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Sample records for polarimetric interferometric sar

  1. 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.

  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. 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.

  4. 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.

  5. 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.

  6. An algorithm for segmenting polarimetric SAR imagery

    NASA Astrophysics Data System (ADS)

    Geaga, Jorge V.

    2015-05-01

    We have developed an algorithm for segmenting fully polarimetric single look TerraSAR-X, multilook SIR-C and 7 band Landsat 5 imagery using neural nets. The algorithm uses a feedforward neural net with one hidden layer to segment different surface classes. The weights are refined through an iterative filtering process characteristic of a relaxation process. Features selected from studies of fully polarimetric complex single look TerraSAR-X data and multilook SIR-C data are used as input to the net. The seven bands from Landsat 5 data are used as input for the Landsat neural net. The Cloude-Pottier incoherent decomposition is used to investigate the physical basis of the polarimetric SAR data segmentation. The segmentation of a SIR-C ocean surface scene into four classes is presented. This segmentation algorithm could be a very useful tool for investigating complex polarimetric SAR phenomena.

  7. 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.

  8. Unsupervised Segmentation Of Polarimetric SAR Data

    NASA Technical Reports Server (NTRS)

    Rignot, Eric J.; Dubois, Pascale; Van Zyl, Jakob; Kwok, Ronald; Chellappa, Rama

    1994-01-01

    Method of unsupervised segmentation of polarimetric synthetic-aperture-radar (SAR) image data into classes involves selection of classes on basis of multidimensional fuzzy clustering of logarithms of parameters of polarimetric covariance matrix. Data in each class represent parts of image wherein polarimetric SAR backscattering characteristics of terrain regarded as homogeneous. Desirable to have each class represent type of terrain, sea ice, or ocean surface distinguishable from other types via backscattering characteristics. Unsupervised classification does not require training areas, is nearly automated computerized process, and provides nonsubjective selection of image classes naturally well separated by radar.

  9. 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).

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. Measurement of Pancharatnam's phase by robust interferometric and polarimetric methods

    SciTech Connect

    Loredo, J. C.; Ortiz, O.; De Zela, F.; Weingaertner, R.

    2009-07-15

    We report on theoretical calculations and experimental observations of Pancharatnam's phase originating from arbitrary SU(2) transformations applied to polarization states of light. We have implemented polarimetric and interferometric methods, which allow us to cover the full Poincare sphere. As a distinctive feature, our interferometric array is robust against mechanical and thermal disturbances, showing that the polarimetric method is not inherently superior over the interferometric one, as previously assumed. Our strategy effectively amounts to feeding an interferometer with two copropagating beams that are orthogonally polarized with respect to each other. It can be applied to different types of standard arrays, such as a Michelson, a Sagnac, or a Mach-Zehnder interferometer. We exhibit the versatility of our arrangement by performing measurements of Pancharatnam's phases and fringe visibilities that closely fit the theoretical predictions. Our approach can be easily extended to deal with mixed states and to study decoherence effects.

  17. 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).

  18. 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.

  19. 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

  20. Unsupervised segmentation of polarimetric SAR data using the covariance matrix

    NASA Technical Reports Server (NTRS)

    Rignot, Eric; Chellappa, Rama; Dubois, Pascale; Kwok, Ronald; Van Zyl, Jacob

    1991-01-01

    An unsupervised selection of polarimetric features useful for the segmentation and analysis of polarimetric synthetic aperture radar (SAR) data is presented. The technique is based on multidimensional clustering of the parameters composing the polarimetric covariance matrix of the data. Clustering is performed on the logarithm of these quantities. Once the polarimetric cluster centers have been determined, segmentation of the polarimetric data into regions is performed using a maximum likelihood polarimetric classifier. Segmentation maps are further improved using a Markov random field to describe the statistics of the regions and computing the maximum of the product of the local conditional densities. Examples with real polarimetric SAR imagery are given to illustrate the potential of this method.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. Agricultural Performance Monitoring with Polarimetric SAR and Optical Imagery

    NASA Astrophysics Data System (ADS)

    Dhar, T.; Gray, D.; Menges, C.

    2009-04-01

    This paper presents the results from an experiment measuring yield using TerraSAR-X dual-polarimetric mode and precision agriculture machinery which records harvested amounts every few meters. The experimental field setup and data collection using TerraSAR-X are discussed and some preliminary results are shown.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. From Maxwell's Equations to Polarimetric SAR Images: A Simulation Approach

    PubMed Central

    Sant'Anna, Sidnei J. S.; da S. Lacava, J. C.; Fernandes, David

    2008-01-01

    A new electromagnetic approach for the simulation of polarimetric SAR images is proposed. It starts from Maxwell's equations, employs the spectral domain full-wave technique, the moment method, and the stationary phase method to compute the far electromagnetic fields scattered by multilayer structures. A multilayer structure is located at each selected position of a regular rectangular grid of coordinates, which defines the scene area under imaging. The grid is determined taking into account the elementary scatter size and SAR operational parameters, such as spatial resolution, pixel spacing, look angle and platform altitude. A two-dimensional separable “sinc” function to represent the SAR spread point function is also considered. Multifrequency sets of single-look polarimetric SAR images are generated, in L-, C- and X-bands and the images are evaluated using several measurements commonly employed in SAR data analysis. The evaluation shows that the proposed simulation process is working properly, since the obtained results are in accordance with those presented in the literature. Therefore, this new approach becomes suitable for carrying out theoretical and practical studies using polarimetric SAR images.

  13. 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.

  14. Polarimetric SAR Models for Oil Fields Monitoring in China Seas

    NASA Astrophysics Data System (ADS)

    Buono, A.; Nunziata, F.; Li, X.; Wei, Y.; Ding, X.

    2014-11-01

    In this study, physical-based models for polarimetric Synthetic Aperture Radar (SAR) oil fields monitoring are proposed. They all share a physical rationale relying on the different scattering mechanisms that characterize a free sea surface, an oil slick-covered sea surface, and a metallic target. In fact, sea surface scattering is well modeled by a Bragg-like behaviour, while a strong departure from Bragg scattering is in place when dealing with oil slicks and targets. Furthermore, the proposed polarimetric models aim at addressing simultaneously target and oil slick detection, providing useful extra information with respect to single-pol SAR data in order to approach oil discrimination and classification. Experiments undertaken over East and South China Sea from actual C-band RadarSAT-2 full-pol SAR data witness the soundness of the proposed rationale.

  15. Ensemble polarimetric SAR image classification based on contextual sparse representation

    NASA Astrophysics Data System (ADS)

    Zhang, Lamei; Wang, Xiao; Zou, Bin; Qiao, Zhijun

    2016-05-01

    Polarimetric SAR image interpretation has become one of the most interesting topics, in which the construction of the reasonable and effective technique of image classification is of key importance. Sparse representation represents the data using the most succinct sparse atoms of the over-complete dictionary and the advantages of sparse representation also have been confirmed in the field of PolSAR classification. However, it is not perfect, like the ordinary classifier, at different aspects. So ensemble learning is introduced to improve the issue, which makes a plurality of different learners training and obtained the integrated results by combining the individual learner to get more accurate and ideal learning results. Therefore, this paper presents a polarimetric SAR image classification method based on the ensemble learning of sparse representation to achieve the optimal classification.

  16. 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.

  17. 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.

  18. 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.

  19. Snow and glacier mapping with polarimetric SAR

    NASA Technical Reports Server (NTRS)

    Shi, Jiancheng; Dozier, Jeff; Rott, Helmut; Davis, Robert E.

    1991-01-01

    The objective of this study was to examine the capability of mapping snow and glaciers in alpine regions using synthetic aperture radar (SAR) imagery when topographic information is not available. The topographic effects on the received power for a resolution cell can be explained by the change in illumination area and incidence angle in a slant-rante representation of SAR imagery. The specific polarization signatures and phase difference between HH and VV components are relatively independent of the illuminated are, and the incidence angle has only a small effect on these parameters. They provide a suitable measurement data set for snow and glacier mapping in a high-relief area. The results show that the C-band images of the enhancement factor, the phase difference between HH and VV scattering components, and the normalized cross product of VV scattering elements provide the capability to discriminate among snow with different wetnesses, glaciers, and rocky regions.

  20. 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.

  1. 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.

  2. Accounting For Gains And Orientations In Polarimetric SAR

    NASA Technical Reports Server (NTRS)

    Freeman, Anthony

    1992-01-01

    Calibration method accounts for characteristics of real radar equipment invalidating standard 2 X 2 complex-amplitude R (receiving) and T (transmitting) matrices. Overall gain in each combination of transmitting and receiving channels assumed different even when only one transmitter and one receiver used. One characterizes departure of polarimetric Synthetic Aperture Radar (SAR) system from simple 2 X 2 model in terms of single parameter used to transform measurements into format compatible with simple 2 X 2 model. Data processed by applicable one of several prior methods based on simple model.

  3. 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.

  4. Multiscale Segmentation of Polarimetric SAR Image Based on Srm Superpixels

    NASA Astrophysics Data System (ADS)

    Lang, F.; Yang, J.; Wu, L.; Li, D.

