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Sample records for airborne interferometric sar

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  3. Foliage problem in interferometric SAR

    NASA Astrophysics Data System (ADS)

    Rogers, George W.; Mansfield, Arthur W.; Roth, Duane; Poehler, Paul L.; Rais, Houra

    1999-08-01

    Interferometric SAR exploits the coherent nature of multiple synthetic aperture radar images to recover phase (range difference) information and thence terrain evaluation data as well as other phase derivative products such as Coherent Change Detection (CCD). Of the numerous factors that can degrade the coherency of multiple SAR collections, foliage constitutes one of the most challenging. The foliage problem in IFSAR is discussed and an airborne multiple pass collection is used to illustrate some facets of the problem. Resolution as a variable in the tradeoff between the bias and variance of the interferogram is discussed in the context of the example.

  4. Registration of interferometric SAR images

    NASA Technical Reports Server (NTRS)

    Lin, Qian; Vesecky, John F.; Zebker, Howard A.

    1992-01-01

    Interferometric synthetic aperture radar (INSAR) is a new way of performing topography mapping. Among the factors critical to mapping accuracy is the registration of the complex SAR images from repeated orbits. A new algorithm for registering interferometric SAR images is presented. A new figure of merit, the average fluctuation function of the phase difference image, is proposed to evaluate the fringe pattern quality. The process of adjusting the registration parameters according to the fringe pattern quality is optimized through a downhill simplex minimization algorithm. The results of applying the proposed algorithm to register two pairs of Seasat SAR images with a short baseline (75 m) and a long baseline (500 m) are shown. It is found that the average fluctuation function is a very stable measure of fringe pattern quality allowing very accurate registration.

  5. Interferometric SAR to EO image registration problem

    NASA Astrophysics Data System (ADS)

    Rogers, George W.; Mansfield, Arthur W.; Rais, Houra

    2000-08-01

    Historically, SAR to EO registration accuracy has been at the multiple pixel level compared to sub-pixel EO to EO registration accuracies. This is due to a variety of factors including the different scattering characteristics of the ground for EO and SAR, SAR speckle, and terrain induced geometric distortion. One approach to improving the SAR to EO registration accuracy is to utilize the full information from multiple SAR surveys using interferometric techniques. In this paper we will examine this problem in detail with an example using ERS SAR imagery. Estimates of the resulting accuracy based on ERS are included.

  6. PHARUS airborne SAR concept

    NASA Astrophysics Data System (ADS)

    Snoeij, Paul; Pouwels, Henk; Koomen, Peter J.; Hoogeboom, Peter

    1995-11-01

    PHARUS (phased array universal SAR) is an airborne SAR concept which is being developed in the Netherlands. The PHARUS system differs from other airborne SARs by the use of a phased array antenna, which provides both for the flexibility in the design as well as for a compact, light-weight instrument that can be carried on small aircraft. The concept allows for the construction of airborne SAR systems on a common generic basis but tailored to specific user needs and can be seen as a preparation for future spaceborne SAR systems using solid state transmitters with electronically steerable phased array antenna. The whole approach is aimed at providing an economic and yet technically sophisticated solution to remote sensing or surveying needs of a specific user. The solid state phased array antenna consists of a collection of radiating patches; the design flexibility for a large part resides in the freedom to choose the number of patches, and thereby the essential radar performance parameters such as resolution and swath width. Another consequence of the use of the phased array antenna is the system's compactness and the possibility to rigidly mount it on a small aircraft. The use of small aircraft of course considerably improves the cost/benefit ratio of the use of airborne SAR. Flight altitude of the system is flexible between about 7,000 and 40,000 feet, giving much operational freedom within the meteo and airspace control limits. In the PHARUS concept the airborne segment is complemented by a ground segment, which consists of a SAR processor, possibly extended by a matching image processing package. (A quick look image is available in real-time on board the aircraft.) The SAR processor is UNIX based and runs on easily available hardware (SUN station). Although the additional image processing software is available, the SAR processing software is nevertheless designed to be able to interface with commercially available image processing software, as well as being able

  7. Interferometric SAR imaging by transmitting stepped frequency chaotic noise signals

    NASA Astrophysics Data System (ADS)

    Zhang, Yunhua; Gu, Xiang; Zhai, Wenshuai; Dong, Xiao; Shi, Xiaojin; Kang, Xueyan

    2015-10-01

    Noise radar has been applied in many fields since it was proposed more than 50 years ago. However, it has not been applied to interferometric SAR imaging yet as far as we know. This paper introduces our recent work on interferometric noise radar. An interferometric SAR system was developed which can transmit both chirp signal and chaotic noise signal (CNS) at multiple carrier frequencies. An airborne experiment with this system by transmitting both signals was carried out, and the data were processed to show the capability of interferometric SAR imaging with CNS. The results shows that although the interferometric phase quality of CNS is degraded due to the signal to noise ratio (SNR) is lower compared with that of chirp signal, we still can get satisfied DEM after multi-looking processing. Another work of this paper is to apply compressed sensing (CS) theory to the interferometric SAR imaging with CNS. The CS theory states that if a signal is sparse, then it can be accurately reconstructed with much less sampled data than that regularly required according to Nyquist Sampling Theory. To form a structured random matrix, if the transmitted signal is of fixed waveform, then random subsampling is needed. However, if the transmitted signal is of random waveform, then only uniform subsampling is needed. This is another advantage of noise signal. Both the interferometric phase images and the DEMs by regular method and by CS method are processed with results compared. It is shown that the degradation of interferometric phases due to subsampling is larger than that of amplitude image.

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  9. Airborne Radar Interferometric Repeat-Pass Processing

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  10. Interferometric SAR coherence classification utility assessment

    SciTech Connect

    Yocky, D.A.

    1998-03-01

    The classification utility of a dual-antenna interferometric synthetic aperture radar (IFSAR) is explored by comparison of maximum likelihood classification results for synthetic aperture radar (SAR) intensity images and IPSAR intensity and coherence images. The addition of IFSAR coherence improves the overall classification accuracy for classes of trees, water, and fields. A threshold intensity-coherence classifier is also compared to the intensity-only classification results.

  11. New approaches in interferometric SAR data processing

    NASA Technical Reports Server (NTRS)

    Lin, Qian; Vesecky, John F.; Zebker, Howard A.

    1992-01-01

    It is well established that interferometric synthetic aperture radar (SAR) images can be inverted to perform surface elevation mapping. Among the factors critical to the mapping accuracy are registration of the interfering SAR images and phase unwrapping. A novel registration algorithm is presented that determines the registration parameters through optimization. A new figure of merit is proposed that evaluates the registration result during the optimization. The phase unwrapping problem is approached through a new method involving fringe line detection. The algorithms are tested with two SEASAT SAR images of terrain near Yellowstone National Park. These images were collected on Seasat orbits 1334 and 1420, which were very close together in space, i.e., less than 100 m. The resultant elevation map is compared with the USGS digital terrain elevation model.

  12. Using APES for interferometric SAR imaging.

    PubMed

    Palsetia, M R; Li, J

    1998-01-01

    We present an adaptive finite impulse response (FIR) filtering approach, which is referred to as the Amplitude and Phase EStimation (APES) algorithm, for interferometric synthetic aperture radar (SAR) imaging. We compare the APES algorithm with other FIR filtering approaches including the Capon and fast Fourier transform (FFT) methods. We show via both numerical and experimental examples that the adaptive FIR filtering approaches such as Capon and APES can yield more accurate spectral estimates with much lower sidelobes and narrower spectral peaks than the FFT method. We show that although the APES algorithm yields somewhat wider spectral peaks than the Capon method, the former gives more accurate overall spectral estimates and SAR images than the latter and the FFT method.

  13. Calibration of airborne SAR interferograms using multisquint-processed image pairs

    NASA Astrophysics Data System (ADS)

    Prats, Pau; Mallorqui, Jordi J.; Reigber, Andreas; Broquetas, Antoni

    2004-01-01

    This paper presents two different approaches to detect and correct phase errors appearing in interferometric airborne SAR sensors due to the lack of precision in the navigation system. The first one is intended for interferometric pairs with high coherence, and the second one for low coherent ones. Both techniques are based on a multisquint processing approach, i.e., by processing the same image pairs with different squint angles we can combine the information of different interferograms to obtain the desired phase correction. Airborne single- and repeat-pass interferometric data from the Deutsches Zentrum fur Luft- und Raumfahrt (DLR) Experimental airborne SAR is used to validate the method.

  14. Using APES for interferometric SAR imaging

    NASA Astrophysics Data System (ADS)

    Li, Jian; Palsetia, Marzban

    1996-06-01

    In this paper, we present an adaptive FIR filtering approach, which is referred to as the APES (amplitude and phase estimation of a sinusoid) algorithm, for interferometric SAR imaging. We apply the APES algorithm on the data obtained from two vertically displaced apertures of a SAR system to obtain the complex amplitude and the phase difference estimates, which are proportional to the radar cross section and the height of the scatterer, respectively, at the frequencies of interest. We also demonstrate how the APES algorithm can be applied to data matrices with large dimensions without incurring high computational overheads. We compare the APES algorithm with other FIR filtering approaches including the Capon and FFT methods. We show via both numerical and experimental examples that the adaptive FIR filtering approaches such as Capon and APES can yield more accurate spectral estimates with much lower sidelobes and narrower spectral peaks than the FFT method. We show that although the APES algorithm yields somewhat wider spectral peaks than the Capon method, the former gives more accurate overall spectral estimates and SAR images than the latter and the FFT method.

  15. Calibration of the Geosar Dual Frequency Interferometric SAR

    NASA Technical Reports Server (NTRS)

    Chapine, Elaine

    1999-01-01

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

  16. A comparison of interferometric SAR antenna options

    NASA Astrophysics Data System (ADS)

    Doerry, A. W.; Bickel, D. L.

    2013-05-01

    Interferometric Synthetic Aperture Radar (IFSAR or InSAR) uses multiple antenna phase centers to ultimately measure target scene elevation. Its ability to do so depends on the antenna configuration, and how the multiple phase centers are employed. We examine several different dual-phase-center antenna configurations and modalities, including a conventional arrangement where a dedicated antenna is used to transmit and receive with another to receive only, a configuration where transmit and receive operations are ping-ponged between phase centers, a monopulse configuration, and an orthogonal waveform configuration. Our figure of merit is the RMS height noise in the elevation estimation. We show that a monopulse configuration is equivalent to the ping-pong scheme, and both offer an advantage over the conventional arrangement. The orthogonal waveform offers the best potential performance, if sufficient isolation can be achieved.

  17. Two microstrip arrays for interferometric SAR applications

    NASA Technical Reports Server (NTRS)

    Huang, J.

    1993-01-01

    Two types of C-band aircraft interferometric Synthetic Aperture Radar (SAR) are being developed at JPL to measure the ocean wave characteristics. Each type requires two identical antennas with each having a long rectangular aperture to radiate fan-shaped beam(s). One type of these radars requires each of its antennas to radiate a broadside beam that will measure the target's cross-track velocity. The other type, having each of its antennas to radiate two off-broadside pointed beams, will allow the measurement of both the cross-track and the along-track velocities of the target. Because flush mounting of the antenna on the aircraft fuselage is desirable, microstrip patch array is selected for these interferometric SAR antennas. To meet the radar system requirement, each array needs a total of 76 microstrip patches which are arranged in a 38 x 2 rectangular aperture with a physical size of 1.6m x 16.5cm. To minimize the insertion loss and physical real estate of this relatively long array, a combined series/parallel feed technique is used. Techniques to suppress cross-pol radiation and to effectively utilize the RF power are also implemented. Cross-pol level of lower than -30 dB from the co-pol peak and low insertion loss of 0.36 dB have been achieved for both types of arrays. For the type of radar that requires two off-braodside pointed beams, a simple phasing technique is used to achieve this dual-beam capability with adequate antenna gain (20 dBi) and sidelobe level (-14 dB). Both radar arrays have been flight tested on aircraft with excellent antenna performance demonstrated.

  18. Process for combining multiple passes of interferometric SAR data

    DOEpatents

    Bickel, Douglas L.; Yocky, David A.; Hensley, Jr., William H.

    2000-11-21

    Interferometric synthetic aperture radar (IFSAR) is a promising technology for a wide variety of military and civilian elevation modeling requirements. IFSAR extends traditional two dimensional SAR processing to three dimensions by utilizing the phase difference between two SAR images taken from different elevation positions to determine an angle of arrival for each pixel in the scene. This angle, together with the two-dimensional location information in the traditional SAR image, can be transformed into geographic coordinates if the position and motion parameters of the antennas are known accurately.

  19. Integrated Data Processing Methodology for Airborne Repeat-pass Differential SAR Interferometry

    NASA Astrophysics Data System (ADS)

    Dou, C.; Guo, H.; Han, C.; Yue, X.; Zhao, Y.

    2014-11-01

    Short temporal baseline and multiple ground deformation information can be derived from the airborne differential synthetic aperture radar Interforemetry (D-InSAR). However, affected by the turbulence of the air, the aircraft would deviate from the designed flight path with high frequent vibrations and changes both in the flight trajectory and attitude. Restricted by the accuracy of the position and orientation system (POS), these high frequent deviations can not be accurately reported, which would pose great challenges in motion compensation and interferometric process. Thus, these challenges constrain its wider applications. The objective of this paper is to investigate the accurate estimation and compensation of the residual motion errors in the airborne SAR imagery and time-varying baseline errors between the diffirent data acquirations, furthermore, to explore the integration data processing theory for the airborne D-InSAR system, and thus help to accomplish the correct derivation of the ground deformation by using the airborne D-InSAR measurements.

  20. Airborne SAR/IFSAR for mapping in urban areas

    NASA Astrophysics Data System (ADS)

    Chayakula, Thongthit

    There are many problems in topographic mapping in an urban area. Traditional land survey is a very time consuming technique and can be very expensive. Photogrammetry is a popular choice but there are some problems such as clouds and limited operational time. Since Synthetic Aperture Radar, (SAR), is an active remote sensing system and its signal can penetrate through clouds, it can be operated at any time of day and is a independent of the weather. SAR could be a good solution for topographic mapping in an urban area. Combining SAR data and Interferometric radar technology can provide enough information for topographic mapping. Information can be extracted from SAR intensity Image. This thesis focuses on feature extraction and classification for topographic mapping in an urban area from airborne interferometric SAR data. A new algorithm is described which is simple and practical but yet very efficient for feature extraction and for object-based feature classification. An adapted Canny-Petrou-Kittler algorithm is applied for edge detection. Since the algorithm provides good detection, good localization and only one response to a single edge, it is an ideal edge detection for dense urban areas. Since the SAR image is noisy by its nature, small weak edges are expected. The modified non-maximal technique is also proposed to reduce unwanted edge. The technique of generation of bald earth DEM is proposed to obtain a normalised DEM for feature extraction. Region growing from edge detection is then applied to extract a more accurate shape of the feature and generate feature surface by using topographic parameters. The extracted feature is then classified by object-oriented classification technique, in which the classification is performed at object level not pixel level. And at the end of the process 3D city model can be produced.

  1. Implementation of SAR interferometric map generation using parallel processors

    SciTech Connect

    Doren, N.; Wahl, D.E.

    1998-07-01

    Interferometric fringe maps are generated by accurately registering a pair of complex SAR images of the same scene imaged from two very similar geometries, and calculating the phase difference between the two images by averaging over a neighborhood of pixels at each spatial location. The phase difference (fringe) map resulting from this IFSAR operation is then unwrapped and used to calculate the height estimate of the imaged terrain. Although the method used to calculate interferometric fringe maps is well known, it is generally executed in a post-processing mode well after the image pairs have been collected. In that mode of operation, there is little concern about algorithm speed and the method is normally implemented on a single processor machine. This paper describes how the interferometric map generation is implemented on a distributed-memory parallel processing machine. This particular implementation is designed to operate on a 16 node Power-PC platform and to generate interferometric maps in near real-time. The implementation is able to accommodate large translational offsets, along with a slight amount of rotation which may exist between the interferometric pair of images. If the number of pixels in the IFSAR image is large enough, the implementation accomplishes nearly linear speed-up times with the addition of processors.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  3. Study of a passive companion microsatellite to the SAOCOM-1B satellite of Argentina, for bistatic and interferometric SAR applications

    NASA Astrophysics Data System (ADS)

    Barbier, Christian; Derauw, Dominique; Orban, Anne; Davidson, Malcolm W. J.

    2014-10-01

    We report the results of a preparatory study aimed at exploring candidate applications that could benefit from a passive micro-satellite accompanying the L-band SAOCOM-1B satellite of Argentina, and to carry out a limited demonstration, based on data acquired during ESA airborne campaigns, of selected applications. In a first step of the study, the potential applications were identified and prioritized based on the mission context and strategic applications, scientific need, and feasibility. The next step of the study was to carry out some demonstrations using data sets acquired during the BioSAR 2007-2009, TropiSAR 2009 and IceSAR 2007 campaigns. A P-band InSAR digital elevation model was generated from BioSAR 2007 data. Time-series of interferometric coherence maps were obtained as a tool for change detection and monitoring. PolInSAR processing was carried out on BioSAR 2007 and IceSAR data.

  4. Mapping Slumgullion Landslide in Colorado, USA Using Airborne Repeat-Pass InSAR

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    Interferometric Synthetic Aperture Radar (InSAR) uses two or more SAR images over the same area to determine landscape topography or ground deformation. An interferogram, generated by the phase components of two coherent SAR images, depicts range changes between the radar and the ground resolution elements, and can be used to derive both landscape topography and subtle changes in surface elevation. However, spaceborne repeat-pass interferometry has two main drawbacks: effects due to differences in atmospheric temperature, pressure, and water vapour at two observation times, and loss of coherence due to long spatial and temporal baselines between observations. Airborne repeat-pass interferometry does not suffer from these drawbacks. The atmospheric effect in case of airborne DInSAR becomes negligible due to smaller swath coverage, and the coherence can be maintained by using smaller spatial and temporal baselines. However, the main technical limitation concerning airborne DInSAR is the need of precise motion compensation with an accurate navigation system to correct for the significant phase errors due to typical flight instability from air turbulence. Here, we present results from a pilot study conducted on July 2015 using both X-band and L-band SlimSAR airborne system over the Slumgullion landslide in Colorado in order to (1) acquire the differential interferograms from the airborne platform, (2) understand their source of errors, and (3) pave a way to improve the precision of the derived surface deformation. The landslide movement estimated from airborne DInSAR is also compared with coincident GPS, terrestrial laser scanning (TLS), airborne LiDAR, and spaceborne DInSAR measurements using COSMO-SkyMed images. The airborne DInSAR system has a potential to provide time-transient variability in land surface topography with high-precision and high-resolution, and provide researchers with greater flexibility in selecting the temporal and spatial baselines of the data

  5. BioSAR Airborne Biomass Sensing System

    SciTech Connect

    Graham, R.L.; Johnson, P.

    2007-05-24

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

  6. Preprocessing of SAR interferometric data using anisotropic diffusion filter

    NASA Astrophysics Data System (ADS)

    Sartor, Kenneth; Allen, Josef De Vaughn; Ganthier, Emile; Tenali, Gnana Bhaskar

    2007-04-01

    The most commonly used smoothing algorithms for complex data processing are blurring functions (i.e., Hanning, Taylor weighting, Gaussian, etc.). Unfortunately, the filters so designed blur the edges in a Synthetic Aperture Radar (SAR) scene, reduce the accuracy of features, and blur the fringe lines in an interferogram. For the Digital Surface Map (DSM) extraction, the blurring of these fringe lines causes inaccuracies in the height of the unwrapped terrain surface. Our goal here is to perform spatially non-uniform smoothing to overcome the above mentioned disadvantages. This is achieved by using a Complex Anisotropic Non-Linear Diffuser (CANDI) filter that is a spatially varying. In particular, an appropriate choice of the convection function in the CANDI filter is able to accomplish the non-uniform smoothing. This boundary sharpening intra-region smoothing filter acts on interferometric SAR (IFSAR) data with noise to produce an interferogram with significantly reduced noise contents and desirable local smoothing. Results of CANDI filtering will be discussed and compared with those obtained by using the standard filters on simulated data.

  7. First Demonstration of Agriculture Height Retrieval with PolInSAR Airborne Data

    NASA Astrophysics Data System (ADS)

    Lopez-Sanchez, Juan M.; Ballester-Berman, J. David; Hajnsek, Irena

    2011-03-01

    A set of three quad-pol images acquired at L-band in interferometric repeat-pass mode by DLR with the E-SAR system, in parallel with the AgriSAR2006 campaign, have been used to provide a first demonstration with airborne data of the retrieval of vegetation height from agricultural crops by means of PolInSAR based techniques.We have obtained accurate estimates of vegetation height over winter rape and maize fields, when compared with the availabe ground measurements. The same procedure yields a clear overestimation and larger variance over wheat fields.Results demonstrate that, although the frequency band is low, the model employed for the inversion is very simple, and the backscattered signal contains an important contribution from the ground, the volume information provided by interferometry is present and enables the application of PolInSAR-based retrieval approaches for agriculture monitoring practices.

  8. ScanSAR interferometric processing using existing standard InSAR software for measuring large scale land deformation

    NASA Astrophysics Data System (ADS)

    Liang, Cunren; Zeng, Qiming; Jia, Jianying; Jiao, Jian; Cui, Xi'ai

    2013-02-01

    Scanning synthetic aperture radar (ScanSAR) mode is an efficient way to map large scale geophysical phenomena at low cost. The work presented in this paper is dedicated to ScanSAR interferometric processing and its implementation by making full use of existing standard interferometric synthetic aperture radar (InSAR) software. We first discuss the properties of the ScanSAR signal and its phase-preserved focusing using the full aperture algorithm in terms of interferometry. Then a complete interferometric processing flow is proposed. The standard ScanSAR product is decoded subswath by subswath with burst gaps padded with zero-pulses, followed by a Doppler centroid frequency estimation for each subswath and a polynomial fit of all of the subswaths for the whole scene. The burst synchronization of the interferometric pair is then calculated, and only the synchronized pulses are kept for further interferometric processing. After the complex conjugate multiplication of the interferometric pair, the residual non-integer pulse repetition interval (PRI) part between adjacent bursts caused by zero padding is compensated by resampling using a sinc kernel. The subswath interferograms are then mosaicked, in which a method is proposed to remove the subswath discontinuities in the overlap area. Then the following interferometric processing goes back to the traditional stripmap processing flow. A processor written with C and Fortran languages and controlled by Perl scripts is developed to implement these algorithms and processing flow based on the JPL/Caltech Repeat Orbit Interferometry PACkage (ROI_PAC). Finally, we use the processor to process ScanSAR data from the Envisat and ALOS satellites and obtain large scale deformation maps in the radar line-of-sight (LOS) direction.

  9. Advanced SAR simulator with multi-beam interferometric capabilities

    NASA Astrophysics Data System (ADS)

    Reppucci, Antonio; Márquez, José; Cazcarra, Victor; Ruffini, Giulio

    2014-10-01

    State of the art simulations are of great interest when designing a new instrument, studying the imaging mechanisms due to a given scenario or for inversion algorithm design as they allow to analyze and understand the effects of different instrument configurations and targets compositions. In the framework of the studies about a new instruments devoted to the estimation of the ocean surface movements using Synthetic Aperture Radar along-track interferometry (SAR-ATI) an End-to-End simulator has been developed. The simulator, built in a high modular way to allow easy integration of different processing-features, deals with all the basic operations involved in an end to end scenario. This includes the computation of the position and velocity of the platform (airborne/spaceborne) and the geometric parameters defining the SAR scene, the surface definition, the backscattering computation, the atmospheric attenuation, the instrument configuration, and the simulation of the transmission/reception chains and the raw data. In addition, the simulator provides a inSAR processing suit and a sea surface movement retrieval module. Up to four beams (each one composed by a monostatic and a bistatic channel) can be activated. Each channel provides raw data and SLC images with the possibility of choosing between Strip-map and Scansar modes. Moreover, the software offers the possibility of radiometric sensitivity analysis and error analysis due atmospheric disturbances, instrument-noise, interferogram phase-noise, platform velocity and attitude variations. In this paper, the architecture and the capabilities of this simulator will be presented. Meaningful simulation examples will be shown.

  10. Preliminary analysis results of the Sea Surface Observation by a High Resolution Along-Track Interferometric SAR

    NASA Astrophysics Data System (ADS)

    Kojima, S.

    2013-12-01

    There are many requirements to detect the moving targets such as cars and ships in SAR images as well as to measure their speed. In particular, there are strongly requirements to detect ships and measure the ocean waves and the sea surface currents regardless of the time or the weather in the case of the ship accidents or the oil spill accidents because the rescue operation should be operated at the anytime. To satisfy these requirements, NICT developed the airborne along-track interferometric SAR (AT-InSAR) system in 2011. Kojima[1][2] carried out the preliminary experiments using a truck and ship to check its function and clarify its capability for the detection of the moving targets, and confirmed that its performance was satisfied with its specifications. The purpose of this study is to make clear the relationship between the phenomena on the sea surface such as the ocean waves and the velocity estimated from the AT-InSAR data, and the capability of the sea surface measurement by the AT-InSAR. In addition, the method to estimate wave directional spectra from AT-InSAR data is developed. The sea surface observation was carried out 3 km off the coast of Ooarai, the northeast of Tokyo, JAPAN on the 23th of August 2011. I observed the sea surface in the fine special resolution (0.3 m) and took a special average (1 m) to reduce noise. First of all, I estimated the wave velocity from the AT-InSAR images and calculated the 2D wave number spectra from it. And then, I estimated the directional wave spectra using the dispersion relation. As a result, it was clarified that the ocean waves could be measured by the AT-InSAR. In addition, it made clear that the bow waves and stern waves generated by a running ship could be detected by AT-InSAR. References [1] S. Kojima, T. Umehara, J. Uemoto, T. Kobayashi, M. Satake and S. Uratsuka, 'Development of Pi-SAR2 Along-Track Interferometric SAR System', IGARSS 2013, pp. 3159-3162, Aug. 2013. [2] S. Kojima, 'Evaluation of the Ship

  11. CARABAS - an airborne VHF SAR system

    SciTech Connect

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

    1996-11-01

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

  12. Moving from Temporal Coherence to Decorrelation Time of Interferometric Measurements Exploiting ESA's SAR Archive

    NASA Astrophysics Data System (ADS)

    Foumelis, Michael; Mitraka, Zina; Cuccu, Roberto; Desnos, Yves-Louis; Engdahl, Marcus

    2015-05-01

    Interferometric coherence can be considered as an expression of temporal decorrelation. It is understood that interferometric coherence decreases with time between SAR acquisitions because of changes in surface reflectivity, reducing the quality of SAR phase measurements. This is an intrinsic characteristic of the design of SAR systems that has a significant contribution at longer time scales. Although in the past there was not sufficient amount of SAR data to extract robust statistical metrics for decorrelation, in the present study it is demonstrated that tailored analysis of interferometric coherence exploiting the large SAR archive available by the European Space Agency (ESA), enables the accurate quantification of temporal decorrelation. A methodology to translate the observed rate of coherence loss into decorrelation times over a volcanic landscape, namely the Santorini volcanic complex is the subject treated in this study. Specifically, a sensitivity analysis was performed on a large data stack of interferometric pairs to quantify at a pixel level the time beyond which the interferometric phase becomes practically unusable due to the effect of decorrelation. Though the dependence of decorrelation on various land cover/use types is already documented the provision of additional information regarding the expected time of decorrelation is of practical use especially when EO data are utilized in operational activities. The performed analysis is viewed within the improved capacity of current and future SAR systems, while underlining the necessity for exploitation of archive data.

  13. Biomass estimation in a tropical wet forest using Fourier transforms of profiles from lidar or interferometric SAR

    NASA Astrophysics Data System (ADS)

    Treuhaft, R. N.; Gonçalves, F. G.; Drake, J. B.; Chapman, B. D.; dos Santos, J. R.; Dutra, L. V.; Graça, P. M. L. A.; Purcell, G. H.

    2010-12-01

    Tropical forest biomass estimation based on the structure of the canopy is a burgeoning and crucial remote sensing capability for balancing terrestrial carbon budgets. This paper introduces a new approach to structural biomass estimation based on the Fourier transform of vertical profiles from lidar or interferometric SAR (InSAR). Airborne and field data were used from 28 tropical wet forest stands at La Selva Biological Station, Costa Rica, with average biomass of 229 Mg-ha-1. RMS scatters of remote sensing biomass estimates about field measurements were 58.3 Mg-ha-1, 21%, and 76.1 Mg-ha-1, 26%, for lidar and InSAR, respectively. Using mean forest height, the RMS scatter was 97 Mg-ha-1, ≈34% for both lidar and InSAR. The confidence that Fourier transforms are a significant improvement over height was >99% for lidar and ≈90% for InSAR. Lidar Fourier transforms determined the useful range of vertical wavelengths to be 14 m to 100 m.

  14. Temporal Coherence as an Estimate of Decorrelation Time of SAR Interferometric Measurements

    NASA Astrophysics Data System (ADS)

    Foumelis, Michael

    2014-05-01

    Following a plethora of validations and demonstrations Interferometric SAR (InSAR) has been established as a mature space geodetic technique for providing valuable insights for various phenomena related to geohazards. One of the main advantages of space borne SAR systems with respect to GNSS is the continuous spatial coverage. However, the impact of temporal decorrelation especially in repeat-pass interferometry has been observed during the historical development of InSAR applications. Interferometric coherence is considered as the expression of temporal decorrelation. It is understood that interferometric coherence decreases with time between SAR acquisitions because of changes in surface reflectivity, reducing the accuracy and spatial coverage of SAR phase measurements. This is an intrinsic characteristic of the design of SAR systems that has a significant contribution at longer time scales. Since the majority of geohazards rely on long term observation scenarios, the effect of temporal decorrelation is evident as coherence becomes dominated by temporal changes. Although in the past there was not sufficient amount of SAR data to extract robust statistical metrics, in the present study it is demonstrated that tailored analysis of interferometric coherence by exploiting the large archive of SAR data available by the European Space Agency (ESA), enables the accurate quantification of temporal decorrelation. A methodology to translate the observed rate of coherence loss into decorrelation times over a volcanic landscape is the subject treated in this study. Specifically, a sensitivity analysis based on a large data stack of interferometric pairs in order to quantitatively estimate at a pixel level the time beyond which each interferometric phase becomes practically unusable is presented. The estimation and mapping of the spatial distribution of the temporal decorrelation times in an area without a necessary a priori knowledge of its surface characteristics is a

  15. Development and Evaluation of Science and Technology Education Program Using Interferometric SAR

    NASA Astrophysics Data System (ADS)

    Ito, Y.; Ikemitsu, H.; Nango, K.

    2016-06-01

    This paper proposes a science and technology education program to teach junior high school students to measure terrain changes by using interferometric synthetic aperture radar (SAR). The objectives of the proposed program are to evaluate and use information technology by performing SAR data processing in order to measure ground deformation, and to incorporate an understanding of Earth sciences by analyzing interferometric SAR processing results. To draft the teaching guidance plan for the developed education program, this study considers both science and technology education. The education program was used in a Japanese junior high school. An educational SAR processor developed by the authors and the customized Delft object-oriented radar interferometric software package were employed. Earthquakes as diastrophism events were chosen as practical teaching materials. The selected events indicate clear ground deformation in differential interferograms with high coherence levels. The learners were able to investigate the ground deformations and disasters caused by the events. They interactively used computers and became skilled at recognizing the knowledge and techniques of information technology, and then they evaluated the technology. Based on the results of pre- and post-questionnaire surveys and self-evaluation by the learners, it was clarified that the proposed program was applicable for junior high school education, and the learners recognized the usefulness of Earth observation technology by using interferometric SAR. The usefulness of the teaching materials in the learning activities was also shown through the practical teaching experience.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  17. First Results from an Airborne Ka-Band SAR Using SweepSAR and Digital Beamforming

    NASA Technical Reports Server (NTRS)

    Sadowy, Gregory A.; Ghaemi, Hirad; Hensley, Scott C.

    2012-01-01

    SweepSAR is a wide-swath synthetic aperture radar technique that is being studied for application on the future Earth science radar missions. This paper describes the design of an airborne radar demonstration that simulates an 11-m L-band (1.2-1.3 GHz) reflector geometry at Ka-band (35.6 GHz) using a 40-cm reflector. The Ka-band SweepSAR Demonstration system was flown on the NASA DC-8 airborne laboratory and used to study engineering performance trades and array calibration for SweepSAR configurations. We present an instrument and experiment overview, instrument calibration and first results.

  18. An Automated Mapping Processor using C-Band Interferometric SAR Data

    NASA Technical Reports Server (NTRS)

    Rodriguez, E.; Michel, T. R.; Martin, J. M.; Houshmand, B.

    1996-01-01

    We describe a processor which has been implemented to generate map products starting from C-band interferometric data. The first stage of the processor consists of the conventional interferometric synthetic aperture radar (SAR) processing producing a digital elevation model (DEM) and a SAR brightness image in sensor coordinates. In the second stage of processing, a land use classification map is obtained by using the DEM, brightness, and interferometric correlation layers. Auxiliary layers which include a drainage layer, a height gradient layer, a height error layer, an estimated penetration layer, and a shaded relief layer are also computed. In the final step, all UTM collocated layers are combined in a geographical information system (GIS) which allows for both hard copy map products and digital applications.

  19. An Automated Mapping Processor Using C-Band Interferometric SAR Data

    NASA Technical Reports Server (NTRS)

    Rodriguez, E.; Michel, T. R.; Martin, J. M.; Houshmand, B.

    1996-01-01

    We present the description of a processor which has been implemented to generate map products starting from C-band interferometric data. The first stage of the processor consists of the conventional interferometric SAR processing producing a Digital Elevation Model (DEMs) and a SAR brightness image in sensor coordinates. In the second stage of processing, a land use classification map is obtained by using the DEM, brightness, and interferometric correlation layers. Auxiliary layers which include a drainage layer, a height gradient layer, a height error layer, an estimated penetration layer, and a shaded relief layer are also computed. In the final step, all UTM collocated layers are combined in a GIS system which allows for both hard copy map products and for digital applications.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  1. Cross-calibration between airborne SAR sensors

    NASA Technical Reports Server (NTRS)

    Zink, Manfred; Olivier, Philippe; Freeman, Anthony

    1993-01-01

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

  2. Interferometric SAR phase difference calibration: Methods and results

    SciTech Connect

    Bickel, D.L.; Hensley, W.H.

    1993-12-31

    This paper addresses the steps necessary to determine and maintain the phase calibration of a two-channel interferometric synthetic aperture radar (IFSAR). The method, setup, and accuracy of four different calibration techniques are compared. The most novel technique involves pointing the interferometric baseline at nadir and imaging a lake surface. The other techniques include measuring various flat surfaces in traditional side-looking IFSAR maps, in-flight closed-loop calibration path measurements, and static laboratory measurements. Initial results indicate that, using combinations of these measurements, it is possible to maintain the interferometric phase calibration of Sandia National Laboratories` K{sub U} Band IFSAR to better than 3 degrees. The time variability of various parts of the calibration and requirements for recalibration are also discussed.

  3. First Results from an Airborne Ka-band SAR Using SweepSAR and Digital Beamforming

    NASA Technical Reports Server (NTRS)

    Sadowy, Gregory; Ghaemi, Hirad; Hensley, Scott

    2012-01-01

    NASA/JPL has developed SweepSAR technique that breaks typical Synthetic Aperture Radar (SAR) trade space using time-dependent multi-beam DBF on receive. Developing SweepSAR implementation using array-fed reflector for proposed DESDynI Earth Radar Mission concept. Performed first-of-a-kind airborne demonstration of the SweepSAR concept at Ka-band (35.6 GHz). Validated calibration and antenna pattern data sufficient for beam forming in elevation. (1) Provides validation evidence that the proposed Deformation Ecosystem Structure Dynamics of Ice (DESDynI) SAR architecture is sound. (2) Functions well even with large variations in receiver gain / phase. Future plans include using prototype DESDynI SAR digital flight hardware to do the beam forming in real-time onboard the aircraft.

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  5. Using dynamic interferometric synthetic aperature radar (InSAR) to image fast-moving surface waves

    DOEpatents

    Vincent, Paul

    2005-06-28

    A new differential technique and system for imaging dynamic (fast moving) surface waves using Dynamic Interferometric Synthetic Aperture Radar (InSAR) is introduced. This differential technique and system can sample the fast-moving surface displacement waves from a plurality of moving platform positions in either a repeat-pass single-antenna or a single-pass mode having a single-antenna dual-phase receiver or having dual physically separate antennas, and reconstruct a plurality of phase differentials from a plurality of platform positions to produce a series of desired interferometric images of the fast moving waves.

  6. Interferometric synthetic aperture radar (InSAR)—its past, present and future

    USGS Publications Warehouse

    Lu, Zhong; Kwoun, Oh-Ig; Rykhus, R.P.

    2007-01-01

    Very simply, interferometric synthetic aperture radar (InSAR) involves the use of two or more synthetic aperture radar (SAR) images of the same area to extract landscape topography and its deformation patterns. A SAR system transmits electromagnetic waves at a wavelength that can range from a few millimeters to tens of centimeters and therefore can operate during day and night under all-weather conditions. Using SAR processing technique (Curlander and McDonough, 1991), both the intensity and phase of the reflected (or backscattered) radar signal of each ground resolution element (a few meters to tens of meters) can be calculated in the form of a complex-valued SAR image that represents the reflectivity of the ground surface. The amplitude or intensity of the SAR image is determined primarily by terrain slope, surface roughness, and dielectric constants, whereas the phase of the SAR image is determined primarily by the distance between the satellite antenna and the ground targets. InSAR imaging utilizes the interaction of electromagnetic waves, referred to as interference, to measure precise distances between the satellite antenna and ground resolution elements to derive landscape topography and its subtle change in elevation.

  7. Tropical Forest Vegetation Profiles and Biomass from Multibaseline Interferometric SAR at C- band

    NASA Astrophysics Data System (ADS)

    Treuhaft, R.; Chapman, B.; Santos, J. R.; Dutra, L.; Goncalves, F.; Graca, P. A.; Drake, J.

    2007-12-01

    Interferometric synthetic aperture radar (InSAR) involves the reception of SAR signals at two spatially separated ends of a baseline. The resulting phase and coherence observations from InSAR are both sensitive to the vertical structure of vegetation. However, multiple InSAR observations--more than one phase-coherence-pair--are needed to estimate parameters describing vertical structure. Multiple observations can be made with different baselines, polarizations, or frequencies. This talk reviews why InSAR is sensitive to vertical structure. It then describes an experiment in the tropical forests of La Selva Biological Station in Costa Rica in which 12-14 baselines were used to estimate vegetation vertical profiles at C-band. Calibration of the InSAR phases and coherences with nearby pastures was essential for interpreting the data for vegetation, rather than surface, characteristics. Relative density profiles from primary, secondary, and selectively logged forests will be shown along with profiles from abandoned pastures. Field methods used to validate the profiles involve measuring individual tree dimensions, and the production of field profiles will be described and compared to InSAR profiles. Lidar profiles will also be shown for comparison. Functions of the InSAR profiles will be used estimate biomass of 30 stands

  8. Spotlight SAR interferometry for terrain elevation mapping and interferometric change detection

    SciTech Connect

    Eichel, P.H.; Ghiglia, D.C.; Jakowatz, C.V. Jr.

    1996-02-01

    In this report, we employ an approach quite different from any previous work; we show that a new methodology leads to a simpler and clearer understanding of the fundamental principles of SAR interferometry. This methodology also allows implementation of an important collection mode that has not been demonstrated to date. Specifically, we introduce the following six new concepts for the processing of interferometric SAR (INSAR) data: (1) processing using spotlight mode SAR imaging (allowing ultra-high resolution), as opposed to conventional strip-mapping techniques; (2) derivation of the collection geometry constraints required to avoid decorrelation effects in two-pass INSAR; (3) derivation of maximum likelihood estimators for phase difference and the change parameter employed in interferometric change detection (ICD); (4) processing for the two-pass case wherein the platform ground tracks make a large crossing angle; (5) a robust least-squares method for two-dimensional phase unwrapping formulated as a solution to Poisson`s equation, instead of using traditional path-following techniques; and (6) the existence of a simple linear scale factor that relates phase differences between two SAR images to terrain height. We show both theoretical analysis, as well as numerous examples that employ real SAR collections to demonstrate the innovations listed above.

  9. The effect of scattering from buildings on interferometric SAR measurements

    SciTech Connect

    Bickel, D.L.; Hensley, W.H.; Yocky, D.A.

    1997-06-01

    The determination of elevation models of buildings using interferometric synthetic aperture radar (IFSAR) is an important area of active research. The focus of this paper is on some of the unique scattering mechanisms that occur with buildings and how they affect the IFSAR height measurement and the coherence. The authors will show by theory and examples that the various data products obtained from IFSAR can be used to aid in interpreting building height results. They will also present a method that they have used successfully in mapping buildings in Washington D.C.

  10. Estimating tropical-forest density profiles from multibaseline interferometric SAR

    NASA Technical Reports Server (NTRS)

    Treuhaft, Robert; Chapman, Bruce; dos Santos, Joao Roberto; Dutra, Luciano; Goncalves, Fabio; da Costa Freitas, Corina; Mura, Jose Claudio; de Alencastro Graca, Paulo Mauricio

    2006-01-01

    Vertical profiles of forest density are potentially robust indicators of forest biomass, fire susceptibility and ecosystem function. Tropical forests, which are among the most dense and complicated targets for remote sensing, contain about 45% of the world's biomass. Remote sensing of tropical forest structure is therefore an important component to global biomass and carbon monitoring. This paper shows preliminary results of a multibasline interfereomtric SAR (InSAR) experiment over primary, secondary, and selectively logged forests at La Selva Biological Station in Costa Rica. The profile shown results from inverse Fourier transforming 8 of the 18 baselines acquired. A profile is shown compared to lidar and field measurements. Results are highly preliminary and for qualitative assessment only. Parameter estimation will eventually replace Fourier inversion as the means to producing profiles.

  11. Techniques and Tools for Estimating Ionospheric Effects in Interferometric and Polarimetric SAR Data

    NASA Technical Reports Server (NTRS)

    Rosen, P.; Lavalle, M.; Pi, X.; Buckley, S.; Szeliga, W.; Zebker, H.; Gurrola, E.

    2011-01-01

    The InSAR Scientific Computing Environment (ISCE) is a flexible, extensible software tool designed for the end-to-end processing and analysis of synthetic aperture radar data. ISCE inherits the core of the ROI_PAC interferometric tool, but contains improvements at all levels of the radar processing chain, including a modular and extensible architecture, new focusing approach, better geocoding of the data, handling of multi-polarization data, radiometric calibration, and estimation and correction of ionospheric effects. In this paper we describe the characteristics of ISCE with emphasis on the ionospheric modules. To detect ionospheric anomalies, ISCE implements the Faraday rotation method using quadpolarimetric images, and the split-spectrum technique using interferometric single-, dual- and quad-polarimetric images. The ability to generate co-registered time series of quad-polarimetric images makes ISCE also an ideal tool to be used for polarimetric-interferometric radar applications.

  12. Onboard Interferometric SAR Processor for the Ka-Band Radar Interferometer (KaRIn)

    NASA Technical Reports Server (NTRS)

    Esteban-Fernandez, Daniel; Rodriquez, Ernesto; Peral, Eva; Clark, Duane I.; Wu, Xiaoqing

    2011-01-01

    An interferometric synthetic aperture radar (SAR) onboard processor concept and algorithm has been developed for the Ka-band radar interferometer (KaRIn) instrument on the Surface and Ocean Topography (SWOT) mission. This is a mission- critical subsystem that will perform interferometric SAR processing and multi-look averaging over the oceans to decrease the data rate by three orders of magnitude, and therefore enable the downlink of the radar data to the ground. The onboard processor performs demodulation, range compression, coregistration, and re-sampling, and forms nine azimuth squinted beams. For each of them, an interferogram is generated, including common-band spectral filtering to improve correlation, followed by averaging to the final 1 1-km ground resolution pixel. The onboard processor has been prototyped on a custom FPGA-based cPCI board, which will be part of the radar s digital subsystem. The level of complexity of this technology, dictated by the implementation of interferometric SAR processing at high resolution, the extremely tight level of accuracy required, and its implementation on FPGAs are unprecedented at the time of this reporting for an onboard processor for flight applications.

  13. Motion compensation for aircraft-borne interferometric SAR

    NASA Astrophysics Data System (ADS)

    Bullock, Richard John

    This research has studied data driven techniques for roll compensation for aircraft-borne InSAR, for platforms where an accurate Inertial Navigation Unit (INU) is inappropriate due to limitations on weight or cost, such as a low-cost civilian mapping system or a miniature UAV. It is shown that for unknown topography, roll errors cannot simply be filtered from the interferogram due to a fundamental ambiguity between aircraft roll effects and certain types of undulating terrain. The solution to this problem lies in the differential Doppler shifts of the signals received at the two antennas. These are proportional to the aircraft roll rate and can be extracted by incoherent or coherent means and utilised to reconstruct the aircraft roll history. This research analyses, experimentally evaluates and further develops the incoherent Differential Doppler (DD) method for roll compensation, developed to the proof-of-concept stage by A. Currie at QinetiQ (Malvern) and compares this with the two-look method, which is a novel coherent technique developed, analysed and experimentally evaluated as part of this PhD from an original idea proposed by Prof. R. Voles of UCL. By means of empirical analysis, numerical simulation and real test data from the QinetiQ C-Band InSAR, it is shown that the two-look method offers significant advantages in sensitivity, frequency performance, robustness and efficiency of implementation over the DD method, particularly at long range. The experimental results also show that for the QinetiQ C-Band InSAR, the two-look method provides roll compensation to a similar quality or better than provided by the on-board Litton-93 INU, which has a specified accuracy of +/-0.05°. Ambiguities in the roll rate estimates from other motions are also shown to be small for this platform, and could be reduced further by employing differential GPS track compensation.

  14. A null-steering viewpoint of interferometric SAR

    SciTech Connect

    BICKEL,DOUGLAS L.

    2000-05-02

    Interferometric synthetic aperture radar (IFSAR) extends the two-dimensional imaging capability of traditional synthetic aperture radar to three-dimensions by using an aperture in the elevation plane to estimate the 3-D structure of the target. The operation of this additional aperture can be viewed from a null-steering point of view, rather than the traditional phase determination point of view. Knowing that IFSAR can be viewed from the null-steering perspective allows one to take advantage of the mathematical foundation developed for null-steering arrays. In addition, in some problems of interest in IFSAR the null-steering perspective provides better intuition and suggests alternative solutions. One example is the problem of estimating building height where layover is present.

  15. Modified patch-based locally optimal Wiener method for interferometric SAR phase filtering

    NASA Astrophysics Data System (ADS)

    Wang, Yang; Huang, Haifeng; Dong, Zhen; Wu, Manqing

    2016-04-01

    This paper presents a modified patch-based locally optimal Wiener (PLOW) method for interferometric synthetic aperture radar (InSAR) phase filtering. PLOW is a linear minimum mean squared error (LMMSE) estimator based on a Gaussian additive noise condition. It jointly estimates moments, including mean and covariance, using a non-local technique. By using similarities between image patches, this method can effectively filter noise while preserving details. When applied to InSAR phase filtering, three modifications are proposed based on spatial variant noise. First, pixels are adaptively clustered according to their coherence magnitudes. Second, rather than a global estimator, a locally adaptive estimator is used to estimate noise covariance. Third, using the coherence magnitudes as weights, the mean of each cluster is estimated, using a weighted mean to further reduce noise. The performance of the proposed method is experimentally verified using simulated and real data. The results of our study demonstrate that the proposed method is on par or better than the non-local interferometric SAR (NL-InSAR) method.

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  17. Estimating snow water equivalent (SWE) using interferometric synthetic aperture radar (InSAR)

    NASA Astrophysics Data System (ADS)

    Deeb, Elias J.

    Since the early 1990s, radar interferometry and interferometric synthetic aperture radar (InSAR) have been used extensively to measure changes in the Earth's surface. Previous research has presented theory for estimating snow properties, including potential for snow water equivalent (SWE) retrieval, using InSAR. The motivation behind using remote sensing to estimate SWE is to provide a more complete, continuous set of "observations" to assist in water management operations, climate change studies, and flood hazard forecasting. The research presented here primarily investigates the feasibility of using the InSAR technique at two different wavelengths (C-Band and L-Band) for SWE retrieval of dry snow within the Kuparuk watershed, North Slope, Alaska. Estimating snow distribution around meteorological towers on the coastal plain using a three-day repeat orbit of C-Band InSAR data was successful (Chapter 2). A longer wavelength L-band SAR is evaluated for SWE retrievals (Chapter 3) showing the ability to resolve larger snow accumulation events over a longer period of time. Comparisons of InSAR estimates and late spring manual sampling of SWE show a R2 = 0.61 when a coherence threshold is used to eliminate noisy SAR data. Qualitative comparisons with a high resolution digital elevation model (DEM) highlight areas of scour on windward slopes and areas of deposition on leeward slopes. When compared to a mid-winter transect of manually sampled snow depths, the InSAR SWE estimates yield a RMSE of 2.21cm when a bulk snow density is used and corrections for bracketing the satellite acquisition timing is performed. In an effort to validate the interaction of radar waves with a snowpack, the importance of the "dry snow" assumption for the estimation of SWE using InSAR is tested with an experiment in Little Cottonwood Canyon, Alta, Utah (Chapter 5). Snow wetness is shown to have a significant effect on the velocity of propagation within the snowpack. Despite the radar

  18. Interferometric SAR observations of the Pine Island Glacier catchment area

    NASA Astrophysics Data System (ADS)

    Stenoien, Mark Daniel

    The catchment area of Pine Island Glacier, in West Antarctica, is mapped using satellite-radar interferometry and satellite-radar altimetery. The synthetic-aperture radar signal-processing algorithm implemented for this task uses precise (post-processed) orbit-ephemerides and a radar-altimeter digital-elevation-model to generate terrain-corrected and geolocated complex-imagery. The interferometric signal-processing algorithm implemented uses the same precise orbit-ephemerides and digital-elevation-model, together with synthetic-aperture-radar data collected from ascending- and descending-orbit passes to generate geometrically-corrected maps of true ice-surface motion. Satellite radar-altimeter data are used to create a digital elevation-model of the Pine Island Glacier catchment area via a unique algorithm that slope-corrects and grids the topographic estimates in a single step. The application of these tools reveals a system of tributaries channeling ice from the basin-like catchment area into the fast-flowing outlet glacier. None of the 7 tributaries mapped show a clear "onset" region, where sliding begins suddenly to dominate internal deformation as the predominant mode of ice motion; rather there is a gradual increase in ice speed, along with a gradual decrease in driving stress, along the axis of each tributary. Overall, however, regions of high (low) driving stress are closely associated with regions of large (small) surface slope, but show little correlation with the configuration of the tributaries. Furthermore, an estimate of the mass-balance of the observed portions of the Pine Island Glacier catchment area suggests that the northern and eastern slopes of the catchment area are gaining mass, while the southern slope is losing mass, making the net-balance for the observed area not distinguishable from zero.

  19. P-3 SAR motion compensation techniques

    NASA Astrophysics Data System (ADS)

    Schwartz, Debra S.; Mansfield, Arthur W.; Roth, Duane; Rais, Houra

    2000-08-01

    The potential of airborne SAR to support the search and rescue mission needs to be investigated. Interferometric SAR (IFSAR) is to process P-3 airborne SAR data to evaluate products such as Coherent Change Detection (CCD) and Digital Elevation Models (DEM). The most crucial step in this process is the precise registration of the two SAR images obtained from separate passes. This paper presents a new technique for this registration step.

  20. Interferometric SAR monitoring of the Vallcebre landslide (Spain) using corner reflectors

    NASA Astrophysics Data System (ADS)

    Crosetto, M.; Gili, J. A.; Monserrat, O.; Cuevas-González, M.; Corominas, J.; Serral, D.

    2013-04-01

    This paper describes the deformation monitoring of the Vallcebre landslide (Eastern Pyrenees, Spain) using the Differential Interferometric Synthetic Aperture Radar (DInSAR) technique and corner reflectors (CRs). The fundamental aspects of this satellite-based deformation monitoring technique are described to provide the key elements needed to fully understand and correctly interpret its results. Several technical and logistic aspects related to the use of CRs are addressed including an analysis of the suitability of DInSAR data to monitor a specific landslide, a discussion on the choice of the type of CRs, suggestions for the installation of CRs and a description of the design of a CR network. This is followed by the description of the DInSAR data analysis procedure required to derive deformation estimates starting from the main observables of the procedure, i.e., the interferometric phases. The main observation equation is analysed, discussing the role of each phase component. A detailed discussion is devoted to the phase unwrapping problem, which has a direct impact on the deformation monitoring capability. Finally, the performance of CRs for monitoring ground displacements has been tested in the Vallcebre landslide (Eastern Pyrenees, Spain). Two different periods, which provide interesting results to monitor over time the kinematics of different parts of the considered landslide unit, are analysed and described.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    SciTech Connect

    Raynal, Ann Marie; Doerry, Armin Walter

    2013-02-01

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

  3. GeoEarthScope Airborne LiDAR and Satellite InSAR Imagery

    NASA Astrophysics Data System (ADS)

    Phillips, D. A.; Jackson, M. E.; Meertens, C.

    2008-12-01

    UNAVCO has successfully acquired a significant volume of aerial and satellite geodetic imagery as part of GeoEarthScope, a component of the EarthScope Facility project funded by the National Science Foundation. All GeoEarthScope acquisition activities are now complete. Airborne LiDAR data acquisitions took place in 2007 and 2008 and cover a total area of more than 5000 square kilometers. The primary LiDAR survey regions cover features in Northern California, Southern/Eastern California, the Pacific Northwest, the Intermountain Seismic Belt (including the Wasatch and Teton faults and Yellowstone), and Alaska. We have ordered and archived more than 28,000 scenes (more than 81,000 frames) of synthetic aperture radar (SAR) data suitable for interferometric analyses covering most of the western U.S. and parts of Alaska and Hawaii from several satellite platforms, including ERS-1/2, ENVISAT and RADARSAT. In addition to ordering data from existing archives, we also tasked the ESA ENVISAT satellite to acquire new SAR data in 2007 and 2008. GeoEarthScope activities were led by UNAVCO, guided by the community and conducted in partnership with the USGS and NASA. Processed imagery products, in addition to formats intended for use in standard research software, can also be viewed using general purpose tools such as Google Earth. We present a summary of these vast geodetic imagery datasets, totaling tens of terabytes, which are freely available to the community.

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  5. Monitoring delta subsidence with Interferometric Synthetic Aperture Radar (InSAR)

    NASA Astrophysics Data System (ADS)

    Higgins, S.; Overeem, I.; Syvitski, J. P.

    2014-12-01

    Can subsidence in river deltas be monitored in near real-time at the spatial and temporal resolution needed for informing critical management decisions? Interferometric Synthetic Radar Aperture (InSAR) is a satellite-based technique that can map ground deformation with millimeter-scale vertical resolution over thousands of square kilometers. InSAR has enormous potential to shed light on the dynamics of actively subsiding deltas, but the technique is not commonly applied outside of major cities due to the difficulty of performing InSAR in wet, vegetated settings. Given these limitations, how can InSAR best serve the global effort to monitor sinking deltas? Here, an overview of InSAR processing is provided that addresses delta-specific challenges, including frequent cloud-cover in tropical areas; noisy signals in wetlands and flooded fields; dense forests that interact unpredictably with different radar wavelengths; flat landscapes that hinder image stacking algorithms; rapid urban development that can render Digital Elevation Models (DEMs) inaccurate; and a lack of in situ GPS (Global Positioning System) receivers for InSAR calibration. InSAR has unique value for monitoring subsidence in deltas, and some natural and anthropogenic drivers of subsidence can be resolved by InSAR. High-resolution InSAR measurements from the Ganges-Brahmaputra Delta (GBD) are then presented and validated against GPS data. Surface motion is shown to reflect subsurface stratigraphy, and sediment compaction is shown to be the most important factor in this delta on short (non-tectonic) timescales. Average compaction rates throughout the eastern delta range from 0 to > 18 mm/y, varying by more than an order of magnitude depending on the ages and grain sizes of surface and subsurface sediment layers. Fastest subsidence is observed in Holocene organic-rich mud, and slowest subsidence is observed along the Meghna River and in areas with surface or subsurface sand deposits. Although groundwater

  6. Detection of damaged urban areas using interferometric SAR coherence change with PALSAR-2

    NASA Astrophysics Data System (ADS)

    Watanabe, Manabu; Thapa, Rajesh Bahadur; Ohsumi, Tsuneo; Fujiwara, Hiroyuki; Yonezawa, Chinatsu; Tomii, Naoya; Suzuki, Sinichi

    2016-07-01

    The interferometric SAR coherence-change technique with coherence filter and polarization (HH and HV) has been used to detect the parts of buildings damaged by the 2015 Gorkha Earthquake. A survey of the building damage was conducted in every house to evaluate the detection accuracy in the Khokana and Sankhu urban areas in the Kathmandu Valley of Nepal. The damaged parts of the urban area were adequately detected using coherence-change (∆ γ) values obtained before the earthquake ( γ pre) and during the inter-seismic stage of the earthquake ( γ int). The use of a coherence filter effectively increased overall accuracy by ~2.1 to 7.0 % with HH polarization. The incorporation of HV polarization marginally increased the accuracy (~0.9 to 1.2 %). It was confirmed that road damage due to liquefaction was also observed using the interferometric SAR coherence-change detection technique. The classification accuracy was lower (27.1-35.1 %) for areas that were damaged. However, higher accuracy (97.8-99.2 %) was achieved for areas that were damage-free, in ∆ γ obtained from HH and HV polarization with a coherence filter. This helped to identify the damaged urban areas (using this technique) immediately after occurrence of an earthquake event.

  7. Mapping slope movements in Alpine environments using TerraSAR-X interferometric methods

    NASA Astrophysics Data System (ADS)

    Barboux, Chloé; Strozzi, Tazio; Delaloye, Reynald; Wegmüller, Urs; Collet, Claude

    2015-11-01

    Mapping slope movements in Alpine environments is an increasingly important task in the context of climate change and natural hazard management. We propose the detection, mapping and inventorying of slope movements using different interferometric methods based on TerraSAR-X satellite images. Differential SAR interferograms (DInSAR), Persistent Scatterer Interferometry (PSI), Short-Baseline Interferometry (SBAS) and a semi-automated texture image analysis are presented and compared in order to determine their contribution for the automatic detection and mapping of slope movements of various velocity rates encountered in Alpine environments. Investigations are conducted in a study region of about 6 km × 6 km located in the Western Swiss Alps using a unique large data set of 140 DInSAR scenes computed from 51 summer TerraSAR-X (TSX) acquisitions from 2008 to 2012. We found that PSI is able to precisely detect only points moving with velocities below 3.5 cm/yr in the LOS, with a root mean squared error of about 0.58 cm/yr compared to DGPS records. SBAS employed with 11 days summer interferograms increases the range of detectable movements to rates up to 35 cm/yr in the LOS with a root mean squared error of 6.36 cm/yr, but inaccurate measurements due to phase unwrapping are already possible for velocity rates larger than 20 cm/year. With the semi-automated texture image analysis the rough estimation of the velocity rates over an outlined moving zone is accurate for rates of "cm/day", "dm/month" and "cm/month", but due to the decorrelation of yearly TSX interferograms this method fails for the observation of slow movements in the "cm/yr" range.

  8. River Delta Subsidence Measured with Interferometric Synthetic Aperture Radar (InSAR)

    NASA Astrophysics Data System (ADS)

    Higgins, Stephanie

    This thesis addresses the need for high-resolution subsidence maps of major world river deltas. Driven by a combination of rising water, sediment compaction, and reduced sediment supply due to damming and flood control, many deltas are sinking relative to sea level. A lack of data constraining rates and patterns of subsidence has made it difficult to determine the relative contributions of each factor in any given delta, however, or to assess whether the primary drivers of land subsidence are natural or anthropogenic. In recent years, Interferometric Synthetic Aperture Radar (InSAR) has emerged as a satellite-based technique that can map ground deformation with mm-scale accuracy over thousands of square kilometers. These maps could provide critical insight into the drivers of subsidence in deltas, but InSAR is not typically applied to non-urban delta areas due to the difficulties of performing the technique in wet, vegetated settings. This thesis addresses those difficulties and achieves high-resolution measurements of ground deformation in rural deltaic areas. Chapter 1 introduces the processes that drive relative sea level rise in river deltas and investigates open questions in delta subsidence research. Chapter 2 assesses the performance of InSAR in delta settings and reviews interferogram generation in the context of delta analysis, presenting delta-specific processing details and guiding interpretation in these challenging areas. Chapter 3 applies Differential (D-) InSAR to the coast of the Yellow River Delta in China. Results show that subsidence rates are as high as 250 mm/y due to groundwater extraction at aquaculture facilities, a rate that exceeds local and global average sea level rise by nearly two orders of magnitude and suggests a significant hazard for Asian megadeltas. Chapter 4 applies interferometric stacking and Small Baseline Subset (SBAS)-InSAR to the Ganges-Brahmaputra Delta, Bangladesh. Results show that stratigraphy controls subsidence in

  9. Structural Biomass Estimation from L-band Interferometric SAR and Lidar

    NASA Astrophysics Data System (ADS)

    Treuhaft, R. N.; Chapman, B. D.; Goncalves, F.; Hensley, S.; dos Santos, J. R.; Graca, P. A.; Dutra, L.

    2011-12-01

    After a review of biomass estimation from interferometric SAR (InSAR) at all bands over the last 15 years, and a brief review of lidar biomass estimation, this paper discusses structure and biomass estimation from simultaneously acquired (not repeat-track) InSAR at L-band. We will briefly discuss the history of regression of biomass to InSAR raw observations (coherence and phase) and structural parameters (height, standard deviation, Fourier component). Lidar biomass estimation from functions of the waveform will be discussed. We review our structural and biomass estimation results for C-band InSAR at vertical polarization for 12-14 baselines in La Selva Biological Station, Costa Rica. C-band vertical scales were between 12 and 100 m for structure estimation, but only between 50 and 100 m for biomass estimation, due to phase calibration problems at the shorter vertical wavelengths (larger baselines). Most of the talk will be spent on L-band, simultaneously acquired multibaseline InSAR, also at La Selva, acquired at vertical polarization. Because the vertical interferometric scale is proportional to the radar altitude times the wavelength over the baseline length, the AirSAR aircraft had to be flown very low (1.2 km) to realize vertical scales at L-band of 60 m and higher. Our lidar biomass estimation suggests that vertical scales of 14 m-100 m are optimal for biomass estimation. We will try three different approaches to biomass estimation with the limited high vertical scales we have available: 1) We will regress biomass to Fourier transforms as in the C-band and lidar study, but with 60 m - 100+ m vertical scales we do not expect accuracies to be as high as for the lidar demonstration (58 Mg/ha RMS scatter of estimated about field biomass for biomasses up to 450 Mg/ha), which used Fourier vertical wavelengths of 15 m-20 m. In addition to using Fourier components, 2) we will report the use of the derivative of the InSAR complex coherence with respect to Fourier

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  11. Interferometric processing of C-band SAR data for the improvement of stand age estimation in rubber plantation

    NASA Astrophysics Data System (ADS)

    Trisasongko, Bambang H.; Paull, David J.; Panuju, Dyah R.

