microseismic monitoring using sensors on surface or in borehole have been widely used to delineate fracture spatial distribution and to understand fracturing mechanisms. It is often the case that the stimulated reservoir volume (SRV) is determined solely based on microseismic locations. However, it is known that for some fracture development stage, long period long duration events, instead of microseismic events may be associated. In addition, because microseismic events are essentially weak and there exist different sources of noise during monitoring, some microseismic events could not be detected and thus located. Therefore the estimation of the SRV is biased if it is solely determined by microseismic locations. With the existence of fluids and fractures, the seismic velocity of reservoir layers will be decreased. Based on this fact, we have developed a near real time seismic velocity tomography method to characterize velocity changes associated with fracturing process. The method is based on double-difference seismic tomography algorithm to image the fracturing zone where microseismic events occur by using differential arrival times from microseismic event pairs. To take into account varying data distribution for different fracking stages, the method solves the velocity model in the wavelet domain so that different scales of model features can be obtained according to different data distribution. We have applied this real time tomography method to both acoustic emission data from lab experiment and microseismic data from a downhole microseismic monitoring project for shale gas hydraulic fracturing treatment. The tomography results from lab data clearly show the velocity changes associated with different rock fracturing stages. For the field data application, it shows that microseismic events are located in low velocity anomalies. By

  18. The Spaceborne Imaging Radar-C, X-Band Synthetic Aperture radar (SIR-C/X-SAR) Mission Overview

    NASA Technical Reports Server (NTRS)

    Evans, D. L.; Stofan, E. R.; Farr, T.; Plaut, J.; vanZyl, J.; Kobrick, M.; Holt, B.; Way, J. B.; Ottl, H.; Schmullius, C.; Nithack, J.; Calamia, M.

    1994-01-01

    The Spaceborne Imaging Radar-C, X-Band Synthetic Aperture Radar (SIR-C/X-SAR) was launched on space shuttle Endeavour at 7:05 AM EDT, Saturday, April 9, 1994. Soon after launch, the radars were activated and began around the clock operations which lasted for the next 10 days.

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

    PubMed

    Soumekh, M

    1992-01-01

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

  20. Radar speed gun true velocity measurements of sports-balls in flight: application to tennis

    NASA Astrophysics Data System (ADS)

    Robinson, Garry; Robinson, Ian

    2016-02-01

    Spectators of ball-games often seem to be fascinated by the speed of delivery of the ball. They appear to be less interested in or even oblivious to the mechanism and accuracy of the measurement or where in the flight path of the ball the measurement is actually made. Radar speed guns using the Doppler effect are often employed for such speed measurements. It is well known that such guns virtually always measure the line-of-sight or radial velocity of the ball and as such will return a reading less than or equal to the true speed of the ball. In this paper, using only basic physics principles we investigate such measurements, in particular those associated with the service stroke in tennis. For the service trajectories employed here, a single radar gun located in line with the centre-line of the court in fact under-estimates the speed of a wide serve by about 3.4% at the point of delivery, and by about 14.3% on impact with the court. However, we demonstrate that both the magnitude and direction of the true velocity of the ball throughout its entire flight path may be obtained, at least in principle, by the use of four suitably placed radar speed guns. These four guns must be able to measure the ‘range’ to the ball, enabling its position in flight to be determined, and three of them must be able to measure the radial velocity of the ball. Restrictions on the locations of the speed guns are discussed. Such restrictions are quite liberal, although there are certain configurations of the radar gun positions which cannot be used. Importantly, with the one proviso that no speed gun can be directly in the path of the ball (not only for the obvious reasons), we find that if the speed of the ball can be determined for one point in the trajectory, it can also be determined for all points. The accuracy of the range and radial velocity measurements required to give meaningful results for the true velocity are also briefly discussed. It is found that the accuracy required

  1. Space Radar of Image Aorounga Impact Crater, Chad

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The impact of an asteroid or comet several hundred million years ago left scars in the landscape that are still visible in this spaceborne radar image of an area in the Sahara Desert of northern Chad. The concentric ring structure is the Aorounga impact crater, with a diameter of about 17 kilometers (10.5 miles). The original crater was buried by sediments, which were then partially eroded to reveal the current ring-like appearance. The dark streaks are deposits of windblown sand that migrate along valleys cut by thousands of years of wind erosion. The dark band in the upper right of the image is a portion of a proposed second crater. Scientists are using radar images to investigate the possibility that Aorounga is one of a string of impact craters formed by multiple impacts. Radar imaging is a valuable tool for the study of desert regions because the radar waves can penetrate thin layers of dry sand to reveal details of geologic structure that are invisible to other sensors. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on April 18 and 19, 1994, onboard the space shuttle Endeavour. The area shown is 22 kilometers by 28 kilometers (14 miles by 17 miles) and is centered at 19.1 degrees north latitude, 19.3 degrees east longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontally transmitted and received; and blue is C-band, horizontally transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  2. Space Radar Image of West Texas - SAR scan

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This radar image of the Midland/Odessa region of West Texas, demonstrates an experimental technique, called ScanSAR, that allows scientists to rapidly image large areas of the Earth's surface. The large image covers an area 245 kilometers by 225 kilometers (152 miles by 139 miles). It was obtained by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) flying aboard the space shuttle Endeavour on October 5, 1994. The smaller inset image is a standard SIR-C image showing a portion of the same area, 100 kilometers by 57 kilometers (62 miles by 35 miles) and was taken during the first flight of SIR-C on April 14, 1994. The bright spots on the right side of the image are the cities of Odessa (left) and Midland (right), Texas. The Pecos River runs from the top center to the bottom center of the image. Along the left side of the image are, from top to bottom, parts of the Guadalupe, Davis and Santiago Mountains. North is toward the upper right. Unlike conventional radar imaging, in which a radar continuously illuminates a single ground swath as the space shuttle passes over the terrain, a Scansar radar illuminates several adjacent ground swaths almost simultaneously, by 'scanning' the radar beam across a large area in a rapid sequence. The adjacent swaths, typically about 50 km (31 miles) wide, are then merged during ground processing to produce a single large scene. Illumination for this L-band scene is from the top of the image. The beams were scanned from the top of the scene to the bottom, as the shuttle flew from left to right. This scene was acquired in about 30 seconds. A normal SIR-C image is acquired in about 13 seconds. The ScanSAR mode will likely be used on future radar sensors to construct regional and possibly global radar images and topographic maps. The ScanSAR processor is being designed for 1996 implementation at NASA's Alaska SAR Facility, located at the University of Alaska Fairbanks, and will produce digital images from the

  3. Enhanced Polarimetric Radar Imaging Using Cross-Channel Coupling Constraints

    DTIC Science & Technology

    2014-06-19

    classification. Overall, the jointly enhanced image channels displayed significantly better polarimet- ric preservation compared to the corresponding...Potter, E. Ertin, J. T. Parker , and M. Cetin, “Sparsity and compressed sensing in radar imaging,” Proceedings of the IEEE, vol. 98, no. 6, pp. 1006

  4. Space Radar Image of Giza Egypt - with enlargement

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This radar image shows the area west of the Nile River near Cairo, Egypt. The Nile River is the dark band along the right side of the image and it flows approximately due North from the bottom to the right. The boundary between dense urbanization and the desert can be clearly seen between the bright and dark areas in the center of the image. This boundary represents the approximate extent of yearly Nile flooding which played an important part in determining where people lived in ancient Egypt. This land usage pattern persists to this day. The pyramids at Giza appear as three bright triangles aligned with the image top just at the boundary of the urbanized area. They are also shown enlarged in the inset box in the top left of the image. The Great Pyramid of Khufu (Cheops in Greek) is the northern most of the three Giza pyramids. The side-looking radar illuminates the scene from the top, the two sides of the pyramids facing the radar reflect most of the energy back to the antenna and appear radar bright; the two sides away from the radar reflect less energy back and appear dark Two additional pyramids can be seen left of center in the lower portion of the image. The modern development in the desert on the left side of the image is the Sixth of October City, an area of factories and residences started by Anwar Sadat to relieve urban crowding. The image was taken on April 19, 1994 by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. The image is centered on latitude 29.72 degrees North latitude and 30.83 degrees East longitude. The area shown is approximately 20 kilometers by 30 kilometers. The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, horizontally received; green is C

  5. Observation of sea-ice dynamics using synthetic aperture radar images: Automated analysis

    NASA Technical Reports Server (NTRS)

    Vesecky, John F.; Samadani, Ramin; Smith, Martha P.; Daida, Jason M.; Bracewell, Ronald N.

    1988-01-01

    The European Space Agency's ERS-1 satellite, as well as others planned to follow, is expected to carry synthetic-aperture radars (SARs) over the polar regions beginning in 1989. A key component in utilization of these SAR data is an automated scheme for extracting the sea-ice velocity field from a time sequence of SAR images of the same geographical region. Two techniques for automated sea-ice tracking, image pyramid area correlation (hierarchical correlation) and feature tracking, are described. Each technique is applied to a pair of Seasat SAR sea-ice images. The results compare well with each other and with manually tracked estimates of the ice velocity. The advantages and disadvantages of these automated methods are pointed out. Using these ice velocity field estimates it is possible to construct one sea-ice image from the other member of the pair. Comparing the reconstructed image with the observed image, errors in the estimated velocity field can be recognized and a useful probable error display created automatically to accompany ice velocity estimates. It is suggested that this error display may be useful in segmenting the sea ice observed into regions that move as rigid plates of significant ice velocity shear and distortion.

  6. High-Altitude Cassini Radar Imaging of Titan

    NASA Astrophysics Data System (ADS)

    West, R. D.; Stiles, B.; Anderson, Y.; Boehmer, R.; Callahan, P.; Gim, Y.; Hamilton, G.; Hensley, S.; Janssen, M.; Johnson, W. T.; Kelleher, K.; Lorenz, R.; Ostro, S.; Paganelli, F.; Shaffer, S.; Wye, L.; Zebker, H.

    2006-12-01

    The Cassini spacecraft is now about halfway through its primary Tour of the Saturn system. By the time of this meeting, the radar instrument will have collected seven synthetic aperture strips during close flyby's, with 13 more to come. These images have resolutions as fine as 300 m. We present here data acquired using another imaging mode, very high altitude synthetic aperture radar (SAR) imaging, which extends imaging radar coverage and increases coincidental coverage with other Cassini imaging instruments such as VIMS and ISS. We also discuss calibration of SAR images and other radar data from additional engineering observations. Here we examine the performance trade-offs, special processing issues, and science potential of the high- altitude image observations, and the latest results from the calibration data. The high-altitude data collections are distinct from the normal Titan radar images because the range is much larger (around 20,000 km vs 950 km to 5000 km for normal SAR passes). To increase the signal to noise ratio in these circumstances, the radar operates in the lowest bandwidth scatterometer mode while spacecraft pointing control is used to slowly pan the central beam across a small swath. These high altitude images incorporate 150-200 independent looks in order to let us discriminate features that may lie below the noise floor. So far, three high-altitude images have been acquired, during Titan flyby's T12, T13, and T15. In T12 imaging was attempted from 37000 km with an effective resolution around 5 km. In T13 the Huygens Probe landing site was imaged from 11000 km with effective resolution of 1 2 km. In T15 the Tsegehi area was imaged from 20000 km with effective resolution of 2 -3 km. Additional high altitude image segments are also planned during the T19 and T20 Titan flyby's. The calibration observations are conducted independently or coupled with a distant icy satellite observation. They consist of receive-only data in all four bandwidths

  7. Space radar image of Washington, D.C.

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This radar image of the Washington, D.C. area demonstrates the capability of imaging radar as a useful tool for urban planners and managers to map and monitor land use patterns. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 150th orbit on April 18, 1994. North is toward the upper right. The Potomac River enters the scene at the top of the image, widens near the center of the image, then runs south and west off the left side of the image. Downtown Washington appears near the center, just to the right of the point where the river widens. The image shows an area 50.3 kilometers by 45.0 kilometers (31.2 miles by 27.9 miles) that is centered at 38.9 degrees north latitude and 77.1 degrees west longitude. The radar illumination is from the left side of the image. The image shows a single channel of SIR-C radar data: L-band, horizontally transmitted and received. State and city boundaries are also visible in the image. Virginia is to the left (southwest) of the Potomac River. Maryland and the District of Columbia are to the right (northeast). The avenues that form the boundary between Maryland and the District of Columbia appear as bright lines because the radar strikes the walls of buildings along the avenues at a perpendicular angle. The dark strip near the center of the image is the National Mall, and the Ellipse and White House grounds can be seen as an adjacent dark patch. The Capital Beltway highway appears as a thin black strip encircling the city. The large dark rectangle near the bottom of the image is Andrews Air Force Base, home of the presidential plane Air Force One. Dark patches to the right of the image represent some of the few remaining agricultural areas in this rapidly expanding metropolitan area.

  8. Geologic Studies of Planetary Surfaces Using Radar Polarimetric Imaging

    NASA Technical Reports Server (NTRS)

    Carter, Lynn M.; Campbell, Donald B.; Campbell, Bruce A.

    2010-01-01

    Radar is a useful remote sensing tool for studying planetary geology because it is sensitive to the composition, structure, and roughness of the surface and can penetrate some materials to reveal buried terrain. The Arecibo Observatory radar system transmits a single sense of circular polarization, and both senses of circular polarization are received, which allows for the construction of the Stokes polarization vector. From the Stokes vector, daughter products such as the circular polarization ratio, the degree of linear polarization, and linear polarization angle are obtained. Recent polarimetric imaging using Arecibo has included Venus and the Moon. These observations can be compared to radar data for terrestrial surfaces to better understand surface physical properties and regional geologic evolution. For example, polarimetric radar studies of volcanic settings on Venus, the Moon and Earth display some similarities, but also illustrate a variety of different emplacement and erosion mechanisms. Polarimetric radar data provides important information about surface properties beyond what can be obtained from single-polarization radar. Future observations using polarimetric synthetic aperture radar will provide information on roughness, composition and stratigraphy that will support a broader interpretation of surface evolution.

  9. Effects of volume averaging on the line spectra of vertical velocity from multiple-Doppler radar observations

    NASA Technical Reports Server (NTRS)

    Gal-Chen, T.; Wyngaard, J. C.

    1982-01-01

    Calculations of the ratio of the true one-dimensional spectrum of vertical velocity and that measured with multiple-Doppler radar beams are presented. It was assumed that the effects of pulse volume averaging and objective analysis routines is replacement of a point measurement with a volume integral. A u and v estimate was assumed to be feasible when orthogonal radars are not available. Also, the target fluid was configured as having an infinite vertical dimension, zero vertical velocity at the top and bottom, and having homogeneous and isotropic turbulence with a Kolmogorov energy spectrum. The ratio obtained indicated that equal resolutions among radars yields a monotonically decreasing, wavenumber-dependent response function. A gain of 0.95 was demonstrated in an experimental situation with 40 levels. Possible errors introduced when using unequal resolution radars were discussed. Finally, it was found that, for some flows, the extent of attenuation depends on the number of vertical levels resolvable by the radars.

  10. Simulation of imaging radar for obstacle avoidance and enhanced vision

    NASA Astrophysics Data System (ADS)

    Doehler, Hans-Ullrich; Bollmeyer, Dirk

    1997-06-01

    One of the main advantages of millimeter wave (MMW) imaging radar systems result from the fact that their imaging performance does nearly not depend on atmospheric affects such as fog, rain and snow. That is the reason that MMW radar seems to be one of the most promising sensors for enhanced vision systems (EVS), which can aid the pilot during approach, landing and taxiing, especially under bad weather conditions. Compared to other imaging devices, MMW radar system deliver a lower image resolution and update rate, and have a worse signal to noise ratio. Moreover, the commonly proposed method of the perspective view projection in EVS applications results in some imaging errors and artifacts. These sensor specific effects should be taken into account during the presently conducted EVS research and development. To get the opportunity of studying imaging radar systems in ground based research environments, we have developed a new type of a MMW radar sensor simulator. Our approach is based on detailed terrain and/or airport databases, as they are available for normal visual simulations or VR applications. We have augmented these databases with some specific attributes which describe object surface properties with respect to MMW. Our approach benefits from the state of the art of high speed computer graphics hard- and software. It is implemented in C/C++ and uses the Open GL graphic standard and the SGI Performer database handler. It runs on every SGI graphic workstation, and achieves an image update rate of about 20 Hz, which is more than actual available radar systems deliver. One of the main advantages of our approach is, that it can be integrated easily in emergent multisensor based enhanced vision systems and it is a useful tool for EVS research and development.

  11. Space Radar Image of Rhine River, France and Germany

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image shows a segment of the Rhine River where it forms the border between the Alsace region of northeastern France on the left and the Black Forest region of Germany on the right. The Rhine, one of the largest and most used waterways in central Europe, winds its way through five countries from the Swiss-Austrian Alps to the North Sea coast of the Netherlands. The river valley is densely populated, as seen in this image, which shows the French city of Strasbourg, the light blue and orange area in the upper left center; and the German cities of Kehl, across the river from Strasbourg and Offenburg, the bright area in right center. The fertile valley is famous for its wine production and most of the agricultural areas in the image, shown in purple patches, are vineyards. The light green areas are forest. Scientists can use radar images like this one to monitor the effects of urban and agricultural development on sensitive ecosystems such as the Rhine River valley. This image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on October 2, 1994. The image is 34.2 kilometers by 33.2 kilometers (21.2 miles by 20.6 miles) and is centered at 48.5 degrees north latitude, 7.7 degrees east longitude. North is toward the upper left. The colors are assigned to different radar frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted and received; green is L-band, horizontally transmitted, vertically received; and blue is C-band, horizontally transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  12. Transmitter passband requirements for imaging radar.

    SciTech Connect

    Doerry, Armin Walter

    2012-12-01

    In high-power microwave power amplifiers for radar, distortion in both amplitude and phase should generally be expected. Phase distortions can be readily equalized. Some amplitude distortions are more problematic than others. In general, especially for SAR using LFM chirps, low frequency modulations such as gain slopes can be tolerated much better than multiple cycles of ripple across the passband of the waveform.

  13. Measuring soil moisture with imaging radars

    NASA Technical Reports Server (NTRS)

    Dubois, Pascale C.; Vanzyl, Jakob; Engman, Ted

    1995-01-01

    An empirical model was developed to infer soil moisture and surface roughness from radar data. The accuracy of the inversion technique is assessed by comparing soil moisture obtained with the inversion technique to in situ measurements. The effect of vegetation on the inversion is studied and a method to eliminate the areas where vegetation impairs the algorithm is described.

  14. Space Radar Image of Washington D.C.

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The city of Washington, D.C., is shown is this space radar image. Images like these are useful tools for urban planners and managers, who use them to map and monitor land use patterns. Downtown Washington is the bright area between the Potomac (upper center to lower left) and Anacostia (middle right) rivers. The dark cross shape that is formed by the National Mall, Tidal Basin, the White House and Ellipse is seen in the center of the image. Arlington National Cemetery is the dark blue area on the Virginia (left) side of the Potomac River near the center of the image. The Pentagon is visible in bright white and red, south of the cemetery. Due to the alignment of the radar and the streets, the avenues that form the boundary between Washington and Maryland appear as bright red lines in the top, right and bottom parts of the image, parallel to the image borders. This image is centered at 38.85 degrees north latitude, 77.05 degrees west longitude. North is toward the upper right. The area shown is approximately 29 km by 26 km (18 miles by 16 miles). Colors are assigned to different frequencies and polarizations of the radar as follows: Red is the L-band horizontally transmitted, horizontally received; green is the L-band horizontally transmitted, vertically received; blue is the C-band horizontally transmitted, vertically received. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture (SIR-C/X-SAR) imaging radar when it flew aboard the space shuttle Endeavour on April 18, 1994. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  15. The Shuttle Imaging Radar B (SIR-B) experiment report

    NASA Technical Reports Server (NTRS)

    Cimino, Jo Bea; Holt, Benjamin; Richardson, Annie

    1988-01-01

    The primary objective of the SIR-B experiment was to acquire multiple-incidence-angle radar imagery of a variety of Earth's surfaces to better understand the effects of imaging geometry on radar backscatter. A complementary objective was to map extensive regions of particular interest. Under these broad objectives, many specific scientific experiments were defined by the 43 SIR-B Science Team members, including studies in the area of geology, vegetation, radar penetration, oceanography, image analysis, and calibration technique development. Approximately 20 percent of the planned digital data were collected, meeting 40 percent of the scientific objectives. This report is an overview of the SIR-B experiment and includes the science investigations, hardware design, mission scenario, mission operations, events of the actual missions, astronaut participation, data products (including auxiliary data), calibrations, and a summary of the actual coverage. Also included are several image samples.

  16. Fisheries imaging radar surveillance test /FIRST/ - Bering Sea test

    NASA Technical Reports Server (NTRS)

    Woods, E. G.; Ivey, J. H.

    1977-01-01

    A joint NOAA, U.S. Coast Guard and NASA program is being conducted to determine if a synthetic aperture radar (SAR) system, such as planned for NASA's SEASAT, can be useful in monitoring fishing vessels within the newly established 200-mile fishing limit. As part of this program, data gathering field operations were conducted over concentrations of foreign fishing vessels in the Bering Sea off Alaska in April 1976. The Jet Propulsion Laboratory developed synthetic aperture L-band radar which was flown aboard the NASA Convair 990 aircraft, with a Coast Guard cutter and C-130 aircraft simultaneously gathering data to provide both radar imagery and sea truth information on the vessels being imaged. Results indicate that synthetic aperture radar systems have potential for all weather detection, enumeration and classification of fishing vessels.

  17. Oil Spill Dectection by Imaging Radars: Challenges and Pitfalls

    NASA Astrophysics Data System (ADS)

    Alpers, Werner; Zeng, Kan; Tang, DanLing

    2016-08-01

    Criteria for discriminating between radar signatures of oil films and oil-spill look-alikes visible on synthetic aperture radar (SAR) images of the sea surface are critically reviewed. The main challenge in oil spill detection using SAR is to discriminate between mineral oil films and biogenic slicks originating from secretions (exudations) of biota in the water column. The claim that oil spill detection algorithms based on measuring 1) the reduction of the normalized radar cross section (NRCS), 2) the differences in the geometry and shape of the surface films, and 3) the differences in texture have a high success rate is questioned. Furthermore, it is questioned that polarimetric SAR data are of great help for discriminating between mineral oil films and biogenic slicks. However, differences in the statistical behavior of the radar backscattering is expected due to the fact that, other than monomolecular biogenic surface films, mineral oil films can form multi-layers.

  18. Space Radar Image of Long Valley, California in 3-D

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This three-dimensional perspective view of Long Valley, California was created from data taken by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar on board the space shuttle Endeavour. This image was constructed by overlaying a color composite SIR-C radar image on a digital elevation map. The digital elevation map was produced using radar interferometry, a process by which radar data are acquired on different passes of the space shuttle. The two data passes are compared to obtain elevation information. The interferometry data were acquired on April 13,1994 and on October 3, 1994, during the first and second flights of the SIR-C/X-SAR instrument. The color composite radar image was taken in October and was produced by assigning red to the C-band (horizontally transmitted and vertically received) polarization; green to the C-band (vertically transmitted and received) polarization; and blue to the ratio of the two data sets. Blue areas in the image are smooth and yellow areas are rock outcrops with varying amounts of snow and vegetation. The view is looking north along the northeastern edge of the Long Valley caldera, a volcanic collapse feature created 750,000 years ago and the site of continued subsurface activity. Crowley Lake is the large dark feature in the foreground. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are

  19. Space Radar Image of Orange County, California (annotated version)

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image of Orange County, Calif., shows the massive urbanization of this rapidly growing region located just south of Los Angeles. Orange County, sandwiched between rugged mountains and the Pacific Ocean, includes the communities of Anaheim, Santa Ana and Huntington Beach. Anaheim Stadium can be seen in the upper center of the image, as a small white ring to the right of a major freeway intersection. The large dark blue rectangular area in the upper left is the Seal Beach Naval Weapons Station and adjacent wildlife refuge. Runways of the El Toro Marine Air Station appear as a black 'x' near the center of the image. The large purple area to the left of the the Air Station and extending to the coast is the scar left by the Laguna wildfire of October 1993. The sparse vegetation left in the wake of the fire provides a weak source of radar echoes, making the burn areas distinctively dark in the image. Another large burn area, from the Ortega fire of 1993, is seen in the mountains in the lower right of the image. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on October 3, 1994. The image is centered at 33.7 degrees north latitude and 117.7 degrees west longitude. North is toward the upper right. The image shows an area 66.2 kilometers by 44.2 kilometers (41.0 miles by 27.4 miles). The colors are assigned todifferent frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted, horizontally received; green is L-band, horizontally transmitted, vertically received; blue is C-band, horizontally transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  20. Field assessment of noncontact stream gauging using portable surface velocity radars (SVR)

    NASA Astrophysics Data System (ADS)

    Welber, Matilde; Le Coz, Jérôme; Laronne, Jonathan B.; Zolezzi, Guido; Zamler, Daniel; Dramais, Guillaume; Hauet, Alexandre; Salvaro, Martino

    2016-02-01

    The applicability of a portable, commercially available surface velocity radar (SVR) for noncontact stream gauging was evaluated through a series of field-scale experiments carried out in a variety of sites and deployment conditions. Comparisons with various concurrent techniques showed acceptable agreement with velocity profiles, with larger uncertainties close to the banks. In addition to discharge error sources shared with intrusive velocity-area techniques, SVR discharge estimates are affected by flood-induced changes in the bed profile and by the selection of a depth-averaged to surface velocity ratio, or velocity coefficient (α). Cross-sectional averaged velocity coefficients showed smaller fluctuations and closer agreement with theoretical values than those computed on individual verticals, especially in channels with high relative roughness. Our findings confirm that α = 0.85 is a valid default value, with a preferred site-specific calibration to avoid underestimation of discharge in very smooth channels (relative roughness ˜ 0.001) and overestimation in very rough channels (relative roughness > 0.05). Theoretically derived and site-calibrated values of α also give accurate SVR-based discharge estimates (within 10%) for low and intermediate roughness flows (relative roughness 0.001 to 0.05). Moreover, discharge uncertainty does not exceed 10% even for a limited number of SVR positions along the cross section (particularly advantageous to gauge unsteady flood flows and very large floods), thereby extending the range of validity of rating curves.

  1. Radar image with color as height, Bahia State, Brazil

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This radar image is the first to show the full 240-kilometer-wide (150 mile)swath collected by the Shuttle Radar Topography Mission (SRTM). The area shown is in the state of Bahia in Brazil. The semi-circular mountains along the leftside of the image are the Serra Da Jacobin, which rise to 1100 meters (3600 feet) above sea level. The total relief shown is approximately 800 meters (2600 feet). The top part of the image is the Sertao, a semi-arid region, that is subject to severe droughts during El Nino events. A small portion of the San Francisco River, the longest river (1609 kilometers or 1000 miles) entirely within Brazil, cuts across the upper right corner of the image. This river is a major source of water for irrigation and hydroelectric power. Mapping such regions will allow scientists to better understand the relationships between flooding cycles, drought and human influences on ecosystems.

    This image combines two types of data from the Shuttle Radar Topography Mission. The image brightness corresponds to the strength of the radar signal reflected from the ground, while colors show the elevation as measured by SRTM. The three dark vertical stripes show the boundaries where four segments of the swath are merged to form the full scanned swath. These will be removed in later processing. Colors range from green at the lowest elevations to reddish at the highest elevations.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space

  2. Remote sensing with spaceborne synthetic aperture imaging radars: A review

    NASA Technical Reports Server (NTRS)

    Cimino, J. B.; Elachi, C.

    1983-01-01

    A review is given of remote sensing with Spaceborne Synthetic Aperture Radars (SAR's). In 1978, a spaceborne SA was flown on the SEASAT satellite. It acquired high resulution images over many regions in North America and the North Pacific. The acquired data clearly demonstrate the capability of spaceborne SARs to: image and track polar ice floes; image ocean surface patterns including swells, internal waves, current boundaries, weather boundaries and vessels; and image land features which are used to acquire information about the surface geology and land cover. In 1981, another SAR was flown on the second shuttle flight. This Shuttle Imaging Radar (SIR-A) acquired land and ocean images over many areas around the world. The emphasis of the SIR-A experiment was mainly toward geologic mapping. Some of the key results of the SIR-A experiment are given.

  3. Observations of seasonal and diurnal glacier velocities at Mount Rainier, Washington, using terrestrial radar interferometry

    NASA Astrophysics Data System (ADS)

    Allstadt, K. E.; Shean, D. E.; Campbell, A.; Fahnestock, M.; Malone, S. D.

    2015-12-01

    We present surface velocity maps derived from repeat terrestrial radar interferometry (TRI) measurements and use these time series to examine seasonal and diurnal dynamics of alpine glaciers at Mount Rainier, Washington. We show that the Nisqually and Emmons glaciers have small slope-parallel velocities near the summit (< 0.2 m day-1), high velocities over their upper and central regions (1.0-1.5 m day-1), and stagnant debris-covered regions near the terminus (< 0.05 m day-1). Velocity uncertainties are as low as ±0.02-0.08 m day-1. We document a large seasonal velocity decrease of 0.2-0.7 m day-1 (-25 to -50 %) from July to November for most of the Nisqually Glacier, excluding the icefall, suggesting significant seasonal subglacial water storage under most of the glacier. We did not detect diurnal variability above the noise level. Simple 2-D ice flow modeling using TRI velocities suggests that sliding accounts for 91 and 99 % of the July velocity field for the Emmons and Nisqually glaciers with possible ranges of 60-97 and 93-99.5 %, respectively, when considering model uncertainty. We validate our observations against recent in situ velocity measurements and examine the long-term evolution of Nisqually Glacier dynamics through comparisons with historical velocity data. This study shows that repeat TRI measurements with > 10 km range can be used to investigate spatial and temporal variability of alpine glacier dynamics over large areas, including hazardous and inaccessible areas.

  4. Imaging Radar in the Mojave Desert-Death Valley Region

    NASA Technical Reports Server (NTRS)

    Farr, Tom G.