    2016-06-01

    Multi-scale segmentation of remote sensing image is more systematic and more convenient for the object-oriented image analysis compared to single-scale segmentation. However, the existing pixel-based polarimetric SAR (PolSAR) image multi-scale segmentation algorithms are usually inefficient and impractical. In this paper, we proposed a superpixel-based binary partition tree (BPT) segmentation algorithm by combining the generalized statistical region merging (GSRM) algorithm and the BPT algorithm. First, superpixels are obtained by setting a maximum region number threshold to GSRM. Then, the region merging process of the BPT algorithm is implemented based on superpixels but not pixels. The proposed algorithm inherits the advantages of both GSRM and BPT. The operation efficiency is obviously improved compared to the pixel-based BPT segmentation. Experiments using the Lband ESAR image over the Oberpfaffenhofen test site proved the effectiveness of the proposed method.

  5. Dynamic and data-driven classification for polarimetric SAR images

    NASA Astrophysics Data System (ADS)

    Uhlmann, S.; Kiranyaz, S.; Ince, T.; Gabbouj, M.

    2011-11-01

    In this paper, we introduce dynamic and scalable Synthetic Aperture Radar (SAR) terrain classification based on the Collective Network of Binary Classifiers (CNBC). The CNBC framework is primarily adapted to maximize the SAR classification accuracy on dynamically varying databases where variations do occur in any time in terms of (new) images, classes, features and users' relevance feedback. Whenever a "change" occurs, the CNBC dynamically and "optimally" adapts itself to the change by means of its topology and the underlying evolutionary method MD PSO. Thanks to its "Divide and Conquer" type approach, the CNBC can also support varying and large set of (PolSAR) features among which it optimally selects, weighs and fuses the most discriminative ones for a particular class. Each SAR terrain class is discriminated by a dedicated Network of Binary Classifiers (NBC), which encapsulates a set of evolutionary Binary Classifiers (BCs) discriminating the class with a distinctive feature set. Moreover, with each incremental evolution session, new classes/features can be introduced which signals the CNBC to create new corresponding NBCs and BCs within to adapt and scale dynamically to the change. This can in turn be a significant advantage when the current CNBC is used to classify multiple SAR images with similar terrain classes since no or only minimal (incremental) evolution sessions are needed to adapt it to a new classification problem while using the previously acquired knowledge. We demonstrate our proposed classification approach over several medium and highresolution NASA/JPL AIRSAR images applying various polarimetric decompositions. We evaluate and compare the computational complexity and classification accuracy against static Neural Network classifiers. As CNBC classification accuracy can compete and even surpass them, the computational complexity of CNBC is significantly lower as the CNBC body supports high parallelization making it applicable to grid

  6. 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.

  7. Disaster debris estimation using high-resolution polarimetric stereo-SAR

    NASA Astrophysics Data System (ADS)

    Koyama, Christian N.; Gokon, Hideomi; Jimbo, Masaru; Koshimura, Shunichi; Sato, Motoyuki

    2016-10-01

    This paper addresses the problem of debris estimation which is one of the most important initial challenges in the wake of a disaster like the Great East Japan Earthquake and Tsunami. Reasonable estimates of the debris have to be made available to decision makers as quickly as possible. Current approaches to obtain this information are far from being optimal as they usually rely on manual interpretation of optical imagery. We have developed a novel approach for the estimation of tsunami debris pile heights and volumes for improved emergency response. The method is based on a stereo-synthetic aperture radar (stereo-SAR) approach for very high-resolution polarimetric SAR. An advanced gradient-based optical-flow estimation technique is applied for optimal image coregistration of the low-coherence non-interferometric data resulting from the illumination from opposite directions and in different polarizations. By applying model based decomposition of the coherency matrix, only the odd bounce scattering contributions are used to optimize echo time computation. The method exclusively considers the relative height differences from the top of the piles to their base to achieve a very fine resolution in height estimation. To define the base, a reference point on non-debris-covered ground surface is located adjacent to the debris pile targets by exploiting the polarimetric scattering information. The proposed technique is validated using in situ data of real tsunami debris taken on a temporary debris management site in the tsunami affected area near Sendai city, Japan. The estimated height error is smaller than 0.6 m RMSE. The good quality of derived pile heights allows for a voxel-based estimation of debris volumes with a RMSE of 1099 m3. Advantages of the proposed method are fast computation time, and robust height and volume estimation of debris piles without the need for pre-event data or auxiliary information like DEM, topographic maps or GCPs.

  8. 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.

  9. Performance of Polarimetric Processing Techniques using NAWC P-3 SAR Imagery

    NASA Technical Reports Server (NTRS)

    Teti, J. G., Jr.; Lee, R. R.-Y.; Verdi, J. S.; Boerner, W.-M.

    1996-01-01

    The use of synthetic aperture radar (SAR) polarimetric processing for enhancing the detection, classification, and/or identification of scene scattering features is described. This paper describes and compares the results obtained from applying the polarimetric techniques that have been developed and/or advanced by researchers at MIT Lincoln Laboratory, and basic polarimetric match filter (PMF) techniques that have been modified to treat distributed scatterers. The paper describes the individual polarimetric processing techniques and the formulation used fro their application to polarimetric imagery obtained from the NAWC P-3 SAR. In all cases, the polarimetric techniques have been applied to enhance the detection of distributed scatterers in clutter The emphasis arises from considering most complex scatterers of interest (either man made or natural) as distributed scatterers consisting of multiple scattering centers, and many modern polarimetric radar systems have the resolution performance to resolve the multiple scattering centers. Furthermore, the individual scattering centers of a distributed target can often exhibit different polarimetric scattering characteristics, and consequently do not respond favorably to polarimetric processing techniques derived for individual point scatterers. The treatment of distributed scatterers also includes concepts for tuning the polarimetric ensemble response of individual scattering centers.

  10. Assessing integration of intensity, polarimetric scattering, interferometric coherence and spatial texture metrics in PALSAR-derived land cover classification

    NASA Astrophysics Data System (ADS)

    Jin, Huiran; Mountrakis, Giorgos; Stehman, Stephen V.

    2014-12-01

    Synthetic aperture radar (SAR) is an important alternative to optical remote sensing due to its ability to acquire data regardless of weather conditions and day/night cycle. The Phased Array type L-band SAR (PALSAR) onboard the Advanced Land Observing Satellite (ALOS) provided new opportunities for vegetation and land cover mapping. Most previous studies employing PALSAR investigated the use of one or two feature types (e.g. intensity, coherence); however, little effort has been devoted to assessing the simultaneous integration of multiple types of features. In this study, we bridged this gap by evaluating the potential of using numerous metrics expressing four feature types: intensity, polarimetric scattering, interferometric coherence and spatial texture. Our case study was conducted in Central New York State, USA using multitemporal PALSAR imagery from 2010. The land cover classification implemented an ensemble learning algorithm, namely random forest. Accuracies of each classified map produced from different combinations of features were assessed on a pixel-by-pixel basis using validation data obtained from a stratified random sample. Among the different combinations of feature types evaluated, intensity was the most indispensable because intensity was included in all of the highest accuracy scenarios. However, relative to using only intensity metrics, combining all four feature types increased overall accuracy by 7%. Producer's and user's accuracies of the four vegetation classes improved considerably for the best performing combination of features when compared to classifications using only a single feature type.

  11. Oil Detection in a Coastal Marsh with Polarimetric SAR

    NASA Astrophysics Data System (ADS)

    Ramsey, E., III; Rangoonwala, A.; Suzuoki, Y.; Bannister, T.

    2011-09-01

    The NASA UAVSAR was deployed June 2010 to support Deep Water Horizon oil spill response activities specifically, oil detection and characterization, oil extent mapping in wetlands, coastal resource impact detection, and ecosystem recovery. The UAVSAR platform demonstrated enhanced capability to act rapidly and provide targeted mapping response. Our research focused on the effectiveness of high spatial resolution and fully polarimetric L-band Synthetic Aperture Radar (PolSAR) for mapping oil in wetlands, specifically within Barataria Bay in eastern coastal Louisiana. Barataria Bay contained a numerous site observations confirming spatially extensive shoreline oil impacts, multiple oil spill UAVSAR collections, and a near anniversary 2009 collection. PolSAR oil detection relied on decomposition and subsequent classifications of the single look complex (SLC) calibrated radar cross sections representing the complex elements of the scattering matrix. Initial analyses results found that shoreline marsh structural damage as well as oil on marsh plants and sediments without canopy structural damage were exhibited as anomalous features on post-spill SLC scenes but were not evident on the pre-spill SLC scene collected in 2009. Pre-spill and post-spill Freeman-Durden (FD) and Cloude-Pottier (CP) decompositions and the Wishart classifications seeded with the FD and CP classes (Wishart-FD) also highlighted these nearshore features as a change in dominate scatter from pre-spill to post-spill. SLC analyses also indicated penetration of oil ladened waters into interior marshes well past the immediate shorelines; however, these post-spill SLC analyses results could not be validated due to the lack of observational data and possible flooding in the pre-spill SLC scene.

  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. 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

  14. Segmentation of Polarimetric SAR Images Usig Wavelet Transformation and Texture Features

    NASA Astrophysics Data System (ADS)

    Rezaeian, A.; Homayouni, S.; Safari, A.