    2015-01-01

    Rubber ranks the second largest plantation in Indonesia after oil palm. While oil palm plantations have been exploited mainly by large companies, many rubber plantations are still managed by peasant farmers who maintain its biodiversity. Due to its broad and scattered location, monitoring tropical rubber plantation is a crucial application of active remote sensing. In this paper, the backscatter coefficient of Envisat Advanced Synthetic Aperture Radar (ASAR) is compared to interferometric coherence to study the relationship between stand age and SAR parameters. It is shown that VV polarized C-band SAR achieves its saturation level in plantations aged about 5-10 years. Extension of saturation level can be achieved by processing an interferometric pair of ASAR data, which results in interferometric coherence. In this paper, coherence can take up to 20 years stand age to achieve prior to saturation. Since stand age is highly related to biomass, this finding argues that the biomass can be best estimated using coherence.

  12. Integrated Analysis of Interferometric SAR, Satellite Altimetry and Hydraulic Modeling to Quantify Louisiana Wetland Dynamics

    NASA Technical Reports Server (NTRS)

    Lee, Hyongki; Kim, Jin-woo; Lu, Zhong; Jung, Hahn Chul; Shum, C. K.; Alsdorf, Doug

    2012-01-01

    Wetland loss in Louisiana has been accelerating due primarily to anthropogenic and nature processes, and is being advocated as a problem with national importance. Accurate measurement or modeling of wetland-wide water level changes, its varying extent, its storage and discharge changes resulting in part from sediment loads, erosion and subsidence are fundamental to assessment of hurricane-induced flood hazards and wetland ecology. Here, we use innovative method to integrate interferometric SAR (InSAR) and satellite radar altimetry for measuring absolute or geocentric water level changes and applied the methodology to remote areas of swamp forest in coastal Louisiana. Coherence analysis of InSAR pairs suggested that the HH polarization is preferred for this type of observation, and polarimetric analysis can help to identi:fy double-bonnce backscattering areas in the wetland. Envisat radar altimeter-measured 18- Hz (along-track sampling of 417 m) water level data processed with regional stackfile method have been used to provide vertical references for water bodies separated by levees. The high-resolution (approx.40 m) relative water changes measured from ALOS PALSAR L-band and Radarsat-l C-band InSAR are then integrated with Envisat radar altimetry to obtain absolute water level. The resulting water level time series were validated with in situ gauge observations within the swamp forest. Furthermore, we compare our water elevation changes with 2D flood modeling from LISFLOOD hydrodynamic model. Our study demonstrates that this new technique allows retrospective reconstruction and concurrent monitoring of water conditions and flow dynamics in wetlands, especially those lacking gauge networks.

  13. Yellowstone Volcanic Unrest from GPS and SAR Interferometric Observations between 1992 and 2015

    NASA Astrophysics Data System (ADS)

    Aly, M. H.

    2015-12-01

    Incorporating geodetic measurements from nine Global Positioning System (GPS) stations and multi-sensor Interferometric Synthetic Aperture Radar (InSAR), six prominent episodes of Yellowstone caldera unrest are identified between 1992 and 2015. Episode 1: 1992-1995, deflation rate of about 2.7 cm/yr, episode 2: 1996-2000, minimal deflation of 0.5 cm/yr with considerable inflation of 1.7 cm/yr at Norris, episode 3: 2000-2004, slight deflation of 0.7 cm/yr with local inflation of 0.6 cm/yr at Norris, episode 4: 2004-2009, extraordinary inflation of 3-8 cm/yr with substantial deflation of 1-4 cm/yr at Norris, episode 5: 2010-2014, notable deflation of about 1-2.4 cm/yr across the entire caldera floor, and ultimately episode 6: 2014-2015, remarkable caldera-wide inflation of about 2-6 cm/yr. During the period of observation (1992-2015), extensive deformation has occurred primarily at three locations; namely, the Mallard Lake resurgent dome, the Sour Creek resurgent dome, and the Norris Geyser Basin that is located nearby the northwestern rim of the caldera. InSAR data acquired during 1992-2015 by ERS-1, ERS-2, ENVISAT, TerraSAR-X, TanDEM-X, and Sentinel-1 are analyzed using the two-pass and the small baseline subset interferometric methods. The created interferograms do not show any alignment of crustal deformation with fault zones across the intermittently active caldera, which indicate that the magma charge and discharge, as well as the widespread hydrothermal activity are responsible for the induced deformation. Fault zones most likely have acted as pathways for the movements of magma and hydrothermal fluids, but they do not have any influence on the measured rates of surface motion. Source modeling of recent GPS and InSAR measurements indicates the existence of two distinct planar sources beneath the caldera (8-12 km) and the Norris Geyser Basin (10-16 km).

  14. Image quality specification and maintenance for airborne SAR

    NASA Astrophysics Data System (ADS)

    Clinard, Mark S.

    2004-08-01

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

  15. Urban area structuring mapping using an airborne polarimetric SAR image

    NASA Astrophysics Data System (ADS)

    Simonetto, Elisabeth; Malak, Charbel

    2009-09-01

    For several years, image classification and pattern recognition algorithms have been developed for the land coverage mapping using radar and multispectral imagery with medium to large pixel size. As several satellites now distribute submetric-pixel and metric-pixel images (for example QUICKBIRD,TERRASAR-X), the research turns to the study of the structure of cities: building structuring, grassy areas, road networks, etc, and the physical description of the urban surfaces. In that context, we propose to underline new potentialities of submetric-pixel polarimetric SAR images. We deal with the characterization of roofs and the mapping of trees. For that purpose, a first analysis based on photo-interpretation and the assessement of several polarimetric descriptors is carried out. Then, an image classification scheme is built using the polarimetric H/alpha-Wishart algorithm, followed by a decision tree. This one is based on the most pertinent polarimetric descriptors and aims at reducing the classification errors. The result proves the potential of such data. Our work relies on an image of a suburban area, acquired by the airborne RAMSES SAR sensor of ONERA.

  16. Advanced Interferometric Synthetic Aperture Imaging Radar (InSAR) for Dune Mapping

    NASA Astrophysics Data System (ADS)

    Havivi, Shiran; Amir, Doron; Schvartzman, Ilan; August, Yitzhak; Mamman, Shimrit; Rotman, Stanely R.; Blumberg, Dan G.

    2016-04-01

    Aeolian morphologies are formed in the presence of sufficient wind energy and available lose particles. These processes occur naturally or are further enhanced or reduced by human intervention. The dimensions of change are dependent primarily on the wind energy and surface properties. Since the 1970s, remote sensing imagery, both optical and radar, have been used for documentation and interpretation of the geomorphologic changes of sand dunes. Remote sensing studies of aeolian morphologies is mostly useful to document major changes, yet, subtle changes, occurring in a period of days or months in scales of centimeters, are very difficult to detect in imagery. Interferometric Synthetic Aperture Radar (InSAR) is an imaging technique for measuring Earth's surface topography and deformation. InSAR images are produced by measuring the radar phase difference between two separated antennas that view the same surface area. Classical InSAR is based on high coherence between two or more images. The output (interferogram) can show subtle changes with an accuracy of several millimeters to centimeters. Very little work has been done on measuring or identifying the changes in dunes using InSAR methods. The reason is that dunes tend to be less coherent than firm, stable, surfaces. This work aims to demonstrate how interferometric decorrelation can be used for identifying dune instability. We hypothesize and demonstrate that the loss of radar coherence over time on dunes can be used as an indication of the dune's instability. When SAR images are acquired at sufficiently close intervals one can measure the time it takes to lose coherence and associate this time with geomorphic stability. To achieve our goals, the coherence change detection method was used, in order to identify dune stability or instability and the dune activity level. The Nitzanim-Ashdod coastal dunes along the Mediterranean, 40 km south of Tel-Aviv, Israel, were chosen as a case study. The dunes in this area are of

  17. The ZpiM algorithm: a method for interferometric image reconstruction in SAR/SAS.

    PubMed

    Dias, José M B; Leitao, José M N

    2002-01-01

    This paper presents an effective algorithm for absolute phase (not simply modulo-2-pi) estimation from incomplete, noisy and modulo-2pi observations in interferometric aperture radar and sonar (InSAR/InSAS). The adopted framework is also representative of other applications such as optical interferometry, magnetic resonance imaging and diffraction tomography. The Bayesian viewpoint is adopted; the observation density is 2-pi-periodic and accounts for the interferometric pair decorrelation and system noise; the a priori probability of the absolute phase is modeled by a compound Gauss-Markov random field (CGMRF) tailored to piecewise smooth absolute phase images. We propose an iterative scheme for the computation of the maximum a posteriori probability (MAP) absolute phase estimate. Each iteration embodies a discrete optimization step (Z-step), implemented by network programming techniques and an iterative conditional modes (ICM) step (pi-step). Accordingly, the algorithm is termed ZpiM, where the letter M stands for maximization. An important contribution of the paper is the simultaneous implementation of phase unwrapping (inference of the 2pi-multiples) and smoothing (denoising of the observations). This improves considerably the accuracy of the absolute phase estimates compared to methods in which the data is low-pass filtered prior to unwrapping. A set of experimental results, comparing the proposed algorithm with alternative methods, illustrates the effectiveness of our approach. PMID:18244643

  18. The ZpiM algorithm: a method for interferometric image reconstruction in SAR/SAS.

    PubMed

    Dias, José M B; Leitao, José M N

    2002-01-01

    This paper presents an effective algorithm for absolute phase (not simply modulo-2-pi) estimation from incomplete, noisy and modulo-2pi observations in interferometric aperture radar and sonar (InSAR/InSAS). The adopted framework is also representative of other applications such as optical interferometry, magnetic resonance imaging and diffraction tomography. The Bayesian viewpoint is adopted; the observation density is 2-pi-periodic and accounts for the interferometric pair decorrelation and system noise; the a priori probability of the absolute phase is modeled by a compound Gauss-Markov random field (CGMRF) tailored to piecewise smooth absolute phase images. We propose an iterative scheme for the computation of the maximum a posteriori probability (MAP) absolute phase estimate. Each iteration embodies a discrete optimization step (Z-step), implemented by network programming techniques and an iterative conditional modes (ICM) step (pi-step). Accordingly, the algorithm is termed ZpiM, where the letter M stands for maximization. An important contribution of the paper is the simultaneous implementation of phase unwrapping (inference of the 2pi-multiples) and smoothing (denoising of the observations). This improves considerably the accuracy of the absolute phase estimates compared to methods in which the data is low-pass filtered prior to unwrapping. A set of experimental results, comparing the proposed algorithm with alternative methods, illustrates the effectiveness of our approach.

  19. Time-Domain Simulation of Along-Track Interferometric SAR for Moving Ocean Surfaces

    PubMed Central

    Yoshida, Takero; Rheem, Chang-Kyu

    2015-01-01

    A time-domain simulation of along-track interferometric synthetic aperture radar (AT-InSAR) has been developed to support ocean observations. The simulation is in the time domain and based on Bragg scattering to be applicable for moving ocean surfaces. The time-domain simulation is suitable for examining velocities of moving objects. The simulation obtains the time series of microwave backscattering as raw signals for movements of ocean surfaces. In terms of realizing Bragg scattering, the computational grid elements for generating the numerical ocean surface are set to be smaller than the wavelength of the Bragg resonant wave. In this paper, the simulation was conducted for a Bragg resonant wave and irregular waves with currents. As a result, the phases of the received signals from two antennas differ due to the movement of the numerical ocean surfaces. The phase differences shifted by currents were in good agreement with the theoretical values. Therefore, the adaptability of the simulation to observe velocities of ocean surfaces with AT-InSAR was confirmed. PMID:26067197

  20. Time-Domain Simulation of Along-Track Interferometric SAR for Moving Ocean Surfaces.

    PubMed

    Yoshida, Takero; Rheem, Chang-Kyu

    2015-01-01

    A time-domain simulation of along-track interferometric synthetic aperture radar (AT-InSAR) has been developed to support ocean observations. The simulation is in the time domain and based on Bragg scattering to be applicable for moving ocean surfaces. The time-domain simulation is suitable for examining velocities of moving objects. The simulation obtains the time series of microwave backscattering as raw signals for movements of ocean surfaces. In terms of realizing Bragg scattering, the computational grid elements for generating the numerical ocean surface are set to be smaller than the wavelength of the Bragg resonant wave. In this paper, the simulation was conducted for a Bragg resonant wave and irregular waves with currents. As a result, the phases of the received signals from two antennas differ due to the movement of the numerical ocean surfaces. The phase differences shifted by currents were in good agreement with the theoretical values. Therefore, the adaptability of the simulation to observe velocities of ocean surfaces with AT-InSAR was confirmed. PMID:26067197

  1. Measurement and Mitigation of the Ionosphere in L-Band Interferometric SAR Data

    NASA Technical Reports Server (NTRS)

    Rosen, Paul A.; Hensley, Scott; Chen, Curtis

    2010-01-01

    Satellite-based repeat-pass Interferometric Synthetic Aperture Radar (InSAR) provides a synoptic high spatial resolution perspective of Earth's changing surface, permitting one to view large areas quickly and efficiently. By measuring relative phase change from one observation to the next on a pixel-by-pixel basis, maps of deformation and change can be derived. Variability of the atmosphere and the ionosphere leads to phase/time delays that are present in the data that can mask many of the subtle deformation signatures of interest, so methods for mitigation of these effects are important. Many of these effects have been observed in existing ALOS PALSAR data, and studies are underway to characterize and mitigate the ionosphere using these data. Since the ionosphere is a dispersive medium, it is possible in principle distinguish the ionospheric signatures from the non-dispersive effects of deformation and the atmosphere. In this paper, we describe a method for mapping the ionosphere in InSAR data based on a multi-frequency split-spectrum processing technique.

  2. Time-Domain Simulation of Along-Track Interferometric SAR for Moving Ocean Surfaces.

    PubMed

    Yoshida, Takero; Rheem, Chang-Kyu

    2015-06-10

    A time-domain simulation of along-track interferometric synthetic aperture radar (AT-InSAR) has been developed to support ocean observations. The simulation is in the time domain and based on Bragg scattering to be applicable for moving ocean surfaces. The time-domain simulation is suitable for examining velocities of moving objects. The simulation obtains the time series of microwave backscattering as raw signals for movements of ocean surfaces. In terms of realizing Bragg scattering, the computational grid elements for generating the numerical ocean surface are set to be smaller than the wavelength of the Bragg resonant wave. In this paper, the simulation was conducted for a Bragg resonant wave and irregular waves with currents. As a result, the phases of the received signals from two antennas differ due to the movement of the numerical ocean surfaces. The phase differences shifted by currents were in good agreement with the theoretical values. Therefore, the adaptability of the simulation to observe velocities of ocean surfaces with AT-InSAR was confirmed.

  3. Surface Deformation of Los Humeros Caldera, Mexico, Estimated by Interferometric Synthetic Aperture Radar (InSAR).

    NASA Astrophysics Data System (ADS)

    Santos Basurto, R.; Lopez Quiroz, P.; Carrasco Nuñez, G.; Doin, M. P.

    2014-12-01

    Los Humeros caldera is located in the eastern part of the Trans-Mexican Volcanic Belt, to the north of the state of Puebla and bordering the west side of the state of Veracruz. The study of the caldera, is of great interest because there is a geothermal field currently working inside of it. In fact, Los Humeros, is the third more important geothermal field in Mexico. In this work, we used InSAR to estimate the surface deformation on the caldera, aiming to contribute to its modeling and to help preventing subsidence related hazards on the geothermal field and surroundings. On this study, we calculated 34 interferograms from 21 SAR images of the ENVISAT European Space Agency Mission. The analysis of the interferograms, allow us to detect, decorrelation of the interferometric signal increased, when time spans were greater than 70 days. Also, for those with good signal correlation, the atmospheric signal dominated the interferogram, masking completely the deformation. Moreover, residual orbital ramps were detected, in some of the calculated interferograms. An algorithm capable to remove all the interferogram signal contributions but the deformation related, has been implemented. Resulting deformation and its correlation with several variables like the geology, the hydrogeology and the seismic records, were analysed through its integration in a Geographic Information System.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  5. A Refined Algorithm On The Estimation Of Residual Motion Errors In Airborne SAR Images

    NASA Astrophysics Data System (ADS)

    Zhong, Xuelian; Xiang, Maosheng; Yue, Huanyin; Guo, Huadong

    2010-10-01

    Due to the lack of accuracy in the navigation system, residual motion errors (RMEs) frequently appear in the airborne SAR image. For very high resolution SAR imaging and repeat-pass SAR interferometry, the residual motion errors must be estimated and compensated. We have proposed a new algorithm before to estimate the residual motion errors for an individual SAR image. It exploits point-like targets distributed along the azimuth direction, and not only corrects the phase, but also improves the azimuth focusing. But the required point targets are selected by hand, which is time- and labor-consuming. In addition, the algorithm is sensitive to noises. In this paper, a refined algorithm is proposed aiming at these two shortcomings. With real X-band airborne SAR data, the feasibility and accuracy of the refined algorithm are demonstrated.

  6. Method of airborne SAR image match integrating multi-information for block adjustment

    NASA Astrophysics Data System (ADS)

    Yang, S. C.; Huang, G. M.; Zhao, Z.; Lu, L. J.

    2015-06-01

    For the automation of SAR image Block Adjustment, this paper proposed a method of SAR image matching integrating multiinformation. It takes full advantage of SAR image geometric information, feature information, gray-related information and external auxiliary terrain information for SAR image matching. And then Image Tie Points (ITPs) of Block Adjustment can be achieved automatically. The main parts of extracting ITPs automatically include: First, SAR images were rectified geometrically based on the geometric information and external auxiliary terrain information (existed DEM) before match. Second, ground grid points with a certain interval can be get in the block area and approximate ITPs were acquired based on external auxiliary terrain information. Then match reference point was extracted for homologous image blocks with Harris feature detection operator and ITPs were obtained with pyramid matching based on gray-related information. At last, ITPs were transferred from rectified images to original SAR images and used in block adjustment. In the experiment, X band airborne SAR images acquired by Chinese airborne SAR system - CASMSAR system were used to make up the block. The result had showed that the method is effective for block adjustment of SAR data.

  7. Radiometric calibration for the airborne interferometric monitor for greenhouse gases simulator.

    PubMed

    Shimota, A; Kobayashi, H; Kadokura, S

    1999-01-20

    The Advanced Earth Observation Satellite (ADEOS), launched in the summer of 1996, has a high-resolution infrared Fourier transform spectrometer, with the interferometric monitor for greenhouse gases (IMG) onboard. The IMG has a high spectral resolution of 0.1 cm(-1) for the purpose of retrieving greenhouse gas profile maps of the Earth. To meet the requirements of the retrieval algorithms for greenhouse gas profiles, atmospheric emission spectra must be calibrated to better than 1 K accuracy. Prior to the launch of the ADEOS with the IMG, we developed an airborne simulator called the tropospheric infrared interferometric sounder (TIIS). We explain the calibration procedure for the TIIS, which determines the points with the same optical path difference on interferograms for complex Fourier transformation, using the retained phase term on the calibrated spectrum. The downward atmospheric radiation, measured with the TIIS, was well calibrated using this algorithm. Furthermore, calibration of the spectra obtained from the IMG initial checkout mission observation was carried out.

  8. Estimating lava volume by precision combination of multiple baseline spaceborne and airborne interferometric synthetic aperture radar: The 1997 eruption of Okmok Volcano, Alaska

    USGS Publications Warehouse

    Lu, Zhiming; Fielding, E.; Patrick, M.R.; Trautwein, C.M.

    2003-01-01

    Interferometric synthetic aperture radar (InSAR) techniques are used to calculate the volume of extrusion at Okmok volcano, Alaska by constructing precise digital elevation models (DEMs) that represent volcano topography before and after the 1997 eruption. The posteruption DEM is generated using airborne topographic synthetic aperture radar (TOPSAR) data where a three-dimensional affine transformation is used to account for the misalignments between different DEM patches. The preeruption DEM is produced using repeat-pass European Remote Sensing satellite data; multiple interferograms are combined to reduce errors due to atmospheric variations, and deformation rates are estimated independently and removed from the interferograms used for DEM generation. The extrusive flow volume associated with the 1997 eruption of Okmok volcano is 0.154 ?? 0.025 km3. The thickest portion is approximately 50 m, although field measurements of the flow margin's height do not exceed 20 m. The in situ measurements at lava edges are not representative of the total thickness, and precise DEM data are absolutely essential to calculate eruption volume based on lava thickness estimations. This study is an example that demonstrates how InSAR will play a significant role in studying volcanoes in remote areas.

  9. Tropical-Forest Profiles and Biomass from TanDEM-X, Single-Baseline Interferometric SAR: InSAR Performance at Higher Frequencies and Bandwidths

    NASA Astrophysics Data System (ADS)

    Treuhaft, R. N.; Goncalves, F. G.; Neumann, M.; Keller, M. M.; Santos, J. R.

    2015-12-01

    The principal method for remotely sensing forest biomass, particularly high-biomass tropical forests, is to measure vertical structural properties of the forest and relate them to biomass. Interferometric SAR (InSAR) and lidar are the two principal technologies applied to this task. InSAR profile information is constrained in the traditional, look-averaged analysis, because it measures the vertical Fourier transform of the radar power at one and only one vertical frequency specified by the baseline. Lidar produces a full profile, including all Fourier frequencies—all vertical scales of fluctuation. In TanDEM-X data over tropical forests at the Tapajos National Forest, Brazil, we show the results of potentially improving InSAR's Fourier coverage. This is done by estimating many Fourier frequencies with a single baseline, based on the assumption that sampling of the phase height of small (~1.5 m x 2.5 m) looks of TanDEM-X is equivalent to sampling the vertical structure of the forest; a spatial ergodicity. We show a similarity between the distribution of InSAR look-phase-heights (LPH) and lidar and field profiles over 0.25-ha areas. Using Fourier transforms of the histogram of LPH over 0.25 ha areas, biomass estimation improved by about 17% over using InSAR coherence and mean forest height, making it competitive with some lidar results. The RMS of biomasses estimated about field biomass was 48 Mg/ha, with biomasses as high as 430 Mg/ha, and an average of 174 Mg/ha. Perhaps LPH distributions bear a similarity to lidar and field profiles because shorter wavelengths (~3 cm) can penetrate holes in the canopy to scatter off a sample of the vegetation with each look. This "hole mechanism" favors higher frequencies, which are able to penetrate smaller holes. Because they increase the number of look samples, higher bandwidths are also preferred.

  10. Ground truth measurement for the analysis of airborne SAR data recorded over Oberpfaffenhofen, FRG, 1989

    NASA Technical Reports Server (NTRS)

    Bayer, T.; Wieneke, F.; Winter, R.

    1990-01-01

    As a preliminary investigation to the joint multiparameter SIR-C/X-SAR shuttle experiment of NASA/JPL (USA), DLR (FRG), and PSN (Italy) which is scheduled for the year 1992 an airborne SAR campaign was conducted over Oberpfaffenhofen, FRG, in August 1989. Primarily this campaign was planned to test and verify equipment and algorithms developed at the DLR to calibrate multifrequency polarimetric SAR data. Oberpfaffenhofen is designated as one of the super test sites for the SIR-C/X-SAR experiment which will be imaged under all circumstances except severe mission errors. A super test site drives radar parameters and look directions and the recorded SAR data will be calibrated. In addition ancillary data will be available for the site. During the airborne STAR campaign conducted in the week of August 14th 1989 various sensor types were used to record remote sensing data over the calibration test site and its vicinity: the polarimetric DC-8 JPL-SAR (P-, L-, C-band), the DLR airborne SAR (C-, X-band), color infrared aerial photography (DLR), and the truck-mounted scatterometer (C- and X-band) of the Institute for Navigation, University of Stuttgart (INS). Because of this variety of different sensor types used and out of the fact that sufficiently large forested and agriculturally used areas were planned to be covered by these sensors, the interest of several German research groups involved in investigations concerning SAR land applications arose. The following groups carried out different ground-truth measurements: University of Bonn, Institute for plant cultivation (plant morphology and moisture content); University of Braunschweig, Institute for Geography (soil moisture and surface roughness); University of Freiburg, Institute for Geography (dielectric soil properties, landuse); and University of Munich, Institute for Geography (landuse inventory, plant, surface, and soil parameters). This paper presents the joint ground truth activities of the Institute for Geography

  11. Split-Band Interferometric SAR Processing Using TanDEM-X Data

    NASA Astrophysics Data System (ADS)

    De Rauw, Dominique; Kervyn, Francois; d'Oreye, Nicolas; Smets, Benoit; Albino, Fabien; Barbier, Christian

    2015-05-01

    Most recent SAR sensors use wide band signals to achieve metric range resolution. One can also take advantage of wide band to split it into sub-bands and generate several lower-resolution images, centered on slightly different frequencies, from a single acquisition. This process, named Multi Chromatic Analysis (MCA) corresponds to performing a spectral analysis of SAR images. Split-Band SAR interferometry (SBInSAR) is based on spectral analysis performed on each image of an InSAR pair, yielding a stack of sub-band interferograms. Scatterers keeping a coherent behaviour in each sub-band interferogram show a phase that varies linearly with the carrier frequency, the slope being proportional to the absolute optical path difference. This potentially solves the problems of phase unwrapping on a pixel-per-pixel basis. In this paper, we present an SBInSAR processor and its application using TanDEM-X data over the Nyiragongo volcano.

  12. Using Regional GPS Network Atmospheric Models for Mitigating Errors in Interferometric Synthetic Aperture Radar (InSAR) Images

    NASA Astrophysics Data System (ADS)

    Reuveni, Y.; Bock, Y.; Tong, X.; Moore, A. W.

    2015-12-01

    Interferometric Synthetic Aperture Radar (InSAR) measurements provide valuable information for obtaining Earth surface deformation and topography at high spatial resolution for crustal deformation studies. Similar to Global Positioning System (GPS), InSAR phase measurements are affected by the Earth's ionospheric and tropospheric layers as the electromagnetic signals significantly refract while propagating through the different layers. While electromagnetic signals propagating through the neutral atmosphere are affected primarily by the pressure, temperature, and water vapor content of atmospheric gases, the propagation through the ionosphere is mainly affected by the number of free electrons along the signal path. Here, we present the use of dense regional GPS networks for extracting tropospheric zenith delays and ionospheric Total Electron Content (TEC) maps in order to reduce the noise levels in the phase measurement of the InSAR images. The results show significant reduction in the RMS values when simultaneously combining the two corrections, both at short time periods where no surface deformation is expected, and at longer periods, where imaging of crustal deformation, such as the ground subsidence and aseismic fault creep, is enhanced.

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

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  14. Merging Airborne LIDAR Data and Satellite SAR Data for Building Classification

    NASA Astrophysics Data System (ADS)

    Yamamoto, T.; Nakagawa, M.

    2015-05-01

    A frequent map revision is required in GIS applications, such as disaster prevention and urban planning. In general, airborne photogrammetry and LIDAR measurements are applied to geometrical data acquisition for automated map generation and revision. However, attribute data acquisition and classification depend on manual editing works including ground surveys. In general, airborne photogrammetry and LiDAR measurements are applied to geometrical data acquisition for automated map generation and revision. However, these approaches classify geometrical attributes. Moreover, ground survey and manual editing works are finally required in attribute data classification. On the other hand, although geometrical data extraction is difficult, SAR data have a possibility to automate the attribute data acquisition and classification. The SAR data represent microwave reflections on various surfaces of ground and buildings. There are many researches related to monitoring activities of disaster, vegetation, and urban. Moreover, we have an opportunity to acquire higher resolution data in urban areas with new sensors, such as ALOS2 PALSAR2. Therefore, in this study, we focus on an integration of airborne LIDAR data and satellite SAR data for building extraction and classification.

  15. Estimation of bare soil evaporation using multifrequency airborne SAR

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

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

    SciTech Connect

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

    1996-01-16

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

  17. Detecting coal fires in China using Differential Interferometric Synthetic Aperture Radar (InSAR)

    NASA Astrophysics Data System (ADS)

    Hoffmann, J.; Roth, A.; Voigt, S.

    2004-06-01

    We investigate the feasibility of detecting fires in subsurface coal deposits through InSAR observations of accompa- nying surface displacements. Uncontrolled burning of subsurface coal seams have been reported from many locations around the world. In northern China alone, more than 10 Million tons (Mt) of coal are estimated to burn every year. This has massive implications for the regional economy and ecology. In fighting these fires and controlling burning coal seams the timely and reliable detection and mapping of the affected regions is critical. However, this has proven to be ex- tremely difficult in the often remote regions of northern China, where many of the fires have been caused by uncontrolled, small-scale mining operations. Both volume change of the burning coal and thermal effects in the adjacent rock mass are expected to cause measurable surface displacements and numerous reports of collapses of the earth's surface exist. Unfortunately, reliable data on surface deformation accompanying the fires are not available. Nevertheless, theoretical considerations and individual reports suggest that subsidence mapping using differential InSAR may be a suitable tool to detect burning regions and map the spatial extent of the affected areas. Though topography, temporal decorrelation, and poor data coverage complicate the analysis we have identified several localized areas of subsidence in the region. Here we discuss the potential and limitations of using InSAR for coal-fire detection in northern China.

  18. Blind estimation of interferometric SAR phase images through fuzzy matching-pursuits

    NASA Astrophysics Data System (ADS)

    Aiazzi, Bruno; Alparone, Luciano; Baronti, Stefano; Bianchini, Massimo

    2002-01-01

    This paper presents an original application of fuzzy logic to restoration of interferometric phase images from IFSAR, which are affected by zero-mean uncorrelated noise, whose variance depends on the underlying coherence, thus resulting in a nonstationary random process. Spatial filtering of the phase noise is recommended, either before phase unwrapping is accomplished, or simultaneously with it. In fact, phase unwrapping basically relies on a smoothness constraint of the phase field, which is severely hampered by the noise. Space-varying linear MMSE estimation is stated as a problem of matching pursuits, in which the estimator is obtained as an expansion in series of a finite number of prototype estimators, fitting the spatial features of the different statistical classes encountered, e.g., fringes, and steep slope areas. Such estimators are calculated in a fuzzy fashion through an automatic training procedure. The space-varying coefficients of the expansion are stated as degrees of fuzzy membership of a pixel to each of the estimators. Besides the fact that neither a priori knowledge on the noise variance is required, nor a particular signal model is assumed, a performance comparison on simulated noisy images highlights the advantages of the proposed approach. Results on simulated noisy versions of Lenna show a steady SNR improvement of almost 3 dB over Kuan's LLMMSE filtering, irrespective of noise model and intensity. Applications of the proposed filter to interferometric phase images demonstrate a superior ability of preserving fringes discontinuities, together with an effective smoothing performance, irrespective of local coherence characteristics.

  19. Design criteria and comparison between conventional and subaperture SAR processing in airborne systems

    NASA Astrophysics Data System (ADS)

    Prats, Pau; Bara, Marc; Broquetas, Antoni

    2002-02-01

    This paper compares two different approaches for designing airborne SAR systems. The first one is the most common where conventional processing is employed, and therefore wide antenna beams are to be used in order to avoid ambiguities in the final image due to attitude variations. A second approach is proposed to lower the requirements such system imposes based on subaperture processing. The idea is to follow the azimuth variations of the Doppler centroid, without increasing the hardware requirements of the system. As it is shown in this paper, this processing procedure must be complemented with precise radiometric corrections, because the platform may experience small attitude variations, which could increase/decrease the target observation time, inducing a significant azimuth modulation in the final image. This leads to the definition of a new criterion concerning maximum attitude deviations for an airborne platform.

  20. General adaptive-neighborhood technique for improving synthetic aperture radar interferometric coherence estimation.

    PubMed

    Vasile, Gabriel; Trouvé, Emmanuel; Ciuc, Mihai; Buzuloiu, Vasile

    2004-08-01

    A new method for filtering the coherence map issued from synthetic aperture radar (SAR) interferometric data is presented. For each pixel of the interferogram, an adaptive neighborhood is determined by a region-growing technique driven by the information provided by the amplitude images. Then pixels in the derived adaptive neighborhood are complex averaged to yield the filtered value of the coherence, after a phase-compensation step is performed. An extension of the algorithm is proposed for polarimetric interferometric SAR images. The proposed method has been applied to both European Remote Sensing (ERS) satellite SAR images and airborne high-resolution polarimetric interferometric SAR images. Both subjective and objective performance analysis, including coherence edge detection, shows that the proposed method provides better results than the standard phase-compensated fixed multilook filter and the Lee adaptive coherence filter.

  1. MAPSAR Image Simulation Based on L-band Polarimetric Data from the SAR-R99B Airborne Sensor (SIVAM System)

    PubMed Central

    Mura, José Claudio; Paradella, Waldir Renato; Dutra, Luciano Vieira; dos Santos, João Roberto; Rudorff, Bernardo Friedrich Theodor; de Miranda, Fernando Pellon; da Silva, Mario Marcos Quintino; da Silva, Wagner Fernando

    2009-01-01

    This paper describes the methodology applied to generate simulated multipolarized L-band SAR images of the MAPSAR (Multi-Application Purpose SAR) satellite from the airborne SAR R99B sensor (SIVAM System). MAPSAR is a feasibility study conducted by INPE (National Institute for Space Research) and DLR (German Aerospace Center) targeting a satellite L-band SAR innovative mission for assessment, management and monitoring of natural resources. Examples of simulated products and their applications are briefly discussed. PMID:22389590

  2. Analysis of catchment hydrogeomorphology and vegetation patterns based on a differential GPS survey and interferometric SAR

    NASA Astrophysics Data System (ADS)

    Gutiérrez-Jurado, H. A.; Vivoni, E. R.; Ennin, F.

    2007-12-01

    To better understand the effect of vegetation on hydrogeomorphic processes, detailed studies on terrain properties and vegetation patterns performed at the catchment scale are needed. These studies require high resolution topography data (<5 m) in order to accurately capture the variability of the terrain and to successfully link it to vegetation patterns. Hydrologic and terrain analyses were performed on a small (~0.1 km2) first order semiarid basin in central New Mexico. The catchment exhibits opposing north versus south facing slopes, giving rise to different ecosystems and geomorphic properties, with an east facing headslope comprising an ecotonal boundary. A high precision (5 cm in x, y, z) differential global positioning system (GPS) was used to generate a digital elevation model (DEM) of the catchment using nearly 6,000 independent observations. This high resolution DEM is used to perform a set of topography-based analyses on the current hydrologic and geomorphic properties of the basin. We discuss the GPS survey methods employed in the field, data post- processing and various interpolation approaches utilized for gridding the point data. We then perform a series of hydrogeomorphic analyses based on different terrain indices such as the TOPMODEL index, and address the issue of scale by comparing results from the GPS derived DEM with a 10 m DEM from the Interferometric Synthetic Aperture Radar (IFSAR). Finally, a 1 m orthophoto is used to perform a supervised classification of the spatial arrangement of vegetation in the area and the relationship to the hydrologic and terrain indices is explored. Our results indicate substantial differences exist in terrain properties derived from GPS and IFSAR products. These differences can potentially lead to divergent conclusions on the investigation of vegetation pattern influences on hydrogeomorphic properties of basins. The results obtained point to the need for higher resolution DEMs than IFSAR for studying vegetation

  3. Arizona Department of Water Resources use of ALOS Interferometric Synthetic Aperture Radar (InSAR) data to Identify Areas of Land Subsidence in Southeastern Arizona

    NASA Astrophysics Data System (ADS)

    Conway, B. D.

    2011-12-01

    The Arizona Department of Water Resources (ADWR) has been collecting, processing, and analyzing Interferometric Synthetic Aperture Radar (InSAR) data since 2005. The Alaska Satellite Facility's Americas ALOS Data Node (AADN) has provided ADWR's InSAR program with the necessary data to identify new land subsidence features in Southeastern Arizona within Cochise County. ADWR has used the ALOS InSAR data in conjunction with ADWR groundwater level data to better understand the groundwater conditions in relation to the current land subsidence data and attempt to better understand the complex basin hydrology of the area. ADWR and the Arizona Geological Survey (AZGS) have used the ALOS InSAR data to also identify areas where conditions may exist for earth fissure formation. Further ground investigations by the AZGS have revealed unmapped earth fissures in potential earth fissure risk areas identified by ALOS InSAR data. Previously mapped earth fissures by the AZGS also fall within some of these earth fissure risk areas.

  4. Ship Detection and Sea Clutter Characterisation Using X&L-Band Full-Folarimetric Airborne SAR Data

    NASA Astrophysics Data System (ADS)

    Angelliaume, S.; Martineau, Ph.; Durand, Ph.; Cussac, T.

    2013-03-01

    The interest for maritime surveillance and ship detection in particular has been growing during the last years. In this context, space borne SAR systems may contribute to the improvement of security and safety at sea. In order to allow observation of non-cooperative boats, the revisit times of such systems must be compatible with the objectives of reactivity of maritime surveillance. Under CNES (French Space Agency) initiative, an airborne campaign using the ONERA Airborne SAR SETHI took place over the Atlantic Ocean. The main objective of this dedicated campaign of acquisition was to perform very precise measurements of sea clutter and ship Radar Cross Sections (RCS) at low grazing angle. This paper intend to present this airborne campaign of acquisition dedicated to maritime surveillance, analysis and first results at X band about sea clutter and ship RCS experimental measurements.

  5. High-Accuracy Elevation Data at Large Scales from Airborne Single-Pass SAR Interferometry

    NASA Astrophysics Data System (ADS)

    Schumann, Guy; Moller, Delwyn; Mentgen, Felix

    2015-12-01

    Digital elevation models (DEMs) are essential data sets for disaster risk management and humanitarian relief services as well as many environmental process models. At present, on the hand, globally available DEMs only meet the basic requirements and for many services and modeling studies are not of high enough spatial resolution and lack accuracy in the vertical. On the other hand, LiDAR-DEMs are of very high spatial resolution and great vertical accuracy but acquisition operations can be very costly for spatial scales larger than a couple of hundred square km and also have severe limitations in wetland areas and under cloudy and rainy conditions. The ideal situation would thus be to have a DEM technology that allows larger spatial coverage than LiDAR but without compromising resolution and vertical accuracy and still performing under some adverse weather conditions and at a reasonable cost. In this paper, we present a novel single pass In-SAR technology for airborne vehicles that is cost-effective and can generate DEMs with a vertical error of around 0.3 m for an average spatial resolution of 3 m. To demonstrate this capability, we compare a sample single-pass In-SAR Ka-band DEM of the California Central Valley from the NASA/JPL airborne GLISTIN-A to a high-resolution LiDAR DEM. We also perform a simple sensitivity analysis to floodplain inundation. Based on the findings of our analysis, we argue that this type of technology can and should be used to replace large regions of globally available lower resolution DEMs, particularly in coastal, delta and floodplain areas where a high number of assets, habitats and lives are at risk from natural disasters. We conclude with a discussion on requirements, advantages and caveats in terms of instrument and data processing.

  6. Three-frequency, polarimetric, airborne SAR observations of the Greenland ice sheet

    NASA Technical Reports Server (NTRS)

    Rignot, E.; Vanzyl, J. J.; Jezek, K.

    1994-01-01

    Synthetic aperture radar (SAR) images of the Greenland ice sheet collected by an airborne system clearly reveal the four melting facies of this sheet defined 30 years ago from snow stratigraphy studies by glaciologists. In particular, the radar echoes from the percolation facies have radiometric and polarimetric characteristics that are unique among terrestrial surfaces, but that resemble the exotic radar echoes recorded from the icy Galilean satellites. There, the radar signals interact with subsurface, massive ice features created in the cold, dry snow by seasonal melting and refreezing events. The subsurface features act as efficient reflectors of the incident radiation most likely via internal reflections. In the soaked-snow facies, the radar reflectivity is much lower because radar signals are attenuated by the wetter snow before they can interact with subsurface structures. Inversion algorithms to derive geophysical information from the SAR data are developed in both cases to estimate snow wetness in the soaked-snow facies and the mass of ice water retained in the percolation facies.

  7. Lineaments from airborne SAR images and the 1988 Saguenay earthquake, Quebec, Canada

    SciTech Connect

    Roy, D.W.; Schmitt, L.; Woussen, G.; Duberger, R. )

    1993-08-01

    Airborne SAR images provided essential clues to the tectonic setting of (1) the MbLg 6.5 Saguenay earthquake of 25 November 1988, (2) the Charlevoix-Kamouraska seismic source zone, and (3) some of the low *eve* seismic activity in the Eastern seismic background zone of Canada. The event occurred in the southeastern part of the Canadian Shield in an area where the boundary between the Saguenay graben and the Jacques Cartier horst is not well defined. These two tectonic blocks are both associated with the Iapetan St-Lawrence rift. These blocks exhibit several important structural breaks and distinct domains defined by the lineament orientations, densities, and habits. Outcrop observations confirm that several lineament sets correspond to Precambrian ductile shear zones reactivated as brittle faults during the Phanerozoic. In addition, the northeast and southwest limits of recent seismic activity in the Charlevoix-Kamouraska zone correspond to major elements of the fracture pattern identified on the SAR images. These fractures appear to be related to the interaction of the Charlevoix astrobleme with the tectonic features of the area. 20 refs.

  8. Flood disaster monitoring in Thailand by using a airborne L-band SAR: Polarimetric and interferometry Synthetic Aperture Radar with L-band(Pi-SAR-L)

    NASA Astrophysics Data System (ADS)

    Kawano, N.; Sobue, S.; Shimada, M.; Ohyoshi, K.

    2012-04-01

    It was heavy rainfall around the northern region of Thailand from July to September 2011, which caused flood disaster to quite wide region of Thailand, it finally reached to the Bangkok central in the end of October 2011. Japan Aerospace Exploration Agency (JAXA) conducted an emergency observation by using a airborne L-band SAR: Polarimetric and interferometry Synthetic Aperture Radar with L-band(Pi-SAR-L) from 5th to 27th November to monitor flood area. Pi-SAR-L has a center frequency of 1271.5 MHz, a band width of 50 MHz, a slant range resolution of 3 m, and an acquisition swath of 15 km on the ground. Pi-SAR-L is boarded on an aircraft of the Gulfstream-II operated by the Diamond Air Service(DAS), Japan, and the Gulfstream-II was ferried to the Chieng-Mai airport in the North Thailand, from Japan. In our presentation, we will show flood area around Bangkok and its variations detected by Pi-SAR-L

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Hanson, Bradford C.; Dellwig, Louis F.

    1988-01-01

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

  11. Three-dimensional surface deformation derived from airborne interferometric UAVSAR: Application to the Slumgullion Landslide

    NASA Astrophysics Data System (ADS)

    Delbridge, Brent G.; Bürgmann, Roland; Fielding, Eric; Hensley, Scott; Schulz, William H.

    2016-05-01

    In order to provide surface geodetic measurements with "landslide-wide" spatial coverage, we develop and validate a method for the characterization of 3-D surface deformation using the unique capabilities of the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) airborne repeat-pass radar interferometry system. We apply our method at the well-studied Slumgullion Landslide, which is 3.9 km long and moves persistently at rates up to ˜2 cm/day. A comparison with concurrent GPS measurements validates this method and shows that it provides reliable and accurate 3-D surface deformation measurements. The UAVSAR-derived vector velocity field measurements accurately capture the sharp boundaries defining previously identified kinematic units and geomorphic domains within the landslide. We acquired data across the landslide during spring and summer and identify that the landslide moves more slowly during summer except at its head, presumably in response to spatiotemporal variations in snowmelt infiltration. In order to constrain the mechanics controlling landslide motion from surface velocity measurements, we present an inversion framework for the extraction of slide thickness and basal geometry from dense 3-D surface velocity fields. We find that the average depth of the Slumgullion Landslide is 7.5 m, several meters less than previous depth estimates. We show that by considering a viscoplastic rheology, we can derive tighter theoretical bounds on the rheological parameter relating mean horizontal flow rate to surface velocity. Using inclinometer data for slow-moving, clay-rich landslides across the globe, we find a consistent value for the rheological parameter of 0.85 ± 0.08.

  12. Interferometric synthetic aperture radar imagery of the Gulf Stream

    NASA Technical Reports Server (NTRS)

    Ainsworth, T. L.; Cannella, M. E.; Jansen, R. W.; Chubb, S. R.; Carande, R. E.; Foley, E. W.; Goldstein, R. M.; Valenzuela, G. R.

    1993-01-01

    The advent of interferometric synthetic aperture radar (INSAR) imagery brought to the ocean remote sensing field techniques used in radio astronomy. Whilst details of the interferometry differ between the two fields, the basic idea is the same: Use the phase information arising from positional differences of the radar receivers and/or transmitters to probe remote structures. The interferometric image is formed from two complex synthetic aperture radar (SAR) images. These two images are of the same area but separated in time. Typically the time between these images is very short -- approximately 50 msec for the L-band AIRSAR (Airborne SAR). During this short period the radar scatterers on the ocean surface do not have time to significantly decorrelate. Hence the two SAR images will have the same amplitude, since both obtain the radar backscatter from essentially the same object. Although the ocean surface structure does not significantly decorrelate in 50 msec, surface features do have time to move. It is precisely the translation of scattering features across the ocean surface which gives rise to phase differences between the two SAR images. This phase difference is directly proportional to the range velocity of surface scatterers. The constant of proportionality is dependent upon the interferometric mode of operation.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  14. Quantification of L-band InSAR decorrelation in volcanic terrains using airborne LiDAR data

    NASA Astrophysics Data System (ADS)

    Sedze, M.; Heggy, E.; Jacquemoud, S.; Bretar, F.

    2011-12-01

    Repeat-pass InSAR LOS measurements of the Piton de La Fournaise (La Reunion Island, France) suffer from substantial phase decorrelation due to the occurrence of vegetation and ash deposits on the caldera and slopes of the edifice. To correct this deficiency, we combine normalized airborne LiDAR (Light Detection and Ranging) intensity data with spaceborne InSAR coherence images from ALOS PALSAR L-band acquired over the volcano in 2008 and 2009, following the 2007 major eruption. The fusion of the two data sets improves the calculation of coherence and the textural classification of different volcanic surfaces. For future missions considering both InSAR and/or LiDAR such as DESDynI (Deformation, Ecosystem Structure and Dynamics of Ice), such data fusion studies can provide a better analysis of the spatiotemporal variations in InSAR coherence in order to enhance the monitoring of pre-eruptive ground displacements. The airborne surveys conducted in 2008 and 2009, cover different types of vegetation and terrain roughness on the central and western parts of the volcano. The topographic data are first processed to generate a high-resolution digital terrain model (DTM) of the volcanic edifice with elevation accuracy better than 1 m. For our purposes, the phase variations caused by the surface relief can be eliminated using the LiDAR-derived DTM. Then normalized LiDAR intensities are correlated to the L-band polarimetric coherence for different zones of the volcano to assess the LiDAR-InSAR statistical behavior of different lava flows, pyroclastics, and vegetated surfaces. Results suggest that each volcanic terrain type is characterized by a unique LiDAR-InSAR histogram pattern. We identified four LiDAR-InSAR distinguished relations: (1) pahoehoe lava flow surfaces show an agglomerate histogram pattern which may be explained by low surface scattering and low wave penetration into the geological medium; (2) eroded a'a lava surfaces is characterized by high standard deviation

  15. Imaging fault slip variation along the central San Andreas fault from satellite, airborne InSAR and GPS

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Lundgren, P.; Fielding, E. J.; Hensley, S.

    2011-12-01

    The improved spatiotemporal resolution of surface deformation from recent satellite and airborne InSAR measurements provides great potential to improve our understanding of faulting processes and earthquake hazard for a given fault system. A major plate boundary fault in central California, the central San Andreas fault (CSAF) displays a spectrum of complex fault slip behaviors with creeping in its central segment that decreases towards its northwest and southeast ends where the fault transitions to being locked. In the north the CSAF branches into two sub-parallel faults that are both actively accommodating plate motion. To the south, near the Parkfield transition, large earthquakes have occurred with at least six Mw ~6.0 events since 1857, most recently in 2004. To understand the complexity and variety of fault slip behaviors and fault mechanics, we integrate satellite and airborne synthetic aperture radar (SAR) repeat pass interferometry (RPI) observations, with GPS measurements from the Plate Boundary Observatory (PBO) and regional campaign networks to estimate fault slip and shallow slip deficits along the CSAF. Existing C-band ERS-1/2, Envisat and Radarsat SAR data provide long archives of SAR data over the region but are subject to severe decorrelation. The Japan Aerospace Exploration Agency's ALOS satellite has made less frequent acquisitions (5-6/yr per track) since 2006 but its PALSAR L-band sensor provides much improved coherence compared to shorter wavelength radar data. More recently, the NASA UAVSAR airborne SAR has repeated fault perpendicular adjacent swaths imaged from opposing look directions and fault parallel swath flights over the CSAF over the past three years and provides an improved imaging of fault slip related deformation at finer spatial resolution than previous platforms (~6m at 12 azimuth x 3 range looks). Compared to C-band instruments, the UAVSAR provides nearly complete spatial coverage. Compared to the ALOS mission, the UAVSAR

  16. Constraints on deformation of Hekla volcano, Iceland, 2011-2014, from time-series interferometric analysis of COSMO-SkyMed SAR data and Singular Spectrum Analysis (SSA)

    NASA Astrophysics Data System (ADS)

    Dumont, Stéphanie; Sigmundsson, Freysteinn; Parks, Michelle; Ófeigsson, Benedikt; Bagnardi, Marco; Hooper, Andy; Einarsson, Páll; Wittmann, Werner

    2015-04-01

    Hekla volcano is one of the most active volcanoes in Iceland with 18 summit eruptions during the last 1100 years. Since 1970, the volcano has erupted approximatively every 10 years: in 1980-1981, 1991 and 2000. A special feature of Hekla volcano is its aseismic behavior except within 2 hours before these eruptions. However, in 2013 and 2014, some seismic swarms were detected within a 5km radius centered on the volcano, which is unusual for any time period between eruptions. No change in the ground deformation (continuous borehole strainmeter and ground-based GPS), was observed during these events. This year, will be the fifteenth year without an eruption at Hekla, the extended period (since the last eruption) raises the following question: Has the magma plumbing system or the rate of melt supply changed since the last eruption? What is the state of the volcano? What does it imply for its eruptive cycle? To address these questions, we study ground deformation around Hekla volcano using time-series analysis. We analyzed COSMO-SkyMed SAR data acquired between 2011 and 2014 using the Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) approach for both ascending and descending configurations. As highlighted by previous studies of ground deformation around Hekla, the small deformation rate distributed over a large area increases the importance of the noise reduction process. Once the signal to noise ratio is improved, both time-series display a dominant subsidence signal. The subsiding areas correlate with lava flows extruded during the 2000 eruption. A small inflation signal is more difficult to substantiate from the SAR data alone. For this reason further investigation of source characteristics using a Singular Spectrum Analysis (SSA) is required. SSA is an empirical based decomposition of the signal. This decomposition is applied on a trajectory matrix, called a Hankel matrix (similar to a cross-lag correlation matrix). This method enables the

  17. A Methodology to Validate the InSAR Derived Displacement Field of the September 7th, 1999 Athens Earthquake Using Terrestrial Surveying. Improvement of the Assessed Deformation Field by Interferometric Stacking

    PubMed Central

    Kotsis, Ioannis; Kontoes, Charalabos; Paradissis, Dimitrios; Karamitsos, Spyros; Elias, Panagiotis; Papoutsis, Ioannis

    2008-01-01

    The primary objective of this paper is the evaluation of the InSAR derived displacement field caused by the 07/09/1999 Athens earthquake, using as reference an external data source provided by terrestrial surveying along the Mornos river open aqueduct. To accomplish this, a processing chain to render comparable the leveling measurements and the interferometric derived measurements has been developed. The distinct steps proposed include a solution for reducing the orbital and atmospheric interferometric fringes and an innovative method to compute the actual InSAR estimated vertical ground subsidence, for direct comparison with the leveling data. Results indicate that the modeled deformation derived from a series of stacked interferograms, falls entirely within the confidence interval assessed for the terrestrial surveying data.

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

    PubMed

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

    2016-06-13

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

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

    PubMed

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

    2016-01-01

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

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

    PubMed Central

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

    2016-01-01

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

  1. Fusion of LADAR with SAR for precision strike

    SciTech Connect

    Cress, D.H.; Muguira, M.R.

    1995-03-01

    This paper presents a concept for fusing 3-dimensional image reconnaissance data with LADAR imagery for aim point refinement. The approach is applicable to fixed or quasi-fixed targets. Quasi-fixed targets are targets that are not expected to be moved between the time of reconnaissance and the time of target engagement. The 3-dimensional image data is presumed to come from standoff reconnaissance assets tens to hundreds of kilometers from the target area or acquisitions prior to hostilities. Examples are synthetic aperture radar (SAR) or stereoprocessed satellite imagery. SAR can be used to generate a 3-dimensional map of the surface through processing of data acquired with conventional SAR acquired using two closely spaced, parallel reconnaissance paths, either airborne or satellite based. Alternatively, a specialized airborne SAR having two receiving antennas may be used for data acquisition. The data sets used in this analysis are: (1) LADAR data acquired using a Hughes-Danbury system flown over a portion of Kirtland AFB during the period September 15--16, 1993; (2) two pass interferometric SAR data flown over a terrain-dominated area of Kirtland AFB; (3) 3-dimensional mapping of an urban-dominated area of the Sandia National Laboratories and adjacent cultural area extracted from aerial photography by Vexcel Corporation; (4) LADAR data acquired at Eglin AFB under Wright Laboratory`s Advanced Technology Ladar System (ATLAS) program using a 60 {mu}J, 75 KHz Co{sub 2} laser; and (5) two pass interferometric SAR data generated by Sandia`s STRIP DCS (Data Collection System) radar corresponding to the ATLAS LADAR data. The cultural data set was used in the urban area rather than SAR because high quality interferometric SAR data were not available for the urban-type area.

  2. Airborne & SAR Synergy Reveals the 3D Structure of Air Bubble Entrainment in Internal Waves and Frontal Zones

    NASA Astrophysics Data System (ADS)

    da Silva, J. C. B.; Magalhaes, J. M.; Batista, M.; Gostiaux, L.; Gerkema, T.; New, A. L.

    2013-03-01

    Internal waves are now recognised as an important mixing mechanism in the ocean. Mixing at the base of the mixed layer and in the seasonal thermocline affects the properties of those water masses which define the exchange of heat and freshwater between the atmosphere and ocean. The breaking of Internal Solitary Waves (ISWs) contributes significantly to turbulent mixing in the near-surface layers, through the continual triggering of instabilities as they propagate and shoal towards the coast or shallow topography. Here we report some results of the EU funded project A.NEW (Airborne observations of Nonlinear Evolution of internal Waves generated by internal tidal beams). The airborne capabilities to observe small scale structure of breaking internal waves in the near-shore zone has been demonstrated in recent studies (e.g. Marmorino et al., 2008). In particular, sea surface thermal signatures of shoaling ISWs have revealed the turbulent character of these structures in the form of surface “boil” features. On the other hand, some in situ measurements of internal waves and theoretical work suggest subsurface entrainment of air bubbles in the convergence zones of ISWs (Serebryany and Galybin, 2009; Grimshaw et al., 2010). We conducted airborne remote sensing observations in the coastal zone off the west Iberian Peninsula (off Lisbon, Portugal) using high resolution imaging sensors: LiDAR (Light Detection And Ranging), hyperspectral cameras (Eagle and Hawk) and thermal infrared imaging (TABI-320). These measurements were planned based on previous SAR observations in the region, which included also near-real time SAR overpasses (ESA project AOPT-2423 and TerraSAR-X project OCE-0056). The airborne measurements were conducted from board the NERC (Natural Environmental Research Centre) Do 228 aircraft in the summer of 2010. The TABI-320 thermal airborne broadband imager can distinguish temperature differences as small as one-twentieth of a degree and operates in the

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  5. Deformation Time-Series of the Lost-Hills Oil Field using a Multi-Baseline Interferometric SAR Inversion Algorithm with Finite Difference Smoothing Constraints

    NASA Astrophysics Data System (ADS)

    Werner, C. L.; Wegmüller, U.; Strozzi, T.

    2012-12-01

    The Lost-Hills oil field located in Kern County,California ranks sixth in total remaining reserves in California. Hundreds of densely packed wells characterize the field with one well every 5000 to 20000 square meters. Subsidence due to oil extraction can be grater than 10 cm/year and is highly variable both in space and time. The RADARSAT-1 SAR satellite collected data over this area with a 24-day repeat during a 2 year period spanning 2002-2004. Relatively high interferometric correlation makes this an excellent region for development and test of deformation time-series inversion algorithms. Errors in deformation time series derived from a stack of differential interferograms are primarily due to errors in the digital terrain model, interferometric baselines, variability in tropospheric delay, thermal noise and phase unwrapping errors. Particularly challenging is separation of non-linear deformation from variations in troposphere delay and phase unwrapping errors. In our algorithm a subset of interferometric pairs is selected from a set of N radar acquisitions based on criteria of connectivity, time interval, and perpendicular baseline. When possible, the subset consists of temporally connected interferograms, otherwise the different groups of interferograms are selected to overlap in time. The maximum time interval is constrained to be less than a threshold value to minimize phase gradients due to deformation as well as minimize temporal decorrelation. Large baselines are also avoided to minimize the consequence of DEM errors on the interferometric phase. Based on an extension of the SVD based inversion described by Lee et al. ( USGS Professional Paper 1769), Schmidt and Burgmann (JGR, 2003), and the earlier work of Berardino (TGRS, 2002), our algorithm combines estimation of the DEM height error with a set of finite difference smoothing constraints. A set of linear equations are formulated for each spatial point that are functions of the deformation velocities

  6. Surface Parameter Estimation using Interferometric Coherences between Different Polarisations

    NASA Astrophysics Data System (ADS)

    Hajnsek, I.; Alvarez-Perez, J.-L.; Papathanassiou, K. P.; Moreira, A.; Cloude, S. R.

    2003-04-01

    In this work the potential of using the interferometric coherence at different polarisations over surface scat- terers in order to extract information about surface parameters is investigated. For the first time the sensitivity of the indi- vidual coherence contributions to surface roughness and moisture conditions is discussed and simulated using a novel hy- brid polarimetric surface scattering model. The model itself consists of two components, a coherent part obtained from the extended Bragg model and an incoherent part obtained from the integral equation model. Finally, experimental airborne SAR data are used to validate the modeled elements of the Pauli scattering vector.

  7. A Method of Forest Type Classification Using PolInSAR Data

    NASA Astrophysics Data System (ADS)

    Wang, Xinshuang; Chen, Erxue; Li, Zengyuan; Yao, Wangqiang; Li, Wenmei; Li, Xiao

    2013-01-01

    Forest type mapping is of great significance for regional forest carbon estimation as forest types distribution information is always the critical prior input information to forest carbon stock mapping model using remote sensing. Polarimetric interferometric synthetic aperture radar (Pol-InSAR) data acquired by DLR airborne SAR system (ESAR) in the Traunstein test site in Germany was used to study forest type classification method in this paper. A new unsupervised PolInSAR classification method based on coherent optimization R matrix was proposed to distinguish coniferous forest, deciduous forest and other land cover types. It not only considers the full polarimetric information of single Polarimetric SAR (PolSAR) data set but also the coherent information of a pair of PolSAR data. The results show that the classification algorithm proposed in this paper is the best method with higher accuracy comparing with the classical method based on T6 matrix.

  8. Fourth Airborne Geoscience Workshop

    NASA Technical Reports Server (NTRS)

    1991-01-01

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

  9. Software for Generating Strip Maps from SAR Data

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Liu, Zhen; Lundgren, Paul

    2016-07-01

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

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

    SciTech Connect

    Carlisle, R.G.; Davis, M.

    1996-11-01

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

  12. Detection of surface and buried mines with an UHF airborne SAR

    NASA Astrophysics Data System (ADS)

    Grosch, Theodore O.; Lee, Check F.; Adams, Eileen M.; Tran, Chi; Koening, Francois; Tom, Kwok; Vickers, Roger S.

    1995-06-01

    A small minefield was deployed in the desert near Yuma, Arizona in June of 1993. Radar data of this minefield was collected by ground-based and airborne radar sensors. The minefield consists of M-20 metal and M-80 plastic anti-armor mines and Valmara-69 antipersonnel mines. The mines were deployed on the surface and buried at three different depths. Images and analysis of the minefield, which are derived from data collected by the SRI FOLPEN II synthetic aperture radar, are presented here. The minefield was imaged over three bands from 100 to 500 MHz and at various depression angles with this radar sensor. The image analysis is compared to the modeling results of surface and buried mine-like objects. We also show the results of a new radio frequency interference (RFI) rejection algorithm and the image quality improvement we achieved.

  13. Regional reconnaissance of seasonal landslide activity in the Eel River catchment, northern California, using InSAR and airborne LiDAR

    NASA Astrophysics Data System (ADS)

    Handwerger, A. L.; Schmidt, D. A.; Roering, J. J.

    2010-12-01

    Remote sensing techniques have greatly improved our ability to quantify deformation of the Earth’s surface and provide reconnaissance information with high temporal and spatial resolution. We use InSAR and airborne LiDAR to examine the spatial and temporal behavior of 15 landslides located in the Eel River catchment, northern California. The Eel River catchment is well known for its large, deep seated, slow-moving landslides. This region is ideal for landslide studies using InSAR because the landslides are continuously moving at a rate fast enough to observe deformation in a short time span, yet slow enough to avoid a loss in radar coherence (Roering et al., 2009). 10 of the 15 landslides presented here have not been previously identified using InSAR and were identified using statistical analysis to discriminate consistent small-scale deformation from artifacts. We produced 30 differential interferograms between February 2007 and May 2010 using ALOS PALSAR data from tracks 223 and 224 with the ROI_PAC processing package. The 15 identified landslides move at line-of sight rates ranging from 0.1 m yr -1 to 0.45 m yr -1, and have dimensions ranging from 0.5 to 5 km long and 0.27 to 3 km wide. To explore seasonal variations in landslide velocity, we construct InSAR time series from the inversion of small-baseline interferograms. Preliminary results show that slide acceleration lags the onset of rainfall events by weeks to months. Combining InSAR and a shaded relief LiDAR image, we identify distinct kinematic zones (e.g. source, transport, toe) within most landslides. This study demonstrates the capabilities of InSAR and airborne LiDAR to explore the spatial and temporal behavior of large, slow-moving landslides in a regional context. Although InSAR analyses of landslides is successful at this field site, there exists a bias toward optimally oriented landslides in our regional reconnaissance. InSAR is blind to surface displacement that is parallel to the satellite

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

    DOEpatents

    Tise, Bertice L.; Dubbert, Dale F.