    2001-01-01

    The Mojave Desert-Death Valley region has had a long history as a test bed for remote sensing techniques. Along with visible-near infrared and thermal IR sensors, imaging radars have flown and orbited over the area since the 1970's, yielding new insights into the geologic applications of these technologies. More recently, radar interferometry has been used to derive digital topographic maps of the area, supplementing the USGS 7.5' digital quadrangles currently available for nearly the entire area. As for their shorter-wavelength brethren, imaging radars were tested early in their civilian history in the Mojave Desert-Death Valley region because it contains a variety of surface types in a small area without the confounding effects of vegetation. The earliest imaging radars to be flown over the region included military tests of short-wavelength (3 cm) X-band sensors. Later, the Jet Propulsion Laboratory began its development of imaging radars with an airborne sensor, followed by the Seasat orbital radar in 1978. These systems were L-band (25 cm). Following Seasat, JPL embarked upon a series of Space Shuttle Imaging Radars: SIRA (1981), SIR-B (1984), and SIR-C (1994). The most recent in the series was the most capable radar sensor flown in space and acquired large numbers of data swaths in a variety of test areas around the world. The Mojave Desert-Death Valley region was one of those test areas, and was covered very well with 3 wavelengths, multiple polarizations, and at multiple angles. At the same time, the JPL aircraft radar program continued improving and collecting data over the Mojave Desert Death Valley region. Now called AIRSAR, the system includes 3 bands (P-band, 67 cm; L-band, 25 cm; C-band, 5 cm). Each band can collect all possible polarizations in a mode called polarimetry. In addition, AIRSAR can be operated in the TOPSAR mode wherein 2 antennas collect data interferometrically, yielding a digital elevation model (DEM). Both L-band and C-band can be

  5. Los Angeles, California, Radar Image, Wrapped Color as Height

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This topographic radar image shows the relationships of the dense urban development of Los Angeles and the natural contours of the land. The image includes the Pacific Ocean on the left, the flat Los Angeles Basin across the center, and the steep ranges of the Santa Monica and Verdugo mountains along the top. The two dark strips near the coast at lower left are the runways of Los Angeles International Airport. Downtown Los Angeles is the bright yellow and pink area at lower center. Pasadena, including the Rose Bowl, are seen half way down the right edge of the image. The communities of Glendale and Burbank, including the Burbank Airport, are seen at the center of the top edge of the image. Hazards from earthquakes, floods and fires are intimately related to the topography in this area. Topographic data and other remote sensing images provide valuable information for assessing and mitigating the natural hazards for cities such as Leangles.

    This image combines two types of data from the Shuttle Radar Topography Mission. The image brightness corresponds to the strength of the radar signal reflected from the ground, while colors show the elevation as measured by SRTM. Each cycle of colors (from pink through blue back to pink) represents an equal amount of elevation difference (400 meters, or 1300 feet) similar to contour lines on a standard topographic map. This image contains about 2400 meters (8000 feet) of total relief.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between

  6. Space Radar Image of Kilauea, Hawaii - interferometry 1

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This X-band image of the volcano Kilauea was taken on October 4, 1994, by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar. The area shown is about 9 kilometers by 13 kilometers (5.5 miles by 8 miles) and is centered at about 19.58 degrees north latitude and 155.55 degrees west longitude. This image and a similar image taken during the first flight of the radar instrument on April 13, 1994 were combined to produce the topographic information by means of an interferometric process. This is a process by which radar data acquired on different passes of the space shuttle is overlaid to obtain elevation information. Three additional images are provided showing an overlay of radar data with interferometric fringes; a three-dimensional image based on altitude lines; and, finally, a topographic view of the region. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.V.(DLR), the major partner in science, operations and data processing of X-SAR. The Instituto Ricerca Elettromagnetismo

  7. A model for radar images and its application to adaptive digital filtering of multiplicative noise

    NASA Technical Reports Server (NTRS)

    Frost, V. S.; Stiles, J. A.; Shanmugan, K. S.; Holtzman, J. C.

    1982-01-01

    Standard image processing techniques which are used to enhance noncoherent optically produced images are not applicable to radar images due to the coherent nature of the radar imaging process. A model for the radar imaging process is derived in this paper and a method for smoothing noisy radar images is also presented. The imaging model shows that the radar image is corrupted by multiplicative noise. The model leads to the functional form of an optimum (minimum MSE) filter for smoothing radar images. By using locally estimated parameter values the filter is made adaptive so that it provides minimum MSE estimates inside homogeneous areas of an image while preserving the edge structure. It is shown that the filter can be easily implemented in the spatial domain and is computationally efficient. The performance of the adaptive filter is compared (qualitatively and quantitatively) with several standard filters using real and simulated radar images.

  8. Observations of vertical velocity power spectra with the SOUSY VHF radar

    NASA Technical Reports Server (NTRS)

    Larsen, M. F.; Rottger, J.; Holden, D. N.

    1986-01-01

    A data set taken with the SOUSY VHF radar from October 28 to November 13, 1981 was used to calculate the power spectrum of the vertical velocities directly from the vertical beam measurements. The spectral slopes for the frequency spectra have been determined out to periods of several days and have been found to have values near -1 in the troposphere and shallower slopes in the lower stratosphere. The value of -1 is in agreement with the value found by Larsen et al. (1985) and Balsley and Carter (1982) in the range from a few minutes to 1 hr.

  9. Patches of polar mesospheric summer echoes characterized from radar imaging observations with MAARSY

    NASA Astrophysics Data System (ADS)

    Sommer, Svenja; Chau, Jorge L.

    2016-12-01

    A recent study has hypothesized that polar mesospheric summer echoes (PMSEs) might consist mainly of localized isotropic scattering. These results have been inferred from indirect measurements. Using radar imaging with the Middle Atmosphere Alomar Radar System (MAARSY), we observed horizontal structures that support our previous findings. We observe that small-scale irregularities, causing isotropic scattering, are organized in patches. We find that patches of PMSEs, as observed by the radar, are usually smaller than 1 km. These patches occur throughout the illuminated volume, supporting that PMSEs are caused by localized isotropic or inhomogeneous scattering. Furthermore, we show that imaging can be used to identify side lobe detections, which have a significant influence even for narrow beam observations. Improved spectra estimations are obtained by selecting the desired volume to study parameters such as spectral width and to estimate the derived energy dissipation rates. In addition, a combined wide beam experiment and radar imaging is used to resolve the radial velocity and spectral width at different volumes within the illuminated volume.

  10. Space Radar Image Isla Isabela in 3-D

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a three-dimensional view of Isabela, one of the Galapagos Islands located off the western coast of Ecuador, South America. This view was constructed by overlaying a Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) image on a digital elevation map produced by TOPSAR, a prototype airborne interferometric radar which produces simultaneous image and elevation data. The vertical scale in this image is exaggerated by a factor of 1.87. The SIR-C/X-SAR image was taken on the 40th orbit of space shuttle Endeavour. The image is centered at about 0.5 degree south latitude and 91 degrees west longitude and covers an area of 75 by 60 kilometers (47 by 37 miles). The radar incidence angle at the center of the image is about 20 degrees. The western Galapagos Islands, which lie about 1,200 kilometers (750 miles)west of Ecuador in the eastern Pacific, have six active volcanoes similar to the volcanoes found in Hawaii and reflect the volcanic processes that occur where the ocean floor is created. Since the time of Charles Darwin's visit to the area in 1835, there have been more than 60 recorded eruptions on these volcanoes. This SIR-C/X-SAR image of Alcedo and Sierra Negra volcanoes shows the rougher lava flows as bright features, while ash deposits and smooth pahoehoe lava flows appear dark. Vertical exaggeration of relief is a common tool scientists use to detect relationships between structure (for example, faults, and fractures) and topography. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data

  11. Blind-velocity SAR/ISAR imaging of a moving target in a stationary background.

    PubMed

    Yang, H; Soumekh, M

    1993-01-01

    A synthetic aperture radio/inverse synthetic aperture radar (SAR/ISAR) coherent system model and inversion to image a target moving with an unknown constant velocity in a stationary background are presented. The approach is based on a recently developed system modelling and inversion principle for SAR/ISAR imaging that utilizes the spatial Fourier decomposition of SAR data in the synthetic aperture domain to convert the SAR system model's nonlinear phase functions into linear phase functions suitable for a computationally manageable inversion. It is shown that SAR/ISAR imaging of a moving target can be converted into imaging the target in a stationary squint-mode SAR problem where the parameters of the squint-mode geometry depend on the target's velocity. A method for estimating the moving target's velocity that utilizes a spatial Doppler analysis of the SAR data within overlapping subapertures is presented. The spatial Doppler technique does not require the radar signal to be narrowband, so the reconstructed image's resolution is not sacrificed to improve the target's velocity estimator.

  12. Three-dimensional surface velocities of Storstrømmen glacier, Greenland, derived from radar interferometry and ice-sounding radar measurements

    NASA Astrophysics Data System (ADS)

    Reeh, Niels; Mohr, Johan Jacob; Nørvang Madsen, Søren; Oerter, Hans; Gundestrup, Niels S.

    Non-steady-state vertical velocities of up to 5 m a-1 exceed the vertical surface-parallel flow (SPF) components over much of the ablation area of Storstrømmen, a large outlet glacier from the East Greenland ice sheet. Neglecting a contribution to the vertical velocity of this magnitude results in substantial errors (up to 20%) also on the south-north component of horizontal velocities derived by satellite synthetic aperture radar interferometry (InSAR) measurements. In many glacier environments, the steady-state vertical velocity component required to balance the annual ablation rate is 5-10m a-1 or more.This indicates that the SPFassumption may be problematic also for glaciers in steady state. Here we derive the three-dimensional surface velocity distribution of Storstrømmen by using the principle of mass conservation (MC) to combine InSAR measurements from ascending and descending satellite tracks with airborne ice-sounding radar measurement of ice thickness. The results are compared to InSAR velocities previously derived by using the SPF assumption, and to velocities obtained by in situ global positioning system (GPS) measurements. The velocities derived by using the MC principle are in better agreement with the GPS velocities than the previously calculated velocities derived with the SPFassumption.

  13. Logarithmic Laplacian Prior Based Bayesian Inverse Synthetic Aperture Radar Imaging.

    PubMed

    Zhang, Shuanghui; Liu, Yongxiang; Li, Xiang; Bi, Guoan

    2016-04-28

    This paper presents a novel Inverse Synthetic Aperture Radar Imaging (ISAR) algorithm based on a new sparse prior, known as the logarithmic Laplacian prior. The newly proposed logarithmic Laplacian prior has a narrower main lobe with higher tail values than the Laplacian prior, which helps to achieve performance improvement on sparse representation. The logarithmic Laplacian prior is used for ISAR imaging within the Bayesian framework to achieve better focused radar image. In the proposed method of ISAR imaging, the phase errors are jointly estimated based on the minimum entropy criterion to accomplish autofocusing. The maximum a posterior (MAP) estimation and the maximum likelihood estimation (MLE) are utilized to estimate the model parameters to avoid manually tuning process. Additionally, the fast Fourier Transform (FFT) and Hadamard product are used to minimize the required computational efficiency. Experimental results based on both simulated and measured data validate that the proposed algorithm outperforms the traditional sparse ISAR imaging algorithms in terms of resolution improvement and noise suppression.

  14. Space Radar Image of Missoula, Montana in 3-D

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a three-dimensional perspective view of Missoula, Montana, created by combining two spaceborne radar images using a technique known as interferometry. Visualizations like this are useful because they show scientists the shapes of the topographic features such as mountains and valleys. This technique helps to clarify the relationships of the different types of materials on the surface detected by the radar. The view is looking north-northeast. The blue circular area at the lower left corner is a bend of the Bitterroot River just before it joins the Clark Fork, which runs through the city. Crossing the Bitterroot River is the bridge of U.S. Highway 93. Highest mountains in this image are at elevations of 2,200 meters (7,200 feet). The city is about 975 meters (3,200 feet) above sea level. The bright yellow areas are urban and suburban zones, dark brown and blue-green areas are grasslands, bright green areas are farms, light brown and purple areas are scrub and forest, and bright white and blue areas are steep rocky slopes. The two radar images were taken on successive days by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour in October 1994. The digital elevation map was produced using radar interferometry, a process in which radar data are acquired on different passes of the space shuttle. The two data passes are compared to obtain elevation information. Radar image data are draped over the topography to provide the color with the following assignments: red is L-band vertically transmitted, vertically received; green is C-band vertically transmitted, vertically received; and blue are differences seen in the L-band data between the two days. This image is centered near 46.9 degrees north latitude and 114.1 degrees west longitude. No vertical exaggeration factor has been applied to the data. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA

  15. Space Radar Image of Pinacate Volcanic Field, Mexico

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image shows the Pinacate Volcanic Field in the state of Sonora, Mexico, about 150 kilometers (93 miles) southeast of Yuma, Arizona. The United States/Mexico border runs across the upper right corner of the image. More than 300 volcanic vents occur in the Pinacate field, including cinder cones that experienced small eruptions as recently as 1934. The larger circular craters seen in the image are a type of volcano known as a 'maar', which erupts violently when rising magma encounters groundwater, producing highly pressurized steam that powers explosive eruptions. The highest elevations in the volcanic field, about 1200 meters (4000 feet), occur in the 'shield volcano' structure shown in bright white, occupying most of the left half of the image. Numerous cinder cones dot the flanks of the shield. The yellow patches to the right of center are newer, rough-textured lava flows that strongly reflect the long wavelength radar signals. Along the left edge of the image are sand dunes of the Gran Desierto. The dark areas are smooth sand and the brighter brown and purple areas have vegetation on the surface. Radar data provide a unique means to study the different types of lava flows and wind-blown sands. This image was acquired by Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on April 18, 1994. The image is 57 kilometers by 48 kilometers (35 miles by 30 miles) and is centered at 31.7 degrees north latitude, 113.4 degrees West longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted and received; green is L-band, horizontally transmitted, vertically received; and blue is C-band, horizontally transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian, and United States space agencies, is part of NASA's Mission to Planet Earth.

  16. Honolulu, Hawaii Radar Image, Wrapped Color as Height

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This topographic radar image shows the city of Honolulu, Hawaii and adjacent areas on the island of Oahu. Honolulu lies on the south shore of the island, right of center of the image. Just below the center is Pearl Harbor, marked by several inlets and bays. Runways of the airport can be seen to the right of Pearl Harbor. Diamond Head, an extinct volcanic crater, is a blue circle along the coast right of center. The Koolau mountain range runs through the center of the image. The steep cliffs on the north side of the range are thought to be remnants of massive landslides that ripped apart the volcanic mountains that built the island thousands of years ago. On the north shore of the island are the Mokapu Peninsula and Kaneohe Bay. High resolution topographic data allow ecologists and planners to assess the effects of urban development on the sensitive ecosystems in tropical regions.

    This image combines two types of data from the Shuttle Radar Topography Mission. The image brightness corresponds to the strength of the radar signal reflected from the ground, while colors show the elevation as measured by SRTM. Each cycle of colors (from pink through blue back to pink) represents an equal amount of elevation difference (400 meters, or 1300 feet) similar to contour lines on a standard topographic map. This image contains about 2400 meters (8000 feet) of total relief.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA

  17. San Gabriel Mountains, California, Radar image, color as height

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This topographic radar image shows the relationship of the urban area of Pasadena, California to the natural contours of the land. The image includes the alluvial plain on which Pasadena and the Jet Propulsion Laboratory sit, and the steep range of the San Gabriel Mountains. The mountain front and the arcuate valley running from upper left to the lower right are active fault zones, along which the mountains are rising. The chaparral-covered slopes above Pasadena are also a prime area for wildfires and mudslides. Hazards from earthquakes, floods and fires are intimately related to the topography in this area. Topographic data and other remote sensing images provide valuable information for assessing and mitigating the natural hazards for cities along the front of active mountain ranges.

    This image combines two types of data from the Shuttle Radar Topography Mission. The image brightness corresponds to the strength of the radar signal reflected from the ground, while colors show the elevation as measured by SRTM. Colors range from blue at the lowest elevations to white at the highest elevations. This image contains about 2300 meters (7500 feet) of total relief. White speckles on the face of some of the mountains are holes in the data caused by steep terrain. These will be filled using coverage from an intersecting pass.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency

  18. Vertical group and phase velocities of ionospheric waves derived from the MU radar

    NASA Astrophysics Data System (ADS)

    Liu, J. Y.; Hsiao, C. C.; Liu, C. H.; Yamamoto, M.; Fukao, S.; Lue, H. Y.; Kuo, F. S.

    2007-08-01

    The middle- and upper-atmosphere (MU) radar (34.85°N, 136.10°E) was operated in the incoherent scatter power-only mode to observe the ionosphere during 17 June 2001. Pronounced 200- to 300-min. waves in the echo power appeared in the F2 region during 0240-1250 local time on 17 June 2001. A procedure of Fourier analyses is conducted to derive power spectra, vertical phase, and group velocities of the pronounced waves. Results show that the center frequency of the waves is a function of the wave number. The opposite directions of the vertical phase and group velocities imply the presence of atmospheric gravity waves.

  19. Space Radar Image of Great Wall of China

    NASA Technical Reports Server (NTRS)

    1994-01-01

    These radar images show two segments of the Great Wall of China in a desert region of north-central China, about 700 kilometers (434 miles) west of Beijing. The wall appears as a thin orange band, running from the top to the bottom of the left image, and from the middle upper-left to the lower-right of the right image. These segments of the Great Wall were constructed in the 15th century, during the Ming Dynasty. The wall is between 5 and 8 meters high (16 to 26 feet) in these areas. The entire wall is about 3,000 kilometers (1,864 miles) long and about 150 kilometers (93 miles) of the wall appear in these two images. The wall is easily detected from space by radar because its steep, smooth sides provide a prominent surface for reflection of the radar beam. Near the center of the left image, two dry lake beds have been developed for salt extraction. Rectangular patterns in both images indicate agricultural development, primarily wheat fields. The images were acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on April 10, 1994. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. The left image is centered at 37.7 degrees North latitude and 107.5 degrees East longitude. The right image is centered at 37.5 degrees North latitude and 108.1 degrees East longitude. North is toward the upper right. Each area shown measures 25 kilometers by 75 kilometers (15.5 miles by 45.5 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, horizontally received; green is L-band horizontally transmitted, vertically received; blue is C-band horizontally transmitted, vertically received.

  20. Fast high-resolution terahertz radar imaging at 25 meters

    NASA Astrophysics Data System (ADS)

    Cooper, Ken B.; Dengler, Robert J.; Llombart, Nuria; Talukder, Ashit; Panangadan, Anand V.; Peay, Chris S.; Mehdi, Imran; Siegel, Peter H.

    2010-04-01

    We report improvements in the scanning speed and standoff range of an ultra-wide bandwidth terahertz (THz) imaging radar for person-borne concealed object detection. Fast beam scanning of the single-transceiver radar is accomplished by rapidly deflecting a flat, light-weight subreflector in a confocal Gregorian optical geometry. With RF back-end improvements also implemented, the radar imaging rate has increased by a factor of about 30 compared to that achieved previously in a 4 m standoff prototype instrument. In addition, a new 100 cm diameter ellipsoidal aluminum reflector yields beam spot diameters of approximately 1 cm over a 50×50 cm field of view at a range of 25 m, although some aberrations are observed that probably arise from misaligned optics. Through-clothes images of concealed pipes at 25 m range, acquired in 5 seconds, are presented, and the impact of reduced signal-to-noise from an even faster frame rate is analyzed. These results inform the requirements for eventually achieving sub-second or video-rate THz radar imaging.

  1. Fast, High-Resolution Terahertz Radar Imaging at 25 Meters

    NASA Technical Reports Server (NTRS)

    Cooper, Ken B.; Dengler, Robert J.; Llombart, Nuria; Talukder, Ashit; Panangadan, Anand V.; Peay, Chris S.; Siegel, Peter H.

    2010-01-01

    We report improvements in the scanning speed and standoff range of an ultra-wide bandwidth terahertz (THz) imaging radar for person-borne concealed object detection. Fast beam scanning of the single-transceiver radar is accomplished by rapidly deflecting a flat, light-weight subreflector in a confocal Gregorian optical geometry. With RF back-end improvements also implemented, the radar imaging rate has increased by a factor of about 30 compared to that achieved previously in a 4 m standoff prototype instrument. In addition, a new 100 cm diameter ellipsoidal aluminum reflector yields beam spot diameters of approximately 1 cm over a 50x50 cm field of view at a range of 25 m, although some aberrations are observed that probably arise from misaligned optics. Through-clothes images of a concealed threat at 25 m range, acquired in 5 seconds, are presented, and the impact of reduced signal-to-noise from an even faster frame rate is analyzed. These results inform the system requirements for eventually achieving sub-second or video-rate THz radar imaging.

  2. Roadside IED detection using subsurface imaging radar and rotary UAV

    NASA Astrophysics Data System (ADS)

    Qin, Yexian; Twumasi, Jones O.; Le, Viet Q.; Ren, Yu-Jiun; Lai, C. P.; Yu, Tzuyang

    2016-05-01

    Modern improvised explosive device (IED) and mine detection sensors using microwave technology are based on ground penetrating radar operated by a ground vehicle. Vehicle size, road conditions, and obstacles along the troop marching direction limit operation of such sensors. This paper presents a new conceptual design using a rotary unmanned aerial vehicle (UAV) to carry subsurface imaging radar for roadside IED detection. We have built a UAV flight simulator with the subsurface imaging radar running in a laboratory environment and tested it with non-metallic and metallic IED-like targets. From the initial lab results, we can detect the IED-like target 10-cm below road surface while carried by a UAV platform. One of the challenges is to design the radar and antenna system for a very small payload (less than 3 lb). The motion compensation algorithm is also critical to the imaging quality. In this paper, we also demonstrated the algorithm simulation and experimental imaging results with different IED target materials, sizes, and clutters.

  3. An improved version of the extended velocity-azimuth display analysis of single-Doppler radar data

    NASA Astrophysics Data System (ADS)

    Matejka, Thomas; Srivastava, Ramesh C.

    1991-08-01

    Extended velocity-azimuth display (EVAD) analysis is useful for obtaining vertical profiles of horizontal divergence, vertical air velocity, vertical hydrometer velocity, and hydrometeor terminal fall speed in widespread precipitation. The technique uses a volume of velocity data collected with a single Doppler radar. Several improvements to the previously reported EVAD technique are discussed. They include the weighting of Fourier series coefficients to reflect their estimated error, a correction for heteroscedasticity (the systematic variation of residuals) in the regression analysis, and the weighting of data from different elevation angles to compensate for the finite thickness of the layers in which each analysis is performed. Vertical air velocity is obtained through a variational procedure. Procedures for dealiasing the velocity data and for rejecting outliers from the dataset are summarized. Recommendations for collecting radar data for use in EVAD analysis are made.

  4. Experimental 0.22 THz Stepped Frequency Radar System for ISAR Imaging

    NASA Astrophysics Data System (ADS)

    Liang, Mei Yan; Zhang, Cun Lin; Zhao, Ran; Zhao, Yue Jin

    2014-09-01

    High resolution inverse synthetic aperture radar (ISAR) imaging is demonstrated by using a 0.22 THz stepped-frequency (SF) imaging radar system. The synthesis bandwidth of the terahertz (THz) SF radar is 12 GHz, which are beneficial for high resolution imaging. The resolution of ISAR image can reach centimeter-scale with the use of Range-Doppler algorithm (RDA). Results indicate that high resolution ISAR imaging is realized by using 0.22THz SF radar coupled with turntable scanning, which can provide foundations for further research on high-resolution radar image in the THz band.

  5. The role of space borne imaging radars in environmental monitoring: Some shuttle imaging radar results in Asia

    NASA Technical Reports Server (NTRS)

    Imhoff, M.; Vermillion, C.

    1986-01-01

    The synoptic view afforded by orbiting Earth sensors can be extremely valuable for resource evaluation, environmental monitoring and development planning. For many regions of the world, however, cloud cover has prevented the acquisition of remotely sensed data during the most environmentally stressful periods of the year. This paper discusses how synthetic aperture imaging radar can be used to provide valuable data about the condition of the Earth's surface during periods of bad weather. Examples are given of applications using data from the Shuttle Imaging Radars (SIR) A and B for agriculture land use and crop condition assessment, monsoon flood boundary and flood damage assessment, water resource monitoring and terrain modeling, coastal forest mapping and vegetation penetration, and coastal development monitoring. Recent SIR-B results in Bangladesh are emphasized, radar system basics are reviewed and future SAR systems discussed.

  6. The role of space borne imaging radars in environmental monitoring: Some shuttle imaging radar results in Asia

    NASA Technical Reports Server (NTRS)

    Imhoff, Marc L.; Vermillion, C. H.

    1986-01-01

    The synoptic view afforded by orbiting Earth sensors can be extremely valuable for resource evaluation, environmental monitoring and development planning. For many regions of the world, however, cloud cover has prevented the acquisition of remotely sensed data during the most environmentally stressful periods of the year. How synthetic aperture imaging radar can be used to provide valuable data about the condition of the Earth's surface during periods of bad weather is discussed. Examples are given of applications using data from the Shuttle Imaging Radars (SIR) A and B for agricultural land use and crop condition assessment, monsoon flood boundary and flood damage assessment, water resource monitoring and terrain modeling, coastal forest mapping and vegetation penetration, and coastal development monitoring. Recent SIR-B results in Bangladesh are emphasized, radar system basics are reviewed and future SAR systems are discussed.

  7. Space Radar Image of Manaus region of Brazil

    NASA Technical Reports Server (NTRS)

    1994-01-01

    These L-band images of the Manaus region of Brazil were acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour. The left image was acquired on April 12, 1994, and the middle image was acquired on October 3, 1994. The area shown is approximately 8 kilometers by 40 kilometers (5 miles by 25 miles). The two large rivers in this image, the Rio Negro (top) and the Rio Solimoes (bottom), combine at Manaus (west of the image) to form the Amazon River. The image is centered at about 3 degrees south latitude and 61 degrees west longitude. North is toward the top left of the images. The differences in brightness between the images reflect changes in the scattering of the radar channel. In this case, the changes are indicative of flooding. A flooded forest has a higher backscatter at L-band (horizontally transmitted and received) than an unflooded river. The extent of the flooding is much greater in the April image than in the October image, and corresponds to the annual, 10-meter (33-foot) rise and fall of the Amazon River. A third image at right shows the change in the April and October images and was created by determining which areas had significant decreases in the intensity of radar returns. These areas, which appear blue on the third image at right, show the dramatic decrease in the extent of flooded forest, as the level of the Amazon River falls. The flooded forest is a vital habitat for fish and floating meadows are an important source of atmospheric methane. This demonstrates the capability of SIR-C/X-SAR to study important environmental changes that are impossible to see with optical sensors over regions such as the Amazon, where frequent cloud cover and dense forest canopies obscure monitoring of floods. Field studies by boat, on foot and in low-flying aircraft by the University of California at Santa Barbara, in collaboration with Brazil's Instituto Nacional de Pesguisas Estaciais, during

  8. Bistatic synthetic aperture radar imaging using ultraNarrowband continuous waveforms.

    PubMed

    Wang, Ling; Yazici, Birsen

    2012-08-01

    We consider synthetic aperture radar (SAR) imaging using ultra-narrowband continuous waveforms (CW). Due to the high Doppler resolution of CW signals, we refer to this imaging modality as Doppler Synthetic Aperture Radar (DSAR). We present a novel model and an image formation method for the bistatic DSAR for arbitrary imaging geometries. Our bistatic DSAR model is formed by correlating the translated version of the received signal with a scaled or frequencyshifted version of the transmitted CW signal over a finite time window. High frequency analysis of the resulting model shows that the correlated signal is the projections of the scene reflectivity onto the bistatic iso-Doppler curves. We next use microlocal techniques to develop a filtered-backprojection (FBP) type image reconstruction method. The FBP inversion results in backprojection of the correlated signal onto the bistatic iso- Doppler curves as opposed to the bistatic iso-range curves, performed in the traditional wideband SAR imaging. We show that our method takes advantage of the velocity, as well as the acceleration of the antennas in certain directions to form a high resolution SAR image. Our bistatic DSAR imaging method is applicable for arbitrary flight trajectories, nonflat topography, and can accommodate system related parameters. We present resolution analysis and extensive numerical experiments to demonstrate the performance of our imaging method.

  9. Space Radar Image of Kilauea, Hawaii in 3-D

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a three-dimensional perspective view of a false-color image of the eastern part of the Big Island of Hawaii. It was produced using all three radar frequencies -- X-band, C-band and L-band -- from the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) flying on the space shuttle Endeavour, overlaid on a U.S. Geological Survey digital elevation map. Visible in the center of the image in blue are the summit crater (Kilauea Caldera) which contains the smaller Halemaumau Crater, and the line of collapse craters below them that form the Chain of Craters Road. The image was acquired on April 12, 1994 during orbit 52 of the space shuttle. The area shown is approximately 34 by 57 kilometers (21 by 35 miles) with the top of the image pointing toward northwest. The image is centered at about 155.25 degrees west longitude and 19.5 degrees north latitude. The false colors are created by displaying three radar channels of different frequency. Red areas correspond to high backscatter at L-HV polarization, while green areas exhibit high backscatter at C-HV polarization. Finally, blue shows high return at X-VV polarization. Using this color scheme, the rain forest appears bright on the image, while the green areas correspond to lower vegetation. The lava flows have different colors depending on their types and are easily recognizable due to their shapes. The flows at the top of the image originated from the Mauna Loa volcano. Kilauea volcano has been almost continuously active for more than the last 11 years. Field teams that were on the ground specifically to support these radar observations report that there was vigorous surface activity about 400 meters (one-quartermile) inland from the coast. A moving lava flow about 200 meters (650 feet) in length was observed at the time of the shuttle overflight, raising the possibility that subsequent images taken during this mission will show changes in the landscape. Currently, most of the lava that is

  10. Space Radar Image of Nile River Delta, Egypt

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image shows the area just north of the city of Cairo, Egypt, where the Nile River splits into two main branches. The Rosetta Branch is the curving dark line in the center of the image and the Damietta Branch is the curving dark line in the lower right of the image. The light blue area on the right half of the image is a portion of the Nile River Delta. The thinner, straighter lines and the small network of gold lines are irrigation canals. There are more than 10,000 kilometers of canals throughout the Nile Delta. A transition zone of irrigated fields is shown in blue and yellow between the irrigated delta and the surrounding desert. The desert is the dark blue area on the left side of the image lacking the pattern of irrigated fields. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on October 4, 1994, onboardthe space shuttle Endeavour. The image is 75 kilometers by 60 kilometers (46 miles by 37 miles) and is centered at 30.2 degreesnorth latitude, 31.1 degrees east longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontally transmitted and received; and blue is the ratio of C-band and L-band, horizontally transmitted and received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to PlanetEarth program.