    2015-12-01

    Polarimetric Synthetic Aperture Radar (PolSAR) sensors can collect useful observations from earth's surfaces and phenomena for various remote sensing applications, such as land cover mapping, change and target detection. These data can be acquired without the limitations of weather conditions, sun illumination and dust particles. As result, SAR images, and in particular Polarimetric SAR (PolSAR) are powerful tools for various environmental applications. Unlike the optical images, SAR images suffer from the unavoidable speckle, which causes the segmentation of this data difficult. In this paper, we use the wavelet transformation for segmentation of PolSAR images. Our proposed method is based on the multi-resolution analysis of texture features is based on wavelet transformation. Here, we use the information of gray level value and the information of texture. First, we produce coherency or covariance matrices and then generate span image from them. In the next step of proposed method is texture feature extraction from sub-bands is generated from discrete wavelet transform (DWT). Finally, PolSAR image are segmented using clustering methods as fuzzy c-means (FCM) and k-means clustering. We have applied the proposed methodology to full polarimetric SAR images acquired by the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) L-band system, during July, in 2012 over an agricultural area in Winnipeg, Canada.

  15. Oil Detection in a Coastal Marsh with Polarimetric SAR

    NASA Astrophysics Data System (ADS)

    Ramsey, E.; Rangoonwala, A.; Suzuoki, Y.; Bannister, T.

    2011-12-01

    The NASA UAVSAR was deployed June 2010 to support Deep Water Horizon oil spill response activities expressly, oil characterization, oil detection in wetlands, and coastal resource impact detection and recovery. The UAVSAR demonstrated enhanced capability to act rapidly and provide targeted mapping responses. Our research focused on the effectiveness of high spatial resolution and fully polarimetric L-band SAR for mapping oil in wetlands, specifically within Barataria Bay in eastern coastal Louisiana (Fig.). The Bay contained numerous site observations confirming spatially extensive shoreline oil impacts, multiple UAVSAR collections, and a near anniversary 2009 collection. PolSAR oil detection relied on decomposition and subsequent classifications of the single look complex (SLC) scenes. Initial analyses results found that shoreline marsh structural damage accompanied by oil occurrence were exhibited as anomalous features on post-spill SLC flightlines but were not evident on the pre-spill SLC flightline collected in 2009. Pre-spill and post-spill Freeman-Durden (FD) and Cloude-Pottier (CP) decompositions and Wishart classifications seeded with the FD and CP classes (Wishart-FD, Wishart-CP)also highlighted these nearshore features as a change in dominate scatter. In addition, all decompositions and classifications identify a class of interior marshes within the central core of the study region that reproduce spatially extensive changes in backscatter exhibited on the pre-spill and post-spill SLC image comparisons and on all post-spill SLC images. The FD and CP decompositions revealed that the change is associated with a transform of dominant scatter from primarily surface or volume to double or even bounce. As a preponderance of evidence supports the penetration of oil-polluted waters into interior marshes, it is reasonable that marshes exhibiting different backscatter in the pre-spill and post-spill SLC renditions, identify interior marshes exposed to flushing

  16. 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.

  17. Random Forest and Rotation Forest for fully polarized SAR image classification using polarimetric and spatial features

    NASA Astrophysics Data System (ADS)

    Du, Peijun; Samat, Alim; Waske, Björn; Liu, Sicong; Li, Zhenhong

    2015-07-01

    Fully Polarimetric Synthetic Aperture Radar (PolSAR) has the advantages of all-weather, day and night observation and high resolution capabilities. The collected data are usually sorted in Sinclair matrix, coherence or covariance matrices which are directly related to physical properties of natural media and backscattering mechanism. Additional information related to the nature of scattering medium can be exploited through polarimetric decomposition theorems. Accordingly, PolSAR image classification gains increasing attentions from remote sensing communities in recent years. However, the above polarimetric measurements or parameters cannot provide sufficient information for accurate PolSAR image classification in some scenarios, e.g. in complex urban areas where different scattering mediums may exhibit similar PolSAR response due to couples of unavoidable reasons. Inspired by the complementarity between spectral and spatial features bringing remarkable improvements in optical image classification, the complementary information between polarimetric and spatial features may also contribute to PolSAR image classification. Therefore, the roles of textural features such as contrast, dissimilarity, homogeneity and local range, morphological profiles (MPs) in PolSAR image classification are investigated using two advanced ensemble learning (EL) classifiers: Random Forest and Rotation Forest. Supervised Wishart classifier and support vector machines (SVMs) are used as benchmark classifiers for the evaluation and comparison purposes. Experimental results with three Radarsat-2 images in quad polarization mode indicate that classification accuracies could be significantly increased by integrating spatial and polarimetric features using ensemble learning strategies. Rotation Forest can get better accuracy than SVM and Random Forest, in the meantime, Random Forest is much faster than Rotation Forest.

  18. Analysis of Scattering Components from Fully Polarimetric SAR Images for Improving Accuracies of Urban Density Estimation

    NASA Astrophysics Data System (ADS)

    Susaki, J.

    2016-06-01

    In this paper, we analyze probability density functions (PDFs) of scatterings derived from fully polarimetric synthetic aperture radar (SAR) images for improving the accuracies of estimated urban density. We have reported a method for estimating urban density that uses an index Tv+c obtained by normalizing the sum of volume and helix scatterings Pv+c. Validation results showed that estimated urban densities have a high correlation with building-to-land ratios (Kajimoto and Susaki, 2013b; Susaki et al., 2014). While the method is found to be effective for estimating urban density, it is not clear why Tv+c is more effective than indices derived from other scatterings, such as surface or double-bounce scatterings, observed in urban areas. In this research, we focus on PDFs of scatterings derived from fully polarimetric SAR images in terms of scattering normalization. First, we introduce a theoretical PDF that assumes that image pixels have scatterers showing random backscattering. We then generate PDFs of scatterings derived from observations of concrete blocks with different orientation angles, and from a satellite-based fully polarimetric SAR image. The analysis of the PDFs and the derived statistics reveals that the curves of the PDFs of Pv+c are the most similar to the normal distribution among all the scatterings derived from fully polarimetric SAR images. It was found that Tv+c works most effectively because of its similarity to the normal distribution.

  19. 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.

  20. Classification and monitoring of reed belts using dual-polarimetric TerraSAR-X time series

    NASA Astrophysics Data System (ADS)

    Heine, Iris; Jagdhuber, Thomas; Itzerott, Sibylle

    2016-04-01

    The shorelines of lakes in northeastern Germany are often covered by reed. These reed belts fulfill an important function as erosion protection, biotope for animals, carbon storage, and as cleaning filter for lake water. However, despite their importance for the limnic ecosystem, reed vegetation in northeastern Germany is not regularly monitored. In this research study we investigate the potential of synthetic aperture radar polarimetry (PolSAR) for seasonal monitoring of reed vegetation. SAR imagery enables sunlight- and (almost) weather-independent monitoring. Polarimetric decomposition techniques allow the physical characterization of the scattering scenario and the involved scatterers. Our study is based on 19 dual-polarimetric (HH/VV) TerraSAR-X images acquired between August 2014 and May 2015. We calculated different polarimetric indices comprising the HH and VV intensities, the dual-polarimetric coherency matrix with dominant and mean alpha scattering angles, entropy and anisotropy (normalized eigen-value difference) as well as combinations of entropy and anisotropy for the analysis of the scattering scenarios. The reed areas in the TerraSAR-X images were classified using a random forest algorithm and validated with high-resolution digital orthophotos. The time series analysis of the reed belts revealed significant seasonal changes in the double bounce sensitive parameters (intensity ratio HH/VV and intensity difference HH-VV, the co-polarimetric coherence phase and the dominant and mean alpha scattering angles). Additionally, the dual-polarimetric coherence (amplitude), anisotropy, entropy, and anisotropy-entropy-combinations showed seasonal changes of reed. In summer, the reed areas are characterized within the X-band SAR data by volume scattering, whereas in winter double-bounce scattering dominates. The volume scattering in summer is caused predominantly by reed leaves. In autumn, the leaves start to wither and fall off, so that in winter predominately

  1. 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.

  2. Statistical analysis of multilook polarimetric SAR data and terrain classification with adaptive distribution

    NASA Astrophysics Data System (ADS)

    Liu, Guoqing; Huang, ShunJi; Torre, Andrea; Rubertone, Franco S.

    1995-11-01

    This paper deals with analysis of statistical properties of multi-look processed polarimetric SAR data. Based on an assumption that the multi-look polarimetric measurement is a product between a Gamma-distributed texture variable and a Wishart-distributed polarimetric speckle variable, it is shown that the multi-look polarimetric measurement from a nonhomogeneous region obeys a generalized K-distribution. In order to validate this statistical model, two of its varied versions, multi-look intensity and amplitude K-distributions are particularly compared with histograms of the observed multi-look SAR data of three terrain types, ocean, forest-like and city regions, and with four empirical distribution models, Gaussian, log-normal, gamma and Weibull models. A qualitative relation between the degree of nonhomogeneity of a textured scene and the well-fitting statistical model is then empirically established. Finally, a classifier with adaptive distributions guided by the order parameter of the texture distribution estimated with local statistics is introduced to perform terrain classification, experimental results with both multi-look fully polarimetric data and multi-look single-channel intensity/amplitude data indicate its effectiveness.