    2005-03-08

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

  15. Continuous monitoring of biophysical Eucalyptus sp. parameters using interferometric synthetic aperture radar data in P and X bands

    NASA Astrophysics Data System (ADS)

    Gama, Fábio Furlan; dos Santos, João Roberto; Mura, José Claudio

    2016-04-01

    This work aims to verify the applicability of models obtained using interferometric synthetic aperture radar (SAR) data for estimation of biophysical Eucalyptus saligna parameters [diameter of breast height (DBH), total height and volume], as a method of continuous forest inventory. In order to obtain different digital elevation models, and the interferometric height (Hint) to retrieve the tree heights, SAR surveying was carried out by an airborne interferometric SAR in two frequencies X and P bands. The study area, located in the Brazilian southeast region (S 22°53‧22″/W 45°26‧16″ and S 22°53‧22″/W 45°26‧16″), comprises 128.64 hectares of Eucalyptus saligna stands. The methodological procedures encompassed: forest inventory, topographic surveying, radar mapping, radar processing, and multivariable regression techniques to build Eucalyptus volume, DBH, and height models. The statistical regression pointed out Hint and interferometric coherence as the most important variables for the total height and DBH estimation; for the volume model, however, only the Hint variable was selected. The performance of the biophysical models from the second campaign, two years later (2006), were consistent and its results are very promising for updating annual inventories needed for managing Eucalyptus plantations.

  16. The sensitivity of a volcanic flow model to digital elevation model accuracy: experiments with digitised map contours and interferometric SAR at Ruapehu and Taranaki volcanoes, New Zealand

    NASA Astrophysics Data System (ADS)

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

    2003-01-01

    A growing trend in the field of volcanic hazard assessment is the use of computer models of a variety of flows to predict potential areas of devastation. These can be compared against historic and geologic evidence of past events for model calibration, or used to construct hazard zone maps for mitigation and planning purposes. The accuracy of these computer models depends on two factors, the nature and veracity of the flow model itself, and the accuracy of the topographic data set over which it is run. All digital elevation models (DEMs) contain innate errors. The nature of these depends on the accuracy of the original measurements of the terrain, and on the method used to build the DEM. In this paper we investigate the effect that these errors have on the performance of a volcanic flow model designed to delineate areas at risk from lahar inundation. The model was run over two DEMs of southern Ruapehu volcano derived from (1) digitised 1:50 000 topographic maps, and (2) airborne C-band synthetic aperture radar (SAR) interferometry obtained using the NASA AIRSAR system. On steep slopes of ˜4° or more, drainage channels are more likely to be incised deeply, and flow paths predicted by the model are generally in agreement for both DEMs despite the differing nature of the source data. Over shallow slopes (˜<4°), where channels are less deep and are more likely to meander, problems were encountered with flow path prediction in both DEMs due to interpolation errors between contours, and due to forestry. The predicted lateral and longitudinal extent of deposit inundation was also sensitive to the type of DEM used, most likely in response to the differing degrees of surface texture preserved in the DEMs. A technique to refine contour-derived DEMs and reduce the error in predicted flow paths was tested to improve the reliability of the modelled flow path predictions. In areas where high-resolution topographic maps are unavailable, forthcoming topographic measurements

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

    NASA Technical Reports Server (NTRS)

    Blumberg, Dan G.; Greeley, Ronald

    1995-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

  19. Advanced algorithms and high-performance testbed for large-scale site characterization and subsurface target detection using airborne ground-penetrating SAR

    NASA Astrophysics Data System (ADS)

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

    1999-08-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  1. Forest Attributes from Radar Interferometric Structure and its Fusion with Optical Remote Sensing

    NASA Technical Reports Server (NTRS)

    Treuhaft, Robert N.; Law, Beverly E.; Asner, Gregory P.

    2004-01-01

    The possibility of global, three-dimensional remote sensing of forest structure with interferometric synthetic aperture radar (InSAR) bears on important forest ecological processes, particularly the carbon cycle. InSAR supplements two-dimensional remote sensing with information in the vertical dimension. Its strengths in potential for global coverage complement those of lidar (light detecting and ranging), which has the potential for high-accuracy vertical profiles over small areas. InSAR derives its sensitivity to forest vertical structure from the differences in signals received by two, spatially separate radar receivers. Estimation of parameters describing vertical structure requires multiple-polarization, multiple-frequency, or multiple-baseline InSAR. Combining InSAR with complementary remote sensing techniques, such as hyperspectral optical imaging and lidar, can enhance vertical-structure estimates and consequent biophysical quantities of importance to ecologists, such as biomass. Future InSAR experiments will supplement recent airborne and spaceborne demonstrations, and together with inputs from ecologists regarding structure, they will suggest designs for future spaceborne strategies for measuring global vegetation structure.

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  3. Integrated analysis of differential interferometric synthetic aperture radar (DInSAR) and geological data for measuring deformation movement of Kaligarang fault, Semarang-Indonesia

    NASA Astrophysics Data System (ADS)

    Prasetyo, Y.; Fakhrudin, Warasambi, S. M.

    2016-05-01

    Semarang is one of the densely populated city in Central Java which is has Kaligarang's fault. It is lie in Kaligarang River and across several dense urban settlement. The position of Kaligarang's river itself divides in the direction nearly north-south city of Semarang. The impact of the fault can be seen in severals indication such as a land subsidence phenomenon in Tinjomoyo village area which is make impact to house and road destruction. In this research, we have used combination methods between InSAR, DinSAR and geomorphology (geology data) where is this techniques used to identity the fault area and estimate Kaligarang's fault movement velocity. In fault movement velocity observation, we only compute the movement in vertical with neglect horizontal movement. The data used in this study of one pair ALOS PALSAR level 1.0 which was acquired on June 8, 2007and 10 of September 2009. Besides that third ALOS PALSAR earlier, also used data of SRTM DEM 4th version, is used for the correction of the topography. The use of the three methods already mentioned earlier have different functions. For the lnSAR method used for the establishment of a digital model in Semarang. After getting high models digital city of Semarang, the identification process can be done layout, length, width and area of the Kaligarang fault using geomorphology. Results of such identification can be calculated using the rate of deformation and fault movement. From the result generated DinSAR method of land subsidence rate between 3 em to II em. To know the truth measurement that used DinSAR method, is performed with the decline of validation that measured using GPS. After validating obtained standard deviation of 3,073 em. To estimate the Kaligarang's fault pattern and direction is using the geomorphology method. The results that Kaligarang's is an active fault that has fault strike slip as fault pattern. It makes this research is useful because could be used as an inquick assessment in fault

  4. The NASA/JPL Airborne Synthetic Aperture Radar System

    NASA Technical Reports Server (NTRS)

    Lou, Yunling; Kim,Yunjin; vanZyl, Jakob

    1996-01-01

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

  5. Using TerraSAR-X and hyperspectral airborne data to monitor surface deformation and physical properties of the Barrow permafrost landscape, Alask

    NASA Astrophysics Data System (ADS)

    Haghshenas-Haghighi, M.; Motagh, M.; Heim, B.; Sachs, T.; Kohnert, K.; Streletskiy, D. A.

    2014-12-01

    In this study, we assess seasonal subsidence/heaving due to thawing/freezing of the permafrost in Barrow (71.3 N, 156.5 W) at the northernmost point of Alaska. The topographic relief in this area is low. Thick Permafrost underlies the entire area, with large ice volumes in its upper layer. With a large collection of field measurements during the past decades at the Barrow Environmental Observatory (BEO), it is an ideal site for permafrost investigation. There are long term systematic geocryological investigations within the Global Terrestrial Network (GTN-P) of the Circumpolar Active Layer Monitoring (CALM) programme. We use 28 TerraSAR-X images, acquired between December 2012 and December 2013 and analyze them using the Small BAseline Subset (SBAS) technique to extract time-series of ground surface deformation. We also analyze hyperspectral images acquired by the airborne AISA sensor over Barrow area, within the AIRMETH2013 programme, to assess physical characteristics such as vegetation biomass and density, surface moisture, and water bodies. Finally, we combine the information derived from both InSAR and hyperspectral analysis, with field measurements to investigate the link between physical characteristics of the permafrost and surface displacement.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  7. SAR Product Control Software

    NASA Astrophysics Data System (ADS)

    Meadows, P. J.; Hounam, D.; Rye, A. J.; Rosich, B.; Börner, T.; Closa, J.; Schättler, B.; Smith, P. J.; Zink, M.

    2003-03-01

    As SAR instruments and their operating modes become more complex, as new applications place more and more demands on image quality and as our understanding of their imperfections becomes more sophisticated, there is increasing recognition that SAR data quality has to be controlled more completely to keep pace. The SAR product CONtrol software (SARCON) is a comprehensive SAR product control software suite tailored to the latest generation of SAR sensors. SARCON profits from the most up-to-date thinking on SAR image performance derived from other spaceborne and airborne SAR projects and is based on the newest applications. This paper gives an overview of the structure and the features of this new software tool, which is a product of a co-operation between teams at BAE SYSTEMS Advanced Technology Centre and DLR under contract to ESA (ESRIN). Work on SARCON began in 1999 and is continuing.

  8. Recent Advances in Radar Polarimetry and Polarimetric SAR Interferometry

    NASA Technical Reports Server (NTRS)

    Boerner, Wolfgang-Martin

    2005-01-01

    The development of Radar Polarimetry and Radar Interferometry is advancing rapidly, and these novel radar technologies are revamping Synthetic Aperture Radar Imaging decisively. In this exposition the successive advancements are sketched; beginning with the fundamental formulations and high-lighting the salient points of these diverse remote sensing techniques. Whereas with radar polarimetry the textural fine-structure, target-orientation and shape, symmetries and material constituents can be recovered with considerable improvements above that of standard amplitude-only Polarization Radar ; with radar interferometry the spatial (in depth) structure can be explored. In Polarimetric-Interferometric Synthetic Aperture Radar (POL-IN-SAR) Imaging it is possible to recover such co-registered textural plus spatial properties simultaneously. This includes the extraction of Digital Elevation Maps (DEM) from either fully Polarimetric (scattering matrix) or Interferometric (dual antenna) SAR image data takes with the additional benefit of obtaining co-registered three-dimensional POL-IN-DEM information. Extra-Wide-Band POL-IN-SAR Imaging - when applied to Repeat-Pass Image Overlay Interferometry - provides differential background validation and measurement, stress assessment, and environmental stress-change monitoring capabilities with hitherto unattained accuracy, which are essential tools for improved global biomass estimation. More recently, by applying multiple parallel repeat-pass EWB-POL-D(RP)-IN-SAR imaging along stacked (altitudinal) or displaced (horizontal) flight-lines will result in Tomographic (Multi- Interferometric) Polarimetric SAR Stereo-Imaging , including foliage and ground penetrating capabilities. It is shown that the accelerated advancement of these modern EWB-POL-D(RP)-IN-SAR imaging techniques is of direct relevance and of paramount priority to wide-area dynamic homeland security surveillance and local-to-global environmental ground-truth measurement

  9. Temporal multiparameter airborne DLR E-SAR images for crop monitoring: summary of the CLEOPATRA campaign 1992

    NASA Astrophysics Data System (ADS)

    Schmullius, Christiane C.; Nithack, Juergen

    1997-01-01

    From May 11 to July 31, 1992 the Cloud Experiment OberPfaffenhofen And Transports took place as a field experimental contribution to the global energy and water cycle experiment. The DLR Institute of Radio Frequency Technology participated with its experimental SAR system E- SAR. Multitemporal X-, C- and L-band data from 8 dates and three ERS-1 images between May 20 and July 30, 1992 are analyzed in regard to the influence of changing plant backscatter constituents and to investigate the impact of increasing ground cover in the different wavelength on soil moisture mapping. Backscatter curves of four crops are shown, which indicate the possibility for crop monitoring and preferred times for crop classification. Detection of soil moisture changes is only possible with L-band and only under grain crops. Maximum likelihood and isocluster classifications were applied on several single- and multifrequency, mono- and multitemporal channel combinations. The overall classification accuracies were higher than with supervised methods. Maximum likelihood classification allowed identification of ten crop types with accuracies of up to 84 percent, when a temporal multifrequency data set was used.

  10. A new method to extract forest height from repeat-pass polarimetric and interferometric radar data

    NASA Astrophysics Data System (ADS)

    Lavalle, M.; Hensley, S.; Dubayah, R.

    2012-12-01

    The objective of this paper is to present a new remote sensing method and a new physical model that will potentially enable estimating forest height and vegetation 3D structure using radar technology. The method is based on repeat-pass polarimetric-interferometric radar technique; the model is termed random-motion-over-ground (RMoG) model [1, 2]. We will describe a step-by-step procedure that will help the ecosystem community to monitor ecosystems at regional and global scale using radar data available from the forthcoming radar missions. We will show first results of forest height estimated from UAVSAR data and compared against LVIS data. We will quantify the error associated to our method. We will also discuss the improvements that we plan on including in future works. Our ultimate goal is to measure low and large biomass stocks using the large amount of radar data that will be available in the near future. The Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) is a fully polarimetric L-band airborne radar developed at the Jet Propulsion Laboratory (JPL). UAVSAR acquires repeat-pass interferometric data for measuring vegetation structure and monitoring crustal deformations. The UAVSAR team at JPL has acquired and processed several polarimetric-interferometric (Pol-InSAR) datasets over the Harvard Forest in Massachusetts (United States) that allows testing repeat-pass Pol-InSAR technique. Pol-InSAR technique was proposed 15 years ago to estimate vegetation biomass and overcome the inherent saturation of radar backscatter versus biomass [3]. The advantage of Pol-InSAR is the ability to estimate the 3D structure of vegetation using a small number of interferometric acquisitions. In order to extract vegetation properties from Pol-InSAR UAVSAR data, we use a model of temporal-volumetric coherence, the RMoG model, suitable for repeat-pass interferometry. In the RMoG model the vegetation is idealized as a two-layer scattering scenario constituted by a

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

    NASA Technical Reports Server (NTRS)

    Paris, J. F.

    1985-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Mleczko, M.

    2014-12-01

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

  13. 3D SAR approach to IF SAR processing

    NASA Astrophysics Data System (ADS)

    Doerry, Armin W.; Bickel, Doug

    2000-08-01

    Interferometric SAR (IFSAR) can be shown to be a special case of 3-D SAR image formation. In fact, traditional IFSAR processing results in the equivalent of merely a super- resolved, under-sampled, 3-D SAR image. However, when approached as a 3-D SAR problem, a number of IFSAR properties and anomalies are easily explained. For example, IFSAR decorrelation with height is merely ordinary migration in 3-D SAR. Consequently, treating IFSAR as a 3-D SAR problem allows insight and development of proper motion compensation techniques and image formation operations to facilitate optimal height estimation. Furthermore, multiple antenna phase centers and baselines are easily incorporated into this formulation, providing essentially a sparse array in the elevation dimension. This paper shows the Polar Format image formation algorithm extended to 3 dimensions, and then proceeds to apply it to the IFSAR collection geometry. This suggests a more optimal reordering of the traditional IFSAR processing steps.

  14. Pseudo-thermal bar in poorly salted autumnal waters of the Gulf of Finland from satellite-airborne SAR/ASAR/ALSAR survey

    NASA Astrophysics Data System (ADS)

    Melentyev, Vladimir; Bobylev, Leonid; Tsepelev, Valery; Melentyev, Konstantin; Bednov, Petr

    2010-05-01

    The thermal bar (TB) was disclosed at the end of XIX century by F.A. Forel - world-famed founder of limnology, who studied different processes in Lake Leman from point of view ecology and hydrobiology. Forel supposed that TB arises in temperate large lakes for short period in spring in presence windless calm weather. Well-directed investigations of TB were recommenced in the beginning 1950-s at the Institute of Lake Research Russian Academy of Sciences by Dr A.I. Tikhomirov who had described also specific features of this phenomenon in fall. At the end of 1960-s we began examination thermal and ice regime of fresh and saltish inland water bodies with using remote sensing including multi-spectral airborne-satellite SLR/SAR/ASAR/ALSAR survey. And as result the possibility revealing TB parameters in fall season by low-frequency radar (ALSAR) installed onboard research aircraft was fixed documentally in the Lake Ladoga [Melentyev et. al., 2002]. According to [Tikhomirov, 1959] TB represents convergence zone around temperature of maximum density of fresh water + 4 °C (3, 98 °C, really). This narrow vertical "curtain" appears in littoral in spring owing to heating coastal waters, in fall - due to its cooling. TB divides large lakes and artificial reservoirs on two unequal thermic zones - heat-active (HAZ) and heat-inert (HIZ) that has different stratification of water temperature. Possible existence of TB in poorly salted sea waters was predicted by outstanding Russian oceanographer professor N. Zubov. Obviously firstly it was disclosed but without explanation the physics by [Bychkova, 1987]. Our own sub-satellite studies onboard nuclear icebreaker "Jamal" in western Arctic in fall 1996 allows reveal the TB on saltish waters in north-eastern "corner" of the Yenisei Gulf in mixing zone of marine and river waters. Long-lived converged zone that we call as pseudo-thermal bar (PTB) was marked by stationary banding narrow continuous rough strip that could be destroyed by

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

    NASA Astrophysics Data System (ADS)

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

    2001-12-01

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

  16. Full-resolution interferometric SAR processing

    NASA Astrophysics Data System (ADS)

    Rogers, George W.; Breitenstein, Darryl S.; Roth, Duane; Mansfield, Arthur W.; Rais, Houra

    2000-08-01

    In this paper we present our approach to full resolution IFSAR processing that retains full azimuth and range resolution for a significant fraction of the pixels. This is accomplished through the use of statistical analysis and nonlinear smoothing in conjunction with limited spectral extrapolation. In our approach, a significant fraction of the pixels retain their original phase values all of the way through the processing. At the same time, we are able to reduce the number of residues by several orders of magnitude. An additional benefit of this approach is the ability to detect and discriminate between complete decorrelation due to large bodies of water and partial decorrelation due to foliage. The approach will be presented along with examples based on ERS tandem pair data.

  17. Interferometric radar imaging using the AN/APG-76 radar

    NASA Astrophysics Data System (ADS)

    O'Brien, James D.; Holt, Hugh D., Jr.; Maney, Harold D., Jr.; Orwig, Lawrence P.

    1996-06-01

    This paper describes recent performance-enhancing modifications made to the AN/APG-76 radar. An interferometric radar equipped with a four-channel receiver and a seven-channel interferometric antenna, the AN/APG-76 has been used to demonstrate novel interferometric imaging concepts. Originally built as a tactical radar with air-to- air modes, SAR, and three-channel DPCA-like MTI modes, the modified radar's capabilities include: real-time autofocused imaging at 3- and 1-foot resolutions, elevation interferometric SAR (both single and repeat pass), polarimetric imaging, precision tracking by means of a tightly-coupled GPS-aided INS system, and moving target imaging using the inherent clutter-cancellation capabilities of the radar. The re-programmability of the on-board processor allows new real-time modes to be implemented, and high-speed data recording allows off-line analysis of data.

  18. Tropical Forest Biomass Estimation from Vertical Fourier Transforms of Lidar and InSAR Profiles

    NASA Astrophysics Data System (ADS)

    Treuhaft, R. N.; Goncalves, F.; Drake, J.; Hensley, S.; Chapman, B. D.; Michel, T.; Dos Santos, J. R.; Dutra, L.; Graca, P. A.

    2010-12-01

    Structural forest biomass estimation from lidar or interferometric SAR (InSAR) has demonstrated better performance than radar-power-based approaches for the higher biomasses (>150 Mg/ha) found in tropical forests. Structural biomass estimation frequently regresses field biomass to some function of forest height. With airborne, 25-m footprint lidar data and fixed-baseline C-band InSAR data over tropical wet forests of La Selva Biological Station, Costa Rica, we compare the use of Fourier transforms of vertical profiles at a few frequencies to the intrinsically low-frequency “average height”. RMS scatters of Fourier-estimated biomass about field-measured biomass improved by 40% and 20% over estimates base on average height from lidar and fixed-baseline InSAR, respectively. Vertical wavelengths between 14 and 100 m were found to best estimate biomass. The same airborne data acquisition over La Selva was used to generate many 10’s of repeat-track L-band InSAR baselines with time delays of 1-72 hours, and vertical wavelengths of 5-100 m. We will estimate biomass from the Fourier transforms of L-band radar power profiles (InSAR complex coherence). The effects of temporal decorrelation will be modeled in the Fourier domain to try to model and reduce their impact. Using L-band polarimetric interferometry, average heights will be estimated as well and biomass regression performance compared to the Fourier transform approach. The more traditional approach of using L-band radar polarimetry will also be compared to structural biomass estimation.

  19. SAR imaging via modern 2-D spectral estimation methods.

    PubMed

    DeGraaf, S R

    1998-01-01

    This paper discusses the use of modern 2D spectral estimation algorithms for synthetic aperture radar (SAR) imaging. The motivation for applying power spectrum estimation methods to SAR imaging is to improve resolution, remove sidelobe artifacts, and reduce speckle compared to what is possible with conventional Fourier transform SAR imaging techniques. This paper makes two principal contributions to the field of adaptive SAR imaging. First, it is a comprehensive comparison of 2D spectral estimation methods for SAR imaging. It provides a synopsis of the algorithms available, discusses their relative merits for SAR imaging, and illustrates their performance on simulated and collected SAR imagery. Some of the algorithms presented or their derivations are new, as are some of the insights into or analyses of the algorithms. Second, this work develops multichannel variants of four related algorithms, minimum variance method (MVM), reduced-rank MVM (RRMVM), adaptive sidelobe reduction (ASR) and space variant apodization (SVA) to estimate both reflectivity intensity and interferometric height from polarimetric displaced-aperture interferometric data. All of these interferometric variants are new. In the interferometric contest, adaptive spectral estimation can improve the height estimates through a combination of adaptive nulling and averaging. Examples illustrate that MVM, ASR, and SVA offer significant advantages over Fourier methods for estimating both scattering intensity and interferometric height, and allow empirical comparison of the accuracies of Fourier, MVM, ASR, and SVA interferometric height estimates.

  20. A methodology for outperforming filtering results in the interferometric process

    NASA Astrophysics Data System (ADS)

    Saqellari-Likoka, A.; Karathanassi, V.

    2015-10-01

    In this study, a method for reducing the filtering effects on the interferometric phase signal is proposed. Theoretical analysis showed that while noise reduction is maximized after filtering, the loose of interferometric phase signal is also maximized. This state has been also verified by observations on SAR interferometric data where pixels with high coherence value, which are assumed to contain a lot of information, presented lower coherence values after SAR image filtering. The proposed method performs interferometric phase modeling. The method recovers the signal after the interferometric filtering for the pixels that loss of information is observed. The selection of these pixels is based on the decrease of their coherence value after the filtering. Signal recovery is associated to the preservation of the initial values for these pixels. Consequently, the method prevents the decrease of the coherence values for these pixels. Performance of the method depends on the performance of the used filter; however, it always improves the interferometric results. Since the phase signal is the basis for the DEM production, its preservation improves all the steps of the interferometric procedure, especially the phase unwapping. Effects of the method on the final interferometric product, the DEM, are also evident. The proposed method was evaluated using real interferometric data. Experiments showed that the applied filters within this study, did not always improve the accuracy of the produced DEM. Sub-images for which filtering does not improve their mean coherence value have been selected and the proposed method has been applied. For these sub-images, coherence values and RMS errors of the produced DEMs showed that the method improves the results of the interferometric procedure. It compensates the negative effects of the filtering for these sub-images and leads to the improvement of the DEM accuracy in the majority of the cases.

  1. (abstract) Studies of Interferometric Penetration into Vegetation Canopies using Multifrequency Interferometry Data at JPL

    NASA Technical Reports Server (NTRS)

    Hensley, Scott; Rodriguez, Ernesto; Truhafft, Bob; van Zyl, Jakob; Rosen, Paul; Werner, Charles; Madsen, Sren; Chapin, Elaine

    1997-01-01

    Radar interferometric observations both from spaceborne and airborne platforms have been used to generate accurate topographic maps, measure milimeter level displacements from earthquakes and volcanoes, and for making land cover classification and land cover change maps. Interferometric observations have two basic measurements, interferometric phase, which depends upon the path difference between the two antennas and the correlation. One of the key questions concerning interferometric observations of vegetated regions is where in the canopy does the interferometric phase measure the height. Results for two methods of extracting tree heights and other vegetation parameters based upon the amount of volumetric decorrelation will be presented.

  2. The NASA/JPL Airborne Synthetic Aperture Radar System

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  3. ARBRES: light-weight CW/FM SAR sensors for small UAVs.

    PubMed

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

    2013-01-01

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

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

    SciTech Connect

    Vincent, P; Rodgers, A; Dodge, D; Zucca, J; Schultz, C; Walter, B; Portnoff, M

    2003-02-07

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

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

    PubMed Central

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

    2013-01-01

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

  6. Interferometric synthetic aperture radar studies of Alaska volcanoes

    USGS Publications Warehouse

    Lu, Zhiming; Wicks, C.; Power, J.; Dzurisin, D.; Thatcher, W.; Masterlark, Timothy

    2002-01-01

    Interferometric synthetic aperture radar (InSAR) imaging is a recently developed geodetic technique capable of measuring ground-surface deformation with centimeter to subcentimeter vertical precision and spatial resolution of tens-of-meter over a relatively large region (~104 km2). The spatial distribution of surface deformation data, derived from InSAR images, enables the construction of detailed mechanical models to enhance the study of magmatic and tectonic processes associated with volcanoes. This paper summarizes our recent InSAR studies of several Alaska volcanoes, which include Okmok, Akutan, Kiska, Augustine, Westdahl, and Peulik volcanoes.

  7. Gulf Coast Subsidence: Integration of Geodesy, Geophysical Modeling, and Interferometric Synthetic Aperture Radar Observations

    NASA Astrophysics Data System (ADS)

    Blom, R. G.; Chapman, B. D.; Deese, R.; Dokka, R. K.; Fielding, E. J.; Hawkins, B.; Hensley, S.; Ivins, E. R.; Jones, C. E.; Kent, J. D.; Liu, Z.; Lohman, R.; Zheng, Y.

    2012-12-01

    The vulnerability of the US Gulf Coast has received increased attention in the years since hurricanes Katrina and Rita. Agencies responsible for the long-term protection of lives and infrastructure require precise estimates of future subsidence and sea level rise. A quantitative, geophysically based methodology can provide such estimates by incorporating geological data, geodetic measurements, geophysical models of non-elastic mechanical behavior at depth, and geographically comprehensive deformation monitoring made possible with measurements from Interferometric Synthetic Aperture Radar (InSAR). To be effective, results must be available to user agencies in a format suitable for integration within existing decision-support processes. Work to date has included analysis of historical and continuing ground-based geodetic measurements. These reveal a surprising degree of complexity, including regions that are subsiding at rates faster than those considered for hurricane protection planning of New Orleans and other coastal communities (http://www.mvn.usace.army.mil/pdf/hps_verticalsettlement.pdf) as well as Louisiana's coastal restoration strategies (http://www.coast2050.gov/2050reports.htm) (Dokka, 2011, J. Geophys. Res., 116, B06403, doi:10.1029/2010JB008008). Traditional geodetic measurements provide precise information at single points, while InSAR observations provide geographically comprehensive measurements of surface deformation at lower vertical precision. Available InSAR data sources include X-, C- and L-band satellite, and NASA/JPL airborne UAVSAR L-band data. The Gulf Coast environment is very challenging for InSAR techniques, especially with systems not designed for interferometry. For example, the shorter wavelength C-band data decorrelates over short time periods requiring more elaborate time-series analysis techniques, with which we've had some success. Meanwhile, preliminary analysis of limited L-Band ALOS/PALSAR satellite data show promise

  8. Interferometric synthetic aperture radar: building tomorrow's tools today

    USGS Publications Warehouse

    Lu, Zhong

    2006-01-01

    A synthetic aperture radar (SAR) system transmits electromagnetic (EM) waves at a wavelength that can range from a few millimeters to tens of centimeters. The radar wave propagates through the atmosphere and interacts with the Earth’s surface. Part of the energy is reflected back to the SAR system and recorded. Using a sophisticated image processing technique, called SAR processing (Curlander and McDonough, 1991), both the intensity and phase of the reflected (or backscattered) signal of each ground resolution element (a few meters to tens of meters) can be calculated in the form of a complex-valued SAR image representing the reflectivity of the ground surface. The amplitude or intensity of the SAR image is determined primarily by terrain slope, surface roughness, and dielectric constants, whereas the phase of the SAR image is determined primarily by the distance between the satellite antenna and the ground targets, slowing of the signal by the atmosphere, and the interaction of EM waves with ground surface. Interferometric SAR (InSAR) imaging, a recently developed remote sensing technique, utilizes the interaction of EM waves, referred to as interference, to measure precise distances. Very simply, InSAR involves the use of two or more SAR images of the same area to extract landscape topography and its deformation patterns.

  9. SARS: hospital infection control and admission strategies.

    PubMed

    Ho, Pak-Leung; Tang, Xiao-Ping; Seto, Wing-Hong

    2003-11-01

    Nosocomial clustering with transmission to health care workers, patients and visitors is a prominent feature of severe acute respiratory syndrome (SARS). Hospital outbreaks of SARS typically occurred within the first week after admission of the very first SARS cases when the disease was not recognized and before isolation measures were implemented. In the majority of nosocomial infections, there was a history of close contact with a SARS patient, and transmission occurred via large droplets, direct contact with infectious material or by contact with fomites contaminated by infectious material. In a few instances, potential airborne transmission was reported in association with endotracheal intubation, nebulised medications and non-invasive positive pressure ventilation of SARS patients. In all SARS-affected countries, nosocomial transmission of the disease was effectively halted by enforcement of routine standard, contact and droplet precautions in all clinical areas and additional airborne precautions in the high-risk areas. In Hong Kong, where there are few private rooms for patient isolation, some hospitals have obtained good outcome by having designated SARS teams and separate wards for patient triage, confirmed SARS cases and step-down of patients in whom SARS had been ruled out. In conclusion, SARS represents one of the new challenges for those who are involved in hospital infection control. As SARS might re-emerge, all hospitals should take advantage of the current SARS-free interval to review their infection control programmes, alert mechanisms, response capability and to repair any identified inadequacies.

  10. Reduction of mine suspected areas by multisensor airborne measurements: first results

    NASA Astrophysics Data System (ADS)

    Keller, Martin; Milisavljevic, Nada; Suess, Helmut; Acheroy, Marc P. J.

    2002-08-01

    Humanitarian demining is a very dangerous, cost and time intensive work, where a lot of effort is usually wasted in inspecting suspected areas that turn out to be mine-free. The main goal of the project SMART (Space and airborne Mined Area Reduction Tools) is to apply a multisensor approach towards corresponding signature data collection, developing adapted data understanding and data processing tools for improving the efficiency and reliability of level 1 minefield surveys by reducing suspected mined areas. As a result, the time for releasing mine-free areas for civilian use should be shortened. In this paper, multisensor signature data collected at four mine suspected areas in different parts of Croatia are presented, their information content is discussed, and first results are described. The multisensor system consists of a multifrequency multipolarization SAR system (DLR Experimental Synthetic Aperture Radar E-SAR), an optical scanner (Daedalus) and a camera (RMK) for color infrared aerial views. E-SAR data were acquired in X-, C-, L- and P- bands, the latter two being fully polarimetric interferometric. This provides pieces of independent information, ranging from high spatial resolution (X-band) to very good penetration abilities (P-band), together with possibilities for polarimetric and interferometric analysis. The Daedalus scanner, with 12 channels between visible and thermal infrared, has a very high spatial resolution. For each of the sensors, the applied processing, geocoding and registration is described. The information content is analyzed in sense of the capability and reliability in describing conditions inside suspected mined areas, as a first step towards identifying their mine-free parts, with special emphasis set on polarimetric and interferometric information.

  11. Chirp Scaling Algorithms for SAR Processing

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  12. InSAR Scientific Computing Environment

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  13. Multibaseline POLInSAR Module for SAR Data Processing and Analysis in RAT (Radar Tools)

    NASA Astrophysics Data System (ADS)

    Neumann, M.; Reiber, A.; Jäger, M.; Guillaso, S.; Hellwich, O.

    2007-03-01

    The combination of SAR Polarimetry (POL- SAR) and SAR Interferometry (InSAR) into Polarimetric SAR Interferometry (POLInSAR) has shown great potential for information extraction from SAR data. Applications have been developed and validated theoretically for POLInSAR data. But due to different reasons these methods are difficult to apply on real data. The SAR observables have to be increased, and the utilization of multiple baselines (MB) is one of the possibilities. There will be a need for data processing and analysis methods and tools to work effectively with multibaseline datasets. In this paper we present the newly developed module for the software package RAT (Radar Tools), which provides these abilities for multibaseline polarimetric interferometric SAR data. It is the first available package of tools for working with MBSAR data. RAT (RAdar Tools [1], [2]) is a collection of tools for advanced image processing of SAR remote sensing data, originally started as a student's project and currently under further development at the Department of Computer Vision and Remote Sensing of the Technical University of Berlin. It is programmed in IDL (Interactive Data Language) and uses IDL widgets as graphical user interface. The purpose of this paper is also to give an overview of the current development status of RAT through addressing the newest structural improvements in RAT as well as recently implemented methods for SAR polarimetry and interferometry.

  14. Application of Polarimetric-Interferometric Phase Coherence Optimization (PIPCO) Procedure to SIR-C/X-SAR Tien-Shan Tracks 122.20(94 Oct. 08)/154.20(94 Oct. 09) Repeat-Orbit C/L-Band Pol-D-InSAR Imag

    NASA Technical Reports Server (NTRS)

    Boerner, W. M.; Mott, H.; Verdi, J.; Darizhapov, D.; Dorjiev, B.; Tsybjito, T.; Korsunov, V.; Tatchkov, G.; Bashkuyev, Y.; Cloude, S.; Papathanassiou, K.; Pottier, E.; Lee, J.; Ainsworth, T.; Schuler, D.; Grandi, G.; Rosen, P.; Peltzer, G.

    1998-01-01

    During the past decade, Radar Polarimetry has established itself as a mature science and advanced technology in high resolution POL-SAR imaging, image target characterization and selective image feature extraction.

  15. Damage Assessment Map from Interferometric Coherence

    NASA Astrophysics Data System (ADS)

    Yun, S.; Fielding, E. J.; Simons, M.; Rosen, P. A.; Owen, S. E.; Webb, F.

    2010-12-01

    Large earthquakes cause buildings to collapse, which often claims the lives of many. For example, 2010 Haiti earthquake killed about 230,000 people, with about 280,000 buildings collapsed or severely damaged. When a major earthquake hits an urban area, one of the most critical information for rescue operations is rapid and accurate assessment of building-collapse areas. From a study on 2003 Bam earthquake in Iran, interferometric coherence was proved useful for earthquake damage assessment (Fielding et al., 2005) when similar perpendicular baselines can be found for pre- and coseismic interferometric pairs and when there is little temporal and volume decorrelation. In this study we develop a new algorithm to create a more robust and accurate damage assessment map using interferometric coherence despite different interferometric baselines and with other decorrelation sources. We test the algorithm on a building block that recently underwent demolition, which is a proxy for building collapse due to earthquakes, for new construction in the City of Pasadena, California. The size of the building block is about 150 m E-W and 300 m N-S, and the demolition project started on April 23, 2007 and continued until January 22, 2008. After we process Japanese L-band ALOS PALSAR data with ROI_PAC, an interferometric coherence map that spans the demolition period is registered to a coherence map before the demolition, and the relative bias of the coherence values are removed, then a causality constraint is applied to enhance the change due to demolition. The results show clear change in coherence at the demolition site. We improve the signal-to-noise ratio of the coherence change at the demolition site from 17.3 (for simple difference) to 44.6 (with the new algorithm). The damage assessment map algorithm will become more useful with the emergence of InSAR missions with more frequent data acquisition, such as Sentinel-1 and DESDynI.

  16. NASA/JPL Aircraft SAR Workshop Proceedings

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  17. Interferometric phase reconstruction using simplified coherence network

    NASA Astrophysics Data System (ADS)

    Zhang, Kui; Song, Ruiqing; Wang, Hui; Wu, Di; Wang, Hua

    2016-09-01

    Interferometric time-series analysis techniques, which extend the traditional differential radar interferometry, have demonstrated a strong capability for monitoring ground surface displacement. Such techniques are able to obtain the temporal evolution of ground deformation within millimeter accuracy by using a stack of synthetic aperture radar (SAR) images. In order to minimize decorrelation between stacked SAR images, the phase reconstruction technique has been developed recently. The main idea of this technique is to reform phase observations along a SAR stack by taking advantage of a maximum likelihood estimator which is defined on the coherence matrix estimated from each target. However, the phase value of a coherence matrix element might be considerably biased when its corresponding coherence is low. In this case, it will turn to an outlying sample affecting the corresponding phase reconstruction process. In order to avoid this problem, a new approach is developed in this paper. This approach considers a coherence matrix element to be an arc in a network. A so-called simplified coherence network (SCN) is constructed to decrease the negative impact of outlying samples. Moreover, a pointed iterative strategy is designed to resolve the transformed phase reconstruction problem defined on a SCN. For validation purposes, the proposed method is applied to 29 real SAR images. The results demonstrate that the proposed method has an excellent computational efficiency and could obtain more reliable phase reconstruction solutions compared to the traditional method using phase triangulation algorithm.

  18. Pol(In)SAR Soil Moisture Study by using Pi-SAR 2L and GB-SAR Data in Preparation of the upcoming ALOS-2/PALSAR-2 Mission

    NASA Astrophysics Data System (ADS)

    Koyama, C.; Sato, M.

    2013-12-01

    Recently Earth Observation by means of active microwave is advancing rapidly. The evolution started from first-generation classical single-channel systems like JERS (JAXA), ERS (ESA) or Radarsat-1 (CSA). With the launch of ALOS-1 (JAXA), the first fully polarimetric SAR measurements became available followed by Radarsat-2 (CSA) and TerraSAR-X (DLR), making polarimetric L-, C-, and X-band data available. In Japanese fiscal year 2013, the third generation of SAR satellites will begin with the launch of ALOS-2. The JAXA cutting-edge follow-on mission to the highly acclaimed ALOS-1 will carry the state-of-the-art PALSAR-2 sensor aboard. Due to its much better orbital revisit cycle of only 14 days and its very high spatial resolution (3 m) the system will be highly suitable for interferometric analysis of polarimetric data obtained from repeat-pass acquisitions. The combination of polarimetry and interferometry is probably the most promising approach for a better estimation of geophysical parameters from SAR data acquired over natural terrain and thus will greatly improve the capabilities to estimate soil moisture under all kinds of vegetation with high accuracy and with high temporal and spatial resolutions. In advent of the 3rd generation of Japanese SAR EO satellites, our group conducts a variety of fundamental research on low-frequency SAR surface scattering/interactions. Here, we present first results from soil moisture experiments based on fully polarimetric GB-SAR (Tohoku University) and Pi-SAR 2L (JAXA) measurements. These experiments comprise investigations of the effective soil moisture measuring depth of L-band SAR. The experimental set-up consists of an array of receiving di-pole antennas installed in different depths to quantify the penetration (and reflection) capabilities of the incoming EM waves. We use a fully polarimetric GB-SAR system based on a high-end VNA capable of coherent measurement of the [S2] scattering matrix. It uses 2 large horn antennas

  19. Repeat-pass InSAR processing for Vegetation Height Calculation: Theory and a validated example

    NASA Astrophysics Data System (ADS)

    Siqueira, P.; Lei, Y.

    2014-12-01

    Knowledge of the vegetation height for a forested region is often used as a proxy for stem volume, biomass, and for characterizing habitats of a variety of plant and animal species. For this reason, remote sensing measures available from stereography, lidar, and InSAR have been important tools for airborne and spaceborne platforms. Among these and other candidates for measuring vegetation heights, InSAR has the advantage of achieving wide coverage areas (on the order of 100 km in cross-track swath) over short time periods, thus making it practical for large-scale assessments of the global environment. The determination of forest stand height (FSH), which is an assessment made on the order of one to ten hectares of resolution, InSAR can provide measures that are proportional to FSH. These are: 1.) interferometric phase compared to a known DEM, preferably of the bald earth, 2.) interferometric correlation (polarimetric or otherwise), which is related to the volume scattering nature of the target, and 3.) interferometric correlation which is related to the temporal decorrelation of the target. Of these, while the volumetric aspect of interferometric correlation is of keen interest, because of the dominant error source of temporal decorrelation, it comes at the cost of the need to perform single-pass interferometry. While such satellite systems do exist (notably the TanDEM-X mission), for vegetation applications, lower frequency systems such as ALOS-1 and -2, and the future NASA radar mission at L-band, provides better signal returns from throughout the vegetation canopy. Hence, rather than relying on volumetric correlation to provide the desired FSH signature, repeat-pass observations of temporal decorrelation are coupled with a vegetation model for this decorrelation to determine the vegetation height. In order to demonstrate this technique, the University of Massachusetts has used 46-day repeat-pass ALOS data to estimate FSH over the US State of Maine, nearly a 10

  20. Independent component analysis for improving the quality of interferometric products

    NASA Astrophysics Data System (ADS)

    Saqellari Likoka, A.; Vafeiadi-Bila, E.; Karathanassi, V.

    2016-05-01

    The accuracy of InSAR DEMs is affected by the temporal decorrelation of SAR images which is due to atmosphere, land use/cover, soil moisture, and roughness changes. Elimination of the temporal decorrelation of the master and slave image improves the DEMs accuracy. In this study, the Independent Component Analysis was applied before interferometric process. It was observed that using three ICA entries, ICA independent sources can be interpreted as background and changed images. ICA when performed on the master and slave images using the same couple of additional images produces two background images which enable the production of high quality DEMs. However, limitations exist in the proposed approach.

  1. Theory and design of interferometric synthetic aperture radars

    NASA Technical Reports Server (NTRS)

    Rodriguez, E.; Martin, J. M.

    1992-01-01

    A derivation of the signal statistics, an optimal estimator of the interferometric phase, and the expression necessary to calculate the height-error budget are presented. These expressions are used to derive methods of optimizing the parameters of the interferometric synthetic aperture radar system (InSAR), and are then employed in a specific design example for a system to perform high-resolution global topographic mapping with a one-year mission lifetime, subject to current technological constraints. A Monte Carlo simulation of this InSAR system is performed to evaluate its performance for realistic topography. The results indicate that this system has the potential to satisfy the stringent accuracy and resolution requirements for geophysical use of global topographic data.

  2. Crustal Deformation Measurements Using Repeat-pass JERS 1 SAR Interferometry Near the Izu Peninsula, Japan

    NASA Technical Reports Server (NTRS)

    Fujiwara, Satoshi; Rosen, Paul A.; Tobita, Mikio; Murakami, Makoto

    1997-01-01

    We have examined the precision of interferometric SAR measurements of surface deformation of the Earth using 24-cm wavelength data acqured by the Japanese Earth Resources Satellite 1 (JERS 1) spacecraft, over the Izu Peninsula, Japan.

  3. Effect of Medium Symmetries on Limiting the Number of Parameters Estimated with Polarimetric SAR Interferometry

    NASA Technical Reports Server (NTRS)

    Moghaddam, M.

    1999-01-01

    The addition of interferometric backscattering pairs to the conventional polarimetric synthetic aperture radar (SAR) data over forests and other vegetated areas increases the dimensionality of the data space, in principle enabling the estimation of a larger number of parameters.

  4. TE/TM Simulations of Interferometric Measurements

    NASA Technical Reports Server (NTRS)

    Houshmand, Bijan

    2000-01-01

    Interferometric synthetic aperture radar (IFSAR) measurements at X-, C-, L-, and P-band are used to derive ground topography at meter level resolution. Interpretation of the derived topography requires attention due to the complex interaction of the radar signal with ground cover. The presence of penetrable surfaces such as vegetation, and tree canopies poses a challenge since the depth of penetration depends on a number of parameters such as the operating radar frequency, polarization, incident angle, as well as terrain structure. The dependence of the reconstructed topography on polarization may lead to the characterization of the ground cover. Simulation of interferometric measurements is useful for interpretation of the derived topography (B. Houshmand, Proceedings of URSI, 314, 1997). In this talk , time domain simulations for interferometric measurement for TE- and TM- polarization are presented. Time domain simulation includes the effects of the surface material property as well geometry comparable the radar signal wavelength (B. Houshmand, Proceedings of the URSI, 25, 1998). The IFSAR simulation is carried out in two steps. First, the forward scattering data is generated based on full wave analysis. Next, the electromagnetic information is inverted to generate surface topography. This inversion is based on the well known IFSAR processing technique which is composed of signal compression, and formation of an interferogram. The full wave forward scattering data is generated by the scattered-field formulation of the FDTD algorithm. The simulation is carried out by exciting the computational domain by a radar signal. The scattered field is then computed and translated to the receiving interferometric antennas using the time-domain Huygen's principle. The inversion process starts by compressing the time-domain data. The range compressed data from both receivers are then coregistered to form an interferogram. The resulting interferogram is then related to the

  5. Similarity measures of full polarimetric SAR images fusion for improved SAR image matching

    NASA Astrophysics Data System (ADS)

    Ding, H.

    2015-06-01

    China's first airborne SAR mapping system (CASMSAR) developed by Chinese Academy of Surveying and Mapping can acquire high-resolution and full polarimetric (HH, HV, VH and VV) Synthetic aperture radar (SAR) data. It has the ability to acquire X-band full polarimetric SAR data at a resolution of 0.5m. However, the existence of speckles which is inherent in SAR imagery affects visual interpretation and image processing badly, and challenges the assumption that conjugate points appear similar to each other in matching processing. In addition, researches show that speckles are multiplicative speckles, and most similarity measures of SAR image matching are sensitive to them. Thus, matching outcomes of SAR images acquired by most similarity measures are not reliable and with bad accuracy. Meanwhile, every polarimetric SAR image has different backscattering information of objects from each other and four polarimetric SAR data contain most basic and a large amount of redundancy information to improve matching. Therefore, we introduced logarithmically transformation and a stereo matching similarity measure into airborne full polarimetric SAR imagery. Firstly, in order to transform the multiplicative speckles into additivity ones and weaken speckles' influence on similarity measure, logarithmically transformation have to be taken to all images. Secondly, to prevent performance degradation of similarity measure caused by speckles, measure must be free or insensitive of additivity speckles. Thus, we introduced a stereo matching similarity measure, called Normalized Cross-Correlation (NCC), into full polarimetric SAR image matching. Thirdly, to take advantage of multi-polarimetric data and preserve the best similarity measure value, four measure values calculated between left and right single polarimetric SAR images are fused as final measure value for matching. The method was tested for matching under CASMSAR data. The results showed that the method delivered an effective

  6. Interferometric measurement of angles.

    PubMed

    Malacara, D; Harris, O

    1970-07-01

    A new interferometric device for measuring small angles or rotations with high accuracy is described. This instrument works by counting fringes formed by the rotation of a flat-parallel plate of glass illuminated with a collimated beam from a gas laser. Some possible applications are given.

  7. Integration of Canopy Height Information Derived from Stereo Imagery with SAR Backscatter Data to Improve Biomass Mapping

    NASA Astrophysics Data System (ADS)

    Sun, G.; Ranson, J.; Montesano, P. M.; Ni, W.

    2015-12-01

    Accurate forest biomass estimation over large areas is important for studies of global climate change and the carbon cycle. Synthetic Aperture Radar (SAR) is known to be effective for assessing forest biomass. SAR penetrates farther into forest canopies than optical sensors, so SAR data from forested areas can be related to standing woody biomass, especially at longer L and P bands wavelength. The effect of forest structure on radar signature reduces its sensitivity to biomass when the biomass reaches a threshold level (e.g. ~100Mg/ha at L-band). Therefore the ability for forest biomass mapping using only backscattering coefficients is limited. However, including height data in forest biomass mapping using SAR data will improve the sensitivity beyond saturation levels. There are many ways to get information related to forest canopy height including: 1) Lidar, a direct measurement of canopy height; 2) Height of scattering phase center (HSPC) from InSAR; 3) HSPC difference from two bands of InSAR, and 4) Polarimetric Interferometric SAR, which employs the polarization-dependent coherences. Photogrammetry (or stereo imagery) is another technique for quantifying forest vertical structure and is a traditional technique for the extraction of a digital surface model. The launch of spaceborne sensors, the application of digital cameras, the maturation of photogrammetry theory and the development of fully digital and automatic image processing make the application of photogrammetric methods feasible. Our previous studies using ALOS PRISM data have shown that the canopy height derived from PRISM stereo data were highly correlated with LVIS RH50 data. In this study we have integrated this canopy height with L-band SAR imagery data to map forest biomass in our test site in Howland, Maine. The point cloud data from multi-pair stereo imageries of five PRISM scenes were co-registered and used along with the USGS NED data to calculate the mean canopy height at 30m pixels. Multi

  8. Reconstruction in interferometric synthetic aperture microscopy: comparison with optical coherence tomography and digital holographic microscopy.

    PubMed

    Sheppard, Colin J R; Kou, Shan Shan; Depeursinge, Christian

    2012-03-01

    It is shown that the spatial frequencies recorded in interferometric synthetic aperture microscopy do not correspond to exact backscattering [as they do in unistatic synthetic aperture radar (SAR)] and that the reconstruction process based on SAR is therefore based on an approximation. The spatial frequency response is developed based on the three-dimensional coherent transfer function approach and compared with that in optical coherence tomography and digital holographic microscopy.

  9. Formation Flying for Distributed InSAR

    NASA Technical Reports Server (NTRS)

    Scharf, Daniel P.; Murray, Emmanuell A.; Ploen, Scott R.; Gromov, Konstantin G.; Chen, Curtis W.

    2006-01-01

    We consider two spacecraft flying in formation to create interferometric synthetic aperture radar (InSAR). Several candidate orbits for such in InSar formation have been previously determined based on radar performance and Keplerian orbital dynamics. However, with out active control, disturbance-induced drift can degrade radar performance and (in the worst case) cause a collision. This study evaluates the feasibility of operating the InSAR spacecraft as a formation, that is, with inner-spacecraft sensing and control. We describe the candidate InSAR orbits, design formation guidance and control architectures and algorithms, and report the (Delta)(nu) and control acceleration requirements for the candidate orbits for several tracking performance levels. As part of determining formation requirements, a formation guidance algorithm called Command Virtual Structure is introduced that can reduce the (Delta)(nu) requirements compared to standard Leader/Follower formation approaches.

  10. Polarimetric SAR Interferometry Evaluation in Mangroves

    NASA Technical Reports Server (NTRS)

    Lee, Seung-Kuk; Fatoyinbo,Temilola; Osmanoglu, Batuhan; Sun, Guoqing

    2014-01-01

    TanDEM-X (TDX) enables to generate an interferometric coherence without temporal decorrelation effect that is the most critical factor for a successful Pol-InSAR inversion, as have recently been used for forest parameter retrieval. This paper presents mangrove forest height estimation only using single-pass/single-baseline/dual-polarization TDX data by means of new dual-Pol-InSAR inversion technique. To overcome a lack of one polarization in a conventional Pol- InSAR inversion (i.e. an underdetermined problem), the ground phase in the Pol-InSAR model is directly estimated from TDX interferograms assuming flat underlying topography in mangrove forest. The inversion result is validated against lidar measurement data (NASA's G-LiHT data).

  11. Forest Volume and Biomass estimation from SAR/LIDAR/Optical Fusion in Chile

    NASA Astrophysics Data System (ADS)

    Kellndorfer, J. M.; Walker, W. S.; Goetz, S. J.; Cormier, T.; Kirsch, K.; Gonzalez, S.; Rombach, M.

    2009-12-01

    The paper reports on research to investigate ALOS/PALSAR L-band radar and optical time series data in conjunction with airborne lidar datasets to develop advanced data fusion algorithms for biomass and ecosystem structure measurements in support of the NASA DESDynI mission. The research is based on the acquisition of ALOS/PALSAR time series data beginning in 2007 and the timely confluence of these acquisitions with other highly relevant remote sensing and ground reference data sets in forested areas in Chile. Through collaboration with Digimapas Chile, the project has access to 75,000 km2 of 1-meter resolution full-waveform small footprint lidar (SFPL) data and 0.5 m resolution digital orthophoto imagery covering the commercial forests of Arauco, one of the largest cellulose producers in Latin America. Field inventory data from Arauco are used to test terrain and environmental influences on biomass estimation from empirical regression tree based data fusion approaches. The SAR data acquisitions available from PALSAR during the project time frame will span a five year period from 2007 to 2011, allowing investigations into how L-band time series data, similar to that expected from the DESDynI SAR (backscatter and interferometric coherence), can be used to build (1) the DESDynI biomass map product to be produced at the end of the “designed mission life” (i.e., 3 and/or 5/5+ years) and (2) annual maps of aboveground biomass change.

  12. A 3-D SAR approach to IFSAR processing

    SciTech Connect

    DOERRY,ARMIN W.; BICKEL,DOUGLAS L.

    2000-03-01

    Interferometric SAR (IFSAR) can be shown to be a special case of 3-D SAR image formation. In fact, traditional IFSAR processing results in the equivalent of merely a super-resolved, under-sampled, 3-D SAR image. However, when approached as a 3-D SAR problem, a number of IFSAR properties and anomalies are easily explained. For example, IFSAR decorrelation with height is merely ordinary migration in 3-D SAR. Consequently, treating IFSAR as a 3-D SAR problem allows insight and development of proper motion compensation techniques and image formation operations to facilitate optimal height estimation. Furthermore, multiple antenna phase centers and baselines are easily incorporated into this formulation, providing essentially a sparse array in the elevation dimension. This paper shows the Polar Format image formation algorithm extended to 3 dimensions, and then proceeds to apply it to the IFSAR collection geometry. This suggests a more optimal reordering of the traditional IFSAR processing steps.

  13. SARS Basics

    MedlinePlus

    ... waiting room or office. Top of Page CDC’s response to SARS during the 2003 outbreak CDC worked ... Center to provide round-the-clock coordination and response. Committed more than 800 medical experts and support ...

  14. Mangrove Blue Carbon stocks and change estimation from PolInSAR, Lidar and High Resolution Stereo Imagery combined with Forest Cover change mapping

    NASA Astrophysics Data System (ADS)

    Zalles, V.; Fatoyinbo, T. E.; Simard, M.; Lagomasino, D.; Lee, S. K.; Trettin, C.; Feliciano, E. A.; Hansen, M.; John, P.

    2015-12-01

    Mangroves and tidal wetlands have the highest carbon density among terrestrial ecosystems. Although they only represent 3 % of the total forest area (or 0.01 % of land area), C emissions from mangrove destruction alone at current rates could be equivalent to 10 % of carbon emissions from deforestation. One of the main challenges to implementing carbon mitigation projects is measuring carbon, efficiently, effectively, and safely. In mangroves especially, the extreme difficulty of the terrain has hindered the establishment of sufficient field plots needed to accurately measure carbon on the scale necessary to relate remotely sensed measurements with field measurements at accuracies required for REDD and other C trading mechanisms. In this presentation we will showcase the methodologies for, and the remote sensing products necessary to implement MRV (monitoring, reporting and verification) systems in Coastal Blue Carbon ecosystems. Specifically, we will present new methods to estimate aboveground biomass stocks and change in mangrove ecosystems using remotely sensed data from Interferometric SAR from the TanDEM-X mission, commercial airborne Lidar, High Resolution Stereo-imagery, and timeseries analysis of Landsat imagery in combination with intensive field measurements of above and belowground carbon stocks. Our research is based on the hypothesis that by combining field measurements, commercial airborne Lidar, optical and Pol-InSAR data, we are able to estimate Mangrove blue carbon storage with an error under 20% at the project level and permit the evaluation of UNFCCC mechanisms for the mitigation of carbon emissions from coastal ecosystems.

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

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  16. Program Merges SAR Data on Terrain and Vegetation Heights

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  17. Monitoring urban subsidence based on SAR lnterferometric point target analysis

    USGS Publications Warehouse

    Zhang, Y.; Zhang, Jiahua; Gong, W.; Lu, Zhiming

    2009-01-01

    lnterferometric point target analysis (IPTA) is one of the latest developments in radar interferometric processing. It is achieved by analysis of the interferometric phases of some individual point targets, which are discrete and present temporarily stable backscattering characteristics, in long temporal series of interferometric SAR images. This paper analyzes the interferometric phase model of point targets, and then addresses two key issues within IPTA process. Firstly, a spatial searching method is proposed to unwrap the interferometric phase difference between two neighboring point targets. The height residual error and linear deformation rate of each point target can then be calculated, when a global reference point with known height correction and deformation history is chosen. Secondly, a spatial-temporal filtering scheme is proposed to further separate the atmosphere phase and nonlinear deformation phase from the residual interferometric phase. Finally, an experiment of the developed IPTA methodology is conducted over Suzhou urban area. Totally 38 ERS-1/2 SAR scenes are analyzed, and the deformation information over 3 546 point targets in the time span of 1992-2002 are generated. The IPTA-derived deformation shows very good agreement with the published result, which demonstrates that the IPTA technique can be developed into an operational tool to map the ground subsidence over urban area.

  18. Imaging interferometric microscopy.

    PubMed

    Schwarz, Christian J; Kuznetsova, Yuliya; Brueck, S R J

    2003-08-15

    We introduce and demonstrate a new microscopy concept: imaging interferometric microscopy (IIM), which is related to holography, synthetic-aperture imaging, and off-axis-dark-field illumination techniques. IIM is a wavelength-division multiplex approach to image formation that combines multiple images covering different spatial-frequency regions to form a composite image with a resolution much greater than that permitted by the same optical system using conventional techniques. This new type of microscopy involves both off-axis coherent illumination and reinjection of appropriate zero-order reference beams. Images demonstrate high resolution, comparable with that of a high-numerical-aperture (NA) objective, while they retain the long working distance, the large depth of field, and the large field of view of a low-NA objective. A Fourier-optics model of IIM is in good agreement with the experiment. PMID:12943079

  19. Characterizing hydrologic changes of Great Dismal Swamp using SAR/InSAR technology

    NASA Astrophysics Data System (ADS)

    Kim, J. W.; Lu, Z.; Zhu, Z.

    2015-12-01

    Great Dismal Swamp is one of the largest, northernmost peatlands on the Atlantic Coastal Plain, and the swamp is underlain by a thick water-logged organic soil layer (peat) made up of dead and decaying plant material. The peatlands play a role as the sink of large amount of soil organic carbon and methane. However, the disturbance of the peatland negatively impacted the ecosystem and contributed to the climate change caused by the released greenhouse gas. Our SAR/InSAR methods observed the hydrologic changes in the peatlands, which is a key factor to conserve the wetland, through several methods. First, we compared averaged SAR intensity from C- and L-band SAR sensors with groundwater level changes, and deduced a linear relationship between the SAR backscattering intensity and the groundwater level change. Second, we extracted the inundated area during wet season from InSAR coherence. Third, we measured the relative water level changes in the inundated area using the interferometric phases. Finally, we estimated the groundwater level changes corresponding to the soil moisture changes from time-series InSAR method. Our results can provide the unique opportunity to understand the occurring hydrologic and vegetation changes in the Great Dismal Swamp.

  20. Analysis of Agricultural Scenes Based on SAR Interferometry

    NASA Astrophysics Data System (ADS)

    Nico, G.; Mascolo, L.; Pellegrinelli, A.; Giretti, D.; Soccodato, F. M.; Catalao, J.

    2015-05-01

    The aim of this work is to study the temporal behavior of interferometric coherence of natural scenes and use it to discriminate different classes of targets. The scattering properties of targets within a SAR resolution cell depend on their spatial distribution and dielectric constant. We focus on agriculture scenes. In case of bare soils, the radar cross section depends on surface roughness and soil moisture. Both quantities are strongly related to agriculture practices. The interferometric coherence can be modelled as the factorization of correlation terms due to spatial and temporal baselines, terrain roughness, soil moisture and residual noise. We use multivariate analysis methodologies to discriminate scattering classes exhibiting different temporal behaviors of the interferometric coherence. For each class, the temporal evolution of the interferometric phase and radar cross-section are studied.

  1. [Air-borne disease].

    PubMed

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

    2003-11-01

    Respiratory protection is a factor which worries nursing professionals who take care of patients susceptible of transmitting microorganisms through the air more as every day passes. This type of protection covers the use of surgical or hygienic masks against the transmission of infection by airborne drops to the use of highly effective masks or respirators against the transmission of airborne diseases such as tuberculosis or SARS, a recently discovered disease. The adequate choice of this protective device and its correct use are fundamental in order to have an effective protection for exposed personnel. The authors summarize the main protective respiratory devices used by health workers, their characteristics and degree of effectiveness, as well as the circumstances under which each device is indicated for use. PMID:14705591

  2. Interferometric synthetic-aperature radar (InSAR): Chapter 5

    USGS Publications Warehouse

    Dzurisin, Daniel; Lu, Zhong

    2007-01-01

    Geodesists are, for the most part, a patient and hardworking lot. A day spent hiking to a distant peak, hours spent waiting for clouds to clear a line-of-sight between observation points, weeks spent moving methodically along a level line – such is the normal pulse of the geodetic profession. The fruits of such labors are all the more precious because they are so scarce. A good day spent with an electronic distance meter (EDM) or level typically produces fewer than a dozen data points. A year of tiltmeter output sampled at ten-minute intervals constitutes less than half a megabyte of data. All of the leveling data ever collected at Yellowstone Caldera fit comfortably on a single PC diskette. These quantities are trivial by modern data-storage standards, in spite of the considerable efforts expended to produce them.

  3. Recovering Seasat SAR Data

    NASA Astrophysics Data System (ADS)

    Logan, T. A.; Arko, S. A.; Rosen, P. A.

    2013-12-01

    supposedly 'steadily' changing millisecond (MSEC) timing values. The elevated BER made even a basic linear fit difficult. In addition, the MSEC field often shows a 'stair step' function, assumed to be a spacecraft clock malfunction. To fix these issues, three separate levels of time filtering were applied. After the initial three-pass time filter, a fourth procedure located and removed discontinuities - missing data sections that occurred randomly throughout the data takes - by inserting random valued lines into the effected data file and repeated value lines into the corresponding header file. Finally, a fifth pass through the metadata was required to fix remaining start time anomalies. After the data were filtered, all times were linearly increasing, and all discontinuities filled, images could finally be formed. ASF DAAC utilized a custom version of ROI, the Repeat Orbit Interferometric SAR processor, to focus the data. Special focusing tasks for Seasat included dealing with Doppler ambiguity issues and filtering out 'spikes' in the power spectra. Once these obstacles were overcome via additional pre-processing software developed in house, well-focused SAR imagery was obtained from approximately 80% the ASF DAAC archives. These focused products, packaged in either HDF5 or geotiff formats with XML metadata, are downloadable from ASF DAAC free of charge.