  11. Space Radar Image of Craters of the Moon, Idaho

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Ancient lava flows dating back 2,000 to 15,000 years are shown in light green and red on the left side of this space radar image of the Craters of the Moon National Monument area in Idaho. The volcanic cones that produced these lava flows are the dark points shown within the light green area. Craters of the Moon National Monument is part of the Snake River Plain volcanic province. Geologists believe this area was formed as the North American tectonic plate moved across a 'hot spot' which now lies beneath Yellowstone National Park. The irregular patches, shown in red, green and purple in the lower half of the image are lava flows of different ages and surface roughnesses. One of these lava flows is surrounded by agricultural fields, the blue and purple geometric features, in the right center of the image. The town of Arco, Idaho is the bright yellow area on the right side of the agricultural area. The peaks along the top of the image are the White Knob Mountains. The Big Lost River flows out of the canyon at the top right of the image. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) when it flew aboard the space shuttle Endeavour on October 5, 1994. This image is centered at 43.58 degrees north latitude, 113.42 degrees west longitude. The area shown is approximately 33 kilometers by 48 kilometers 20.5 miles by 30 miles). Colors are assigned to different frequencies and polarizations of the radar as follows: red is the L-band horizontally transmitted, horizontally received; green is the L-band horizontally transmitted, vertically received; blue is the C-band horizontally transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  12. Space Radar Image of Mammoth, California in 3-D

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a three-dimensional perspective of Mammoth Mountain, California. This view was constructed by overlaying a Spaceborne Imaging Radar-C (SIR-C) radar image on a U.S. Geological Survey digital elevation map. Vertical exaggeration is 1.87 times. The image is centered at 37.6 degrees north, 119.0 degrees west. It was acquired from the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard space shuttle Endeavour on its 67th orbit on April 13, 1994. In this color representation, red is C-band HV-polarization, green is C-band VV-polarization and blue is the ratio of C-band VV to C-band HV. Blue areas are smooth, and yellow areas are rock out-crops with varying amounts of snow and vegetation. Crowley Lake is in the foreground, and Highway 395 crosses in the middle of the image. Mammoth Mountain is shown in the upper right. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI).

  13. Space Radar Image of Niya ruins, Taklamakan desert

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This radar image is of an area thought to contain the ruins of the ancient settlement of Niya. It is located in the southwestern corner of the Taklamakan Desert in China's Sinjiang Province. This oasis was part of the famous Silk Road, an ancient trade route from one of China's earliest capitols, Xian, to the West. The image shows a white linear feature trending diagonally from the upper left to the lower right. Scientists believe this newly discovered feature is a man-made canal which presumably diverted river waters toward the settlement of Niya for irrigation purposes. The image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 106th orbit on April 16, 1994, and is centered at 37.78 degrees north latitude and 82.41 degrees east longitude. The false-color radar image was created by displaying the C-band (horizontally transmitted and received) return in red, the L-band (horizontally transmitted and received) return in green, and the L-band (horizontally transmitted and vertically received) return in blue. Areas in mottled white and purple are low-lying floodplains of the Niya River. Dark green and black areas between river courses are higher ridges or dunes confining the water flow. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: the L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by

  14. Radar Image with Color as Height, Ancharn Kuy, Cambodia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of Ancharn Kuy, Cambodia, was taken by NASA's Airborne Synthetic Aperture Radar (AIRSAR). The image depicts an area northwest of Angkor Wat. The radar has highlighted a number of circular village mounds in this region, many of which have a circular pattern of rice fields surrounding the slightly elevated site. Most of them have evidence of what seems to be pre-Angkor occupation, such as stone tools and potsherds. Most of them also have a group of five spirit posts, a pattern not found in other parts of Cambodia. The shape of the mound, the location in the midst of a ring of rice fields, the stone tools and the current practice of spirit veneration have revealed themselves through a unique 'marriage' of radar imaging, archaeological investigation, and anthropology.

    Ancharn Kuy is a small village adjacent to the road, with just this combination of features. The region gets slowly higher in elevation, something seen in the shift of color from yellow to blue as you move to the top of the image.

    The small dark rectangles are typical of the smaller water control devices employed in this area. While many of these in the center of Angkor are linked to temples of the 9th to 14th Century A.D., we cannot be sure of the construction date of these small village tanks. They may pre-date the temple complex, or they may have just been dug ten years ago!

    The image dimensions are approximately 4.75 by 4.3 kilometers (3 by 2.7 miles) with a pixel spacing of 5 meters (16.4 feet). North is at top. Image brightness is from the C-band (5.6 centimeters, or 2.2 inches) wavelength radar backscatter, which is a measure of how much energy the surface reflects back toward the radar. Color is used to represent elevation contours. One cycle of color; that is going from blue to red to yellow to green and back to blue again; corresponds to 10 meters (32.8 feet) of elevation change.

    AIRSAR flies aboard a NASA DC-8 based at NASA's Dryden Flight Research Center, Edwards, Calif

  15. Design and prototype of radar sensor with Vivaldi linear array for through-wall radar imaging: an experimental study

    NASA Astrophysics Data System (ADS)

    Yılmaz, Betül; Özdemir, Caner

    2016-10-01

    We present a radar sensor that was designed to detect and image moving objects/targets on the other side of a wall. The radar sensor was composed of a linear array of Vivaldi antenna elements, an radio frequency (RF) switch, a microcontroller unit, and an RF transceiver. For the linear array, a total of eight antenna elements were used as sensors in synthetic aperture radar (SAR) configuration in the cross-range axis to improve the resolution in this dimension. Design steps of Vivaldi antenna elements and the entire linear array were presented. After the design, the prototyping procedure and the details of the radar sensor were given. Through-the-wall radar (TWR) imaging experiments were performed for stationary and moving targets using the assembled sensor. The resultant TWR images after these experiments were presented. During the image formation, a back-projection type image focusing algorithm was implemented and applied to increase the signal-to-noise ratio of the raw images. The constructed radar images demonstrated that our radar sensor could successfully detect and image both stationary and moving targets on the other side of the wall.

  16. Thermally Enhanced Photoacoustic Radar Imaging of Biotissues

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Mandelis, Andreas

    2015-06-01

    The signal-to-noise ratio (SNR) and imaging depth of photoacoustic (PA) imaging remain limited for clinical applications. The temperature can influence PA signals; the SNR of PA signals can be increased at higher temperatures. Therefore, the imaging quality and depth can be improved by the assistance of heating. Experimental results showed that the maximum imaging depth can be doubled by raising the temperature of the absorbers ( ex-vivo beef muscle) uniformly from to , and the SNR can be increased.

  17. Imaging of concrete specimens using inverse synthetic aperture radar

    NASA Astrophysics Data System (ADS)

    Rhim, Hong C.; Buyukozturk, Oral

    2000-05-01

    Radar Measurement results of laboratory size concrete specimens are presented in this paper. The purpose of this research work is to study various aspects of the radar method in an effort to develop an improved radar system for nondestructive testing of concrete structures. The radar system used for the study is an Inverse Synthetic Aperture Radar (ISAR), which is capable of transmitting microwaves at three different frequency ranges of 2-3.4, 3.4-5.8, and 8-12 GHz. Radar measurement setup is such that the radar is locates 14.4 m away from a concrete target to satisfy a far-field criterion. The concrete target is rotated for 20 degrees during the measurements for the generation of two-dimensional (cross-range) imagery. Concrete targets used for the measurements have the dimensions of 305 mm (width)×305 mm (height)×92 mm (thickness) with different inside configurations. Comparisons are made for dry and wet specimens, specimens with and without inclusions. Each specimen is made to model various situations that a concrete structure can have in reality. Results show that center frequency, frequency bandwidth, and polarization of the incident wave have different effects on identifying the thickness or inclusions inside concrete specimens. Results also suggest that a certain combination of measurement parameters is suitable for a specific application area. Thus, measurement parameters can be optimized for a specific problem. The findings are presented and discussed in details in the paper. Signal processing schemes implemented for imaging of the specimens are also discussed.

  18. New Orleans Topography, Radar Image with Colored Height

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for the animation

    About the animation: This simulated view of the potential effects of storm surge flooding on Lake Pontchartrain and the New Orleans area was generated with data from the Shuttle Radar Topography Mission. Although it is protected by levees and sea walls against storm surges of 18 to 20 feet, much of the city is below sea level, and flooding due to storm surges caused by major hurricanes is a concern. The animation shows regions that, if unprotected, would be inundated with water. The animation depicts flooding in one-meter increments.

    About the image: The city of New Orleans, situated on the southern shore of Lake Pontchartrain, is shown in this radar image from the Shuttle Radar Topography Mission (SRTM). In this image bright areas show regions of high radar reflectivity, such as from urban areas, and elevations have been coded in color using height data also from the SRTM mission. Dark green colors indicate low elevations, rising through yellow and tan, to white at the highest elevations.

    New Orleans is near the center of this scene, between the lake and the Mississippi River. The line spanning the lake is the Lake Pontchartrain Causeway, the world's longest overwater highway bridge. Major portions of the city of New Orleans are actually below sea level, and although it is protected by levees and sea walls that are designed to protect against storm surges of 18 to 20 feet, flooding during storm surges associated with major hurricanes is a significant concern.

    Data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface

  19. Space Radar Image of Calcutta, West Bengal, India

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This radar image of Calcutta, India, illustrates different urban land use patterns. Calcutta, the largest city in India, is located on the banks of the Hugli River, shown as the thick, dark line in the upper portion of the image. The surrounding area is a flat swampy region with a subtropical climate. As a result of this marshy environment, Calcutta is a compact city, concentrated along the fringes of the river. The average elevation is approximately 9 meters (30 feet) above sea level. Calcutta is located 154 kilometers (96 miles) upstream from the Bay of Bengal. Central Calcutta is the light blue and orange area below the river in the center of the image. The bridge spanning the river at the city center is the Howrah Bridge which links central Calcutta to Howrah. The dark region just below the river and to the left of the city center is Maidan, a large city park housing numerous cultural and recreational facilities. The international airport is in the lower right of the image. The bridge in the upper right is the Bally Bridge which links the suburbs of Bally and Baranagar. This image is 30 kilometers by 10 kilometers (19 miles by 6 miles)and is centered at 22.3 degrees north latitude, 88.2 degrees east longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is L-band, horizontally transmitted and vertically received; and blue is C-band, horizontally transmitted and vertically received. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on October 5, 1994, onboard the Space Shuttle Endeavour. SIR-C/X SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  20. MIMO-OFDM signal optimization for SAR imaging radar

    NASA Astrophysics Data System (ADS)

    Baudais, J.-Y.; Méric, S.; Riché, V.; Pottier, É.

    2016-12-01

    This paper investigates the optimization of the coded orthogonal frequency division multiplexing (OFDM) transmitted signal in a synthetic aperture radar (SAR) context. We propose to design OFDM signals to achieve range ambiguity mitigation. Indeed, range ambiguities are well known to be a limitation for SAR systems which operates with pulsed transmitted signal. The ambiguous reflected signal corresponding to one pulse is then detected when the radar has already transmitted the next pulse. In this paper, we demonstrate that the range ambiguity mitigation is possible by using orthogonal transmitted wave as OFDM pulses. The coded OFDM signal is optimized through genetic optimization procedures based on radar image quality parameters. Moreover, we propose to design a multiple-input multiple-output (MIMO) configuration to enhance the noise robustness of a radar system and this configuration is mainly efficient in the case of using orthogonal waves as OFDM pulses. The results we obtain show that OFDM signals outperform conventional radar chirps for range ambiguity suppression and for robustness enhancement in 2 ×2 MIMO configuration.

  1. Space Radar Image of Possible String of Impact Creaters

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The impact of an asteroid or comet several hundred million years ago left scars in the landscape that are still visible in this spaceborne radar image of an area in the Sahara Desert of northern Chad. The concentric ring structure left of center is the Aorounga impact crater with a diameter of about 17 kilometers (10.5 miles). Scientists are using radar images to investigate the possibility that Aorounga formed as part of a multiple impact event. A proposed second crater, similar in size to the main structure, appears as a circular trough surrounding a central peak in the center of the image. A third structure, also about the same size, is seen as a dark, partial circular trough with a possible central structure in the right center of the image. The proposed crater 'chain' could have formed when a 1 km to 2 km (0.5 mile to 1 mile) diameter object broke apart before impact. The dark streaks are deposits of windblown sand that migrate along valleys cut by thousands of years of wind erosion. Radar imaging is a valuable tool for the study of desert regions because the radar waves can penetrate thin layers of dry sand to reveal details of geologic structure that are invisible to other sensors. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on April 18 and 19, 1994, onboard the space shuttle Endeavour. The area shown is 45 kilometers by 61 kilometers (28 miles by 38 miles) and is centeredat 19.25 degrees north latitude, 19.25 degrees east longitude. North is toward the upper right. The colors are assigned to differentradar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontallytransmitted and received; and blue is C-band, horizontally transmitted,vertically received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  2. Space Radar Image of Namib Desert in Southern Namib

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a C-band, VV polarization radar image of the Namib desert in southern Namibia, near the coast of South West Africa. The image is centered at about 25 degrees South latitude, 15.5 degrees East longitude. This image was one of the first acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) when it was taken on orbit 4 from the shuttle Endeavour on April 9, 1994. The area shown is approximately 78 kilometers by 20 kilometers. The dominant features in the image are complex sand dune patterns formed by the prevailing winds in this part of the Namib desert. The Namib desert is an extremely dry area formed largely because of the influence of the cold Benguela ocean current that flows northward along the coast of Namibia. The bright areas at the bottom of the image are exposed outcrops of Precambrian rocks. This extremely barren area is a region rich in diamonds that through the centuries have washed down from the mountains. The town of Luderitz is located just to the south of the area shown. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Aumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia

  3. Hurricane Rita Track Radar Image with Topographic Overlay

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Animation

    About the animation: This simulated view of the potential effects of storm surge flooding on Galveston and portions of south Houston was generated with data from the Shuttle Radar Topography Mission. Although it is protected by a 17-foot sea wall against storm surges, flooding due to storm surges caused by major hurricanes remains a concern. The animation shows regions that, if unprotected, would be inundated with water. The animation depicts flooding in one-meter increments.

    About the image: The Gulf Coast from the Mississippi Delta through the Texas coast is shown in this satellite image from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) overlain with data from the Shuttle Radar Topography Mission (SRTM), and the predicted storm track for Hurricane Rita. The prediction from the National Weather Service was published Sept. 22 at 4 p.m. Central Time, and shows the expected track center in black with the lighter shaded area indicating the range of potential tracks the storm could take.

    Low-lying terrain along the coast has been highlighted using the SRTM elevation data, with areas within 15 feet of sea level shown in red, and within 30 feet in yellow. These areas are more at risk for flooding and the destructive effects of storm surge and high waves.

    Data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between

  4. Space Radar Image of Rabaul Volcano, New Guinea

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a radar image of the Rabaul volcano on the island of New Britain, Papua, New Guinea taken almost a month after its September 19, 1994, eruption that killed five people and covered the town of Rabaul and nearby villages with up to 75 centimeters (30 inches) of ash. More than 53,000 people have been displaced by the eruption. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 173rd orbit on October 11, 1994. This image is centered at 4.2 degrees south latitude and 152.2 degrees east longitude in the southwest Pacific Ocean. The area shown is approximately 21 kilometers by 25 kilometers (13 miles by 15.5 miles). North is toward the upper right. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted and vertically received); blue represents the C-band (horizontally transmitted and vertically received). Most of the Rabaul volcano is underwater and the caldera (crater) creates Blanche Bay, the semi-circular body of water that occupies most of the center of the image. Volcanic vents within the caldera are visible in the image and include Vulcan, on a peninsula on the west side of the bay, and Rabalanakaia and Tavurvur (the circular purple feature near the mouth of the bay) on the east side. Both Vulcan and Tavurvur were active during the 1994 eruption. Ash deposits appear red-orange on the image, and are most prominent on the south flanks of Vulcan and north and northwest of Tavurvur. A faint blue patch in the water in the center of the image is a large raft of floating pumice fragments that were ejected from Vulcan during the eruption and clog the inner bay. Visible on the east side of the bay are the grid-like patterns of the streets of Rabaul and an airstrip, which appears as a dark northwest-trending band at the right-center of

  5. Radar image processing for rock-type discrimination

    NASA Technical Reports Server (NTRS)

    Blom, R. G.; Daily, M.

    1982-01-01

    Image processing and enhancement techniques for improving the geologic utility of digital satellite radar images are reviewed. Preprocessing techniques such as mean and variance correction on a range or azimuth line by line basis to provide uniformly illuminated swaths, median value filtering for four-look imagery to eliminate speckle, and geometric rectification using a priori elevation data. Examples are presented of application of preprocessing methods to Seasat and Landsat data, and Seasat SAR imagery was coregistered with Landsat imagery to form composite scenes. A polynomial was developed to distort the radar picture to fit the Landsat image of a 90 x 90 km sq grid, using Landsat color ratios with Seasat intensities. Subsequent linear discrimination analysis was employed to discriminate rock types from known areas. Seasat additions to the Landsat data improved rock identification by 7%.

  6. Sparse radar imaging using 2D compressed sensing

    NASA Astrophysics Data System (ADS)

    Hou, Qingkai; Liu, Yang; Chen, Zengping; Su, Shaoying

    2014-10-01

    Radar imaging is an ill-posed linear inverse problem and compressed sensing (CS) has been proved to have tremendous potential in this field. This paper surveys the theory of radar imaging and a conclusion is drawn that the processing of ISAR imaging can be denoted mathematically as a problem of 2D sparse decomposition. Based on CS, we propose a novel measuring strategy for ISAR imaging radar and utilize random sub-sampling in both range and azimuth dimensions, which will reduce the amount of sampling data tremendously. In order to handle 2D reconstructing problem, the ordinary solution is converting the 2D problem into 1D by Kronecker product, which will increase the size of dictionary and computational cost sharply. In this paper, we introduce the 2D-SL0 algorithm into the reconstruction of imaging. It is proved that 2D-SL0 can achieve equivalent result as other 1D reconstructing methods, but the computational complexity and memory usage is reduced significantly. Moreover, we will state the results of simulating experiments and prove the effectiveness and feasibility of our method.

  7. Three Dimensional Inverse Synthetic Aperture Radar Imaging

    DTIC Science & Technology

    1995-12-01

    to upsample the projection data in order to get sufficient image quality. Working within these memory constraints, three-dimensional images were... metallic film on the windscreen in order to block reflections from the cockpit. Photographs and scale drawings of the model are shown in Figures 11 and...as well as spurious responses in the final image. Theoretically, sufficient resolution should have been available without upsampling the original data

  8. Space Radar Image of Santa Cruz Island, California

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This space radar image shows the rugged topography of Santa Cruz Island, part of the Channel Islands National Park in the Pacific Ocean off the coast of Santa Barbara and Ventura, Calif. Santa Cruz, the largest island of the national park, is host to hundreds of species of plants, animals and birds, at least eight of which are known nowhere else in the world. The island is bisected by the Santa Cruz Island fault, which appears as a prominent line running from the upper left to the lower right in this image. The fault is part of the Transverse Range fault system, which extends eastward from this area across Los Angeles to near Palm Springs, Calif. Color variations in this image are related to the different types of vegetation and soils at the surface. For example, grass-covered coastal lowlands appear gold, while chaparral and other scrub areas appear pink and blue. The image is 35 kilometers by 32 kilometers (22 miles by 20 miles) and is centered at 33.8 degrees north latitude, 119.6 degrees west longitude. North is toward upper right. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontally transmitted and received; and blue is C-band, horizontally transmitted and vertically received. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on October 10, 1994, onboard the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  9. Space Radar Image of Sakura-Jima Volcano, Japan

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The active volcano Sakura-Jima on the island of Kyushu, Japan is shown in the center of this radar image. The volcano occupies the peninsula in the center of Kagoshima Bay, which was formed by the explosion and collapse of an ancient predecessor of today's volcano. The volcano has been in near continuous eruption since 1955. Its explosions of ash and gas are closely monitored by local authorities due to the proximity of the city of Kagoshima across a narrow strait from the volcano's center, shown below and to the left of the central peninsula in this image. City residents have grown accustomed to clearing ash deposits from sidewalks, cars and buildings following Sakura-jima's eruptions. The volcano is one of 15 identified by scientists as potentially hazardous to local populations, as part of the international 'Decade Volcano' program. The image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on October 9, 1994. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. The image is centered at 31.6 degrees North latitude and 130.6 degrees East longitude. North is toward the upper left. The area shown measures 37.5 kilometers by 46.5 kilometers (23.3 miles by 28.8 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band vertically transmitted, vertically received; green is the average of L-band vertically transmitted, vertically received and C-band vertically transmitted, vertically received; blue is C-band vertically transmitted, vertically received.

  10. Impulse radar imaging system for concealed object detection

    NASA Astrophysics Data System (ADS)

    Podd, F. J. W.; David, M.; Iqbal, G.; Hussain, F.; Morris, D.; Osakue, E.; Yeow, Y.; Zahir, S.; Armitage, D. W.; Peyton, A. J.

    2013-10-01

    Electromagnetic systems for imaging concealed objects at checkpoints typically employ radiation at millimetre and terahertz frequencies. These systems have been shown to be effective and provide a sufficiently high resolution image. However there are difficulties and current electromagnetic systems have limitations particularly in accurately differentiating between threat and innocuous objects based on shape, surface emissivity or reflectivity, which are indicative parameters. In addition, water has a high absorption coefficient at millimetre wavelength and terahertz frequencies, which makes it more difficult for these frequencies to image through thick damp clothing. This paper considers the potential of using ultra wideband (UWB) in the low gigahertz range. The application of this frequency band to security screening appears to be a relatively new field. The business case for implementing the UWB system has been made financially viable by the recent availability of low-cost integrated circuits operating at these frequencies. Although designed for the communication sector, these devices can perform the required UWB radar measurements as well. This paper reports the implementation of a 2 to 5 GHz bandwidth linear array scanner. The paper describes the design and fabrication of transmitter and receiver antenna arrays whose individual elements are a type of antipodal Vivaldi antenna. The antenna's frequency and angular response were simulated in CST Microwave Studio and compared with laboratory measurements. The data pre-processing methods of background subtraction and deconvolution are implemented to improve the image quality. The background subtraction method uses a reference dataset to remove antenna crosstalk and room reflections from the dataset. The deconvolution method uses a Wiener filter to "sharpen" the returned echoes which improves the resolution of the reconstructed image. The filter uses an impulse response reference dataset and a signal

  11. Radar image and data fusion for natural hazards characterisation

    USGS Publications Warehouse

    Lu, Zhong; Dzurisin, Daniel; Jung, Hyung-Sup; Zhang, Jixian; Zhang, Yonghong

    2010-01-01

    Fusion of synthetic aperture radar (SAR) images through interferometric, polarimetric and tomographic processing provides an all - weather imaging capability to characterise and monitor various natural hazards. This article outlines interferometric synthetic aperture radar (InSAR) processing and products and their utility for natural hazards characterisation, provides an overview of the techniques and applications related to fusion of SAR/InSAR images with optical and other images and highlights the emerging SAR fusion technologies. In addition to providing precise land - surface digital elevation maps, SAR - derived imaging products can map millimetre - scale elevation changes driven by volcanic, seismic and hydrogeologic processes, by landslides and wildfires and other natural hazards. With products derived from the fusion of SAR and other images, scientists can monitor the progress of flooding, estimate water storage changes in wetlands for improved hydrological modelling predictions and assessments of future flood impacts and map vegetation structure on a global scale and monitor its changes due to such processes as fire, volcanic eruption and deforestation. With the availability of SAR images in near real - time from multiple satellites in the near future, the fusion of SAR images with other images and data is playing an increasingly important role in understanding and forecasting natural hazards.

  12. SRTM Radar Image with Color as Height: Kachchh, Gujarat, India

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image shows the area around the January 26, 2001, earthquake in western India, the deadliest in the country's history with some 20,000 fatalities. The epicenter of the magnitude 7.6 earthquake was just to the left of the center of the image. The Gulf of Kachchh (or Kutch) is the black area running from the lower left corner towards the center of the image. The city of Bhuj is in the yellow-toned area among the brown hills left of the image center and is the historical capital of the Kachchh region. Bhuj and many other towns and cities nearby were almost completely destroyed by the shaking of the earthquake. These hills reach up to 500 meters (1,500 feet) elevation. The city of Ahmedabad, capital of Gujarat state, is the radar-bright area next to the right side of the image. Several buildings in Ahmedabad were also destroyed by the earthquake. The dark blue areas around the center of the image and extending to the left side are low-lying salt flats called the Rann of Kachchh with the Little Rann just to the right of the image center. The bumpy area north of the Rann (green and yellow colors) is a large area of sand dunes in Pakistan. A branch of the Indus River used to flow through the area on the left side of this image, but it was diverted by a previous large earthquake that struck this area in 1819.

    The annotated version of the image includes a 'beachball' that shows the location and slip direction of the January 26, 2001, earthquake from the Harvard Quick CMT catalog: http://www.seismology.harvard.edu/CMTsearch.html. [figure removed for brevity, see original site]

    This image combines two types of data from the Shuttle Radar Topography Mission (SRTM). The image brightness corresponds to the strength of the radar signal reflected from the ground, while colors show the elevation as measured by SRTM. Colors range from blue at the lowest elevations to brown and white at the highest elevations. This image is a mosaic of four SRTM swaths.

    This image

  13. Speckle Reduction in Synthetic Aperture Radar Images

    DTIC Science & Technology

    1988-05-01

    Finally, multilooking must be incorporated in the SAR processor. Most of the techniques to be described below are applied to the processed image. 3.2...Associates for the processing of raw SAR data in a standard format into image data. ’ / - DSTO -- ALI32LURY POSTAL ADDRESS: Director, Surveillance Research...Introduction I 2-. Soeckle models 3. NOISE REDUCTION TECHNIQUES 5 3.1 Multilooking 5 3.2 Image domain filters 6 3.3 Additive noise reduction 7 3.4 Wiener

  14. Parametric analysis of an imaging radar for use as an imaging radar for use as an independent landing monitor

    NASA Technical Reports Server (NTRS)

    Bundick, W. T.

    1974-01-01

    The capabilities are analyzed of a real aperture, forward-looking imaging radar for use as an independent landing monitor, which will provide the pilot with an independent means of assessing the progress of an automatic landing during Category 3 operations. The analysis shows that adequate ground resolution and signal-to-noise ratio can be obtained to image a runway with grassy surroundings using a radar operating at 35 GHz in good weather and in most fog but that performance is severely degraded in moderate to heavy rain and wet snow. Weather effects on a 10 GHz imager are not serious, with the possible exception of very heavy rain, but the azimuthal resolution at 10 GHz is inadequate with antennas up to 2 m long.

  15. Multiregion level-set partitioning of synthetic aperture radar images.

    PubMed

    Ben Ayed, Ismail; Mitiche, Amar; Belhadj, Ziad

    2005-05-01

    The purpose of this study is to investigate Synthetic Aperture Radar (SAR) image segmentation into a given but arbitrary number of gamma homogeneous regions via active contours and level sets. The segmentation of SAR images is a difficult problem due to the presence of speckle which can be modeled as strong, multiplicative noise. The proposed algorithm consists of evolving simple closed planar curves within an explicit correspondence between the interiors of curves and regions of segmentation to minimize a criterion containing a term of conformity of data to a speckle model of noise and a term of regularization. Results are shown on both synthetic and real images.

  16. A comparison of spotlight synthetic aperture radar image formation techniques

    SciTech Connect

    Knittle, C.D.; Doren, N.E.; Jakowatz, C.V.

    1996-10-01

    Spotlight synthetic aperture radar images can be formed from the complex phase history data using two main techniques: (1) polar-to-cartesian interpolation followed by two-dimensional inverse Fourier transform (2DFFT), and (2) convolution backprojection (CBP). CBP has been widely used to reconstruct medical images in computer aided tomography, and only recently has been applied to form synthetic aperture radar imagery. It is alleged that CBP yields higher quality images because (1) all the Fourier data are used and (2) the polar formatted data is used directly to form a 2D Cartesian image and therefore 2D interpolation is not required. This report compares the quality of images formed by CBP and several modified versions of the 2DFFT method. We show from an image quality point of view that CBP is equivalent to first windowing the phase history data and then interpolating to an exscribed rectangle. From a mathematical perspective, we should expect this conclusion since the same Fourier data are used to form the SAR image. We next address the issue of parallel implementation of each algorithm. We dispute previous claims that CBP is more readily parallelizable than the 2DFFT method. Our conclusions are supported by comparing execution times between massively parallel implementations of both algorithms, showing that both experience similar decreases in computation time, but that CBP takes significantly longer to form an image.

  17. Space Radar Image of the Lost City of Ubar

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a radar image of the region around the site of the lost city of Ubar in southern Oman, on the Arabian Peninsula. The ancient city was discovered in 1992 with the aid of remote sensing data. Archeologists believe Ubar existed from about 2800 B.C. to about 300 A.D. and was a remote desert outpost where caravans were assembled for the transport of frankincense across the desert. This image was acquired on orbit 65 of space shuttle Endeavour on April 13, 1994 by the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR). The SIR-C image shown is centered at 18.4 degrees north latitude and 53.6 degrees east longitude. The image covers an area about 50 by 100 kilometers (31 miles by 62 miles). The image is constructed from three of the available SIR-C channels and displays L-band, HH (horizontal transmit and receive) data as red, C-band HH as blue, and L-band HV (horizontal transmit, vertical receive) as green. The prominent magenta colored area is a region of large sand dunes, which are bright reflectors at both L-and C-band. The prominent green areas (L-HV) are rough limestone rocks, which form a rocky desert floor. A major wadi, or dry stream bed, runs across the middle of the image and is shown largely in white due to strong radar scattering in all channels displayed (L and C HH, L-HV). The actual site of the fortress of the lost city of Ubar, currently under excavation, is near the Wadi close to the center of the image. The fortress is too small to be detected in this image. However, tracks leading to the site, and surrounding tracks, appear as prominent, but diffuse, reddish streaks. These tracks have been used in modern times, but field investigations show many of these tracks were in use in ancient times as well. Mapping of these tracks on regional remote sensing images was a key to recognizing the site as Ubar in 1992. This image, and ongoing field investigations, will help shed light on a little known early civilization. Spaceborne

  18. Space Radar Image of Missouri River, Glasgow, Missouri

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a false-color L-band image of an area near Glasgow, Missouri, centered at about 39.2 degrees north latitude and 92.8 degrees west longitude. The image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 50th orbit on October 3, 1994. The false-color composite was made by displaying the L-band (horizontally transmitted and received) return in red; the L-band (horizontally transmitted and vertically received) return in green; and the sum of the two channels in blue. The area shown is approximately 37 kilometers by 25 kilometers (23 miles by 16 miles). The radar data, coupled with pre-flood aerial photography and satellite data and post-flood topographic and field data, are being used to evaluate changes associated with levee breaks in landforms, where deposits formed during the widespread flooding in 1993 along the Missouri and Mississippi Rivers. The distinct radar scattering properties of farmland, sand fields and scoured areas will be used to inventory floodplains along the Missouri River and determine the processes by which these areas return to preflood conditions. The image shows one such levee break near Glasgow, Missouri. In the upper center of the radar image is a region covered by several meters of sand, shown as blue regions below the bend in the river. West (left) of this dark area, a blue gap in the levee tree canopy can be seen, showing the area where the levee failed. Radar data such as these can help scientists more accurately assess the potential for future flooding in this region and how that might impact surrounding communities. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar(SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm

  19. Multi-sensor image interpretation using laser radar and thermal images

    NASA Astrophysics Data System (ADS)

    Chu, Chen-Chau; Aggarwal, J. K.