  3. 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.

  4. Change detection of polarimetric SAR images based on the KummerU Distribution

    NASA Astrophysics Data System (ADS)

    Chen, Quan; Zou, Pengfei; Li, Zhen; Zhang, Ping

    2014-11-01

    In the society of PolSAR image segmentation, change detection and classification, the classical Wishart distribution has been used for a long time, but it especially suit to low-resolution SAR image, because in traditional sensors, only a small number of scatterers are present in each resolution cell. With the improving of SAR systems these years, the classical statistical models can therefore be reconsidered for high resolution and polarimetric information contained in the images acquired by these advanced systems. In this study, SAR image segmentation algorithm based on level-set method, added with distance regularized level-set evolution (DRLSE) is performed using Envisat/ASAR single-polarization data and Radarsat-2 polarimetric images, respectively. KummerU heterogeneous clutter model is used in the later to overcome the homogeneous hypothesis at high resolution cell. An enhanced distance regularized level-set evolution (DRLSE-E) is also applied in the later, to ensure accurate computation and stable level-set evolution. Finally, change detection based on four polarimetric Radarsat-2 time series images is carried out at Genhe area of Inner Mongolia Autonomous Region, NorthEastern of China, where a heavy flood disaster occurred during the summer of 2013, result shows the recommend segmentation method can detect the change of watershed effectively.

  5. A lithological classification method from fully polarimetric SAR data using Cloude-Pottier decomposition and SVM

    NASA Astrophysics Data System (ADS)

    Xie, Minghui; Zhang, Qi; Chen, Shengbo; Zha, Fengli

    2015-10-01

    This article puts forward a kind of lithological classification method to take advantage of the fully polarimetric SAR data for lithological classification by the combination of cloude-pottier decomposition and support vector machine(SVM). Cloude-pottier target decomposition method is used to extract three characteristic parameters from the fully polarimetric SAR data as polarization entropy(H), scattering Angle(α), and the anisotropic(A) in xingcheng region, Liaoning province. And these parameters are taken as a sample vector and selected as the radial basis function for the SVM classifier. Thus the lithological classification from the fully polarimetric SAR images is implemented for the study area. By the comparation to the geological map, the classification results can consist with the actual rock distribution very well, and the overall classification precision reaches 80.0871%. But wishart supervised classification precision reaches 73.3837% , It shows that the method is feasible and effective for full polarization SAR image classification. Compared with the conventional classification method, it greatly improves the accuracy of interpretation.

  6. Bayesian classification of polarimetric SAR images using adaptive a priori probabilities

    NASA Technical Reports Server (NTRS)

    Van Zyl, J. J.; Burnette, C. F.

    1992-01-01

    The problem of classifying earth terrain by observed polarimetric scattering properties is tackled with an iterative Bayesian scheme using a priori probabilities adaptively. The first classification is based on the use of fixed and not necessarily equal a priori probabilities, and successive iterations change the a priori probabilities adaptively. The approach is applied to an SAR image in which a single water body covers 10 percent of the image area. The classification accuracy for ocean, urban, vegetated, and total area increase, and the percentage of reclassified pixels decreases greatly as the iteration number increases. The iterative scheme is found to improve the a posteriori classification accuracy of maximum likelihood classifiers by iteratively using the local homogeneity in polarimetric SAR images. A few iterations can improve the classification accuracy significantly without sacrificing key high-frequency detail or edges in the image.

  7. 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.

  8. Multitemporal RADARSAT-2 polarimetric SAR data for urban land-cover mapping

    NASA Astrophysics Data System (ADS)

    Gao, Liang; Ban, Yifang

    2009-09-01

    The objective of this research is to evaluate the performance of multitemporal RADARSAT-2 polarimetric SAR data for urban land use/land-cover classification. Three dates of RADARSAT-2 polarimetric SAR data were acquired during the summer of 2008 over the rural-urban fringe of the Greater Toronto Area. The major land-cover types are residential areas, industry areas, bare land, golf courses, forest, and agricultural crops. The methodology used in this study follow the manner that first extracting the features and then carrying out the supervised classification taking the different feature combinations as an input. Support vectors machine is selected to be the classifier. SAR features including amplitude, intensity, long-term coherence, Freeman-Durden decomposition are extracted and compared by evaluating the classification abilities. Long-term coherence plays an important role in building discrimination in this study. The best classification results achieved by using the three dates HH, VH, HV amplitude layers and the coherence map. The overall accuracy is 82.3%. The results indicate that RADARSAT-2 polarimetric data has a potential to urban land-cover classification with the proper feature combinations.

  9. Multitemporal RADARSAT-2 polarimetric SAR data for urban land-cover mapping

    NASA Astrophysics Data System (ADS)

    Gao, Liang; Ban, Yifang

    2010-11-01

    The objective of this research is to evaluate the performance of multitemporal RADARSAT-2 polarimetric SAR data for urban land use/land-cover classification. Three dates of RADARSAT-2 polarimetric SAR data were acquired during the summer of 2008 over the rural-urban fringe of the Greater Toronto Area. The major land-cover types are residential areas, industry areas, bare land, golf courses, forest, and agricultural crops. The methodology used in this study follow the manner that first extracting the features and then carrying out the supervised classification taking the different feature combinations as an input. Support vectors machine is selected to be the classifier. SAR features including amplitude, intensity, long-term coherence, Freeman-Durden decomposition are extracted and compared by evaluating the classification abilities. Long-term coherence plays an important role in building discrimination in this study. The best classification results achieved by using the three dates HH, VH, HV amplitude layers and the coherence map. The overall accuracy is 82.3%. The results indicate that RADARSAT-2 polarimetric data has a potential to urban land-cover classification with the proper feature combinations.

  10. 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

  11. Kernel-machine-based classification in multi-polarimetric SAR data

    NASA Astrophysics Data System (ADS)

    Middelmann, Wolfgang; Ebert, Alfons; Thoennessen, Ulrich

    2005-05-01

    The focus of this paper is the classification of military vehicles in multi-polarimetric high-resolution spotlight SAR images in an ATR framework. Kernel machines as robust classification methods are the basis of our approach. A novel kernel machine the Relevance Vector Machine with integrated Generator (RVMG) controlling the trade-off between classification quality and computational effort is used. It combines the high classification quality of the Support Vector Machine by margin maximization and the low effort of the Relevance Vector Machine caused by the special statistical approach. Moreover multi-class classification capability is given by an efficient decision heuristic, an adaptive feature extraction based on Fourier coefficients allows the module to do real time execution, and a parameterized reject criterion is proposed in this paper. Investigations with a nine class data set from QinetiQ deal with fully polarimetric SAR data. The objective is to assess polarimetric features in combination with several kernel machines. Tests approve the high potential of RVMG. Moreover it is shown that polarimetric features can improve the classification quality for hard targets. Among these the simple energy based features prove more favorable than complex ones. Especially the two coplanar polarizations embody the essential information, but a better generalizability is caused by using all four channels. An important property of a classifier used in the ATR framework is the capability to reject objects not belonging to any of the trained classes. Therefore the QinetiQ data are divided into four training classes and five classes of confusion objects. The classification module with reject criterion is controlled by the reject parameter and the kernel parameter. Both parameters are varied to determine ROC curves related to different polarimetric features.

  12. Water-Body types identification in urban areas from radarsat-2 fully polarimetric SAR data

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

    This paper presents a novel method for supervised water-body extraction and water-body types identification from Radarsat-2 fully polarimetric (FP) synthetic aperture radar (SAR) data in complex urban areas. First, supervised water-body extraction using the Wishart classifier is performed, and the false alarms that are formed in built-up areas are removed using morphological processing methods and spatial contextual information. Then, the support vector machine (SVM), the classification and regression tree (CART), TreeBagger (TB), and random forest (RF) classifiers are introduced for water-body types (rivers, lakes, ponds) identification. In SAR images, certain other objects that are misclassified as water are also considered in water-body types identification. Several shape and polarimetric features of each candidate water-body are used for identification. Radarsat-2 PolSAR data that were acquired over Suzhou city and Dongguan city in China are used to validate the effectiveness of the proposed method, and the experimental results are evaluated at both the object and pixel levels. We compared the water-body types classification results using only shape features and the combination of shape and polarimetric features, the experimental results show that the polarimetric features can eliminate the misclassifications from certain other objects like roads to water areas, and the increasement of classification accuracy embodies at both the object and pixel levels. The experimental results show that the proposed methods can achieve satisfactory accuracies at the object level [89.4% (Suzhou), 95.53% (Dongguan)] and the pixel level [96.22% (Suzhou), 97.95% (Dongguan)] for water-body types classification, respectively.

  13. Advanced Unsupervised Classification Methods to Detect Anomalies on Earthen Levees Using Polarimetric SAR Imagery

    PubMed Central

    Marapareddy, Ramakalavathi; Aanstoos, James V.; Younan, Nicolas H.