  4. Use of SPOT and ERS-1 SAR data to study the tectonic and climatic history of arid regions

    NASA Technical Reports Server (NTRS)

    Farr, Tom G.; Peltzer, Gilles F.

    1993-01-01

    In order to separate the effects of the different tectonic and climatic processes on the shapes of desert piedmonts, a modified conic equation was fitted to digital topographic data for individual alluvial fans in Death Valley (California, U.S.). The topographic data were obtained from a SPOT panchromatic stereo pair and from the airborne interferometric SAR (Synthetic Aperture Radar) (TOPSAR). The conic fit allows parameters for the epex position, slope, and radial curvature to be compared with unit age, uplift rate, and climatic conditions. Preliminary results indicate that slope flattens with age and radial curvature is concave up, but decreases with age. Work is continuing on correlation of fit residuals and apex position with fan unit age. This information will help in the determination of tectonic uplift rates and the climatic history of the western U.S. ERS-1 SAR images were used to study an area of western China where a large strike slip fault crosses a series of alluvial fans and stream valleys. Previous analysis of SPOT panchromatic images of the area shows that offsets fans and streams can be recognized. Measurement of the rate of motion of this fault will help in the overall model of deformation of the Asian tectonic plate in response to the collision of the Indian plate.

  5. Development of an Advanced Technique to Correct Along-Track InSAR-Derived Surface Current Fields for Contributions of Wave Motions

    NASA Astrophysics Data System (ADS)

    Smith, C.; Romeiser, R.; Reniers, A.; MacMahan, J.

    2014-12-01

    The feasibility of surface current measurements by airborne and spaceborne along-track interferometric synthetic aperture radar (along-track InSAR) has been demonstrated on a number of occasions. Since the Doppler shifts detected by the radar include contributions of surface wave motions, a correction for these contributions has to be applied, which is often estimated as a mean correction for the entire current field on the basis of a simple theoretical model. In coastal areas and river estuaries with complex current and wave patterns, this approach is not adequate because one has to account for spatial variations in the wave field and in the corresponding corrections for the current field, which can be on the same order of magnitude as the actual surface currents of interest. Here we test the ability of a numerical near-shore hindcast model (Delft3D) to produce a wave field to be used for more appropriate computations of corrections for the along-track InSAR data. Our study was conducted at the mouth of the Columbia River on the West Coast of the U.S. during the spring of 2013. Over the course of the experiment, seven TerraSAR-X along-track InSAR images were acquired as well as a variety of in-situ data sets, such as trajectories of GPS-equipped Lagrangian drifters and velocity profiles from acoustic Doppler current profilers (ADCP). We use the in-situ data to validate our Delft3D model results, and we try to relate spatially varying differences between the measured and simulated surface currents and the TerraSAR-X derived Doppler velocities to the wave spectra obtained from Delft3D and to wave patterns observed in the SAR images. The long-term objective of this work is to derive the wave information and the corresponding velocity corrections from signatures contained in the along-track InSAR data set itself, such that a completely self-consistent correction of along-track InSAR-derived surface current fields for the contributions of spatially varying wave motions

  6. From Phase to Fringe: How InSAR Might Work for You

    NASA Astrophysics Data System (ADS)

    Bryson, G.; Buechler, B.; Gens, R.; Hogenson, K.; Shapran, M.; Short, G.

    2010-12-01

    The Alaska Satellite Facility (ASF) operates a premier NASA Data Center that processes, archives, and distributes remote-sensing data to scientific users, specifically focused on synthetic aperture radar (SAR). The ASF SAR Data Center provides users the ability to search and order Interferometric SAR (InSAR) pairs through the online User Remote Sensing Access (URSA) interface and has recently expanded the data product offerings to include custom InSAR products. This presentation provides an overview of new InSAR search and order features in URSA, an introduction to the InSAR product offered at ASF, and a discussion on how these products are useful to a broad range of research areas.

  7. Observations of the sub-glacial hydrology of the Malaspina Glacier, using spaceborne InSAR

    NASA Astrophysics Data System (ADS)

    Ford, A. L.; Forster, R.; Bruhn, R. L.

    2009-12-01

    Two-pass Interferometric SAR (InSAR) using 1- and 3-day pairs of ERS-1 and -2 SAR data has been applied to the observation of ice subsidence and rebound, interpreted as resulting from the influx and drainage of water through sub-glacial and/or englacial cavities. The Malaspina (Alaska), the largest piedmont glacier in the world, is characterised by slow or stagnant horizontal ice flow, allowing phase changes due to vertical ice movement to dominate. InSAR analysis has been augmented using Digital Surface Models (DSM) from the Shuttle Radar Topography Mission (SRTM) and interpretations of sub-glacial drainage patterns are presented.

  8. Observations of the sub-glacial hydrology of the Malaspina Glacier, using spaceborne InSAR

    NASA Astrophysics Data System (ADS)

    Ford, A. L.; Forster, R. R.; Bruhn, R. L.

    2011-12-01

    Two-pass Interferometric SAR (InSAR) using 1- and 3-day pairs of ERS-1 and -2 SAR data has been applied to the observation of ice subsidence and rebound, interpreted as resulting from the influx and drainage of water through sub-glacial and/or englacial cavities. The Malaspina (Alaska), the largest piedmont glacier in the world, is characterised by slow or stagnant horizontal ice flow, allowing phase changes due to vertical ice movement to dominate. InSAR analysis has been augmented using Digital Surface Models (DSM) from the Shuttle Radar Topography Mission (SRTM) and interpretations of sub-glacial drainage patterns are presented.

  9. MATLAB toolbox for EnviSAT InSAR data processing, visualization, and analysis

    NASA Astrophysics Data System (ADS)

    Zhang, Zhidong; Ma, Zunjing; Chen, Ganlu; Chen, Yan; Lu, Yilong

    2012-10-01

    Interferometric Synthetic Aperture Radar (InSAR) is an emerging technology with increasing applications in for high precision interferometry and 3-D digital elevation model (DEM) ground mapping. This paper presents a user-friendly MATLAB Toolbox for enhanced InSAR applications based on European Space Agency (ESA) SAR missions. The developed MATLAB tools can provide high quality and flexible data processing, visualization and analyzing functions by tapping on MATLAB's rich and powerful mathematics and graphics tools. Case studies are presented to with enhanced InSAR and DEM processing, visualization, and analysis examples.

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

    NASA Astrophysics Data System (ADS)

    Pottier, E.

    2010-06-01

    . In order to promote the exploitation of Polarimetric Spaceborne data, as it is starting today to proliferate with the launch of these Polarimetric SAR sensors, the PolSARpro Software, developed under contract to ESA and that is a toolbox for the scientific exploitation of Polarimetric SAR and Polarimetric-Interferometric data and a tool for high-level education in radar polarimetry, has been expanded and refined to include all elements necessary for the demonstration of a number of key applications. The PolSARpro Software, that already was supporting an important range of airborne and spaceborne polarimetric data sources, supports now the following additional data sources: ALOS-PALSAR (Dual-Pol fine mode and Quad-Pol mode), TerraSAR-X (Dual-pol mode) and Radarsat-2 (Dual-Pol fine mode and Quad-Pol fine and standard modes), by offering a platform dedicated interface for E.O Scientific Investigator. A number of illustrations of key applications has been developed for the demonstration and the promotion of the Polarimetric Spaceborne missions, that are consistent with the activities incorporated in the GMES Services Element (GSE). The aim of this communication is to present the current state of the art in SAR Polarimetry ranging from theory to applications, with special emphasis in the analysis of data provided by the new Polarimetric Spaceborne SAR sensors, and samples of real polarimetric data will be presented for use in real-life examples of key applications.

  11. Two target height effects on interferometric synthetic aperture radar coherence

    SciTech Connect

    YOCKY,DAVID A.; JAKOWATZ JR.,CHARLES V.

    2000-03-07

    Useful products generated from interferometric synthetic aperture radar (IFSAR) complex data include height measurement, coherent change detection, and classification. The IFSAR coherence is a spatial measure of complex correlation between two collects, a product of IFSAR signal processing. A tacit assumption in such IFSAR signal processing is that one height target exists in each range-Doppler cell. This paper presents simulations of IFSAR coherence if two targets with different heights exist in a given range-Doppler cell, a condition in IFSAR collections produced by layover. It also includes airborne IFSAR data confirming the simulation results. The paper concludes by exploring the implications of the results on IFSAR classification and height measurements.

  12. UAVSAR: InSAR and PolSAR Test Bed for the Proposed NI-SAR Mission

    NASA Astrophysics Data System (ADS)

    Jones, C. E.; Hensley, S.; Lou, Y.

    2014-12-01

    UAVSAR, which first became operational in 2009, has served as an operational testbed for the NI-SAR L-band radar concept and a unique instrument in its own right. UAVSAR supports a broad array of basic and applied geoscience, covering on smaller scale all the disciplines NI-SAR would be able to address on a global scale. Although designed specifically to provide high accuracy repeated flight tracks and precise imaging geometry for InSAR-based solid earth studies, its fully polarimetric operation, low noise, and consistent calibration accuracy has made it a premier instrument for PolSAR-based studies also. Since 2009 it has successfully imaged more than 16 million km2 and >4300 quad-polarimetric data products are now publicly available online. Upgrades made in the last year to automate the repeat track processing serve as a model for generating large volumes of InSAR products: Since January 2014 more than 700 interferometric products have been released, exceeding the output of all previous years combined. Standardly available products now include browse images of all InSAR acquisitions and coregistered single-look complex image stacks suitable for standard time series analysis. Here we present an overview of the wide range of studies utilizing UAVSAR data including those based on polarimetry and pair-wise and times series interferometry, highlighting both the unique capabilities of UAVSAR and the ways in which NI-SAR would be able to dramatically extend the capabilities. This research was conducted at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  13. Multifrequency InSAR height reconstruction through maximum likelihood estimation of local planes parameters.

    PubMed

    Pascazio, Vito; Schirinzi, Gilda

    2002-01-01

    In this paper, a technique that is able to reconstruct highly sloped and discontinuous terrain height profiles, starting from multifrequency wrapped phase acquired by interferometric synthetic aperture radar (SAR) systems, is presented. We propose an innovative unwrapping method, based on a maximum likelihood estimation technique, which uses multifrequency independent phase data, obtained by filtering the interferometric SAR raw data pair through nonoverlapping band-pass filters, and approximating the unknown surface by means of local planes. Since the method does not exploit the phase gradient, it assures the uniqueness of the solution, even in the case of highly sloped or piecewise continuous elevation patterns with strong discontinuities. PMID:18249716

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  15. Diverse deformation patterns of Aleutian volcanoes from InSAR

    USGS Publications Warehouse

    Lu, Zhiming; Dzurisin, D.; Wicks, C.; Power, J.

    2008-01-01

    Interferometric synthetic aperture radar (InSAR) is capable of measuring ground-surface deformation with centimeter-to-subcentimeter precision at a spatial resolution of tens of meters over an area of hundreds to thousands of square kilometers. With its global coverage and all-weather imaging capability, InSAR has become an increasingly important measurement technique for constraining magma dynamics of volcanoes over remote regions such as the Aleutian Islands. The spatial pattern of surface deformation data derived from InSAR images enables the construction of detailed mechanical models to enhance the study of magmatic processes. This paper summarizes the diverse deformation patterns of the Aleutian volcanoes observed with InSAR and demonstrates that deformation patterns and associated magma supply mechanisms in the Aleutians are diverse and vary between volcanoes. These findings provide a basis for improved models and better understanding of magmatic plumbing systems.

  16. Forest Profiling with Multiple Observation Interferometric Synthetic Aperture Radar

    NASA Astrophysics Data System (ADS)

    Treuhaft, R. N.; Chapman, B. D.; Dutra, L. V.; Dos Santos, J. R.; Goncalves, F. G.; Mura, J. C.; Freitas, C. D.; Graca, P. M.; Drake, J.

    2006-12-01

    Measurements of the vertical structure of forest vegetation bear on ecosystem state, such as biodiversity, carbon dynamics, and fire susceptibility, and the estimation of forest biomass. Global monitoring of vertical vegetation structure is one of the most important and as yet unrealized goals of forest remote sensing. The Interferometric Synthetic Aperture Radar (InSAR) phase and coherence observations are directly sensitive to the vertical distribution of electromagnetic dielectric in the forest medium. This dielectric distribution in turn depends on vegetation density as a function of the vertical coordinate. Multiple InSAR observations--multiple baseline, multiple frequency, and/or multiple polarization--must be used to uniquely estimate vegetation density profiles. This talk explains the need for multiple observation strategies and the benefits of multiple- baseline, multiple-frequency, and multiple-polarization strategies. Multiple baseline tropical forest profiles from C-band (wavelength=0.056 m) InSAR will be shown, as well as results from L-band (0.25 m) few-baseline observations over La Selva Biological Station, Costa Rica. Both surface-deformation measurements and those relevant to vertical-vegetation structure may result from a single InSAR mission design, provided, for example, that multiple nonzero baselines are flown along with the zero-baseline configuration preferred for deformation. The possibility of mutually improving the accuracy of deformation and structure in a simultaneous- measurement scenario will be discussed. There is also potential synergy with other remote sensing missions, such as the Tandem X InSAR mission, for delivering forest structure.

  17. Mobile radio interferometric geodetic systems

    NASA Technical Reports Server (NTRS)

    Macdoran, P. F.; Niell, A. E.; Ong, K. M.; Resch, G. M.; Morabito, D. D.; Claflin, E. S.; Lockhart, T. G.

    1978-01-01

    Operation of the Astronomical Radio Interferometric Earth Surveying (ARIES) in a proof of concept mode is discussed. Accuracy demonstrations over a short baseline, a 180 km baseline, and a 380 km baseline are documented. Use of ARIES in the Sea Slope Experiment of the National Geodetic Survey to study the apparent differences between oceanographic and geodetic leveling determinations of the sea surface along the Pacific Coast is described. Intergration of the NAVSTAR Global Positioning System and a concept called SERIES (Satellite Emission Radio Interferometric Earth Surveying) is briefly reviewed.

  18. Calculation and Error Analysis of a Digital Elevation Model of Hofsjokull, Iceland from SAR Interferometry

    NASA Technical Reports Server (NTRS)

    Barton, Jonathan S.; Hall, Dorothy K.; Sigurosson, Oddur; Williams, Richard S., Jr.; Smith, Laurence C.; Garvin, James B.

    1999-01-01

    Two ascending European Space Agency (ESA) Earth Resources Satellites (ERS)-1/-2 tandem-mode, synthetic aperture radar (SAR) pairs are used to calculate the surface elevation of Hofsjokull, an ice cap in central Iceland. The motion component of the interferometric phase is calculated using the 30 arc-second resolution USGS GTOPO30 global digital elevation product and one of the ERS tandem pairs. The topography is then derived by subtracting the motion component from the other tandem pair. In order to assess the accuracy of the resultant digital elevation model (DEM), a geodetic airborne laser-altimetry swath is compared with the elevations derived from the interferometry. The DEM is also compared with elevations derived from a digitized topographic map of the ice cap from the University of Iceland Science Institute. Results show that low temporal correlation is a significant problem for the application of interferometry to small, low-elevation ice caps, even over a one-day repeat interval, and especially at the higher elevations. Results also show that an uncompensated error in the phase, ramping from northwest to southeast, present after tying the DEM to ground-control points, has resulted in a systematic error across the DEM.

  19. New formulation for interferometric synthetic aperture radar for terrain mapping

    SciTech Connect

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

    1994-04-01

    The subject of interferometric synthetic aperture radar (IFSAR) for high-accuracy terrain elevation mapping continues to gain importance in the arena of radar signal processing. Applications to problems in precision terrain-aided guidance and automatic target recognition, as well as a variety of civil applications, are being studied by a number of researchers. Not unlike many other areas of SAR processing, the subject of IFSAR can at first glance appear to be somewhat mysterious. In this paper we show how the mathematics of IFSAR for terrain elevation mapping using a pair of spotlight mode SAR collections can be derived in a very straightforward manner. Here, we employ an approach that relies entirely on three-dimensional Fourier transforms, and utilizes no reference to range equations or Doppler concepts. The result is a simplified explanation of the fundamentals of interferometry, including an easily-seen link between image domain phase difference and terrain elevation height. The derivation builds upon previous work by the authors in which a framework for spotlight mode SAR image formation based on an analogy to three-dimensional computerized axial tomography (CAT) was developed. After outlining the major steps in the mathematics, we show how a computer simulator which utilizes three-dimensional Fourier transforms can be constructed that demonstrates all of the major aspects of IFSAR from spotlight mode collections.

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

    NASA Astrophysics Data System (ADS)

    Jones, Cathleen; Blom, Ronald; Latini, Daniele

    2014-05-01

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

  1. Absolute radiometric calibration of the CCRS SAR

    NASA Astrophysics Data System (ADS)

    Ulander, Lars M. H.; Hawkins, Robert K.; Livingstone, Charles E.; Lukowski, Tom I.

    1991-11-01

    Determining the radar scattering coefficients from SAR (synthetic aperture radar) image data requires absolute radiometric calibration of the SAR system. The authors describe an internal calibration methodology for the airborne Canada Centre for Remote Sensing (CCRS) SAR system, based on radar theory, a detailed model of the radar system, and measurements of system parameters. The methodology is verified by analyzing external calibration data acquired over a 6-month period in 1988 by the C-band radar using HH polarization. The results indicate that the overall error is +/- 0.8 dB (1-sigma) for incidence angles +/- 20 deg from antenna boresight. The dominant error contributions are due to the antenna radome and uncertainties in the elevation angle relative to the antenna boresight.

  2. Calibration of a polarimetric imaging SAR

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  3. Wideband Interferometric Sensing and Imaging Polarimetry

    NASA Technical Reports Server (NTRS)

    Verdi, James Salvatore; Kessler, Otto; Boerner, Wolfgang-Martin

    1996-01-01

    Wideband Interferometric Sensing and Imaging Polarimetry (WISIP) has become an important, indispensible tool in wide area military surveillance and global environmental monitoring of the terrestrial and planetary covers. It enables dynamic, real time optimal feature extraction of significant characteristics of desirable targets and/or target sections with simultaneous suppression of undesirable background clutter and propagation path speckle at hitherto unknown clarity and never before achieved quality. WISIP may be adopted to the detection, recognition, and identification (DRI) of any stationary, moving or vibrating targets or distributed scatterer segments versus arbitrary stationary, dynamical changing and/or moving geo-physical/ecological environments, provided the instantaneous 2x2 phasor and 4x4 power density matrices for forward propagation/backward scattering, respectively, can be measured with sufficient accuracy. For example, the DRI of stealthy, dynamically moving inhomogeneous volumetric scatter environments such as precipitation scatter, the ocean/sea/lake surface boundary layers, the littoral coastal surf zones, pack ice and snow or vegetative canopies, dry sands and soils, etc. can now be successfully realized. A comprehensive overview is presented on how these modern high resolution/precision, complete polarimetric co-registered signature sensing and imaging techniques, complemented by full integration of novel navigational electronic tools, such as DGPS, will advance electromagnetic vector wave sensing and imaging towards the limits of physical realization. Various examples utilizing the most recent image data take sets of airborne, space shuttle, and satellite imaging systems demonstrate the utility of WISIP.

  4. Use of SAR in Regional Methane Exchange Studies

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  5. Quantum interferometric measurements of temperature

    NASA Astrophysics Data System (ADS)

    Jarzyna, Marcin; Zwierz, Marcin

    2015-09-01

    We provide a detailed description of the quantum interferometric thermometer, which is a device that estimates the temperature of a sample from the measurements of the optical phase. We rigorously analyze the operation of such a device by studying the interaction of the optical probe system prepared in a single-mode Gaussian state with a heated sample modeled as a dissipative thermal reservoir. We find that this approach to thermometry is capable of measuring the temperature of a sample in the nanokelvin regime. Furthermore, we compare the fundamental precision of quantum interferometric thermometers with the theoretical precision offered by the classical idealized pyrometers, which infer the temperature from a measurement of the total thermal radiation emitted by the sample. We find that the interferometric thermometer provides a superior performance in temperature sensing even when compared with this idealized pyrometer. We predict that interferometric thermometers will prove useful for ultraprecise temperature sensing and stabilization of quantum optical experiments based on the nonlinear crystals and atomic vapors.

  6. Single Baseline Tomography SAR for Forest Above Ground Biomass Estimation

    NASA Astrophysics Data System (ADS)

    Li, Wenmei; Chen, Erxue; Li, Zengyuan; Wang, Xinshuang; Feng, Qi

    2013-01-01

    Single baseline tomography SAR is used for forest height estimation as its little restriction on the number of baselines and configurations of tracks in recent years. There existed two kinds of single baseline tomography SAR techniques, the polarimetric coherence tomography (PCT) and the sum of Kronecker product (SKP), algebraic synthesis (AS) and Capon spectral estimator approach (SKP-AS-Capon). Few researches on forest above ground biomass (AGB) estimation are there using single baseline tomography SAR. In this paper, PCT and SKP-AS-Capon approaches are proposed for forest AGB estimation. L-band data set acquired by E-SAR airborne system in 2003 for the forest test site in Traunstein, is used for this experiment. The result shows that single baseline polarimetric tomography SAR can obtain forest AGB in forest stand scale, and SKP-AS-Capon method has better detailed vertical structure information, while the Freeman 3-component combined PCT approach gets a homogenous vertical structure in forest stand.

  7. An efficient compressive sensing based PS-DInSAR method for surface deformation estimation

    NASA Astrophysics Data System (ADS)

    Li, J. T.; Xu, H. P.; Shan, L.; Liu, W.; Chen, G. Z.

    2016-11-01

    Permanent scatterers differential interferometric synthetic aperture radar (PS-DInSAR) is a technique for detecting surface micro-deformation, with an accuracy at the centimeter to millimeter level. However, its performance is limited by the number of SAR images available (normally more than 20 are needed). Compressive sensing (CS) has been proven to be an effective signal recovery method with only a very limited number of measurements. Applying CS to PS-DInSAR, a novel CS-PS-DInSAR method is proposed to estimate the deformation with fewer SAR images. By analyzing the PS-DInSAR process in detail, first the sparsity representation of deformation velocity difference is obtained; then, the mathematical model of CS-PS-DInSAR is derived and the restricted isometry property (RIP) of the measurement matrix is discussed to validate the proposed CS-PS-DInSAR in theory. The implementation of CS-PS-DInSAR is achieved by employing basis pursuit algorithms to estimate the deformation velocity. With the proposed method, DInSAR deformation estimation can be achieved by a much smaller number of SAR images, as demonstrated by simulation results.

  8. L-Band SAR Interferometry for Mapping Arctic Landfast Ice

    NASA Astrophysics Data System (ADS)

    Meyer, F. J.; Mahoney, A.; Eicken, H.; Denny, C. L.

    2010-12-01

    Landfast sea ice is a key element of the arctic coastal system. Its presence can mitigate the effect of winter storms on the coast and impact the degree of coastal erosion. Landfast ice is also of great importance to coastal communities who use the ice for travel and to hunt. Furthermore, its presence and stability is of considerable economic importance for offshore oil and gas development in parts of the Arctic. In recent years, there has been a reduced presence of landfast sea ice throughout the Arctic. E.g., along Alaska’s northern coast, although the annual maximum extent has changed little, landfast sea ice appears to forming later and breaking up earlier than it did during the 1970s. As a result of these changes together with increasing commercial interest in coastal areas of the Arctic, it has become important in recent years to be able to identify landfast ice from remote sensing data. In recent years methods have been developed to extract the seaward landfast ice edge from series of remote sensing images, with most of them relying on incoherent change detection in optical, infrared, or radar amplitude imagery. While such approaches provide valuable results, some still lack the required level of robustness and all lack the ability to fully automate the detection and mapping of landfast ice over large areas and long time spans. Furthermore, it is often not so much the presence, but the stability of landfast ice that matters most in practical applications, in particular use of sea ice as a platform. This paper presents an alternative approach to mapping landfast ice extent and assessing ice stability. The method is based on interferometric processing of L-band SAR image pairs acquired by the spaceborne SAR sensor PALSAR on board the Japanese Advanced Land Observing Satellite (ALOS). With interferometric phase and interferometric coherence, SAR interferometry (InSAR) comprises two measurements that have the potential for assessing both landfast ice extent

  9. Measuring Thermokarst Subsidence Using InSAR: Potential and Pitfalls

    NASA Astrophysics Data System (ADS)

    Liu, L.; Schaefer, K. M.; Chen, A. C.; Gusmeroli, A.; Zebker, H. A.; Zhang, T.

    2014-12-01

    Thawing of ice-rich permafrost results in irregular, depressed landforms known as thermokarst terrain. The significant subsidence leading to thermokarst features can expand lakes, drain lakes, accelerate thaw, disturb the soil column, and promote erosion. Consequently, it affects many permafrost-region processes including vegetation succession, hydrology, and carbon storage and cycling. Many remote sensing studies identify thermokarst landforms and catalog their ever-changing areas. Yet the intrinsic dynamic thermokarst process, namely surface subsidence, remains a challenge to map and is seldom examined using remote sensing methods. Interferometric Synthetic Aperture Radar (InSAR) is a remote sensing technique that uses a time-series of satellite SAR images to measure cm-level land surface deformation. We demonstrate the capabilities and limitations of space-borne InSAR data to map thermokarst subsidence at a site located near Prudhoe Bay, on the North Slope of Alaska. A pipeline access road was constructed at this site in the 1970s, and is likely to have triggered the thawing of the region's permafrost, causing subsequent expansion of thermokarst-landform terrain. Our InSAR analysis using ALOS PALSAR images reveals that the thermokarst landforms in this region have undergone up to 10 cm of surface subsidence each summer from 2007 to 2010. This pilot study demonstrates the application of InSAR to map localized mass movement in permafrost terrain. We also illustrate how the effectiveness and accuracy of InSAR measurements are limited by several factors such as loss of interferometric coherence due to fast changes of ground surface conditions, spatial and temporal resolutions of InSAR data, and difficulty separating long-term and seasonal deformation signals.

  10. Monomode Fibre Optic Interferometric Sensors.

    NASA Astrophysics Data System (ADS)

    Leilabady, P. Akhavan

    Available from UMI in association with The British Library. Optical fibre sensors are playing an increasingly important role in industrial, medical and military application. Not only are conventional electrically based sensors being gradually replaced by their fibre optic analogues, but also fibre optic sensors are being deployed in special applications where electrically based sensors are unsuitable. Their immunity to electromagnetic interference and inherent high measurement resolution give optical fibre sensors an advantage in diverse applications, including the aerospace and power generation industry and in medicine. The theme of this thesis is interferometric techniques for the recovery of measurand induced modulations of the the fibre guided optical beam. Interferometry offers high measurement resolutions, which makes it the preferred choice for optical processing in certain sensor systems. Interferometric techniques developed for the recovery of the optical phase, polarisation ellipticity and polarisation azimuth are described. However, there are a number of problems, such as the very limited operating range and long term stability that hinder practical implementation of interferometric sensors. These problems are addressed and novel optical processing circuitry based on interferometric detection of phase and polarisation state are introduced which facilitates the development of practical all fibre sensors. Our discussions will start by a general overview of the fibre optic sensor technology, Chapter 1, introducing the principle of sensing by light and the three major categories of fibre optic sensors; multimode fibre intensity modulated sensors, monomode fibre phase modulated sensors and birefringent fibre polarisation state modulated sensors. In Chapter 3, the category of sensors based on phase modulation is addressed describing research carried out into developing an all-fibre optic vortex shedding flowmeter, illustrating interferometric techniques for

  11. Development of a folded compact range and its application in performing coherent change detection and interferometric ISAR measurement

    SciTech Connect

    Sorensen, K.W.; Zittel, D.H.; Littlejohn, J.H.

    1996-09-01

    A folded compact range configuration has been developed at the Sandia National Laboratories` compact range antenna and radar cross section measurement facility as a means of performing indoor, environmentally controlled far-field simulations of synthetic aperture radar (SAR) measurements of distributed target samples (i.e. gravel, sand, etc.). In particular, the folded compact range configuration has been used to perform both highly sensitive coherent change detection (CCD) measurements and interferometric inverse synthetic aperture radar (IFSAR) measurements, which, in addition to the two-dimensional spatial resolution afforded by typical interferometric SAR (ISAR) processing, provides resolution of the relative height of targets with accuracies on the order of a wavelength. This paper describes the development of the folded compact range, as well as the coherent change detection and interferometric measurements that have been made with the system. The measurement have been very successful, and have demonstrated not only the viability of the folded compact range concept in simulating SAR CCD and IFSAR measurements, but also its usefulness as a tool in the research and development of SAR CCD and IFSAR image generation and measurement methodologies.

  12. The Design and First Airborne Experiment of China Imaging Altimeter (CIALT)

    NASA Astrophysics Data System (ADS)

    Zhang, Yunhua; Xu, Ke; Jiang, Jingshan

    average sea level, the significant wave height, and the backscattering coefficient of ocean surface. Sometimes it can also be used for the monitoring and measurment of sea ice. Usually the nadir looking antenna is used for TRA, and in this case it can just obtain one-dimensional height variation along the track. In this paper, we introduce a new-concept imaging radar altimeter, CIALT, which has been proposed more than two years ago. This imaging radar altimeter is aimed for providing three-dimensional surface information of both earth and ocean with high ground and height resolution. This imaging radar altimeter is off-nadir looking operated and in this manner, a wider swath and a higher space resolution in range direction can be obtained. Three techniques are integrated in this imaging radar altimeter, the first one is a robust onboard height tracker, which are based on the off-set center of gravity (OCOG) algorithm and it can work adaptively both for land and ocean surface; The second one is the synthetic processing in the azimuthal direction, in our design both unfocus and focus algorithms are involved in; The third one is the interferometric technique by which pixel-height information can be obtained. In the case of ocean observtion, a more precise ground height tracker is used. It is the height tracker makes our imaging radar altimeter different from the InSAR systems. The average height information output by height tracker is very useful for retrieving the pixel height information in the course of phase unwrapping. system. Some key issues have been addressed. Finally the first airborne experiment campain of CIALT has been introduced. After extensive processing of the experimental raw data, height tracking curves, high space resolution images, and interferometric information have been successfully obtained. They are also presented in this paper.

  13. A comparative evaluation of SAR and SLAR

    SciTech Connect

    Mastin, G.A.; Manson, J.J.; Bradley, J.D.; Axline, R.M.; Hover, G.L.

    1993-11-01

    Synthetic aperture radar (SAR) was evaluated as a potential technological improvement over the Coast Guard`s existing side-looking airborne radar (SLAR) for oil-spill surveillance applications. The US Coast Guard Research and Development Center (R&D Center), Environmental Branch, sponsored a joint experiment including the US Coast Guard, Sandia National Laboratories, and the Naval Oceanographic and Atmospheric Administration (NOAA), Hazardous Materials Division. Radar imaging missions were flown on six days over the coastal waters off Santa Barbara, CA, where there are constant natural seeps of oil. Both the Coast Guard SLAR and the Sandia National Laboratories SAR were employed to acquire simultaneous images of oil slicks and other natural sea surface features that impact oil-spill interpretation. Surface truth and other environmental data were also recorded during the experiment. The experiment data were processed at Sandia National Laboratories and delivered to the R&D Center on a computer workstation for analysis by experiment participants. Issues such as optimal spatial resolution, single-look vs. multi-look SAR imaging, and the utility of SAR for oil-spill analysis were addressed. Finally, conceptual design requirements for a possible future Coast Guard SAR were outlined and evaluated.

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  15. Airborne Transparencies.

    ERIC Educational Resources Information Center

    Horne, Lois Thommason

    1984-01-01

    Starting from a science project on flight, art students discussed and investigated various means of moving in space. Then they made acetate illustrations which could be used as transparencies. The projection phenomenon made the illustrations look airborne. (CS)

  16. Interferometric observation of microlensing events

    NASA Astrophysics Data System (ADS)

    Cassan, Arnaud; Ranc, Clément

    2016-05-01

    Interferometric observations of microlensing events have the potential to provide unique constraints on the physical properties of the lensing systems. In this work, we first present a formalism that closely combines interferometric and microlensing observable quantities, which lead us to define an original microlensing (u, v) plane. We run simulations of long-baseline interferometric observations and photometric light curves to decide which observational strategy is required to obtain a precise measurement on vector Einstein radius. We finally perform a detailed analysis of the expected number of targets in the light of new microlensing surveys (2011+) which currently deliver 2000 alerts per year. We find that a few events are already at reach of long-baseline interferometers (CHARA, VLTI), and a rate of about six events per year is expected with a limiting magnitude of K ≃ 10. This number would increase by an order of magnitude by raising it to K ≃ 11. We thus expect that a new route for characterizing microlensing events will be opened by the upcoming generations of interferometers.

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

    NASA Technical Reports Server (NTRS)

    Mace, Thomas H.; Lou, Yunling

    2009-01-01

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

  18. Polar format algorithm for SAR imaging with Matlab

    NASA Astrophysics Data System (ADS)

    Deming, Ross; Best, Matthew; Farrell, Sean

    2014-06-01

    Due to its computational efficiency, the polar format algorithm (PFA) is considered by many to be the workhorse for airborne synthetic aperture radar (SAR) imaging. PFA is implemented in spatial Fourier space, also known as "K-space", which is a convenient domain for understanding SAR performance metrics, sampling requirements, etc. In this paper the mathematics behind PFA are explained and computed examples are presented, both using simulated data, and experimental airborne radar data from the Air Force Research Laboratory (AFRL) Gotcha Challenge collect. In addition, a simple graphical method is described that can be used to model and predict wavefront curvature artifacts in PFA imagery, which are due to the limited validity of the underlying far-field approximation. The appendix includes Matlab code for computing SAR images using PFA.

  19. Fully polarimetric data from the ARL RailSAR

    NASA Astrophysics Data System (ADS)

    Ranney, Kenneth; Kirose, Getachew; Phelan, Brian; Sherbondy, Kelly

    2016-05-01

    The U.S. Army Research Laboratory (ARL) has recently upgraded the indoor, rail-mounted synthetic aperture radar (SAR) system, RailSAR, to enable collection of large amounts of low-frequency, ultrawideband (UWB) data. Our intent is to provide a research tool that is capable of emulating airborne SAR configuration and associated data collection geometries against surrogate explosive hazard threat deployments. By having such a capability, ARL's facility will afford a more rapid response to the ever changing improvised characteristics associated with explosive hazards today and in the future. Therefore, upgrades to this RailSAR tool to improve functionality and performance are needed to meet the potential rapid response assessments to be carried out. The new, lighter RailSAR cart puts less strain on the radar positioning hardware and allows the system to move smoothly along a specified portion of the rail. In previous papers, we have presented co-polarized SAR data collected using the ARL RailSAR. Recently, however, researchers at ARL have leveraged this asset to collect polarimetric data against multiple targets. This paper presents the SAR imagery resulting from these experiments and documents characteristics of certain target signatures that should be of interest to developers of automatic target detection (ATD) algorithms.

  20. InSAR data for monitoring land subsidence: time to think big

    NASA Astrophysics Data System (ADS)

    Ferretti, A.; Colombo, D.; Fumagalli, A.; Novali, F.; Rucci, A.

    2015-11-01

    Satellite interferometric synthetic aperture radar (InSAR) data have proven effective and valuable in the analysis of urban subsidence phenomena based on multi-temporal radar images. Results obtained by processing data acquired by different radar sensors, have shown the potential of InSAR and highlighted the key points for an operational use of this technology, namely: (1) regular acquisition over large areas of interferometric data stacks; (2) use of advanced processing algorithms, capable of estimating and removing atmospheric disturbances; (3) access to significant processing power for a regular update of the information over large areas. In this paper, we show how the operational potential of InSAR has been realized thanks to the recent advances in InSAR processing algorithms, the advent of cloud computing and the launch of new satellite platforms, specifically designed for InSAR analyses (e.g. Sentinel-1a operated by the ESA and ALOS2 operated by JAXA). The processing of thousands of SAR scenes to cover an entire nation has been performed successfully in Italy in a project financed by the Italian Ministry of the Environment. The challenge for the future is to pass from the historical analysis of SAR scenes already acquired in digital archives to a near real-time monitoring program where up to date deformation data are routinely provided to final users and decision makers.

  1. A Time Domain Along-Track SAR Interferometry Method

    NASA Astrophysics Data System (ADS)

    Cao, N.; Lee, H.; Jung, H. C.

    2015-12-01

    Differential interferometric synthetic aperture radar (DInSAR) has already been proven to be a useful technique for measuring ground displacement at millimeter level. One major drawback of traditional DInSAR technique is that only 1-D deformation in slant range direction can be detected. In order to obtain along-track displacement using a single InSAR pair, two major attempts have been made. The first one is based on cross-correlation between two SAR amplitude images. The second attempt is based on split-beam processing to generate two SAR images from forward- and backward-looking beams. Comparing with the former method, this multiple-aperture SAR interferometry (MAI) can achieve much better measurement accuracy. The major drawback of the MAI method is degraded signal to noise ratio (SNR) and along-track resolution since total along-track integration time decreases in the split-beam procedure. In order to improve the SNR and along-track resolution as well as to extract the terrain displacement in the along-track direction, a time domain along-track SAR interferometry method is proposed in this study. Using traditional time domain backprojection method, the phase component corresponding to slant range direction offset can be estimated and removed from the range compressed SAR signal. Then a phase estimation procedure is implemented to obtain the phase component in the along-track direction. Using ALOS PALSAR data over Kilauea Volcano area in Hawai'i, our experimental results demonstrate the improved performance of the proposed method in extracting 2-D terrain deformation map from one pair of SAR images.

  2. Evaluation of DEM-assisted SAR coregistration

    NASA Astrophysics Data System (ADS)

    Nitti, D. O.; Hanssen, R. F.; Refice, A.; Bovenga, F.; Milillo, G.; Nutricato, R.

    2008-10-01

    Image alignment is without doubt the most crucial step in SAR Interferometry. Interferogram formation requires images to be coregistered with an accuracy of better than 1/8 pixel to avoid significant loss of phase coherence. Conventional interferometric precise coregistration methods for full-resolution SAR data (Single-Look Complex imagery, or SLC) are based on the cross-correlation of the SLC data, either in the original complex form or as squared amplitudes. Offset vectors in slant range and azimuth directions are computed on a large number of windows, according to the estimated correlation peaks. Then, a two-dimensional polynomial of a certain degree is usually chosen as warp function and the polynomial parameters are estimated through LMS fit from the shifts measured on the image windows. In case of rough topography and long baselines, the polynomial approximation for the warp function becomes inaccurate, leading to local misregistrations. Moreover, these effects increase with the spatial resolution and then with the sampling frequency of the sensor, as first results on TerraSAR-X interferometry confirm. An improved, DEM-assisted image coregistration procedure can be adopted for providing higher-order prediction of the offset vectors. Instead of estimating the shifts on a limited number of patches and using a polynomial approximation for the transformation, this approach computes pixel by pixel the correspondence between master and slave by using the orbital data and a reference DEM. This study assesses the performance of this approach with respect to the standard procedure. In particular, both analytical relationships and simulations will evaluate the impact of the finite vertical accuracy of the DEM on the final coregistration precision for different radar postings and relative positions of satellites. The two approaches are compared by processing real data at different carrier frequencies and using the interferometric coherence as quality figure.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  4. DInSAR fringes simulation of sandbox models

    NASA Astrophysics Data System (ADS)

    Derron, Marc-Henri; Carrea, Dario; Michoud, Clément; Jaboyedoff, Michel

    2015-04-01

    Interpreting satellite DInSAR patterns of slope movements can be difficult because of unwrapping problems, loss of coherence or radar imaging geometry limitations (layover, shadowing …). We investigate the potential of simulating interferometric fringes as a tool to help understanding real DInSAR images. Various types of gravitational slope deformations (sliding, toppling …) have been produced in a sandbox in the lab. These experiments were monitored with a micro-lidar Minolta-Konika Vivid 9i to get successive Digital Elevation Models of the surface. A pair of DEM is then used to simulate DInSAR fringes patterns, with the possibility to vary the wavelength, the angle between the line of sight and the ground displacement, the look angle, the baseline, etc. DInSAR fringes simulated here are idealized. They are not affected by any noise, decoherence, layover or shadow effects; radar image deformations are computed in ancillary files. However it appears that even these ideal wrapped fringes patterns get rapidly very complex when deformation is strong. Then this kind of tool is of interest to better constrain ground surface deformations from resulting InSAR fringes (from lab models or real landslides data). It makes also possible to test how the acquisition geometry impacts the InSAR result depending on the type of slope movement considered.

  5. Methods of InSAR atmosphere correction for volcano activity monitoring

    USGS Publications Warehouse

    Gong, W.; Meyer, F.; Webley, P.W.; Lu, Zhiming

    2011-01-01

    When a Synthetic Aperture Radar (SAR) signal propagates through the atmosphere on its path to and from the sensor, it is inevitably affected by atmospheric effects. In particular, the applicability and accuracy of Interferometric SAR (InSAR) techniques for volcano monitoring is limited by atmospheric path delays. Therefore, atmospheric correction of interferograms is required to improve the performance of InSAR for detecting volcanic activity, especially in order to advance its ability to detect subtle pre-eruptive changes in deformation dynamics. In this paper, we focus on InSAR tropospheric mitigation methods and their performance in volcano deformation monitoring. Our study areas include Okmok volcano and Unimak Island located in the eastern Aleutians, AK. We explore two methods to mitigate atmospheric artifacts, namely the numerical weather model simulation and the atmospheric filtering using Persistent Scatterer processing. We investigate the capability of the proposed methods, and investigate their limitations and advantages when applied to determine volcanic processes. ?? 2011 IEEE.

  6. Ground settlement monitoring from temporarily persistent scatterers between two SAR acquisitions

    USGS Publications Warehouse

    Lei, Z.; Xiaoli, D.; Guangcai, F.; Zhong, L.

    2009-01-01

    We present an improved differential interferometric synthetic aperture radar (DInSAR) analysis method that measures motions of scatterers whose phases are stable between two SAR acquisitions. Such scatterers are referred to as temporarily persistent scatterers (TPS) for simplicity. Unlike the persistent scatterer InSAR (PS-InSAR) method that relies on a time-series of interferograms, the new algorithm needs only one interferogram. TPS are identified based on pixel offsets between two SAR images, and are specially coregistered based on their estimated offsets instead of a global polynomial for the whole image. Phase unwrapping is carried out based on an algorithm for sparse data points. The method is successfully applied to measure the settlement in the Hong Kong Airport area. The buildings surrounded by vegetation were successfully selected as TPS and the tiny deformation signal over the area was detected. ??2009 IEEE.

  7. SAR Remote Sensing for Urban Building Earthquake-Damage Detection and Assessment: A Review

    NASA Astrophysics Data System (ADS)

    Gong, Lixia; Wu, Fan; Zhang, Jingfa; Li, Rong

    2014-11-01

    Urban building damage detection and assessment after earthquake is crucial for effective post disaster relief actions. Synthetic Aperture Radar (SAR) is a key sensor to provide vital information due to its ability to map the affected areas independently of weather conditions, day and night. Under the condition of medium resolution SAR image, change detection is usually applied to identify damaged building by comparing post-seismic to pre-seismic images based on the intensity correlation and interferometric coherence. However, the new high resolution on-orbit SAR sensors (e.g. Radarsat-2, TerraSAR-X/ TanDEM-X, COSMO-SkyMed etc.) have renewed interest in extraction information for monitoring the damage. Intensity, phase and polarimetric information are usually adopted for the damage detection and assessment. The present paper reviews the theoretical background and applications of SAR remote sensing techniques to the study of urban building damage detection and assessment by earthquake.

  8. SAR change detection MTI

    NASA Astrophysics Data System (ADS)

    Scarborough, Steven; Lemanski, Christopher; Nichols, Howard; Owirka, Gregory; Minardi, Michael; Hale, Todd

    2006-05-01

    This paper examines the theory, application, and results of using single-channel synthetic aperture radar (SAR) data with Moving Reference Processing (MRP) to focus and geolocate moving targets. Moving targets within a standard SAR imaging scene are defocused, displaced, or completely missing in the final image. Building on previous research at AFRL, the SAR-MRP method focuses and geolocates moving targets by reprocessing the SAR data to focus the movers rather than the stationary clutter. SAR change detection is used so that target detection and focusing is performed more robustly. In the cases where moving target returns possess the same range versus slow-time histories, a geolocation ambiguity results. This ambiguity can be resolved in a number of ways. This paper concludes by applying the SAR-MRP method to high-frequency radar measurements from persistent continuous-dwell SAR observations of a moving target.

  9. A dense medium electromagnetic scattering model for the InSAR correlation of snow

    NASA Astrophysics Data System (ADS)

    Lei, Yang; Siqueira, Paul; Treuhaft, Robert

    2016-05-01

    Snow characteristics, such as snow water equivalent (SWE) and snow grain size, are important characteristics for the monitoring of the global hydrological cycle and as indicators of climate change. This paper derives an interferometric synthetic aperture radar (InSAR) scattering model for dense media, such as snow, which takes into account multiple scattering effects through the Quasi-Crystalline Approximation. The result of this derivation is a simplified version of the InSAR correlation model derived for relating the InSAR correlation measurements to the snowpack characteristics of grain size, volume fraction, and layer depth as well as those aspects of the volume-ground interaction that affects the interferometric observation (i.e., the surface topography and the ratio of ground-to-volume scattering). Based on the model, the sensitivity of the InSAR correlation measurements to the snow characteristics is explored by simulation. Through this process, it is shown that Ka-band InSAR phase has a good sensitivity to snow grain size and volume fraction, while for lower frequency signals (Ku-band to L-band), the InSAR correlation magnitude and phase have a sensitivity to snow depth. Since the formulation depends, in part, on the pair distribution function, three functional forms of the pair distribution function are implemented and their effects on InSAR phase measurements compared. The InSAR scattering model described in this paper is intended to be an observational prototype for future Ka-band and L-band InSAR missions, such as NASA's Surface Water and Ocean Topography and NASA-ISRO Synthetic Aperture Radar missions, planned for launch in the 2020-2021 time frame. This formulation also enables further investigation of the InSAR-based snow retrieval approaches.

  10. The InSAR Scientific Computing Environment

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    We have developed a flexible and extensible Interferometric SAR (InSAR) Scientific Computing Environment (ISCE) for geodetic image processing. ISCE was designed from the ground up as a geophysics community tool for generating stacks of interferograms that lend themselves to various forms of time-series analysis, with attention paid to accuracy, extensibility, and modularity. The framework is python-based, with code elements rigorously componentized by separating input/output operations from the processing engines. This allows greater flexibility and extensibility in the data models, and creates algorithmic code that is less susceptible to unnecessary modification when new data types and sensors are available. In addition, the components support provenance and checkpointing to facilitate reprocessing and algorithm exploration. The algorithms, based on legacy processing codes, have been adapted to assume a common reference track approach for all images acquired from nearby orbits, simplifying and systematizing the geometry for time-series analysis. The framework is designed to easily allow user contributions, and is distributed for free use by researchers. ISCE can process data from the ALOS, ERS, EnviSAT, Cosmo-SkyMed, RadarSAT-1, RadarSAT-2, and TerraSAR-X platforms, starting from Level-0 or Level 1 as provided from the data source, and going as far as Level 3 geocoded deformation products. With its flexible design, it can be extended with raw/meta data parsers to enable it to work with radar data from other platforms

  11. Quantification of L-band InSAR coherence over volcanic areas using LiDAR and in situ measurements

    NASA Astrophysics Data System (ADS)

    Arab-Sedze, Melanie; Heggy, Essam; Bretard, Frederic; Berveiller, Daniel; Jacquemoud, Stephane

    2014-07-01

    Interferometric Synthetic Aperture Radar (InSAR) is a powerful tool to monitor large-scale ground deformation at active volcanoes. However, vegetation and pyroclastic deposits degrade the radar coherence and therefore the measurement of 3-D surface displacements. In this article, we explore the complementarity between ALOS - PALSAR coherence images, airborne LiDAR data and in situ measurements acquired over the Piton de La Fournaise volcano (Reunion Island, France) to determine the sources of errors that may affect repeat-pass InSAR measure- ments. We investigate three types of surfaces: terrains covered with vegetation, lava flows (a'a, pahoehoe or slabby pahoehoe lava flows) and pyroclastic deposits (lapilli). To explain the loss of coherence observed over the Dolomieu crater between 2008 and 2009, we first use laser altimetry data to map topographic variations. The LiDAR intensity, which depends on surface reflectance, also provides ancillary information about the potential sources of coherence loss. In addition, surface roughness and rock dielectric properties of each terrain have been determined in situ to better understand how electromagnetic waves interact with such media: rough and porous surfaces, such as the a'a lava flows, produce a higher coherence loss than smoother surfaces, such as the pahoehoe lava flows. Variations in dielectric properties suggest a higher penetration depth in pyroclasts than in lava flows at L-band frequency. Decorrelation over the lapilli is hence mainly caused by volumetric effects. Finally, a map of LAI (Leaf Area Index) produced using SPOT 5 imagery allows us to quantify the effect of vegeta- tion density: radar coherence is negatively correlated with LAI and is unreliable for values higher than 7.5.

  12. Interferometric Processing of SLC Sentinel-1 TOPS Data

    NASA Astrophysics Data System (ADS)

    Grandin, Raphael

    2015-05-01

    InSAR processing usually involves two successive steps: focusing and interferometry. Most public-domain InSAR processing toolboxes are capable of performing both operations with data acquired in the standard Stripmap mode, starting from raw SAR data (level 0). However, the focusing of burst-mode data, such as TOPS and ScanSAR, requires substantial modifications to standard focusing methods due to the particular spectral properties of these data. Anticipating on this potential difficulty for non-expert users, the European Space Agency has chosen to release Sentinel-1 TOPS data in a Single Look Complex format (level 1). The data are already focused using state-of-the-art processing techniques, with phase information preserved. Even so, the focusing method introduces an additional quadratic phase term in the azimuth direction. In case of a small misregistration error between a pair of images, this residual term leads to steep phase ramps in azimuth that are superimposed on the desired interferometric phase. Therefore, this quadratic phase term needs to be removed from the SLC data prior to interferogram calculation. Here, a pre-processing method allowing for compensating this phase term and simply feeding the corrected SLC data into a standard InSAR processing chain is described. The method consists of three steps. The first step uses the metadata in order to reconstruct a continuous image in the azimuth direction, accounting for the small overlap between adjacent bursts (“stitching”). In the second step, multiplication of the images by an appropriate phase screen is performed so as to cancel the azimuthal quadratic phase term (“deramping”). The deramping operation uses the metadata, as well as the azimuth time lag between the images deduced from sub-pixel image correlation, in order to determine small misregistration errors. Misregistration errors are compensated using a simple affine relation deduced from least-square fitting of the azimuth offsets

  13. Frequency modulated lasers for interferometric optical gyroscopes.

    PubMed

    Komljenovic, Tin; Tran, Minh A; Belt, Michael; Gundavarapu, Sarat; Blumenthal, Daniel J; Bowers, John E

    2016-04-15

    We study the use of frequency modulated lasers in interferometric optical gyroscopes and show that by exploiting various frequency modulation signals, the laser coherence can be controlled. We show that both angle random walk and bias stability of an interferometric optical gyroscope based on laser sources can be improved with this technique. PMID:27082342

  14. Oil spill experiment using airborne DLR ESAR off the coast of Diu, India.

    PubMed

    Sasamal, S K; Rao, M V

    2015-05-15

    Oil spill experiment results in the coastal waters of Diu, India, with an airborne DLR ESAR sensor are discussed with reference to the SAR frequency, polarization and viewing angle. The SAR data acquired in the quad polarization of the L band and dual polarization of the C band over two spills are studied. A higher oil and water contrast is observed in the L-VV polarization than in the C-HH mode. Oil spill discrimination is possible over a wider view angle of the airborne SAR sensor data in L band than in C band. This study has also analyzed the spread and drift of oil in coastal waters.

  15. Airborne Imagery

    NASA Technical Reports Server (NTRS)

    1983-01-01

    ATM (Airborne Thematic Mapper) was developed for NSTL (National Space Technology Companies) by Daedalus Company. It offers expanded capabilities for timely, accurate and cost effective identification of areas with prospecting potential. A related system is TIMS, Thermal Infrared Multispectral Scanner. Originating from Landsat 4, it is also used for agricultural studies, etc.

  16. Synthetic aperture radar speckle reduction for circle mode SAR images

    NASA Astrophysics Data System (ADS)

    Musgrove, Cameron

    2016-05-01

    Synthetic aperture radar (SAR) images contain a grainy pattern, called speckle, that is a consequence of a coherent imaging system. For fine resolution SAR images speckle can obscure subtle features and reduce visual appeal. Many speckle reduction methods result in a loss of image resolution and reduce visual appeal which can obscure subtle features. Another approach to maintain resolution while reducing speckle is to register and combine multiple images. For persistent surveillance applications it is more efficient for an airborne platform to fly circles around the particular area of interest. In these cases, it would be beneficial to combine multiple circle mode SAR images, however the image registration process is not so straightforward because the layover angle changes in each image. This paper develops a SAR image registration process for combining multiple circle mode SAR images to reduce speckle while preserving resolution. The registration first uses a feature matching algorithm for a coarse rotation and alignment, and then uses a fine registration and warp. Ku band SAR data from a circle mode SAR collection is used to show the effectiveness of the registration and enhanced visual appeal from multi-looking.

  17. Vegetation profiles in tropical forests from multibaseline interferometric synthetic aperture radar, field, and lidar measurements

    NASA Astrophysics Data System (ADS)

    Treuhaft, R. N.; Chapman, B. D.; Dos Santos, J. R.; GonçAlves, F. G.; Dutra, L. V.; GraçA, P. M. L. A.; Drake, J. B.

    2009-12-01

    This paper addresses the estimation of vertical vegetation density profiles from multibaseline interferometric synthetic aperture radar (InSAR) data from the AirSAR aircraft at C band over primary, secondary, and abandoned-pasture stands at La Selva Biological Station, Costa Rica in 2004. Profiles were also estimated from field data taken in 2006 and lidar data taken with the LVIS, 25 m spot instrument in 2005. After motivating the study of tropical forest profiles based on their role in the global carbon cycle, ecosystem state, and biodiversity, this paper describes the InSAR, field, and lidar data acquisitions and analyses. Beyond qualitative agreement between profiles from the 3 measurement techniques, results show that InSAR and lidar profile-averaged mean height have RMS scatters about field-measured means of 3.4 m and 3.2 m, 16% and 15% of the average mean height, respectively. InSAR and lidar standard deviations of the vegetation distribution have RMS scatters about the field standard deviations of 1.9 m and 1.5 m, or 27% and 21%, respectively. Dominant errors in the profile-averaged mean height for each measurement technique were modeled. InSAR inaccuracies, dominated by ambiguities in finding the ground altitude and coherence calibration, together account for about 3 m of InSAR error in the mean height. The dominant, modeled error for the field measurements was the inaccuracy in modeling the trees as uniformly filled volumes of leaf area, inducing field errors in mean height of about 3 m. The dominant, modeled lidar error, also due to finding the ground, was 2 m.

  18. Real time SAR processing

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  19. Mapping ground surface deformation using temporarily coherent point SAR interferometry: Application to Los Angeles Basin

    USGS Publications Warehouse

    Zhang, L.; Lu, Zhiming; Ding, X.; Jung, H.-S.; Feng, G.; Lee, C.-W.

    2012-01-01

    Multi-temporal interferometric synthetic aperture radar (InSAR) is an effective tool to detect long-term seismotectonic motions by reducing the atmospheric artifacts, thereby providing more precise deformation signal. The commonly used approaches such as persistent scatterer InSAR (PSInSAR) and small baseline subset (SBAS) algorithms need to resolve the phase ambiguities in interferogram stacks either by searching a predefined solution space or by sparse phase unwrapping methods; however the efficiency and the success of phase unwrapping cannot be guaranteed. We present here an alternative approach - temporarily coherent point (TCP) InSAR (TCPInSAR) - to estimate the long term deformation rate without the need of phase unwrapping. The proposed approach has a series of innovations including TCP identification, TCP network and TCP least squares estimator. We apply the proposed method to the Los Angeles Basin in southern California where structurally active faults are believed capable of generating damaging earthquakes. The analysis is based on 55 interferograms from 32 ERS-1/2 images acquired during Oct. 1995 and Dec. 2000. To evaluate the performance of TCPInSAR on a small set of observations, a test with half of interferometric pairs is also performed. The retrieved TCPInSAR measurements have been validated by a comparison with GPS observations from Southern California Integrated GPS Network. Our result presents a similar deformation pattern as shown in past InSAR studies but with a smaller average standard deviation (4.6. mm) compared with GPS observations, indicating that TCPInSAR is a promising alternative for efficiently mapping ground deformation even from a relatively smaller set of interferograms. ?? 2011.

  20. Detection of land degradation with polarimetric SAR

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  1. Software For Calibration Of Polarimetric SAR Data

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  2. Atmospheric Effects on InSAR Measurements and Their Mitigation

    PubMed Central

    Ding, Xiao-li; Li, Zhi-wei; Zhu, Jian-jun; Feng, Guang-cai; Long, Jiang-ping

    2008-01-01

    Interferometric Synthetic Aperture Radar (InSAR) is a powerful technology for observing the Earth surface, especially for mapping the Earth's topography and deformations. InSAR measurements are however often significantly affected by the atmosphere as the radar signals propagate through the atmosphere whose state varies both in space and in time. Great efforts have been made in recent years to better understand the properties of the atmospheric effects and to develop methods for mitigating the effects. This paper provides a systematic review of the work carried out in this area. The basic principles of atmospheric effects on repeat-pass InSAR are first introduced. The studies on the properties of the atmospheric effects, including the magnitudes of the effects determined in the various parts of the world, the spectra of the atmospheric effects, the isotropic properties and the statistical distributions of the effects, are then discussed. The various methods developed for mitigating the atmospheric effects are then reviewed, including the methods that are based on PSInSAR processing, the methods that are based on interferogram modeling, and those that are based on external data such as GPS observations, ground meteorological data, and satellite data including those from the MODIS and MERIS. Two examples that use MODIS and MERIS data respectively to calibrate atmospheric effects on InSAR are also given.

  3. High-Level Performance Modeling of SAR Systems

    NASA Technical Reports Server (NTRS)

    Chen, Curtis

    2006-01-01

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

  4. Detecting and monitoring UCG subsidence with InSAR

    SciTech Connect

    Mellors, R J; Foxall, W; Yang, X

    2012-03-23

    The use of interferometric synthetic aperture radar (InSAR) to measure surface subsidence caused by Underground Coal Gasification (UCG) is tested. InSAR is a remote sensing technique that uses Synthetic Aperture Radar images to make spatial images of surface deformation and may be deployed from satellite or an airplane. With current commercial satellite data, the technique works best in areas with little vegetation or farming activity. UCG subsidence is generally caused by roof collapse, which adversely affects UCG operations due to gas loss and is therefore important to monitor. Previous studies have demonstrated the usefulness of InSAR in measuring surface subsidence related to coal mining and surface deformation caused by a coal mining roof collapse in Crandall Canyon, Utah is imaged as a proof-of-concept. InSAR data is collected and processed over three known UCG operations including two pilot plants (Majuba, South Africa and Wulanchabu, China) and an operational plant (Angren, Uzbekistan). A clear f eature showing approximately 7 cm of subsidence is observed in the UCG field in Angren. Subsidence is not observed in the other two areas, which produce from deeper coal seams and processed a smaller volume. The results show that in some cases, InSAR is a useful tool to image UCG related subsidence. Data from newer satellites and improved algorithms will improve effectiveness.

  5. Source Detection with Interferometric Datasets

    NASA Astrophysics Data System (ADS)

    Trott, Cathryn M.; Wayth, Randall B.; Macquart, Jean-Pierre R.; Tingay, Steven J.

    2012-04-01

    The detection of sources in interferometric radio data typically relies on extracting information from images, formed by Fourier transform of the underlying visibility dataset, and CLEANed of contaminating sidelobes through iterative deconvolution. Variable and transient radio sources span a large range of variability timescales, and their study has the potential to enhance our knowledge of the dynamic universe. Their detection and classification involve large data rates and non-stationary PSFs, commensal observing programs and ambitious science goals, and will demand a paradigm shift in the deployment of next-generation instruments. Optimal source detection and classification in real time requires efficient and automated algorithms. On short time-scales variability can be probed with an optimal matched filter detector applied directly to the visibility dataset. This paper shows the design of such a detector, and some preliminary detection performance results.

  6. Interferometric imaging of geostationary satellites

    NASA Astrophysics Data System (ADS)

    Armstrong, J. T.; Baines, E. K.; Hindsley, R. B.; Schmitt, H. R.; Restaino, S. R.; Jorgensen, A. M.; Mozurkewich, D.

    2012-06-01

    Even the longest geosatellite, at 40 m, subtends only 0.2 arcsec (1 microradian). Determining structure and orientation with 10 cm resolution requires a 90 m telescope at visual wavelengths, or an interferometer. We de- scribe the application of optical interferometry to observations of complex extended targets such as geosatellites, and discuss some of its challenges. We brie y describe our Navy Optical Interferometer (NOI) group's eorts toward interferometric observations of geosatellites, including the rst interferometric detection of a geosatellite. The NOI observes in 16 spectral channels (550{850 nm) using up to six 12-cm apertures, with baselines (separa- tions between apertures) of 16 to 79 m. We detected the geosatellite DirecTV-9S during glint seasons in March 2008 and March 2009, using a single 16 m baseline (resolution 1:6 m). Fringes on a longer baseline were too weak because the large-scale structure was over-resolved. The fringe strengths are consistent with a combination of two size scales, 1:3 m and & 3:5 m. Our near term NOI work is directed toward observing geosatellites with three or more 10 to 15 m baselines, using closure phase measurements to remove atmospheric turbulence eects and coherent data averaging to increase the SNR. Beyond the two- to three-year time frame, we plan to install larger apertures (1.4 and 1.8 m), allowing observations outside glint season, and to develop baseline bootstrap- ping, building long baselines from chains of short baselines, to avoid over-resolution while increasing maximum resolution. Our ultimate goal is to develop the design parameters for dedicated satellite imaging interferometry.