    1991-03-01

    A knowledge based system is presented which interprets registered laser radar and thermal images. The object is to detect and recognize man-made objects at kilometer range in outdoor scenes. The multisensor fusion approach is applied to various sensing modalities (range, intensity, velocity, and thermal) to improve both image segmentation and interpretation. The ability to use multiple sensors greatly helps an intelligent platform to understand and interact with its environment. The knowledge-based interpretation system, AIMS, is constructed using KEE and Lisp. Low-level attributes of image segments (regions) are computed by the segmentation modules and then converted into the KEE format. The interpretation system applies forward chaining in a bottom-up fashion to derive object-level interpretations from data bases generated by low-level processing modules. Segments are grouped into objects and then objects are classified into predefined categories. AIMS employs a two tiered software structure. The efficiency of AIMS is enhanced by transferring nonsymbolic processing tasks to a concurrent service manager (program). Therefore, tasks with different characteristics are executed using different software tools and methodologies.

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

    NASA Technical Reports Server (NTRS)

    Arens, W. E. (Inventor)

    1977-01-01

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

  1. On the automatic classification of rain patterns on radar images

    NASA Astrophysics Data System (ADS)

    Pawlina Bonati, Apolonia

    The automation of the process of identification and classification of rain patterns on radar derived images is approached using some tools of digital image interpretation adapted to the specific application. The formal characterization of rain patterns and their partition in classes related to the type of precipitation is the main problem addressed in the paper, as the standard well established criteria for such classification are not defined. The digital maps of rain at horizontal plane derived from three-dimensional radar scans are processed by the interpretation package which identifies and classifies rain structures present on the map. The results generated by this package are illustrated in the paper and offered for discussion. The interpretation procedure is tailored for the radio-meteorology applications but the method is adaptable to other field requirements.

  2. Synthetic aperture radar/LANDSAT MSS image registration

    NASA Technical Reports Server (NTRS)

    Maurer, H. E. (Editor); Oberholtzer, J. D. (Editor); Anuta, P. E. (Editor)

    1979-01-01

    Algorithms and procedures necessary to merge aircraft synthetic aperture radar (SAR) and LANDSAT multispectral scanner (MSS) imagery were determined. The design of a SAR/LANDSAT data merging system was developed. Aircraft SAR images were registered to the corresponding LANDSAT MSS scenes and were the subject of experimental investigations. Results indicate that the registration of SAR imagery with LANDSAT MSS imagery is feasible from a technical viewpoint, and useful from an information-content viewpoint.

  3. Forest discrimination with multipolarization imaging radar

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    The relations between polarization signatures and biophysical characteristics through a range of different forest environments were investigated using airborne synthetic-aperture (SAR) images acquired at L-band on March 1, 1984 in South Carolina. SAR data acquired in four linear polarization states with 10-m spatial resolution were encoded as color composite images and compared to US Forest Service forest stand data. The most useful correlative forest data were stand basal area, forest age, site condition index, and forest management type. It is found that the multipolarization images discriminate variation in tree density or difference in the amount of understory, but no evidence has been found for discrimination between evergreen and deciduous forest types.

  4. Airborne Microwave Imaging of River Velocities

    NASA Technical Reports Server (NTRS)

    Plant, William J.

    2002-01-01

    The objective of this project was to determine whether airborne microwave remote sensing systems can measure river surface currents with sufficient accuracy to make them prospective instruments with which to monitor river flow from space. The approach was to fly a coherent airborne microwave Doppler radar, developed by APL/UW, on a light airplane along several rivers in western Washington state over an extended period of time. The fundamental quantity obtained by this system to measure river currents is the mean offset of the Doppler spectrum. Since this scatter can be obtained from interferometric synthetic aperture radars (INSARs), which can be flown in space, this project provided a cost effective means for determining the suitability of spaceborne INSAR for measuring river flow.

  5. Semisupervised synthetic aperture radar image segmentation with multilayer superpixels

    NASA Astrophysics Data System (ADS)

    Wang, Can; Su, Weimin; Gu, Hong; Gong, Dachen

    2015-01-01

    Image segmentation plays a significant role in synthetic aperture radar (SAR) image processing. However, SAR image segmentation is challenging due to speckle. We propose a semisupervised bipartite graph method for segmentation of an SAR image. First, the multilayer over-segmentation of the SAR image, referred to as superpixels, is computed using existing segmentation algorithms. Second, an unbalanced bipartite graph is constructed in which the correlation between pixels is replaced by the texture similarity between superpixels, to reduce the dimension of the edge matrix. To also improve efficiency, we define a new method, called the combination of the Manhattan distance and symmetric Kullback-Leibler divergence, to measure texture similarity. Third, by the Moore-Penrose inverse matrix and semisupervised learning, we construct an across-affinity matrix. A quantitative evaluation using SAR images shows that the new algorithm produces significantly high-quality segmentations as compared with state-of-the-art segmentation algorithms.

  6. Mapping diverse vegetation with multichannel radar images

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    Airborne-SAR, SIR-A, Seasat SAR, and Landsat TM images of the Savannah River Plant, a gently sloping area of South Carolina covered with diverse vegetation, are presented and briefly characterized. Preliminary results indicate that multiple-polarization images constructed from the airborne-SAR data give some indication of forest density and understory growth but do not permit discrimination between evergreen and deciduous forests. Heat-tolerant vegetation growing on sand bars in streams bearing thermal effluents from nuclear reactors on the site is found to have a distinguishing polarization signature.

  7. Space Radar Image of the Yucatan Impact Crater Site

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a radar image of the southwest portion of the buried Chicxulub impact crater in the Yucatan Peninsula, Mexico. The radar image was acquired on orbit 81 of space shuttle Endeavour on April 14, 1994 by the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR). The image is centered at 20 degrees north latitude and 90 degrees west longitude. Scientists believe the crater was formed by an asteroid or comet which slammed into the Earth more than 65 million years ago. It is this impact crater that has been linked to a major biological catastrophe where more than 50 percent of the Earth's species, including the dinosaurs, became extinct. The 180-to 300-kilometer-diameter (110- to 180-mile)crater is buried by 300 to 1,000 meters (1,000 to 3,000 feet) of limestone. The exact size of the crater is currently being debated by scientists. This is a total power radar image with L-band in red, C-band in green, and the difference between C-band L-band in blue. The 10-kilometer-wide (6-mile) band of yellow and pink with blue patches along the top left (northwestern side) of the image is a mangrove swamp. The blue patches are islands of tropical forests created by freshwater springs that emerge through fractures in the limestone bedrock and are most abundant in the vicinity of the buried crater rim. The fracture patterns and wetland hydrology in this region are controlled by the structure of the buried crater. Scientists are using the SIR-C/X-SAR imagery to study wetland ecology and help determine the exact size of the impact crater. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community

  8. High Resolution 3D Radar Imaging of Comet Interiors

    NASA Astrophysics Data System (ADS)

    Asphaug, E. I.; Gim, Y.; Belton, M.; Brophy, J.; Weissman, P. R.; Heggy, E.

    2012-12-01

    Knowing the interiors of comets and other primitive bodies is fundamental to our understanding of how planets formed. We have developed a Discovery-class mission formulation, Comet Radar Explorer (CORE), based on the use of previously flown planetary radar sounding techniques, with the goal of obtaining high resolution 3D images of the interior of a small primitive body. We focus on the Jupiter-Family Comets (JFCs) as these are among the most primitive bodies reachable by spacecraft. Scattered in from far beyond Neptune, they are ultimate targets of a cryogenic sample return mission according to the Decadal Survey. Other suitable targets include primitive NEOs, Main Belt Comets, and Jupiter Trojans. The approach is optimal for small icy bodies ~3-20 km diameter with spin periods faster than about 12 hours, since (a) navigation is relatively easy, (b) radar penetration is global for decameter wavelengths, and (c) repeated overlapping ground tracks are obtained. The science mission can be as short as ~1 month for a fast-rotating JFC. Bodies smaller than ~1 km can be globally imaged, but the navigation solutions are less accurate and the relative resolution is coarse. Larger comets are more interesting, but radar signal is unlikely to be reflected from depths greater than ~10 km. So, JFCs are excellent targets for a variety of reasons. We furthermore focus on the use of Solar Electric Propulsion (SEP) to rendezvous shortly after the comet's perihelion. This approach leaves us with ample power for science operations under dormant conditions beyond ~2-3 AU. This leads to a natural mission approach of distant observation, followed by closer inspection, terminated by a dedicated radar mapping orbit. Radar reflections are obtained from a polar orbit about the icy nucleus, which spins underneath. Echoes are obtained from a sounder operating at dual frequencies 5 and 15 MHz, with 1 and 10 MHz bandwidths respectively. The dense network of echoes is used to obtain global 3D

  9. Space Radar Image of Central African Gorilla Habitat

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a false-color radar image of Central Africa, showing the Virunga Volcano chain along the borders of Rwanda, Zaire and Uganda. This area is home to the endangered mountain gorillas. This C-band L-band image was acquired on April 12, 1994, on orbit 58 of space shuttle Endeavour by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR). The area is centered at about 1.75 degrees south latitude and 29.5 degrees east longitude. The image covers an area 58 kilometers by 178 kilometers (48 miles by 178 miles). The false-color composite is created by displaying the L-band HH return in red, the L-band HV return in green and the C-band HH return in blue. The dark area in the bottom of the image is Lake Kivu, which forms the border between Zaire (to the left) and Rwanda (to the right). The airport at Goma, Zaire is shown as a dark line just above the lake in the bottom left corner of the image. Volcanic flows from the 1977 eruption of Mt. Nyiragongo are shown just north of the airport. Mt. Nyiragongo is not visible in this image because it is located just to the left of the image swath. Very fluid lava flows from the 1977 eruption killed 70 people. Mt. Nyiragongo is currently erupting (August 1994) and will be a target of observation during the second flight of SIR-C/X-SAR. The large volcano in the center of the image is Mt. Karisimbi (4,500 meters or 14,800 feet). This radar image highlights subtle differences in the vegetation and volcanic flows of the region. The faint lines shown in the purple regions are believed to be the result of agriculture terracing by the people who live in the region. The vegetation types are an important factor in the habitat of the endangered mountain gorillas. Researchers at Rutgers University in New Jersey and the Dian Fossey Gorilla Fund in London will use this data to produce vegetation maps of the area to aid in their study of the remaining 650 gorillas in the region. SIR-C was developed by NASA's Jet

  10. Space Radar Image of Salt Lake City, Utah

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This radar image of Salt Lake City, Utah, illustrates the different land use patterns that are present in the Utah Valley. Salt Lake City lies between the shores of the Great Salt Lake (the dark area on the left side of the image) and the Wasatch Front Range (the mountains in the upper half of the image). The Salt Lake City area is of great interest to urban planners because of the combination of lake, valley and alpine environments that coexist in the region. Much of the southern shore of the Great Salt Lake is a waterfowl management area. The green grid pattern in the right center of the image is Salt Lake City and its surrounding communities. The Salt Lake City airport is visible as the brown rectangle near the center of the image. Interstate Highway 15 runs from the middle right edge to the upper left of the image. The bright white patch east of Interstate 15 is the downtown area, including Temple Square and the state capitol. The University of Utah campus is the yellowish area that lies at the base of the mountains, east of Temple Square. The large reservoir in the lower left center is a mine tailings pond. The semi-circular feature in the mountains at the bottom edge of the image is the Kennecott Copper Mine. The area shown is 60 kilometers by 40 kilometers (37 miles by 25 miles) and is centered at 40.6 degrees north latitude, 112.0 degrees west longitude. North is toward the upper left. This image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on April 10, 1994. The colors in this image represent the following radar channels and polarizations: red is L-band, horizontally transmitted and received; green is L-band, horizontally transmitted and vertically received; and blue is C-band, horizontally transmitted and vertically received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

  11. Three-dimensional radar imaging techniques and systems for near-field applications

    SciTech Connect

    Sheen, David M.; Hall, Thomas E.; McMakin, Douglas L.; Jones, Anthony M.; Tedeschi, Jonathan R.

    2016-05-12

    The Pacific Northwest National Laboratory has developed three-dimensional holographic (synthetic aperture) radar imaging techniques and systems for a wide variety of near-field applications. These applications include radar cross-section (RCS) imaging, personnel screening, standoff concealed weapon detection, concealed threat detection, through-barrier imaging, ground penetrating radar (GPR), and non-destructive evaluation (NDE). Sequentially-switched linear arrays are used for many of these systems to enable high-speed data acquisition and 3-D imaging. In this paper, the techniques and systems will be described along with imaging results that demonstrate the utility of near-field 3-D radar imaging for these compelling applications.

  12. Three-dimensional radar imaging techniques and systems for near-field applications

    NASA Astrophysics Data System (ADS)

    Sheen, David M.; Hall, Thomas E.; McMakin, Douglas L.; Jones, A. Mark; Tedeschi, Jonathan R.

    2016-05-01

    The Pacific Northwest National Laboratory has developed three-dimensional holographic (synthetic aperture) radar imaging techniques and systems for a wide variety of near-field applications. These applications include radar crosssection (RCS) imaging, personnel screening, standoff concealed weapon detection, concealed threat detection, throughbarrier imaging, ground penetrating radar (GPR), and non-destructive evaluation (NDE). Sequentially-switched linear arrays are used for many of these systems to enable high-speed data acquisition and 3-D imaging. In this paper, the techniques and systems will be described along with imaging results that demonstrate the utility of near-field 3-D radar imaging for these compelling applications.

  13. Space Radar Image of Colima Volcano, Jalisco, Mexico

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an image of the Colima volcano in Jalisco, Mexico, a vigorously active volcano that erupted as recently as July 1994. The eruption partially destroyed a lava dome at the summit and deposited a new layer of ash on the volcano's southern slopes. Surrounding communities face a continuing threat of ash falls and volcanic mudflows from the volcano, which has been designated one of 15 high-risk volcanoes for scientific study during the next decade. This image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 24th orbit on October 1, 1994. The image is centered at 19.4 degrees north latitude, 103.7 degrees west longitude. The area shown is approximately 35.7 kilometers by 37.5 kilometers (22 miles by 23 miles). This single-frequency, multi-polarized SIR-C image shows: red as L-band horizontally transmitted and received; green as L-band horizontally transmitted and vertically received; and blue as the ratio of the two channels. The summit area appears orange and the recent deposits fill the valleys along the south and southwest slopes. Observations from space are helping scientists understand the behavior of dangerous volcanoes and will be used to mitigate the effects of future eruptions on surrounding populations. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: the L-band (24 cm), the C-band (6 cm) and the X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature

  14. Radar Image with Color as Height, Old Khmer Road, Cambodia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image shows the Old Khmer Road (Inrdratataka-Bakheng causeway) in Cambodia extending from the 9th Century A.D. capitol city of Hariharalaya in the lower right portion of the image to the later 10th Century AD capital of Yasodharapura. This was located in the vicinity of Phnom Bakheng (not shown in image). The Old Road is believed to be more than 1000 years old. Its precise role and destination within the 'new' city at Angkor is still being studied by archeologists. But wherever it ended, it not only offered an immense processional way for the King to move between old and new capitols, it also linked the two areas, widening the territorial base of the Khmer King. Finally, in the past and today, the Old Road managed the waters of the floodplain. It acted as a long barrage or dam for not only the natural streams of the area but also for the changes brought to the local hydrology by Khmer population growth.

    The image was acquired by NASA's Airborne Synthetic Aperture Radar (AIRSAR). Image brightness is from the P-band (68 cm wavelength) radar backscatter, which is a measure of how much energy the surface reflects back towards the radar. Color is used to represent elevation contours. One cycle of color represents 20 m of elevation change, that is going from blue to red to yellow to green and back to blue again corresponds to 20 m of elevation change. Image dimensions are approximately 3.4 km by 3.5 km with a pixel spacing of 5 m. North is at top.

    AIRSAR flies aboard a NASA DC-8 based at NASA's Dryden Flight Research Center, Edwards, Calif. In the TOPSAR mode, AIRSAR collects radar interferometry data from two spatially separated antennas (2.6 meters, or 8.5 feet). Information from the two antennas is used to form radar backscatter imagery and to generate highly accurate elevation data. Built, operated and managed by JPL, AIRSAR is part of NASA's Earth Science Enterprise program. JPL is a division of the California Institute of Technology in Pasadena.

  15. Space Radar Image of Karakax Valley, China 3-D

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This three-dimensional perspective of the remote Karakax Valley in the northern Tibetan Plateau of western China was created by combining two spaceborne radar images using a technique known as interferometry. Visualizations like this are helpful to scientists because they reveal where the slopes of the valley are cut by erosion, as well as the accumulations of gravel deposits at the base of the mountains. These gravel deposits, called alluvial fans, are a common landform in desert regions that scientists are mapping in order to learn more about Earth's past climate changes. Higher up the valley side is a clear break in the slope, running straight, just below the ridge line. This is the trace of the Altyn Tagh fault, which is much longer than California's San Andreas fault. Geophysicists are studying this fault for clues it may be able to give them about large faults. Elevations range from 4000 m (13,100 ft) in the valley to over 6000 m (19,700 ft) at the peaks of the glaciated Kun Lun mountains running from the front right towards the back. Scale varies in this perspective view, but the area is about 20 km (12 miles) wide in the middle of the image, and there is no vertical exaggeration. The two radar images were acquired on separate days during the second flight of the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour in October 1994. The interferometry technique provides elevation measurements of all points in the scene. The resulting digital topographic map was used to create this view, looking northwest from high over the valley. Variations in the colors can be related to gravel, sand and rock outcrops. This image is centered at 36.1 degrees north latitude, 79.2 degrees east longitude. Radar image data are draped over the topography to provide the color with the following assignments: Red is L-band vertically transmitted, vertically received; green is the average of L-band vertically transmitted

  16. Space Radar Image of Mount Pinatubo Volcano, Philippines

    NASA Technical Reports Server (NTRS)

    1994-01-01

    These are color composite radar images showing the area around Mount Pinatubo in the Philippines. The images were acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on April 14, 1994 (left image) and October 5,1994 (right image). The images are centered at about 15 degrees north latitude and 120.5 degrees east longitude. Both images were obtained with the same viewing geometry. The color composites were made by displaying the L-band (horizontally transmitted and received) in red; the L-band (horizontally transmitted and vertically received) in green; and the C-band (horizontally transmitted and vertically received) in blue. The area shown is approximately 40 kilometers by 65 kilometers (25 miles by 40 miles). The main volcanic crater on Mount Pinatubo produced by the June 1991 eruptions and the steep slopes on the upper flanks of the volcano are easily seen in these images. Red on the high slopes shows the distribution of the ash deposited during the 1991 eruption, which appears red because of the low cross-polarized radar returns at C and L bands. The dark drainages radiating away from the summit are the smooth mudflows, which even three years after the eruptions continue to flood the river valleys after heavy rain. Comparing the two images shows that significant changes have occurred in the intervening five months along the Pasig-Potrero rivers (the dark area in the lower right of the images). Mudflows, called 'lahars,' that occurred during the 1994 monsoon season filled the river valleys, allowing the lahars to spread over the surrounding countryside. Three weeks before the second image was obtained, devastating lahars more than doubled the area affected in the Pasig-Potrero rivers, which is clearly visible as the increase in dark area on the lower right of the images. Migration of deposition to the east (right) has affected many communities. Newly affected areas included the community

  17. Large-scale Observations of a Subauroral Polarization Stream by Midlatitude SuperDARN Radars: Instantaneous Longitudinal Velocity Variations

    NASA Technical Reports Server (NTRS)

    Clausen, L. B. N.; Baker, J. B. H.; Sazykin, S.; Ruohoniemi, J. M.; Greenwald, R. A.; Thomas, E. J.; Shepherd, S. G.; Talaat, E. R.; Bristow, W. A.; Zheng, Y.; Coster, A. J.

    2012-01-01

    We present simultaneous measurements of flow velocities inside a subauroral polarization stream (SAPS) made by six midlatitude high-frequency SuperDARN radars. The instantaneous observations cover three hours of universal time and six hours of magnetic local time (MLT). From velocity variations across the field-of-view of the radars we infer the local 2D flow direction at three different longitudes. We find that the local flow direction inside the SAPS channel is remarkably constant over the course of the event. The flow speed, however, shows significant temporal and spatial variations. After correcting for the radar look direction we are able to accurately determine the dependence of the SAPS velocity on magnetic local time. We find that the SAPS velocity variation with magnetic local time is best described by an exponential function. The average velocity at 00 MLT was 1.2 km/s and it decreased with a spatial e-folding scale of two hours of MLT toward the dawn sector. We speculate that the longitudinal distribution of pressure gradients in the ring current is responsible for this dependence and find these observations in good agreement with results from ring current models. Using TEC measurements we find that the high westward velocities of the SAPS are - as expected - located in a region of low TEC values, indicating low ionospheric conductivities.

  18. Validation of the Electromagnetic Code FACETS for Numerical Simulation of Radar Target Images

    DTIC Science & Technology

    2009-12-01

    In particular, radar target images in the X -band region around 10 GHz are of considerable interest; most military maritime and air-borne radar systems...image simulation of targets in the X -band radar frequency. This numerical method permits computation of a complex-target image to be done within a...reasonable amount of computational time. Measured X -band image data of a canonical target known as SLICY (Sandia Laboratory Implementation of Cylinders

  19. Space Radar Image of Kennedy Space Center, Florida

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is an X-band Synthetic Aperture Radar image spanning an area of about 20 kilometers by 40 kilometers (12 miles by 25 miles) of the Kennedy Space Center, Florida. At the top right are cloud-like structures which indicate rain. X-SAR is able to image heavy rainfall. The Atlantic Ocean is at the upper right. The shuttle landing strip is seen at the top left of the image. The Vertical Assembly Building, the Orbiter Processing Facility and other associated buildings are seen as a white area to the right and just above the end of the shuttle strip. The shuttle launch pads are the two white areas near the top center of the image. The Banana River shows up as a large black area running north to south to the right of the image. The Indian River is on the left side of the image. Just above the image center is a cluster of white spots which are the major buildings of the Kennedy Space Center industrial area. This was the location of the reflector array that was constructed to form the letters 'KSC' by the KSC payload team. The data for these KSC images were taken on orbit 81 of the space shuttle Endeavour on the fourth day of the SIR-C/X-SAR mission. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio

  20. Radar Image with Color as Height, Sman Teng, Temple, Cambodia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of Cambodia's Angkor region, taken by NASA's Airborne Synthetic Aperture Radar (AIRSAR), reveals a temple (upper-right) not depicted on early 19th Century French archeological survey maps and American topographic maps. The temple, known as 'Sman Teng,' was known to the local Khmer people, but had remained unknown to historians due to the remoteness of its location. The temple is thought to date to the 11th Century: the heyday of Angkor. It is an important indicator of the strategic and natural resource contributions of the area northwest of the capitol, to the urban center of Angkor. Sman Teng, the name designating one of the many types of rice enjoyed by the Khmer, was 'discovered' by a scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., working in collaboration with an archaeological expert on the Angkor region. Analysis of this remote area was a true collaboration of archaeology and technology. Locating the temple of Sman Teng required the skills of scientists trained to spot the types of topographic anomalies that only radar can reveal.

    This image, with a pixel spacing of 5 meters (16.4 feet), depicts an area of approximately 5 by 4.7 kilometers (3.1 by 2.9 miles). North is at top. Image brightness is from the P-band (68 centimeters, or 26.8 inches) wavelength radar backscatter, a measure of how much energy the surface reflects back toward the radar. Color is used to represent elevation contours. One cycle of color represents 25 meters (82 feet) of elevation change, so going from blue to red to yellow to green and back to blue again corresponds to 25 meters (82 feet) of elevation change.

    AIRSAR flies aboard a NASA DC-8 based at NASA's Dryden Flight Research Center, Edwards, Calif. In the TOPSAR mode, AIRSAR collects radar interferometry data from two spatially separated antennas (2.6 meters, or 8.5 feet). Information from the two antennas is used to form radar backscatter imagery and to generate highly accurate elevation data

  1. Radar Image with Color as Height, Nokor Pheas Trapeng, Cambodia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Nokor Pheas Trapeng is the name of the large black rectangular feature in the center-bottom of this image, acquired by NASA's Airborne Synthetic Aperture Radar (AIRSAR). Its Khmer name translates as 'Tank of the City of Refuge'. The immense tank is a typical structure built by the Khmer for water storage and control, but its size is unusually large. This suggests, as does 'city' in its name, that in ancient times this area was far more prosperous than today.

    A visit to this remote, inaccessible site was made in December 1998. The huge water tank was hardly visible. From the radar data we knew that the tank stretched some 500 meters (1,640 feet) from east to west. However, between all the plants growing on the surface of the water and the trees and other vegetation in the area, the water tank blended with the surrounding topography. Among the vegetation, on the northeast of the tank, were remains of an ancient temple and a spirit shrine. So although far from the temples of Angkor, to the southeast, the ancient water structure is still venerated by the local people.

    The image covers an area approximately 9.5 by 8.7 kilometers (5.9 by 5.4 miles) with a pixel spacing of 5 meters (16.4 feet). North is at top. Image brightness is from the C-band (5.6 centimeters, or 2.2 inches) wavelength radar backscatter, which is a measure of how much energy the surface reflects back toward the radar. Color is used to represent elevation contours. One cycle of color represents 20 meters (65.6 feet) of elevation change; that is, going from blue to red to yellow to green and back to blue again corresponds to 20 meters (65.6 feet) of elevation change.

    AIRSAR flies aboard a NASA DC-8 based at NASA's Dryden Flight Research Center, Edwards, Calif. In the TOPSAR mode, AIRSAR collects radar interferometry data from two spatially separated antennas (2.6 meters, or 8.5 feet). Information from the two antennas is used to form radar backscatter imagery and to generate highly accurate

  2. Spaceborne bistatic synthetic aperture imaging radar

    NASA Technical Reports Server (NTRS)

    Elachi, C.; Goldstein, R.; Held, D.

    1981-01-01

    The properties of two configurations for a spaceborne bistatic SAR are examined and compared with the properties of a monostatic SAR. The two bistatic configurations considered are a system consisting of an orbiting spaceborne transmitter and a ground receiver and a system consisting of a transmitter on a geostationary satellite and a receiver or receivers on an airborne platform. The properties discussed or analyzed include imaging coordinate system, azimuth and range resolution, azimuth and range ambiguities, and swath width.

  3. Real-time windowing in imaging radar using FPGA technique

    NASA Astrophysics Data System (ADS)

    Ponomaryov, Volodymyr I.; Escamilla-Hernandez, Enrique

    2005-02-01

    The imaging radar uses the high frequency electromagnetic waves reflected from different objects for estimating of its parameters. Pulse compression is a standard signal processing technique used to minimize the peak transmission power and to maximize SNR, and to get a better resolution. Usually the pulse compression can be achieved using a matched filter. The level of the side-lobes in the imaging radar can be reduced using the special weighting function processing. There are very known different weighting functions: Hamming, Hanning, Blackman, Chebyshev, Blackman-Harris, Kaiser-Bessel, etc., widely used in the signal processing applications. Field Programmable Gate Arrays (FPGAs) offers great benefits like instantaneous implementation, dynamic reconfiguration, design, and field programmability. This reconfiguration makes FPGAs a better solution over custom-made integrated circuits. This work aims at demonstrating a reasonably flexible implementation of FM-linear signal and pulse compression using Matlab, Simulink, and System Generator. Employing FPGA and mentioned software we have proposed the pulse compression design on FPGA using classical and novel windows technique to reduce the side-lobes level. This permits increasing the detection ability of the small or nearly placed targets in imaging radar. The advantage of FPGA that can do parallelism in real time processing permits to realize the proposed algorithms. The paper also presents the experimental results of proposed windowing procedure in the marine radar with such the parameters: signal is linear FM (Chirp); frequency deviation DF is 9.375MHz; the pulse width T is 3.2μs taps number in the matched filter is 800 taps; sampling frequency 253.125*106 MHz. It has been realized the reducing of side-lobes levels in real time permitting better resolution of the small targets.

  4. Image processing for hazard recognition in on-board weather radar

    NASA Technical Reports Server (NTRS)

    Kelly, Wallace E. (Inventor); Rand, Timothy W. (Inventor); Uckun, Serdar (Inventor); Ruokangas, Corinne C. (Inventor)

    2003-01-01

    A method of providing weather radar images to a user includes obtaining radar image data corresponding to a weather radar image to be displayed. The radar image data is image processed to identify a feature of the weather radar image which is potentially indicative of a hazardous weather condition. The weather radar image is displayed to the user along with a notification of the existence of the feature which is potentially indicative of the hazardous weather condition. Notification can take the form of textual information regarding the feature, including feature type and proximity information. Notification can also take the form of visually highlighting the feature, for example by forming a visual border around the feature. Other forms of notification can also be used.

  5. Holographic Radar Imaging Privacy Techniques Utilizing Dual-Frequency Implementation

    SciTech Connect

    McMakin, Douglas L.; Hall, Thomas E.; Sheen, David M.

    2008-04-18

    Over the last 15 years, the Pacific Northwest National Laboratory has performed significant research and development activities to enhance the state of the art of holographic radar imaging systems to be used at security checkpoints for screening people for concealed threats hidden under their garments. These enhancement activities included improvements to privacy techniques to remove human features and providing automatic detection of body-worn concealed threats. The enhanced privacy and detection methods used both physical and software imaging techniques. The physical imaging techniques included polarization-diversity illumination and reception, dual-frequency implementation, and high-frequency imaging at 60 GHz. Software imaging techniques to enhance the privacy of the person under surveillance included extracting concealed threat artifacts from the imagery to automatically detect the threat. This paper will focus on physical privacy techniques using dual-frequency implementation.