    2016-01-01

    Fully polarimetric Synthetic Aperture Radar (polSAR) data analysis has wide applications for terrain and ground cover classification. The dynamics of surface and subsurface water events can lead to slope instability resulting in slough slides on earthen levees. Early detection of these anomalies by a remote sensing approach could save time versus direct assessment. We used L-band Synthetic Aperture Radar (SAR) to screen levees for anomalies. SAR technology, due to its high spatial resolution and soil penetration capability, is a good choice for identifying problematic areas on earthen levees. Using the parameters entropy (H), anisotropy (A), alpha (α), and eigenvalues (λ, λ1, λ2, and λ3), we implemented several unsupervised classification algorithms for the identification of anomalies on the levee. The classification techniques applied are H/α, H/A, A/α, Wishart H/α, Wishart H/A/α, and H/α/λ classification algorithms. In this work, the effectiveness of the algorithms was demonstrated using quad-polarimetric L-band SAR imagery from the NASA Jet Propulsion Laboratory’s (JPL’s) Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR). The study area is a section of the lower Mississippi River valley in the Southern USA, where earthen flood control levees are maintained by the US Army Corps of Engineers. PMID:27322270

  14. Advanced Unsupervised Classification Methods to Detect Anomalies on Earthen Levees Using Polarimetric SAR Imagery.

    PubMed

    Marapareddy, Ramakalavathi; Aanstoos, James V; Younan, Nicolas H

    2016-01-01

    Fully polarimetric Synthetic Aperture Radar (polSAR) data analysis has wide applications for terrain and ground cover classification. The dynamics of surface and subsurface water events can lead to slope instability resulting in slough slides on earthen levees. Early detection of these anomalies by a remote sensing approach could save time versus direct assessment. We used L-band Synthetic Aperture Radar (SAR) to screen levees for anomalies. SAR technology, due to its high spatial resolution and soil penetration capability, is a good choice for identifying problematic areas on earthen levees. Using the parameters entropy (H), anisotropy (A), alpha (α), and eigenvalues (λ, λ₁, λ₂, and λ₃), we implemented several unsupervised classification algorithms for the identification of anomalies on the levee. The classification techniques applied are H/α, H/A, A/α, Wishart H/α, Wishart H/A/α, and H/α/λ classification algorithms. In this work, the effectiveness of the algorithms was demonstrated using quad-polarimetric L-band SAR imagery from the NASA Jet Propulsion Laboratory's (JPL's) Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR). The study area is a section of the lower Mississippi River valley in the Southern USA, where earthen flood control levees are maintained by the US Army Corps of Engineers.

  15. Advanced Unsupervised Classification Methods to Detect Anomalies on Earthen Levees Using Polarimetric SAR Imagery.

    PubMed

    Marapareddy, Ramakalavathi; Aanstoos, James V; Younan, Nicolas H

    2016-01-01

    Fully polarimetric Synthetic Aperture Radar (polSAR) data analysis has wide applications for terrain and ground cover classification. The dynamics of surface and subsurface water events can lead to slope instability resulting in slough slides on earthen levees. Early detection of these anomalies by a remote sensing approach could save time versus direct assessment. We used L-band Synthetic Aperture Radar (SAR) to screen levees for anomalies. SAR technology, due to its high spatial resolution and soil penetration capability, is a good choice for identifying problematic areas on earthen levees. Using the parameters entropy (H), anisotropy (A), alpha (α), and eigenvalues (λ, λ₁, λ₂, and λ₃), we implemented several unsupervised classification algorithms for the identification of anomalies on the levee. The classification techniques applied are H/α, H/A, A/α, Wishart H/α, Wishart H/A/α, and H/α/λ classification algorithms. In this work, the effectiveness of the algorithms was demonstrated using quad-polarimetric L-band SAR imagery from the NASA Jet Propulsion Laboratory's (JPL's) Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR). The study area is a section of the lower Mississippi River valley in the Southern USA, where earthen flood control levees are maintained by the US Army Corps of Engineers. PMID:27322270

  16. 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.

  17. Random Forest Classification of Sediments on Exposed Intertidal Flats Using ALOS-2 Quad-Polarimetric SAR Data

    NASA Astrophysics Data System (ADS)

    Wang, W.; Yang, X.; Liu, G.; Zhou, H.; Ma, W.; Yu, Y.; Li, Z.

    2016-06-01

    Coastal zones are one of the world's most densely populated areas and it is necessary to propose an accurate, cost effective, frequent, and synoptic method of monitoring these complex ecosystems. However, misclassification of sediments on exposed intertidal flats restricts the development of coastal zones surveillance. With the advent of SAR (Synthetic Aperture Radar) satellites, polarimetric SAR satellite imagery plays an increasingly important role in monitoring changes in coastal wetland. This research investigated the necessity of combining SAR polarimetric features with optical data, and their contribution in accurately sediment classification. Three experimental groups were set to make assessment of the most appropriate descriptors. (i) Several SAR polarimetric descriptors were extracted from scattering matrix using Cloude-Pottier, Freeman-Durden and Yamaguchi methods; (ii) Optical remote sensing (RS) data with R, G and B channels formed the second feature combinations; (iii) The chosen SAR and optical RS indicators were both added into classifier. Classification was carried out using Random Forest (RF) classifiers and a general result mapping of intertidal flats was generated. Experiments were implemented using ALOS-2 L-band satellite imagery and GF-1 optical multi-spectral data acquired in the same period. The weights of descriptors were evaluated by VI (RF Variable Importance). Results suggested that optical data source has few advantages on sediment classification, and even reduce the effect of SAR indicators. Polarimetric SAR feature sets show great potentials in intertidal flats classification and are promising in classifying mud flats, sand flats, bare farmland and tidal water.

  18. A Review of the Applications of SAR Polarimetry and Polarimetric Interferometry - an ESA-funded study

    NASA Astrophysics Data System (ADS)

    Corr, D. G.; Cloude, S. R.; Ferro-Famil, L.; Hoekman, D. H.; Partington, K.; Pottier, E.; Rodrigues, A.

    2003-04-01

    This paper presents a literature review conducted under an ESA funded study entitled "Applications of SAR Polarimetry". This study was jointly conducted by QinetiQ, AELc, University of Rennes 1, SarVision and Vexcel UK. The overall study aim was to review, assess and validate the benefits of using polarimetry for land cover classification and sea ice classification. The potential of polarimetric interferometry for vegetation parameter retrieval was also assessed and demonstrated. A literature review on classification techniques for polarised SAR data was undertaken. The objective of this review was to choose the most promising techniques prior to their evaluation for land and sea ice applications. This paper presents the objectives, the key issues, the conclusions and recommendations of the review.

  19. Polarimetric SAR Data Gmm Classification Based on Improved Freeman Incoherent Decomposition

    NASA Astrophysics Data System (ADS)

    Rouabah, S.; Ouarzeddine, M.; Azmedroub, B.

    2016-06-01

    Due to the increasing volume of available SAR Data, powerful classification processings are needed to interpret the images. GMM (Gaussian Mixture Model) is widely used to model distributions. In most applications, GMM algorithm is directly applied on raw SAR data, its disadvantage is that forest and urban areas are classified with the same label and gives problems in interpretation. In this paper, a combination between the improved Freeman decomposition and GMM classification is proposed. The improved Freeman decomposition powers are used as feature vectors for GMM classification. The E-SAR polarimetric image acquired over Oberpfaffenhofen in Germany is used as data set. The result shows that the proposed combination can solve the standard GMM classification problem.

  20. Urban-area extraction from polarimetric SAR image using combination of target decomposition and orientation angle

    NASA Astrophysics Data System (ADS)

    Zou, Bin; Lu, Da; Wu, Zhilu; Qiao, Zhijun G.

    2016-05-01

    The results of model-based target decomposition are the main features used to discriminate urban and non-urban area in polarimetric synthetic aperture radar (PolSAR) application. Traditional urban-area extraction methods based on modelbased target decomposition usually misclassified ground-trunk structure as urban-area or misclassified rotated urbanarea as forest. This paper introduces another feature named orientation angle to improve urban-area extraction scheme for the accurate mapping in urban by PolSAR image. The proposed method takes randomness of orientation angle into account for restriction of urban area first and, subsequently, implements rotation angle to improve results that oriented urban areas are recognized as double-bounce objects from volume scattering. ESAR L-band PolSAR data of the Oberpfaffenhofen Test Site Area was used to validate the proposed algorithm.

  1. Estimating Forest Vertical Structure from Multialtitude, Fixed-Baseline Radar Interferometric and Polarimetric Data

    NASA Technical Reports Server (NTRS)

    Treuhaft, Robert N.; Law, Beverly E.; Siqueira, Paul R.