  7. Design of a monopulse SAR system to determine elevation angles

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    Terrain height variations in mountainous areas cause problems in radiometric corrections of synthetic aperture radar (SAR) images. To determine the elevation angle and the height at the different parts of an image, an application of the monopulse principle is proposed. From the ratios of images radiometrically modulated by the difference and sum antenna pattern in range it is possible to calculate the appropriate elevation angle at any point in the image. Design considerations for a corresponding airborne SAR-system are presented, and some estimates of error influences (e.g., ambiguities), expected performance and precision in topographic mapping are given.

  8. Lithologic mapping in a sedimentary environment using multipolarization SAR images

    NASA Technical Reports Server (NTRS)

    Evans, D. L.; Schenck, L. R.

    1985-01-01

    Multipolarization Synthetic Aperture Radar (SAR) data from the NASA/JPL aircraft SAR were used in conjunction with LANDSAT Thematic Mapper (TM), Thermal Infrared Multispectral Scanner (TIMS), and Airborne Imaging Spectrometer (AIS) data as part of a three-year research program to evaluate the utility of remote sensing measurements for analysis of sedimentary basins. The purpose of this research effort is to construct stratigraphic columns, map variations in the lithology, geometry, and structure of sedimentary rocks in the Wind River/Bighorn Basin area, Wyoming, and to integrate remote sensing data with conventional rain models of basin formation and evolution.

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  10. Magma flux at Okmok Volcano, Alaska, from a joint inversion of continuous GPS, campaign GPS, and interferometric synthetic aperture radar

    NASA Astrophysics Data System (ADS)

    Biggs, Juliet; Lu, Zhong; Fournier, Tom; Freymueller, Jeffrey T.

    2010-12-01

    Volcano deformation is usually measured using satellite geodetic techniques including interferometric synthetic aperture radar (InSAR), campaign GPS, and continuous GPS. Differences in the spatial and temporal sampling of each system mean that most appropriate inversion scheme to determine the source parameters from each data set is different. Most studies either compare results from independent inversions or subsample the data sets to the lowest common factor. It is unclear whether differences in the solution reflect differences in source behavior, differences in measurement bias, or differences in inversion technique. Here we develop a single inversion procedure that captures the benefits of each system, especially the daily sampling of continuous GPS and the high spatial resolution of InSAR. Okmok Volcano, Alaska, is an ideal target for such a test because a long series (<15 years) of InSAR and continuous GPS measurement exists and the source is almost continuously active and in a stable location.

  11. Apply Multi-baseline SAR Interferometry on Long Term Space-borne SAR Data for 3-D Reconstruction in Forest and Urban Areas

    NASA Astrophysics Data System (ADS)

    Lin, Q.; Zebker, H. A.

    2014-12-01

    Multi Baseline Synthetic Aperture Radar (MB SAR) Tomography is a promising extension to traditional SAR interferometry. By coherently combining SAR images acquired from different baseline location, MB SAR Tomography can achieve unprecedentedly full 3-D imaging of volumetric and layover scatters for each SAR cell.Its capability of 3-D reflectivity reconstruction and multiple scatters separation is enormously helpful for different scientific applications in forestry, agriculture , glaciology etc. However, in order to apply on repeat-pass space borne interferometric dataset, the Fourier Based MB SAR Tomography is generally affected by unsatisfactory imaging quality due to low number of baseline with unequal distribution, atmospheric phase disturbance and temporal decorrelation. In this paper, we propose different signal processing techniques for overcoming these limitations in oder for a better image quality. 1) we develop a robust interpolator to translate the nonuniform greed to uniform one, largely improved the image quality 2) we apply Robust Capon Spectrum Estimation method to improve the resolution and interference of uncertainty in steering matrix. 3) for atmosphere disturbance and radiometric , we select certain flat and known area from image as a estimation for atmospheric offset. We first test our result in simulated SAR data. Comparing with Fourier based method, the result shows better sidelobe suppression and robustness to unknown multiplicative phase noise. Finally, we test the algorithm using real ALOS PALSAR L-band data, acquired between August 2009 to February 2011 near Harvard Forest Area, MA, USA.

  12. Helmand river hydrologic studies using ALOS PALSAR InSAR and ENVISAT altimetry

    USGS Publications Warehouse

    Lu, Zhiming; Kim, J.-W.; Lee, H.; Shum, C.K.; Duan, J.; Ibaraki, M.; Akyilmaz, O.; Read, C.-H.

    2009-01-01

    The Helmand River wetland represents the only fresh-water resource in southern Afghanistan and one of the least mapped water basins in the world. The relatively narrow wetland consists of mostly marshes surrounded by dry lands. In this study, we demonstrate the use of the Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) Interferometric SAR (InSAR) to detect the changes of the Helmand River wetland water level. InSAR images are combined with the geocentric water level measurements from the retracked high-rate (18-Hz) Environmental Satellite (Envisat) radar altimetry to construct absolute water level changes over the marshes. It is demonstrated that the integration of the altimeter and InSAR can provide spatio-temporal measurements of water level variation over the Helmand River marshes where in situ measurements are absent. ?? Taylor & Francis Group, LLC.

  13. Multistage processing for automatic minefield detection using low-frequency SAR

    NASA Astrophysics Data System (ADS)

    Crocker, Sandra C.; Ayasli, Serpil; Grosch, Theodore O.

    1995-06-01

    An automatic, multistage algorithm for detecting minefields is introduced. This algorithm was tested, with encouraging results, against buried metal mines. The measurement data for this test were obtained using a low-frequency airborne SAR, collected during an extensive ground penetration experiment in Yuma, Arizona, in June 1993. Although verified using SAR data, the automatic minefield detection technique may prove applicable to other remote sensors as well.

  14. Generalized ISAR--part II: interferometric techniques for three-dimensional location of scatterers.

    PubMed

    Given, James A; Schmidt, William R

    2005-11-01

    This paper is the second part of a study dedicated to optimizing diagnostic inverse synthetic aperture radar (ISAR) studies of large naval vessels. The method developed here provides accurate determination of the position of important radio-frequency scatterers by combining accurate knowledge of ship position and orientation with specialized signal processing. The method allows for the simultaneous presence of substantial Doppler returns from both change of roll angle and change of aspect angle by introducing generalized ISAR ates. The first paper provides two modes of interpreting ISAR plots, one valid when roll Doppler is dominant, the other valid when the aspect angle Doppler is dominant. Here, we provide, for each type of ISAR plot technique, a corresponding interferometric ISAR (InSAR) technique. The former, aspect-angle dominated InSAR, is a generalization of standard InSAR; the latter, roll-angle dominated InSAR, seems to be new to this work. Both methods are shown to be efficient at identifying localized scatterers under simulation conditions. PMID:16279180

  15. Generalized ISAR--part II: interferometric techniques for three-dimensional location of scatterers.

    PubMed

    Given, James A; Schmidt, William R

    2005-11-01

    This paper is the second part of a study dedicated to optimizing diagnostic inverse synthetic aperture radar (ISAR) studies of large naval vessels. The method developed here provides accurate determination of the position of important radio-frequency scatterers by combining accurate knowledge of ship position and orientation with specialized signal processing. The method allows for the simultaneous presence of substantial Doppler returns from both change of roll angle and change of aspect angle by introducing generalized ISAR ates. The first paper provides two modes of interpreting ISAR plots, one valid when roll Doppler is dominant, the other valid when the aspect angle Doppler is dominant. Here, we provide, for each type of ISAR plot technique, a corresponding interferometric ISAR (InSAR) technique. The former, aspect-angle dominated InSAR, is a generalization of standard InSAR; the latter, roll-angle dominated InSAR, seems to be new to this work. Both methods are shown to be efficient at identifying localized scatterers under simulation conditions.

  16. 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.

  17. Monitoring and analyzing surface subsidence based on SBAS-InSAR in Beijing region, China

    NASA Astrophysics Data System (ADS)

    Zhou, L.; Guo, J. M.; Li, X.

    2015-12-01

    Surface subsidence is the main regional environmental geological disaster in plain area in China. The rapid growth of population, the over-exploitation of groundwater and the rapid development of urbanization impacts the occurrence and development of surface subsidence to some extent. The city of Beijing, located in the Beijing Plain, is one of international metropolis in China that experiences the severe surface subsidence. Because of conventional measurement methods with low spatial resolution, differential interferometric synthetic aperture radar(D-InSAR) is susceptible to signal decorrelation and atmospheric delay, persistent scatterer interferometric synthetic aperture radar(PS-InSAR) is based on a large number of SAR images, but small baseline subset interferometric synthetic aperture radar (SBASInSAR) only needs a small number of images and performs better than PS-InSAR for obtaining nonlinear deformation information, in this paper, SBAS-InSAR was used to obtain the high resolution surface subsidence information in Beijing region, China. A spatial-temporal analysis of the surface subsidence in Beijing region during the years of 2007- 2010 was performed utilizing eighteen C-band ENVISAT ASAR images (from August 1, 2007 to September 29, 2010). The results show that subsidence in Beijing region is severe uneven, subsidence funnels appear in Changping District, Shunyi District, Tongzhou District, Daxing District, etc., and many subsidence funnels are interconnected and have an eastward expansion trend; during the period of 2007 to 2010, the subsidence velocities are in the range of -158.5 mm/year to 12.4 mm/year and the maximum subsidence of subsidence center is over 400 mm; surface subsidence is influenced by groundwater exploitation and urbanization significantly.

  18. First Results From the GeoSAR Mapping Instrument

    NASA Technical Reports Server (NTRS)

    Hensley, Scott; Wheeler, Kevin; Berkun, Andy; Brown, Walt; Chapin, Elaine; Freedman, Adam; Hamilton, Gary; Kroger, Peter; Michel, Charles Le. Thierry; Moller, Delwyn

    1999-01-01

    Geosynchronous Synthetic Aperture Radar (GeoSAR) is a consortium project consisting of The Jet Propulsion Laboratory (JPL), Calgis (a small GIS company based in Fresno, CA) and the California Department of Conservation with funding provided by Defense Research Projects Agency (DARPA) started in November 1996. The two main objectives of the GeoSAR Program are: 1) To develop a state of the art dual frequency interferometric radar mapping instrument capable of mapping the true ground surface height beneath the vegetation canopy; and 2) To transition this mapping technology to a commercial company, Calgis. JPL, the technical lead, has the following program deliverables at program completion in November 1999 include radar design and radar hardware for X-band (3 cm) and P-band (83 cm) radars, processor software, hardware and documentation, and calibrated X-band radar.

  19. Rapid subsidence over oil fields measured by SAR

    NASA Technical Reports Server (NTRS)

    Fielding, E. J.; Blom, R. G.; Goldstein, R. M.

    1998-01-01

    The Lost Hills and Belridge oil felds are in the San Joaquin Valley, California. The major oil reservoir is high porosity and low permeability diatomite. Extraction of large volumes from shallow depths causes reduction in pore pressure and subsequent compaction, forming a surface subsidence bowl. We measure this subsidence from space using interferometric analysis of SAR (Synthetic Aperture Radar) data collected by the European Space Agency Remote Sensing Satellites (ERS-1 and ERS-2). Maximum subsidence rates are as high as 40 mm in 35 days or > 400 mm/yr, measured from interferograms with time separations ranging from one day to 26 months. The 8- and 26-month interferograms contain areas where the subsidence gradient exceeds the measurement possible with ERS SAR, but shows increased detail in areas of less rapid subsidence. Synoptic mapping of subsidence distribution from satellite data powerfully complements ground-based techniques, permits measurements where access is difficult, and aids identification of underlying causes.

  20. Rapid subsidence over oil fields measured by SAR interferometry

    NASA Astrophysics Data System (ADS)

    Fielding, Eric J.; Blom, Ronald G.; Goldstein, Richard M.

    The Lost Hills and Belridge oilfields are in the San Joaquin Valley, California. The major oil reservoir is high porosity and low permeability diatomite. Extraction of large volumes from shallow depths causes reduction in pore pressure and subsequent compaction, forming a surface subsidence bowl. We measure this subsidence from space using interferometric analysis of SAR (Synthetic Aperture Radar) data collected by the European Space Agency Remote Sensing Satellites (ERS-1 and ERS-2). Maximum subsidence rates are as high as 40 mm in 35 days or >400 mm/yr, measured from interferograms with time separations ranging from one day to 26 months. The 8- and 26-month interferograms contain areas where the subsidence gradient exceeds the measurement possible with ERS SAR, but shows increased detail in areas of less rapid subsidence. Synoptic mapping of subsidence distribution from satellite data powerfully complements ground-based techniques, permits measurements where access is difficult, and aids identification of underlying causes.

  1. Mitigation of tropospheric InSAR phase artifacts through differential multisquint processing

    NASA Technical Reports Server (NTRS)

    Chen, Curtis W.

    2004-01-01

    We propose a technique for mitigating tropospheric phase errors in repeat-pass interferometric synthetic aperture radar (InSAR). The mitigation technique is based upon the acquisition of multisquint InSAR data. On each satellite pass over a target area, the radar instrument will acquire images from multiple squint (azimuth) angles, from which multiple interferograms can be formed. The diversity of viewing angles associated with the multisquint acquisition can be used to solve for two components of the 3-D surface displacement vector as well as for the differential tropospheric phase. We describe a model for the performance of the multisquint technique, and we present an assessment of the performance expected.

  2. Assessment of pingo distribution and morphometry using an IfSAR derived digital surface model, western Arctic Coastal Plain, Northern Alaska

    USGS Publications Warehouse

    Jones, Benjamin M.; Grosse, G.; Hinkel, Kenneth M.; Arp, C.D.; Walker, S.; Beck, R.A.; Galloway, J.P.

    2012-01-01

    Pingos are circular to elongate ice-cored mounds that form by injection and freezing of pressurized water in near-surface permafrost. Here we use a digital surface model (DSM) derived from an airborne Interferometric Synthetic Aperture Radar (IfSAR) system to assess the distribution and morphometry of pingos within a 40,000km2 area on the western Arctic Coastal Plain of northern Alaska. We have identified 1247 pingo forms in the study region, ranging in height from 2 to 21m, with a mean height of 4.6m. Pingos in this region are of hydrostatic origin, with 98% located within 995 drained lake basins, most of which are underlain by thick eolian sand deposits. The highest pingo density (0.18km-2) occurs where streams have reworked these deposits. Morphometric analyses indicate that most pingos are small to medium in size (<200m diameter), gently to moderately sloping (<30??), circular to slightly elongate (mean circularity index of 0.88), and of relatively low height (2 to 5m). However, 57 pingos stand higher than 10m, 26 have a maximum slope greater than 30??, and 42 are larger than 200m in diameter. Comparison with a legacy pingo dataset based on 1950s stereo-pair photography indicates that 66 may have partially or completely collapsed over the last half-century. However, we mapped over 400 pingos not identified in the legacy dataset, and identified only three higher than 2m to have formed between ca. 1955 and ca. 2005, indicating that caution should be taken when comparing contemporary and legacy datasets derived by different techniques. This comprehensive database of pingo location and morphometry based on an IfSAR DSM may prove useful for land and resource managers as well as aid in the identification of pingo-like features on Mars. ?? 2011.

  3. Assessment of pingo distribution and morphometry using an IfSAR derived digital surface model, western Arctic Coastal Plain, Northern Alaska

    NASA Astrophysics Data System (ADS)

    Jones, Benjamin M.; Grosse, Guido; Hinkel, Kenneth M.; Arp, Christopher D.; Walker, Shane; Beck, Richard A.; Galloway, John P.

    2012-02-01

    Pingos are circular to elongate ice-cored mounds that form by injection and freezing of pressurized water in near-surface permafrost. Here we use a digital surface model (DSM) derived from an airborne Interferometric Synthetic Aperture Radar (IfSAR) system to assess the distribution and morphometry of pingos within a 40,000 km 2 area on the western Arctic Coastal Plain of northern Alaska. We have identified 1247 pingo forms in the study region, ranging in height from 2 to 21 m, with a mean height of 4.6 m. Pingos in this region are of hydrostatic origin, with 98% located within 995 drained lake basins, most of which are underlain by thick eolian sand deposits. The highest pingo density (0.18 km - 2 ) occurs where streams have reworked these deposits. Morphometric analyses indicate that most pingos are small to medium in size (< 200 m diameter), gently to moderately sloping (< 30°), circular to slightly elongate (mean circularity index of 0.88), and of relatively low height (2 to 5 m). However, 57 pingos stand higher than 10 m, 26 have a maximum slope greater than 30°, and 42 are larger than 200 m in diameter. Comparison with a legacy pingo dataset based on 1950s stereo-pair photography indicates that 66 may have partially or completely collapsed over the last half-century. However, we mapped over 400 pingos not identified in the legacy dataset, and identified only three higher than 2 m to have formed between ca. 1955 and ca. 2005, indicating that caution should be taken when comparing contemporary and legacy datasets derived by different techniques. This comprehensive database of pingo location and morphometry based on an IfSAR DSM may prove useful for land and resource managers as well as aid in the identification of pingo-like features on Mars.

  4. Sinkhole Precursors and Formation Mechanism along the Dead Sea Shorelines, Israel, Analyzed by InSAR, Field Mapping, Water Analysis and Elastic Modeling

    NASA Astrophysics Data System (ADS)

    Nof, R. N.; Baer, G.; Avni, Y.; Shviro, M.; Atzori, S.

    2014-12-01

    The water level of the Dead Sea (Israel and Jordan) has been dropping at an increasing rate since the 1960s, exceeding a meter per year during the last decade. This water-level drop has triggered the formation of sinkholes and land subsidence along the Dead Sea shorelines, resulting in severe economic loss and infrastructural damage. We demonstrate the use of Interferometric Synthetic Aperture Radar (InSAR) measurements from COSMO-SkyMed images, combined with an airborne Light Detection and Ranging (LiDAR) Digital Elevation Model to detect sinkhole-related subsidence. In several locations, precursory subsidence tens to more than a hundred meters wide, at rates between 0.5 and 2 mm/day started a few months to more than a year before an actual collapse of a sinkhole. The sinkholes, a few meters wide and up to 25 m deep, form generally at the perimeter of the subsiding areas. By means of a simplified model representing a distributed closure of a sill-like crack, we estimate the cavity volume occupied by the subsiding sedimentary overburden and explain the spatial relationships between the gradual surface subsidence and the sinkholes. The subsiding areas and successive sinkholes in a specific site migrate laterally, possibly due to progressive dissolution and widening of the underlying cavities. Combining InSAR measurements with sinkhole mapping and chemical and isotopic analyses of groundwater and surface water, we find a new mode of sinkhole formation. The sinkholes initiate by dissolution of a 10-20 m deep and 5-15 m thick halite layer by fresh groundwater. The process continues and accelerates as flash-floods are drained by existing or by newly formed sinkholes, the subsurface salt layer dissolves rapidly, the overlying ground subsides, and salt-saturated water seeps out downstream of the draining sinkholes. The number of sinkholes and the rates and dimensions of subsidence increase significantly during and immediately after the flood events, and decay

  5. GPS-Based Precision Baseline Reconstruction for the TanDEM-X SAR-Formation

    NASA Technical Reports Server (NTRS)

    Montenbruck, O.; vanBarneveld, P. W. L.; Yoon, Y.; Visser, P. N. A. M.

    2007-01-01

    The TanDEM-X formation employs two separate spacecraft to collect interferometric Synthetic Aperture Radar (SAR) measurements over baselines of about 1 km. These will allow the generation ofa global Digital Elevation Model (DEM) with an relative vertical accuracy of 2-4 m and a 10 m ground resolution. As part of the ground processing, the separation of the SAR antennas at the time of each data take must be reconstructed with a 1 mm accuracy using measurements from two geodetic grade GPS receivers. The paper discusses the TanDEM-X mission as well as the methods employed for determining the interferometric baseline with utmost precision. Measurements collected during the close fly-by of the two GRACE satellites serve as a reference case to illustrate the processing concept, expected accuracy and quality control strategies.

  6. Land subsidence caused by the East Mesa geothermal field, California, observed using SAR interferometry

    USGS Publications Warehouse

    Massonnet, D.; Holzer, T.; Vadon, H.

    1997-01-01

    Interferometric combination of pairs of synthetic aperture radar (SAR) images acquired by the ERS-1 satellite maps the deformation field associated with the activity of the East Mesa geothermal plant, located in southern California. SAR interferometry is applied to this flat area without the need of a digital terrain model. Several combinations are used to ascertain the nature of the phenomenon. Short term interferograms reveal surface phase changes on agricultural fields similar to what had been observed previously with SEASAT radar data. Long term (2 years) interferograms allow the study of land subsidence and improve prior knowledge of the displacement field, and agree with existing, sparse levelling data. This example illustrates the power of the interferometric technique for deriving accurate industrial intelligence as well as its potential for legal action, in cases involving environmental damages. Copyright 1997 by the American Geophysical Union.

  7. Nanoporous alumina-based interferometric transducers ennobled

    NASA Astrophysics Data System (ADS)

    Dronov, Roman; Jane, Andrew; Shapter, Joseph G.; Hodges, Alastair; Voelcker, Nicolas H.

    2011-08-01

    A high fidelity interferometric transducer is designed based on platinum-coated nanoporous alumina films. The ultrathin metal coating significantly improves fidelity of the interferometric fringe patterns in aqueous solution and increases the signal-to-noise ratio. The performance of this transducer is tested with respect to refractive index unit (RIU) sensitivity measured as a change in effective optical thickness (EOT) in response to a solvent change and compared to porous silicon based transducers. RIU sensitivity in the order of 55% is attainable for porous alumina providing excellent signal-to-noise ratio, which exceeds the sensitivity of current interferometric transducers. Finally, as a proof-of-principle, we demonstrate biosensing with two distinct immunoglobulin antibodies.A high fidelity interferometric transducer is designed based on platinum-coated nanoporous alumina films. The ultrathin metal coating significantly improves fidelity of the interferometric fringe patterns in aqueous solution and increases the signal-to-noise ratio. The performance of this transducer is tested with respect to refractive index unit (RIU) sensitivity measured as a change in effective optical thickness (EOT) in response to a solvent change and compared to porous silicon based transducers. RIU sensitivity in the order of 55% is attainable for porous alumina providing excellent signal-to-noise ratio, which exceeds the sensitivity of current interferometric transducers. Finally, as a proof-of-principle, we demonstrate biosensing with two distinct immunoglobulin antibodies. Electronic supplementary information (ESI) available: EOT sensorgram of adsorption of BSA and normal human IgG onto hydroxylated porous alumina, FWHM of interferometric spectra, and theoretical comparison of calculated RIU sensitivities for 1 µm thick porous alumina and porous silicon films. See DOI: 10.1039/c0nr00897d

  8. Confined aquifer head measurements and storage properties in the San Luis Valley, Colorado, from spaceborne InSAR observations

    NASA Astrophysics Data System (ADS)

    Chen, Jingyi; Knight, Rosemary; Zebker, Howard A.; Schreüder, Willem A.

    2016-05-01

    Interferometric Synthetic Aperture Radar (InSAR), a remote sensing technique for measuring centimeter-level surface deformation, is used to estimate hydraulic head in the confined aquifer of the San Luis Valley (SLV), Colorado. Reconstructing head measurements from InSAR in agricultural regions can be difficult, as InSAR phase data are often decorrelated due to vegetation growth. Analysis of 17 L-band ALOS PALSAR scenes, acquired between January 2007 and March 2011, demonstrates that comprehensive InSAR deformation measurements can be recovered over the vegetated groundwater basin with an improved processing strategy. Local skeletal storage coefficients and time delays between the head change and deformation are estimated through a joint InSAR-well data analysis. InSAR subsidence estimates are transformed to head changes with finer temporal and spatial resolution than is possible using existing well records alone. Both InSAR and well data suggest that little long-term water-storage loss occurred in the SLV over the study period and that inelastic compaction was negligible. The seasonal head variations derived from InSAR are consistent with the existing well data at most locations where confined aquifer pumping activity dominates. Our results demonstrate the advantages of InSAR measurements for basin-wide characterization of aquifer storage properties and groundwater levels over agricultural regions.

  9. Improvement of the Accuracy of InSAR Image Co-Registration Based On Tie Points - A Review.

    PubMed

    Zou, Weibao; Li, Yan; Li, Zhilin; Ding, Xiaoli

    2009-01-01

    Interferometric Synthetic Aperture Radar (InSAR) is a new measurement technology, making use of the phase information contained in the Synthetic Aperture Radar (SAR) images. InSAR has been recognized as a potential tool for the generation of digital elevation models (DEMs) and the measurement of ground surface deformations. However, many critical factors affect the quality of InSAR data and limit its applications. One of the factors is InSAR data processing, which consists of image co-registration, interferogram generation, phase unwrapping and geocoding. The co-registration of InSAR images is the first step and dramatically influences the accuracy of InSAR products. In this paper, the principle and processing procedures of InSAR techniques are reviewed. One of important factors, tie points, to be considered in the improvement of the accuracy of InSAR image co-registration are emphatically reviewed, such as interval of tie points, extraction of feature points, window size for tie point matching and the measurement for the quality of an interferogram. PMID:22399966

  10. Improvement of the Accuracy of InSAR Image Co-Registration Based On Tie Points – A Review

    PubMed Central

    Zou, Weibao; Li, Yan; Li, Zhilin; Ding, Xiaoli

    2009-01-01

    Interferometric Synthetic Aperture Radar (InSAR) is a new measurement technology, making use of the phase information contained in the Synthetic Aperture Radar (SAR) images. InSAR has been recognized as a potential tool for the generation of digital elevation models (DEMs) and the measurement of ground surface deformations. However, many critical factors affect the quality of InSAR data and limit its applications. One of the factors is InSAR data processing, which consists of image co-registration, interferogram generation, phase unwrapping and geocoding. The co-registration of InSAR images is the first step and dramatically influences the accuracy of InSAR products. In this paper, the principle and processing procedures of InSAR techniques are reviewed. One of important factors, tie points, to be considered in the improvement of the accuracy of InSAR image co-registration are emphatically reviewed, such as interval of tie points, extraction of feature points, window size for tie point matching and the measurement for the quality of an interferogram. PMID:22399966

  11. SAR calibration technology review

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

  12. Remote sensing measurements of thermokarst subsidence using InSAR

    NASA Astrophysics Data System (ADS)

    Liu, L.; Schaefer, K. M.; Chen, A. C.; Gusmeroli, A.; Zebker, H. A.; Zhang, T.

    2015-09-01

    Thawing of ice-rich permafrost followed by surface subsidence results in irregular, depressed landforms known as thermokarst. Many remote sensing studies have identified thermokarst landforms and mapped their changes. However, the intrinsic dynamic thermokarst process of surface subsidence remains a challenge to quantify and is seldom examined using remote sensing methods. In this study we used spaceborne interferometric synthetic aperture radar (InSAR) data to map surface subsidence trends at a thermokarst landform located near Deadhorse on the North Slope of Alaska. A pipeline access road constructed in the 1970s triggered the thawing of the permafrost, causing subsequent expansion of the thermokarst landform. Using Phased Array type L band Synthetic Aperture Radar images acquired by the Advanced Land Observing Satellite-1, our InSAR analysis reveals localized thermokarst subsidence of 2-8 cm/yr between 2006 and 2010, equivalent to an ice volume loss of about 1.2 × 107 m3/yr. Comparisons between InSAR subsidence trends and lidar microtopography suggest a characteristic time of 8 years of thermokarst development. We also quantitatively explain the difficulty, uncertainties, and possible biases in separating thermokarst-induced, irreversible subsidence from cyclic seasonal deformation. Our study illustrates that InSAR is an effective tool for mapping and studying active thermokarst processes and quantifying ice loss.

  13. The Performance Analysis Based on SAR Sample Covariance Matrix

    PubMed Central

    Erten, Esra

    2012-01-01

    Multi-channel systems appear in several fields of application in science. In the Synthetic Aperture Radar (SAR) context, multi-channel systems may refer to different domains, as multi-polarization, multi-interferometric or multi-temporal data, or even a combination of them. Due to the inherent speckle phenomenon present in SAR images, the statistical description of the data is almost mandatory for its utilization. The complex images acquired over natural media present in general zero-mean circular Gaussian characteristics. In this case, second order statistics as the multi-channel covariance matrix fully describe the data. For practical situations however, the covariance matrix has to be estimated using a limited number of samples, and this sample covariance matrix follow the complex Wishart distribution. In this context, the eigendecomposition of the multi-channel covariance matrix has been shown in different areas of high relevance regarding the physical properties of the imaged scene. Specifically, the maximum eigenvalue of the covariance matrix has been frequently used in different applications as target or change detection, estimation of the dominant scattering mechanism in polarimetric data, moving target indication, etc. In this paper, the statistical behavior of the maximum eigenvalue derived from the eigendecomposition of the sample multi-channel covariance matrix in terms of multi-channel SAR images is simplified for SAR community. Validation is performed against simulated data and examples of estimation and detection problems using the analytical expressions are as well given. PMID:22736976

  14. First Image Products from EcoSAR - Osa Peninsula, Costa Rica

    NASA Technical Reports Server (NTRS)

    Osmanoglu, Batuhan; Lee, SeungKuk; Rincon, Rafael; Fatuyinbo, Lola; Bollian, Tobias; Ranson, Jon

    2016-01-01

    Designed especially for forest ecosystem studies, EcoSAR employs state-of-the-art digital beamforming technology to generate wide-swath, high-resolution imagery. EcoSARs dual antenna single-pass imaging capability eliminates temporal decorrelation from polarimetric and interferometric analysis, increasing the signal strength and simplifying models used to invert forest structure parameters. Antennae are physically separated by 25 meters providing single pass interferometry. In this mode the radar is most sensitive to topography. With 32 active transmit and receive channels, EcoSARs digital beamforming is an order of magnitude more versatile than the digital beamforming employed on the upcoming NISAR mission. EcoSARs long wavelength (P-band, 435 MHz, 69 cm) measurements can be used to simulate data products for ESAs future BIOMASS mission, allowing scientists to develop algorithms before the launch of the satellite. EcoSAR can also be deployed to collect much needed data where BIOMASS satellite wont be allowed to collect data (North America, Europe and Arctic), filling in the gaps to keep a watchful eye on the global carbon cycle. EcoSAR can play a vital role in monitoring, reporting and verification schemes of internationals programs such as UN-REDD (United Nations Reducing Emissions from Deforestation and Degradation) benefiting global society. EcoSAR was developed and flown with support from NASA Earth Sciences Technology Offices Instrument Incubator Program.

  15. New Ground Truth Capability from InSAR Time Series Analysis

    SciTech Connect

    Buckley, S; Vincent, P; Yang, D

    2005-07-13

    We demonstrate that next-generation interferometric synthetic aperture radar (InSAR) processing techniques applied to existing data provide rich InSAR ground truth content for exploitation in seismic source identification. InSAR time series analyses utilize tens of interferograms and can be implemented in different ways. In one such approach, conventional InSAR displacement maps are inverted in a final post-processing step. Alternatively, computationally intensive data reduction can be performed with specialized InSAR processing algorithms. The typical final result of these approaches is a synthesized set of cumulative displacement maps. Examples from our recent work demonstrate that these InSAR processing techniques can provide appealing new ground truth capabilities. We construct movies showing the areal and temporal evolution of deformation associated with previous nuclear tests. In other analyses, we extract time histories of centimeter-scale surface displacement associated with tunneling. The potential exists to identify millimeter per year surface movements when sufficient data exists for InSAR techniques to isolate and remove phase signatures associated with digital elevation model errors and the atmosphere.

  16. Monitoring of Land Subsidence in Ravenna Municipality Using Integrated SAR - GPS Techniques: Description and First Results

    NASA Astrophysics Data System (ADS)

    Artese, G.; Fiaschi, S.; Di Martire, D.; Tessitore, S.; Fabris, M.; Achilli, V.; Ahmed, A.; Borgstrom, S.; Calcaterra, D.; Ramondini, M.; Artese, S.; Floris, M.; Menin, A.; Monego, M.; Siniscalchi, V.

    2016-06-01

    The Emilia Romagna Region (N-E Italy) and in particular the Adriatic Sea coastline of Ravenna, is affected by a noticeable subsidence that started in the 1950s, when the exploitation of on and off-shore methane reservoirs began, along with the pumping of groundwater for industrial uses. In such area the current subsidence rate, even if lower than in the past, reaches the -2 cm/y. Over the years, local Authorities have monitored this phenomenon with different techniques: spirit levelling, GPS surveys and, more recently, Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques, confirming the critical situation of land subsidence risk. In this work, we present the comparison between the results obtained with DInSAR and GPS techniques applied to the study of the land subsidence in the Ravenna territory. With regard to the DInSAR, the Small Baseline Subset (SBAS) and the Coherent Pixel Technique (CPT) techniques have been used. Different SAR datasets have been exploited: ERS-1/2, ENVISAT, TerraSAR-X and Sentinel-1. Some GPS campaigns have been also carried out in a subsidence prone area. 3D vertices have been selected very close to existing persistent scatterers in order to link the GPS measurement results to the SAR ones. GPS data were processed into the International reference system and the comparisons between the coordinates, for the first 6 months of the monitoring, provided results with the same trend of the DInSAR data, even if inside the precision of the method.

  17. Six years of land subsidence in shanghai revealed by JERS-1 SAR data

    USGS Publications Warehouse

    Damoah-Afari, P.; Ding, X.-L.; Li, Z.; Lu, Zhiming; Omura, M.

    2008-01-01

    Differential interferometric synthetic aperture radar (SAR) (DInSAR) has proven to be very useful in mapping and monitoring land subsidence in many regions of the world. Shanghai, China's largest city, is one of such areas suffering from land subsidence as a result of severe withdrawal of groundwater for different usages. DInSAR application in Shanghai with the C-band European Remote Sensing 1 & 2 (ERS-1/2) SAR data has been difficult mainly due to the problem of decorrelation of InSAR pairs with temporal baselines larger than 10 months. To overcome the coherence loss of C-band InSAR data, we used eight L-band Japanese Earth Resource Satellite (JERS-1) SAR data acquired during 2 October 1992 to 15 July 1998 to study land subsidence phenomenon in Shanghai. Three of the images were used to produce two separate digital elevation models (DEMs) of the study area to remove topographic fringes from the interferograms used for subsidence mapping. Six interferograms were used to generate 2 different time series of deformation maps over Shanghai. The cumulative subsidence map generated from each of the time series is in agreement with the land subsidence measurements of Shanghai city from 1990-1998, produced from other survey methods. ?? 2007 IEEE.

  18. Landslide Mapping Using SqueeSAR Data

    NASA Astrophysics Data System (ADS)

    Ferretti, A.; Bellotti, F.; Alberti, S.; Allievi, J.; Del Conte, S.; Tamburini, A.; Broccolato, M.; Ratto, S.; Alberto, W.

    2011-12-01

    SqueeSAR represents the most recent advancement of PSInSAR algorithm. By exploiting signal radar returns both from Permanent and Distributed Scatterers (PS and DS), it is able to detect millimetre displacements over long periods and large areas and to obtain a significant increase in the spatial density of ground measurement points. SqueeSAR analysis is complementary to conventional geological and geomorphological studies in landslide mapping over wide areas, traditionally based on aerial-photo interpretation and field surveys. However, whenever surface displacement rates are low (mm to cm per year), assessing landslide activity is difficult or even impossible without a long-term monitoring tool, as in the case of Deep-seated Gravitational Slope Deformations (DGSD), typically characterized by large areal extent and subtle surface displacement. The availability of surface displacement time series per each measurement point allows one to have both a synoptic overview, at regional scale, as well as an in depth characterization of the instability phenomena analyzed, a meaningful support to the design of traditional monitoring networks and the efficiency testing of remedial works. When data archives are available, SqueeSAR can also provide valuable information before the installation of any terrestrial measurement system. The Italian authorities increasing interest in the application of SqueeSAR as a standard monitoring tool to help hydrogeological risk assessment, resulted in a national project, Piano Straordinario di Telerilevamento (PST), founded by the Ministry of the Environment. The aim of the project was to create the first interferometric database on a national scale for mapping unstable areas. More than 12,000 ERS and ENVISAT radar scenes acquired over Italy were processed spanning the period 1992-2010, proving that, in less than ten years, radar interferometry has become a standard monitoring tool. Recently, many regional governments in Italy have applied

  19. Large Scale Assessment of Radio Frequency Interference Signatures in L-band SAR Data

    NASA Astrophysics Data System (ADS)

    Meyer, F. J.; Nicoll, J.

    2011-12-01

    Imagery of L-band Synthetic Aperture Radar (SAR) systems such as the PALSAR sensor on board the Advanced Land Observing Satellite (ALOS) has proven to be a valuable tool for observing environmental changes around the globe. Besides offering 24/7 operability, the L-band frequency provides improved interferometric coherence, and L-band polarimetric data has shown great potential for vegetation monitoring, sea ice classification, and the observation of glaciers and ice sheets. To maximize the benefit of missions such as ALOS PALSAR for environmental monitoring, data consistency and calibration are vital. Unfortunately, radio frequency interference (RFI) signatures from ground-based radar systems regularly impair L-band SAR data quality and consistency. With this study we present a large-scale analysis of typical RFI signatures that are regularly observed in L-band SAR data over the Americas. Through a study of the vast archive of L-band SAR data in the US Government Research Consortium (USGRC) data pool at the Alaska Satellite Facility (ASF) we were able to address the following research goals: 1. Assessment of RFI Signatures in L-band SAR data and their Effects on SAR Data Quality: An analysis of time-frequency properties of RFI signatures in L-band SAR data of the USGRC data pool is presented. It is shown that RFI-filtering algorithms implemented in the operational ALOS PALSAR processor are not sufficient to remove all RFI-related artifacts. In examples, the deleterious effects of RFI on SAR image quality, polarimetric signature, SAR phase, and interferometric coherence are presented. 2. Large-Scale Assessment of Severity, Spatial Distribution, and Temporal Variation of RFI Signatures in L-band SAR data: L-band SAR data in the USGRC data pool were screened for RFI using a custom algorithm. Per SAR frame, the algorithm creates geocoded frame bounding boxes that are color-coded according to RFI intensity and converted to KML files for analysis in Google Earth. From

  20. Balloon-based interferometric techniques

    NASA Technical Reports Server (NTRS)

    Rees, David

    1985-01-01

    A balloon-borne triple-etalon Fabry-Perot Interferometer, observing the Doppler shifts of absorption lines caused by molecular oxygen and water vapor in the far red/near infrared spectrum of backscattered sunlight, has been used to evaluate a passive spaceborne remote sensing technique for measuring winds in the troposphere and stratosphere. There have been two successful high altitude balloon flights of the prototype UCL instrument from the National Scientific Balloon Facility at Palestine, TE (May 80, Oct. 83). The results from these flights have demonstrated that an interferometer with adequate resolution, stability and sensitivity can be built. The wind data are of comparable quality to those obtained from operational techniques (balloon and rocket sonde, cloud-top drift analysis, and from the gradient wind analysis of satellite radiance measurements). However, the interferometric data can provide a regular global grid, over a height range from 5 to 50 km in regions of clear air. Between the middle troposphere (5 km) and the upper stratosphere (40 to 50 km), an optimized instrument can make wind measurements over the daylit hemisphere with an accuracy of about 3 to 5 m/sec (2 sigma). It is possible to obtain full height profiles between altitudes of 5 and 50 km, with 4 km height resolution, and a spatial resolution of about 200 km, along the orbit track. Below an altitude of about 10 km, Fraunhofer lines of solar origin are possible targets of the Doppler wind analysis. Above an altitude of 50 km, the weakness of the backscattered solar spectrum (decreasing air density) is coupled with the low absorption crosssection of all atmospheric species in the spectral region up to 800 nm (where imaging photon detectors can be used), causing the along-the-track resolution (or error) to increase beyond values useful for operational purposes. Within the region of optimum performance (5 to 50 km), however, the technique is a valuable potential complement to existing wind

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

    NASA Technical Reports Server (NTRS)

    Vanzyl, Jakob J. (Editor)

    1991-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  3. Growth of a young pingo in the Canadian Arctic observed by RADARSAT-2 interferometric satellite radar

    NASA Astrophysics Data System (ADS)

    Samsonov, S. V.; Lantz, T. C.; Kokelj, S. V.; Zhang, Y.

    2015-11-01

    Advancements in radar technology are increasing our ability to detect earth surface deformation in permafrost environments. In this paper we use satellite Differential Interferometric Synthetic Aperture Radar (DInSAR) to describe the growth of a previously unreported pingo in the Tuktoyaktuk Coastlands. High-resolution RADARSAT-2 imagery (2011-2014) analyzed with the Multidimensional Small Baseline Subset (MSBAS) DInSAR revealed a maximum 2.7 cm yr-1 of domed uplift located in a drained lake basin. Observed changes in elevation were modeled as a 348 m × 290 m uniformly loaded elliptical plate with clamped edge. Model results suggest that this feature is one of the largest diameter pingos in the region that is presently growing. Analysis of historical aerial photographs showed that ground uplift at this location initiated sometime between 1935 and 1951 following lake drainage. Uplift is largely due to the growth of intrusive ice, because the 9 % expansion of pore water associated with permafrost aggradation into saturated sands is not sufficient to explain the observed short- and long-term deformation rates. The modeled thickness of permafrost using the Northern Ecosystem Soil Temperature (NEST) was consistent with the maximum height of this feature and the 1972-2014 elevation changes estimated from aerial photographs, suggesting that permafrost aggradation is resulting in the freezing a sub-pingo water lens. Seasonal variation in the uplift rate seen in the DInSAR data also matches the modeled seasonal pattern in the deepening rate of freezing front. This study demonstrates that interferometric satellite radar can successfully contribute to understanding the dynamics of terrain uplift in response to permafrost aggradation and ground ice development in remote polar environments, and highlights possible application of detecting deformation of Martian landscapes. However, our DInSAR data did not show clear growth at other smaller pingos in contrast with field studies

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

    SciTech Connect

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

    1990-04-15

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

  5. The evolutionary trend in airborne and satellite radar altimeters

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  6. Transient volcano deformation sources imaged with interferometric synthetic aperture radar: Application to Seguam Island, Alaska

    USGS Publications Warehouse

    Masterlark, Timothy; Lu, Zhong

    2004-01-01

    Thirty interferometric synthetic aperture radar (InSAR) images, spanning various intervals during 1992–2000, document coeruptive and posteruptive deformation of the 1992–1993 eruption on Seguam Island, Alaska. A procedure that combines standard damped least squares inverse methods and collective surfaces, identifies three dominant amorphous clusters of deformation point sources. Predictions generated from these three point source clusters account for both the spatial and temporal complexity of the deformation patterns of the InSAR data. Regularized time series of source strength attribute a distinctive transient behavior to each of the three source clusters. A model that combines magma influx, thermoelastic relaxation, poroelastic effects, and petrologic data accounts for the transient, interrelated behavior of the source clusters and the observed deformation. Basaltic magma pulses, which flow into a storage chamber residing in the lower crust, drive this deformational system. A portion of a magma pulse is injected into the upper crust and remains in storage during both coeruption and posteruption intervals. This injected magma degasses and the volatile products accumulate in a shallow poroelastic storage chamber. During the eruption, another portion of the magma pulse is transported directly to the surface via a conduit roughly centered beneath Pyre Peak on the west side of the island. A small amount of this magma remains in storage during the eruption, and posteruption thermoelastic contraction ensues. This model, made possible by the excellent spatial and temporal coverage of the InSAR data, reveals a relatively simple system of interrelated predictable processes driven by magma dynamics.

  7. Modeling magnitude statistics of multilook SAR interferograms by generalizing G distributions

    NASA Astrophysics Data System (ADS)

    Gao, Gui; Shi, Gongtao

    2015-06-01

    Statistical analysis of multilook interferograms is a foundational issue in sensor signal processing of multiple-channel synthetic aperture radar (SAR), such as slow ground moving target indication (GMTI) in along-track interferometric (ATI) SAR. By an approximate derivation of the product of two modified Bessel functions, we propose in this paper a distribution (denoted simply as ΓIn) to model the interferometric magnitude of homogeneous clutter and analyze the capability of approximation using ΓIn according to numerical calculations. Following this, under the frame of the product model and by utilizing ΓIn, we analytically provide two distributions, KIn and Gn0, corresponding to heterogeneous and extremely heterogeneous terrain clutter, respectively. We show that the proposed ΓIn,KIn and G In0 are the multi-channel generalizations of the well-known Γ, K and G0, respectively, which belong to the special cases of G distribution for single-channel SAR images. Finally, the estimators of the proposed models are obtained by applying the Method of Log Cumulants (MoLC), which can accurately calculate the contained parameters. Experiments performed on the National Aeronautics and Space Administration Jet Propulsion Laboratory's (NASA/JPL) AirSAR images that used the Kullback-Leibler (KL) divergence as a similarity measurement verified the performance of the proposed models and estimators.

  8. Research on data fusion for monitoring ground subsidence using InSAR

    NASA Astrophysics Data System (ADS)

    Ma, Jing; Zhang, Qin; Liu, Xianglei; Zhao, Chaoying

    2008-12-01

    Interferometric Synthetic Aperture Radar (InSAR) magtitude map, extracted from Differential- Interferometric Syntheric Aperture Radar (D-InSAR) technology, has a low-resolution, so it has a certain limitation to the explanation and analysis of subsiding area. In order to solve the problem of lacking enough spatial information of D-InSAR image, in this essay we take a data fusion between D-InSAR image and high resolution Remote Sensing (RS) image, obtaining an image containing subsiding information and high-resolution spatial information. This paper mainly focuses on the study of a Mag-Phase algorithm (MPH) algorithm and other fusion algorithms including Hue-Intensity-Saturation (HIS) transformation, Principal Component Analysis (PCA) transformation, Product fusion, Ratio fusion, Wavelet fusion for magtitude map and deformation map, and we take the deformation map and panchromatic (PAN) image of Enhanced Thematic Mapper + (ETM+) (magtitude map) of Xi'an area as an example to do data fusion according to the algorithms above. At last, a comprehensive evaluation and analysis for fusion images is made with subjective and objective evaluation criteria, and a conclusion that MPH fusion algorithm is better than others is also obtained.

  9. Note: Near infrared interferometric silicon wafer metrology.

    PubMed

    Choi, M S; Park, H M; Joo, K N

    2016-04-01

    In this investigation, two near infrared (NIR) interferometric techniques for silicon wafer metrology are described and verified with experimental results. Based on the transparent characteristic of NIR light to a silicon wafer, the fiber based spectrally resolved interferometry can measure the optical thickness of the wafer and stitching low coherence scanning interferometry can reconstruct entire surfaces of the wafer. PMID:27131722

  10. Quantum Limits in Interferometric GW Antennas

    NASA Technical Reports Server (NTRS)

    Romano, R.; Barone, F.; Maddalena, P.; Solimeno, S.; Zaccaria, F.; Manko, M. A.; Manko, V. I.

    1996-01-01

    We discuss a model for interferometric GW antennas illuminated by a laser beam and a vacuum squeezed field. The sensitivity of the antenna will depend on the properties of the radiation entering the two ports and on the optical characteristics of the interferometer components, e.g. mirrors, beam-splitter, lenses.

  11. Water Vapor Products from Differential-InSAR with Auxiliary Calibration Data: Accuracy and Statistics

    NASA Astrophysics Data System (ADS)

    Gong, W.; Meyer, F. J.; Webley, P.

    2014-12-01

    Although water vapor disturbance has been long term recognized as the major error source in differential Interferometric Synthetic Aperture Radar (d-InSAR) techniques for the ground deformation monitoring and topography reconstruction, it provides opportunities to extract the atmospheric water-vapor information from satellite SAR imageries that can be further used to support studies on earth energy budget, climate, the hydrological cycle, and meteorological forecasting, etc. The water vapor contribution in interferometric phases is normally referred as the atmospheric delay dominated by water vapor rather than condensed water (e.g. cloud). D-InSAR can produce maps of the column water vapor amounts (equivalent to integrated water vapor (IWV) or Precipitable Water Vapor (PWV) in other literatures) that are important parameters quantitatively describe the total amount of water vapor overlying a point on the earth surface. Similar products have been operationally produced in multi-spectrum remote sensing, e.g. Moderate-resolution Imaging Spectroradiometer (MODIS) with a spatial resolution in 500 m to 1km; Whereas, the PWV products derived by d-InSAR have remarkably high spatial resolution that can capture fine scale of water vapor variations in space as small as tens of meters or even less. In recent years, some efforts have been made to derive the water vapor products from interferogram and analyze the corresponding products quality, such as studies comparing integrated water vapor derived from interferometric phases to other measurements (e.g. MERIS, MODIS, GNSS), studies on deriving absolute water vapor products from d-InSAR, and studies on integrating d-InSAR water vapor products in meteorological numerical forecast. In this study, considering these limitation factors and based on previous studies, we discuss the accuracy and statistics of the water vapor products from satellite SAR, including (1) Accuracy of the differential water vapor products; (2) Sources of

  12. Hybrid polarity SAR architecture

    NASA Astrophysics Data System (ADS)

    Raney, R. Keith

    2009-05-01

    A space-based synthetic aperture radar (SAR) designed to provide quantitative information on a global scale implies severe requirements to maximize coverage and to sustain reliable operational calibration. These requirements are best served by the hybrid-polarity architecture, in which the radar transmits in circular polarization, and receives on two orthogonal linear polarizations, coherently, retaining their relative phase. This paper summarizes key attributes of hybrid-polarity dual- and quadrature-polarized SARs, reviews the associated advantages, formalizes conditions under which the signal-to-noise ratio is conserved, and describes the evolution of this architecture from first principles.

  13. InSAR Scientific Computing Environment - The Home Stretch

    NASA Astrophysics Data System (ADS)

    Rosen, P. A.; Gurrola, E. M.; Sacco, G.; Zebker, H. A.

    2011-12-01

    The Interferometric Synthetic Aperture Radar (InSAR) Scientific Computing Environment (ISCE) is a software development effort in its third and final year within the NASA Advanced Information Systems and Technology program. The ISCE is a new computing environment for geodetic image processing for InSAR sensors enabling scientists to reduce measurements directly from radar satellites to new geophysical products with relative ease. The environment can serve as the core of a centralized processing center to bring Level-0 raw radar data up to Level-3 data products, but is adaptable to alternative processing approaches for science users interested in new and different ways to exploit mission data. Upcoming international SAR missions will deliver data of unprecedented quantity and quality, making possible global-scale studies in climate research, natural hazards, and Earth's ecosystem. The InSAR Scientific Computing Environment has the functionality to become a key element in processing data from NASA's proposed DESDynI mission into higher level data products, supporting a new class of analyses that take advantage of the long time and large spatial scales of these new data. At the core of ISCE is a new set of efficient and accurate InSAR algorithms. These algorithms are placed into an object-oriented, flexible, extensible software package that is informed by modern programming methods, including rigorous componentization of processing codes, abstraction and generalization of data models. The environment is designed to easily allow user contributions, enabling an open source community to extend the framework into the indefinite future. ISCE supports data from nearly all of the available satellite platforms, including ERS, EnviSAT, Radarsat-1, Radarsat-2, ALOS, TerraSAR-X, and Cosmo-SkyMed. The code applies a number of parallelization techniques and sensible approximations for speed. It is configured to work on modern linux-based computers with gcc compilers and python

  14. PolInSAR at Low Frequency and Ionospheric Effects

    NASA Astrophysics Data System (ADS)

    Dubois-Fernandez, P.; Angelliaume, S.; Truong-Loi, M.-L.; Freeman, A.; Pottier, E.

    2009-04-01

    Global warning is now known to be the major environmental issue mankind will have to face in the next decade. Monitoring of vegetation and biomass is clearly an essential piece of information required at all levels ranging from the scientific studies to understand and forecast, to the political actors and government leaders responsible for drafting remediation policies and evaluating their impact. Microwave remote sensing with the low-frequency SAR technique can provide a useful characterization of forest (spatial coverage, species, density, height...) at a global scale, relying on the all-weather imaging capabilities of SAR linked with the significant penetration of the low-frequency EM wave in the canopy. The published techniques for forest characterization from low frequency SAR data include radiometry inversion, polarimetric inversion based on the anisotropy parameters and PolInSAR Random Volume Over Ground inversion [1]. In this paper, we will more specifically concentrate on the PolInSAR technique and the impact of ionospheric effect on this inversion. PolInSAR at low frequency can be envisioned with two radar platforms flying in formation or as a repeat pass mission. The second alternative is more plausible given the cost and the size of a low frequency SAR instrument. However the two cases will be discussed in the paper. Among the challenges, the following questions need to be addressed: · What is the impact of ionosphere and Faraday rotation on the PolInSAR inversion results? · Is it necessary to correct the data prior to applying the inversion and what is the highest Faraday rotation for which a correction is not necessary? · What is the effect of loss of interferometric coherence and could this be compensated for? · Can the technique provide an estimation of the Faraday rotation or the differential Faraday rotation? · How does ionospheric and calibration effects interact? · What are the implications on a compact polarimetry mode of operation?

  15. Fundamental SAR ATR performance predictions for design trade-offs

    NASA Astrophysics Data System (ADS)

    Horowitz, Larry L.; Brendel, Gary F.

    1997-07-01

    This paper discusses work toward a fundamental, algorithm- independent view of the ATR performance that can be achieved using SAR data. Such ATR performance predictions are intended to enable evaluation of performance tradeoffs for SAR designs, including both parameter selections and added domains of SAR observation, such as 3D, full polarimetry, multiaspect and/or multifrequency. In the paper we evaluate the classification error for two tactical targets using a Monte Carlo technique. A number of approximations are made and are detailed in the paper. Data on target signatures come from pencil-beam laser data and target photographs, which determine shadowing of the ground clutter. A single aspect angle is used for each target in the initial results. A layer of radar netting is modeled on both targets. This information is used as 'ground truth', to compute the average power that would be seen in each pixel of a SAR image, for each target. SAR image trials are then generated using independent Rayleigh amplitude fades in each pixel. In an optimal Bayesian fashion, the smaller of the probabilities of target (T1) or T2 given the trial image data is the error probability for that trial. An average over the Monte Carlo image trials yields the overall classification error probability. Comments are given on reducing the number of required trials in such a Monte Carlo. THree results of the work are shown. First, a tradeoff is made of ATR performance versus SAR resolution. ATR improves as the resolution is made finer, and physical reasons for this are discussed. Second, the relative ATR utility is determined for those pixels where at least one target has scatterer as compared with those pixels where the targets differ only in the degree to which they shadow the ground clutter. Third, an early analytical result is given for interferometric SAR, showing the physical reason behind the potential of height-sensing SAR to improve ATR - the possibility of canceling the background

  16. A Network Inversion Filter combining GNSS and InSAR for tectonic slip modeling

    NASA Astrophysics Data System (ADS)

    Bekaert, D. P. S.; Segall, P.; Wright, T. J.; Hooper, A. J.

    2016-03-01

    Studies of the earthquake cycle benefit from long-term time-dependent slip modeling, as it can be a powerful means to improve our understanding on the interaction of earthquake cycle processes such as interseismic, coseismic, post seismic, and aseismic slip. Observations from Interferometric Synthetic Aperture Radar (InSAR) allow us to model slip at depth with a higher spatial resolution than when using Global Navigation Satellite Systems (GNSS) alone. While the temporal resolution of InSAR has typically been limited, the recent fleet of SAR satellites including Sentinel-1, COSMO-SkyMED, and RADARSAT-2 permits the use of InSAR for time-dependent slip modeling at intervals of a few days when combined. With the vast amount of SAR data available, simultaneous data inversion of all epochs becomes challenging. Here we expanded the original network inversion filter to include InSAR observations of surface displacements in addition to GNSS. In the Network Inversion Filter (NIF) framework, geodetic observations are limited to those of a given epoch, with a stochastic model describing slip evolution over time. The combination of the Kalman forward filtering and backward smoothing allows all geodetic observations to constrain the complete observation period. Combining GNSS and InSAR allows modeling of time-dependent slip at unprecedented spatial resolution. We validate the approach with a simulation of the 2006 Guerrero slow slip event. We highlight the importance of including InSAR covariance information and demonstrate that InSAR provides an additional constraint on the spatial extent of the slow slip.

  17. A persistent scatterer interpolation for retrieving accurate ground deformation over InSAR-decorrelated agricultural fields

    NASA Astrophysics Data System (ADS)

    Chen, Jingyi; Zebker, Howard A.; Knight, Rosemary

    2015-11-01

    Interferometric synthetic aperture radar (InSAR) is a radar remote sensing technique for measuring surface deformation to millimeter-level accuracy at meter-scale resolution. Obtaining accurate deformation measurements in agricultural regions is difficult because the signal is often decorrelated due to vegetation growth. We present here a new algorithm for retrieving InSAR deformation measurements over areas with severe vegetation decorrelation using adaptive phase interpolation between persistent scatterer (PS) pixels, those points at which surface scattering properties do not change much over time and thus decorrelation artifacts are minimal. We apply this algorithm to L-band ALOS interferograms acquired over the San Luis Valley, Colorado, and the Tulare Basin, California. In both areas, the pumping of groundwater for irrigation results in deformation of the land that can be detected using InSAR. We show that the PS-based algorithm can significantly reduce the artifacts due to vegetation decorrelation while preserving the deformation signature.

  18. Application of Satellite SAR Imagery in Mapping the Active Layer of Arctic Permafrost

    NASA Technical Reports Server (NTRS)

    Li, Shu-Sun; Romanovsky, V.; Lovick, Joe; Wang, Z.; Peterson, Rorik

    2003-01-01

    A method of mapping the active layer of Arctic permafrost using a combination of conventional synthetic aperture radar (SAR) backscatter and more sophisticated interferometric SAR (INSAR) techniques is proposed. The proposed research is based on the sensitivity of radar backscatter to the freeze and thaw status of the surface soil, and the sensitivity of INSAR techniques to centimeter- to sub-centimeter-level surface differential deformation. The former capability of SAR is investigated for deriving the timing and duration of the thaw period for surface soil of the active layer over permafrost. The latter is investigated for the feasibility of quantitative measurement of frost heaving and thaw settlement of the active layer during the freezing and thawing processes. The resulting knowledge contributes to remote sensing mapping of the active layer dynamics and Arctic land surface hydrology.

  19. Impact of ionosphere on high-bandwidth chirp in L-band SAR and its mitigation

    NASA Astrophysics Data System (ADS)

    Nandy, Partha Sarathi; Putrevu, Deepak

    2016-05-01

    There is a trend of SAR imaging at low frequencies (VHF/UHF, L-band) and wide bandwidth, for penetration into foliage for high resolution applications. The propagation of spaceborne radar signals operating at L-band frequency or below can be seriously affected by the ionosphere. While these effects are negligible at X-band, Faraday Rotation and the frequency-dependent path delays can become seriously problematic at L-band. Range delay, interferometric phase bias, range defocussing and Faraday rotation are the most prominent ones. Due to ionospheric effects, blind use of a generic matched filter causes inaccuracies when correlating the received signal with transmitted replica. In this paper we study the effects of frequency dependent path delays in L-band SAR chirp signal due to ionospheric electron density. Also a method to correct ionospheric anomalies without the knowledge of electron content level in a single SAR acquisition is proposed.

  20. High-speed railway bridge dynamic measurement based on GB-InSAR technology

    NASA Astrophysics Data System (ADS)

    Liu, Miao; Ding, Ke-liang; Liu, Xianglei; Song, Zichao

    2015-12-01

    It is an important task to evaluate the safety during the life of bridges using the corresponding vibration parameters. With the advantages of non-contact and high accuracy, the new remote measurement technology of GB-InSAR is suitable to make dynamic measurement for bridges to acquire the vibration parameters. Three key technologies, including stepped frequency-continuous wave technique, synthetic aperture radar and interferometric measurement technique, are introduced in this paper. The GB-InSAR is applied for a high-speed railway bridge to measure of dynamic characteristics with the train passing which can be used to analyze the safety of the monitored bridge. The test results shown that it is an reliable non-contact technique for GB-InSAR to acquire the dynamic vibration parameter for the high-speed railway bridges.

  1. InSAR-Detected Tidal Flow in Louisiana's Coastal Wetlands

    NASA Astrophysics Data System (ADS)

    Oliver-Cabrera, T.; Wdowinski, S.

    2014-12-01

    The Louisiana coast is among the most productive coastal area in the US and home to the largest coastal wetland area in the nation. However, Louisiana coastal wetlands have been threatened by natural (sea-level rise) and human (infrastructure development) stresses; they constitute the major part of the wetland loss of the country. Monitoring Louisiana's coastal wetlands represent a large challenge for local and federal authorities due to the large amount of area and hostile environment. Insofar, optical remote sensing observations have been used to classify the wetlands, monitor land cover changes, and assess the wetland loss over time. However, optical data is insensitive to surface flow and, hence, unable to detect the width of the tidal zone and changes in this area over time. SAR interferometry can provide useful information and ease the monitoring task. Wetland InSAR is the only application of the InSAR technology that provides information of aquatic surface. It provides useful information on surface water level changes in both inland and coastal wetlands. In this study, we use InSAR and tide gauge observations to detect and compare surface water level changes in response to ocean tide propagation through the Louisiana coastal wetlands. Our data consist of ALOS PALSAR, Radarsat-1 and tide gauge information over the coast of Louisiana. In order to detect water level changes, we used mainly high coherence interferferograms with short temporal baselines (46-92 days for ALOS data and 24-48 days for Radarsat-1). Interferometric processing of the data provides details maps of water level changes in the coastal zone. Preliminary results indicate tidal changes of up 30 cm and that tidal flow is limited to 8-10 km from the open water. Our results also show that the tidal flow is disrupted by various man-made structures as, canals and roads. The high spatial resolution wetland InSAR observations can provide useful constraints for detailed coastal wetland flow models.

  2. Surface Ruptures and Building Damage of the 2003 Bam, Iran, Earthquake Mapped by Satellite Synthetic Aperture Radar Interferometric Correlation

    NASA Technical Reports Server (NTRS)

    Fielding, Eric J.; Talebian, M.; Rosen, P. A.; Nazari, H.; Jackson, J. A.; Ghorashi, M.; Walker, R.

    2005-01-01

    We use the interferometric correlation from Envisat synthetic aperture radar (SAR) images to map the details of the surface ruptures related to the 26 December 2003 earthquake that devastated Bam, Iran. The main strike-slip fault rupture south of the city of Bam has a series of four segments with left steps shown by a narrow line of low correlation in the coseismic interferogram. This also has a clear expression in the field because of the net extension across the fault. Just south of the city limits, the surface strain becomes distributed over a width of about 500 m, probably because of a thicker layer of soft sedimentary material.

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

    NASA Technical Reports Server (NTRS)

    Moes, Timothy R.