  6. Apodized RFI filtering of synthetic aperture radar images

    SciTech Connect

    Doerry, Armin Walter

    2014-02-01

    Fine resolution Synthetic Aperture Radar (SAR) systems necessarily require wide bandwidths that often overlap spectrum utilized by other wireless services. These other emitters pose a source of Radio Frequency Interference (RFI) to the SAR echo signals that degrades SAR image quality. Filtering, or excising, the offending spectral contaminants will mitigate the interference, but at a cost of often degrading the SAR image in other ways, notably by raising offensive sidelobe levels. This report proposes borrowing an idea from nonlinear sidelobe apodization techniques to suppress interference without the attendant increase in sidelobe levels. The simple post-processing technique is termed Apodized RFI Filtering (ARF).

  7. Synthetic aperture radar images with composite azimuth resolution

    DOEpatents

    Bielek, Timothy P; Bickel, Douglas L

    2015-03-31

    A synthetic aperture radar (SAR) image is produced by using all phase histories of a set of phase histories to produce a first pixel array having a first azimuth resolution, and using less than all phase histories of the set to produce a second pixel array having a second azimuth resolution that is coarser than the first azimuth resolution. The first and second pixel arrays are combined to produce a third pixel array defining a desired SAR image that shows distinct shadows of moving objects while preserving detail in stationary background clutter.

  8. A prototype of radar-drone system for measuring the surface flow velocity at river sites and discharge estimation

    NASA Astrophysics Data System (ADS)

    Moramarco, Tommaso; Alimenti, Federico; Zucco, Graziano; Barbetta, Silvia; Tarpanelli, Angelica; Brocca, Luca; Mezzanotte, Paolo; Rosselli, Luca; Orecchini, Giulia; Virili, Marco; Valigi, Paolo; Ciarfuglia, Thomas; Pagnottelli, Stefano

    2015-04-01

    Discharge estimation at a river site depends on local hydraulic conditions identified by recording water levels. In fact, stage monitoring is straightforward and relatively inexpensive compared with the cost necessary to carry out flow velocity measurements which are, however, limited to low flows and constrained by the accessibility of the site. In this context the mean flow velocity is hard to estimate for high flow, affecting de-facto the reliability of discharge assessment for extreme events. On the other hand, the surface flow velocity can be easily monitored by using radar sensors allowing to achieve a good estimate of discharge by exploiting the entropy theory applied to rivers hydraulic (Chiu,1987). Recently, a growing interest towards the use of Unmanned Aerial Vehicle (UVA), henceforth drone, for topographic applications is observed and considering their capability drones may be of a considerable interest for the hydrological monitoring and in particular for streamflow measurements. With this aim, for the first time, a miniaturized Doppler radar sensor, operating at 24 GHz, will be mounted on a drone to measure the surface flow velocity in rivers. The sensor is constituted by a single-board circuit (i.e. is a fully planar circuits - no waveguides) with the antenna on one side and the front-end electronic on the other side (Alimenti et al., 2007). The antenna has a half-power beam width of less than 10 degrees in the elevation plane and a gain of 13 dBi. The radar is equipped with a monolithic oscillator and transmits a power of about 4 mW at 24 GHz. The sensor is mounted with an inclination of 45 degrees with respect to the drone flying plane and such an angle is considered in recovering the surface speed of the water. The drone is a quadricopter that has more than 30 min, flying time before recharging the battery. Furthermore its flying plan can be scheduled with a suitable software and is executed thanks to the on-board sensors (GPS, accelerometers

  9. Optimum frequency for subsurface-imaging synthetic-aperture radar

    SciTech Connect

    Brock, B.C.; Patitz, W.E.

    1993-05-01

    A subsurface-imaging synthetic-aperture radar (SISAR) has potential for application in areas as diverse as non-proliferation programs for nuclear weapons to environmental monitoring. However, most conventional synthetic-aperture radars operate at higher microwave frequencies which do not significantly penetrate below the soil surface. This study attempts to provide a basis for determining optimum frequencies and frequency ranges which will allow synthetic-aperture imaging of buried targets. Since the radar return from a buried object must compete with the return from surface clutter, the signal-to-clutter ratio is an appropriate measure of performance for a SISAR. A parameter-based modeling approach is used to model the complex dielectric constant of the soil from measured data obtained from the literature. Theoretical random-surface scattering models, based on statistical solutions to Maxwell's equations, are used to model the clutter. These models are combined to estimate the signal-to-clutter ratio for canonical targets buried in several soil configurations. Initial results indicate that the HF spectrum (3--30 MHz), although it could be used to detect certain targets under some conditions, has limited practical value for use with SISAR, while the upper vhf through uhf spectrum ([approximately]100 MHz--1 GHz) shows the most promise for a general purpose SISAR system. Recommendations are included for additional research.

  10. Compact 625-channel scannerless imaging laser radar receiver

    NASA Astrophysics Data System (ADS)

    Burns, Hoyt N.; Steiner, Todd D.; Hayden, David R.

    1996-06-01

    In 1995, under a USAF SBIR Phase I program, Burns Engineering Corporation investigated the application of new integrated photonics technologies and hybrid manufacturing processes to the miniaturization of an imaging laser radar receiver which has complete receiving and range counting circuitry for each pixel in a 25-by-25 element avalanche photodiode array. The `parallel multichannel' receiver (PMR) is a compact, robust, and modular laser radar subsystem which can produce high resolution 3D range imagery at 1 kHz frame rates without the use of a scanner. The modular PMR is attractive as a common module solution for a wide variety of high performance, low cost, autonomous laser-guided seeker applications. The system described illustrates one approach to integrating and packaging high-density photonic arrays and associated signal processing electronics to yield a high-performance imaging laser radar receiver using existing technology. Burns Engineering has been selected by the USAF to build a benchtop prototype, proof-of-concept demonstrator in a follow-on, SBIR Phase II program.

  11. Logarithmic Laplacian Prior Based Bayesian Inverse Synthetic Aperture Radar Imaging

    PubMed Central

    Zhang, Shuanghui; Liu, Yongxiang; Li, Xiang; Bi, Guoan

    2016-01-01

    This paper presents a novel Inverse Synthetic Aperture Radar Imaging (ISAR) algorithm based on a new sparse prior, known as the logarithmic Laplacian prior. The newly proposed logarithmic Laplacian prior has a narrower main lobe with higher tail values than the Laplacian prior, which helps to achieve performance improvement on sparse representation. The logarithmic Laplacian prior is used for ISAR imaging within the Bayesian framework to achieve better focused radar image. In the proposed method of ISAR imaging, the phase errors are jointly estimated based on the minimum entropy criterion to accomplish autofocusing. The maximum a posterior (MAP) estimation and the maximum likelihood estimation (MLE) are utilized to estimate the model parameters to avoid manually tuning process. Additionally, the fast Fourier Transform (FFT) and Hadamard product are used to minimize the required computational efficiency. Experimental results based on both simulated and measured data validate that the proposed algorithm outperforms the traditional sparse ISAR imaging algorithms in terms of resolution improvement and noise suppression. PMID:27136551

  12. Mapping of glacial landforms from Seasat radar images

    NASA Technical Reports Server (NTRS)

    Ford, J. P.

    1984-01-01

    Glacial landforms in the drumlin drift belt of Ireland and the Alaska Range can be identified and mapped from Seasat synthetic-aperture radar (SAR) images. Drumlins cover 60 percent of the Ireland scene. The width/length ratio of individual drumlins can be measured on the SAR images, allowing regional differences in drumlin shape to be mapped. This cannot be done with corresponding Landsat multispectral scanner (MSS) images because of lower spatial resolution and because of shadowing effects that vary seasonally. The Alaska scene shows the extent and nature of morphological features such as medial and lateral moraines, stagnant ice, and fluted ground moraine in glaciated valleys. Perception of these features on corresponding Landsat MSS images is limited by seasonal diffrences in solar illumination. Because SAR is not affected by such differences or by cloud cover, it is particularly well suited for monitoring glacial movement. The disadvantage of distorted high-relief features on Seasat SAR images can be reduced in future SAR systems by modifying the radar illumination geometry.

  13. Clutter discrimination algorithm simulation in pulse laser radar imaging

    NASA Astrophysics Data System (ADS)

    Zhang, Yan-mei; Li, Huan; Guo, Hai-chao; Su, Xuan; Zhu, Fule

    2015-10-01

    Pulse laser radar imaging performance is greatly influenced by different kinds of clutter. Various algorithms are developed to mitigate clutter. However, estimating performance of a new algorithm is difficult. Here, a simulation model for estimating clutter discrimination algorithms is presented. This model consists of laser pulse emission, clutter jamming, laser pulse reception and target image producing. Additionally, a hardware platform is set up gathering clutter data reflected by ground and trees. The data logging is as clutter jamming input in the simulation model. The hardware platform includes a laser diode, a laser detector and a high sample rate data logging circuit. The laser diode transmits short laser pulses (40ns FWHM) at 12.5 kilohertz pulse rate and at 905nm wavelength. An analog-to-digital converter chip integrated in the sample circuit works at 250 mega samples per second. The simulation model and the hardware platform contribute to a clutter discrimination algorithm simulation system. Using this system, after analyzing clutter data logging, a new compound pulse detection algorithm is developed. This new algorithm combines matched filter algorithm and constant fraction discrimination (CFD) algorithm. Firstly, laser echo pulse signal is processed by matched filter algorithm. After the first step, CFD algorithm comes next. Finally, clutter jamming from ground and trees is discriminated and target image is produced. Laser radar images are simulated using CFD algorithm, matched filter algorithm and the new algorithm respectively. Simulation result demonstrates that the new algorithm achieves the best target imaging effect of mitigating clutter reflected by ground and trees.

  14. Improved Speed and Functionality of a 580-GHz Imaging Radar

    NASA Technical Reports Server (NTRS)

    Dengler, Robert; Cooper, Ken; Chattopadhyay, Goutam; Siegel, Peter; Schlecht, Erich; Mehdi, Imran; Skalare, Anders; Gill, John

    2010-01-01

    With this high-resolution imaging radar system, coherent illumination in the 576-to-589-GHz range and phase-sensitive detection are implemented in an all-solid-state design based on Schottky diode sensors and sources. By employing the frequency-modulated, continuous-wave (FMCW) radar technique, centimeter-scale range resolution has been achieved while using fractional bandwidths of less than 3 percent. The high operating frequencies also permit centimeter-scale cross-range resolution at several-meter standoff distances without large apertures. Scanning of a single-pixel transceiver enables targets to be rapidly mapped in three dimensions, so that the technology can be applied to the detection of concealed objects on persons.

  15. SNR and Contrast Enhancement Techniques for the Photoacoustic Radar Imaging

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Mandelis, Andreas

    2016-07-01

    This paper presents two methods for photoacoustic signal enhancement in biological tissues. One such method is based on the fact that temperature can affect the signals of the photoacoustic radar. Therefore, thermally assisted methods have been used for photoacoustic imaging contrast improvement. Another method is based on harmonic wavelength modulation which results in a differential PA radar signal to strengthen early cancer detection. Two chirped waveforms modulated out-of-phase between 680 nm and 800 nm can effectively suppress the background noise, greatly enhance the SNR and detect small variations in hemoglobin oxygenation levels, thereby distinguishing pre-malignant tumors. Experimental results demonstrate the accuracy of the frequency-modulated differential measurement with sheep blood at different hemoglobin oxygenation (S_tO2) levels.

  16. Shuttle imaging radar A analysis of land use in Amazonia

    NASA Technical Reports Server (NTRS)

    Stone, Thomas A.; Woodwell, George M.

    1988-01-01

    Over large areas in the tropics, satellite imagery is the principal source of data on the area, current stature, and extent of disturbance of the forests. The information from imagery that covers large areas at low resolution is greatly enhanced when different types of imagery can be compared. The paper presents a comparison of data from Landsat MSS and from the Shuttle Imaging Radar (SIR-A) L band HH polarization data for sites in the Amazon Basin. Results indicate that SIR-A backscatter from the undisturbed forest was lower than that from some disturbed areas and from flooded forests and that SIR-A brightness, increases nonlinearly with the Landsat normalized difference vegetation index. It is hypothesized that the brightest radar returns in southern Amazonia are from newly cleared forests that are littered with standing and fallen tree boles that function as corner reflectors; and that backscatter will diminish from disturbed areas over time as fields are burned repeatedly.

  17. Radar Image with Color as Height, Lovea, Cambodia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of Lovea, Cambodia, was acquired by NASA's Airborne Synthetic Aperture Radar (AIRSAR). Lovea, the roughly circular feature in the middle-right of the image, rises some 5 meters (16.4 feet) above the surrounding terrain. Lovea is larger than many of the other mound sites with a diameter of greater than 300 meters (984.3 feet). However, it is one of a number highlighted by the radar imagery. The present-day village of Lovea does not occupy all of the elevated area. However, at the center of the mound is an ancient spirit post honoring the legendary founder of the village. The mound is surrounded by earthworks and has vestiges of additional curvilinear features. Today, as in the past, these harnessed water during the rainy season, and conserved it during the long dry months of the year.

    The village of Lovea located on the mound was established in pre-Khmer times, probably before 500 A.D. In the lower left portion of the image is a large trapeng and square moat. These are good examples of construction during the historical 9th to 14th Century A.D. Khmer period; construction that honored and protected earlier circular villages. This suggests a cultural and technical continuity between prehistoric circular villages and the immense urban site of Angkor. This connection is one of the significant finds generated by NASA's radar imaging of Angkor. It shows that the city of Angkor was a particularly Khmer construction. The temple forms and water management structures of Angkor were the result of pre-existing Khmer beliefs and methods of water management.

    Image dimensions are approximately 6.3 by 4.7 kilometers (3.9 by 2.9 miles). North is at top. Image brightness is from the C-band (5.6 centimeters, or 2.2 inches wavelength) radar backscatter, which is a measure of how much energy the surface reflects back toward the radar. Color is used to represent elevation contours. One cycle of color represents 20 meters (65.6 feet) of elevation change; that is, going

  18. SAR image registration in absolute coordinates using GPS carrier phase position and velocity information

    SciTech Connect

    Burgett, S.; Meindl, M.

    1994-09-01

    It is useful in a variety of military and commercial application to accurately register the position of synthetic aperture radar (SAR) imagery in absolute coordinates. The two basic SAR measurements, range and doppler, can be used to solve for the position of the SAR image. Imprecise knowledge of the SAR collection platform`s position and velocity vectors introduce errors in the range and doppler measurements and can cause the apparent location of the SAR image on the ground to be in error by tens of meters. Recent advances in carrier phase GPS techniques can provide an accurate description of the collection vehicle`s trajectory during the image formation process. In this paper, highly accurate carrier phase GPS trajectory information is used in conjunction with SAR imagery to demonstrate a technique for accurate registration of SAR images in WGS-84 coordinates. Flight test data will be presented that demonstrates SAR image registration errors of less than 4 meters.

  19. Iterative Self-Dual Reconstruction on Radar Image Recovery

    SciTech Connect

    Martins, Charles; Medeiros, Fatima; Ushizima, Daniela; Bezerra, Francisco; Marques, Regis; Mascarenhas, Nelson

    2010-05-21

    Imaging systems as ultrasound, sonar, laser and synthetic aperture radar (SAR) are subjected to speckle noise during image acquisition. Before analyzing these images, it is often necessary to remove the speckle noise using filters. We combine properties of two mathematical morphology filters with speckle statistics to propose a signal-dependent noise filter to multiplicative noise. We describe a multiscale scheme that preserves sharp edges while it smooths homogeneous areas, by combining local statistics with two mathematical morphology filters: the alternating sequential and the self-dual reconstruction algorithms. The experimental results show that the proposed approach is less sensitive to varying window sizes when applied to simulated and real SAR images in comparison with standard filters.

  20. Radar cross-section estimation of SAR images

    NASA Astrophysics Data System (ADS)

    McConnell, Ian; White, Richard G.; Oliver, Christopher J.; Cook, Rod

    1995-11-01

    We present an algorithm that is able to smooth out the speckle from many SAR images and which does not suffer from the drawbacks of multilooking. The algorithm is able to preserve the detail and resolution of the original image while producing a smooth, real-valued output. In many cases the quality of the smoothed image is sufficiently high that it may be used with standard optical post-processing algorithms. We use a global optimization method (simulated annealing) and single point gamma statistics to find the MAP solution for the radar cross- section. However, this method may also be regarded as an ideal adaptive filter that is both computationally efficient and highly parallelizable. Results are presented for airborne, ERS-1 and multi-temporal SAR images.

  1. Mapping of forested wetland: use of Seasat radar images to complement conventional sources ( USA).

    USGS Publications Warehouse

    Place, J.L.

    1985-01-01

    Distinguishing forested wetland from dry forest using aerial photographs is handicapped because photographs often do not reveal the presence of water below tree canopies. Radar images obtained by the Seasat satellite reveal forested wetland as highly reflective patterns on the coastal plain between Maryland and Florida. Seasat radar images may complement aerial photographs for compiling maps of wetland. A test with experienced photointerpreters revealed that interpretation accuracy was significantly higher when using Seasat radar images than when using only conventional sources.-Author

  2. Ultra wide band radar holographic imaging of subsurface targets

    SciTech Connect

    Collins, H.D.; Gribble, R.P.

    1993-08-01

    This report discusses ultra wide band (i.e., 60 ps impulse) radar holography which is a unique technique for imaging subsurface targets with extremely high lateral and depth resolution. The large frequency bandwidth, typically 100%, provides excellent depth resolution and the synthetic aperture optimum lateral resolution of one-half wavelength at the center pulse frequency. Radar impulse holography can simply be described as a multi-frequency detection and imaging technique where the target`s broadband time waveform signals are recorded over a defined aperture; decomposed into their discrete frequency components as single frequency holograms, and reconstructed into a composite image. Computer generated holograms are constructed for each frequency component in the 3-dB pulse bandwidth and plane wave angular spectrums computed to provide unique detection analysis with respect to target identification, etc. The hologram at each frequency component in the pulse can be thought of as a diffraction lens for each reflecting point on the target. A complex target consists, of a multitude of points, and the recorded hologram becomes the superposition of these individual diffraction lens. It is a unique diffraction pattern capable of defining the target`s image and scattering characteristics in the near- and far-field.

  3. Special Issue on Results from Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (Sir-C/X-SAR): Foreword

    NASA Technical Reports Server (NTRS)

    Plaut, Jefferey J.

    1996-01-01

    The two flights of the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the Space Shuttle Endeavour represent a major advance in remote sensing technology for studies of planetary surfaces.

  4. Space Radar Image of Raco, Michigan, ecological test site

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an X-band image of seasonal changes at the ecological test site of Raco, Michigan, located south of Whitefish Bay on Lake Superior. The image is centered at about 46 degrees north latitude and 85 degrees west longitude. This image was acquired by the X-band Synthetic Aperture Radar onboard the space shuttle Endeavour on April 10th, 1994, and on October 1, 1994. The areas shown in red correspond to the April 10th data; the areas in blue correspond to data acquired on October 1, 1994; green indicates the ratio of data acquired on April 10 and October 1, 1994. The area shown is 22.7 kilometers by 53 kilometers (14 miles by 33 miles). Lake Superior in the upper right was frozen in April and had small waves (ripples) on its surface in October. The land area contains mostly forests and, to a lesser extent, agricultural regions. In April the area was covered in wet snow. By October, there agricultural areas were covered with grass. Vegetation and soils were moist due to rainfalls three days before the data was acquired on October 1, 1994. The bright light green/yellow tones in the lower half of the image show the stronger reflections of the snow-covered agricultural fields. The pinkish color corresponds to the coniferous and deciduous forests. The green area represents red pines. These trees are smaller than the surrounding forest cover and allow more radar penetration. The area is green because the radar is sensing the surface, which undergoes great change from snow to grass and fern undergrowth between April and October. The bright green triangle in the upper half of the image is an old airstrip, while the modern airport can be seen on the bottom right side of the image. The Raco site is an important location for monitoring seasonal changes and future global change because it is situated at the ecological transition zone between the boreal forests and the northern temperate forests. This transitional zone is expected to be ecologically sensitive to anticipated

  5. Radar Image with Color as Height, Hariharalaya, Cambodia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Hariharalaya, the ancient 9th Century A.D. capitol of the Khmer in Cambodia, is shown in the upper center portion of this NASA Airborne Synthetic Aperture Radar (AIRSAR) image. The image was acquired during the 1996 PACRIM mission with AIRSAR operating in the TOPSAR mode. At the center of the image is the terraced sandstone temple mountain of the King Indravarman, the Bakong. The smaller enclosed rectangular feature just to the north is Preah Ko. Further to the south are more rectangular features, temples and water reservoirs attributed to other kings in the earlier part of the 9th Century A.D. and maybe even earlier. Just visible at the top on the image is a long linear feature that forms the southern border of the immense water reservoir, at the center of which is the Lolei temple. The city was the first capitol of the Khmer after the 802 A.D. ceremony consecrating the king as 'Devaraja'. This usually translated as 'god who was king' or 'king who was god'. In the next century, the center of power shifted to the northwest, to the area known today as Angkor.

    Thus this early capital is unique both in being the first after the historical 'founding' of the Khmer Empire, and for being inhabited for a relatively short time. Although kings returned from Angkor in the 11th and 12th Centuries A.D. to build the temple known as the Lolei and to construct the tower in the center of Bakong, the city of Hariharalaya remained on the perimeter of royal power. It was revered, however, as part of a longstanding and important custom of ancestral veneration. This manifested itself in a complex set of rituals honoring one's forebears--also ensuring legitimacy for one's claim to the throne. So behind this seemingly simple patterning of rectangles on the radar image lies many layers of history, ritual and meaning for the Khmer people, past and present.

    Image dimensions are approximately 6 by 4.8 kilometers (3.7 by 3 miles) with a pixel spacing of 5 meters (16.4 feet). North is at

  6. Earth resources shuttle imaging radar. [systems analysis and design analysis of pulse radar for earth resources information system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A report is presented on a preliminary design of a Synthetic Array Radar (SAR) intended for experimental use with the space shuttle program. The radar is called Earth Resources Shuttle Imaging Radar (ERSIR). Its primary purpose is to determine the usefulness of SAR in monitoring and managing earth resources. The design of the ERSIR, along with tradeoffs made during its evolution is discussed. The ERSIR consists of a flight sensor for collecting the raw radar data and a ground sensor used both for reducing these radar data to images and for extracting earth resources information from the data. The flight sensor consists of two high powered coherent, pulse radars, one that operates at L and the other at X-band. Radar data, recorded on tape can be either transmitted via a digital data link to a ground terminal or the tape can be delivered to the ground station after the shuttle lands. A description of data processing equipment and display devices is given.

  7. 47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Technical requirements for ground penetrating radars and wall imaging systems. 15.509 Section 15.509 Telecommunication FEDERAL COMMUNICATIONS... ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of an imaging system...

  8. 47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Technical requirements for ground penetrating radars and wall imaging systems. 15.509 Section 15.509 Telecommunication FEDERAL COMMUNICATIONS... ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of an imaging system...

  9. 47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Technical requirements for ground penetrating radars and wall imaging systems. 15.509 Section 15.509 Telecommunication FEDERAL COMMUNICATIONS... ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of an imaging system...

  10. 47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Technical requirements for ground penetrating radars and wall imaging systems. 15.509 Section 15.509 Telecommunication FEDERAL COMMUNICATIONS... ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of an imaging system...

  11. A VLSI Processor Design of Real-Time Data Compression for High-Resolution Imaging Radar

    NASA Technical Reports Server (NTRS)

    Fang, W.

    1994-01-01

    For the high-resolution imaging radar systems, real-time data compression of raw imaging data is required to accomplish the science requirements and satisfy the given communication and storage constraints. The Block Adaptive Quantizer (BAQ) algorithm and its associated VLSI processor design have been developed to provide a real-time data compressor for high-resolution imaging radar systems.

  12. Near-Field Three-Dimensional Radar Imaging Techniques and Applications

    SciTech Connect

    Sheen, David M.; McMakin, Douglas L.; Hall, Thomas E.

    2010-07-01

    Three dimensional radio frequency imaging techniques have been developed for a variety of near field applications including radar cross-section imaging, concealed weapon detection, ground penetrating radar imaging, through-barrier imaging, and non-destructive evaluation. These methods employ active radar transceivers that operate at various frequency ranges covering a wide range from less than 100 MHz to in excess of 350 GHz with the frequency range customized for each application. Computational wavefront reconstruction imaging techniques have been developed that optimize the resolution and illumination quality of the images. In this paper, rectilinear and cylindrical three-dimensional imaging techniques are described along with several application results.

  13. Size estimate of (99942) Apophis based on radar imaging

    NASA Astrophysics Data System (ADS)

    Brozovic, Marina; Benner, Lance; McMichael, Joseph; Pravec, Petr; Scheirich, Petr; Giorgini, Jon; Magri, Chris; Busch, Michael; Jao, Joseph; Lee, Clement; Nolan, Michael; Taylor, Patrick; Howell, Ellen; Slade, Martin

    2015-11-01

    (99942) Apophis is one of the most important near-Earth asteroids ever discovered. It will make a very close Earth approach on Friday, April 13, 2029 when it will pass within only a few Earth radii above Earth's surface. This will be the closest approach by something this large currently known. Apophis approached within 0.1 au in January of 2013, and we organized an extensive radar campaign at Goldstone and Arecibo between December 2012 and March 2013. Our primary objective was to obtain ranging measurements to improve the orbit, characterize its physical properties, and facilitate detection of the Yarkovsky effect leading to estimation of the mass and bulk density. We obtained frequency-only data, and 150 m and 75 m ranging data. The signal-to-noise ratios (SNRs) were strong enough so that coarsely resolved delay-Doppler images revealed aspects of Apophis’ shape. The visible extents varied from ~0.2 km to ~0.4 km and the bandwidths varied from 0.9 Hz to1.4 Hz. The object is clearly elongated, which is consistent with the large lightcurve amplitude of ~0.9 mag reported by Behrend et al. ( http://obswww.unige.ch/~behrend/r099942a.png) and Pravec et al. (Icarus 233, 48-60, 2014). The radar images suggest that Apophis could be a contact binary.Pravec et al. have estimated the shape and spin of Apophis from lightcurves that were collected at similar times as our radar data. The radar data were not strong enough for 3D shape modeling, but we used the Shape software (Hudson, Remote Sens. Rev. 8, 195-203, 1993 and Magri et al., Icarus 186, 152-177, 2007) to scale the convex lightcurve-derived shape model to fit the radar data. We find that the best χ2 value corresponds to the model that has 0.43×0.30×0.26 (±0.04, ±0.03, ±0.03) km for long, intermediate, and short axis, and a dynamically equivalent, equal volume ellipsoid of 0.31±0.03 km.

  14. Focusing of synthetic aperture radar ocean images with long integration times

    NASA Astrophysics Data System (ADS)

    Kasilingam, Dayalan P.; Hayt, David W.; Shemdin, Omar H.

    1991-09-01

    Synthetic aperture radar (SAR) images obtained in the SAR and X Band Ocean Nonlinearities: Chesapeake Light Tower (SAXON:CLT) experiment are processed with long integration times (6 s) and analyzed to study the effects of focusing. Two images with near-azimuth-traveling waves were chosen for the study. The first image consists of relatively short wavelength wind waves traveling in the same general direction as the aircraft. The second image consists of a long Atlantic swell traveling in the opposite direction to the aircraft. At these long integration times the image spectral intensities are found to be sensitive to the focus setting. The spectral intensity at the optimum focus is 400% of that at zero focus for the first image and 167% for the second image. The focusing curves for both images agree well with those predicted by a model developed by several groups and referred to here as the "consensus" model. This model predicts an optimum focus setting that is equal to one half of the effective phase speed of the dominant wave in the azimuth direction. The velocity bunching model underpredicts the optimum focus setting significantly. The study concludes that in long-integration-time SAR processing of surface waves, such as the spotlight mode, the image contrast is sensitively dependent on the focus setting and that the optimum focus setting is given by one half of the effective phase speed of the dominant surface wave.

  15. Louis Essen and the Velocity of Light: From Wartime Radar to Unit of Length

    NASA Astrophysics Data System (ADS)

    Essen, Ray

    2010-03-01

    Louis Essen (1908-1997), working at the National Physical Laboratory in Teddington, England, was the first scientist to realize that the value for the velocity of light used widely during World War II was incorrect. In 1947 he published his first determination of it, which was 16 kilometers per second higher than the accepted value, causing a great deal of controversy in the scientific community. His new value was not accepted for several years, until it was shown that it improved the precision of range-finding by radar. Essen’s result has remained as the internationally accepted value despite a number of attempts to improve on it. I discuss Essen’s work and also examine other optical and nonoptical determinations that were made in the United States, and their limits of accuracy. I also identify the reasons why it took so long for Essen’s new value to be accepted, and how it led to changes in the definition of the units of length and time.

  16. Hybrid lidar radar receiver for underwater imaging applications

    NASA Astrophysics Data System (ADS)

    Seetamraju, Madhavi; Gurjar, Rajan; Squillante, Michael; Derderian, Jeffrey P.

    2009-05-01

    In this work, we present research performed to improve the receiver characteristics for underwater imaging applications using the hybrid lidar-radar detection technique. We report the development of the next-generation coherent heterodyne receiver using modulation of the optical receiver's amplifier gain. Significant advantages in the receiver specifications are achieved using a large-area, high gain, low-noise silicon avalanche photodiode (APD) as the photodetector cum frequency mixer-demodulator. We demonstrate that heterodyne detection by gain modulation of APD can be used to increase the signal-to-noise ratio, detection sensitivity and bandwidth for the hybrid receiver system.

  17. 3-D Imaging of Partly Concealed Targets by Laser Radar

    DTIC Science & Technology

    2005-10-01

    laser in the green wavelength region was used for illumination. 3-D Imaging of Partly Concealed Targets by Laser Radar 11 - 8 RTO-MP-SET-094...acknowledge Marie Carlsson and Ann Charlotte Gustavsson for their assistance in some of the experiments. 7.0 REFERENCES [1] U. Söderman, S. Ahlberg...SPIE Vol. 3707, pp. 432-448, USA, 1999. [14] D. Letalick, H. Larsson, M. Carlsson, and A.-C. Gustavsson , “Laser sensors for urban warfare,” FOI

  18. Radar target imaging by time-domain inverse scattering

    NASA Astrophysics Data System (ADS)

    Morag, M.

    1981-03-01

    This thesis describes the study and development of a workable inverse scattering method for imaging and identification of radar targets. The space-time integral approach is used for iterative target shape reconstruction. Following an overview of transient electromagnetics, the integral equation is applied for thin-wire transient response computation. The analytical time domain integral equation is derived and solved numerically, for general conducting bodies of revolution. Finally the algorithm for an inverse scattering computer solution is derived and tested under simulation of physical environments.