    2000-01-01

    Parameters describing the vertical structure of forests, for example tree height, height-to-base-of-live-crown, underlying topography, and leaf area density, bear on land-surface, biogeochemical, and climate modeling efforts. Single, fixed-baseline interferometric synthetic aperture radar (INSAR) normalized cross-correlations constitute two observations from which to estimate forest vertical structure parameters: Cross-correlation amplitude and phase. Multialtitude INSAR observations increase the effective number of baselines potentially enabling the estimation of a larger set of vertical-structure parameters. Polarimetry and polarimetric interferometry can further extend the observation set. This paper describes the first acquisition of multialtitude INSAR for the purpose of estimating the parameters describing a vegetated land surface. These data were collected over ponderosa pine in central Oregon near longitude and latitude -121 37 25 and 44 29 56. The JPL interferometric TOPSAR system was flown at the standard 8-km altitude, and also at 4-km and 2-km altitudes, in a race track. A reference line including the above coordinates was maintained at 35 deg for both the north-east heading and the return southwest heading, at all altitudes. In addition to the three altitudes for interferometry, one line was flown with full zero-baseline polarimetry at the 8-km altitude. A preliminary analysis of part of the data collected suggests that they are consistent with one of two physical models describing the vegetation: 1) a single-layer, randomly oriented forest volume with a very strong ground return or 2) a multilayered randomly oriented volume; a homogeneous, single-layer model with no ground return cannot account for the multialtitude correlation amplitudes. Below the inconsistency of the data with a single-layer model is followed by analysis scenarios which include either the ground or a layered structure. The ground returns suggested by this preliminary analysis seem

  2. Retrieval of the thickness of undeformed sea ice from C-band compact polarimetric SAR images

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Dierking, W.; Zhang, J.; Meng, J. M.; Lang, H. T.

    2015-10-01

    In this paper we introduce a parameter for the retrieval of the thickness of undeformed first-year sea ice that is specifically adapted to compact polarimetric SAR images. The parameter is denoted as "CP-Ratio". In model simulations we investigated the sensitivity of CP-Ratio to the dielectric constant, thickness, surface roughness, and incidence angle. From the results of the simulations we deduced optimal conditions for the thickness retrieval. On the basis of C-band CTLR SAR data, which were generated from Radarsat-2 quad-polarization images acquired jointly with helicopter-borne sea ice thickness measurements in the region of the Sea of Labrador, we tested empirical equations for thickness retrieval. An exponential fit between CP-Ratio and ice thickness provides the most reliable results. Based on a validation using other compact polarimetric SAR images from the same region we found a root mean square (rms) error of 8 cm and a maximum correlation coefficient of 0.92 for the retrieval procedure when applying it on level ice of 0.9 m mean thickness.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. Decomposition of Polarimetric SAR Images Based on Second- and Third-order Statics Analysis

    NASA Astrophysics Data System (ADS)

    Kojima, S.; Hensley, S.

    2012-12-01

    There are many papers concerning the research of the decomposition of polerimetric SAR imagery. Most of them are based on second-order statics analysis that Freeman and Durden [1] suggested for the reflection symmetry condition that implies that the co-polarization and cross-polarization correlations are close to zero. Since then a number of improvements and enhancements have been proposed to better understand the underlying backscattering mechanisms present in polarimetric SAR images. For example, Yamaguchi et al. [2] added the helix component into Freeman's model and developed a 4 component scattering model for the non-reflection symmetry condition. In addition, Arii et al. [3] developed an adaptive model-based decomposition method that could estimate both the mean orientation angle and a degree of randomness for the canopy scattering for each pixel in a SAR image without the reflection symmetry condition. This purpose of this research is to develop a new decomposition method based on second- and third-order statics analysis to estimate the surface, dihedral, volume and helix scattering components from polarimetric SAR images without the specific assumptions concerning the model for the volume scattering. In addition, we evaluate this method by using both simulation and real UAVSAR data and compare this method with other methods. We express the volume scattering component using the wire formula and formulate the relationship equation between backscattering echo and each component such as the surface, dihedral, volume and helix via linearization based on second- and third-order statics. In third-order statics, we calculate the correlation of the correlation coefficients for each polerimetric data and get one new relationship equation to estimate each polarization component such as HH, VV and VH for the volume. As a result, the equation for the helix component in this method is the same formula as one in Yamaguchi's method. However, the equation for the volume

  8. Using Polarimetric SAR Data to Infer Soil Moisture from Surfaces with Varying Subsurface Moisture Profiles

    NASA Technical Reports Server (NTRS)

    Khankhoje, Uday K.; van Zyl, Jakob; Kim, Yunjin; Cwik, Thomas

    2012-01-01

    A time-series approach is used to estimate the moisture content-based on polarimetric SAR data. It is found that under the assumption of constant soil moisture, empirically observed relationships between radar backscatter and moisture are only half as sensitive to moisture as compared to actual radar data. A numerical finite element method is used to calculate the radar backscatter for rough soils with arbitrarily varying soil moisture as a function of depth. Several instance of drying and wetting moisture profiles are considered and the radar backscatter is calculated in each case. Radar backscatter is found to crucially depend on the soil moisture variation in the top half wavelength of soil.

  9. 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.

  10. Structural classification of marshes with Polarimetric SAR highlighting the temporal mapping of marshes exposed to oil

    USGS Publications Warehouse

    Ramsey III, Elijah W.; Rangoonwala, Amina; Jones, Cathleen E.

    2015-01-01

    Empirical relationships between field-derived Leaf Area Index (LAI) and Leaf Angle Distribution (LAD) and polarimetric synthetic aperture radar (PolSAR) based biophysical indicators were created and applied to map S. alterniflora marsh canopy structure. PolSAR and field data were collected near concurrently in the summers of 2010, 2011, and 2012 in coastal marshes, and PolSAR data alone were acquired in 2009. Regression analyses showed that LAI correspondence with the PolSAR biophysical indicator variables equaled or exceeded those of vegetation water content (VWC) correspondences. In the final six regressor model, the ratio HV/VV explained 49% of the total 77% explained LAI variance, and the HH-VV coherence and phase information accounted for the remainder. HV/HH dominated the two regressor LAD relationship, and spatial heterogeneity and backscatter mechanism followed by coherence information dominated the final three regressor model that explained 74% of the LAD variance. Regression results applied to 2009 through 2012 PolSAR images showed substantial changes in marsh LAI and LAD. Although the direct cause was not substantiated, following a release of freshwater in response to the 2010 Deepwater Horizon oil spill, the fairly uniform interior marsh structure of 2009 was more vertical and dense shortly after the oil spill cessation. After 2010, marsh structure generally progressed back toward the 2009 uniformity; however, the trend was more disjointed in oil impact marshes.             

  11. Statistical modeling of targets and clutter in single-look non-polarimetric SAR imagery

    SciTech Connect

    Salazar, J.S.; Hush, D.R.; Koch, M.W.; Fogler, R.J.; Hostetler, L.D.

    1998-08-01

    This paper presents a Generalized Logistic (gLG) distribution as a unified model for Log-domain synthetic aperture Radar (SAR) data. This model stems from a special case of the G-distribution known as the G{sup 0}-distribution. The G-distribution arises from a multiplicative SAR model and has the classical K-distribution as another special case. The G{sup 0}-distribution, however, can model extremely heterogeneous clutter regions that the k-distribution cannot model. This flexibility is preserved in the unified gLG model, which is capable of modeling non-polarimetric SAR returns from clutter as well as man-made objects. Histograms of these two types of SAR returns have opposite skewness. The flexibility of the gLG model lies in its shape and shift parameters. The shape parameter describes the differing skewness between target and clutter data while the shift parameter compensates for movements in the mean as the shape parameter changes. A Maximum Likelihood (ML) estimate of the shape parameter gives an optimal measure of the skewness of the SAR data. This measure provides a basis for an optimal target detection algorithm.

  12. 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.

  13. Entropy-Alpha Classification Alternative for Polarimetric SAR Image

    NASA Astrophysics Data System (ADS)

    Praks, J.; Hallikainen, M.

    2003-04-01

    In this work we discuss SAR target entropy and alpha angle relations to other scattering covariance matrix characteristics and similarity invariants. It is shown that the sum of squared elements of the coherency matrix, normalized by its trace and determinant, has many common features with target entropy parameter. The first element of the matrix is very similar to alpha angle parameter describing scattering mechanism. Possibilities to use the sum of squared elements, determinant and first element of normalized coherency matrix for classification are studied. It appears that classification schemes very similar to entropy-alpha can be established. However, classification results differ slightly from those of entropy-alpha classification as here discussed two-parameter classifications depend on three variables, although parameters are in all cases the same. As an example, NASA/JPL AIRSAR L-Band image of the San Francisco Bay was classified with both proposed schemes and original entropy-alpha classification. The size of the used image was 224 x 256 pixels. The new algorithms classified 97% and 96%, respectively, of pixels to the same classes as entropy-alpha classification. The discussed similarity invariants are straightforward to calculate and they have been used to describe covariance matrix properties in statistics. Virtually are proposed classification algorithms equivalent with entropy-alpha classification because all three use the same amount of information from covariance matrix. However, proposed parameter pairs are much easier to calculate, as they do not require the computation of eigenvalues and eigenvectors.

  14. Non-Local Means Filter for Polarimetric SAR Speckle Reduction-Experiments Using Terrasar-X Data

    NASA Astrophysics Data System (ADS)

    Hu, J.; Guo, R.; Zhu, X.; Baier, G.; Wang, Y.

    2015-03-01

    The speckle is omnipresent in synthetic aperture radar (SAR) images as an intrinsic characteristic. However, it is unwanted in certain applications. Therefore, intelligent filters for speckle reduction are of great importance. It has been demonstrated in several literatures that the non-local means filter can reduce noise while preserving details. This paper discusses non-local means filter for polarimetric SAR (PolSAR) speckle reduction. The impact of different similarity approaches, weight kernels, and parameters in the filter were analysed. A data-driven adaptive weight kernel was proposed. Combined with different similarity measures, it is compared with existing algorithms, using fully polarimetric TerraSAR-X data acquired during the commissioning phase. The proposed approach has overall the best performance in terms of speckle reduction, detail preservation, and polarimetric information preservation. This study suggests the high potential of using the developed non- local means filer for speckle reduction of PolSAR data acquired by the next generation SAR missions, e.g. TanDEM-L and TerraSAR-X NG.