    2009-01-01

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

  4. Space Borne and Ground Based InSAR Data Integration: The Åknes Test Site

    NASA Astrophysics Data System (ADS)

    Bardi, Federica; Raspini, Federico; Ciampalini, Andrea; Kristensen, Lene; Rouyet, Line; Rune Lauknes, Tom; Frauenfelder, Regula; Casagli, Nicola

    2016-04-01

    This work concerns a proposal of integration between InSAR (Interferometric Synthetic Aperture Radar) data acquired by ground based (GB) and satellite platforms. The selected test site is the Åknes rockslide, which affects the western Norwegian coast; the availability of GB-InSAR and satellite InSAR data, and the accessibility of a wide literature make the landslide suitable for testing the proposed procedure. The first step consists in the organization of a geodatabase, performed in GIS environment, containing all the available data. The second step concerns the analysis of satellite and GB-InSAR data, separately. Two datasets, acquired by RADARSAT-2 (related to a period between October 2008 and August 2013) and by a combination of TerraSAR-X and TanDEM-X (acquired between July 2010 and October 2012), both of them in ascending orbit, processed applying SBAS (Small BAseline Subset), are available. GB-InSAR data related to 5 different campaigns of measurements, referred to the summer seasons of 2006, 2008, 2009, 2010 and 2012 are available too. The third step relies on data integration, performed firstly on a qualitative point of view and lately on a semi-quantitative point of view. The results of the proposed procedure have been validated by comparing them with GPS (Global Positioning System) data.

  5. Study of high SAR backscattering caused by an increase of soil moisture over a sparsely vegetated area: Implications for characteristics of backscattering

    USGS Publications Warehouse

    Lu, Zhiming; Meyer, D.J.

    2002-01-01

    We used interferometric methods on a pair of repeat-pass ERS-1 synthetic aperture radar (SAR) images to study soil moisture changes over sparsely vegetated targets. The intensity of the SAR image acquired at one time was higher than that of an image acquired at an earlier time. We used a correlation image computed from the SAR image pair to study the cause of the observed changes in SAR intensity. Because a reduction of correlation over areas with intensity changes was not observed, we interpreted the intensity changes as not being caused by changes in roughness/structure, but by a change in soil moisture owing to rainfall. An increase in soil moisture ranging from 5% to 20% is the most likely explanation for the increase of intensity. These analyses imply that both intensity and phase information should be used in SAR change detection applications.

  6. Polarization effects and multipolarization SAR

    NASA Technical Reports Server (NTRS)

    Freeman, Anthony

    1992-01-01

    Imaging radar polarimeters are usually implemented using a Synthetic Aperture Radar (SAR) approach to give a high resolution image in two dimensions: range and azimuth. For each pixel in the image a polarimetric SAR gives sufficient information to characterize the polarimetric scattering properties of the imaged area (or target) as seen by the radar. Using a polarimetric SAR system as opposed to a single-polarization SAR system provides significantly more information about the target scattering mechanisms and allows better discrimination between different types of surfaces. In these notes a brief overview of SAR polarimetry is offered. The notes are intended as a text to accompany a lecture on SAR polarimetry as part of an AGARD-NATO course. Covered in the notes are the following: the polarization properties of electromagnetic waves; the concepts of radar scattering and measuring radar backscatter with a SAR; polarization synthesis; scattering matrix, Stokes matrix, and covariance matrix representations of polarimetric SAR data; polarization signature plots; design and calibration of polarimetric SAR systems; polarization filtering for target detection; fitting a simple model to polarimetric SAR measurements of naturally occurring features; and supervised classification of polarimetric SAR data.

  7. Sea bottom topography imaging with SAR

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  8. Bistatic SAR: Proof of Concept.

    SciTech Connect

    Yocky, David A.; Doren, Neall E.; Bacon, Terry A.; Wahl, Daniel E.; Eichel, Paul H.; Jakowatz, Charles V,; Delaplain, Gilbert G.; Dubbert, Dale F.; Tise, Bertice L.; White, Kyle R.

    2014-10-01

    Typical synthetic aperture RADAR (SAR) imaging employs a co-located RADAR transmitter and receiver. Bistatic SAR imaging separates the transmitter and receiver locations. A bistatic SAR configuration allows for the transmitter and receiver(s) to be in a variety of geometric alignments. Sandia National Laboratories (SNL) / New Mexico proposed the deployment of a ground-based RADAR receiver. This RADAR receiver was coupled with the capability of digitizing and recording the signal collected. SNL proposed the possibility of creating an image of targets the illuminating SAR observes. This document describes the developed hardware, software, bistatic SAR configuration, and its deployment to test the concept of a ground-based bistatic SAR. In the proof-of-concept experiments herein, the RADAR transmitter will be a commercial SAR satellite and the RADAR receiver will be deployed at ground level, observing and capturing RADAR ground/targets illuminated by the satellite system.

  9. Geodetic imaging of tectonic deformation with InSAR

    NASA Astrophysics Data System (ADS)

    Fattahi, Heresh

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

  10. Cascades of InSAR in the Cascades - outlook for the use of InSAR and space-based imaging catalogues in a Subduction Zone Observatory

    NASA Astrophysics Data System (ADS)

    Lohman, R. B.

    2015-12-01

    Interferometric synthetic aperture radar (InSAR) has long demonstrated its utility to studies of subduction zone earthquakes, crustal events and volcanic processes, particularly in regions with very good temporal data coverage (e.g., Japan), or arid regions where the timescale of surface change is long compared to the repeat time of the available SAR imagery (e.g., portions of South America). Recently launched and future SAR missions with open data access will increase the temporal sampling rates further over many areas of the globe, resulting in a new ability to lower the detection threshold for earthquakes and, potentially, interseismic motion and transients associated with subduction zone settings. Here we describe some of the anticipated detection abilities for events ranging from earthquakes and slow slip along the subduction zone interface up to landslides, and examine the variations in land use around the circum-Pacific and how that and its changes over time will affect the use of InSAR. We will show the results of an effort to combine Landsat and other optical imagery with SAR data catalogues in the Pacific Northwest to improve the characterization of ground deformation signals, including the identification of "spurious" signals that are not related to true ground deformation. We also describe prospects for working with other communities that are interested in variations in soil moisture and vegetation structure over the same terrain.

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

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

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

  12. Land Cover Mapping Using SENTINEL-1 SAR Data

    NASA Astrophysics Data System (ADS)

    Abdikan, S.; Sanli, F. B.; Ustuner, M.; Calò, F.

    2016-06-01

    In this paper, the potential of using free-of-charge Sentinel-1 Synthetic Aperture Radar (SAR) imagery for land cover mapping in urban areas is investigated. To this aim, we use dual-pol (VV+VH) Interferometric Wide swath mode (IW) data collected on September 16th 2015 along descending orbit over Istanbul megacity, Turkey. Data have been calibrated, terrain corrected, and filtered by a 5x5 kernel using gamma map approach. During terrain correction by using a 25m resolution SRTM DEM, SAR data has been resampled resulting into a pixel spacing of 20m. Support Vector Machines (SVM) method has been implemented as a supervised pixel based image classification to classify the dataset. During the classification, different scenarios have been applied to find out the performance of Sentinel-1 data. The training and test data have been collected from high resolution image of Google Earth. Different combinations of VV and VH polarizations have been analysed and the resulting classified images have been assessed using overall classification accuracy and Kappa coefficient. Results demonstrate that, combining opportunely dual polarization data, the overall accuracy increases up to 93.28% against 73.85% and 70.74% of using individual polarization VV and VH, respectively. Our preliminary analysis points out that dual polarimetric Sentinel-1SAR data can be effectively exploited for producing accurate land cover maps, with relevant advantages for urban planning and management of large cities.

  13. Ultrawideband VHF SAR design and measurements

    NASA Astrophysics Data System (ADS)

    Hellsten, Hans; Froelind, Per-Olov; Gustafsson, Anders; Jonsson, T.; Larsson, Bjoern; Stenstroem, Gunnar; Binder, Bradley T.; Mirkin, Mitchell I.; Ayasli, Serpil

    1994-07-01

    CARABAS, an acronym for `coherent all radio band sensing,' is an airborne, horizontal-polarization SAR operating across the frequency band 20 to 90 MHz, conceived, designed and built by FOA in Sweden. The original motivation for designing such a low frequency system was that a large relative or fractional bandwidth could be achieved at low frequencies. For reasons to be explained, a large fractional bandwidth was considered to be of potential benefit for radar detection in severe clutter environments. A feasibility study of a short wave ultra-wideband radar started at FOA in 1985. Actual construction of the CARABAS system commenced 1987, aircraft integration took place during 1991 and the first radar tests were conducted in early 1992. From the fall of 1992 onwards, field campaigns and evaluation studies have been conducted as a joint effort between FOA and MIT Lincoln Laboratory in the US. This article will focus on experiences concerning foliage penetration with the system. First we touch upon the CARABAS system characteristics, outline the arguments behind a large fractional bandwidth VHF-band SAR approach to foliage penetration, and finally present some early experimental results. We refer to other papers for a fuller explanation of the system, for more details of image calibration, and for results concerning underground imaging.

  14. Application of pixel segmentation to the low rate compression of complex SAR imagery

    SciTech Connect

    Ives, R.W.; Eichel, P.; Magotra, N.

    1998-03-01

    This paper describes a technique to identify pixels within a subregion (chip) of a complex or detected SAR image which are to be losslessly compressed while the remainder of the image is subjected to a high compression ratio. This multi-modal compression is required for the intelligent low rate compression of SAR imagery, which addresses the problem of transmitting massive amounts of high resolution complex SAR data from a remote airborne sensor to a ground station for exploitation by an automatic target recognition (ATR) system, in a real time environment, over a narrow bandwidth. The ATR system results might then be presented to an image analyst who, using the contextual information from the SAR image, makes final target determination.

  15. Characterization of spatial statistics of distributed targets in SAR data. [applied to sea-ice data

    NASA Technical Reports Server (NTRS)

    Rignot, E.; Kwok, R.

    1993-01-01

    A statistical approach to the analysis of spatial statistics in polarimetric multifrequency SAR data, which is aimed at extracting the intrinsic variability of the target by removing variability from other sources, is presented. An image model, which takes into account three sources of spatial variability, namely, image speckle, system noise, and the intrinsic spatial variability of the target or texture, is described. It is shown that the presence of texture increases the image variance-to-mean square ratio and introduces deviations of the image autocovariance function from the expected SAR system response. The approach is exemplified by sea-ice SAR imagery acquired by the Jet Propulsion Laboratory three-frequency polarimetric airborne SAR. Data obtained indicate that, for different sea-ice types, the spatial statistics seem to vary more across frequency than across polarization and the observed differences increase in magnitude with decreasing frequency.

  16. SAR and INSAR Possibilities for the Remote Sensing of Forest Structure (Invited)

    NASA Astrophysics Data System (ADS)

    Hensley, S.; Papathanassiou, K.

    2010-12-01

    SAR and InSAR Possibilities for the Remote Sensing of Forest Structure Scott Hensley† and Kostas Papathanassiou¥ Jet Propulsion Laboratory† and Deutsches Zentrum für Luft- und Raumfahrt¥ Forest structure information is a vital component to carbon cycle understanding and modeling, biodiversity and habitat studies and understanding the effects of anthropogenically induced changes to ecosystems. The biophysical structural parameters of interest vary from application to application and often require extensive field campaigns to obtain measurements that are extremely sparse relative to the Earth’s surface that are covered by forests. The only practical means for obtaining global measures of forest structure is through some form of remote sensing. Regardless, the form of the remote sensing instrument it does not measure the biophysical parameter directly of interest, but usually some parameter that through modeling or an empirical algorithm can be related to the quantity of interest. Synthetic aperture radar and interferometric synthetic aperture radar systems measure parameters that are sensitive to vegetation structure and that can be inverted to give biophysical structural parameters. Synthetic aperture radar systems, in particular fully polarimetric systems, have been developing algorithms for inverting biomass and DBH data for the past 30 years with varying degrees of success. The advent of interferometric systems over the last 20 years has permitted a refinement to both the accuracy and number of biophysical structural parameters that can be sensed by microwave radar systems. This talk will present a overview of how SAR and InSAR systems are sensitive to forest structure and the state of the art in terms of retrieving this information from these system. Our discussion will include multi-baseline, multi-frequency and polarimetric interferometric mapping systems.

  17. AirSWOT: A New Airborne Instrument for Hydrology

    NASA Astrophysics Data System (ADS)

    Rodriguez, E.; Behar, A.; Carswell, J.; Chu, V.; Farquharson, G.; Gleason, C. J.; Hensley, S.; Minear, J. T.; Moller, D.; Pavelsky, T.; Perkovic-Martin, D.; Pitcher, L. H.; Sanchez-Barmetty, M.; Smith, L. C.; Wu, X.

    2013-12-01

    The proposed NASA/CNES/CSA Surface Water and Ocean Topography (SWOT) Mission would provide the first global inventory of storage change in fresh water bodies and river discharge. The SWOT mission would produce elevation maps and imagery of all surface water bodies using Ka-band SAR interferometry. From these data, estimates of surface water extent, stage and slope could be derived, and, in theory, from their temporal variability, river bathymetry and Manning's roughness coefficient can also be estimated, enabling estimates of river discharge. Although significant modeling work and some empirical measurements have been used to validate the feasibility of turning SWOT observables into hydrologic measurements of storage change and discharge, no data have been collected using SWOT-like measurements. To overcome this limitation, a new airborne interferometric system, called AirSWOT, has been developed by Remote Sensing Solutions and integrated, tested, and deployed on the NASA Dryden King Air B200 by the Jet Propulsion Laboratory. As part of the validation of AirSWOT, four data collections were devoted to hydrology targets. The first hydrology target consisted of a large reach of the Sacramento River north of Sacramento, CA. The reach was imaged on consecutive days, coincident with a 1,000 cubic-feet/second release from a dam. Ground data were obtained from HOBO water level loggers and gauges deployed by the USGS. An innovative GPS drifter capable of providing centimeter-level elevation measurements and river slopes was developed by UCLA/JPL and deployed along a significant fraction of the reach. The second target was the Sacramento-San Joaquin Delta region, imaged at low and high tides during the same day. For both targets, APL-UW deployed an airborne instrument suite consisting of an along-track interferometer to measure water surface velocities, a thermal infrared camera to validate measurements of river width, and an experimental lidar system. Finally, a team from

  18. Monitoring deformation at The Geysers geothermal field, California using C-band and X-band Interferometric Synthetic Aperture Radar

    NASA Astrophysics Data System (ADS)

    Vasco, D. W.; Rutqvist, J.; Dobson, P. F.; Oldenburg, C. M.; Ferretti, A.; Rucci, A.; Novali, F.; Garcia, J.; Walters, M.; Hartline, C.

    2012-12-01

    Using two distinct sets of interferometric synthetic aperture radar (InSAR) data and permanent scatterer analysis we are able to resolve deformation at The Geysers geothermal field. The first set of observations utilize archived European Space Agency (ESA) C-band synthetic aperture radar (SAR) data from 1992 through 1999 to image the long-term and large-scale subsidence in the geothermal field. The peak subsidence rate of 51.5 mm/year agrees with previous estimates from leveling and global positioning system observations. Data from a second set of measurements, acquired by a recently tasked TerraSar-X satellite, extend from May 2011 until April 2012 and overlap the C-band data spatially but not temporally. The higher frequency X-band data provides a much higher density of permanent scatters (1122 per square kilometer) than the lower frequency C-band data (12 per square kilometer) over the area surrounding an enhanced geothermal system (EGS) injection well. The EGS injection well is part of an EGS demonstration project in the northern portion of The Geysers field. The X-band InSAR observations are sensitive to some 1 to 2 cm of deformation induced by water injected into the EGS well starting in October 2011. The temporal variation of the deformation is compatible with the displacement history calculated using coupled numerical modeling of the water injection.

  19. Detection of aquifer system compaction and land subsidence using interferometric synthetic aperture radar, Antelope Valley, Mojave Desert, California

    USGS Publications Warehouse

    Galloway, D.L.; Hudnut, K.W.; Ingebritsen, S.E.; Phillips, S.P.; Peltzer, G.; Rogez, F.; Rosen, P.A.

    1998-01-01

    Interferometric synthetic aperture radar (InSAR) has great potential to detect and quantify land subsidence caused by aquifer system compaction. InSAR maps with high spatial detail and resolution of range displacement (??10 mm in change of land surface elevation) were developed for a groundwater basin (~103 km2) in Antelope Valley, California, using radar data collected from the ERS-1 satellite. These data allow comprehensive comparison between recent (1993-1995) subsidence patterns and those detected historically (1926-1992) by more traditional methods. The changed subsidence patterns are generally compatible with recent shifts in land and water use. The InSAR-detected patterns are generally consistent with predictions based on a coupled model of groundwater flow and aquifer system compaction. The minor inconsistencies may reflect our imperfect knowledge of the distribution and properties of compressible sediments. When used in conjunction with coincident measurements of groundwater levels and other geologic information, InSAR data may be useful for constraining parameter estimates in simulations of aquifer system compaction.

  20. Sparsity-driven autofocus for multipass SAR tomography

    NASA Astrophysics Data System (ADS)

    Muirhead, F.; Mulgrew, B.; Woodhouse, I. H.; Greig, D.

    2015-10-01

    Synthetic aperture radar (SAR) systems produce high resolution, two dimensional imaging of areas of environmental interest. SAR interferometry and tomography enables these techniques to extend to three dimensional imaging by exploiting multiple SAR images with diversity in space and time. These techniques require accurate phase information over multiple images as the data is extremely sensitive to deviations from the reference track, therefore to enable interferometry and tomography an accurate autofocus solution is required. This paper investigates phase errors resulting from navigational uncertainties in multipass spotlight SAR imaging and uses techniques from the field of compressive sensing to achieve an autofocus solution. The proposed algorithm builds on previous autofocus work by expanding it to the multipass case and jointly recovers phase errors for all images simultaneously, making it extremely useful for interferometry and tomography techniques. The algorithm described uses pixels that are stable in all SAR images to gain an autofocus solution as these are the pixels that are the focus for analysis using tomography. This is unlike conventional autofocus, which just works on an image-by-image basis. The tools of compressive sensing can be used to concurrently select pixels for bright image elements that are stable and coherent over all images, as these pixels are sparse in the image domain, and calculate the phase errors present in each pass. Using the multipass data after autofocus, height distributions for scatterers in single pixels are determined for simulated forest scenes at X-band. The performance of the autofocus algorithm is examined through numerical simulations and is also applied to real data collected from Selex ES's airborne, X-band, experimental SAR system. The experimental results demonstrate that the algorithm effectively achieves an autofocus solution. By finding the vertical distribution of two scatterers in a single pixel over

  1. Fast interferometric second harmonic generation microscopy

    PubMed Central

    Bancelin, Stéphane; Couture, Charles-André; Légaré, Katherine; Pinsard, Maxime; Rivard, Maxime; Brown, Cameron; Légaré, François

    2016-01-01

    We report the implementation of fast Interferometric Second Harmonic Generation (I-SHG) microscopy to study the polarity of non-centrosymmetric structures in biological tissues. Using a sample quartz plate, we calibrate the spatially varying phase shift introduced by the laser scanning system. Compensating this phase shift allows us to retrieve the correct phase distribution in periodically poled lithium niobate, used as a model sample. Finally, we used fast interferometric second harmonic generation microscopy to acquire phase images in tendon. Our results show that the method exposed here, using a laser scanning system, allows to recover the polarity of collagen fibrils, similarly to standard I-SHG (using a sample scanning system), but with an imaging time about 40 times shorter. PMID:26977349

  2. Focused-laser interferometric position sensor

    SciTech Connect

    Friedman, Stephen J.; Barwick, Brett; Batelaan, Herman

    2005-12-15

    We describe a simple method to measure the position shifts of an object with a range of tens of micrometers using a focused-laser (FL) interferometric position sensor. In this article we examine the effects of mechanical vibration on FL and Michelson interferometers. We tested both interferometers using vibration amplitudes ranging from 0 to 20 {mu}m. Our FL interferometer has a resolution much better than the diffraction grating periodicities of 10 and 14 {mu}m used in our experiments. A FL interferometer provides improved mechanical stability at the expense of spatial resolution. Our experimental results show that Michelson interferometers cannot be used when the vibration amplitude is more than an optical wavelength. The main purpose of this article is to demonstrate that a focused-laser interferometric position sensor can be used to measure the position shifts of an object on a less sensitive, micrometer scale when the vibration amplitude is too large to use a Michelson interferometer.

  3. Dynamics of landfast sea ice near Jangbogo Antarctic Research Station observed by SAR interferometry

    NASA Astrophysics Data System (ADS)

    Lee, H.; Han, H.

    2015-12-01

    Landfast sea ice is a type of sea ice adjacent to the coast and immobile for a certain period of time. It is important to analyze the temporal and spatial variation of landfast ice because it has significant influences on marine ecosystem and the safe operation of icebreaker vessels. However, it has been a difficult task for both remote sensing and in situ observation to discriminate landfast ice from other types of sea ice, such as pack ice, and also to understand the dynamics and internal strss-strain of fast ice. In this study, we identify landfast ice and its annual variation in Terra Nova Bay (74° 37' 4"S, 164° 13' 7"E), East Antarctica, where Jangbogo Antarctic Research Station has recently been constructed in 2014, by using Interferometric Synthetic Aperture Radar (InSAR) technology. We generated 38 interferograms having temporal baselines of 1-9 days out of 62 COSMO-SkyMed SAR images over Terra Nova Bay obtained from December 2010 to January 2012. Landfast ice began to melt in November 2011 when air temperature raised above freezing point but lasted more than two month to the end of the study period in January 2012. No meaningful relationship was found between sea ice extent and wind and current. Glacial strain (~67cm/day) is similar to tidal strain (~40 cm) so that they appear similar in one-day InSAR. As glacial stress is cumulative while tidal stress is oscillatory, InSAR images with weekly temporal baseline (7~9 days) revealed that a consistent motion of Campbell Glacier Tongue (CGT) is pushing the sea ice continuously to make interferometric fringes parallel to the glacier-sea ice contacts. Glacial interferometric fringe is parallel to the glacier-sea ice contact lines while tidal strain should be parallel to the coastlines defined by sea shore and glacier tongue. DDInSAR operation removed the consistent glacial strain leaving tidal strain alone so that the response of fast ice to tide can be used to deduce physical properties of sea ice in various

  4. Interferometric observations of an artificial satellite.

    NASA Technical Reports Server (NTRS)

    Preston, R. A.; Ergas, R.; Hinteregger, H. F.; Knight, C. A.; Robertson, D. S.; Shapiro, I. I.; Whitney, A. R.; Rogers, A. E. E.; Clark, T. A.

    1972-01-01

    Very-long-baseline interferometric observations of radio signals from the TACSAT synchronous satellite, even though extending over only 7 hours, have enabled an excellent orbit to be deduced. Precision in differential delay and delay-rate measurements reached 0.15 nanosecond and 0.05 picosecond per second, respectively. The results from this initial three-station experiment demonstrate the feasibility of using the method for accurate satellite tracking and for geodesy.

  5. Multipulse interferometric frequency-resolved optical gating

    SciTech Connect

    Siders, C.W.; Siders, J.L.W.; Omenetto, F.G.; Taylor, A.J.

    1999-04-01

    The authors review multipulse interferometric frequency-resolved optical gating (MI-FROG) as a technique, uniquely suited for pump-probe coherent spectroscopy using amplified visible and near-infrared short-pulse systems and/or emissive targets, for time-resolving ultrafast phase shifts and intensity changes. Application of polarization-gate MI-FROG to the study of ultrafast ionization in gases is presented.

  6. Analysis of the interferometric Ronchi test.

    PubMed

    Malacara, D

    1990-09-01

    It is well known that the Ronchi test has two equivalent interpretations, Physical, as an interferometer, or geometrical, as if the fringes were just shadows from the fringes on the ruling. The second interpretation is nearly always used in practice because it is simpler. However, the disadvantage is that the irradiance profile of the fringes cannot be calculated with this theory. Here, the interferometric interpretation of the test will be used to obtain the irradiance profile and the sharpness of the fringes.

  7. Comparison of four moderate-size earthquakes in southern California using seismology and InSAR

    USGS Publications Warehouse

    Mellors, R.J.; Magistrale, H.; Earle, P.; Cogbill, A.H.

    2004-01-01

    Source parameters determined from interferometric synthetic aperture radar (InSAR) measurements and from seismic data are compared from four moderate-size (less than M 6) earthquakes in southern California. The goal is to verify approximate detection capabilities of InSAR, assess differences in the results, and test how the two results can be reconciled. First, we calculated the expected surface deformation from all earthquakes greater than magnitude 4 in areas with available InSAR data (347 events). A search for deformation from the events in the interferograms yielded four possible events with magnitudes less than 6. The search for deformation was based on a visual inspection as well as cross-correlation in two dimensions between the measured signal and the expected signal. A grid-search algorithm was then used to estimate focal mechanism and depth from the InSAR data. The results were compared with locations and focal mechanisms from published catalogs. An independent relocation using seismic data was also performed. The seismic locations fell within the area of the expected rupture zone for the three events that show clear surface deformation. Therefore, the technique shows the capability to resolve locations with high accuracy and is applicable worldwide. The depths determined by InSAR agree with well-constrained seismic locations determined in a 3D velocity model. Depth control for well-imaged shallow events using InSAR data is good, and better than the seismic constraints in some cases. A major difficulty for InSAR analysis is the poor temporal coverage of InSAR data, which may make it impossible to distinguish deformation due to different earthquakes at the same location.

  8. Geodetic integration of Sentinel-1A IW data using PSInSAR in Hungary

    NASA Astrophysics Data System (ADS)

    Farkas, Péter; Hevér, Renáta; Grenerczy, Gyula

    2015-04-01

    ESA's latest Synthetic Aperture Radar (SAR) mission Sentinel-1 is a huge step forward in SAR interferometry. With its default acquisition mode called the Interferometric Wide Swath Mode (IW) areas through all scales can be mapped with an excellent return time of 12 days (while only the Sentinel-1A is in orbit). Its operational data policy is also a novelty, it allows scientific users free and unlimited access to data. It implements a new type of ScanSAR mode called Terrain Observation with Progressive Scan (TOPS) SAR. It has the same resolution as ScanSAR but with better signal-to-noise ratio distribution. The bigger coverage is achieved by rotation of the antenna in the azimuth direction, therefore it requires very precise co-registration because even errors under a pixel accuracy can introduce azimuth phase variations caused by differences in Doppler-centroids. In our work we will summarize the benefits and the drawbacks of the IW mode. We would like to implement the processing chain of GAMMA Remote Sensing of such data for mapping surface motion with special attention to the co-registration step. Not only traditional InSAR but the advanced method of Persistent Scatterer InSAR (PSInSAR) will be performed and presented as well. PS coverage, along with coherence, is expected to be good due to the small perpendicular and temporal baselines. We would also like to integrate these measurements into national geodetic networks using common reference points. We have installed trihedral corner reflectors at some selected sites to aid precise collocation. Thus, we aim to demonstrate that Sentinel-1 can be effectively used for surface movement detection and monitoring and it can also provide valuable information for the improvement of our networks.

  9. Long-range ground deformation monitoring by InSAR analysis

    NASA Astrophysics Data System (ADS)

    Rokugawa, S.; Nakamura, T.

    2015-11-01

    InSAR (Interferometric Synthetic Aperture Radar) analysis is an effective technique to map 3-dimensional surface deformation with high spatial resolution. The aim of this study was to evaluate the capability of InSAR analysis when applied to ground monitoring of an environmental disaster. We performed a time series InSAR analysis using ENVISAT/ASAR and ALOS/PALSAR data and commercial software to investigate subsidence around the Kanto District of Japan. We also investigated techniques for efficient early detection of landslides in Kyushu using time series analysis that incorporated synthetic aperture radar (SAR) images. ENVISAT/ASAR data acquired from 2003-2010 and ALOS/PALSAR data acquired from 2006-2011 were used to detect poorly expressed geomorphological deformation by conducting time series analyses of periodically acquired SAR data. In addition, to remove noise caused by geographical feature stripes or phase retardation, we applied median filtering, histogram extraction processing, and clarification of the displacement with a Laplacian filter. The main functions of the InSAR time series analysis are the calculation of phase differences between two images and the inversion with smoothness constraint for the estimation of deformation along the line of sight. The results enabled us to establish criteria for the selection of suitable InSAR data pairs, and provided the final error estimation of the derived surface deformation. The results of the analysis in the Kanto District suggested that localized areas of uplift and subsidence have occurred at irregular intervals in this area. Furthermore, the method offers the possibility of early warning of environmental disasters such as landslide and abrupt subsidence. Our results confirm the effectiveness of InSAR analysis for the monitoring of ground deformation over wide areas via the detection of localized subsidence and landslides.

  10. A time series deformation estimation in the NW Himalayas using SBAS InSAR technique

    NASA Astrophysics Data System (ADS)

    Kumar, V.; Venkataraman, G.

    2012-12-01

    A time series land deformation studies in north western Himalayan region has been presented in this study. Synthetic aperture radar (SAR) interferometry (InSAR) is an important tool for measuring the land displacement caused by different geological processes [1]. Frequent spatial and temporal decorrelation in the Himalayan region is a strong impediment in precise deformation estimation using conventional interferometric SAR approach. In such cases, advanced DInSAR approaches PSInSAR as well as Small base line subset (SBAS) can be used to estimate earth surface deformation. The SBAS technique [2] is a DInSAR approach which uses a twelve or more number of repeat SAR acquisitions in different combinations of a properly chosen data (subsets) for generation of DInSAR interferograms using two pass interferometric approach. Finally it leads to the generation of mean deformation velocity maps and displacement time series. Herein, SBAS algorithm has been used for time series deformation estimation in the NW Himalayan region. ENVISAT ASAR IS2 swath data from 2003 to 2008 have been used for quantifying slow deformation. Himalayan region is a very active tectonic belt and active orogeny play a significant role in land deformation process [3]. Geomorphology in the region is unique and reacts to the climate change adversely bringing with land slides and subsidence. Settlements on the hill slopes are prone to land slides, landslips, rockslides and soil creep. These hazardous features have hampered the over all progress of the region as they obstruct the roads and flow of traffic, break communication, block flowing water in stream and create temporary reservoirs and also bring down lot of soil cover and thus add enormous silt and gravel to the streams. It has been observed that average deformation varies from -30.0 mm/year to 10 mm/year in the NW Himalayan region . References [1] Massonnet, D., Feigl, K.L.,Rossi, M. and Adragna, F. (1994) Radar interferometry mapping of

  11. Extending interferometric synthetic aperture radar measurements from one to two dimensions

    NASA Astrophysics Data System (ADS)

    Bechor, Noah

    Interferometric synthetic aperture radar (InSAR), a very effective technique for measuring crustal deformation, provides measurements in only one dimension, along the radar line of sight. Imaging radar measurements from satellite-based systems are sensitive to both vertical and across-track displacements, but insensitive to along-track displacement. Multiple observations can resolve the first two components, but the along-track component remains elusive. The best existing method to obtain the along-track displacement involves pixel-level azimuth cross-correlation. The measurements are quite coarse (typically 15 cm precision), and they require large computation times. In contrast, across-track and vertical InSAR measurements can reach centimeter-level precision and are readily derived. We present a new method to extract along-track displacements from InSAR data. The new method, multiple aperture InSAR (MAI), is based on split-beam processing of InSAR data to create forward- and backward-looking interferograms. The phase difference between the two modified interferograms provides the along-track displacement component. Thus, from each conventional InSAR pair we extract two components of the displacement vector: one along the line of sight, the other in the along-track direction. Multiple MAI observations, either at two look angles or from the ascending and descending radar passes, then yield the three-dimensional displacement field. We analyze precision of our method by comparing our solution to GPS and offset-derived along-track displacements from interferograms of the M7.1 1999, Hector Mine earthquake. The RMS error between GPS displacements and our results ranges from 5 to 8.8cm. Our method is consistent with along-track displacements derived by pixel-offsets, themselves limited to 12-15cm precision. The theoretical MAI precision depends on SNR and coherence. For SNR=100 the expected precision is 3, 11cm for coherence of 0.8, 0.4, respectively. Finally, we

  12. On the COSMO-SkyMed Exploitation for Interferometric DEM Generation

    NASA Astrophysics Data System (ADS)

    Teresa, C. M.; Raffaele, N.; Oscar, N. D.; Fabio, B.

    2011-12-01

    DEM products for Earth observation space-borne applications are being to play a role of increasing importance due to the new generation of high resolution sensors (both optical and SAR). These new sensors demand elevation data for processing and, on the other hand, they provide new possibilities for DEM generation. Till now, for what concerns interferometric DEM, the Shuttle Radar Topography Mission (SRTM) has been the reference product for scientific applications all over the world. SRTM mission [1] had the challenging goal to meet the requirements for a homogeneous and reliable DEM fulfilling the DTED-2 specifications. However, new generation of high resolution sensors (including SAR) pose new requirements for elevation data in terms of vertical precision and spatial resolution. DEM are usually used as ancillary input in different processing steps as for instance geocoding and Differential SAR Interferometry. In this context, the recent SAR missions of DLR (TerraSAR-X and TanDEM-X) and ASI (COSMO-SkyMed) can play a promising role thanks to their high resolution both in space and time. In particular, the present work investigates the potentialities of the COSMO/SkyMed (CSK) constellation for ground elevation measurement with particular attention devoted to the impact of the improved spatial resolution wrt the previous SAR sensors. The recent scientific works, [2] and [3], have shown the advantages of using CSK in the monitoring of terrain deformations caused by landslides, earthquakes, etc. On the other hand, thanks to the high spatial resolution, CSK appears to be very promising in monitoring man-made structures, such as buildings, bridges, railways and highways, thus enabling new potential applications (urban applications, precise DEM, etc.). We present results obtained by processing both SPOTLIGHT and STRIPMAP acquisitions through standard SAR Interferometry as well as multi-pass interferometry [4] with the aim of measuring ground elevation. Acknowledgments

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

    NASA Astrophysics Data System (ADS)

    Werner, Marian U.

    1993-05-01

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

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

    NASA Technical Reports Server (NTRS)

    Werner, Marian U.

    1993-01-01

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

  15. Hospital Preparedness and SARS

    PubMed Central

    Wallington, Tamara; Rutledge, Tim; Mederski, Barbara; Rose, Keith; Kwolek, Sue; McRitchie, Donna; Ali, Azra; Wolff, Bryan; White, Diane; Glassman, Edward; Ofner, Marianna; Low, Don E.; Berger, Lisa; McGeer, Allison; Wong, Tom; Baron, David; Berall, Glenn

    2004-01-01

    On May 23, 2003, Toronto experienced the second phase of a severe acute respiratory syndrome (SARS) outbreak. Ninety cases were confirmed, and >620 potential cases were managed. More than 9,000 persons had contact with confirmed or potential case-patients; many required quarantine. The main hospital involved during the second outbreak was North York General Hospital. We review this hospital’s response to, and management of, this outbreak, including such factors as building preparation and engineering, personnel, departmental workload, policies and documentation, infection control, personal protective equipment, training and education, public health, management and administration, follow-up of SARS patients, and psychological and psychosocial management and research. We also make recommendations for other institutions to prepare for future outbreaks, regardless of their origin. PMID:15200807

  16. The Danish SAR system - Design and initial tests

    NASA Technical Reports Server (NTRS)

    Madsen, Soren N.; Christensen, Erik L.; Skou, Niels; Dall, Jorgen

    1991-01-01

    In January 1986, the design of a high-resolution airborne C-band SAR started at the Electromagnetics Institute of the Technical University of Denmark. The initial system test flights took place in November and December 1989. The authors describe the design of the system, its implementation, and its performance. They show how digital technology has been utilized to realize a very flexible radar with variable resolution, swath-width, and imaging geometry. The motion-compensation algorithms implemented to obtain the high resolution and the special features built into the system to ensure proper internal calibration are outlined. The data processing system, developed for image generation and quality assurance, is sketched, with special emphasis on the flexibility of the system. Sample images and a preliminary performance evaluation are presented, demonstrating that the design goals have been met. The ongoing system upgrades and the planned scientific utilization of the C-band SAR are described.

  17. Unsupervised segmentation of polarimetric SAR data using the covariance matrix

    NASA Technical Reports Server (NTRS)

    Rignot, Eric J. M.; Chellappa, Rama; Dubois, Pascale C.

    1992-01-01

    A method for unsupervised segmentation of polarimetric synthetic aperture radar (SAR) data into classes of homogeneous microwave polarimetric backscatter characteristics is presented. Classes of polarimetric backscatter are selected on the basis of a multidimensional fuzzy clustering of the logarithm of the parameters composing the polarimetric covariance matrix. The clustering procedure uses both polarimetric amplitude and phase information, is adapted to the presence of image speckle, and does not require an arbitrary weighting of the different polarimetric channels; it also provides a partitioning of each data sample used for clustering into multiple clusters. Given the classes of polarimetric backscatter, the entire image is classified using a maximum a posteriori polarimetric classifier. Four-look polarimetric SAR complex data of lava flows and of sea ice acquired by the NASA/JPL airborne polarimetric radar (AIRSAR) are segmented using this technique. The results are discussed and compared with those obtained using supervised techniques.

  18. Agile waveforms for joint SAR-GMTI processing

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  19. Velocity estimation of slow moving targets in AT-InSAR systems

    NASA Astrophysics Data System (ADS)

    Budillon, A.; Pascazio, V.; Schirinzi, G.

    2007-10-01

    Along Track Interferometric Synthetic Aperture Radar (AT-InSAR) systems use more than one SAR antennas (typically two), mounted on the same platform and displaced along the platform moving direction, to detect slow ground moving targets. The phase of the ATI signal is related to the target motion parameters and may thus be used to estimate the radial velocity. In this paper we approach the velocity estimation problem using statistical techniques based on the statistical distribution of the measured interferometric phases. We analyze the radial velocity estimation with respect to ATI system parameters, such as velocity values, the signal to clutter ratio (SCR), the clutter to noise ratio (CNR), considering a deterministic target whose velocity is estimated using a Gaussian model. This model allows to take into account the lack of knowledge of the target radar cross section (RCS) values and provides an analytical form for the interferometric phase probability density function. Simulations results show that the adoption of Maximum Likelihood (ML) techniques, to perform a joint estimation of velocity and SCR, and multi-channel configurations, to overcome ambiguities problems, provide very good velocity estimation accuracy.

  20. Monitoring of surface deformation in open pit mine using DInSAR time-series: a case study in the N5W iron mine (Carajás, Brazil) using TerraSAR-X data

    NASA Astrophysics Data System (ADS)

    Mura, José C.; Paradella, Waldir R.; Gama, Fabio F.; Santos, Athos R.; Galo, Mauricio; Camargo, Paulo O.; Silva, Arnaldo Q.; Silva, Guilherme G.

    2014-10-01

    We present an investigation of surface deformation using Differential SAR Interferometry (DInSAR) time-series carried out in an active open pit iron mine, the N5W, located in the Carajás Mineral Province (Brazilian Amazon region), using 33 TerraSAR-X (TSX-1) scenes. This mine has presented a historical of instability and surface monitoring measurements over sectors of the mine (pit walls) have been done based on ground based radar. Two complementary approaches were used: the standard DInSAR configuration, as an early warning of the slope instability conditions, and the DInSAR timeseries analysis. In order to decrease the topographic phase error a high resolution DEM was generated based on a stereo GeoEye-1 pair. Despite the fact that a DinSAR contains atmospheric and topographic phase artifacts and noise, it was possible to detect deformation in some interferometric pairs, covering pit benches, road ramps and waste piles. The timeseries analysis was performed using the 31 interferometric pairs, which were selected based on the highest mean coherence of a stack of 107 interferograms, presenting less phase unwrapping errors. The time-series deformation was retrieved by the Least-Squares (LS) solution using an extension of the Singular Value Decomposition (SVD), with a set of additional weighted constrain on the acceleration deformation. The atmospheric phase artifacts were filtered in the space-time domain and the DEM height errors were estimated based on the normal baseline diversity. The DInSAR time-series investigation showed good results for monitoring surface displacement in the N5W mine located in a tropical rainforest environment, providing very useful information about the ground movement for alarm, planning and risk assessment.

  1. SAR peculiarities, ambiguities and constraints

    NASA Astrophysics Data System (ADS)

    Keydel, Wolfgang

    1992-08-01

    A synthetic aperture radar (SAR) is basically a coherent scatterometer that employs a coherent real aperture radar with highly sophisticated data evaluation and image processing capabilities. Therefore, the coherence of the system is very important; furthermore, the keypoints for SAR are data storage, evaluation, and processing. These facts entail peculiarities of SAR and special ambiguities which are different from those arising with real aperture radar (RAR). The objective of this paper is to point out the special peculiarities and ambiguities of SAR in comparison to the corresponding properties of RAR. Main topics in this connection are as follows: basic peculiarities like range dependency of signal to noise ratio; azimuth resolution; influence of platform velocity; range and azimuth ambiguities; pulse repetition frequency limitations; velocity effects; and phase error influence, on SAR-image, that can cause motion compensation problems. All these effects will be explained together with different contrast-equations between the target and clutter signals of SAR and RAR.

  2. GIAnT - Generic InSAR Analysis Toolbox

    NASA Astrophysics Data System (ADS)

    Agram, P.; Jolivet, R.; Riel, B. V.; Simons, M.; Doin, M.; Lasserre, C.; Hetland, E. A.

    2012-12-01

    We present a computing framework for studying the spatio-temporal evolution of ground deformation from interferometric synthetic aperture radar (InSAR) data. Several open-source tools including Repeat Orbit Interferometry PACkage (ROI-PAC) and InSAR Scientific Computing Environment (ISCE) from NASA-JPL, and Delft Object-oriented Repeat Interferometric Software (DORIS), have enabled scientists to generate individual interferograms from raw radar data with relative ease. Numerous computational techniques and algorithms that reduce phase information from multiple interferograms to a deformation time-series have been developed and verified over the past decade. However, the sharing and direct comparison of products from multiple processing approaches has been hindered by - 1) absence of simple standards for sharing of estimated time-series products, 2) use of proprietary software tools with license restrictions and 3) the closed source nature of the exact implementation of many of these algorithms. We have developed this computing framework to address all of the above issues. We attempt to take the first steps towards creating a community software repository for InSAR time-series analysis. To date, we have implemented the short baseline subset algorithm (SBAS), NSBAS and multi-scale interferometric time-series (MInTS) in this framework and the associated source code is included in the GIAnT distribution. A number of the associated routines have been optimized for performance and scalability with large data sets. Some of the new features in our processing framework are - 1) the use of daily solutions from continuous GPS stations to correct for orbit errors, 2) the use of meteorological data sets to estimate the tropospheric delay screen and 3) a data-driven bootstrapping approach to estimate the uncertainties associated with estimated time-series products. We are currently working on incorporating tidal load corrections for individual interferograms and propagation of

  3. Circular SAR GMTI

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  4. Airborne Interferometry using GNSS Reflections for Surface Level Estimation

    NASA Astrophysics Data System (ADS)

    Semmling, Maximilian; Beyerle, Georg; Schön, Steffen; Stosius, Ralf; Gerber, Thomas; Beckheinrich, Jamila; Markgraf, Markus; Ge, Maorong; Wickert, Jens

    2013-04-01

    The interferometric use of GNSS reflections for ocean altimetry can fill the gap in coverage of ocean observations. Today radar altimeters are used for large scale ocean observations to monitor e.g. global sea level change or circulation processes like El Niño. Spacial and temporal resolution of a single radar altimeter, however, is insufficient to observe mesoscale ocean phenomena like large oceanic eddies that are important indicators of climate change. The high coverage expected for a spaceborne altimeter based on GNSS reflections stimulated investigations on according interferometric methods. Several airborne experiments have been conducted using code observations. Carrier observations have a better precision but are severely affected by noise and have mostly been used in ground-based experiments. A new interferometric approach is presented using carrier observations for airborne application. Implementing a spectral retrieval noise reduction is achieved. A flight experiment was conducted with a Zeppelin airship on 2010/10/12 over Lake Constance at the border between Austria, Germany and Switzerland. The lake surface with an area of 536km2 is suitable for altimetric study as its decimeter range Geoid undulations are well-known. Three GNSS receiver were installed on the airship. A Javad Delta receiver recording direct signals for navigation. The DLR G-REX receiver recording reflected signals for scatterometry and the GORS (GNSS Occultation Reflectometry Scatterometry) receiver recording direct and reflected signals for interferometry. The airship's trajectory is determined from navigation data with a precision better than 10cm using regional augmentation. This presentation focuses on the interferometric analysis of GORS observations. Ray tracing calculations are used to model the difference of direct and reflected signals' path. Spectral retrieval is applied to determine Doppler residuals of modelled path difference and interferometric observations. Lake level

  5. Development and Validation of New Advanced Ocean Altimetry Products From Cryosat-2 in Conventional and in SAR Mode

    NASA Astrophysics Data System (ADS)

    Cotton, D.; Gommenginger, C.; Andersen, O. B.; Boy, F.; Cancet, M.; Egido, A.; Fernandes, J.; Moreau, T.; Naeije, M.; Garcia, P.; Dinardo, S.; Benveniste, J.

    2013-12-01

    The ESA CryoSat-2 mission is the first space mission to carry a radar altimeter that can operate in Synthetic Aperture Radar (SAR) mode, as well as the more conventional Low Rate Mode (LRM), and also the SAR Interferometric mode (SARIN). Although the prime mission objective of CryoSat-2 is to monitor land and marine ice, the SAR mode capability of the CryoSat-2 SIRAL altimeter also presents the opportunity of demonstrating significant potential benefits of SAR altimetry for ocean applications. Expected performance enhancements of SAR mode include improved range precision, finer along track spatial resolution, and an improved ability to provide measurements close to the coast. The 'Cryosat Plus for Oceans' (CP4O) project is supported by ESA under the Support To Science Element Programme. CP4O started in June 2012, and will continue to June 2014. The objectives of CP4O are: to build a sound scientific basis for new scientific and operational applications of CryoSat-2 data over the open ocean, polar ocean, coastal seas and for sea-floor mapping. to generate and evaluate new methods and products that will enable the full exploitation of the capabilities of the CryoSat-2 SIRAL altimeter, and extend their application beyond the initial mission objectives. to ensure that the scientific return of the CryoSat-2 mission is maximised. This work is being carried out within four sub-themes: Open Ocean Altimetry, Coastal Zone Altimetry, Polar Ocean Altimetry, and Sea Floor Altimetry. In this presentation we provide a detailed assessment of the capability of SAR altimeter data to provide improved oceanographic measurements over the open ocean, coastal ocean and polar ocean. We describe different processing schemes applied to Cryosat-2 SAR mode data, to carry out full resolution SAR processing and SAR mode retracking, and to construct LRM-type altimeter waveforms from the SAR bursts, - so called Reduced SAR mode (RDSAR). The latter processing is important to determine if it is

  6. Revising Vegetation Scattering Theories: Adding A Rotated Dihedral Double Bounce Scattering To Explain Cross-Polarimetric SAR Observations Over Wetlands

    NASA Astrophysics Data System (ADS)

    Hong, Sang-Hoon; Wdowinski, Shimon

    2012-01-01

    Common vegetation scattering theories indicate that short wavelength Synthetic Aperture Radar (SAR) observations (X- and C-band) measure mainly vegetation canopies as the short-wavelength radar signal interacts mostly with upper sections of the vegetation. Furthermore, these theories also suggest that SAR cross- polarization (cross-pol) observations reflect only volume scattering. Consequently most SAR decomposition techniques assume that the cross-pol signal represents solely volume scattering. However, short-wavelength and cross-pol observations from the Everglades wetlands, south Florida, suggest that a significant portion of the SAR signal scatters from the surface and not only from the upper sections of the vegetation. The indication for surface scattering in wetland environment is derived from phase observable processed using interferometric techniques. The interferometric SAR (InSAR) observations reveal coherent phase signal in all polarizations and all wavelengths, reflecting water level changes beneath the vegetation. This coherent phase signal cannot be explained by neither volume scattering nor radar signal interaction with the upper sections of the vegetations, because canopies and branches are frequently move by wind. The only way that such coherent signal can be maintained and represents surface water level changes is when a multiple bounce from the vegetation and surface occurs. The simplest multi-bounce scattering mechanism that generate cross-pol signal occurs by rotated dihedrals. Thus, we use the rotated dihedral mechanism to explain the InSAR wetland observations and to revise the current vegetation scattering theories to accounts also for double bounce component in cross-pol observations.

  7. The backscattering characteristics of wetland vegetation and water-level changes detection using multi-mode SAR: A case study

    NASA Astrophysics Data System (ADS)

    Zhang, Meimei; Li, Zhen; Tian, Bangsen; Zhou, Jianmin; Tang, Panpan

    2016-03-01

    A full understanding of the backscattering characteristics of wetlands is necessary for the analysis of the hydrological conditions. In this study, a temporal set of synthetic aperture radar (SAR) imagery, acquired at different frequencies, polarizations and incidence angles over the coastal wetlands of the Liaohe River Delta, China, were used to characterize seasonal variations in radar backscattering coefficient for reed marshes and rice fields. The combination of SAR backscattering intensity and an optical-based normalized difference vegetation index (NDVI) for long time series can provide additional insight into vegetation structural and its hydrological states. After identifying the factors that induce the backscattering and scattering mechanism changes, detailed analysis of L-band ALOS PALSAR interferometric SAR (InSAR) imagery was conducted to study water-level changes under different environmental conditions. In addition, ENVISAT altimetry was used to validate the accuracy of the water-level changes estimated using the InSAR technique-this is an effective tool instead of sparsely distributed gauge stations for the validation. Our study demonstrates that L-band SAR data with horizontal polarization is particularly suitable for the extraction of water-level changes in the study area; however, vertically-polarized C-band data may also be useful where the density of herbaceous vegetation is low at the initial stage. It is also shown that integrated analysis of the backscattering mechanism and interferometric characteristics using multi-mode SAR can considerably enhance the reliability of the water-level retrieval scheme and better capture the spatial distribution of hydrological patterns.

  8. Preliminary results of ESA Category-1 Project 5834 "Application of DInSAR technique to areas of active ground deformations"

    NASA Astrophysics Data System (ADS)

    Massa, B.; D'Auria, L.

    2009-04-01

    We have established a processing chain of Synthetic Aperture Radar (SAR) data for identification and parametrisation of deformation sources in areas of active ground deformation (e.g. seismogenic areas, volcanic districts). SAR data from European Space Agency (ESA) satellites ERS-2 and ENVISAT are used. SAR and InSAR data processing LEVEL 0 SAR data are focussed to Single Look Complex (SLC) through ROI_PAC (Copyright 2002-2008, Caltech/Jet Propulsion Laboratory). We perform an advanced data processing using Doris (Kampes and Usai, 1999) a single program that can do most common steps of the interferometric radar processing starting from SLC data to generation of interferometric products and geocoding. Unwrapping of interferometric phase is performed using the public domain software snaphu (Chen and Zebker, 2001). Modeling of deformation sources We propose a novel inversion approach base on non-linear inversion. The forward modeling is provided by the semi-analytic deformation model for point sources and finite faults. The parameters of the fault (center position, width, height, rake and seismic moment) are inverted using a combination of non-linear optimization algorithms (as Monte-Carlo, Nelder&Mead Simplex and Simulated Annealing). The misfit function defined for the optimization is based on the L2 norm of the error weighted by the coherence of the considered spatial point. Test datasets To test our modeling procedure we chose three different study areas, refer to mainly strike-slip seismogenic sources with different orientation to respect satellite Line Of Sight (LOS): December 26 2003 Iranian earthquake (Bam e.), data from both ascending and descending passes of ENVISAT ASAR narrow swath IS2 (RAW and SLCs); August 17 1999 Turkey earthquake (Izmit e.), data from both ascending and descending passes of ERS-2 AMI SAR (SLCs); June 17-21 2000 Iceland earthquakes, data from both ascending and descending passes of ERS-2 AMI SAR (SLCs). Tests carried over real

  9. Wetland InSAR

    NASA Astrophysics Data System (ADS)

    Wdowinski, S.; Kim, S.; Amelung, F.; Dixon, T.

    2006-12-01

    Wetlands are transition zones where the flow of water, the nutrient cycling, and the sun energy meet to produce a unique and very productive ecosystem. They provide critical habitat for a wide variety of plant and animal species, including the larval stages of many ocean fish. Wetlands also have a valuable economical importance, as they filter nutrients and pollutants from fresh water used by human and provide aquatic habitats for outdoor recreation, tourism, and fishing. Globally, many such regions are under severe environmental stress, mainly from urban development, pollution, and rising sea level. However, there is increasing recognition of the importance of these habitats, and mitigation and restoration activities have begun in a few regions. A key element in wetlands conservation, management, and restoration involves monitoring its hydrologic system, as the entire ecosystem depends on its water supply. Heretofore, hydrologic monitoring of wetlands are conducted by stage (water level) stations, which provide good temporal resolution, but suffer from poor spatial resolution, as stage station are typically distributed several, or even tens of kilometers, from one another. Wetland application of InSAR provides the needed high spatial resolution hydrological observations, complementing the high temporal resolution terrestrial observations. Although conventional wisdom suggests that interferometry does not work in vegetated areas, several studies have shown that both L- and C-band interferograms with short acquisition intervals (1-105 days) can maintain excellent coherence over wetlands. In this study we explore the usage of InSAR for detecting water level changes in various wetland environments around the world, including the Everglades (south Florida), Louisiana Coast (southern US), Chesapeake Bay (eastern US), Pantanal (Brazil), Okavango Delta (Botswana), and Lena Delta (Siberia). Our main study area is the Everglades wetland (south Florida), which is covered by

  10. Improving terrain height estimates from RADARSAT interferometric measurements

    SciTech Connect

    Thompson, P.A.; Eichel, P.H.; Calloway, T.M.

    1998-03-01

    The authors describe two methods of combining two-pass RADAR-SAT interferometric phase maps with existing DTED (digital terrain elevation data) to produce improved terrain height estimates. The first is a least-squares estimation procedure that fits the unwrapped phase data to a phase map computed from the DTED. The second is a filtering technique that combines the interferometric height map with the DTED map based on spatial frequency content. Both methods preserve the high fidelity of the interferometric data.

  11. InSAR observations of the 2009 Racha earthquake, Georgia

    NASA Astrophysics Data System (ADS)

    Nikolaeva, Elena; Walter, Thomas R.

    2016-09-01

    Central Georgia is an area strongly affected by earthquake and landslide hazards. On 29 April 1991 a major earthquake (Mw  =  7.0) struck the Racha region in Georgia, followed by aftershocks and significant afterslip. The same region was hit by another major event (Mw  =  6.0) on 7 September 2009. The aim of the study reported here was to utilize interferometric synthetic aperture radar (InSAR) data to improve knowledge about the spatial pattern of deformation due to the 2009 earthquake. There were no actual earthquake observations by InSAR in Georgia. We considered all available SAR data images from different space agencies. However, due to the long wavelength and the frequent acquisitions, only the multi-temporal ALOS L-band SAR data allowed us to produce interferograms spanning the 2009 earthquake. We detected a local uplift around 10 cm (along the line-of-sight propagation) in the interferogram near the earthquake's epicenter, whereas evidence of surface ruptures could not be found in the field along the active thrust fault. We simulated a deformation signal which could be created by the 2009 Racha earthquake on the basis of local seismic records and by using an elastic dislocation model. We compared our modeled fault surface of the September 2009 with the April 1991 Racha earthquake fault surfaces and identify the same fault or a sub-parallel fault of the same system as the origin. The patch that was active in 2009 is just adjacent to the 1991 patch, indicating a possible mainly westward propagation direction, with important implications for future earthquake hazards.

  12. Permanent Scatterer InSAR Analysis and Validation in the Gulf of Corinth

    PubMed Central

    Elias, Panagiotis; Kontoes, Charalabos; Papoutsis, Ioannis; Kotsis, Ioannis; Marinou, Aggeliki; Paradissis, Dimitris; Sakellariou, Dimitris

    2009-01-01

    The Permanent Scatterers Interferometric SAR technique (PSInSAR) is a method that accurately estimates the near vertical terrain deformation rates, of the order of ∼1 mm year-1, overcoming the physical and technical restrictions of classic InSAR. In this paper the method is strengthened by creating a robust processing chain, incorporating PSInSAR analysis together with algorithmic adaptations for Permanent Scatterer Candidates (PSCs) and Permanent Scatterers (PSs) selection. The processing chain, called PerSePHONE, was applied and validated in the geophysically active area of the Gulf of Corinth. The analysis indicated a clear subsidence trend in the north-eastern part of the gulf, with the maximum deformation of ∼2.5 mm year-1 occurring in the region north of the Gulf of Alkyonides. The validity of the results was assessed against geophysical/geological and geodetic studies conducted in the area, which include continuous seismic profiling data and GPS height measurements. All these observations converge to the same deformation pattern as the one derived by the PSInSAR technique. PMID:22389587

  13. Permanent Scatterer InSAR Analysis and Validation in the Gulf of Corinth.

    PubMed

    Elias, Panagiotis; Kontoes, Charalabos; Papoutsis, Ioannis; Kotsis, Ioannis; Marinou, Aggeliki; Paradissis, Dimitris; Sakellariou, Dimitris

    2009-01-01

    The Permanent Scatterers Interferometric SAR technique (PSInSAR) is a method that accurately estimates the near vertical terrain deformation rates, of the order of ∼1 mm year(-1), overcoming the physical and technical restrictions of classic InSAR. In this paper the method is strengthened by creating a robust processing chain, incorporating PSInSAR analysis together with algorithmic adaptations for Permanent Scatterer Candidates (PSCs) and Permanent Scatterers (PSs) selection. The processing chain, called PerSePHONE, was applied and validated in the geophysically active area of the Gulf of Corinth. The analysis indicated a clear subsidence trend in the north-eastern part of the gulf, with the maximum deformation of ∼2.5 mm year(-1) occurring in the region north of the Gulf of Alkyonides. The validity of the results was assessed against geophysical/geological and geodetic studies conducted in the area, which include continuous seismic profiling data and GPS height measurements. All these observations converge to the same deformation pattern as the one derived by the PSInSAR technique.

  14. Water vapor retrieval by LEO and GEO SAR: techniques and performance evaluation.

    NASA Astrophysics Data System (ADS)

    Fermi, Alessandro; Silvio Marzano, Frank; Monti Guarnieri, Andrea; Pierdicca, Nazzareno; Realini, Eugenio; Venuti, Giovanna

    2016-04-01

    The millimetric sensitivity of SAR interferometry has been proved fruitful in estimating water-vapor maps, that can then be processed into higher level ZWD and PWV products. In the paper, we consider two different SAR surveys: Low Earth Orbiting (LEO) SAR, like ESA Sentinel-1, and Geosynchronous Earth Orbiting SAR. The two system are complementary, where LEO coverage is world-wide, while GEO is regional. On the other hand, LEO revisit is daily-to weekly, whereas GEO provides images in minutes to hours. Finally, LEO synthetic aperture is so short, less than a second, that the water-vapor is mostly frozen, whereas in the long GEO aperture the atmospheric phase screen would introduce a total decorrelation, if not compensated for. In the paper, we first review the Differential Interferometric techniques to get differential delay maps - to be then converted into water-vapor products, and then evaluate the quality in terms of geometric resolution, sensitivity, percentage of scene coverage, revisit, by referring to L and C band system, for both LEO and GEO. Finally, we discuss an empirical model for time-space variogram, and show a preliminary validation by campaign conducted with Ground Based Radar, as a proxy of GEO-SAR, capable of continuous scanning wide areas (up to 15 km) with metric resolution.

  15. Deformation monitoring in Hanyuan reservoir resettlement of Pubugou Hydropower Station using PS-InSAR

    NASA Astrophysics Data System (ADS)

    He, Min; He, Xiufeng

    2011-10-01

    Interferometric synthetic aperture radar (InSAR) is a very effective technique for measuring surface deformation, but the temporal and geometrical decorrelation and atmospheric disturbances can strongly compromise the accuracy of the results. Persistent scatterer InSAR (PS-InSAR) overcomes the decorrelation and atmospheric disturbances problem by identifying resolution elements whose echo is dominated by a single scatterer in a series of interferograms. The results obtained by PS-InSAR technique are not the field deformation information but persistent scatterers deformation. In this paper, PS-InSAR is used to investigate surface deformation caused by landslide hazards in Hanyuan reservoir resettlement, China. The subsidence map derived from Envisat ASAR data between May 2008 and Oct 2009 reveals the spatial extent of the deformations and subsidence velocity. The experimental results show that there are instable areas which are located in the Middle of new Hanyuan county. The average deformation rate of the instable areas is over - 20mm. The Upper right and Lower left of new Hanyuan county are relatively stable.

  16. Multiscale InSAR Time Series (MInTS) analysis of surface deformation

    NASA Astrophysics Data System (ADS)

    Hetland, E. A.; Muse, P.; Simons, M.; Lin, Y. N.; Agram, P. S.; DiCaprio, C. J.

    2011-12-01

    We present a new approach to extracting spatially and temporally continuous ground deformation fields from interferometric synthetic aperture radar (InSAR) data. We focus on unwrapped interferograms from a single viewing geometry, estimating ground deformation along the line-of-sight. Our approach is based on a wavelet decomposition in space and a general parametrization in time. We refer to this approach as MInTS (Multiscale InSAR Time Series). The wavelet decomposition efficiently deals with commonly seen spatial covariances in repeat-pass InSAR measurements, such that coefficients of the wavelets are essentially spatially uncorrelated. Our time-dependent parametrization is capable of capturing both recognized and unrecognized processes, and is not arbitrarily tied to the times of the SAR acquisitions. We estimate deformation in the wavelet-domain, using a cross-validated, regularized least-squares inversion. We include a model-resolution-based regularization, in order to more heavily damp the model during periods of sparse SAR acquisitions, compared to during times of dense acquisitions. To illustrate the application of MInTS, we consider a catalog of 92 ERS and Envisat interferograms, spanning 16 years, in the Long Valley caldera, CA, region. MInTS analysis captures the ground deformation with high spatial density over the Long Valley region.

  17. Multiscale InSAR Time Series (MInTS) analysis of surface deformation

    NASA Astrophysics Data System (ADS)

    Hetland, E. A.; Musé, P.; Simons, M.; Lin, Y. N.; Agram, P. S.; Dicaprio, C. J.

    2012-02-01

    We present a new approach to extracting spatially and temporally continuous ground deformation fields from interferometric synthetic aperture radar (InSAR) data. We focus on unwrapped interferograms from a single viewing geometry, estimating ground deformation along the line-of-sight. Our approach is based on a wavelet decomposition in space and a general parametrization in time. We refer to this approach as MInTS (Multiscale InSAR Time Series). The wavelet decomposition efficiently deals with commonly seen spatial covariances in repeat-pass InSAR measurements, since the coefficients of the wavelets are essentially spatially uncorrelated. Our time-dependent parametrization is capable of capturing both recognized and unrecognized processes, and is not arbitrarily tied to the times of the SAR acquisitions. We estimate deformation in the wavelet-domain, using a cross-validated, regularized least squares inversion. We include a model-resolution-based regularization, in order to more heavily damp the model during periods of sparse SAR acquisitions, compared to during times of dense acquisitions. To illustrate the application of MInTS, we consider a catalog of 92 ERS and Envisat interferograms, spanning 16 years, in the Long Valley caldera, CA, region. MInTS analysis captures the ground deformation with high spatial density over the Long Valley region.