  19. Minimum description length synthetic aperture radar image segmentation.

    PubMed

    Galland, Frédéric; Bertaux, Nicolas; Réfrégier, Philippe

    2003-01-01

    We present a new minimum description length (MDL) approach based on a deformable partition--a polygonal grid--for automatic segmentation of a speckled image composed of several homogeneous regions. The image segmentation thus consists in the estimation of the polygonal grid, or, more precisely, its number of regions, its number of nodes and the location of its nodes. These estimations are performed by minimizing a unique MDL criterion which takes into account the probabilistic properties of speckle fluctuations and a measure of the stochastic complexity of the polygonal grid. This approach then leads to a global MDL criterion without an undetermined parameter since no other regularization term than the stochastic complexity of the polygonal grid is necessary and noise parameters can be estimated with maximum likelihood-like approaches. The performance of this technique is illustrated on synthetic and real synthetic aperture radar images of agricultural regions and the influence of different terms of the model is analyzed.

  20. Focusing simulations of synthetic aperture radar ocean images

    NASA Astrophysics Data System (ADS)

    Hayt, D. W.; Alphers, W.; Brüning, C.; Dewitt, R.; Henyey, F.; Kasilingam, D. P.; Keller, W. C.; Lyzenga, D. R.; Plant, W. J.; Schult, R. L.; Shemdin, O. H.; Wright, J. A.

    1990-09-01

    The SAR ocean images obtained in the Tower Ocean Wave and Radar Dependence Experiment (TOWARD) are carefully analyzed at different focus settings and compared with simulated results based on various theories for imaging surface waves. The agreement between the experimental data and all of the SAR simulations except one is found to be favorable. There is also surprisingly close agreement among the different theoretical models themselves, suggesting a closer fundamental similarity among the contending theories than was previously thought. It is shown that the width of the focusing curve has an inverse dependence on the SAR integration time. For the TOWARD conditions it is found that the image modulation due to azimuth-traveling surface waves is greater than that due to range-traveling waves.

  1. Automatic aircraft landing using interferometric inverse synthetic aperture radar imaging.

    PubMed

    Soumekh, M

    1996-01-01

    This paper presents an interferometric processing of an aircraft's monostatic and bistatic inverse synthetic aperture radar (ISAR) signatures for automatic landing. The aircraft's squint angle in this ISAR imaging problem is near 90 degrees . We show that this extreme squint angle does not pose any problem for the ISAR Fourier-based (wavefront) reconstruction algorithm. In fact, the aircraft can be imaged accurately, and without any erroneous shifts in the cross-range domain, within the imposed theoretical resolution. Moreover, the algorithm is accurate enough such that one can utilize the phase of the ISAR monostatic and bistatic measurements for interferometric processing. The resultant interferometric ISAR image is used to detect undesirable rotations in the aircraft's orientation.

  2. On 3D radar data visualization and merging with camera images

    NASA Astrophysics Data System (ADS)

    Kjellgren, J.

    2008-10-01

    The possibilities to support the interpretation of spatial 3D-radar data visually both with and without camera images are studied. Radar measurements and camera pictures of a person are analyzed. First, the received signal amplitudes distributed in three dimensions, spherical range and two angles, are fed to a selection procedure using amplitude and the scene volume of interest. A number of resolution cells will then form images based on a volume representation depending upon the amplitude and location. Projecting the images of all the cells upon an imaging plane then forms the total image. Different images of a radar data set are performed for different projecting planes. The images were studied to find efficient aspect angles to get the target information of most interest. Rotating the target data around a suitable axis may perform such search. In addition, a visualization method for presenting radar data merged with a camera picture has been developed. An aim in this part of the work has been to keep the high information content of the camera image in the merged image. From the 3D-radar measurements the radar data may be projected upon the imaging plane of a camera with an arbitrary viewing center. This possibility is presented in examples with one camera looking at the target scene from the radar location and another camera looking from an aspect angle differing 45° relative to the aspect angle of the radar.

  3. Contractile analysis with kriging based on MR myocardial velocity imaging.

    PubMed

    Lee, Su-Lin; Huntbatch, Andrew; Yang, Guang-Zhong

    2008-01-01

    Diagnosis and treatment of coronary artery disease requires a full understanding of the intrinsic contractile mechanics of the heart. MR myocardial velocity imaging is a promising technique for revealing intramural cardiac motion but its ability to depict 3D strain tensor distribution is constrained by anisotropic voxel coverage of velocity imaging due to limited imaging slices and the achievable SNR in patient studies. This paper introduces a novel Kriging estimator for simultaneously improving the tracking and dense inter-slice estimation of the myocardial velocity data. A harmonic embedding technique is employed to determine point correspondence between left ventricle models between subjects, allowing for a statistical shape model to be reconstructed. The use of different semivariograms is investigated for optimal deformation reconstruction. Results from in vivo data demonstrate a marked improvement in tracking myocardial deformation, thus enhancing the potential clinical value of MR myocardial velocity imaging.

  4. Ice-flow reorganization in West Antarctica 2.5 kyr ago dated using radar-derived englacial flow velocities

    NASA Astrophysics Data System (ADS)

    Kingslake, Jonathan; Martín, Carlos; Arthern, Robert J.; Corr, Hugh F. J.; King, Edward C.

    2016-09-01

    We date a recent ice-flow reorganization of an ice divide in the Weddell Sea Sector, West Antarctica, using a novel combination of inverse methods and ice-penetrating radars. We invert for two-dimensional ice flow within an ice divide from data collected with a phase-sensitive ice-penetrating radar while accounting for the effect of firn on radar propagation and ice flow. By comparing isochronal layers simulated using radar-derived flow velocities with internal layers observed with an impulse radar, we show that the divide's internal structure is not in a steady state but underwent a disturbance, potentially implying a regional ice-flow reorganization, 2.5 (1.8-2.9) kyr B.P. Our data are consistent with slow ice flow in this location before the reorganization and the ice divide subsequently remaining stationary. These findings increase our knowledge of the glacial history of a region that lacks dated constraints on late-Holocene ice-sheet retreat and provides a key target for models that reconstruct and predict ice-sheet behavior.

  5. Space Radar Image of Prince Albert, Canada, seasonal

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a comparison of images over Prince Albert, produced by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar aboard the space shuttle Endeavour on its 20th orbit on April 10, 1994, and again on orbit 20 of the second flight of Endeavour on October 1, 1994. The area is centered at 53.91 degrees north latitude and 104.69 degrees west longitude and is located 40 kilometers (25 miles) north and 30 kilometers (18.5 miles) east of the town of Prince Albert in the Saskatchewan province of Canada. The image covers the area east of Candle Lake, between the gravel highway of 120 and west of highway 106. The area imaged is near the southern limit of the boreal forest. The boreal forest of North America is a continuous vegetation belt at high latitudes stretching across the continent from the Atlantic shoreline of central Labrador and then westward across Canada to the interior mountains and central coastal plains of Alaska. The forest is also part of a larger northern hemisphere circumpolar boreal forest belt. Coniferous trees dominate the entire forest but deciduous trees are also present. During the month of April, the forest experiences seasonal changes from a frozen condition to a thawed condition. The trees are completely frozen over the winter season and the forest floor is covered by snow. As the average temperature rises in the spring, the trees are thawed and the snow melts. This transition has an impact on the rate of moisture evaporation and release of carbon dioxide into the atmosphere. In late September and early October, the boreal forest experiences a relatively different seasonal change. At this time, the leaves on deciduous trees start changing color and dropping off. The soil and trees are quite often moist due to frequent rainfall and cloud cover. The evaporation of moisture and carbon dioxide into the atmosphere also diminishes at this time. SIR-C/X-SAR is sensitive to the moisture of soil and vegetation and can sense this freeze

  6. Space Radar Image of Prince Albert, Canada, seasonal

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a comparison of images over Prince Albert, produced by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar aboard the space shuttle Endeavour on its 20th orbit on April 10, 1994, and again on orbit 20 of the second flight of Endeavour on October 1, 1994. The area is centered at 53.91 degrees north latitude and 104.69 degrees west longitude and is located 40 kilometers (25 miles) north and 30 kilometers (18.5 miles) east of the town of Prince Albert in the Saskatchewan province of Canada. The image covers the area east of Candle Lake, between the gravel highway of 120 and west of highway 106. The area imaged is near the southern limit of the boreal forest. The boreal forest of North America is a continuous vegetation belt at high latitudes stretching across the continent from the Atlantic shoreline of central Labrador and then westward across Canada to the interior mountains and central coastal plains of Alaska. The forest is also part of a larger northern hemisphere circumpolar boreal forest belt. Coniferous trees dominate the entire forest but deciduous trees are also present. During the month of April, the forest experiences seasonal changes from a frozen condition to a thawed condition. The trees are completely frozen over the winter season and the forest floor is covered by snow. As the average temperature rises in the spring, the trees are thawed and the snow melts. This transition has an impact on the rate of moisture evaporation and release of carbon dioxide into the atmosphere. In late September and early October, the boreal forest experiences a relatively different seasonal change. At this time, the leaves on deciduous trees start changing color and dropping off. The soil and trees are quite often moist due to frequent rainfall and cloud cover. The evaporation of moisture and carbon dioxide into the atmosphere also diminishes at this time. SIR-C/X-SAR is sensitive to the moisture of soil and vegetation and can sense this freeze

  7. Space Radar Image of Jerusalem and the Dead Sea

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This space radar image shows the area surrounding the Dead Sea along the West Bank between Israel and Jordan. This region is of major cultural and historical importance to millions of Muslims, Jews and Christians who consider it the Holy Land. The yellow area at the top of the image is the city of Jericho. A portion of the Dead Sea is shown as the large black area at the top right side of the image. The Jordan River is the white line at the top of the image which flows into the Dead Sea. Jerusalem, which lies in the Judaean Hill Country, is the bright, yellowish area shown along the left center of the image. Just below and to the right of Jerusalem is the town of Bethlehem. The city of Hebron is the white, yellowish area near the bottom of the image. The area around Jerusalem has a history of more than 2,000 years of settlement and scientists are hoping to use these data to unveil more about this region's past. The Jordan River Valley is part of an active fault and rift system that extends from southern Turkey and connects with the east African rift zone. This fault system has produced major earthquakes throughout history and some scientists theorize that an earthquake may have caused the fall of Jericho's walls. The Dead Sea basin is formed by active earthquake faulting and contains the lowest place on the Earth's surface at about 400 meters (1,300 feet) below sea level. It was in caves along the northern shore of the Dead Sea that the Dead Sea Scrolls were found in 1947. The blue and green areas are generally regions of undeveloped hills and the dark green areas are the smooth lowlands of the Jordan River valley. This image is 73 kilometers by 45 kilometers (45 miles by 28 miles) and is centered at 31.7 degrees north latitude, 35.4 degrees east longitude. North is toward the upper left. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and vertically received; green is L-band, horizontally

  8. Subsurface object position and image correction for standoff ground penetrating radar

    NASA Astrophysics Data System (ADS)

    Kane, R. J.

    1994-05-01

    Present applications of standoff (airborne) Ground Penetrating Synthetic Aperture Radar (SAR) allows objects near the surface to be detected but only provides an approximation for the actual location and image. When single media models are employed the lack of correction for the phase velocity and refractive changes at the air/soil interface result in object distortions. Positional errors and image distortions comparable to the size of the object are possible. Correction is possible, if the media properties are known, by modeling the scene as a two-layer medium and accounting for the propagation effects. The propagation parameters for the lower media are estimated in the migration of observable responses for surface and subsurface objects. This approach allows for corrected images to subsurface objects to be produced after data collection. Surface objects will be distorted as a result of this process. The modeling process, simulations, and results with field data will be discussed. An improvement by a factor of two would enable standoff radar to detect objects at depths of one meter or more benefitting Unexploded Ordnance (UXO) and hazardous waste site survey activities.

  9. Passive Multistatic Radar Imaging using an OFDM Based Signal of Opportunity

    DTIC Science & Technology

    2012-03-22

    is still continuing at this time. This current resurgence includes research in the areas of passive bistatic radar (PBR) and bistatic SAR . This... SAR imaging, bistatic /pas- sive radar, OFDM signals, and phase correction techniques explored throughout the research effort are introduced. Chapter...introduction on bistatic radar and the associated geometry differences to the monostatic case. A discussion of SAR imaging and the algorithm of

  10. Onboard Data Processor for Change-Detection Radar Imaging

    NASA Technical Reports Server (NTRS)

    Lou, Yunling; Muellerschoen, Ronald J.; Chien, Steve A.; Saatchi, Sasan S.; Clark, Duane

    2008-01-01

    A computer system denoted a change-detection onboard processor (CDOP) is being developed as a means of processing the digitized output of a synthetic-aperture radar (SAR) apparatus aboard an aircraft or spacecraft to generate images showing changes that have occurred in the terrain below between repeat passes of the aircraft or spacecraft over the terrain. When fully developed, the CDOP is intended to be capable of generating SAR images and/or SAR differential interferograms in nearly real time. The CDOP is expected to be especially useful for understanding some large-scale natural phenomena and/or mitigating natural hazards: For example, it could be used for near-real-time observation of surface changes caused by floods, landslides, forest fires, volcanic eruptions, earthquakes, glaciers, and sea ice movements. It could also be used to observe such longer-term surface changes as those associated with growth of vegetation (relevant to estimation of wildfire fuel loads). The CDOP is, essentially, an interferometric SAR processor designed to operate aboard a radar platform.

  11. Imaging observations of nighttime mid-latitude F-region field-aligned irregularities by an MU radar ultra-multi-channel system

    NASA Astrophysics Data System (ADS)

    Saito, S.; Yamamoto, M.; Hashiguchi, H.

    2008-08-01

    Mid-latitude F-region field-aligned irregularities (FAIs) were studied by using the middle-and-upper atmosphere (MU) radar ultra-multi-channel system with the radar imaging technique. On 12 June 2006, F-region FAI echoes with a period of about one hour were observed intermittently. These echoes were found to be embedded in medium-scale traveling ionospheric disturbances (MSTIDs) observed as variations of total electron content (TEC). The echoes drifting away from (toward) the radar were observed in the depletion (enhancement) phase of the MSTID. The Doppler velocity of the echoes is consistent with the range rates in the the range-time-intensity (RTI) maps. Fine scale structures with a spatial scale of 10 km or less were found by the radar imaging analysis. Those structures with positive Doppler velocities (moving away from the radar) appeared to drift north- (up-) westward, and those with negative Doppler velocities south- (down-) eastward approximately along the wavefronts of the MSTID. FAIs with positive Doppler velocities filling TEC depletion regions were observed.

  12. Calving and velocity variations observed by Terrestrial Radar Interferometry at Jakobshavn Isbræ, Greenland, in 2015

    NASA Astrophysics Data System (ADS)

    Xie, S.; Voytenko, D.; Holland, D.; Dixon, T. H.

    2015-12-01

    We observed the highly dynamic terminus of Jakobshavn Isbræ in Greenland by using a Terrestrial Radar Interferometer (TRI) during a 5 days' period in early June, 2015. Calving and ice surface velocity variations were captured by our continuous measurements with a sampling rate of 90 seconds. Our terrestrial-derived time series show that calving events are characterized by suddenly fluctuations in surface velocities, which is very distinct in the mélange and less distinct on the glacier. Except for the relatively fast and steady motion, the glacier also moves in response to the semidiurnal ocean tides, and the impact of tides decreases rapidly upstream from the terminus.

  13. Spatially variant apodization for squinted synthetic aperture radar images.

    PubMed

    Castillo-Rubio, Carlos F; Llorente-Romano, Sergio; Burgos-García, Mateo

    2007-08-01

    Spatially variant apodization (SVA) is a nonlinear sidelobe reduction technique that improves sidelobe level and preserves resolution at the same time. This method implements a bidimensional finite impulse response filter with adaptive taps depending on image information. Some papers that have been previously published analyze SVA at the Nyquist rate or at higher rates focused on strip synthetic aperture radar (SAR). This paper shows that traditional SVA techniques are useless when the sensor operates with a squint angle. The reasons for this behaviour are analyzed, and a new implementation that largely improves the results is presented. The algorithm is applied to simulated SAR images in order to demonstrate the good quality achieved along with efficient computation.

  14. Advanced ground-penetrating, imaging radar for bridge inspection

    SciTech Connect

    Warhus, J.P.; Mast, J.E.; Johansson, E.M.; Nelson, S.E.; Lee, Hua

    1993-08-01

    Inspecting high-value structures, like bridges and buildings using Ground Penetrating Radar (GPR) is an application of the technology that is growing in importance. In a typical inspection application, inspectors use GPR to locate structural components, like reinforcing bars embedded in concrete, to avoid weakening the structure while collecting core samples for detailed inspection. Advanced GPR, integrated with imaging technologies for use as an NDE tool, can provide the capability to locate and characterize construction flaws and wear- or age-induced damage in these structures without the need for destructive techniques like coring. In the following sections, we discuss an important inspection application, namely, concrete bridge deck inspection. We describe an advanced bridge deck inspection system concept and provide an overview of a program aimed at developing such a system. Examples of modeling, image reconstruction, and experimental results are presented.

  15. Instrument calibration architecture of Radar Imaging Satellite (RISAT-1)

    NASA Astrophysics Data System (ADS)

    Misra, T.; Bhan, R.; Putrevu, D.; Mehrotra, P.; Nandy, P. S.; Shukla, S. D.; Rao, C. V. N.; Dave, D. B.; Desai, N. M.

    2016-05-01

    Radar Imaging Satellite (RISAT-1) payload system is configured to perform self-calibration of transmit and receive paths before and after imaging sessions through a special instrument calibration technique. Instrument calibration architecture of RISAT-1 supported ground verification and validation of payload including active array antenna. During on-ground validation of 126 beams of active array antenna which needed precise calibration of boresight pointing, a unique method called "collimation coefficient error estimation" was utilized. This method of antenna calibration was supported by special hardware and software calibration architecture of RISAT-1. This paper concentrates on RISAT-1 hardware and software architecture which supports in-orbit and on-ground instrument calibration. Efforts are also put here to highlight use of special calibration scheme of RISAT-1 instrument to evaluate system response during ground verification and validation.

  16. Shuttle synthetic aperture radar implementation study, volume 1. [flight instrument and ground data processor system for collecting raw imaged radar data

    NASA Technical Reports Server (NTRS)

    Mehlis, J. G.

    1976-01-01

    Results of an implementation study for a synthetic aperture radar for the space shuttle orbiter are described. The overall effort was directed toward the determination of the feasibility and usefulness of a multifrequency, multipolarization imaging radar for the shuttle orbiter. The radar is intended for earth resource monitoring as well as oceanographic and marine studies.

  17. Adaptive sparse reconstruction with joint parametric estimation for high-speed uniformly moving targets in coincidence imaging radar

    NASA Astrophysics Data System (ADS)

    Zha, Guofeng; Wang, Hongqiang; Yang, Zhaocheng; Cheng, Yongqiang; Qin, Yuliang

    2016-04-01

    As a complementary imaging technology, coincidence imaging radar (CIR) achieves high resolution for stationary or low-speed targets under the assumption of ignoring the influence of the original position mismatching. As to high-speed moving targets moving from the original imaging cell to other imaging cells during imaging, it is inaccurate to reconstruct the target using the previous imaging plane. We focus on the recovery problem for high-speed moving targets in the CIR system based on the intrapulse frequency random modulation signal in a single pulse. The effects induced by the motion on the imaging performance are analyzed. Because the basis matrix in the CIR imaging equation is determined by the unknown velocity parameter of the moving target, both the target images and basis matrix should be estimated jointly. We propose an adaptive joint parametric estimation recovery algorithm based on the Tikhonov regularization method to update the target velocity and basis matrix adaptively and recover the target images synchronously. Finally, the target velocity and target images are obtained in an iterative manner. Simulation results are presented to demonstrate the efficiency of the proposed algorithm.

  18. Imaging of Vector Electric Fields Surrounding Auroral Arcs from Multibeam Incoherent Scatter Radar Measurements.

    NASA Astrophysics Data System (ADS)

    Maksimova, N.; Varney, R. H.; Cosgrove, R. B.; Kaeppler, S. R.; Nicolls, M. J.

    2015-12-01

    Evaluating the ionospheric electric fields and current systems surrounding auroral arcs aids in distinguishing physical mechanisms that drive arc generation and current closure. Auroral forms involve spatial scales that are small in comparison with the magnetosphere-ionosphere-thermosphere (MIT) system, and yet these forms are thought to be closely tied to the overall system response. Spatially resolved measurements of the horizontal ionospheric current can, in principle, be used to determine the field-aligned currents (FAC) that are responsible for energy transfer between the magnetosphere and the ionosphere/thermosphere, leading to heating and upwelling of the neutral gas and acceleration of ion upflows and outflows. Furthermore, the closure of FACs in the ionosphere regulates modes of magnetospheric convection and substorms. An algorithm has been developed to image the local structure in the convection electric field using multibeam incoherent scatter radar (ISR) measurements. Given the inherent difficulty of reconstructing vector quantities from line of sight (LOS) velocity measurements, the algorithm's aim is to select from the solution space for the possible field configurations a unique solution for the electric field distribution by constraining the reconstructed electric field to reproduce the LOS measurements within measurement errors while simultaneously minimizing a measure of the field's curvature and absolute gradient. Using the method of Lagrange multipliers, the algorithm regularizes the underdetermined problem defined by the LOS radar velocity measurements and guarantees a unique solution when the average measurement error is smaller than the average measurement amplitude. The algorithm is tested on a variety of simulated fields in a sensitivity study to determine the extent to which the solution depends on the a priori assumptions and the observation geometry. In addition, a case study of a quiescent auroral arc observed by the Poker Flat

  19. Refocus of constant velocity moving targets in synthetic aperture radar imagery

    SciTech Connect

    Jakowatz, C.V. Jr.; Wahl, D.E.; Eichel, P.H.

    1998-04-01

    The detection and refocus of moving targets in SAR imagery is of interest in a number of applications. In this paper the authors address the problem of refocusing a blurred signature that has by some means been identified as a moving target. They assume that the target vehicle velocity is constant, i.e., the motion is in a straight line with constant speed. The refocus is accomplished by application of a two-dimensional phase function to the phase history data obtained via Fourier transformation of an image chip that contains the blurred moving target data. By considering separately the phase effects of the range and cross-range components of the target velocity vector, they show how the appropriate phase correction term can be derived as a two-parameter function. They then show a procedure for estimating the two parameters, so that the blurred signature can be automatically refocused. The algorithm utilizes optimization of an image domain contrast metric. They present results of refocusing moving targets in real SAR imagery by this method.

  20. Development of a digital receiver for range imaging atmospheric radar

    NASA Astrophysics Data System (ADS)

    Yamamoto, Masayuki K.; Fujita, Toshiyuki; Abdul Aziz, Noor Hafizah Binti; Gan, Tong; Hashiguchi, Hiroyuki; Yu, Tian-You; Yamamoto, Mamoru

    2014-10-01

    In this paper, we describe a new digital receiver developed for a 1.3-GHz range imaging atmospheric radar. The digital receiver comprises a general-purpose software-defined radio receiver referred to as the Universal Software Radio Peripheral 2 (USRP2) and a commercial personal computer (PC). The receiver is designed to collect received signals at an intermediate frequency (IF) of 130 MHz with a sample rate of 10 MS s-1. The USRP2 digitizes IF received signals, produces IQ time series, and then transfers the IQ time series to the PC through Gigabit Ethernet. The PC receives the IQ time series, performs range sampling, carries out filtering in the range direction, decodes the phase-modulated received signals, integrates the received signals in time, and finally saves the processed data to the hard disk drive (HDD). Because only sequential data transfer from the USRP2 to the PC is available, the range sampling is triggered by transmitted pulses leaked to the receiver. For range imaging, the digital receiver performs real-time signal processing for each of the time series collected at different frequencies. Further, the receiver is able to decode phase-modulated oversampled signals. Because the program code for real-time signal processing is written in a popular programming language (C++) and widely used libraries, the signal processing is easy to implement, reconfigure, and reuse. From radar experiments using a 1 -μs subpulse width and 1-MHz frequency span (i.e., 2-MHz frequency bandwidth), we demonstrate that range imaging in combination with oversampling, which was implemented for the first time by the digital receiver, is able to resolve the fine-scale structure of turbulence with a vertical scale as small as 100 m or finer.

  1. Radar imaging and physical characterization of near-Earth Asteroid (162421) 2000 ET70

    NASA Astrophysics Data System (ADS)

    Naidu, Shantanu P.; Margot, Jean-Luc; Busch, Michael W.; Taylor, Patrick A.; Nolan, Michael C.; Brozovic, Marina; Benner, Lance A. M.; Giorgini, Jon D.; Magri, Christopher

    2013-09-01

    We observed near-Earth Asteroid (162421) 2000 ET70 using the Arecibo and Goldstone radar systems over a period of 12 days during its close approach to the Earth in February 2012. We obtained continuous wave spectra and range-Doppler images with range resolutions as fine as 15 m. Inversion of the radar images yields a detailed shape model with an effective spatial resolution of 100 m. The asteroid has overall dimensions of 2.6 km × 2.2 km × 2.1 km (5% uncertainties) and a surface rich with kilometer-scale ridges and concavities. This size, combined with absolute magnitude measurements, implies an extremely low albedo (∼2%). It is a principal axis rotator and spins in a retrograde manner with a sidereal spin period of 8.96 ± 0.01 h. In terms of gravitational slopes evaluated at scales of 100 m, the surface seems mostly relaxed with over 99% of the surface having slopes less than 30°, but there are some outcrops at the north pole that may have steeper slopes. Our precise measurements of the range and velocity of the asteroid, combined with optical astrometry, enables reliable trajectory predictions for this potentially hazardous asteroid in the interval 460-2813.

  2. Imaging the subsurface stratigraphy in the Ubehebe hydrovolcanic field (Death Valley, California) using ground penetrating radar

    NASA Astrophysics Data System (ADS)

    Cagnoli, B.; Russell, J. K.

    2000-02-01

    Ground penetrating radar (GPR) surveys were carried out to collect subsurface images of the basaltic base surge deposits in the Ubehebe hydrovolcanic field, Death Valley National Park, California. Antennae with frequencies of 50, 100 and 200 MHz were used. This technique allowed the collection of useful geologic data, for example, the lower stratigraphic boundary of the pyroclastic deposits can be imaged and their thickness can be estimated. Different radar responses were also obtained from base surge deposits and underlying sedimentary rocks, which enable their recognition where no outcrops are available. Furthermore, GPR data confirmed the presence of small, eroded craters, which are partially filled by alluvium. In this case, an unconformity between the overlying, horizontally bedded alluvium and the underlying bowl-shaped base surge deposits can be recognized within the crater and the thickness of the alluvium estimated. Common mid-point (CMP) surveys suggested subsurface velocities of the electromagnetic waves in the upper part of these deposits between 0.095-0.1 m/ns.

  3. Three-dimensional subsurface imaging synthetic aperture radar

    SciTech Connect

    Moussally, G.J.

    1995-03-01

    The objective of this applied research and development project is to develop a system known as `3-D SISAR`. This system consists of a ground penetrating radar with software algorithms designed for the detection, location, and identification of buried objects in the underground hazardous waste environments found at DOE storage sites. Three-dimensional maps of the object locations will be produced which can assist the development of remediation strategies and the characterization of the digface during remediation operations. It is expected that the 3-D SISAR will also prove useful for monitoring hydrocarbon based contaminant migration after remediation. The underground imaging technique being developed under this contract utilizes a spotlight mode Synthetic Aperture Radar (SAR) approach which, due to its inherent stand-off capability, will permit the rapid survey of a site and achieve a high degree of productivity over large areas. When deployed from an airborne platform, the stand-off techniques is also seen as a way to overcome practical survey limitations encountered at vegetated sites.

  4. Determining titan's spin state from cassini radar images

    USGS Publications Warehouse

    Stiles, B.W.; Kirk, R.L.; Lorenz, R.D.; Hensley, S.; Lee, E.; Ostro, S.J.; Allison, M.D.; Callahan, P.S.; Gim, Y.; Iess, L.; Del Marmo, P.P.; Hamilton, G.; Johnson, W.T.K.; West, R.D.

    2008-01-01

    For some 19 areas of Titan's surface, the Cassini RADAR instrument has obtained synthetic aperture radar (SAR) images during two different flybys. The time interval between flybys varies from several weeks to two years. We have used the apparent misregistration (by 10-30 km) of features between separate flybys to construct a refined model of Titan's spin state, estimating six parameters: north pole right ascension and declination, spin rate, and these quantities' first time derivatives We determine a pole location with right ascension of 39.48 degrees and declination of 83.43 degrees corresponding to a 0.3 degree obliquity. We determine the spin rate to be 22.5781 deg day -1 or 0.001 deg day-1 faster than the synchronous spin rate. Our estimated corrections to the pole and spin rate exceed their corresponding standard errors by factors of 80 and 8, respectively. We also found that the rate of change in the pole right ascension is -30 deg century-1, ten times faster than right ascension rate of change for the orbit normal. The spin rate is increasing at a rate of 0.05 deg day -1 per century. We observed no significant change in pole declination over the period for which we have data. Applying our pole correction reduces the feature misregistration from tens of km to 3 km. Applying the spin rate and derivative corrections further reduces the misregistration to 1.2 km. ?? 2008. The American Astronomical Society. All rights reserved.

  5. Application of shuttle imaging radar to geologic mapping

    NASA Technical Reports Server (NTRS)

    Labotka, T. C.

    1986-01-01

    Images from the Shuttle Imaging Radar - B (SIR-B) experiment covering the area of the Panamint Mountains, Death Valley, California, were examined in the field and in the laboratory to determine their usefulness as aids for geologic mapping. The covered area includes the region around Wildrose Canyon where rocks ranging in age from Precambrian to Cenozoic form a moderately rugged portion of the Panamint Mountains, including sharp ridges, broad alluviated upland valleys, and fault-bounded grabens. The results of the study indicate that the available SIR-B images of this area primarily illustrate variations in topography, except in the broadly alluviated areas of Panamint Valley and Death Valley where deposits of differing reflectivity can be recognized. Within the mountainous portion of the region, three textures can be discerned, each representing a different mode of topographic expression related to the erosion characteristics of the underlying bedrock. Regions of Precambrian bedrock have smooth slopes and sharp ridges with a low density of gullies. Tertiary monolithologic breccias have smooth, steep slopes with an intermediate density of gullies with rounded ridges. Tertiary fanglomerates have steep rugged slopes with numerous steep-sided gullies and knife-sharp ridges. The three topographic types reflect the consistancy and relative susceptibility to erosion of the bedrock; the three types can readily be recognized on topographic maps. At present, it has not been possible to distinguish on the SIR-B image of the mountainous terrain the type of bedrock, independent of the topographic expression.