  15. Ocean Target Detection by the Cross-Polarized Channels of Fully Polarimetric SAR Data

    NASA Astrophysics Data System (ADS)

    Wang, Yunhua; Li, Huimin; He, Mingxia

    2014-11-01

    In SAR images, azimuth ambiguities are often mistaken as actual targets and cause false alarms. For actual targets, HV channel signals acquired by fully polarimetric SAR are approximately equal to VH channel in magnitude and phase, i.e., the reciprocity theorem applies, but shifted in phase about for the first-order azimuth ambiguities. Thus, the real part of (SʜvS*vʜ) can be defined as a new parameter for target detection at sea (hereafter it is called A₁₂ʀ). From the comparison with other parameters, we find that in A₁₂ʀ images, real target can be easily distinguished from the surrounding sea surface, and the first-order azimuth ambiguities of target are also removed completely.

  16. Analyzing C-band SAR polarimetric information for LAI and crop yield estimations

    NASA Astrophysics Data System (ADS)

    Molijn, Ramses A.; Iannini, Lorenzo; Mousivand, Ali; Hanssen, Ramon F.

    2014-10-01

    In this study, space remote sensing data and crop specific information from the ESA-led AgriSAR 2009 campaign are used for studying the profiles of C-band SAR backscatter signals and multispectral-based leaf area index (LAI) over the growth period of canola, pea and wheat. In addition, the correlations between radar backscatter parameters and the crop yields were analyzed, based on extracted statistics of temporal profiles. The results show that the HV backscatter and LAI are correlated differently before and after LAI peak. In addition, the coefficient of determination between peakrelated statistics from polarimetric indicator profiles and yield for pea fields can reach up to 0.68, and for canola and wheat up to 0.47 and 0.5, respectively. HV backscatter and coherence between HH and VV are most.

  17. Fitting a Two-Component Scattering Model to Polarimetric SAR Data from Forests

    NASA Technical Reports Server (NTRS)

    Freeman, Anthony

    2007-01-01

    Two simple scattering mechanisms are fitted to polarimetric synthetic aperture radar (SAR) observations of forests. The mechanisms are canopy scatter from a reciprocal medium with azimuthal symmetry and a ground scatter term that can represent double-bounce scatter from a pair of orthogonal surfaces with different dielectric constants or Bragg scatter from a moderately rough surface, which is seen through a layer of vertically oriented scatterers. The model is shown to represent the behavior of polarimetric backscatter from a tropical forest and two temperate forest sites by applying it to data from the National Aeronautic and Space Agency/Jet Propulsion Laboratory's Airborne SAR (AIRSAR) system. Scattering contributions from the two basic scattering mechanisms are estimated for clusters of pixels in polarimetric SAR images. The solution involves the estimation of four parameters from four separate equations. This model fit approach is justified as a simplification of more complicated scattering models, which require many inputs to solve the forward scattering problem. The model is used to develop an understanding of the ground-trunk double-bounce scattering that is present in the data, which is seen to vary considerably as a function of incidence angle. Two parameters in the model fit appear to exhibit sensitivity to vegetation canopy structure, which is worth further exploration. Results from the model fit for the ground scattering term are compared with estimates from a forward model and shown to be in good agreement. The behavior of the scattering from the ground-trunk interaction is consistent with the presence of a pseudo-Brewster angle effect for the air-trunk scattering interface. If the Brewster angle is known, it is possible to directly estimate the real part of the dielectric constant of the trunks, a key variable in forward modeling of backscatter from forests. It is also shown how, with a priori knowledge of the forest height, an estimate for the

  18. 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.

  19. Role of Polarimetric SAR data for discrimination/biophysical parameters of crops based on canopy architecture

    NASA Astrophysics Data System (ADS)

    Haldar, D.; Chakraborty, M.; Manjunath, K. R.; Parihar, J. S.

    2014-11-01

    Synthetic Aperture Radar (SAR) sensors have great potential for a wide range of agricultural applications, owing to their capability of all-weather observation. It is particularly useful in tropical regions in Asia where most of the crops are grown in rainy season. The use of SAR images for the assessment of rice-planted area is in operational stage in Asian countries owing to its characteristic temporal signature however, applications of SAR images for the estimation of biophysical plant variables are challenging, especially for crop scattering and discrimination in case of other tropical crops. Canopy geometry and architecture mainly govern the interaction of microwave signal with the vegetation. In this study evaluation of C-band SAR data at different polarization combinations in linear as well as circular polarimetric imaging modes for rabi crops and other associated landuse has been attempted. Also understanding the scattering response of various crops based on canopy architecture was attempted. The scattering parameters were found to vary for planofiles and erectophiles, partitioning of scattering and absorption were determined.

  20. The polarimetric entropy classification of SAR based on the clustering and signal noise ration

    NASA Astrophysics Data System (ADS)

    Shi, Lei; Yang, Jie; Lang, Fengkai

    2009-10-01

    Usually, Wishart H/α/A classification is an effective unsupervised classification method. However, the anisotropy parameter (A) is an unstable factor in the low signal noise ration (SNR) areas; at the same time, many clusters are useless to manually recognize. In order to avoid too many clusters to affect the manual recognition and the convergence of iteration and aiming at the drawback of the Wishart classification, in this paper, an enhancive unsupervised Wishart classification scheme for POLSAR data sets is introduced. The anisotropy parameter A is used to subdivide the target after H/α classification, this parameter has the ability to subdivide the homogeneity area in high SNR condition which can not be classified by using H/α. It is very useful to enhance the adaptability in difficult areas. Yet, the target polarimetric decomposition is affected by SNR before the classification; thus, the local homogeneity area's SNR evaluation is necessary. After using the direction of the edge detection template to examine the direction of POL-SAR images, the results can be processed to estimate SNR. The SNR could turn to a powerful tool to guide H/α/A classification. This scheme is able to correct the mistake judging of using A parameter such as eliminating much insignificant spot on the road and urban aggregation, even having a good performance in the complex forest. To convenience the manual recognition, an agglomerative clustering algorithm basing on the method of deviation-class is used to consolidate some clusters which are similar in 3by3 polarimetric coherency matrix. This classification scheme is applied to full polarimetric L band SAR image of Foulum area, Denmark.

  1. 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.

  2. 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

  3. Use of Radarsat-2 Polarimetric SAR Images for Fuel Moisture Mapping in Alaska Boreal Forests and South Africa Savannahs

    NASA Astrophysics Data System (ADS)

    Leblon, B.; Bourgeau-Chavez, L. L.; Kong, M.; Buckley, J. R.; Mathieu, R. M.; Charbonneau, F.; Gross, C. P.; Naidoo, L.

    2014-12-01

    The study reported a comparison between two Radarsat-2 polarimetric SAR (polSAR) images from extreme dry versus wet conditions are compared in an effort to determine the value of using polarimetric SAR data for estimating fuel moisture over South Africa savannahs and Alaska boreal forests. The savannahs study area is located into the Kruger National Park area and has 36 sites of lowveld savannas from bare overgrazed sites to medium-dense savannahs. The boreal forest study area has a chronosequence of black spruce ecosystems (recent burns, shrub-dominated regenerating forests , open canopied forests, moderately dense forest cover). Both study areas have a fairly level topography suitable for radar studies. The polSAR images were acquired using the same beam mode (FQ5 (23-25° incidence angle over the boreal sites, FQ15 (34.47-36.05° incidence angle) over the savannahs sites). Over each study area, soil moisture and vegetation structural data were measured in situ concurrently to the acquisition of the SAR imagery. The polSAR images were filtered for speckle noise using a Lee sigma filter and several polarimetric products were computed, such as those directly derived from the images (single linear and polairzed backscatters, polarimetric discriminators) and from target decompositions (Freeman-Durden, new van Zyl, Cloude-Pottier). Because most of these variables have a different unit, a normalized difference (in %) for each variable was calculated using the median values of the dry and wet dates for easier comparison of variable changes between the dates. Over both study areas, the normalized difference between wet and dry conditions was lower when higher tree canopy occurs. Results show utility of C-HH and C-RR polarized backscatters. Several polarimetric discriminators (dmin, Pr max, Pr min, Smax, Smin) were also significantly affected by the soil wetness. The Freeman Durden and van Zyl decomposition parameters outperformed the Cloude-Pottier decomposition

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Unsupervised polarimetric SAR urban area classification based on model-based decomposition with cross scattering

    NASA Astrophysics Data System (ADS)

    Xiang, Deliang; Tang, Tao; Ban, Yifang; Su, Yi; Kuang, Gangyao

    2016-06-01

    Since it has been validated that cross-polarized scattering (HV) is caused not only by vegetation but also by rotated dihedrals, in this study, we use rotated dihedral corner reflectors to form a cross scattering matrix and propose an extended four-component model-based decomposition method for PolSAR data over urban areas. Unlike other urban area decomposition techniques which need to discriminate the urban and natural areas before decomposition, this proposed method is applied on PolSAR image directly. The building orientation angle is considered in this scattering matrix, making it flexible and adaptive in the decomposition. Therefore, we can separate cross scattering of urban areas from the overall HV component. Further, the cross and helix scattering components are also compared. Then, using these decomposed scattering powers, the buildings and natural areas can be easily discriminated from each other using a simple unsupervised K-means classifier. Moreover, buildings aligned and not aligned along the radar flight direction can be also distinguished clearly. Spaceborne RADARSAT-2 and airborne AIRSAR full polarimetric SAR data are used to validate the performance of our proposed method. The cross scattering power of oriented buildings is generated, leading to a better decomposition result for urban areas with respect to other state-of-the-art urban decomposition techniques. The decomposed scattering powers significantly improve the classification accuracy for urban areas.