  18. Characterisation Of Corner Reflectors For The Australian Geophysical Observing System To Support SAR Calibration

    NASA Astrophysics Data System (ADS)

    Thankappan, Medhavy; Garthwaite, Matthew C.; Williams, Mark L.; Hislop, Andrew; Nancarrow, Shane; Dawson, John

    2013-12-01

    The Australian Government has invested $23 million in building the Australian Geophysical Observing System (AGOS). AGOS will enable highly accurate spatial and temporal estimation of large-scale ground deformation. The key geospatial components of AGOS include Global Navigation Satellite System (GNSS) instrumentation, high precision GPS monuments, corner reflectors and a Synthetic Aperture Radar (SAR) data repository. The corner reflector (CR) array that forms a key piece of AGOS infrastructure will enable the precise measurement of crustal deformation using Interferometric SAR(InSAR) techniques. The CR array will also provide a reliable means to perform independent and ongoing radiometric, geometric and impulse response measurements for the calibration of a number of satellite-borne SAR instruments. A combination of plate sizes and materials have been used in the design and construction of 18 different CR prototypes. Radar Cross Section (RCS) measurements for all CR prototypes was undertaken at the Defence Science and Technology Organisation (DSTO) outdoor radar ground range facility to compare theoretical versus actual values for a range of azimuth and elevation combinations and characterise the design performance. The prototypes will be deployed at a field site for testing over a 3-month period. Data captures over the test site will be planned, with satellite-borne X and C-band SAR instruments to assess the response performance of the CR prototypes for calibration activities. The design, construction, RCS measurements, deployment and field performance of the CR is covered in this paper.

  19. Permanent Scatterer InSAR Analysis and Validation in the Gulf of Corinth.

    PubMed

    Elias, Panagiotis; Kontoes, Charalabos; Papoutsis, Ioannis; Kotsis, Ioannis; Marinou, Aggeliki; Paradissis, Dimitris; Sakellariou, Dimitris

    2009-01-01

    The Permanent Scatterers Interferometric SAR technique (PSInSAR) is a method that accurately estimates the near vertical terrain deformation rates, of the order of ∼1 mm year(-1), overcoming the physical and technical restrictions of classic InSAR. In this paper the method is strengthened by creating a robust processing chain, incorporating PSInSAR analysis together with algorithmic adaptations for Permanent Scatterer Candidates (PSCs) and Permanent Scatterers (PSs) selection. The processing chain, called PerSePHONE, was applied and validated in the geophysically active area of the Gulf of Corinth. The analysis indicated a clear subsidence trend in the north-eastern part of the gulf, with the maximum deformation of ∼2.5 mm year(-1) occurring in the region north of the Gulf of Alkyonides. The validity of the results was assessed against geophysical/geological and geodetic studies conducted in the area, which include continuous seismic profiling data and GPS height measurements. All these observations converge to the same deformation pattern as the one derived by the PSInSAR technique. PMID:22389587

  20. Quantifying sub-pixel urban impervious surface through fusion of optical and inSAR imagery

    USGS Publications Warehouse

    Yang, L.; Jiang, L.; Lin, H.; Liao, M.

    2009-01-01

    In this study, we explored the potential to improve urban impervious surface modeling and mapping with the synergistic use of optical and Interferometric Synthetic Aperture Radar (InSAR) imagery. We used a Classification and Regression Tree (CART)-based approach to test the feasibility and accuracy of quantifying Impervious Surface Percentage (ISP) using four spectral bands of SPOT 5 high-resolution geometric (HRG) imagery and three parameters derived from the European Remote Sensing (ERS)-2 Single Look Complex (SLC) SAR image pair. Validated by an independent ISP reference dataset derived from the 33 cm-resolution digital aerial photographs, results show that the addition of InSAR data reduced the ISP modeling error rate from 15.5% to 12.9% and increased the correlation coefficient from 0.71 to 0.77. Spatially, the improvement is especially noted in areas of vacant land and bare ground, which were incorrectly mapped as urban impervious surfaces when using the optical remote sensing data. In addition, the accuracy of ISP prediction using InSAR images alone is only marginally less than that obtained by using SPOT imagery. The finding indicates the potential of using InSAR data for frequent monitoring of urban settings located in cloud-prone areas. Copyright ?? 2009 by Bellwether Publishing, Ltd. All right reserved.

  1. An Analysis of Surface Subsidence in Chiba Using PSInSAR Technique

    NASA Astrophysics Data System (ADS)

    Li, R. H.; Zhao, Z.; Duan, M. Y.; Wang, Z. Y.; Wang, P.

    2015-06-01

    Currently, surface subsidence has become an important problem what we are facing. Because of complex topography, uneven distribution of rainfall, and the fast development of urbanization, many cities of the world have undergone surface subsidence disaster, such as Chiba, Paris, Tokyo, Beijing. The surface subsidence has occurred in Chiba since the early twenty-first century. The surface subsidence seriously threatens the safety of human life and property. In order to monitor surface subsidence, people have done a lot of research, and time-series InSAR technique with its better coverage, lower cost and high measurement accuracy advantages shows great potentiality for monitoring surface subsidence. Time-series InSAR technique can be applied for analysis of subtle surface subsidence which occurred consistently for a long term period. This paper uses time-series InSAR technique, Permanent Scatterers Interferometric SAR (PSInSAR), to monitor surface subsidence of Chiba. The used dataset consists of thirty-four Envisat ASAR images from September 2006 to August 2010. For the experimental results, this paper uses GPS data to verify the reliability of the results, and the results can provide information for local government to prevent the occurrence of surface subsidence.

  2. Canadian SAR remote sensing for the Terrestrial Wetland Global Change Research Network (TWGCRN)

    USGS Publications Warehouse

    Kaya, Shannon; Brisco, Brian; Cull, Andrew; Gallant, Alisa L.; Sadinski, Walter J.; Thompson, Dean

    2010-01-01

    The Canada Centre for Remote Sensing (CCRS) has more than 30 years of experience investigating the use of SAR remote sensing for many applications related to terrestrial water resources. Recently, CCRS scientists began contributing to the Terrestrial Wetland Global Change Research Network (TWGCRN), a bi-national research network dedicated to assessing impacts of global change on interconnected wetland-upland landscapes across a vital portion of North America. CCRS scientists are applying SAR remote sensing to characterize wetland components of these landscapes in three ways. First, they are using a comprehensive set of RADARSAT-2 SAR data collected during April to September 2009 to extract multi-temporal surface water information for key TWGCRN study landscapes in North America. Second, they are analyzing polarimetric RADARSAT-2 data to determine areas where double-bounce represents the primary scattering mechanism and is indicative of flooded vegetation in these landscapes. Third, they are testing advanced interferometric SAR techniques to estimate water levels with RADARSAT-2 Fine Quad polarimetric image pairs. The combined information from these three SAR analysis activities will provide TWGCRN scientists with an integrated view and monitoring capability for these dynamic wetland-upland landscapes. These data are being used in conjunction with other remote sensing and field data to study interactions between landscape and animal (birds and amphibians) responses to climate/global change.

  3. Resolving land subsidence within the Venice Lagoon by persistent scatterer SAR interferometry

    NASA Astrophysics Data System (ADS)

    Teatini, P.; Tosi, L.; Strozzi, T.; Carbognin, L.; Cecconi, G.; Rosselli, R.; Libardo, S.

    Land subsidence is a severe geologic hazard threatening the lowlying transitional coastal areas worldwide. Monitoring land subsidence has been significantly improved over the last decade by space borne earth observation techniques based on Synthetic Aperture Radar (SAR) interferometry. Within the INLET Project, funded by Magistrato alle Acque di Venezia - Venice Water Authority (VWA) and Consorzio Venezia Nuova (CVN), we use Interferometric Point Target Analysis (IPTA) to characterize the ground displacements within the Venice Lagoon. IPTA measures the movement of backscattering point targets (PTs) at the ground surface that persistently reflect radar signals emitted by the SAR system at different passes. For this study 80 ERS-1/2 and 44 ENVISAT SAR scenes recorded from 1992 to 2005 and from 2003 to 2007, respectively, have been processed. Highly reliable displacement measurements have been detected for thousands of PTs located on the lagoon margins, along the littorals, in major and small islands, and on single structures scattered within the lagoon. On the average, land subsidence ranges from less than 1 mm/year to 5 mm/year, with some PTs that exhibit values also larger than 10 mm/year depending on both the local geologic conditions and the anthropic activities. A network of a few tens of artificial square trihedral corner reflectors (TCRs) has been established before summer 2007 in order to monitor land subsidence in the inner lagoon areas where “natural” reflectors completely lack (e.g., on the salt marshes). The first interferometric results on the TCRs appear very promising.

  4. Remotely Sensing Tundra Fire Impacts Using InSAR

    NASA Astrophysics Data System (ADS)

    Liu, L.; Schaefer, K. M.; Jafarov, E. E.; Williams, C. A.; Rogan, J.; Zebker, H. A.

    2013-12-01

    Fire is a major disturbance affecting the arctic tundra and boreal forests, with a significant impacts on the ecosystem, soil hydrology, carbon cycling, and permafrost. The increasing trend in frequency and severity of large fires since 1980, associated with progressively drier conditions, is expected to continue and lead to still greater impacts. In this study, we explore the use of Interferometric Synthetic Aperture Radar (InSAR) to map and quantify several results of tundra fires, including fire severity, the increase in permafrost active layer thickness (ALT), and changes in organic layer thickness. Here we present as an example observations of the Anaktuvuk River fire on the North Slope of Alaska, which burned over 1,000 km2 of tundra in the summer of 2007. Fire causes an abrupt change in the surface scattering characteristics and results in a large drop in InSAR coherence. The magnitude of coherence loss is proportional to the amount of vegetation burned, and thus fire severity. Coherence between two PALSAR images taken by the Japanese ALOS satellite before and after the Anaktuvuk River fire shows a spatial pattern consistent with a map of burn severity based on optical MODIS images using differential Normalized Burn Ratio. Additionally, we used InSAR to calculate the seasonal ground subsidence for the 2006 and 2009 thaw seasons representing pre- and post-fire conditions, and estimated the change in ALT using a retrieval algorithm. Our results are consistent with the 8 to 24 cm ALT increases derived from in situ probing measurements, which we relate to the change in the organic layer thickness due to the fire. Our results illustrate the potential of InSAR for remote sensing of fire impacts in Arctic regions. (a) Burn severity for the Anaktuvuk Rivre Fire based on differential Normalized Burn Ratio (dNBR) from MODIS images. (b) Interferometric coherence loss due to the fire. Spatial mean has been subtracted. Negative values (yellow and red colors) indicate

  5. Study of Movement and Seepage Along Levees Using DINSAR and the Airborne UAVSAR Instrument

    NASA Technical Reports Server (NTRS)

    Jones, Cathleen E.; Bawden, Gerald; Deverel, Steven; Dudas, Joel; Hensley, Scott

    2012-01-01

    We have studied the utility of high resolution SAR (synthetic aperture radar) for levee monitoring using UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar) data collected along the dikes and levees in California's Sacramento-San Joaquin Delta and along the lower Mississippi River. Our study has focused on detecting and tracking changes that are indicative of potential problem spots, namely deformation of the levees, subsidence along the levee toe, and seepage through the levees, making use of polarimetric and interferometric SAR techniques. Here was present some results of those studies, which show that high resolution, low noise SAR imaging could supplement more traditional ground-based monitoring methods by providing early indicators of seepage and deformation.

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  7. Change detection in quad and dual pol, single- and bi-frequency SAR data

    NASA Astrophysics Data System (ADS)

    Nielsen, Allan A.; Conradsen, Knut; Skriver, Henning

    2015-10-01

    When the covariance matrix representation is used for multi-look polarimetric synthetic aperture radar (SAR) data, the complex Wishart distribution applies. Based on this distribution a likelihood ratio test statistic for equality of two complex variance-covariance matrices and an associated p-value are given. In a case study airborne EMISAR C- and L-band SAR images covering agricultural fields and wooded areas near Foulum, Denmark, are used in single- and bi-frequency, bi-temporal change detection with full and dual polarimetry data.

  8. Multi-spectral analysis of ice sheets using co-registered SAR and TM imagery

    NASA Technical Reports Server (NTRS)

    Vornberger, P. L.; Bindschadler, R. A.

    1992-01-01

    Landsat Thematic Mapper and airborne Synthetic Aperture Radar (SAR) imagery acquired over an area of south-western Greenland are coregistered and analyzed. Significant corrections to the SAR data were required to account for range-darkening, non-square pixel dimensions, speckle, and relief distortion. In one area, exposed rock was available for use as co-registration control, while in another area it was absent and supraglacial lakes and streams were used. The coregistered scenes highlight many differences between the optical and radar signatures of ice sheets.

  9. Bridge Collapse Revealed By Multi-Temporal SAR Interferometry

    NASA Astrophysics Data System (ADS)

    Sousa, Joaquim; Bastos, Luisa

    2013-12-01

    On the night of March 4, 2001, the Hintze Ribeiro centennial Bridge, made of steel and concrete, collapsed in Entre-os-Rios (Northern Portugal), killing 59 people, including those in a bus and three cars that were attempting to reach the other side of the Douro River. It still remains the most serious road accident in the Portuguese history. In this work we do not intend to corroborate or contradict the official version of the accident causes, but only demonstrate the potential of Multi-Temporal Interferometric (MTI-InSAR) techniques for detection and monitoring of deformations in structures such as bridges, helping to prevent new catastrophic events. Based on the analysis of 57 ERS-1/2 covering the period from December 1992 to the fatality occurrence, we were able to detect significant movements (up to 20 mm/yr) in the section of the bridge that fell in the Douro River, obvious signs of the bridge instability.

  10. Three-Dimensional Road Network by Fusion of Polarimetric and Interferometric SAR Data

    NASA Technical Reports Server (NTRS)

    Gamba, P.; Houshmand, B.

    1998-01-01

    In this paper a fuzzy classification procedure is applied to polarimetric radar measurements, and street pixels are detected. These data are successively grouped into consistent roads by means of a dynamic programming approach based on the fuzzy membership function values. Further fusion of the 2D road network extracted and 3D TOPSAR measurements provides a powerful way to analyze urban infrastructures.

  11. Coherent change detection and interferometric ISAR measurements in the folded compact range

    SciTech Connect

    Sorensen, K.W.

    1996-08-01

    A folded compact range configuration has been developed ant the Sandia National Laboratories` compact range antenna and radar-cross- section measurement facility as a means of performing indoor, environmentally-controlled, far-field simulations of synthetic aperture radar (SAR) measurements of distributed target samples (i.e. gravel, sand, etc.). The folded compact range configuration has previously been used to perform coherent-change-detection (CCD) measurements, which allow disturbances to distributed targets on the order of fractions of a wavelength to be detected. This report describes follow-on CCD measurements of other distributed target samples, and also investigates the sensitivity of the CCD measurement process to changes in the relative spatial location of the SAR sensor between observations of the target. Additionally, this report describes the theoretical and practical aspects of performing interferometric inverse-synthetic-aperture-radar (IFISAR) measurements in the folded compact range environment. IFISAR measurements provide resolution of the relative heights of targets with accuracies on the order of a wavelength. Several examples are given of digital height maps that have been generated from measurements performed at the folded compact range facility.

  12. SAR Altimetry in Coastal Zone: Performances, Limits, Perspectives

    NASA Astrophysics Data System (ADS)

    Dinardo, S.; Benveniste, J.

    2011-12-01

    Up to now, any effort to retrieve the coastal zone phenomena from the space has been hindered by the intrinsic incapacity of conventional radar altimeters to sample all but largest scales involved in the coastal processes due to its insufficient along- track resolution. However, nowadays, a new technology in Space-borne Altimetry has become reality: the Synthetic Aperture Radar (SAR) Altimeter. The acquisition of altimetric data in SAR mode ensures a higher resolving measurement power that shall enable scientists for the first time to aspire to measure even short-scale weak coastal phenomena, thanks to the 20- fold smaller along track radar resolution and 10 dB higher Signal to Noise ratio. The secondary, but significant in coastal zone, effect of the radar footprint shrinking is the expected reduced impact of land contamination on the radar waveforms in the proximity of the shore. As a consequence of this effect, the advent of SAR focusing promises to bring the satellite altimetry remote sensing closer to the shore up to around 500 meters. Anyway, this lower bound of 500 meter on coastal proximity is not always reachable, as the footprint shrinking occurs only in along track direction while the across track resolution shall remain basically unaltered. Hence, the orientation of the satellite ground-track with respect the coastline plays a role crucial for an effective filtering out of the off-nadir land-originated signals. In the present work, utilizing the current CryoSat-2 Altimeter Dataset (SAR L1b) acquired over coastal sea water, and by retracking the SAR L1b waveforms, a performances study of SAR altimetry in coastal zone will be addressed and the benefits and limits of this new technology highlighted. As particular study area, the Tyrrhenian Sea has been selected: statistics and metrics for sea surface height and significant wave height, as calculated from a cycle of passes, will be assessed, shown and interpreted. Finally, employing the Cryo

  13. InSAR Scientific Computing Environment on the Cloud

    NASA Astrophysics Data System (ADS)

    Rosen, P. A.; Shams, K. S.; Gurrola, E. M.; George, B. A.; Knight, D. S.

    2012-12-01

    In response to the needs of the international scientific and operational Earth observation communities, spaceborne Synthetic Aperture Radar (SAR) systems are being tasked to produce enormous volumes of raw data daily, with availability to scientists to increase substantially as more satellites come online and data becomes more accessible through more open data policies. The availability of these unprecedentedly dense and rich datasets has led to the development of sophisticated algorithms that can take advantage of them. In particular, interferometric time series analysis of SAR data provides insights into the changing earth and requires substantial computational power to process data across large regions and over large time periods. This poses challenges for existing infrastructure, software, and techniques required to process, store, and deliver the results to the global community of scientists. The current state-of-the-art solutions employ traditional data storage and processing applications that require download of data to the local repositories before processing. This approach is becoming untenable in light of the enormous volume of data that must be processed in an iterative and collaborative manner. We have analyzed and tested new cloud computing and virtualization approaches to address these challenges within the context of InSAR in the earth science community. Cloud computing is democratizing computational and storage capabilities for science users across the world. The NASA Jet Propulsion Laboratory has been an early adopter of this technology, successfully integrating cloud computing in a variety of production applications ranging from mission operations to downlink data processing. We have ported a new InSAR processing suite called ISCE (InSAR Scientific Computing Environment) to a scalable distributed system running in the Amazon GovCloud to demonstrate the efficacy of cloud computing for this application. We have integrated ISCE with Polyphony to

  14. Analysis of an interferometric Stokes imaging polarimeter

    NASA Astrophysics Data System (ADS)

    Murali, Sukumar

    Estimation of Stokes vector components from an interferometric fringe encoded image is a novel way of measuring the State Of Polarization (SOP) distribution across a scene. Imaging polarimeters employing interferometric techniques encode SOP in- formation across a scene in a single image in the form of intensity fringes. The lack of moving parts and use of a single image eliminates the problems of conventional polarimetry - vibration, spurious signal generation due to artifacts, beam wander, and need for registration routines. However, interferometric polarimeters are limited by narrow bandpass and short exposure time operations which decrease the Signal to Noise Ratio (SNR) defined as the ratio of the mean photon count to the standard deviation in the detected image. A simulation environment for designing an Interferometric Stokes Imaging polarimeter (ISIP) and a detector with noise effects is created and presented. Users of this environment are capable of imaging an object with defined SOP through an ISIP onto a detector producing a digitized image output. The simulation also includes bandpass imaging capabilities, control of detector noise, and object brightness levels. The Stokes images are estimated from a fringe encoded image of a scene by means of a reconstructor algorithm. A spatial domain methodology involving the idea of a unit cell and slide approach is applied to the reconstructor model developed using Mueller calculus. The validation of this methodology and effectiveness compared to a discrete approach is demonstrated with suitable examples. The pixel size required to sample the fringes and minimum unit cell size required for reconstruction are investigated using condition numbers. The importance of the PSF of fore-optics (telescope) used in imaging the object is investigated and analyzed using a point source imaging example and a Nyquist criteria is presented. Reconstruction of fringe modulated images in the presence of noise involves choosing an

  15. Interferometric observations of an artificial satellite.

    PubMed

    Preston, R A; Ergas, R; Hinteregger, H F; Knight, C A; Robertson, D S; Shapiro, I I; Whitney, A R; Rogers, A E; Clark, T A

    1972-10-27

    Very-long-baseline interferometric observations of radio signals from the TACSAT synchronous satellite, even though extending over only 7 hours, have enabled an excellent orbit to be deduced. Precision in differenced delay and delay-rate measurements reached 0.15 nanosecond ( approximately 5 centimeters in equivalent differenced distance) and 0.05 picosecond per second ( approximately 0.002 centimeter per second in equivalent differenced velocity), respectively. The results from this initial three-station experiment demonstrate the feasibility of using the method for accurate satellite tracking and for geodesy. Comparisons are made with other techniques.

  16. Light-pulse atom interferometric device

    DOEpatents

    Biedermann, Grant; McGuinness, Hayden James Evans; Rakholia, Akash; Jau, Yuan-Yu; Schwindt, Peter; Wheeler, David R.

    2016-03-22

    An atomic interferometric device useful, e.g., for measuring acceleration or rotation is provided. The device comprises at least one vapor cell containing a Raman-active chemical species, an optical system, and at least one detector. The optical system is conformed to implement a Raman pulse interferometer in which Raman transitions are stimulated in a warm vapor of the Raman-active chemical species. The detector is conformed to detect changes in the populations of different internal states of atoms that have been irradiated by the optical system.

  17. Web Service Infrastructure for Correcting InSAR Imaging

    NASA Astrophysics Data System (ADS)

    von Allmen, P. A.; Fielding, E. J.; Xing, Z.; Pan, L.; Fishbein, E.

    2011-12-01

    InSAR images can be obtained from satellite radar data by combining signals acquired at two different times along the spacecraft's orbit, at geospatial locations nearly identical. Changes in the propagation of the radar signal from the first acquisition to the second, caused for example by changes in the tropospheric water vapor content, can lead to a deterioration of the quality of the interferometric data analysis. Other extraneous effects such as ocean tidal loading can also lead to errors that reduce the potential science return of InSAR missions. Data from Global Positioning Systems and infrared radiometers are current used on an ad hoc basis for the tropospheric corrections when available, and operational weather forecast was demonstrated to be able to fill in the remaining spatial and temporal gaps. We have developed a set of web services named OSCAR (Online Services for Correcting Atmosphere in Radar) that transparently to the user retrieves remote sensing and weather forecast data and delivers atmospheric radar delays on a latitude longitude grid that can be directly integrated with Interferometric Synthetic Aperture Radar data processing software. We will describe the common web service architecture, relying on RESTful, that we developed to streamline the development of OSCAR's capabilities. We will also discuss the Bayesian averaging process that we use for merging the radiometric data with numerical weather forecast results. Correcting for biases and estimating the error model will be discussed in detail and validation results will be presented. The success of the correction procedure will be demonstrated by using MODIS data and ECMWF model output. We will also outline the extension of our online correction system to include GPS data to automatically correct for biases in the radiometric data, and a model of ocean tidal loading to correct for long wavelength errors near coastal regions.

  18. Analytical SAR-GMTI principles

    NASA Astrophysics Data System (ADS)

    Soumekh, Mehrdad; Majumder, Uttam K.; Barnes, Christopher; Sobota, David; Minardi, Michael

    2016-05-01

    This paper provides analytical principles to relate the signature of a moving target to parameters in a SAR system. Our objective is to establish analytical tools that could predict the shift and smearing of a moving target in a subaperture SAR image. Hence, a user could identify the system parameters such as the coherent processing interval for a subaperture that is suitable to localize the signature of a moving target for detection, tracking and geolocating the moving target. The paper begins by outlining two well-known SAR data collection methods to detect moving targets. One uses a scanning beam in the azimuth domain with a relatively high PRF to separate the moving targets and the stationary background (clutter); this is also known as Doppler Beam Sharpening. The other scheme uses two receivers along the track to null the clutter and, thus, provide GMTI. We also present results on implementing our SAR-GMTI analytical principles for the anticipated shift and smearing of a moving target in a simulated code. The code would provide a tool for the user to change the SAR system and moving target parameters, and predict the properties of a moving target signature in a subaperture SAR image for a scene that is composed of both stationary and moving targets. Hence, the SAR simulation and imaging code could be used to demonstrate the validity and accuracy of the above analytical principles to predict the properties of a moving target signature in a subaperture SAR image.

  19. Atypical SARS in Geriatric Patient

    PubMed Central

    Oh, Helen M.L.; Hui, K.P.; Lien, Christopher T.C.; Narendran, K.; Heng, B.H.; Ling, A.E.

    2004-01-01

    We describe an atypical presentation of severe acute respiratory syndrome (SARS) in a geriatric patient with multiple coexisting conditions. Interpretation of radiographic changes was confounded by cardiac failure, with resolution of fever causing delayed diagnosis and a cluster of cases. SARS should be considered even if a contact history is unavailable, during an ongoing outbreak. PMID:15030694

  20. Sentinel-1 DInSAR processing chain within Geohazard Exploitation Platform

    NASA Astrophysics Data System (ADS)

    Zinno, Ivana; Bonano, Manuela; Buonanno, Sabatino; Casu, Francesco; De Luca, Claudio; Fusco, Adele; Lanari, Riccardo; Manunta, Michele; Manzo, Mariarosaria; Ojha, Chandrakanta; Pepe, Antonio

    2016-04-01

    The Sentinel-1A (S1A) satellite has been launched on April 2014 to acquire SAR data in continuity with the ERS-1/2 and ENVISAT missions. It presents advanced characteristics in terms of revisit time, spatial coverage and service reliability. Such a satellite will be paired during 2016 with the Sentinel-1B twin system that will reduce the constellation revisit time from 12 to 6 days. Accordingly, a huge and ever-increasing data flow relevant to extended areas on Earth will be delivered with a "free and open access" data policy. The S1-A sensor is equipped with a C-band SAR instrument that is conceived for interferometric applications, thus allowing us to analyze Earth's surface displacements through the Differential SAR Interferometry (DInSAR) technique. In particular, S1A SAR data are collected through the Terrain Observation by Progressive Scans (TOPS) mode, which generates Interferometric Wide Swath (IWS) acquisitions. To properly handle S1A TOPS data, the existing DInSAR processing chains have to be adapted with new procedures, which properly take into account the characteristics of this new acquisition mode. Furthermore, another critical point to be taken into account in designing a S1A DInSAR processing chain is the achievement of a good computational efficiency. Indeed, the capability to process in reduced time frames the huge data stream expected by S1A (and, very soon, also by S1B) is a key aspect to fully exploit S1 data archives. In this work we present an efficient interferometric processing chain, based on the advanced DInSAR algorithm referred to as Parallel Small BAseline Subset (P-SBAS), for the generation of S1A IWS surface deformation time-series. It ingests the Single Look Complex data and generates, in unsupervised way, interferograms and displacement time-series. This processing chain is able to exploit distributed computing architectures taking advantage of both multi-node and multi-threading programming techniques. The proposed S1A P

  1. Advanced InSAR imaging for dune mapping

    NASA Astrophysics Data System (ADS)

    Havivi, Shiran; August, Yitzhak; Blumberg, Dan G.; Rotman, Stanley R.

    2015-04-01

    Aeolian morphologies are formed in the presence of sufficient wind energy and available particles. These processes occur naturally or are further enhanced or reduced by human intervention. The dimensions of change are dependent primarily on the wind energy and surface properties. Since the 1970's, remote sensing imagery both optical and radar, are used for documentation and interpretation of the geomorphologic changes of sand dunes. Remote sensing studies of Aeolian morphologies is mostly useful to document major changes, yet, subtle changes, occurring in a period of days or months in scales of centimeters, are very difficult to detect in imagery. Interferometric Synthetic Aperture Radar (InSAR) is an imaging technique for measuring Earth's surface topography and deformation. InSAR images are produced by measuring the radar phase difference between two separated antennas that view the same surface area. Classical InSAR is based on high coherence between two images or more. The output (interferogram) can show subtle changes with an accuracy of several millimeters to centimeters. Very little work has been done on measuring or identifying the changes in dunes using InSAR. The reason is that dunes tend to be less coherent than firm, stable, surfaces. This research aims to demonstrate how interferometric decorrelation, or, coherence change detection, can be used for identifying dune instability. We hypothesize and demonstrate that the loss of radar coherence over time on dunes can be used as an indication of the dune's instability. When SAR images are acquired at sufficiently close intervals one can measure the time it takes to lose coherence and associate this time with geomorphic stability. To achieve our goals, the Nitzanim coastal dunes along the Mediterranean, 40 km south of Tel-Aviv, Israel, were chosen as a case study. The dunes in this area are of varying levels of stability and vegetation cover and have been monitored meteorologically, geomorphologically and

  2. Two-target height effects on interferometric synthetic aperture radar coherence

    NASA Astrophysics Data System (ADS)

    Yocky, David A.; Jakowatz, Charles V., Jr.

    2000-08-01

    Useful products generated from interferometric synthetic aperture radar (IFSAR) complex data include height measurement, coherent change detection, and classification. The IFSAR coherence is a spatial measure of complex correlation between two collects, a product of IFSAR signal processing. A tacit assumption in such IFSAR signal processing is that the terrain height is constant across an averaging box used in the process of correlating the two images. This paper presents simulations of IFSAR coherence if two target with different heights exist in a given correlation cell, a condition in IFSAR collections produced by layover. It also includes airborne IFSAR data confirming the simulation results. The paper concludes by exploring the implications of the results on IFSAR height measurements and classification.

  3. Studies of Aleutian volcanoes based on two decades of SAR imagery

    NASA Astrophysics Data System (ADS)

    Lu, Z.; Dzurisin, D.

    2015-12-01

    With its global coverage and all-weather imaging capability, interferometric synthetic aperture radar (InSAR) has become an increasingly important technique for studying magma dynamics at volcanoes in remote regions, such as the Aleutian Islands. The spatial distribution of surface deformation derived from InSAR data enables the construction of detailed mechanical models to aid the investigation of magmatic processes. We processed nearly 12,000 SAR images of Aleutian volcanoes acquired by ERS-1, JERS-1, ERS-2, Radarsat-1, Envisat, ALOS, and TerraSAR-X from the early 1990s to 2010. We combined these SAR images to produce about 25,000 interferograms, which we analyzed for evidence of surface deformation at most of the arc's Holocene volcanoes. This talk summarizes deformation processes at Aleutian volcanoes observed with InSAR, including: (1) time-varying volcanic inflation and magmatic intrusion, (2) deformation preceding and accompanying seismic swarms , (3) persistent volcano-wide subsidence at calderas that last erupted tens of years ago, (4) episodic magma intrusion and associated tectonic stress release, (5) subsidence caused by a decrease in pore fluid pressure in active hydrothermal systems, (6) subsidence of surface lava and pyroclastic flows, and (7) a lack of deformation at some volcanoes with recent eruptions, where deformation might be expected. Our work demonstrates that deformation patterns and associated magma supply mechanisms at Aleutian volcanoes are diverse and vary in both space and time. By combining InSAR results with information from the geologic record, accounts of historical eruptions, and data from seismology, petrology, gas geochemistry, and other sources, we have developed conceptual models for the magma plumbing systems and behaviors of many volcanoes in the Aleutian arc. We realize that these models are simplistic, but it is our hope that they will serve as foundations that will be refined as additional information becomes available.

  4. Investigations with the Sentinel-1 Interferometric Wide Swath mode: first results and comparison with in-situ geodetic data

    NASA Astrophysics Data System (ADS)

    Borgstrom, Sven; Del Gaudio, Carlo; De Martino, Prospero; Ricciardi, Giovanni P.; Ricco, Ciro; Siniscalchi, Valeria; Prats-Iraola, Pau; Nannini, Matteo; Costantini, Mario; Minati, Federico; Walter, Thomas

    2015-04-01

    The contribution focuses on the current status of the ESA study entitled "INSARAP: Sentinel-1 InSAR Performance study with TOPS Data". The study investigates the performance of the interferometric wide swath (IW) mode of Sentinel-1, which is implemented using the terrain observation by progressive scans (TOPS) mode. In this regard, first analyses with Sentinel-1 time series will be shown, with a comparison with in-situ geodetic measurements on different test sites identified in the framework of the study, namely, Campi Flegrei/Vesuvius area in Italy, Istanbul city in Turkey, and Mexico City. The evaluation of the results will be performed by exploiting mainly continuous GPS stations located on the different sites, besides leveling measurements when also available. Also in a recent past, the comparison between InSAR and continuous GPS data, the latter projected into the radar LOS, has proven to be very effective for a cross comparison, besides InSAR Cal/Val activities, as it was for instance in the case of the recent inflation events occurred in Campi Flegrei area, marked by the well know bradyseismic phenomenon. Although continuous GPS networks are characterized by a poor space coverage in comparison with InSAR results, continuous GPS data recording allows to complement the geodetic information from InSAR sensors, limited by their revisiting time. The issue to be faced in this study is the possibility to deal with very low deformation rates in comparison with the Sentinel-1 C-band data, although the Sentinel-1 time series we expect to get from October 2014 to date should allow the identification of ground deformation in the areas of interest.

  5. Review of bats and SARS.

    PubMed

    Wang, Lin-Fa; Shi, Zhengli; Zhang, Shuyi; Field, Hume; Daszak, Peter; Eaton, Bryan T

    2006-12-01

    Bats have been identified as a natural reservoir for an increasing number of emerging zoonotic viruses, including henipaviruses and variants of rabies viruses. Recently, we and another group independently identified several horseshoe bat species (genus Rhinolophus) as the reservoir host for a large number of viruses that have a close genetic relationship with the coronavirus associated with severe acute respiratory syndrome (SARS). Our current research focused on the identification of the reservoir species for the progenitor virus of the SARS coronaviruses responsible for outbreaks during 2002-2003 and 2003-2004. In addition to SARS-like coronaviruses, many other novel bat coronaviruses, which belong to groups 1 and 2 of the 3 existing coronavirus groups, have been detected by PCR. The discovery of bat SARS-like coronaviruses and the great genetic diversity of coronaviruses in bats have shed new light on the origin and transmission of SARS coronaviruses.

  6. Review of Bats and SARS

    PubMed Central

    Shi, Zhengli; Zhang, Shuyi; Field, Hume; Daszak, Peter; Eaton, Bryan T.

    2006-01-01

    Bats have been identified as a natural reservoir for an increasing number of emerging zoonotic viruses, including henipaviruses and variants of rabies viruses. Recently, we and another group independently identified several horseshoe bat species (genus Rhinolophus) as the reservoir host for a large number of viruses that have a close genetic relationship with the coronavirus associated with severe acute respiratory syndrome (SARS). Our current research focused on the identification of the reservoir species for the progenitor virus of the SARS coronaviruses responsible for outbreaks during 2002–2003 and 2003–2004. In addition to SARS-like coronaviruses, many other novel bat coronaviruses, which belong to groups 1 and 2 of the 3 existing coronavirus groups, have been detected by PCR. The discovery of bat SARS-like coronaviruses and the great genetic diversity of coronaviruses in bats have shed new light on the origin and transmission of SARS coronaviruses. PMID:17326933

  7. Bistatic SAR: Imagery & Image Products.

    SciTech Connect

    Yocky, David A.; Wahl, Daniel E.; Jakowatz, Charles V,

    2014-10-01

    While typical SAR imaging employs a co-located (monostatic) RADAR transmitter and receiver, bistatic SAR imaging separates the transmitter and receiver locations. The transmitter and receiver geometry determines if the scattered signal is back scatter, forward scatter, or side scatter. The monostatic SAR image is backscatter. Therefore, depending on the transmitter/receiver collection geometry, the captured imagery may be quite different that that sensed at the monostatic SAR. This document presents imagery and image products formed from captured signals during the validation stage of the bistatic SAR research. Image quality and image characteristics are discussed first. Then image products such as two-color multi-view (2CMV) and coherent change detection (CCD) are presented.

  8. Seasonal effects on the estimation of height of boreal and deciduous forests from interferometric TanDEM-X coherence data

    NASA Astrophysics Data System (ADS)

    Olesk, Aire; Voormansik, Kaupo; Tamm, Tanel; Noorma, Mart; Praks, Jaan

    2015-10-01

    The aim of this study is to assess the performance of single-pass X-band bistatic SAR interferometric forest height estimation of boreal and temperate deciduous forests under variable seasonal conditions. For this, twelve acquisitions of single- and dual-polarized TanDEM-X coherence images over 118 forest stands were analyzed and compared against LiDAR forest height maps. Strong correlations were found between interferometric coherence magnitude and LiDAR derived forest stand height for pine forests (r2=0.94) and spruce forest (r2=0.87) as well as for deciduous trees (r2=0.94) during leaf-off conditions with temperatures below 0°C. It was found that coherence magnitude based forest height estimation is influenced by leaf-on and leaf-off conditions as well as daily temperature fluctuations, height of ambiguity and effective baseline. These factors alter the correlation and should be taken into account for accurate coherence-based height retrieval. Despite the influence of the mentioned factors, generally a strong relationship in regression analysis between X-band SAR coherence and LiDAR derived forest stand height can be found. Moreover, a simple semi empirical model, derived from Random Volume over Ground model, is presented. The model takes into account all imaging geometry dependent parameters and allows to derive tree height estimate without a priori knowledge. Our results show that X-band SAR interferometry can be used to estimate forest canopy height for boreal and deciduous forests in both summer and winter, but the conditions should be stable.

  9. Comparison of High Resolution Topographic Data Sources (SAR, IfSAR, and LiDAR) for Storm Surge Hazard Maps

    NASA Astrophysics Data System (ADS)

    Suarez, J. K. B.; Santiago, J. T.; Muldong, T. M. M.; Lagmay, A. M. A.; Caro, C. V.; Ramos, M.

    2014-12-01

    As an archipelagic country, the Philippines has experienced multiple storm surge threats. Moreover, the country's location, adjacent to the Pacific Ocean, results in an average of eight to nine typhoons that make landfall in a year. Storm surge hazard maps require high resolution topographic data to illustrate water inflow in the event of storm surges in vulnerable coastal areas and for accurate boundaries and coastline. Furthermore, potential hazard areas tend to be generalized in lower resolution data. The objective of this research is to compare three sources where accurate and quality storm surge hazard maps will draw bases from. For this purpose, the researcher used and compared SAR, IfSAR and LiDAR. The study involved comparing maps from different topographic data sources in Tacloban, in the province of Leyte. This area was one of the most heavily stricken areas during typhoon Haiyan where more than 6,000 people died and P34.37 billion worth of property was destroyed. In the comparison of the three sources, the following had be taken into consideration: cost of acquiring data, processing time, purpose, and the results. The research learned the following: Synthetic Aperture Radar or SAR produces data with a 30 meter resolution, while Interferometric Synthetic Aperture Radar (IfSAR) offers a resolution of 5 meters. Light Detection and Ranging (LiDAR) has the highest resolution of the three with 1 meter. In addition, higher costs are paid for more detailed topographic data. Also, processing time takes longer for finer details due to the memory of the computer units used for modelling. The sources were also evaluated on the necessity of the scale at which the maps are needed for specific purposes such as practicality and direct disaster response. Results from the maps have been validated through interviews with the locals on the experience of actual storm surges. Through this study, the researcher concluded that although LiDAR can offer a more detailed and

  10. Growth of a young pingo in the Canadian Arctic observed by RADARSAT-2 interferometric satellite radar

    NASA Astrophysics Data System (ADS)

    Samsonov, Sergey V.; Lantz, Trevor C.; Kokelj, Steven V.; Zhang, Yu

    2016-04-01

    Advancements in radar technology are increasing our ability to detect Earth surface deformation in permafrost environments. In this paper we use satellite Differential Interferometric Synthetic Aperture Radar (DInSAR) to describe the growth of a large, relatively young pingo in the Tuktoyaktuk Coastlands. High-resolution RADARSAT-2 imagery (2011-2014) analyzed with the Multidimensional Small Baseline Subset (MSBAS) DInSAR revealed a maximum 2.7 cm yr-1 of domed uplift located in a drained lake basin. Satellite measurements suggest that this feature is one of the largest diameter pingos in the region that is presently growing. Observed changes in elevation were modeled as a 348 × 290 m uniformly loaded elliptical plate with clamped edge. Analysis of historical aerial photographs suggested that ground uplift at this location initiated sometime between 1935 and 1951 following drainage of the residual pond. Uplift is largely due to the growth of intrusive ice, because the 9 % expansion of pore water associated with permafrost aggradation into saturated sands is not sufficient to explain the observed short- and long-term deformation rates. The modeled thickness of ice-rich permafrost using the Northern Ecosystem Soil Temperature (NEST) was consistent with the maximum height of this feature. Modeled permafrost aggradation from 1972 to 2014 approximated elevation changes estimated from aerial photographs for that time period. Taken together, these lines of evidence indicate that uplift is at least in part a result of freezing of the sub-pingo water lens. Seasonal variations in the uplift rate seen in the DInSAR data closely match the modeled seasonal pattern in the deepening rate of freezing front. This study demonstrates that interferometric satellite radar can detect and contribute to understanding the dynamics of terrain uplift in response to permafrost aggradation and ground ice development in remote polar environments. The present-day growth rate is smaller than

  11. Application of small baseline subsets D-InSAR technique to estimate time series land deformation of Jinan area, China

    NASA Astrophysics Data System (ADS)

    Liu, Xiangtong; Cao, Qiuxiang; Xiong, Zhuguo; Yin, Haitao; Xiao, Genru

    2016-04-01

    Jinan, located in the South of the North China Plain, is an area where underground water has been exploited excessively. However, land deformation surveys only focus on the small district obtained by GPS and Leveling. Here, we use interferometric synthetic aperture radar (InSAR) time-series of ASAR data to resolve land subsidence in the entire Jinan region. In our research, we get 20 interferograms with a temporal threshold of 700 days and spatial-baseline threshold of 300 m from 14 ASAR satellite images on a descending orbit, and then get the surface displacement using Small Baseline InSAR (SBAS D-InSAR) retrained with a periodic model. Meanwhile, the accuracy of our work is proved by the results of GPS measurements. Finally, several settlement funnels are observed with extreme values of -20 cm, and their generation is related to massive groundwater extraction.

  12. Application of small baseline subsets D-InSAR technique to estimate time series land deformation of Jinan area, China

    NASA Astrophysics Data System (ADS)

    Liu, Xiangtong; Cao, Qiuxiang; Xiong, Zhuguo; Yin, Haitao; Xiao, Genru

    2016-04-01

    Jinan, located in the South of the North China Plain, is an area where underground water has been exploited excessively. However, land deformation surveys only focus on the small district obtained by GPS and Leveling. Here, we use interferometric synthetic aperture radar (InSAR) time-series of ASAR data to resolve land subsidence in the entire Jinan region. In our research, we get 20 interferograms with a temporal threshold of 700 days and spatial-baseline threshold of 300 m from 14 ASAR satellite images on a descending orbit, and then get the surface displacement using Small Baseline InSAR (SBAS D-InSAR) retrained with a periodic model. Meanwhile, the accuracy of our work is proved by the results of GPS measurements. Finally, several settlement funnels are observed with extreme values of -20 cm, and their generation is related to massive groundwater extraction.

  13. Corner Reflectors as the Tie Between InSAR and GNSS Measurements: Case Study of Resource Extraction in Australia

    NASA Astrophysics Data System (ADS)

    Garthwaite, Matthew C.; Lawrie, Sarah; Dawson, John; Thankappan, Medhavy

    2015-05-01

    The combination of continuous Global Navigation Satellite System (GNSS) measurements over a sparse network of points covering Australia with relatively low frequency but high spatial density observations from Interferometric Synthetic Aperture Radar (InSAR) is fundamental to the new geodetic reference frame being developed for Australia. Recognising the economic importance of improved positional accuracy and the potential for geodetic tools to contribute to an understanding of energy related issues, the Australian Government has funded an innovative regional geodetic network of GNSS survey marks and co-located radar corner reflectors. This new network has been installed in the Surat Basin, Queensland where regional subsidence is expected due to significant resource extraction from the subsurface. In this contribution we present initial observations of the a-priori line-of-sight height error derived from corner reflector response in TerraSAR-X, Sentinel-1A, RADARSAT-2 and ALOS-2 SAR imagery of the Surat Basin.

  14. Invited review article: Interferometric gravity wave detectors.

    PubMed

    Cella, G; Giazotto, A

    2011-10-01

    A direct detection of gravitational waves is still lacking today. A network of several earthbound interferometric detectors is currently operating with a continuously improving sensitivity. The window of interest for observation has a lower cut off in the frequency domain below some tens of hertz, determined by the effect of seismic motion. For larger frequencies, the sensitivity is limited by thermal effects below few hundreds of hertz and by the quantum nature of light above that value. Each of these sources of noise pose a big technological challenge to experimentalists, and there are big expectations for the next generation of detectors. A reduction of thermal effects by at least one order of magnitude will be obtained with new and carefully designed materials. At that point the quantum nature of light will become an issue, and the use of quantum non-demolition techniques will become mandatory. In this review, we discuss interferometric detection of gravitational waves from an instrumental point of view. We try to address conceptually important issues with an audience of non-experts in mind. A particular emphasis is given to the description of the current limitations and to the perspectives of beating them. PMID:22047273

  15. Invited review article: Interferometric gravity wave detectors.

    PubMed

    Cella, G; Giazotto, A

    2011-10-01

    A direct detection of gravitational waves is still lacking today. A network of several earthbound interferometric detectors is currently operating with a continuously improving sensitivity. The window of interest for observation has a lower cut off in the frequency domain below some tens of hertz, determined by the effect of seismic motion. For larger frequencies, the sensitivity is limited by thermal effects below few hundreds of hertz and by the quantum nature of light above that value. Each of these sources of noise pose a big technological challenge to experimentalists, and there are big expectations for the next generation of detectors. A reduction of thermal effects by at least one order of magnitude will be obtained with new and carefully designed materials. At that point the quantum nature of light will become an issue, and the use of quantum non-demolition techniques will become mandatory. In this review, we discuss interferometric detection of gravitational waves from an instrumental point of view. We try to address conceptually important issues with an audience of non-experts in mind. A particular emphasis is given to the description of the current limitations and to the perspectives of beating them.

  16. Anatomy of a SAR impulse response.

    SciTech Connect

    Doerry, Armin Walter

    2007-08-01

    A principal measure of Synthetic Aperture Radar (SAR) image quality is the manifestation in the SAR image of a spatial impulse, that is, the SAR's Impulse Response (IPR). IPR requirements direct certain design decisions in a SAR. Anomalies in the IPR can point to specific anomalous behavior in the radar's hardware and/or software.

  17. Soviet oceanographic synthetic aperture radar (SAR) research

    SciTech Connect

    Held, D.N.; Gasparovic, R.F.; Mansfield, A.W.; Melville, W.K.; Mollo-Christensen, E.L.; Zebker, H.A.

    1991-01-01

    Radar non-acoustic anti-submarine warfare (NAASW) became the subject of considerable scientific investigation and controversy in the West subsequent to the discovery by the Seasat satellite in 1978 that manifestations of underwater topography, thought to be hidden from the radar, were visible in synthetic aperture radar (SAR) images of the ocean. In addition, the Seasat radar produced images of ship wakes where the observed angle between the wake arms was much smaller than expected from classical Kelvin wake theory. These observations cast doubt on the radar oceanography community's ability to adequately explain these phenomena, and by extension on the ability of existing hydrodynamic and radar scattering models to accurately predict the observability of submarine-induced signatures. If one is of the opinion that radar NAASW is indeed a potentially significant tool in detecting submerged operational submarines, then the Soviet capability, as evidenced throughout this report, will be somewhat daunting. It will be shown that the Soviets have extremely fine capabilities in both theoretical and experimental hydrodynamics, that Soviet researchers have been conducting at-sea radar remote sensing experiments on a scale comparable to those of the United States for several years longer than we have, and that they have both an airborne and spaceborne SAR capability. The only discipline that the Soviet Union appears to be lacking is in the area of digital radar signal processing. If one is of the opinion that radar NAASW can have at most a minimal impact on the detection of submerged submarines, then the Soviet effort is of little consequence and poses not threat. 280 refs., 31 figs., 12 tabs.

  18. Studies of ice sheet hydrology using SAR

    NASA Technical Reports Server (NTRS)

    Bindschadler, R. A.; Vornberger, P. L.

    1989-01-01

    Analysis of SAR data of the Greenland ice sheet in summer and winter suggest the use of SAR to monitor the temporal hydrology of ice sheets. Comparisons of each SAR data set with summer Landsat TM imagery show an areal-positive correlation with summer SAR data and a negative correlation with winter SAR data. It is proposed that the summer SAR data are most sensitive to the variable concentrations of free water in the surface snow and that the winter SAR data indicate variations in snow grain size.

  19. ERS-1 SAR data processing

    NASA Technical Reports Server (NTRS)

    Leung, K.; Bicknell, T.; Vines, K.

    1986-01-01

    To take full advantage of the synthetic aperature radar (SAR) to be flown on board the European Space Agency's Remote Sensing Satellite (ERS-1) (1989) and the Canadian Radarsat (1990), the implementation of a receiving station in Alaska is being studied to gather and process SAR data pertaining in particular to regions within the station's range of reception. The current SAR data processing requirement is estimated to be on the order of 5 minutes per day. The Interim Digital Sar Processor (IDP) which was under continual development through Seasat (1978) and SIR-B (1984) can process slightly more than 2 minutes of ERS-1 data per day. On the other hand, the Advanced Digital SAR Processore (ADSP), currently under development for the Shuttle Imaging Radar C (SIR-C, 1988) and the Venus Radar Mapper, (VMR, 1988), is capable of processing ERS-1 SAR data at a real time rate. To better suit the anticipated ERS-1 SAR data processing requirement, both a modified IDP and an ADSP derivative are being examined. For the modified IDP, a pipelined architecture is proposed for the mini-computer plus array processor arrangement to improve throughout. For the ADSP derivative, a simplified version is proposed to enhance ease of implementation and maintainability while maintaing real time throughput rates. These processing systems are discussed and evaluated.

  20. Source mechanism analysis of strong mining induced seismic event and its influence on ground deformation observed by InSAR technique.

    NASA Astrophysics Data System (ADS)

    Rudzinski, Lukasz; Mirek, Katarzyna; Mirek, Janusz

    2016-04-01

    On April 17th, 2015 a strong shallow seismic event M4.0 struck a mining panel in the Wujek-Slask coal mine, southern Poland. The event was widely felt, followed with rockburst and caused a strong damages inside mining corridors. Unfortunately two miners are trapped by tunnels collapse. Full Moment Tensor (MT) estimated with regional broad-band signals shows that the event was characterized with very high isotropic (implosive) part. Mining inspections verified the occurrence of a rockfall and floor uplift. Very shallow foci depth (less than 1000m) and collapse - like MT solution suggest that event could be responsible for surface deformation in the vicinity of epicenter. To verified this issue we used the Interferometric Synthetic Aperture Radar technique (InSAR). The InSAR relies on measuring phase differences between two SAR images (radarograms). The measured differences may be computed into a single interferometric image. i.e. an interferogram. Interferogram computed from two radarograms of the same terrain taken at different time allows detecting changes in elevation of the terrain. Two SAR scenes acquired by Sentinel-1 satellite (European Space Agency) were processed to obtain the interferogram covered study area (12.04.2015 and 24.04.2015). 12 days interval differential interferogram shows distinctive concentric feature which indicate subsidence trough. Subsidence pattern shows 1 cycle of deformation corresponding with about 2.5 cm subsidence. The InSAR solution support the reliability of very strong implosive MT part.

  1. SAR Image Coregistration Based on Topography and Deformation

    NASA Astrophysics Data System (ADS)

    Yun, S.; Kim, S.; Rosen, P.

    2008-12-01

    L-band repeat-pass InSAR has been getting scientists' attention for its penetration depth through dense vegetation, revealing the ground deformation under the canopy of forest. This makes it possible to achieve a good coverage of volcanic activities in tropical areas such as Hawaii, Galapagos, and Indonesia. Another advantage of L-band InSAR is its tolerance to a large baseline. The critical baseline scales with the wavelength, and practically a baseline of over 1 km often produces interferograms. However, the large baseline causes parallax in the presence of topography, which appears as pixel shift between master and slave images that sometimes leads to a severe decorrelation. Using ALOS PALSAR data of Java Island, Indonesia, and intermediate files produced by ROI_PAC, we correct this parallax before forming an interferogram to improve the interferometric coherence. We also test an automatic implementation of the 'rubber sheeting" coregistration (e.g. Yun et al., GRL, 2007) for localized large deformation that cannot be explained by polynomial fitting.

  2. Remote identification of potential polar bear maternal denning habitat in northern Alaska using airborne LiDAR

    NASA Astrophysics Data System (ADS)

    Jones, B. M.; Durner, G. M.; Stoker, J.; Shideler, R.; Perham, C.; Liston, G. E.

    2013-12-01

    Polar bear (Ursus maritimus) populations throughout the Arctic are being threatened by reductions in critical sea ice habitat. Throughout much of their range, polar bears give birth to their young in winter dens that are excavated in snowdrifts. New-born cubs, which are unable to survive exposure to Arctic winter weather, require 2-3 months of the relatively warm, stable, and undisturbed environment of the den for their growth. In the southern Beaufort Sea (BS), polar bears may den on the Alaskan Arctic Coastal Plain (ACP).The proportion of dens occurring on land has increased because of reductions in stable multi-year ice, increases in unconsolidated ice, and lengthening of the fall open-water period. Large portions of the ACP are currently being used for oil and gas activities and proposed projects will likely expand this footprint in the near future. Since petroleum exploration and development activities increase during winter there is the potential for human activities to disturb polar bears in maternal dens. Thus, maps showing the potential distribution of terrestrial denning habitat can help to mitigate negative interactions. Prior remote sensing efforts have consisted of manual interpretation of vertical aerial photography and automated classification of Interferometric Synthetic Aperture (IfSAR) derived digital terrain models (DTM) (5-m spatial resolution) focused on the identification of snowdrift forming landscape features. In this study, we assess the feasibility of airborne Light Detection and Ranging (LiDAR) data (2-m spatial resolution) for the automated classification of potential polar bear maternal denning habitat in a 1,400 km2 area on the central portion of the ACP. The study region spans the BS coast from the Prudhoe Bay oilfield in the west to near Point Thompson in the east and extends inland from 10 to 30 km. Approximately 800 km2 of the study area contains 19 known den locations, 51 field survey sites with information on bank height and

  3. Contribution of SAR interferometry (InSAR) to the study of alpine glaciers. The example of Forni Glacier (Central Alps, Italy): preliminary results

    NASA Astrophysics Data System (ADS)

    Sterzai, P.; Mancini, F.; Corazzato, C.; D Agata, C.; Diolaiuti, G.

    2003-04-01

    Aiming at reconstructing superficial velocity and volumetric variations of alpine glaciers, SAR interferometry (InSAR) technique is, for the first time in Italy, applied jointly with the glaciological classic field methods. This methodology with its quantitative results provides, together with other space geodesy techniques like GPS, some fundamental elements for the estimation of the climate forcing and the evaluation of the future glacier trend. InSAR is usually applied to antarctic glaciers and to other wide extralpine glaciers, detectable by the SAR orbits; in the Italian Alps, the limited surface area of the glaciers and the deformation of radar images due to strong relief effect, reduce the applicability of this tecnique. The chosen glacier is suitable for this kind of study both for its large size and for the many field data collected and available for the interferometric results validation. Forni Glacier is the largest valley glacier in the Italian Alps and represents a good example of long term monitoring of a valley glacier in the Central Alps. It is a north facing valley glacier formed by 3 ice streams, located in Italian Lombardy Alps (46 23 50 N, 10 35 00 E). In 2002 its area was approximately 13 km2, extending from 2500 to 3684 m a.s.l., with a maximum width of approximately 7500 m and a maximum length of about 5000 m. Available data include mass-balance measurements on the glacier tongue (from the hydrological year 1992-1993 up to now), frontal variations data from 1925 up to now, topographical profiling by means of GPS techniques and profiles of the glacier bed by geoelectrical surveys (VES) (Guglielmin et alii, 1995) and by seismic surveys (Merlanti et alii, 2001). In order to apply radar interferometry on this glacier eight ERS SAR RAW images have been purchased, in addition to the Digital Elevation Model from IGM (Geographic Military Institute), and repeat pass interferometry used. Combining the different passes, differential interferograms are

  4. InSAR detects increase in surface subsidence caused by an Arctic tundra fire

    NASA Astrophysics Data System (ADS)

    Liu, Lin; Jafarov, Elchin E.; Schaefer, Kevin M.; Jones, Benjamin M.; Zebker, Howard A.; Williams, Christopher A.; Rogan, John; Zhang, Tingjun

    2014-06-01

    Wildfire is a major disturbance in the Arctic tundra and boreal forests, having a significant impact on soil hydrology, carbon cycling, and permafrost dynamics. This study explores the use of the microwave Interferometric Synthetic Aperture Radar (InSAR) technique to map and quantify ground surface subsidence caused by the Anaktuvuk River fire on the North Slope of Alaska. We detected an increase of up to 8 cm of thaw-season ground subsidence after the fire, which is due to a combination of thickened active layer and permafrost thaw subsidence. Our results illustrate the effectiveness and potential of using InSAR to quantify fire impacts on the Arctic tundra, especially in regions underlain by ice-rich permafrost. Our study also suggests that surface subsidence is a more comprehensive indicator of fire impacts on ice-rich permafrost terrain than changes in active layer thickness alone.

  5. Sparse multipass 3D SAR imaging: applications to the GOTCHA data set

    NASA Astrophysics Data System (ADS)

    Austin, Christian D.; Ertin, Emre; Moses, Randolph L.

    2009-05-01

    Typically in SAR imaging, there is insufficient data to form well-resolved three-dimensional (3D) images using traditional Fourier image reconstruction; furthermore, scattering centers do not persist over wide-angles. In this work, we examine 3D non-coherent wide-angle imaging on the GOTCHA Air Force Research Laboratory (AFRL) data set; this data set consists of multipass complete circular aperture radar data from a scene at AFRL, with each pass varying in elevation as a result of aircraft flight dynamics . We compare two algorithms capable of forming well-resolved 3D images over this data set: regularized lp least-squares inversion, and non-uniform multipass interferometric SAR (IFSAR).

  6. InSAR detects increase in surface subsidence caused by an Arctic tundra fire

    USGS Publications Warehouse

    Liu, Lin; Jafarov, Elchin E.; Schaefer, Kevin M.; Jones, Benjamin M.; Zebker, Howard A.; Williams, Christopher A.; Rogan, John; Zhang, Tingjun

    2014-01-01

    Wildfire is a major disturbance in the Arctic tundra and boreal forests, having a significant impact on soil hydrology, carbon cycling, and permafrost dynamics. This study explores the use of the microwave Interferometric Synthetic Aperture Radar (InSAR) technique to map and quantify ground surface subsidence caused by the Anaktuvuk River fire on the North Slope of Alaska. We detected an increase of up to 8 cm of thaw-season ground subsidence after the fire, which is due to a combination of thickened active layer and permafrost thaw subsidence. Our results illustrate the effectiveness and potential of using InSAR to quantify fire impacts on the Arctic tundra, especially in regions underlain by ice-rich permafrost. Our study also suggests that surface subsidence is a more comprehensive indicator of fire impacts on ice-rich permafrost terrain than changes in active layer thickness alone.

  7. DEM generation and tidal deformation detection for sulzberger ice shelf, West Antarctica using SAR interferometry

    USGS Publications Warehouse

    Baek, S.; Kwoun, Oh-Ig; Bassler, M.; Lu, Zhiming; Shum, C.K.; Dietrich, R.

    2004-01-01

    In this study we generated a relative Digital Elevation Model (DEM) over the Sulzberger Ice Shelf, West Antarctica using ERS1/2 synthetic aperture radar (SAR) interferometry data. Four repeat pass differential interferograms are used to find the grounding zone and to classify the study area. An interferometrically derived DEM is compared with laser altimetry profile from ICESat. Standard deviation of the relative height difference is 5.12 m and 1.34 m in total length of the profile and at the center of the profile respectively. The magnitude and the direction of tidal changes estimated from interferogram are compared with those predicted tidal differences from four ocean tide models. Tidal deformation measured in InSAR is -16.7 cm and it agrees well within 3 cm with predicted ones from tide models.

  8. Research on interferometric photonic crystal fiber hydrophone

    NASA Astrophysics Data System (ADS)

    Luo, Hong; Zhang, Zhen-hui; Wang, Fu-yin; Xiong, Shui-dong

    2013-08-01

    Current research on photonic crystal fiber (PCF) for acoustic sensing was focused on the PCF's pressure sensitivity enhancement. However, whether the enhancement of the PCF's pressure sensitivity can be actually realized is still controversial. Practical hydrophone, utilizing PCFs, to manifest its superior sensitivity to normal single mode fibers (SMFs) for acoustic sensing, should be made. Account to this point of view, actual hydrophone was fabricated. Index guiding PCF was used, the fiber core is solid silicon dioxide (SiO2), and the cladding is SiO2 filled with lots of periodical transverse circular air hollows. The PCF, mounted on an air-backed mandrel for structural sensitivity enhancement, was used as a sensing arm of the fiber Michelson interferometer. The other arm, so called reference arm, was made of SMF. Faraday rotator mirrors (FRM) were spliced in the end of each interferometric arm account for polarization induced phase fading, which is a common scheme in fiber interferometric sensing systems. A similar hydrophone, with all the same structure except that the PCF was exchanged into SMF, was also fabrication to make the contrast. The narrowlinewidth and frequency-tunable optical fiber laser was used to achieve high accuracy optical interferometric measurement. Meanwhile, the phase generated carrier (PGC) modulation-demodulation scheme was adopted to interrogate the measurand signal. Experiment was done by using acoustic standing-wave test apparatus. Linearity characteristics of the two hydrophones were measured at frequency 100Hz, 500Hz, and 1000Hz, experimental results showed that the maximum error of the linearity was 10%, a little larger than the theoretical results. Pressure sensitivities of the PCF hydrophone and the SMF hydrophone were measured using a reference standard PZT hydrophone in the frequency range from 20 Hz to 1600 Hz, the measurement data showed that the sensitivity of the PCF hydrophone was about -162.8 dB re. rad/μPa, with a

  9. Synthetic Aperture Radar (SAR) data processing

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  11. a Modified Method for Polarimetric SAR Calibration Algorithm

    NASA Astrophysics Data System (ADS)

    Liao, L.; Li, P.; Yang, J.