  6. Principles and applications of imaging radar. Manual of remote sensing: Third edition, Volume 2

    SciTech Connect

    Henderson, F.M.; Lewis, A.J.

    1998-12-31

    This second volume in the Third Edition of the Manual of Remote Sensing offers a current and comprehensive survey of the theory, methods, and applications of imaging radar for geoscientists, engineers and application scientists interested in the advantages of radar remote sensing. Produced under the auspices of the American Society for Photogrammetry and Remote Sensing, it brings together contributions from experts around the world to discuss the basic principles of imaging radars and trace the research activity--past, present, and future--across the many sciences where radar remote sensing may be applied. This book offers an invaluable snapshot of radar remote sensing technology, including radargrammetry, radar polarimetry and interferometry and its uses. It combines technical and procedural coverage of systems, data interpretation, and other fundamentals with generous coverage of practical applications in agriculture; forestry; soil moisture monitoring; geology; geomorphology and hydrology; oceanography; land use, land cover mapping and archeology.

  7. An image-based approach for classification of human micro-doppler radar signatures

    NASA Astrophysics Data System (ADS)

    Tivive, Fok Hing Chi; Phung, Son Lam; Bouzerdoum, Abdesselam

    2013-05-01

    With the advances in radar technology, there is an increasing interest in automatic radar-based human gait identification. This is because radar signals can penetrate through most dielectric materials. In this paper, an image-based approach is proposed for classifying human micro-Doppler radar signatures. The time-varying radar signal is first converted into a time-frequency representation, which is then cast as a two-dimensional image. A descriptor is developed to extract micro-Doppler features from local time-frequency patches centered along the torso Doppler frequency. Experimental results based on real data collected from a 24-GHz Doppler radar showed that the proposed approach achieves promising classification performance.

  8. Parameter estimation and imaging of moving targets in bistatic synthetic aperture radar

    NASA Astrophysics Data System (ADS)

    Li, Yu; Huang, Puming; Yang, Zhimei; Lin, Chenchen

    2016-01-01

    In high-resolution bistatic synthetic aperture radar (SAR) systems, parameter estimation is essential to moving target imaging quality. However, precise parameters are difficult to obtain without priori information due to the relative along-track and across-track velocities between the moving target and platforms that change with time. A parameter estimation and imaging approach for moving targets is proposed. First, slant range and relative velocities expression are deduced based on the geometry of bistatic SAR model with one stationary configuration. Then, range curvature term are compensated skillfully by fitting the range-compressed curve in two-dimensional time domain, meanwhile, the initial estimated range walk slope can be achieved. Finally, precise Doppler centroid is estimated through searching for the maximum contrast with folding search algorithm, which is giving consideration to both searching precision and computational complexity. Thus, the proposed algorithm provides an effective way for parameter estimation and imaging of moving target without prior information and interpolation operation. Experimental results show the effectiveness of the proposed method.

  9. A system for the real-time display of radar and video images of targets

    NASA Technical Reports Server (NTRS)

    Allen, W. W.; Burnside, W. D.

    1990-01-01

    Described here is a software and hardware system for the real-time display of radar and video images for use in a measurement range. The main purpose is to give the reader a clear idea of the software and hardware design and its functions. This system is designed around a Tektronix XD88-30 graphics workstation, used to display radar images superimposed on video images of the actual target. The system's purpose is to provide a platform for tha analysis and documentation of radar images and their associated targets in a menu-driven, user oriented environment.

  10. Experimental Investigations on the Distortion of ISAR Images Using Different Radar Waveforms

    DTIC Science & Technology

    2003-09-01

    Defence Research and Recherche et developpement Development Canada pour la defense Canada DEFENCE [ID7 E FENSE Experimental Investigations on the...image radar bidimensionnelle d’une cible en mouvement. En raison de sa capacit6 d’identifier les cibles en mouvement, le radar ISAR est un outil op ... rationnel int~ressant pour les syst~mes de surveillance radar, comme ceux qui sont instaiks A bord de l’avion de patrouille A long rayon d’action CP

  11. Optimum imaging time selection algorithm for inverse synthetic aperture radar images using geometric features and image gradient

    NASA Astrophysics Data System (ADS)

    Fulin, Su; Hongxin, Yang

    2016-07-01

    For better using of inverse synthetic aperture radar (ISAR) images of ship targets, it is more desirable to select a proper imaging time to obtain high quality top-view or side-view images. However, optimum imaging time selection is not robust enough for the restriction of traditional geometric feature extraction methods. In our study, we propose a method based on the geometric features and gradient maximization. First, we select the imaging instant from radar echoes by the centerline and mainmast of the ship. In this part, we propose a geometric features extraction method to improve the robustness of instant selection in different scenarios. Then, an image gradient maximization is employed to estimate the period for ISAR imaging. Finally, experimental results of both simulated and real signals are provided to demonstrate the effectiveness and practicability of the algorithm.

  12. Terahertz inverse synthetic aperture radar imaging using self-mixing interferometry with a quantum cascade laser.

    PubMed

    Lui, H S; Taimre, T; Bertling, K; Lim, Y L; Dean, P; Khanna, S P; Lachab, M; Valavanis, A; Indjin, D; Linfield, E H; Davies, A G; Rakić, A D

    2014-05-01

    We propose a terahertz (THz)-frequency synthetic aperture radar imaging technique based on self-mixing (SM) interferometry, using a quantum cascade laser. A signal processing method is employed which extracts and exploits the radar-related information contained in the SM signals, enabling the creation of THz images with improved spatial resolution. We demonstrate this by imaging a standard resolution test target, achieving resolution beyond the diffraction limit.

  13. Microwave penetration and attenuation in desert soil - A field experiment with the Shuttle Imaging Radar

    NASA Technical Reports Server (NTRS)

    Farr, T. G.; Elachi, C.; Hartl, P.; Chowdhury, K.

    1986-01-01

    Receivers buried in the Nevada desert were used with the Shuttle Imaging Radar to measure microwave attenuation as a function of soil moisture in situ. Results agree closely with laboratory measurements of attenuation and suggest that penetration of tens of centimeters in desert soils is common for L-band (1.2-GHz) radar.

  14. Applications of compressed sensing to coherent radar imaging

    NASA Astrophysics Data System (ADS)

    Zhu, Qian

    Although meteoroids fragmentation has been observed and studied in the optical meteor community since the 1950s, no definitive fragmentation mechanisms for the relatively small meteoroids (mass .10.4 kg) have been proposed. This is in part due to the lack of observations to constrain physical mechanisms of the fragmentation process. While it is challenging to record fragmentation in faint optical meteors, observing meteors using HPLA (High-Power, Large- Aperture) radars can yield considerable information especially when employing coherent radar imaging (CRI). CRI can potentially resolve the fragmentation process in three spatial dimensions by monitoring the evolution of the plasma in the meteor head-echo, flare-echo, and trail-echo regions. On the other hand, the emerging field of compressed sensing (CS) provides a novel paradigm for signal acquisition and processing. Furthermore, it has been, and continues to be, applied with great success in radar systems, offering various benefits such as better resolution compared to traditional techniques, reduced resource requirements, and so forth. In this dissertation, we examine how CS can be incorporated to improve the performance of CRI using HPLA radars. We propose a single CS-based formalism that enables the threedimensions (3D).the range, Doppler frequency, and cross range (represented by the direction cosines) domain.coherent imaging. We show that the CS-based CRI can not only reduce the system costs and decrease the needed number of baselines by spatial sparse sampling, which can be much less than the number required by Nyquist-Shannon sampling criterion, but also achieve high resolution for target detection. We implement the CS-based CRI for meteor studies with observations conducted at the Jicamarca Radio Observatory (JRO) in Peru. We present the unprecedented resolved details of meteoroids fragmentation, including both along and transverse to the trajectory spreading of the developing plasma, apparently caused by

  15. The influence of sensor and flight parameters on texture in radar images

    NASA Astrophysics Data System (ADS)

    Frost, V. S.; Shanmugan, K. S.; Holtzman, J. C.

    Texture is known to be important in the analysis of radar images for geologic applications. It was previously shown that texture features derived from the grey-level co-occurrence matrix (GLCM) can be used to separate large scale texture in radar images. The influence of sensor parameters, specifically the spatial and radiometric resolution and flight parameters, i.e., the orientation of the surface structure relative to the sensor, on the ability to classify texture based on the GLCM features is investigated. It was found that changing these sensor and flight parameters greatly affects the usefulness of the GLCM for classifying texture on radar images.

  16. The influence of sensor and flight parameters on texture in radar images

    NASA Technical Reports Server (NTRS)

    Frost, V. S.; Shanmugan, K. S.; Holtzman, J. C.

    1984-01-01

    Texture is known to be important in the analysis of radar images for geologic applications. It has previously been shown that texture features derived from the grey level co-occurrence matrix (GLCM) can be used to separate large scale texture in radar images. Here the influence of sensor parameters, specifically the spatial and radiometric resolution and flight parameters, i.e., the orientation of the surface structure relative to the sensor, on the ability to classify texture based on the GLCM features is investigated. It was found that changing these sensor and flight parameters greatly affects the usefulness of the GLCM for classifying texture on radar images.

  17. The Influence of Sensor and Flight Parameters on Texture in Radar Images

    NASA Technical Reports Server (NTRS)

    Frost, V. S.; Shanmugan, K. S.; Holtzman, J. C.

    1983-01-01

    Texture is known to be important in the analysis of radar images for geologic applications. It was previously shown that texture features derived from the grey-level co-occurrence matrix (GLCM) can be used to separate large scale texture in radar images. The influence of sensor parameters, specifically the spatial and radiometric resolution and flight parameters, i.e., the orientation of the surface structure relative to the sensor, on the ability to classify texture based on the GLCM features is investigated. It was found that changing these sensor and flight parameters greatly affects the usefulness of the GLCM for classifying texture on radar images.

  18. The influence of sensor and flight parameters on texture in radar images

    NASA Technical Reports Server (NTRS)

    Frost, V. S.; Shanmugan, K. S.; Holtzman, J. C.

    1983-01-01

    Texture is known to be important in the analysis of radar images for geologic applications. It has previously been shown that texture features derived from the grey level co-occurrence matrix (GLCM) can be used to separate large scale texture in radar images. Here the influence of sensor parameters, specifically the spatial and radiometric resolution and flight parameters, i.e., the orientation of the surface structure relative to the sensor, on the ability to classify texture based on the GLCM features is investigated. It was found that changing these sensor and flight parameters greatly affects the usefulness of the GLCM for classifying texture on radar images.

  19. A model for forming airborne synthetic aperture radar images of underground targets

    SciTech Connect

    Doerry, A.W.

    1994-01-01

    Synthetic Aperture Radar (SAR) from an airborne platform has been proposed for imaging targets beneath the earth`s surface. The propagation of the radar`s energy within the ground, however, is much different than in the earth`s atmosphere. The result is signal refraction, echo delay, propagation losses, dispersion, and volumetric scattering. These all combine to make SAR image formation from an airborne platform much more challenging than a surface imaging counterpart. This report treats the ground as a lossy dispersive half-space, and presents a model for the radar echo based on measurable parameters. The model is then used to explore various imaging schemes, and image properties. Dynamic range is discussed, as is the impact of loss on dynamic range. Modified window functions are proposed to mitigate effects of sidelobes of shallow targets overwhelming deeper targets.

  20. Seasat views North America, the Caribbean, and Western Europe with imaging radar

    NASA Technical Reports Server (NTRS)

    Ford, J. P.; Blom, R. G.; Bryan, M. L.; Daily, M.; Dixon, T. H.; Elachi, C.; Xenos, E. C.

    1980-01-01

    Forty-one digitally correlated Seasat synthetic-aperture radar images of land areas in North America, the Caribbean, and Western Europe are presented to demonstrate this microwave orbital imagery. The characteristics of the radar images, the types of information that can be extracted from them, and certain of their inherent distortions are briefly described. Each atlas scene covers an area of 90 X 90 kilometers, with the exception of the one that is the Nation's Capital. The scenes are grouped according to salient features of geology, hydrology and water resources, urban landcover, or agriculture. Each radar image is accompanied by a corresponding image in the optical or near-infrared range, or by a simple sketch map to illustrate features of interest. Characteristics of the Seasat radar imaging system are outlined.

  1. Quantitative blood flow velocity imaging using laser speckle flowmetry

    PubMed Central

    Nadort, Annemarie; Kalkman, Koen; van Leeuwen, Ton G.; Faber, Dirk J.

    2016-01-01

    Laser speckle flowmetry suffers from a debated quantification of the inverse relation between decorrelation time (τc) and blood flow velocity (V), i.e. 1/τc = αV. Using a modified microcirculation imager (integrated sidestream dark field - laser speckle contrast imaging [SDF-LSCI]), we experimentally investigate on the influence of the optical properties of scatterers on α in vitro and in vivo. We found a good agreement to theoretical predictions within certain limits for scatterer size and multiple scattering. We present a practical model-based scaling factor to correct for multiple scattering in microcirculatory vessels. Our results show that SDF-LSCI offers a quantitative measure of flow velocity in addition to vessel morphology, enabling the quantification of the clinically relevant blood flow, velocity and tissue perfusion. PMID:27126250

  2. Quantitative blood flow velocity imaging using laser speckle flowmetry

    NASA Astrophysics Data System (ADS)

    Nadort, Annemarie; Kalkman, Koen; van Leeuwen, Ton G.; Faber, Dirk J.

    2016-04-01

    Laser speckle flowmetry suffers from a debated quantification of the inverse relation between decorrelation time (τc) and blood flow velocity (V), i.e. 1/τc = αV. Using a modified microcirculation imager (integrated sidestream dark field - laser speckle contrast imaging [SDF-LSCI]), we experimentally investigate on the influence of the optical properties of scatterers on α in vitro and in vivo. We found a good agreement to theoretical predictions within certain limits for scatterer size and multiple scattering. We present a practical model-based scaling factor to correct for multiple scattering in microcirculatory vessels. Our results show that SDF-LSCI offers a quantitative measure of flow velocity in addition to vessel morphology, enabling the quantification of the clinically relevant blood flow, velocity and tissue perfusion.

  3. Moving target imaging using ultrawideband synthetic aperture radar

    NASA Astrophysics Data System (ADS)

    Guo, Hanwei; Liang, Diannong; Wan, Yan; Huang, Xiaotao; Dong, Zhen

    2003-09-01

    Moving Target High Resolution Imaging of Foliage Penetrate Ultra-Wide Band Synthetic Aperture Radar (FOPEN UWB SAR) is of great significance for battlefield awareness of concealed target. Great range migration and strong clutter make moving target detection and imaging difficult, especially the Signal to Clutter Ration(SCR) some times is so low that the moving targets is invisible in FOPEN UWB SAR imagery. To improve SCR, the clean technique is used in range compressed data domain. The clean technique and data reconstruction help single channel of FOPEN UWB SAR suppress strong tree clutter and stationary target signal from region of interest. A new definition called General Key-Stone Transform is given, which can correct any order of range migration. FOPEN UWB SAR has long integrated time. The plane and target moving in long time lead to complex range migration. To obtain high resolution imagery of moving target, General Key-Stone transform are applied to remove the range migration and realize multiple moving target data segment. Both General Key-Stone Transform and Clean Technique are applied in real data processing of FOPEN UWB SAR. The result shows that multiple moving targets in the trees are clearly detected and high resolution imagery is formed.

  4. Passive Synthetic Aperture Radar Imaging Using Commercial OFDM Communication Networks

    DTIC Science & Technology

    2012-09-13

    passive and non-passive radar scenarios, mostly geared towards radar detection and tracking radar functions. The goal of this research is to under- stand...it is this separation that allows extreme remote sensing applications like planetary surface observations using either receiver or transmitter...multicarrier ap- proach is geared towards UWB signals, where slow time differences in the subcarriers 26 phase history are exploitable. Other related work

  5. 3D measurements in the polar mesosphere using coherent radar imaging

    NASA Astrophysics Data System (ADS)

    Zecha, M.; Sommer, S.; Rapp, M.; Stober, G.; Latteck, R.

    2012-12-01

    Radars provide the opportunity of continuous measurements in the interesting area of the polar mesosphere. Usually the spatial resolution of measurements by pulsed VHF radars is limited by the radar beam width, transmitting pulse length, and sampling time. Due to these technical restrictions the typical small-scale structures in the mesosphere often cannot be resolved. Furthermore the quality of the estimation of dynamic atmosphere parameters is reduced if the position and direction of scatter returns cannot determined exactly. Radar interferometry methods have been developed to reduce these limitations. The coherent radar imaging method gives a high resolving image of the scatter structure insight the radar beam volume. In recent years the VHF radar MAARSY was installed in Andenes/Norway (69°N). This new radar was designed to allow improved three-dimensional observations in the atmosphere. It consists of 433 Yagis and allows a minimum beam width of about 4 degree. The beam direction can be changed pulse-by-pulse freely in azimuth angle and practicable up to 40 degree in zenith angle. The pulse length can be varied from a couple of km down to 50 m. Up to 16 receiving channels of spaced antennas can be used. In this presentation we show the detection of the angles-of-arrival of radar echoes and the correction of the wind measurements. We demonstrate the improvement of measurement results by using coherent radar imaging. The differences to the results of conventional methods depend on the beam width, range resolution, antenna distances, and beam tilting. We show that the application of interferometry is necessary to improve considerably the quality of 3D-measurement results. Furthermore we demonstrate the synthesis of high resolved images to get a real 3D image of the mesosphere.

  6. Standoff concealed weapon detection using a 350 GHz radar imaging system

    SciTech Connect

    Sheen, David M.; Hall, Thomas E.; Severtsen, Ronald H.; McMakin, Douglas L.; Hatchell, Brian K.; Valdez, Patrick LJ

    2010-04-01

    The Pacific Northwest National Laboratory is currently developing a 350 GHz, active, wideband, three-dimensional, radar imaging system to evaluate the feasibility of active sub-mm imaging for standoff concealed weapon detection. The prototype radar imaging system is based on a wideband, heterodyne, frequency-multiplier-based transceiver system coupled to a quasi-optical focusing system and high-speed rotating conical scanner. The wideband operation of this system provides accurate ranging information, and the images obtained are fully three-dimensional. Recent improvements to the system include increased imaging speed using improved balancing techniques, wider bandwidth, and image display techniques.

  7. 47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of an imaging system operating... section is limited to GPRs and wall imaging systems operated for purposes associated with law enforcement...) A GPR that is designed to be operated while being hand held and a wall imaging system shall...

  8. Space Radar Image of Death Valley in 3-D

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This picture is a three-dimensional perspective view of Death Valley, California. This view was constructed by overlaying a SIR-C radar image on a U.S. Geological Survey digital elevation map. The SIR-C image is centered at 36.629 degrees north latitude and 117.069 degrees west longitude. We are looking at Stove Pipe Wells, which is the bright rectangle located in the center of the picture frame. Our vantage point is located atop a large alluvial fan centered at the mouth of Cottonwood Canyon. In the foreground on the left, we can see the sand dunes near Stove Pipe Wells. In the background on the left, the Valley floor gradually falls in elevation toward Badwater, the lowest spot in the United States. In the background on the right we can see Tucki Mountain. This SIR-C/X-SAR supersite is an area of extensive field investigations and has been visited by both Space Radar Lab astronaut crews. Elevations in the Valley range from 70 meters (230 feet) below sea level, the lowest in the United States, to more than 3,300 meters (10,800 feet) above sea level. Scientists are using SIR-C/X-SAR data from Death Valley to help the answer a number of different questions about Earth's geology. One question concerns how alluvial fans are formed and change through time under the influence of climatic changes and earthquakes. Alluvial fans are gravel deposits that wash down from the mountains over time. They are visible in the image as circular, fan-shaped bright areas extending into the darker valley floor from the mountains. Information about the alluvial fans helps scientists study Earth's ancient climate. Scientists know the fans are built up through climatic and tectonic processes and they will use the SIR-C/X-SAR data to understand the nature and rates of weathering processes on the fans, soil formation and the transport of sand and dust by the wind. SIR-C/X-SAR's sensitivity to centimeter-scale (inch-scale) roughness provides detailed maps of surface texture. Such information

  9. Statement of capabilities: Micropower Impulse Radar (MIR) technology applied to mine detection and imaging

    SciTech Connect

    Azevedo, S.G.; Gavel, D.T.; Mast, J.E.; Warhus, J.P.

    1995-03-13

    The Lawrence Livermore National Laboratory (LLNL) has developed radar and imaging technologies with potential applications in mine detection by the armed forces and other agencies involved in demining efforts. These new technologies use a patented ultra-wideband (impulse) radar technology that is compact, low-cost, and low power. Designated as Micropower Impulse Radar, these compact, self-contained radars can easily be assembled into arrays to form complete ground penetrating radar imaging systems. LLNL has also developed tomographic reconstruction and signal processing software capable of producing high-resolution 2-D and 3-D images of objects buried in materials like soil or concrete from radar data. Preliminary test results have shown that a radar imaging system using these technologies has the ability to image both metallic and plastic land mine surrogate targets buried in 5 to 10 cm of moist soil. In dry soil, the system can detect buried objects to a depth of 30 cm and more. This report describes LLNL`s unique capabilities and technologies that can be applied to the demining problem.

  10. Synthetic aperture radar images of ocean waves, theories of imaging physics and experimental tests

    NASA Technical Reports Server (NTRS)

    Vesecky, J. F.; Durden, S. L.; Smith, M. P.; Napolitano, D. A.

    1984-01-01

    The physical mechanism for the synthetic Aperture Radar (SAR) imaging of ocean waves is investigated through the use of analytical models. The models are tested by comparison with data sets from the SEASAT mission and airborne SAR's. Dominant ocean wavelengths from SAR estimates are biased towards longer wavelengths. The quasispecular scattering mechanism agrees with experimental data. The Doppler shift for ship wakes is that of the mean sea surface.

  11. Imaging Buried Culverts Using Ground Penetrating Radar: Comparing 100 MHZ Through 1 GHZ Antennae

    NASA Astrophysics Data System (ADS)

    Abdul Aziz, A.; Stewart, R. R.; Green, S. L.

    2013-12-01

    *Aziz, A A aabdulaziz@uh.edu Allied Geophysical Lab, Department of Earth and Atmospheric Sciences, University of Houston, TX, USA Stewart, R R rrstewart@uh.edu Allied Geophysical Lab, Department of Earth and Atmospheric Sciences, University of Houston, TX, USA *Green, S L slgreen@yahoo.com Allied Geophysical Lab, Department of Earth and Atmospheric Sciences, University of Houston, TX, USA A 3D ground penetrating radar (GPR) survey, using three different frequency antennae, was undertaken to image buried steel culverts at the University of Houston's La Marque Geophysical Observatory 30 miles south of Houston, Texas. The four culverts, under study, support a road crossing one of the area's bayous. A 32 m by 4.5 m survey grid was designed on the road above the culverts and data were collected with 100 MHz, 250 MHz, and 1 GHz antennae. We used an orthogonal acquisition geometry for the three surveys. Inline sampling was from 1.0 cm to 10 cm (from 1 GHz to 100 MHz antenna) with inline and crossline spacings ranging from 0.2 m to 0.5 m. We used an initial velocity of 0.1 m/ns (from previous CMP work at the site) for the display purposes. The main objective of the study was to analyze the effect of different frequency antennae on the resultant GPR images. We are also interested in the accuracy and resolution of the various images, in addition to developing an optimal processing flow.The data were initially processed with standard steps that included gain enhancement, dewow and temporal-filtering, background suppression, and 2D migration. Various radar velocities were used in the 2D migration and ultimately 0.12 m/ns was used. The data are complicated by multipathing from the surface and between culverts (from modeling). Some of this is ameliorated via deconvolution. The top of each of the four culverts was evident in the GPR images acquired with the 250 MHz and 100 MHz antennas. For 1 GHz, the top of the culvert was not clear due to the signal's attenuation. The 250 MHz

  12. Imaging Spectroscopy of a Sunspot: Thermal and Velocity Structure

    NASA Astrophysics Data System (ADS)

    Balasubramaniam, K. S.

    2002-08-01

    The purpose of this paper is (1) to confirm and establish the working of a dual-etalon Fabry-Pérot imaging spectroscopy system at the National Solar Observatory/Sacramento Peak Dunn Solar Telescope and (2) to use this system to extend previous work by many authors and understand the structure and dynamics of sunspots. A detailed investigation of the thermal and velocity structure in an isolated sunspot, using the Fe I 5576 Å spectral line, is presented. The concept of flowless maps is incorporated, to separate velocity and intensity effects. The resulting intensities are used to generate thermal maps of the sunspot along the height of formation of a spectral line, followed by a thermal span map. The thermal span in penumbral regions is in the range of 1350-1580 K. It is a factor of 2 smaller in the umbra. Using spectral line bisectors, we extend the concept of a velocity span to a sunspot, following Gray. The velocity span is used to study the velocity gradients across a sunspot. The velocity span maximizes in the middle of the sunspot penumbra and falls off on either side. The Doppler-neutralized mean bisectors from the disk-side and limb-side penumbra show more sharply inclined gradients, when compared with the C-shaped photospheric bisectors. The mean umbral bisectors show sharp, <-shaped profiles. In most of the penumbra, the individual bisectors are sharply inclined, with a shape of ``/'' or ``\\,'' indicative of a highly suppressed convective flow. The intensity and velocity data show that a new family of penumbral filaments rises in the middle penumbra. Bisector intensity-velocity relationships display opposite gradients in the inner and outer penumbra, showing the rising and falling parts of curved penumbral flux tubes. Some clustering of the bisector intensity-velocity relationship is perhaps due to the fluted nature of flux tubes.

  13. Convective cloud vertical velocity and mass-flux characteristics from radar wind profiler observations during GoAmazon2014/5: VERTICAL VELOCITY GOAMAZON2014/5

    SciTech Connect

    Giangrande, Scott E.; Toto, Tami; Jensen, Michael P.; Bartholomew, Mary Jane; Feng, Zhe; Protat, Alain; Williams, Christopher R.; Machado, Luiz

    2016-11-15

    A radar wind profiler data set collected during the 2 year Department of Energy Atmospheric Radiation Measurement Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) campaign is used to estimate convective cloud vertical velocity, area fraction, and mass flux profiles. Vertical velocity observations are presented using cumulative frequency histograms and weighted mean profiles to provide insights in a manner suitable for global climate model scale comparisons (spatial domains from 20 km to 60 km). Convective profile sensitivity to changes in environmental conditions and seasonal regime controls is also considered. Aggregate and ensemble average vertical velocity, convective area fraction, and mass flux profiles, as well as magnitudes and relative profile behaviors, are found consistent with previous studies. Updrafts and downdrafts increase in magnitude with height to midlevels (6 to 10 km), with updraft area also increasing with height. Updraft mass flux profiles similarly increase with height, showing a peak in magnitude near 8 km. Downdrafts are observed to be most frequent below the freezing level, with downdraft area monotonically decreasing with height. Updraft and downdraft profile behaviors are further stratified according to environmental controls. These results indicate stronger vertical velocity profile behaviors under higher convective available potential energy and lower low-level moisture conditions. Sharp contrasts in convective area fraction and mass flux profiles are most pronounced when retrievals are segregated according to Amazonian wet and dry season conditions. During this deployment, wet season regimes favored higher domain mass flux profiles, attributed to more frequent convection that offsets weaker average convective cell vertical velocities.

  14. Spaceborne weather radar

    NASA Technical Reports Server (NTRS)

    Meneghini, Robert; Kozu, Toshiaki

    1990-01-01

    The present work on the development status of spaceborne weather radar systems and services discusses radar instrument complementarities, the current forms of equations for the characterization of such aspects of weather radar performance as surface and mirror-image returns, polarimetry, and Doppler considerations, and such essential factors in spaceborne weather radar design as frequency selection, scanning modes, and the application of SAR to rain detection. Attention is then given to radar signal absorption by the various atmospheric gases, rain drop size distribution and wind velocity determinations, and the characteristics of clouds, as well as the range of available estimation methods for backscattering, single- and dual-wavelength attenuation, and polarimetric and climatological characteristics.

  15. Ground-Truth Observations of Ice-Covered North Slope Lakes Imaged by Radar

    DTIC Science & Technology

    1981-10-01

    published by the American Society for Testing and Materi- als, 1916 Race St., Philadelphia, Pa. 19103. Cover: Radar image of the north coast of Alaska...truth observations of ice-covered North Slope lakes imaged by radar W.F. Weeks, A.J. Cow and R.J. Schertler J October 1981 ’AA Prepared for OCEAN...PROCESSES BRANCH NATIONAL AERONAUTICS AND SPACE ADMINISTRATION By UNITED STATES ARMY CORPS OF ENGINEERS COLD REGIONS RESEARCH AND ENGINEERING LABORATORY

  16. Terahertz Inverse Synthetic Aperture Radar (ISAR) Imaging With a Quantum Cascade Laser Transmitter

    DTIC Science & Technology

    2010-01-01

    Terahertz inverse synthetic aperture radar ( ISAR ) imaging with a quantum cascade laser transmitter Andriy A. Danylov1,*, Thomas M. Goyette1...COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE Terahertz inverse synthetic aperture radar ( ISAR ) imaging with a quantum cascade laser...band ISAR Imagery of Scale-Model Tactical Targets Using a 1.56 THz Compact Range," Proc. SPIE 5095, 66-74 (2003). 10. M. J. Coulombe, T. Horgan, J

  17. High-resolution imaging using a wideband MIMO radar system with two distributed arrays.

    PubMed

    Wang, Dang-wei; Ma, Xiao-yan; Chen, A-Lei; Su, Yi

    2010-05-01

    Imaging a fast maneuvering target has been an active research area in past decades. Usually, an array antenna with multiple elements is implemented to avoid the motion compensations involved in the inverse synthetic aperture radar (ISAR) imaging. Nevertheless, there is a price dilemma due to the high level of hardware complexity compared to complex algorithm implemented in the ISAR imaging system with only one antenna. In this paper, a wideband multiple-input multiple-output (MIMO) radar system with two distributed arrays is proposed to reduce the hardware complexity of the system. Furthermore, the system model, the equivalent array production method and the imaging procedure are presented. As compared with the classical real aperture radar (RAR) imaging system, there is a very important contribution in our method that the lower hardware complexity can be involved in the imaging system since many additive virtual array elements can be obtained. Numerical simulations are provided for testing our system and imaging method.

  18. Monsoon flood boundary delineation and damage assessment using space borne imaging radar and Landsat data

    NASA Technical Reports Server (NTRS)

    Imhoff, Marc L.; Vermillion, C.; Story, M. H.; Choudhury, A. M.; Gafoor, A.