    2013-07-01

    Present fully polarimetric synthetic aperture radar (SAR) systems often update calibration techniques to further enhance the accuracy to the polarimetric data. In this paper, we propose a modified method to estimate the value of crosstalk based on the corrected observed value. Since Ainsworth calibration algorithm firstly set the value of k to be one. And the value of k relates to the copolarization channel imbalance .We consider the effects of value of k and analyze it. Through comparison to crosstalk results between the stimulated parameters and the estimated parameters, we assume high co-polarization channel imbalance will be obviously to affect crosstalk results. Then, used covariance observation value of the initial value of k rewrites the model to solve related parameters. And crosstalk parameter is calculated by the same iterative method. To verify the effect of the modified calibration method, this letter compares the accuracy of the two methods using the simulated polarimetric SAR data and Chinese airborne X-band polarimetric SAR data. The results confirm that the modified method tends to get more accurate crosstalk results.

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

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  13. Molecular histopathology by nonlinear interferometric vibrational imaging

    NASA Astrophysics Data System (ADS)

    Boppart, Stephen A.

    2011-07-01

    A rapid label-free approach for molecular histopathology is presented and reviewed. Broadband vibrational spectra are generated by nonlinear interferometric vibrational imaging (NIVI), a coherent anti-Stokes Raman scattering (CARS)- based technique that uses interferometry and signal processing approaches to acquire Raman-like profiles with suppression of the non-resonant background. This allows for the generation of images that provide contrast based on quantitative chemical composition with high spatial and spectral resolution. Algorithms are demonstrated for reducing the diagnostic spectral information into color-coded composite images for the rapid identification of chemical constituents in skin, as well as differentiating normal from abnormal tissue in a pre-clinical tumor model for human breast cancer. This technology and methodology could result in an alternative method to the traditional histological staining and subjective interpretation procedure currently used in the diagnosis of disease, and has the potential for future in vivo molecular histopathology.

  14. VCSELs for interferometric readout of MEMS sensors

    NASA Astrophysics Data System (ADS)

    Serkland, Darwin K.; Geib, Kent M.; Peake, Gregory M.; Keeler, Gordon A.; Shaw, Michael J.; Baker, Michael S.; Okandan, Murat

    2016-03-01

    We report on the development of single-frequency VCSELs (vertical-cavity surface-emitting lasers) for sensing the position of a moving MEMS (micro-electro-mechanical system) object with resolution much less than 1nm. Position measurement is the basis of many different types of MEMS sensors, including accelerometers, gyroscopes, and pressure sensors. Typically, by switching from a traditional capacitive electronic readout to an interferometric optical readout, the resolution can be improved by an order of magnitude with a corresponding improvement in MEMS sensor performance. Because the VCSEL wavelength determines the scale of the position measurement, laser wavelength (frequency) stability is desirable. This paper discusses the impact of VCSEL amplitude and frequency noise on the position measurement.

  15. Four Station Interferometric Radar Observations of Mars

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    Planetary targets have been observed with radar since the late 1950s when it was first used for ranging experiments with the Moon. As telescope size and power increased, it became possible to observe more distant targets (Venus, Mars, and the outer satellites). Inherent to radar observations is the uncertainty as to the source of the reflection, there being two points where range and Doppler rings intersect on a sphere. The use of interferometric methods, first used on the moon with two stations and later on Venus and Mars, solved this problem. We extend the method through the addition of a fourth receiving telescope (thus doubling the number of projected baselines) and integration of the newly available Mars Orbiter Laser Altimeter (MOLA) topographic datasets.

  16. The Space Infrared Interferometric Telescope (SPIRIT)

    NASA Technical Reports Server (NTRS)

    Leisawitz, David

    2005-01-01

    We report preliminary results of a study of the Space Infrared Interferometric Telescope (SPIRIT), a candidate Origins Probe mission. SPIRIT is a two-element Michelson interferometer operating over a nominal wavelength range 25 to 400 microns and offering a powerful combination of spectroscopy and sub-arcsecond angular resolution imaging in a single instrument. With angular resolution comparable to that of JWST and far-IR sensitivity nearly two orders of magnitude better than that of the Spitzer Space Telescope, SPIRIT will measure the resonant structures in exozodi debris disks to find and characterize extrasolar planets; characterize the atmospheres of selected extrasolar gas giant planets; elucidate the evolution of young stellar systems and their planet-forming potential; and track the luminosity evolution and chemical and dust enrichment of galaxies on a cosmological timescale. SPIRIT could be ready to launch as early as 2015. The SPIRIT study is sponsored by NASA under the Origins Science Mission Concept study program.

  17. The Space Infrared Interferometric Telescope (SPIRIT)

    NASA Technical Reports Server (NTRS)

    Rinehart, Stephen

    2007-01-01

    The Space Infrared Interferometric Telescope (SPIRIT) is a candidate NASA Origins Probe Mission. SPIRIT is a two-telescope Michelson interferometer covering wavelengths from 25-400 microns, providing simultaneously high spectral resolution and high angular resolution. With comparable sensitivity to Spitzer, but two orders of magnitude improvement in angular resolution, SPIRIT will enable us to address a wide array of compelling scientific questions, including how planetary systems form in disks and how new planets interact with the disk. Further, SPIRIT will lay the technological groundwork for an array of future interferometry missions with ambitious scientific goals, including the Terrestrial Planet Finder Interferometer / Darwin, and the Submillimeter Probe of the Evolution of Cosmic Structure.

  18. Simultaneous CARS and Interferometric Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Grinstead, Keith D., Jr.; Tedder, Sarah; Cutler, Andrew D.

    2006-01-01

    This paper reports for the first time the combination of a dual-pump coherent anti-Stokes Raman scattering system with an interferometric Rayleigh scattering system (CARS - IRS) to provide time-resolved simultaneous measurement of multiple properties in combustion flows. The system uses spectrally narrow green (seeded Nd:YAG at 532 nm) and yellow (552.9 nm) pump beams and a spectrally-broad red (607 nm) beam as the Stokes beam. A spectrometer and a planar Fabry-Perot interferometer used in the imaging mode are used to record the spectrally broad CARS spectra and the spontaneous Rayleigh scattering spectra, respectively. Time-resolved simultaneous measurement of temperature, absolute mole fractions of N2, O2, and H2, and two components of velocity in a Hencken burner flame were performed to demonstrate the technique.

  19. Interferometric measurements of fine corneal topography

    NASA Astrophysics Data System (ADS)

    Kasprzak, Henryk T.; Kowalik, Waldemar; Jaronski, Jaroslaw W.

    1995-02-01

    The cornea is the most refractive element in the eye. Its refractive power is about 70% of the power of the whole eye. The shape of the cornea is aspheric, and almost always has no rotational symmetry. Even small surface irregularities can cause a perceptible reduction in visual acuity. Standard methods for evaluation of the corneal topography used in clinical practice include keratometry, photokeratoscopy, and computer assisted videokeratography. All of these methods used the principles of geometrical optics, and their accuracy is about 0.25 D. An application of interference phenomenon's to examine the corneal contour map significantly increase the accuracy. Using the interferometric inspection of the corneal shape one can easily observe the fine corneal topography, the fast, dynamic changes of the corneal surface, and the topology of the tear film and its irregularities. The paper presents the Twyman Green interferometer, used in experiments, an example of sequence of interferograms and their 3D presentations.

  20. Combined optical micromanipulation and interferometric topography (COMMIT).

    PubMed

    Sarshar, Mohammad; Lu, Thompson; Anvari, Bahman

    2016-04-01

    Optical tweezers have emerged as a prominent light-based tool for pico-Newton (pN) force microscopy in mechanobiological studies. However, the efficacy of optical tweezers are limited in applications where concurrent metrology of the nano-sized structures under interrogation is essential to the quantitative analysis of its mechanical properties and various mechanotransduction events. We have developed an all-optical platform delivering pN force resolution in parallel with nano-scale structural imaging of the biological sample by combining optical tweezers with interferometric quantitative phase microscopy. These capabilities allow real-time micromanipulation and label-free measurement of sample's nanostructures and nanomechanical responses, opening avenues to a wide range of new research possibilities and applications in biology. PMID:27446661

  1. uvmcmcfit: Parametric models to interferometric data fitter

    NASA Astrophysics Data System (ADS)

    Bussmann, Shane; Leung, Tsz Kuk (Daisy); Conley, Alexander

    2016-06-01

    Uvmcmcfit fits parametric models to interferometric data. It is ideally suited to extract the maximum amount of information from marginally resolved observations with interferometers like the Atacama Large Millimeter Array (ALMA), Submillimeter Array (SMA), and Plateau de Bure Interferometer (PdBI). uvmcmcfit uses emcee (ascl:1303.002) to do Markov Chain Monte Carlo (MCMC) and can measure the goodness of fit from visibilities rather than deconvolved images, an advantage when there is strong gravitational lensing and in other situations. uvmcmcfit includes a pure-Python adaptation of Miriad’s (ascl:1106.007) uvmodel task to generate simulated visibilities given observed visibilities and a model image and a simple ray-tracing routine that allows it to account for both strongly lensed systems (where multiple images of the lensed galaxy are detected) and weakly lensed systems (where only a single image of the lensed galaxy is detected).

  2. Interferometric Plasmonic Lensing with Nanohole Arrays

    SciTech Connect

    Gong, Yu; Joly, Alan G.; El-Khoury, Patrick Z.; Hess, Wayne P.

    2014-12-18

    Nonlinear photoemission electron microscopy (PEEM) of nanohole arrays in gold films maps propagating surface plasmons (PSPs) launched from lithographically patterned structures. Strong near field photoemission patterns are observed in the PEEM images, recorded following low angle of incidence irradiation of nanohole arrays with sub-15 fs laser pulses centered at 780 nm. The recorded photoemission patterns are attributed to constructive and destructive interferences between PSPs launched from the individual nanoholes which comprise the array. By exploiting the wave nature of PSPs, we demonstrate how varying the array geometry (hole diameter, pitch, and number of rows/columns) ultimately yields intense localized photoemission. Through a combination of PEEM and finite-difference time-domain simulations, we identify the optimal array geometry for efficient light coupling and interferometric plasmonic lensing. We show a preliminary application of inteferometric plasmonic lensing by enhancing the photoemission from the vertex of a gold triangle using nanohole array.

  3. Interferometric atmospheric refractive-index environmental monitor.

    PubMed

    Ludman, J E; Ludman, J J; Callahan, H; Caulfield, H J; Watt, D; Sampson, J L; Robinson, J; Davis, S; Hunt, A

    1995-06-20

    Long, open-path, outdoor interferometric measurement of the index of refraction as a function of wavelength (spectral refractivity) requires a number of innovations. These include active compensation for vibration and turbulence. The use of electronic compensation produces an electronic signal that is ideal for extracting data. This allows the appropriate interpretation of those data and the systematic and fast scanning of the spectrum by the use of bandwidths that are intermediate between lasers (narrow bandwidth) and white light (broad bandwidth). An Environmental Interferometer that incorporates these features should be extremely valuable in both pollutant detection and pollutant identification. Spectral refractivity measurements complement the information available from spectral absorption instruments (e.g., a Fourier-transform infrared spectrometer). The Environmental Interferometer currently uses an electronic compensating device with a 1-kHz response time, and therefore rapid spectral scans are feasibe so that it is possible to monitor the time evolution of pollutant events.

  4. Tangential velocity measurement using interferometric MTI radar

    DOEpatents

    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.

  5. Combined optical micromanipulation and interferometric topography (COMMIT)

    PubMed Central

    Sarshar, Mohammad; Lu, Thompson; Anvari, Bahman

    2016-01-01

    Optical tweezers have emerged as a prominent light-based tool for pico-Newton (pN) force microscopy in mechanobiological studies. However, the efficacy of optical tweezers are limited in applications where concurrent metrology of the nano-sized structures under interrogation is essential to the quantitative analysis of its mechanical properties and various mechanotransduction events. We have developed an all-optical platform delivering pN force resolution in parallel with nano-scale structural imaging of the biological sample by combining optical tweezers with interferometric quantitative phase microscopy. These capabilities allow real-time micromanipulation and label-free measurement of sample’s nanostructures and nanomechanical responses, opening avenues to a wide range of new research possibilities and applications in biology. PMID:27446661

  6. The Space Infrared Interferometric Telescope (SPIRIT)

    NASA Technical Reports Server (NTRS)

    Leisawitz, David T.

    2014-01-01

    The far-infrared astrophysics community is eager to follow up Spitzer and Herschel observations with sensitive, high-resolution imaging and spectroscopy, for such measurements are needed to understand merger-driven star formation and chemical enrichment in galaxies, star and planetary system formation, and the development and prevalence of water-bearing planets. The Space Infrared Interferometric Telescope (SPIRIT) is a wide field-of-view space-based spatio-spectral interferometer designed to operate in the 25 to 400 micron wavelength range. This talk will summarize the SPIRIT mission concept, with a focus on the science that motivates it and the technology that enables it. Without mentioning SPIRIT by name, the astrophysics community through the NASA Astrophysics Roadmap Committee recently recommended this mission as the first in a series of space-based interferometers. Data from a laboratory testbed interferometer will be used to illustrate how the spatio-spectral interferometry technique works.

  7. Evaluating SAR polarization modes at L-band for forest classification purposes in Eastern Amazon, Brazil

    NASA Astrophysics Data System (ADS)

    Liesenberg, Veraldo; Gloaguen, Richard

    2013-04-01

    Single, interferometric dual, and quad-polarization mode data were evaluated for the characterization and classification of seven land use classes in an area with shifting cultivation practices located in the Eastern Amazon (Brazil). The Advanced Land-Observing Satellite (ALOS) Phased Array L-band Synthetic Aperture Radar (PALSAR) data were acquired during a six month interval. A clear-sky Landsat-5/TM image acquired at the same period was used as additional ground reference and as ancillary input data in the classification scheme. We evaluated backscattering intensity, polarimetric features, interferometric coherence and texture parameters for classification purposes using support vector machines (SVM) and feature selection. Results showed that the forest classes were characterized by low temporal backscattering intensity variability, low coherence and high entropy. Quad polarization mode performed better than dual and single polarizations but overall accuracies remain low and were affected by precipitation events on the date and prior SAR date acquisition. Misclassifications were reduced by integrating Landsat data and an overall accuracy of 85% was attained. The integration of Landsat to both quad and dual polarization modes showed similarity at the 5% significance level. SVM was not affected by SAR dimensionality and feature selection technique reveals that co-polarized channels as well as SAR derived parameters such as Alpha-Entropy decomposition were important ranked features after Landsat' near-infrared and green bands. We show that in absence of Landsat data, polarimetric features extracted from quad-polarization L-band increase classification accuracies when compared to single and dual polarization alone. We argue that the joint analysis of SAR and their derived parameters with optical data performs even better and thus encourage the further development of joint techniques under the Reducing Emissions from Deforestation and Degradation (REDD) mechanism.

  8. Development of the interferometrical scanning probe microscope

    NASA Astrophysics Data System (ADS)

    Dorozhovets, N.; Hausotte, T.; Hofmann, N.; Manske, E.; Jäger, G.

    2006-08-01

    Many scanning probe microscopes (SPMs) are used as image acquisition tools in such industries as microelectronics, micromechanics, lithography and biotechnology. Conventional SPMs use piezoelectric actuators in order to move either the sample or the probe. The voltage across the piezos is taken as a position indicator. However, it is known that piezos suffer from hysteresis, and from time- and temperature-dependent creep. A solution to this problem is provided by accurate, traceable measurement of the cantilever position. An exact dimensional measurement can only take place via direct comparison with a well-known reference. The traceability of the SPM can be achieved using an interferometer, traceable to the 633 nm wavelength of the He-Ne laser. For accurate measurements the position of the cantilever must be measured in addition to the torsion and bending. This article shows the basic SPM principle as well as the addition of a cantilever position detection system. This system has been realized with a special interferometer with a quadrant diode to detect the cantilever torsion and bending. The measuring beam is focused on the cantilever backside using a lens. The reflected laser beam is split and evaluated; one part of the beam is used for the interferometrical position measurement with the other part focused onto a quadrant diode. Due to the structure of the interferometrical SPM, it can be installed in many different positioning systems with large measuring ranges, including a nanopositioning and nanomeasuring machine (NPM machine), developed at the Institute of Process Measurement and Sensor Technology of the Technische Universitaet Ilmenau.

  9. Recent developments of interferometric wavefront sensing

    NASA Astrophysics Data System (ADS)

    Liu, Dong; Yang, Yongying; Chen, Xiaoyu; Ling, Tong; Zhang, Lei; Bai, Jian; Shen, Yibing

    2015-08-01

    Recent trends of interferometric wavefront sensing tend to focus on high precision, anti-vibration, compact, along with much more involved of electric and computer technology. And the optical principles employed not only limit to interference but also include diffraction, scattering, polarization, etc. In this paper, some selected examples basing on the research works in our group will be given to illustrate the trends mentioned above. To achieve extra high accuracy, phase-shifting point diffraction interferometry (PS-PDI) is believed to be a good candidate as it employs a nearly perfect point diffraction spherical wavefront as the reference and also takes advantage of the high precision of phase-shifting algorithms. Cyclic radial shearing interferometry (C-RSI) successively demonstrate the anti-vibration characteristic and can diagnose transient wavefront with only one single shot by employing a three-mirror common-path configuration and a synchronizing system. In contrast sharply with those early interferometers, interferometers with very compact configuration are more suitable to develop portable wavefront sensing instruments. Cross-grating lateral shearing interferometer (CG-LSI) is a very compact interferometer that adopts a cross-grating of millimeters to produce lateral shearing of the diffraction wave of the test wavefront. Be aware that, computer technique has been used a lot in all of the above interferometers but the non-null annual sub-aperture stitching interferometer (NASSI) for general aspheric surface testing mostly relies on the computer model of the physical interferometer setup and iterative ray-tracing optimization. The principles of the above mentioned interferometric wavefront sensing methods would be given in detail.

  10. The 2014 interferometric imaging beauty contest

    NASA Astrophysics Data System (ADS)

    Monnier, John D.; Berger, Jean-Philippe; Le Bouquin, Jean-Baptiste; Tuthill, Peter G.; Wittkowski, Markus; Grellmann, Rebekka; Müller, André; Renganswany, Sridhar; Hummel, Christian; Hofmann, Karl-Heinz; Schertl, Dieter; Weigelt, Gerd; Young, John; Buscher, David; Sanchez-Bermudez, Joel; Alberdi, Antxon; Schoedel, Rainer; Köhler, Rainer; Soulez, Ferréol; Thiébaut, Éric; Kluska, Jacques; Malbet, Fabien; Duvert, Gilles; Kraus, Stefan; Kloppenborg, Brian K.; Baron, Fabien; de Wit, Willem-Jan; Rivinius, Thomas; Merand, Antoine

    2014-07-01

    Here we present the results of the 6th biennial optical interferometry imaging beauty contest. Taking advantage of a unique opportunity, the red supergiant VY CMa and the Mira variable R Car were observed in the astronomical H-band with three 4-telescope configurations of the VLTI-AT array using the PIONIER instrument. The community was invited to participate in the subsequent image reconstruction and interpretation phases of the project. Ten groups submitted entries to the beauty contest, and we found reasonable consistency between images obtained from independent workers using quite different algorithms. We also found that significant differences existed between the submitted images, much greater than in past beauty contests that were all based on simulated data. A novel crowd-sourcing" method allowed consensus median images to be constructed, filtering likely artifacts and retaining real features." We definitively detect strong spots on the surfaces of both stars as well as distinct circumstellar shells of emission (likely water/CO) around R Car. In a close contest, Joel Sanchez (IAA-CSIC/Spain) was named the winner of the 2014 interferometric imaging beauty contest. This process has shown that new comers" can use publicly-available imaging software to interpret VLTI/PIONIER imaging data, as long as sufficient observations are taken to have complete uv coverage { a luxury that is often missing. We urge proposers to request adequate observing nights to collect sufficient data for imaging and for time allocation committees to recognise the importance of uv coverage for reliable interpretation of interferometric data. We believe that the result of the proposed broad international project will contribute to inspiring trust in the image reconstruction processes in optical interferometry.

  11. Acoustic Location of Lightning Using Interferometric Techniques

    NASA Astrophysics Data System (ADS)

    Erives, H.; Arechiga, R. O.; Stock, M.; Lapierre, J. L.; Edens, H. E.; Stringer, A.; Rison, W.; Thomas, R. J.

    2013-12-01

    Acoustic arrays have been used to accurately locate thunder sources in lightning flashes. The acoustic arrays located around the Magdalena mountains of central New Mexico produce locations which compare quite well with source locations provided by the New Mexico Tech Lightning Mapping Array. These arrays utilize 3 outer microphones surrounding a 4th microphone located at the center, The location is computed by band-passing the signal to remove noise, and then computing the cross correlating the outer 3 microphones with respect the center reference microphone. While this method works very well, it works best on signals with high signal to noise ratios; weaker signals are not as well located. Therefore, methods are being explored to improve the location accuracy and detection efficiency of the acoustic location systems. The signal received by acoustic arrays is strikingly similar to th signal received by radio frequency interferometers. Both acoustic location systems and radio frequency interferometers make coherent measurements of a signal arriving at a number of closely spaced antennas. And both acoustic and interferometric systems then correlate these signals between pairs of receivers to determine the direction to the source of the received signal. The primary difference between the two systems is the velocity of propagation of the emission, which is much slower for sound. Therefore, the same frequency based techniques that have been used quite successfully with radio interferometers should be applicable to acoustic based measurements as well. The results presented here are comparisons between the location results obtained with current cross correlation method and techniques developed for radio frequency interferometers applied to acoustic signals. The data were obtained during the summer 2013 storm season using multiple arrays sensitive to both infrasonic frequency and audio frequency acoustic emissions from lightning. Preliminary results show that

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

  13. Relative elastic interferometric imaging for microseismic source location

    NASA Astrophysics Data System (ADS)

    Li, Lei; Chen, Hao; Wang, Xiuming

    2016-10-01

    Combining a relative location method and seismic interferometric imaging, a relative elastic interferometric imaging method for microseismic source location is proposed. In the method, the information of a known event (the main event) is fully used to improve the location precision of the unknown events (the target events). First, the principles of both conventional and the relative interferometric imaging methods are analyzed. Traveltime differences from the position of the same potential event to different receivers are used in direct interferometric imaging, while relative interferometric imaging utilizes those of different events to the same receiver. Second, 2D and 3D numerical experiments demonstrate the feasibility of this newly proposed method in locating a single microseismic event. Envelopes of cross-correlation traces are utilized to eliminate the effects of changing polarities resulting from the source mechanism and receiver configuration. Finally, the location precision of the relative and conventional interferometric imaging methods are compared, and it indicates that the former hold both advantages of the relative method and interferometric imaging. Namely, it can adapt to comparatively high velocity error and low signal-to-noise ratio (SNR) microseismic data. Moreover, since there is no arrival time picking and fewer cross-correlograms are imaged, the method also significantly saves computational expense.

  14. Earth observing SAR data processing systems at the Jet Propulsion Laboratory - Seasat to EOS SAR

    NASA Technical Reports Server (NTRS)

    Nichols, David A.; Curlander, John C.

    1991-01-01

    The evolution of SAR digital data processing and management ground systems developed at the JPL for earth science missions is discussed. Attention is given to the SAR ground data system requirements, the early data processing systems, the Seasat SAR system, and the SIR-B data processing system. Special consideration is given to two currently operational SAR data systems: the JPL aircraft SAR processing system that flies on the NASA DC-8 and the Alaska SAR Facility at Fairbanks.

  15. Millimeter-Wave Airborne Interferometry for High-accuracy Topography Mapping

    NASA Astrophysics Data System (ADS)

    Moller, D.; Hensley, S.; Wu, X.; Rodriguez, E.

    2011-12-01

    In April 2009, an airborne Ka-band single pass interferometric SAR (GLISTIN-A) was demonstrated as a modification to the UAVSAR system. GLISTIN-A was developed under the NASA International Polar Year program to demonstrate swath-mapping for ice-surface topography. Instrument performance confirmed swath widths over the ice between 5-7km, with height precisions ranging from 30cm-3m at a 3m x 3m posting. However processing challenges were encountered on several fronts to achieve the required accuracies including, aircraft motion sensitivity, multipath and systematic drifts. A combination of processor optimization, a modified phase-screen and motion-compensation implementations were able to minimize the impact of these systematic error sources. Funded by the NASA Earth Science Technology Office, upgrades are currently underway to improve the performance (swath >10km) and portability of GLISTIN-A. The upgraded GLISTIN-A will be compatible with the GlobalHawk making Antarctica regional mapping feasible. Beyond this, the surface water and ocean topography (SWOT) mission slated for launch in 2019, needs an airborne sensor to support pre-mission phenomenology measurements and mission calibration and valibration (cal/val). SWOT is unique and distinct from precursor ocean altimetry missions in some notable regards: 1) 100km+ of swath will provide complete ocean elevation coverage, 2) in addition the land surface water will be mapped for storage measurement and discharge estimation and 3) Ka-band single-pass interferometry will produce the 2-D water surface elevation (WSE) maps. In support of SWOT, en-route to Greenland, GLISTIN-A collected a limited amount of data over surface-water targets in North Dakota. While instructive as a preliminary validation of Ka-band interferometry over inland water bodies, further application is limited because GLISTIN-A itself was not designed to address SWOT needs. While ideal for a the ice topography mapping application, the combination of

  16. Mars Airborne Prospecting Spectrometer

    NASA Astrophysics Data System (ADS)

    Steinkraus, J. M.; Wright, M. W.; Rheingans, B. E.; Steinkraus, D. E.; George, W. P.; Aljabri, A.; Hall, J. L.; Scott, D. C.

    2012-06-01

    One novel approach towards addressing the need for innovative instrumentation and investigation approaches is the integration of a suite of four spectrometer systems to form the Mars Airborne Prospecting Spectrometers (MAPS) for prospecting on Mars.

  17. Landslide monitoring by Terrestrial SAR Interferometry: critical analysis of different data processing approaches

    NASA Astrophysics Data System (ADS)

    Brunetti, Alessandro; Crosetto, Michele; Mazzanti, Paolo; Monserrat, Oriol

    2015-04-01

    In last years, Terrestrial Synthetic Aperture Radar Interferometry (TInSAR) became a key technology in the field of landslide and structures/infrastructures displacement monitoring. Thanks to undoubted advantages such as i) widespread information, ii) fully remote applicability over long ranges and iii) high accuracy, this technique promises to be a very effective solution for a lot of geological and engineering issues. Even if this technique was born for interferometric analyses (basing on the phase differences between SAR images collected at different time intervals), recent studies demonstrated its reliability also with non-interferometric processing approaches, based on the amplitude tracking of high-reflectivity objects (i.e. corner reflectors). Furthermore, both approaches can be used for both continuous and discontinuous monitoring, thus opening to a wide spectrum of applications for different purposes. The aim of this work is to provide information about the reliability and the accuracy of TInSAR technique in its different kind of applications. In the frame of this work, two case studies of landslides monitored with a continuous acquisition mode (about 5 minutes sampling rate) have been investigated. The first case study consists of superficial instability problems mainly related to huge rainfalls and works, leading to non-linear displacements up to 10 mm/day. In order to assess the impact of discontinuous acquisition mode, data subsampling of one data/day for an overall monitoring period of about 3 months has been performed. The comparison between discontinuous and continuous interferometric processing approach allowed the identification of some aliasing and ambiguity problems in the discontinuous approach, especially in periods when high displacement rates were affecting the slope. Nevertheless, in most of such cases, it was still possible to provide qualitative information about criticalities, even if a precise estimation of displacement entities was

  18. TerraSAR-X mission

    NASA Astrophysics Data System (ADS)

    Werninghaus, Rolf

    2004-01-01

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

  19. Observations and Mitigation of RFI in ALOS PALSAR SAR Data; Implications for the Desdyni Mission

    NASA Technical Reports Server (NTRS)

    Rosen, Paul A.; Hensley, Scott; Le, Charles

    2008-01-01

    Initial examination of ALOS PALSAR synthetic aperture radar (SAR) data has indicated significant radio frequency interference (RFI) in several geographic locations around the world. RFI causes significant reduction in image contrast, introduces periodic and quasi-periodic image artifacts, and introduces significant phase noise in repeat pass interferometric data reduction. The US National Research Council Decadal Survey of Earth Science has recommended DESDynI, a Deformation, Ecosystems, and Dynamics of Ice satellite mission comprising an L-band polarimetric radar configured for repeat pass interferometry. There is considerable interest internationally in other future L-band and lower frequency systems as well. Therefore the issues of prevalence and possibilities of mitigation of RFI in these crowded frequency bands is of considerable interest. RFI is observed in ALOS PALSAR in California, USA, and in southern Egypt in data examined to date. Application of several techniques for removing it from the data prior to SAR image formation, ranging from straightforward spectral normalization to time-domain, multi-phase filtering techniques are considered. Considerable experience has been gained from the removal of RFI from P-band acquired by the GeoSAR system. These techniques applied to the PALSAR data are most successful when the bandwidth of any particular spectral component of the RFI is narrow. Performance impacts for SAR imagery and interferograms are considered in the context of DESDynI measurement requirements.

  20. Simulation Studies of the Effect of Forest Spatial Structure on InSAR Signature

    NASA Technical Reports Server (NTRS)

    Sun, Guoqing; Liu, Dawei; Ranson, K. Jon; Koetz, Benjamin

    2007-01-01

    The height of scattering phase retrieved from InSAR data is considered being correlated with the tree height and the spatial structure of the forest stand. Though some researchers have used simple backscattering models to estimate tree height from the height of scattering center, the effect of forest spatial structure on InSAR data is not well understood yet. A three-dimensional coherent radar backscattering model for forest canopies based on realistic three-dimensional scene was used to investigate the effect in this paper. The realistic spatial structure of forest canopies was established either by field measurements (stem map) or through use of forest growth model. Field measurements or a forest growth model parameterized using local environmental parameters provides information of forest species composition and tree sizes in certain growth phases. A fractal tree model (L-system) was used to simulate individual 3- D tree structure of different ages or heights. Trees were positioned in a stand in certain patterns resulting in a 3-D medium of discrete scatterers. The radar coherent backscatter model took the 3-D forest scene as input and simulates the coherent radar backscattering signature. Interferometric SAR images of 3D scenes were simulated and heights of scattering phase centers were estimated from the simulated InSAR data. The effects of tree height, crown cover, crown depth, and the spatial distribution patterns of trees on the scattering phase center were analyzed. The results will be presented in the paper.

  1. First In-Orbit Experience of TerraSAR-X Flight Dynamics Operations

    NASA Technical Reports Server (NTRS)

    Kahle, R.; Kazeminejad, B.; Kirschner, M.; Yoon, Y.; Kiehling, R.; D'Amico, S.

    2007-01-01

    TerraSAR-X is an advanced synthetic aperture radar satellite system for scientific and commercial applications that is realized in a public-private partnership between the German Aerospace Center (DLR) and the Astrium GmbH. TerraSAR-X was launched at June 15, 2007 on top of a Russian DNEPR-1 rocket into a 514 km sun-synchronous dusk-dawn orbit with an 11-day repeat cycle and will be operated for a period of at least 5 years during which it will provide high resolution SAR-data in the X-band. Due to the objectives of the interferometric campaigns the satellite has to comply to tight orbit control requirements, which are formulated in the form of a 250 m toroidal tube around a pre-flight determined reference trajectory (see [1] for details). The acquisition of the reference orbit was one of the main and key activities during the Launch and Early Orbit Phase (LEOP) and had to compensate for both injection errors and spacecraft safe mode attitude control thruster activities. The paper summarizes the activities of GSOC flight dynamics team during both LEOP and early Commissioning Phase, where the main tasks have been 1) the first-acquisition support via angle-tracking and GPS-based orbit determination, 2) maneuver planning for target orbit acquisition and maintenance, and 3) precise orbit and attitude determination for SAR processing support. Furthermore, a presentation on the achieved results and encountered problems will be addressed.

  2. Dynamic Deformation of ETNA Volcano Observed by GPS and SAR Interferometry

    NASA Technical Reports Server (NTRS)

    Lundgren, P.; Rosen, P.; Webb, F.; Tesauro, M.; Lanari, R.; Sansosi, E.; Puglisi, G.; Bonforte, A.; Coltelli, M.

    1999-01-01

    Synthetic aperture radar (SAR) interferometry and GPS have shown that during the quiescent period from 1993-1995 Mt. Etna volcano, Italy, inflated. Since the initiation of eruptive activity since late 1995 the deformation has been more contentious. We will explore the detailed deformation during the period from 1995-1996 spanning the late stages of inflation and the beginning of eruptive activity. We use SAR interferometry and GPS data to measure the volcano deformation. We invert the observed deformation for both simple point source. le crack elastic sources or if warranted for a spheroidal pressure So In particular, we will examine the evolution of the inflation and the transition to a lesser deflation observed at the end of 1995. We use ERS-1/2 SAR data from both ascending and descending passes to allow for dense temporal 'sampling of the deformation and to allow us to critically assess atmospheric noise. Preliminary results from interferometry suggest that the inflation rate accelerated prior to resumption of activity in 1995, while GPS data suggest a more steady inflation with some fluctuation following the start of activity. This study will compare and contrast the interferometric SAR and GPS results and will address the strengths and weaknesses of each technique towards volcano deformation studies.

  3. e-Collaboration for Earth observation (E-CEO): the Cloud4SAR interferometry data challenge

    NASA Astrophysics Data System (ADS)

    Casu, Francesco; Manunta, Michele; Boissier, Enguerran; Brito, Fabrice; Aas, Christina; Lavender, Samantha; Ribeiro, Rita; Farres, Jordi

    2014-05-01

    The e-Collaboration for Earth Observation (E-CEO) project addresses the technologies and architectures needed to provide a collaborative research Platform for automating data mining and processing, and information extraction experiments. The Platform serves for the implementation of Data Challenge Contests focusing on Information Extraction for Earth Observations (EO) applications. The possibility to implement multiple processors within a Common Software Environment facilitates the validation, evaluation and transparent peer comparison among different methodologies, which is one of the main requirements rose by scientists who develop algorithms in the EO field. In this scenario, we set up a Data Challenge, referred to as Cloud4SAR (http://wiki.services.eoportal.org/tiki-index.php?page=ECEO), to foster the deployment of Interferometric SAR (InSAR) processing chains within a Cloud Computing platform. While a large variety of InSAR processing software tools are available, they require a high level of expertise and a complex user interaction to be effectively run. Computing a co-seismic interferogram or a 20-years deformation time series on a volcanic area are not easy tasks to be performed in a fully unsupervised way and/or in very short time (hours or less). Benefiting from ESA's E-CEO platform, participants can optimise algorithms on a Virtual Sandbox environment without being expert programmers, and compute results on high performing Cloud platforms. Cloud4SAR requires solving a relatively easy InSAR problem by trying to maximize the exploitation of the processing capabilities provided by a Cloud Computing infrastructure. The proposed challenge offers two different frameworks, each dedicated to participants with different skills, identified as Beginners and Experts. For both of them, the contest mainly resides in the degree of automation of the deployed algorithms, no matter which one is used, as well as in the capability of taking effective benefit from a parallel

  4. Crystal structure of the SarS protein from Staphylococcus aureus.

    PubMed

    Li, Ronggui; Manna, Adhar C; Dai, Shaodong; Cheung, Ambrose L; Zhang, Gongyi

    2003-07-01

    The expression of virulence determinants in Staphylococcus aureus is controlled by global regulatory loci (e.g., sarA and agr). One of these determinants, protein A (spa), is activated by sarS, which encodes a 250-residue DNA-binding protein. Genetic analysis indicated that the agr locus likely mediates spa repression by suppressing the transcription of sarS. Contrary to SarA and SarR, which require homodimer formation for proper function, SarS is unusual within the SarA protein family in that it contains two homologous halves, with each half sharing sequence similarity to SarA and SarR. Here we report the 2.2 A resolution X-ray crystal structure of the SarS protein. SarS has folds similar to those of SarR and, quite plausibly, the native SarA structure. Two typical winged-helix DNA-binding domains are connected by a well-ordered loop. The interactions between the two domains are extensive and conserved. The putative DNA-binding surface is highly positively charged. In contrast, negatively charged patches are located opposite to the DNA-binding surface. Furthermore, sequence alignment and structural comparison revealed that MarR has folds similar to those of SarR and SarS. Members of the MarR protein family have previously been implicated in the negative regulation of an efflux pump involved in multiple antibiotic resistance in many gram-negative species. We propose that MarR also belongs to the winged-helix protein family and has a similar mode of DNA binding as SarR and SarS and possibly the entire SarA protein family member. Based on the structural differences of SarR, SarS, and MarR, we further classified these winged-helix proteins to three subfamilies, SarA, SarS, and MarR. Finally, a possible transcription regulation mechanism is proposed.

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

    NASA Astrophysics Data System (ADS)

    Skriver, H.

    2013-12-01

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

  6. Landslide risk assessment with multi pass DInSAR analysis and error suppressing approach

    NASA Astrophysics Data System (ADS)

    yun, H.; Kim, J.; Lin, S.; Choi, Y.

    2013-12-01

    Landslide is one of the most dreadful natural hazards and the prime risk source causing lethal damages in many countries. In spite of various attempts to measure the landslide susceptibility by the remote sensed method including Differential Interferometric SAR (DInSAR) analysis, the construction of reliable forecasting systems still remains unsolved. Thus, we tackled the problem of DInSAR analysis for monitoring landslide risk over the mountainous areas where InSAR observations are usually contaminated by the orographic effects and other error elements. In order to measure the correct surface deformation which might be a prelude of landslide, time series analysis and atmospheric correction of DInSAR interferograms were conducted and crossly validated. The target area of this experiment is the eastern part of Korean peninsula centered in Uljin. In there, the landslide originated by the geomorphic factors such as high sloped topography and localized torrential down pour is critical issue. The landslide cases frequently occurred in the cutting side of mountainous area by the anthropogenic construction activities. Although high precision DInSAR measurements for monitoring the landslide risks are essential in such circumstances, it is difficult to attain sufficient enough accuracy because of the external factors inducing the error component in electromagnetic wave propagation. For instance, the local climate characteristics such as orographic effect and the proximity to seashore can produce the significant anomalies in the water vapor distribution and consequently result in the error components of InSAR phase angle measurements. Moreover the high altitude parts of target area cause the stratified tropospheric delay error in DInSAR measurement. After all, the improved DInSAR approaches to cope all above obstacles are highly necessary. Thus we employed two approaches i.e. StaMPS/MTI (Stanford Method for Persistent Scatterers/Multi-Temporal InSAR, Hopper et al., 2007

  7. Land subsidence in the Yangtze River Delta, China revealed from multi-frequency SAR Interferometry

    NASA Astrophysics Data System (ADS)

    Li, Zhenhong; Motagh, Mahdi; Yu, Jun; Gong, Xulong; Wu, Jianqiang; Zhu, Yefei; Chen, Huogen; Zhang, Dengming; Xu, Yulin

    2014-05-01

    Land subsidence is a major worldwide hazard, and its principal causes are subsurface fluid withdrawal, drainage of organic soils, sinkholes, underground mining, hydrocompaction, thawing permafrost, and natural consolidation. Land subsidence causes many problems including: damage to public facilities such as bridges, roads, railroads, electric power lines, underground pipes; damage to private and public buildings; and in some cases of low-lying land, can increase the risk of coastal flooding from storm surges and rising sea-levels. In China, approximately 48600 km2 of land, an area roughly 30 times of the size of the Greater London, has subsided (nearly 50 cities across 16 provinces), and the annual direct economic loss is estimated to be more than RMB 100 million (~12 million). It is believed that the Suzhou-Wuxi-Changzhou region within the Yangtze River Delta is the most severely affected area for subsidence hazards in China. With its global coverage and all-weather imaging capability, Interferometric SAR (InSAR) is revolutionizing our ability to image the Earth's surface and the evolution of its shape over time. In this paper, an advanced InSAR time series technique, InSAR TS + AEM, has been employed to analysed ERS (C-band), Envisat (C-band) and TerraSAR-X (X-band) data collected over the Suzhou-Wuxi-Changzhou region during the period from 1992 to 2013. Validation with precise levelling and GPS data suggest: (1) the accuracy of the InSAR-derived mean velocity measurements is 1-3 mm/yr; (2) InSAR-derived displacements agreed with precise levelling with root mean square errors around 5 mm. It is evident that InSAR TS + AEM can be used to image the evolution of deformation patterns in the Suzhou-Wuxi-Changzhou region over time: the maximum mean velocity decreased from ~12 cm/yr during the period of 1992-1993 to ~2 cm/yr in 2003-2013. This is believed to be a result of the prohibition of groundwater use carried out by Jiangsu provincial government. The combination

  8. Spectroscopic and Interferometric Measurements of Nine K Giant Stars

    NASA Astrophysics Data System (ADS)

    Baines, Ellyn K.; Döllinger, Michaela P.; Guenther, Eike W.; Hatzes, Artie P.; Hrudkovu, Marie; van Belle, Gerard T.

    2016-09-01

    We present spectroscopic and interferometric measurements for a sample of nine K giant stars. These targets are of particular interest because they are slated for stellar oscillation observations. Our improved parameters will directly translate into reduced errors in the final masses for these stars when interferometric radii and asteroseismic densities are combined. Here, we determine each star’s limb-darkened angular diameter, physical radius, luminosity, bolometric flux, effective temperature, surface gravity, metallicity, and mass. When we compare our interferometric and spectroscopic results, we find no systematic offsets in the diameters and the values generally agree within the errors. Our interferometric temperatures for seven of the nine stars are hotter than those determined from spectroscopy with an average difference of about 380 K.

  9. An Interferometric Search for Bright Companions to 51 Pegasi

    NASA Technical Reports Server (NTRS)

    Boden, A. F.; van Belle, G. T.; Colavita, M. M.; Dumont, P. J.; Gubler, J.; Koresko, C. D.; Kulkarni, S. R.; Lane, B. F.; Mobley, D. W.; Shao, M.; Wallace, J. K.

    1998-01-01

    We report on a near-infrared, long-baseline interferometric search for luminous companions to the star 51 Pegasi conducted with the Palomar Testbed Interferometer. Our data is completely consistent with a single-star hypothesis.

  10. A TACSAT SAR concept

    NASA Astrophysics Data System (ADS)

    Hall, C. D.; Baker, C. J.; Keyte, G. E.; Murphy, L. M.

    1993-02-01

    The payload concept covered is that of a low cost, high performance radar sensor capable of detecting and recognizing static objects within an imaged scene of the Earth's surface using the Synthetic Aperture Radar (SAR) technique. The overall system is integrated with a TACSAT platform in Low Earth Orbit (LEO) and, although only passing reference is made to this feature, the radar could also have a capability for the detection of Ground Moving Targets (GMTI). A parametric review of such a sensor in the light of the target and background features to be observed is provided. A design concept is included showing the possible hardware realization of a candidate system, as well as budgets for the mass, size, power, and pointing requirements of the instrument. Additional design features considered are the influence that short duration missions may have on hardware redundancy and the effect of short, low duty-cycle observation periods on solar array and battery sizing. The way towards a low cost R and D demonstrator system allowing a practical investigation of the key techniques and technologies is addressed.

  11. Sensitivity of earthquake source inversions to atmospheric noise and corrections of InSAR data

    NASA Astrophysics Data System (ADS)

    Scott, Chelsea Phipps; Lohman, Rowena Benfer

    2016-05-01

    Tropospheric phase delays pose a major challenge to InSAR (interferometric synthetic aperture radar)-based studies of tectonic deformation. One approach to the mitigation of effects from tropospheric noise is the application of elevation-dependent corrections based on empirical fits between elevation and interferometric phase. We quantify the effects of corrections with a range of complexity on inferred earthquake source parameters using synthetic interferograms with known atmospheric characteristics. We infer statistical properties of the stratified component of the atmosphere using pressure, temperature, and water vapor data from the North America Regional Reanalysis model over our region of interest in the Basin and Range province of the western United States. The statistics of the simulated atmospheric turbulence are estimated from InSAR and Global Positioning System data. We demonstrate potentially significant improvements in the precision of earthquake magnitude, depth, and dip estimates for several synthetic earthquake focal mechanisms following a correction for spatially variable atmospheric characteristics, relative to cases where the correction is based on a uniform delay versus elevation relationship or where no correction is applied. We apply our approach to the 1992 M5.6 Little Skull Mountain, Nevada, earthquake and demonstrate that the earthquake source parameter error bounds decrease in size after applying the atmospheric corrections. Our approach for evaluating the impact of atmospheric noise on inferred fault parameters is easily adaptable to other regions and source mechanisms.

  12. Fine Resolution Topographic Mapping of the Jovian Moons: A Ka-Band High Resolution Topographic Mapping Interferometric Synthetic Aperture Radar

    NASA Technical Reports Server (NTRS)

    Madsen, S. N.; Carsey, F. D.; Turtle, E. P.

    2003-01-01

    The topographic data set obtained by MOLA has provided an unprecedented level of information about Mars' geologic features. The proposed flight of JIMO provides an opportunity to accomplish a similar mapping of and comparable scientific discovery for the Jovian moons through use of an interferometric imaging radar analogous to the Shuttle radar that recently generated a new topographic map of Earth. A Ka-band single pass across-track synthetic aperture radar (SAR) interferometer can provide very high resolution surface elevation maps. The concept would use two antennas mounted at the ends of a deployable boom (similar to the Shuttle Radar Topographic Mapper) extended orthogonal to the direction of flight. Assuming an orbit altitude of approximately 100km and a ground velocity of approximately 1.5 km/sec, horizontal resolutions at the 10 meter level and vertical resolutions at the sub-meter level are possible.

  13. Fine resolution topographic mapping of the Jovian moons: a Ka-band high resolution topographic mapping interferometric synthetic aperture radar

    NASA Technical Reports Server (NTRS)

    Madsen, Soren N.; Carsey, Frank D.; Turtle, Elizabeth P.

    2003-01-01

    The topographic data set obtained by MOLA has provided an unprecedented level of information about Mars' geologic features. The proposed flight of JIMO provides an opportunity to accomplish a similar mapping of and comparable scientific discovery for the Jovian moons through us of an interferometric imaging radar analogous to the Shuttle radar that recently generated a new topographic map of Earth. A Ka-band single pass across-track synthetic aperture radar (SAR) interferometer can provide very high resolution surface elevation maps. The concept would use two antennas mounted at the ends of a deployable boom (similar to the Shuttle Radar Topographic Mapper) extended orthogonal to the direction of flight. Assuming an orbit altitude of approximately 100 km and a ground velocity of approximately 1.5 km/sec, horizontal resolutions at the 10 meter level and vertical resolutions at the sub-meter level are possible.

  14. Reservoir monitoring and characterization using satellite geodetic data: Interferometric Synthetic Aperture Radar observations from the Krechba field, Algeria

    SciTech Connect

    Vasco, D.W.; Ferretti, Alessandro; Novali, Fabrizio

    2008-05-01

    Deformation in the material overlying an active reservoir is used to monitor pressure change at depth. A sequence of pressure field estimates, eleven in all, allow us to construct a measure of diffusive travel time throughout the reservoir. The dense distribution of travel time values means that we can construct an exactly linear inverse problem for reservoir flow properties. Application to Interferometric Synthetic Aperture Radar (InSAR) data gathered over a CO{sub 2} injection in Algeria reveals pressure propagation along two northwest trending corridors. An inversion of the travel times indicates the existence of two northwest-trending high permeability zones. The high permeability features trend in the same direction as the regional fault and fracture zones. Model parameter resolution estimates indicate that the features are well resolved.

  15. Spaceborne radar applications in geology. An introduction to imaging radar and application examples of ERS SAR in geology and geomorphology

    NASA Astrophysics Data System (ADS)

    Fletcher, Karen

    2005-12-01

    This document is intended for geologists who are interested in broadening their knowledge of interpretation of imaging radar data, but also addresses the general public for reference and information. It introduces imaging radar as it may be used by technicians and image interpreters, stressing the use of synthetic aperture radar (SAR) for Earth observation in general and for geology in particular. Interferometric SAR is briefly treated, with some basic and practical hints. An illustrated application study on land subsidence is included. SAR/optical data fusion is explained, with examples of the different methods suggested. The main part of the document, part II, consists of 14 case studies that demonstrate the potential of SAR imagery for geology. These studies cover themes such as the detection and mapping of neotectonic activity, tectonic mapping, and recognition of karst structures, as well as analysis of active lahars and other volcanic events. They look into drainage systems in desert areas, consider lithofacies changes and morphostructure texture analysis, and they demonstrate the geological mapping of active tectonic compression. Finally, the document mentions the key points of the ESA SAR missions. Contacts for further information are also provided.

  16. Spatial-temporal surface deformation of Los Angeles over 2003-2007 from weighted least squares DInSAR

    NASA Astrophysics Data System (ADS)

    Hu, Jun; Li, Zhiwei; Ding, Xiaoli; Zhu, Jianjun; Sun, Qian

    2013-04-01

    The spatial-temporal evolution of surface displacement of Los Angeles area over 2003-2007 is measured with weighted least squares (WLS) small baseline (SB) DInSAR technique. 32 small baseline interferograms are generated from 18 SAR images acquired by the ENVISAT satellite and separated into two independent subsets. An additional interferogram with a longer baseline but good interferometric quality is used to link the two subsets. A time series of displacements with their corresponding standard deviations (STD) are derived from the WLS DInSAR solution by considering the interferometric displacement variances when determining the weighting scheme. Both the long-term trends and the seasonal variations of the displacements in the area are determined in the study and validated with GPS measurements from a number of stations of the Southern California Integrated GPS Network (SCIGN). The mean line-of-sight (LOS) displacement velocity map shows up to 3 cm/year of ground motion and up to 10 cm of accumulated displacements in Santa Fe Springs and -8 cm in Pomona over 2003-2007. Seasonal variations are identified in Santa Ana basin, the San Gabriel valley and the Lytle Creek basin, respectively.

  17. Classification of High Resolution C-Band PolSAR Data on Polarimetric and Texture Features

    NASA Astrophysics Data System (ADS)

    Zhao, Lei; Chen, Erxue; Li, Zengyuan; Feng, Qi; Li, Lan

    2014-11-01

    PolSAR image classification is an important technique in the remote sensing area. For high resolution PolSAR image, polarimetric and texture features are equally important for the high resolution PolSAR image classification. The texture features are mainly extracted through Gray Level Co-occurrence Matrix (GLCM) method, but this method has some deficiencies. First, GLCM method can only work on gray-scale images; Secondly, the number of texture features extracted by GLCM method is generally up dozens, or even hundreds. Too many features may exist larger redundancy and will increase the complexity of classification. Therefore, this paper introduces a new texture feature factor-RK that derived from PolSAR image non-Gaussian statistic model.Using the domestic airborne C-band PolSAR image data, we completed classification combined the polarization and texture characteristics.The results showed that this new texture feature factor-RK can overcome the above drawbacks and can achieve same performance compared with GLCM method.

  18. SAR amplitude probability density function estimation based on a generalized Gaussian model.

    PubMed

    Moser, Gabriele; Zerubia, Josiane; Serpico, Sebastiano B

    2006-06-01

    In the context of remotely sensed data analysis, an important problem is the development of accurate models for the statistics of the pixel intensities. Focusing on synthetic aperture radar (SAR) data, this modeling process turns out to be a crucial task, for instance, for classification or for denoising purposes. In this paper, an innovative parametric estimation methodology for SAR amplitude data is proposed that adopts a generalized Gaussian (GG) model for the complex SAR backscattered signal. A closed-form expression for the corresponding amplitude probability density function (PDF) is derived and a specific parameter estimation algorithm is developed in order to deal with the proposed model. Specifically, the recently proposed "method-of-log-cumulants" (MoLC) is applied, which stems from the adoption of the Mellin transform (instead of the usual Fourier transform) in the computation of characteristic functions and from the corresponding generalization of the concepts of moment and cumulant. For the developed GG-based amplitude model, the resulting MoLC estimates turn out to be numerically feasible and are also analytically proved to be consistent. The proposed parametric approach was validated by using several real ERS-1, XSAR, E-SAR, and NASA/JPL airborne SAR images, and the experimental results prove that the method models the amplitude PDF better than several previously proposed parametric models for backscattering phenomena. PMID:16764268

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  20. Response of interferometric gravitational wave detectors

    SciTech Connect

    Finn, Lee Samuel

    2009-01-15

    The derivation of the response function of an interferometric gravitational wave detector is a paradigmatic calculation in the field of gravitational wave detection. Surprisingly, the standard derivation of the response wave detectors makes several unjustifiable assumptions, both conceptual and quantitative, regarding the coordinate trajectory and coordinate velocity of the null geodesic the light travels along. These errors, which appear to have remained unrecognized for at least 35 years, render the standard derivation inadequate and misleading as an archetype calculation. Here we identify the flaws in the existing derivation and provide, in full detail, a correct derivation of the response of a single-bounce Michelson interferometer to gravitational waves, following a procedure that will always yield correct results; compare it to the standard, but incorrect, derivation; show where the earlier mistakes were made; and identify the general conditions under which the standard derivation will yield correct results. By a fortuitous set of circumstances, not generally so, the final result is the same in the case of Minkowski background spacetime, synchronous coordinates, transverse-traceless gauge metric perturbations, and arm mirrors at coordinate rest.

  1. ISAS: interferometric stratospheric astrometry for solar system

    NASA Astrophysics Data System (ADS)

    Gai, M.; Fienga, A.; Lattanzi, M. G.; Riva, A.; Vecchiato, A.; Gallieni, D.; Chaillot, S.; Ligori, S.; Loreggia, D.

    2012-09-01

    The Interferometric Stratospheric Astrometry for Solar system (ISAS) project is designed for high precision astrometry on the brightest planets of the Solar System, with reference to many field stars, at the milli-arcsec (mas) level or better. The science goal is the improvement on our knowledge of the dynamics of the Solar System, complementing the Gaia observations of fainter objects. The technical goal is the validation of basic concepts for the proposed Gamma Astrometric Measurement Experiment (GAME) space mission, in particular, combination of Fizeau interferometry and coronagraphic techniques by means of pierced mirrors, intermediate angle dual field astrometry, smart focal plane management for increased dynamic range and pointing correction. We discuss the suitability of the stratospheric environment, close to space conditions, to the astrometric requirements. The instrument concept is a multiple field, multiple aperture Fizeau interferometer, observing simultaneously four fields, in order to improve on the available number of reference stars. Coronagraphic solutions are introduced to allow observation of internal planets (Mercury and Venus), as well as of external planets over a large fraction of their orbit, i.e. also close to conjunction with the Sun. We describe the science motivation, the proposed experiment profile and the expected performance.

  2. Interferometric smart material for measuring permanent deformations

    SciTech Connect

    Li, K.

    1996-05-01

    This paper has presented a novel interferometric smart material using closely spaced micro-indentations as sensors for recording permanent deformations. The information can be retrieved from the interference fringe patterns of laser light reflected and diffracted from the ISM indentations. Practically, the interference fringes are monitored with linear photodiode arrays in conjunction with a microcomputer based digital data acquisition system. The measurement can be conducted at any convenient time and needs not conflict with in-situ operations. Validity and accuracy of the method have been confirmed by the comparison with standard measurements. The ISM acts like a smart material to memorize permanent deformations. Different from the ISG and ISR real-time measuring techniques, the ISM measurement may be performed at any convenient time, and large deformations can be measured. The ISM method competes with other optical methods for its extremely compact sensors and applicability to production environments. It measures the indentation separations through analyzing the interference fringe patterns and has a better accuracy than a microscope. It is applicable to curved surfaces and notched regions in large structures.

  3. Interferometric Studies of Low-Mass Protostars

    NASA Astrophysics Data System (ADS)

    Jørgensen, Jes K.

    2011-12-01

    With the advances in high angular resolution (sub)millimeter observations of low-mass protostars, windows of opportunities are opening up for very detailed studies of the molecular structure of star forming regions on wide range of spatial scales. Deeply embedded protostars provide an important laboratory to study the chemistry of star formation - providing the link between dense regions in molecular clouds from which stars are formed, i.e., the initial conditions and the end product in terms of, e.g., disk and planet formation. High angular resolution observations at (sub)millimeter wavelengths provide an important tool for studying the chemical composition of such low-mass protostars. They for example constrain the spatial molecular abundance variations - and can thereby identify which species are useful tracers of different components of the protostars at different evolutionary stages. In this review I discuss the possibilities and limitations of using high angular resolution (sub)millimeter interferometric observations for studying the chemical evolution of low-mass protostars - with a particular keen eye toward near-future ALMA observations.

  4. Acoustic vs Interferometric Measurements of Lightning

    NASA Astrophysics Data System (ADS)

    Arechiga, R. O.; Erives, H.; Sonnenfeld, R. G.; Stanley, M. A.; Rison, W.; Thomas, R. J.; Edens, H. E.; Lapierre, J. L.; Stock, M.; Jensen, D.; Morris, K.

    2015-12-01

    During the summer of 2015 we acquired acoustic and RF data on severalflashes from thunderstorms over Fort Morgan CO. and Langmuir Laboratoryin the Magdalena mountains of central New Mexico. The acoustic arrayswere located at a distance of roughly 150 m from the interferometers.Lightning mapping array and slow antenna data were also obtained. Theacoustic arrays consist of arrays of five audio-range and six infrasoundmicrophones operating at 50 KHz and 1 KHz respectively. The lightninginterferometer at Fort Morgan CO. consists of three flat-plate, 13" diameterantennas at the vertices of an equilateral 50 m per side triangle. Theinterferometer at Langmuir Laboratory consists of three 13" dishes separatedby about 15 m. Both interferometers, operating at 180 Megasamples persecond, use the analysis software and digitizer hardware pioneered byStanley, Stock et al. The high data rate allows for excellent spatialresolution of high speed (and typically high current) processes such asK-changes, return strokes and dart-leaders. In previous studies, we haveshown the usefulness of acoustic recordings to locate thunder sources aswell as infrasound pulses from lightning. This work will present acomparison of Acoustic and Interferometric measurements from lightning,using some interesting flashes, including a positive cloud to ground,that occurred in these campaigns.

  5. Photonic crystal fiber interferometric vector bending sensor.

    PubMed

    Villatoro, Joel; Minkovich, Vladimir P; Zubia, Joseba

    2015-07-01

    A compact and highly sensitive interferometric bending sensor (inclinometer) capable of distinguishing the bending or inclination orientation is demonstrated. The device operates in reflection mode and consists of a short segment of photonic crystal fiber (PCF) inserted in conventional single-mode optical fiber (SMF). A microscopic collapsed zone in the PCF-SMF junction allows the excitation and recombination of core modes, hence, to build a mode interferometer. Bending on the device induces asymmetric refractive index changes in the PCF core as well as losses. As a result, the effective indices and intensities of the interfering modes are altered, which makes the interference pattern shift and shrink. The asymmetric index changes in the PCF make our device capable of distinguishing the bending orientation. The sensitivity of our sensor is up to 1225 pm/degree and it can be used to monitor small bending angles (±2°). We believe that the attributes of our sensor make it appealing in a number of applications. PMID:26125380

  6. Neutron Interferometric Search for Chameleon Dark Energy

    NASA Astrophysics Data System (ADS)

    Heacock, Benjamin; Index Collaboration

    2015-10-01

    The chameleon model for dark energy proposed by Khoury and Weltman is one of the only theories of dark energy which can be tested using laboratory experiments. The theory consists of a nonlinear scalar field whose range and intensity is a sensitive function of the local matter density, with the field becoming nonzero over ranges greater than 100 microns in only low density regions of space. We are searching for the induced phase shift due to a coupling of the chameleon to matter using neutron interferometry. By placing a two-chamber gas cell inside the neutron interferometer, we measure the neutron phase difference between low pressure (0.00025 torr) and higher pressure (0.1 torr) helium gas. The chameleon field is predicted to be suppressed only at the higher pressure, resulting in a phase from the chameleon on the low pressure side of the chamber. A double-difference technique is used to subtract the phase shift from the gas and chamber walls. We will discuss this experiment, ran at the NIST Center for Neutron Research, and present current constraints on the chameleon field. Interferometric Dark Energy eXperiment

  7. SARS Patients and Their Close Contacts

    MedlinePlus

    ... Fact Sheet for SARS Patients and Their Close Contacts Format: Select one PDF [256 KB] Recommend on ... that are not now known. What does "close contact" mean? In the context of SARS, close contact ...

  8. Fault Creep along the Southern San Andreas from Interferometric Synthetic Aperture Radar, Permanent Scatterers, and Stacking

    NASA Technical Reports Server (NTRS)

    Lyons, Suzanne; Sandwell, David

    2003-01-01

    Interferometric synthetic aperture radar (InSAR) provides a practical means of mapping creep along major strike-slip faults. The small amplitude of the creep signal (less than 10 mm/yr), combined with its short wavelength, makes it difficult to extract from long time span interferograms, especially in agricultural or heavily vegetated areas. We utilize two approaches to extract the fault creep signal from 37 ERS SAR images along the southem San Andreas Fault. First, amplitude stacking is utilized to identify permanent scatterers, which are then used to weight the interferogram prior to spatial filtering. This weighting improves correlation and also provides a mask for poorly correlated areas. Second, the unwrapped phase is stacked to reduce tropospheric and other short-wavelength noise. This combined processing enables us to recover the near-field (approximately 200 m) slip signal across the fault due to shallow creep. Displacement maps fiom 60 interferograms reveal a diffuse secular strain buildup, punctuated by localized interseismic creep of 4-6 mm/yr line of sight (LOS, 12-18 mm/yr horizontal). With the exception of Durmid Hill, this entire segment of the southern San Andreas experienced right-lateral triggered slip of up to 10 cm during the 3.5-year period spanning the 1992 Landers earthquake. The deformation change following the 1999 Hector Mine earthquake was much smaller (4 cm) and broader than for the Landers event. Profiles across the fault during the interseismic phase show peak-to-trough amplitude ranging from 15 to 25 mm/yr (horizontal component) and the minimum misfit models show a range of creeping/locking depth values that fit the data.

  9. Airborne data acquisition techniques

    SciTech Connect

    Arro, A.A.

    1980-01-01

    The introduction of standards on acceptable procedures for assessing building heat loss has created a dilemma for the contractor performing airborne thermographic surveys. These standards impose specifications on instrumentation, data acquisition, recording, interpretation, and presentation. Under the standard, the contractor has both the obligation of compliance and the requirement of offering his services at a reasonable price. This paper discusses the various aspects of data acquisition for airborne thermographic surveys and various techniques to reduce the costs of this operation. These techniques include the calculation of flight parameters for economical data