    1987-01-01

    Space-borne synthetic aperture radar (SAR) data acquired by the Shuttle Imaging Radar-B (SIR-B) Program and Landsat Multispectral Scanner Subsystem (MSS) Data from Landsat 4 were used to map flood boundaries for the assessment of flood damage in the Peoples Republic of Bangladesh. The cloud penetrating capabilities of the L-band radar provided a clear picture of the hydrologic conditions of the surface during a period of inclement weather at the end of the wet phase of the 1984 monsoon. The radar image data were digitally processed to geometrically rectify the pixel geometry and were filtered to subdue radar image speckle effects. Contrast enhancement techniques and density slicing were used to create discrete land-cover categories corresponding to surface conditions present at the time of the Shuttle overflight. The radar image classification map was digitally registered to a spectral signature classification map of the area derived from Landsat MSS data collected two weeks prior to the SIR-B mission. Classification accuracy comparisons were made between the radar and MSS classification maps, and flood boundary and flood damage assessment measurements were made with the merged data by adding the classifications and inventorying the land-cover classes inundated at the time of flooding.

  19. Talemzane - Algerian impact crater detected on SIR-A orbital imaging radar

    NASA Technical Reports Server (NTRS)

    Mchone, John F.; Greeley, Ronald

    1987-01-01

    In November, 1981, NASA's first Shuttle Imaging Radar mission (SIR-A) began producing maplike photographic strips of Earth scenes from orbital altitude. A Saharan radar image acquired over Algeria clearly delineates two sedimentary basins, Erg Occidental and Erg Oriental, separated by an elongated zone of exposed bedrock, the M'Zab Chebka. At the NE margin of the Chebka, rimrocks, slopes, and ejecta deposits of Talemzane meteorite impact crater appear as a distinct two km wide radar-bright ring. This unique circle of strong radar backscatter distinguishes the solitary impact structure from numerous dayas (similarly appearing karstic depressions) which characterize the region. The crater is prominent on radar, but is obscure on optically obtained satellite and aircraft images, as are partly buried fluvial drainage systems and fault-block traces developed in bedrocks of the Chebka. Radar detection of an annular drainage system indicates possible presence of a ring graben at the crater. Brightest radar signals on the image are cultural features at recently developed gas fields near Hassi er R'Mel.

  20. Synthetic aperture radar target detection, feature extraction, and image formation techniques

    NASA Technical Reports Server (NTRS)

    Li, Jian

    1994-01-01

    This report presents new algorithms for target detection, feature extraction, and image formation with the synthetic aperture radar (SAR) technology. For target detection, we consider target detection with SAR and coherent subtraction. We also study how the image false alarm rates are related to the target template false alarm rates when target templates are used for target detection. For feature extraction from SAR images, we present a computationally efficient eigenstructure-based 2D-MODE algorithm for two-dimensional frequency estimation. For SAR image formation, we present a robust parametric data model for estimating high resolution range signatures of radar targets and for forming high resolution SAR images.

  1. Synthetic aperture radar target detection, feature extraction, and image formation techniques

    NASA Astrophysics Data System (ADS)

    Li, Jian

    1994-09-01

    This report presents new algorithms for target detection, feature extraction, and image formation with the synthetic aperture radar (SAR) technology. For target detection, we consider target detection with SAR and coherent subtraction. We also study how the image false alarm rates are related to the target template false alarm rates when target templates are used for target detection. For feature extraction from SAR images, we present a computationally efficient eigenstructure-based 2D-MODE algorithm for two-dimensional frequency estimation. For SAR image formation, we present a robust parametric data model for estimating high resolution range signatures of radar targets and for forming high resolution SAR images.

  2. Registration of partially overlapping laser-radar range images

    NASA Astrophysics Data System (ADS)

    Lv, Dan; Sun, Jian-Feng; Li, Qi; Wang, Qi

    2015-10-01

    To register partially overlapping three-dimensional point sets from different viewpoints, it is necessary to remove spurious corresponding point pairs that are not located in overlapping regions. Most variants of the iterative closest point (ICP) algorithm require users to manually select the rejection parameters for discarding spurious point pairs between the registering views. This requirement often results in unreliable and inaccurate registration. To overcome this problem, we present an improved ICP algorithm that can automatically determine the rejection percentage to reliably and accurately align partially overlapping laser-radar (ladar) range images. The similarity of k neighboring features of each nonplanar point is employed to determine reasonable point pairs in nonplanar regions, and the distance measurement method is used to find reasonable point pairs in planar regions. The rejection percentage can be obtained from these two sets of reasonable pairs. The performance of our algorithm is compared with that of five other algorithms using various models with low and high curvatures. The experimental results show that our algorithm is more accurate and robust than the other algorithms.

  3. Microwave Imaging Radar Reflectometer System Utilizing Digital Beam Forming

    NASA Astrophysics Data System (ADS)

    Hu, Fengqi; Li, Meijiao; Domier, Calvin W.; Liu, Xiaoguang; Luhmann, Neville C., Jr.

    2016-10-01

    Microwave Imaging Reflectometry is a radar-like technique developed to measure the electron density fluctuations in fusion plasmas. Phased Antenna Arrays can serve as electronically controlled ``lenses'' that can generate the required wavefronts by phase shifting and amplitude scaling, which is being realized in the digital domain with higher flexibility and faster processing speed. In the transmitter, the resolution of the phase control is 1.4 degrees and the amplitude control is 0.5 dB/ step. A V-band double-sided, printed bow tie antenna which exhibits 49% bandwidth (46 - 76 GHz) is employed. The antenna is fed by a microstrip transmission line for easy impedance matching. The simple structure and the small antenna are suitable for low cost fabrication, easy circuit integration, and phased antenna array multi-frequency applications. In the receiver part, a sub-array of 32 channels with 200 mil spacing is used to collect the scattered reflected signal from one unit spot on the plasma cutoff surface. Pre-amplification is used to control the noise level of the system and wire bondable components are used to accommodate the small spacing between each channel. After down converting, base band signals are digitized and processed in an FPGA module. U.S. Department of Energy Grant No. DE-FG02-99ER54531.

  4. 2-D Drift Velocities from the IMAGE EUV Plasmaspheric Imager

    NASA Technical Reports Server (NTRS)

    Gallagher, D.; Adrian, M.

    2007-01-01

    The IMAGE Mission extreme ultraviolet imager (EUY) observes He+ plasmaspheric ions throughout the inner magnetosphere. Limited by ionizing radiation and viewing close to the Sun, images of the He+ distribution are available every 10 minutes for many hours as the spacecraft passes through apogee in its highly elliptical orbit. As a consistent constituent at about 15%, He+ is an excellent surrogate for monitoring all of the processes that control the dynamics of plasmaspheric plasma. In particular, the motion ofHe+ transverse to the ambient magnetic field is a direct indication of convective electric fields. The analysis of boundary motions has already achieved new insights into the electrodynamic coupling processes taking place between energetic magnetospheric plasmas and the ionosphere. Yet to be fulfilled, however, is the original promise that global EUY images of the plasmasphere might yield two-dimensional pictures of meso-scale to macro-scale electric fields in the inner magnetosphere. This work details the technique and initial application of an IMAGE EUY analysis that appears capable of following thermal plasma motion on a global basis.

  5. Potential for observing and discriminating impact craters and comparable volcanic landforms on Magellan radar images

    NASA Technical Reports Server (NTRS)

    Ford, J. P.

    1989-01-01

    Observations of small terrestrial craters by Seasat synthetic aperture radar (SAR) at high resolution (approx. 25 m) and of comparatively large Venusian craters by Venera 15/16 images at low resolution (1000 to 2000 m) and shorter wavelength show similarities in the radar responses to crater morphology. At low incidence angles, the responses are dominated by large scale slope effects on the order of meters; consequently it is difficult to locate the precise position of crater rims on the images. Abrupt contrasts in radar response to changing slope (hence incidence angle) across a crater produce sharp tonal boundaries normal to the illumination. Crater morphology that is radially symmetrical appears on images to have bilateral symmetry parallel to the illumination vector. Craters are compressed in the distal sector and drawn out in the proximal sector. At higher incidence angles obtained with the viewing geometry of SIR-A, crater morphology appears less compressed on the images. At any radar incidence angle, the distortion of a crater outline is minimal across the medial sector, in a direction normal to the illumination. Radar bright halos surround some craters imaged by SIR-A and Venera 15 and 16. The brightness probably denotes the radar response to small scale surface roughness of the surrounding ejecta blankets. Similarities in the radar responses of small terrestrial impact craters and volcanic craters of comparable dimensions emphasize the difficulties in discriminating an impact origin from a volcanic origin in the images. Similar difficulties will probably apply in discriminating the origin of small Venusian craters, if they exist. Because of orbital considerations, the nominal incidence angel of Magellan radar at the center of the imaging swath will vary from about 45 deg at 10 deg N latitude to about 16 deg at the north pole and at 70 deg S latitude. Impact craters and comparable volcanic landforms will show bilateral symmetry parallel to the illumination

  6. Moving target detection in foliage using along track monopulse synthetic aperture radar imaging.

    PubMed

    Soumekh, M

    1997-01-01

    This paper presents a method for detecting moving targets embedded in foliage from the monostatic and bistatic synthetic aperture radar (SAR) data obtained via two airborne radars. The two radars, which are mounted on the same aircraft, have different coordinates in the along track (cross-range) domain. However, unlike the interferometric SAR systems used for topographic mapping, the two radars possess a common range and altitude (i.e., slant range). The resultant monopulse SAR images are used to construct difference and interferometric images for moving target detection. It is shown that the signatures of the stationary targets are weakened in these images. Methods for estimating a moving target's motion parameters are discussed. Results for an ultrawideband UHF SAR system are presented.

  7. Visualizing characteristics of ocean data collected during the Shuttle Imaging Radar-B experiment

    NASA Technical Reports Server (NTRS)

    Tilley, David G.

    1991-01-01

    Topographic measurements of sea surface elevation collected by the Surface Contour Radar (SCR) during NASA's Shuttle Imaging Radar (SIR-B) experiment are plotted as three dimensional surface plots to observe wave height variance along the track of a P-3 aircraft. Ocean wave spectra were computed from rotating altimeter measurements acquired by the Radar Ocean Wave Spectrometer (ROWS). Fourier power spectra computed from SIR-B synthetic aperture radar (SAR) images of the ocean are compared to ROWS surface wave spectra. Fourier inversion of SAR spectra, after subtraction of spectral noise and modeling of wave height modulation, yields topography similar to direct measurements made by SCR. Visual perspectives on the SCR and SAR ocean data are compared. Threshold distinctions between surface elevation and texture modulations of SAR data are considered within the context of a dynamic statistical model of rough surface scattering. The result of these endeavors is insight as to the physical mechanism governing the imaging of ocean waves with SAR.

  8. Drumlin fields and glaciated mountains - A contrast in geomorphic perception from Seasat radar images

    NASA Technical Reports Server (NTRS)

    Ford, J. P.

    1981-01-01

    Digitally correlated Seasat synthetic-aperture radar (SAR) images of the Alaska Range, Alaska, and the drumlin-drift belt in Ireland are analyzed for the perception and identification of geomorphic features. The two terrains display strongly contrasted types of glacial topography whose identification in each case is related to the geometry of the Seasat imaging radar. Identification of terrain shape and form is important within the caveats imposed by the intrinsic distortions on the radar images. Image texture serves coarsely to distinguish topography. Image tones are scene-dependent and do not uniquely identify specific targets. Extensive alignments of linear and curvilinear features provide some of the more important image information from which to make geologic interpretations in each case.

  9. Three-dimensional ground penetrating radar imaging using multi-frequency diffraction tomography

    SciTech Connect

    Mast, J.E.; Johansson, E.M.

    1994-11-15

    In this talk we present results from a three-dimensional image reconstruction algorithm for impulse radar operating in monostatic pule-echo mode. The application of interest to us is the nondestructive evaluation of civil structures such as bridge decks. We use a multi-frequency diffraction tomography imaging technique in which coherent backward propagations of the received reflected wavefield form a spatial image of the scattering interfaces within the region of interest. This imaging technique provides high-resolution range and azimuthal visualization of the subsurface region. We incorporate the ability to image in planarly layered conductive media and apply the algorithm to experimental data from an offset radar system in which the radar antenna is not directly coupled to the surface of the region. We present a rendering in three-dimensions of the resulting image data which provides high-detail visualization.

  10. Three-dimensional ground penetrating radar imaging using multi-frequency diffraction tomography

    SciTech Connect

    Mast, J.E.; Johansson, E.M.

    1994-07-01

    In this paper we present results from a three-dimensional image reconstruction algorithm for impulse radar operating in monostatic pulse-echo mode. The application of interest to us is the nondestructive evaluation of civil structures such as bridge decks. We use a multi-frequency diffraction tomography imaging technique in which coherent backward propagations of the received reflected wavefield form a spatial image of the scattering interfaces within the region of interest. This imaging technique provides high-resolution range and azimuthal visualization of the subsurface region. We incorporate the ability to image in planarly layered conductive media and apply the algorithm to experimental data from an offset radar system in which the radar antenna is not directly coupled to the surface of the region. We present a rendering in three-dimensions of the resulting image data which provides high-detail visualization.

  11. Forward Looking Radar Imaging by Truncated Singular Value Decomposition and Its Application for Adverse Weather Aircraft Landing.

    PubMed

    Huang, Yulin; Zha, Yuebo; Wang, Yue; Yang, Jianyu

    2015-06-18

    The forward looking radar imaging task is a practical and challenging problem for adverse weather aircraft landing industry. Deconvolution method can realize the forward looking imaging but it often leads to the noise amplification in the radar image. In this paper, a forward looking radar imaging based on deconvolution method is presented for adverse weather aircraft landing. We first present the theoretical background of forward looking radar imaging task and its application for aircraft landing. Then, we convert the forward looking radar imaging task into a corresponding deconvolution problem, which is solved in the framework of algebraic theory using truncated singular decomposition method. The key issue regarding the selecting of the truncated parameter is addressed using generalized cross validation approach. Simulation and experimental results demonstrate that the proposed method is effective in achieving angular resolution enhancement with suppressing the noise amplification in forward looking radar imaging.

  12. Forward Looking Radar Imaging by Truncated Singular Value Decomposition and Its Application for Adverse Weather Aircraft Landing

    PubMed Central

    Huang, Yulin; Zha, Yuebo; Wang, Yue; Yang, Jianyu

    2015-01-01

    The forward looking radar imaging task is a practical and challenging problem for adverse weather aircraft landing industry. Deconvolution method can realize the forward looking imaging but it often leads to the noise amplification in the radar image. In this paper, a forward looking radar imaging based on deconvolution method is presented for adverse weather aircraft landing. We first present the theoretical background of forward looking radar imaging task and its application for aircraft landing. Then, we convert the forward looking radar imaging task into a corresponding deconvolution problem, which is solved in the framework of algebraic theory using truncated singular decomposition method. The key issue regarding the selecting of the truncated parameter is addressed using generalized cross validation approach. Simulation and experimental results demonstrate that the proposed method is effective in achieving angular resolution enhancement with suppressing the noise amplification in forward looking radar imaging. PMID:26094627

  13. Radar principles

    NASA Technical Reports Server (NTRS)

    Sato, Toru

    1989-01-01

    Discussed here is a kind of radar called atmospheric radar, which has as its target clear air echoes from the earth's atmosphere produced by fluctuations of the atmospheric index of refraction. Topics reviewed include the vertical structure of the atmosphere, the radio refractive index and its fluctuations, the radar equation (a relation between transmitted and received power), radar equations for distributed targets and spectral echoes, near field correction, pulsed waveforms, the Doppler principle, and velocity field measurements.

  14. Obtaining anisotropic velocity data for proper depth seismic imaging

    SciTech Connect

    Egerev, Sergey; Yushin, Victor; Ovchinnikov, Oleg; Dubinsky, Vladimir; Patterson, Doug

    2012-05-24

    The paper deals with the problem of obtaining anisotropic velocity data due to continuous acoustic impedance-based measurements while scanning in the axial direction along the walls of the borehole. Diagrams of full conductivity of the piezoceramic transducer were used to derive anisotropy parameters of the rock sample. The measurements are aimed to support accurate depth imaging of seismic data. Understanding these common anisotropy effects is important when interpreting data where it is present.

  15. Velocity map ion imaging study of Ar2+ photodissociation

    NASA Astrophysics Data System (ADS)

    Maner, J. A.; Mauney, D. T.; Duncan, M. A.

    2017-03-01

    The argon dimer cation is produced in a plasma generated by a laser spark in a supersonic expansion. The cold ions are mass selected and investigated by photodissociation at 355 nm, with velocity map imaging of the Ar+ photofragment. Using the radius of the image, we determine the kinetic energy release and derive the ground state dissociation energy of Ar2+ as D0″ = 1.32 +0.03/-0.02 eV. Additionally, the angular distribution is described with β = 1.71-1.95, consistent with excitation of the parallel-type 2Σg+ ← 2Σu+ transition.

  16. Change detection in synthetic aperture radar images based on image fusion and fuzzy clustering.

    PubMed

    Gong, Maoguo; Zhou, Zhiqiang; Ma, Jingjing

    2012-04-01

    This paper presents an unsupervised distribution-free change detection approach for synthetic aperture radar (SAR) images based on an image fusion strategy and a novel fuzzy clustering algorithm. The image fusion technique is introduced to generate a difference image by using complementary information from a mean-ratio image and a log-ratio image. In order to restrain the background information and enhance the information of changed regions in the fused difference image, wavelet fusion rules based on an average operator and minimum local area energy are chosen to fuse the wavelet coefficients for a low-frequency band and a high-frequency band, respectively. A reformulated fuzzy local-information C-means clustering algorithm is proposed for classifying changed and unchanged regions in the fused difference image. It incorporates the information about spatial context in a novel fuzzy way for the purpose of enhancing the changed information and of reducing the effect of speckle noise. Experiments on real SAR images show that the image fusion strategy integrates the advantages of the log-ratio operator and the mean-ratio operator and gains a better performance. The change detection results obtained by the improved fuzzy clustering algorithm exhibited lower error than its preexistences.

  17. Shuttle Imaging Radar-A (SIR-A) experiment

    NASA Technical Reports Server (NTRS)

    Elachi, C. (Editor); Cimino, J. B. (Editor)

    1982-01-01

    The SIR-A experiment was conducted in order to acquire radar data over a variety of regions to further understanding of the radar signatures of various geologic features. The capability of the Shuttle as a scientific platform for observation of the Earth's resources was assessed. The SIR-A sensor operated nominally and the full data acquisition capacity of the optical recorder was used.

  18. Radar image processing module development program, phase 3

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The feasibility of using charge coupled devices in an IPM for processing synthetic aperture radar signals onboard the NASA Convair 990 (CV990) aircraft was demonstrated. Radar data onboard the aircraft was recorded and processed using a CCD sampler and digital tape recorder. A description of equipment and testing was provided. The derivation of the digital presum filter was documented. Photographs of the sampler/tape recorder, real time display and circuit boards in the IPM were also included.

  19. Instantaneous velocity field imaging instrument for supersonic reacting flows

    NASA Technical Reports Server (NTRS)

    Allen, M. G.; Davis, S. J.; Kessler, W. J.; Legner, H. H.; Mcmanus, K. R.; Mulhall, P. A.; Parker, T. E.; Sonnenfroh, D. M.

    1993-01-01

    The technical tasks conducted to develop and demonstrate a new gas velocity measurement technique for high enthalpy reacting flows is described. The technique is based on Doppler-shifted Planar Laser-induced Fluorescence (PLIF) imaging of the OH radical. The imaging approach permits, in principle, single-shot measurements of the 2-D distribution of a single velocity component in the measurement plane, and is thus a technique of choice for applications in high enthalpy transient flow facilities. In contrast to previous work in this area, the present program demonstrated an approach which modified the diagnostic technique to function under the constraints of practical flow conditions of engineering interest, rather than vice-versa. In order to accomplish the experimental demonstrations, the state-of-the-art in PLIF diagnostic techniques was advanced in several ways. Each of these tasks is described in detail and is intended to serve as a reference in supporting the transition of this new capability to the fielded PLIF instruments now installed at several national test facilities. Among the new results of general interest in LlF-based flow diagnostics, a detailed set of the first measurements of the collisional broadening and shifting behavior of OH (1,0) band transitions in H7-air combustion environments is included. Such measurements are critical in the design of a successful strategy for PLIF velocity imaging; they also relate to accurate concentration and temperature measurements, particularly in compressible flow regimes. Furthermore, the results shed new light on the fundamental relationship between broadening and energy transfer collisions in OH A(sup 2)Sigma(+)v(sup ') = 1. The first single-pulse, spectrally-resolved measurements of the output of common pulsed dye lasers were also produced during the course of this effort. As with the OH broadening measurements, these data are a significant aspect of a successful velocity imaging strategy, and also have

  20. Revolutionising incoherent scatter science with EISCAT_3D: A European three-dimensional imaging radar for atmospheric and geospace research

    NASA Astrophysics Data System (ADS)

    Turunen, Esa; McCrea, Ian; Kosch, Mike

    2010-05-01

    EISCAT_3D will be Europe's next-generation radar for the study of the high-latitude atmosphere and geospace, located in northern Fenno-Scandinavia, with capabilities going well beyond anything currently available to the international research community. The facility will consist of several very large active phased-array antenna transmitters/receivers, and multiple passive sites located in three countries. Depending on the available funding, EISCAT_3D will be comprised of tens of thousands, up to more than 100 000, individual antenna elements. EISCAT_3D combines several key attributes which have never before been available together in a single radar, such as volumetric imaging and tracking, aperture synthesis imaging, multistatic configuration, improved sensitivity and transmitter flexibility. The use of advanced beam-forming technology allows the beam direction to be switched in milliseconds, rather than the minutes which it can take to re-position dish-based radars. This allows very wide spatial coverage to be obtained, by interleaving multiple beam directions to carry out quasi-simultaneous volumetric imaging. It also allows objects such as satellites and space debris to be tracked across the sky. At the passive sites, the design allows for at least five simultaneous beams at full bandwidth, rising to over twenty beams if the bandwidth is limited to the ion line, allowing the whole range of the transmitted beam to be imaged from each passive site, using holographic radar techniques. EISCAT_3D has a modular configuration, which allows an active array to be split into smaller elements to be used for aperture synthesis imaging. The result will be an entirely new data product, consisting of range-dependent images of small sub-beamwidth scale structures, with sizes down to 20 m. EISCAT_3D will be the first phased array incoherent scatter radar to use a multistatic configuration. A minimum of five radar sites, consisting of two pairs located around 120 km and 250 km

  1. Informational Analysis for Compressive Sampling in Radar Imaging

    PubMed Central

    Zhang, Jingxiong; Yang, Ke

    2015-01-01

    Compressive sampling or compressed sensing (CS) works on the assumption of the sparsity or compressibility of the underlying signal, relies on the trans-informational capability of the measurement matrix employed and the resultant measurements, operates with optimization-based algorithms for signal reconstruction and is thus able to complete data compression, while acquiring data, leading to sub-Nyquist sampling strategies that promote efficiency in data acquisition, while ensuring certain accuracy criteria. Information theory provides a framework complementary to classic CS theory for analyzing information mechanisms and for determining the necessary number of measurements in a CS environment, such as CS-radar, a radar sensor conceptualized or designed with CS principles and techniques. Despite increasing awareness of information-theoretic perspectives on CS-radar, reported research has been rare. This paper seeks to bridge the gap in the interdisciplinary area of CS, radar and information theory by analyzing information flows in CS-radar from sparse scenes to measurements and determining sub-Nyquist sampling rates necessary for scene reconstruction within certain distortion thresholds, given differing scene sparsity and average per-sample signal-to-noise ratios (SNRs). Simulated studies were performed to complement and validate the information-theoretic analysis. The combined strategy proposed in this paper is valuable for information-theoretic orientated CS-radar system analysis and performance evaluation. PMID:25811226

  2. Studies of Velocity Fluctuations in the Lower Atmosphere Using the MU Radar. Part 1. Azimuthal Anisotropy

    DTIC Science & Technology

    1990-01-01

    max mna relative it north.q,’ is not plotted "lihen a, - 0.2. 1 hCSe q uantities are runninge ascr-P.s oxver I h plotted ec CN 4 min. �l. Cos cos x...1atioo4hrc1eghs Scheler . A. 0.. and C. H. L~iu, 1988: T he effects of Doppler shift on (an . P/i’ . 8. 141-I481.the gravity wase spectra ohs-ned b%. MST radar

  3. Estimating the Effective Permittivity for Reconstructing Accurate Microwave-Radar Images

    PubMed Central

    Lavoie, Benjamin R.; Okoniewski, Michal; Fear, Elise C.

    2016-01-01

    We present preliminary results from a method for estimating the optimal effective permittivity for reconstructing microwave-radar images. Using knowledge of how microwave-radar images are formed, we identify characteristics that are typical of good images, and define a fitness function to measure the relative image quality. We build a polynomial interpolant of the fitness function in order to identify the most likely permittivity values of the tissue. To make the estimation process more efficient, the polynomial interpolant is constructed using a locally and dimensionally adaptive sampling method that is a novel combination of stochastic collocation and polynomial chaos. Examples, using a series of simulated, experimental and patient data collected using the Tissue Sensing Adaptive Radar system, which is under development at the University of Calgary, are presented. These examples show how, using our method, accurate images can be reconstructed starting with only a broad estimate of the permittivity range. PMID:27611785

  4. Time-lapse imaging of human heart motion with switched array UWB radar.

    PubMed

    Brovoll, Sverre; Berger, Tor; Paichard, Yoann; Aardal, Øyvind; Lande, Tor Sverre; Hamran, Svein-Erik

    2014-10-01

    Radar systems for detection of human heartbeats have mostly been single-channel systems with limited spatial resolution. In this paper, a radar system for ultra-wideband (UWB) imaging of the human heart is presented. To make the radar waves penetrate the human tissue the antenna is placed very close to the body. The antenna is an array with eight elements, and an antenna switch system connects the radar to the individual elements in sequence to form an image. Successive images are used to build up time-lapse movies of the beating heart. Measurements on a human test subject are presented and the heart motion is estimated at different locations inside the body. The movies show rhythmic motion consistent with the beating heart, and the location and shape of the reflections correspond well with the expected response form the heart wall. The spatial dependent heart motion is compared to ECG recordings, and it is confirmed that heartbeat modulations are seen in the radar data. This work shows that radar imaging of the human heart may provide valuable information on the mechanical movement of the heart.

  5. Retrieval of Raindrop Size Distribution, Vertical Air Velocity and Water Vapor Attenuation Using Dual-Wavelength Doppler Radar Observations

    NASA Technical Reports Server (NTRS)

    Heymsfield, Gerald M.; Tian, Lin; Li, Lihua; Srivastava, C.

    2005-01-01

    Two techniques for retrieving the slope and intercept parameters of an assumed exponential raindrop size distribution (RSD), vertical air velocity, and attenuation by precipitation and water vapor in light stratiform rain using observations by airborne, nadir looking dual-wavelength (X-band, 3.2 cm and W-band, 3.2 mm) radars are presented. In both techniques, the slope parameter of the RSD and the vertical air velocity are retrieved using only the mean Doppler velocities at the two wavelengths. In the first method, the intercept of the RSD is estimated from the observed reflectivity at the longer wavelength assuming no attenuation at that wavelength. The attenuation of the shorter wavelength radiation by precipitation and water vapor are retrieved using the observed reflectivity at the shorter wavelength. In the second technique, it is assumed that the longer wavelength suffers attenuation only in the melting band. Then, assuming a distribution of water vapor, the melting band attenuation at both wavelengths and the rain attenuation at the shorter wavelength are retrieved. Results of the retrievals are discussed and several physically meaningful results are presented.

  6. 4D Surface Velocity Fields of Rutford Ice Stream, West Antarctica, Inferred From Continuous Synthetic Aperture Radar Observations

    NASA Astrophysics Data System (ADS)

    Minchew, B. M.; Simons, M.; Riel, B. V.; Milillo, P.

    2015-12-01

    The mechanics of West Antarctic Ice Sheet (WAIS) beds impose fundamental constraints on ice flow and help set the timescale of potential WAIS collapse. Understanding basal mechanics requires a variety of observational and modeling approaches, among them using synoptic-scale observations of surface velocities as constraints on numerical ice flow models. This approach has been developed and employed over the past few decades using available surface velocity data, which often amount to snapshots of ice flow at sporadic times. The next major step in the evolution of geodetic methods for glacier dynamics is capturing synoptic-scale, time-dependent ice-flow characteristics. Here, using spatially and temporally dense synthetic aperture radar (SAR) observations, we extend to the time domain existing methods for inferring velocity fields in three spatial dimensions from SAR and optical data. Our approach yields some of the first-ever truly 4D velocity fields. We briefly outline the underlying methodology before detailing the resulting velocity fields, which consist of a mean velocity vector, a user-defined set of temporal functions, and a DEM correction factor. Rutford Ice Stream (RIS), WAIS, provides an ideal proof-of-concept location because of its strong, well-documented, tidal-timescale ice flow variations. Existing GPS observations of RIS ice flow constrain the dominant periods of sinusoidal ice flow variability, which we use to define a set of sinusoidal functions used in the 4D velocity fields. COSMO-SkyMed, a 4-satellite constellation, collected SAR data for approximately 9 months beginning in late summer 2013 at sampling rates sufficient to distinguish the primary periods of tidally induced ice flow variability. The results, obtained using more than 1000 SAR-derived displacement fields, provide a map-view of tidally induced flow variations and tidal-timescale grounding line migration that indicate greater spatial heterogeneity in the response of the ice stream to

  7. Water detection in thermal insulating materials by high resolution imaging with holographic radar

    NASA Astrophysics Data System (ADS)

    Capineri, L.; Falorni, P.; Becthel, T.; Ivashov, S.; Razevig, V.; Zhuravlev, A.

    2017-01-01

    The present research is aimed at the application of high resolution holographic images for the detection and characterization of low water content (0.2-1 g) water patches in insulating materials. The images acquired with manual scanning with high frequency (7 GHz) holographic radar with I/Q outputs are compared with a high speed electromechanical scanner with 4 GHz holographic radar. Small patches of the order of 22 mm  ×  22 mm buried at 18 mm into insulating materials with a low dielectric constant, have been accurately reconstructed with the high frequency holographic radar but they can also be detected with the lower frequency holographic radar at even greater depths.

  8. Analysis of the Gran Desierto, Pinacte Region, Sonora, Mexico, via shuttle imaging radar

    NASA Technical Reports Server (NTRS)

    Greeley, R.; Christensen, P. R.; Mchone, J. F