  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. 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.

  11. 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.

  12. 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.

  13. Clustering of Multi-Temporal Fully Polarimetric L-Band SAR Data for Agricultural Land Cover Mapping

    NASA Astrophysics Data System (ADS)

    Tamiminia, H.; Homayouni, S.; Safari, A.

    2015-12-01

    Recently, the unique capabilities of Polarimetric Synthetic Aperture Radar (PolSAR) sensors make them an important and efficient tool for natural resources and environmental applications, such as land cover and crop classification. The aim of this paper is to classify multi-temporal full polarimetric SAR data using kernel-based fuzzy C-means clustering method, over an agricultural region. This method starts with transforming input data into the higher dimensional space using kernel functions and then clustering them in the feature space. Feature space, due to its inherent properties, has the ability to take in account the nonlinear and complex nature of polarimetric data. Several SAR polarimetric features extracted using target decomposition algorithms. Features from Cloude-Pottier, Freeman-Durden and Yamaguchi algorithms used as inputs for the clustering. This method was applied to multi-temporal UAVSAR L-band images acquired over an agricultural area near Winnipeg, Canada, during June and July in 2012. The results demonstrate the efficiency of this approach with respect to the classical methods. In addition, using multi-temporal data in the clustering process helped to investigate the phenological cycle of plants and significantly improved the performance of agricultural land cover mapping.

  14. The Touzi Decomposition for Wetland Classification Using Polarimetric C-Band SAR

    NASA Astrophysics Data System (ADS)

    Touzi, E.; Deschamps, A.; Demers, A. M.; Rother, G.

    2009-04-01

    The Touzi decomposition [1] is investigated for wetland characterization. Like the Cloude α scattering type, the magnitude αs of the symmetric scattering is not effective for vegetation type discrimination. The phase Φαs of the symmetric scattering type has to be used for enhanced characterization of wetland vegetation species. A new tool is introduced for assessment of the scattering type phase coherence, and the phase of the dominant scattering type is shown to be very promising for wetland target classifica- tion. The unique information provided by Φαs for enhanced wetland class discrimination is demonstrated using Convair- 580 polarimetric C-band SAR data collected over the Mer Bleue wetland in the East of Ottawa, Canada. The use of Φαs makes possible the discrimination of shrub bog from sedges fen, and permits even the discrimination between conifer dominated treed bog from upland deciduous forest under leafy conditions.

  15. Three-Component Decomposition Based on Stokes Vector for Compact Polarimetric SAR

    PubMed Central

    Wang, Hanning; Zhou, Zhimin; Turnbull, John; Song, Qian; Qi, Feng

    2015-01-01

    In this paper, a three-component decomposition algorithm is proposed for processing compact polarimetric SAR images. By using the correspondence between the covariance matrix and the Stokes vector, three-component scattering models for CTLR and DCP modes are established. The explicit expression of decomposition results is then derived by setting the contribution of volume scattering as a free parameter. The degree of depolarization is taken as the upper bound of the free parameter, for the constraint that the weighting factor of each scattering component should be nonnegative. Several methods are investigated to estimate the free parameter suitable for decomposition. The feasibility of this algorithm is validated by AIRSAR data over San Francisco and RADARSAT-2 data over Flevoland. PMID:26393610

  16. 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

  17. A Combined Use of Decomposition and Texture for Terrain Classification of Fully Polarimetric SAR Images

    NASA Astrophysics Data System (ADS)

    Rodionova, N. V.

    2007-03-01

    This p aper presents two-stag e unsupervised terrain classification of fully polarimetr ic SA R data using Freeman and Durden decomposition based on three simp le scattering mechanisms: surface, volume and double bounce (first step), and textur al features (uncorrelated uniformity , contr ast, inv erse mo men t and entropy) obtained from grey lev el co-occurrence matr ices (GLCM) (second step). Textural f eatures ar e defined in moving w indow 5x5 pixels w ith N=32 (N - number of grey lev els) . This algorith m preserves th e purity of domin ant polarimetric scattering properties and defines textural features in each scatter ing category. It is shown better object discrimin ation after app lying textur e w ith in fix ed scattering category. Speckle r eduction is one of th e main mo ments in imag e interpr etation improvement because of its great influen ce on textur e. Results from unfiltered and Lee filtered polar imetr ic SAR imag es show that the v alues of contrast and en tropy decr ease and th e values of uniformity and inverse moment increase with speckle reduction, that's tru e for all polarizations (HH, VV, HV). Th e d iscr imination b etw een objects increases after speckle f ilter ing. Polar ization influen ce on textur e features is def ined by calculating th e features in SAR images w ith HH , VV and HV polarizations before and after speck le filter ing, and then creating RG B images. It is shown mor e polarization inf luence on textur e features (uniformity , inverse mo ment and entropy) before filtering and less influen ce - after speck le f iltering. I t's not true for contrast wher e polar ization influen ce is not ch anged practically w ith filtering. SIR-C/X-SA R SLC L-band imag es of Moscow r egion are used for illustr ation.

  18. Detection of aircraft crash sites from space using fully polarimetric SIR-C SAR imagery for search and rescue applications

    NASA Astrophysics Data System (ADS)

    Jackson, Christopher R.; Rais, Houra

    1999-08-01

    The Beaconless Search & Rescue Program at NASA Goddard Space Flight Center (GSFC) has been working to solve the technological challenges associated with detecting small aircraft crash sites using synthetic aperture radar (SAR) imagery. One area of work has focused on the use of fully polarimetric imagery to both improve image quality and distinguish the crash sites from the natural background. Data from aircraft based SARs have been used for development but since a SAR satellite deployment is one possible option for a practical Search and Rescue system, the work is being extended to satellite SAR imagery. This paper presents the results of processing Shuttle Imaging Radar-C (SIR-C) data collected over an aircraft crash site near Wadesboro, North Carolina through the target detection software developed at GSFC. The results demonstrate the ability to achieve crash site detection using SAR data collected from Earth orbit.

  19. 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.

  20. 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.

  1. 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.

  2. Creep rate estimation along the Hayward fault using polarimetric SAR interferometry

    NASA Astrophysics Data System (ADS)

    Alipour, S.; Tiampo, K. F.; Samsonov, S. V.; Gonzalez, P. J.

    2011-12-01

    The Hayward fault running through eastern San Francisco Bay represents a significant seismic hazard in northern California. Surface geodetic measurements, including those from creepmeters and continuous GPS, manifest aseismic creep equivalent to 4-9 mm/yr along this fault. Comparison with the long-term slip rate estimates of ~9 mm/yr suggest that up to several meters of slip potential has accumulated since the last large event, making the Hayward fault now capable of M>6.5 earthquakes. Here we apply polarimetric Synthetic Aperture Radar interferometry (PolInSAR) on quad-pol Radarsat-2 images acquired from 2008 to 2011 in order to map the surface creep along the northern thirty km of the Hayward fault. In addition to quantifying aseismic creep across the fault, the polInSAR data depict another sharp discontinuity in range change to the northeast of the fault, an indication of ongoing creep along a second fault in that region. Comparison of the recent creep rate estimates along the Hayward fault with the previous measurements proves that there is consistency in the right-lateral aseismic slip. However, vertical movements corresponding to landslides on slopes near Berkeley display a lower mean velocity for the period 2008-2011 than 1992-2000. Modeling of the slip distribution using the polInSAR data in conjunction with creepmeter and GPS data provides additional insights into the depth of the creeping zone and the locking segments of the fault, an indicator of the extent of any probable rupture and the magnitude of the potential future event.

  3. Modeling Surface Roughness to Estimate Surface Moisture Using Radarsat-2 Quad Polarimetric SAR Data

    NASA Astrophysics Data System (ADS)

    Nurtyawan, R.; Saepuloh, A.; Budiharto, A.; Wikantika, K.

    2016-08-01

    Microwave backscattering from the earth's surface depends on several parameters such as surface roughness and dielectric constant of surface materials. The two parameters related to water content and porosity are crucial for estimating soil moisture. The soil moisture is an important parameter for ecological study and also a factor to maintain energy balance of land surface and atmosphere. Direct roughness measurements to a large area require extra time and cost. Heterogeneity roughness scale for some applications such as hydrology, climate, and ecology is a problem which could lead to inaccuracies of modeling. In this study, we modeled surface roughness using Radasat-2 quad Polarimetric Synthetic Aperture Radar (PolSAR) data. The statistical approaches to field roughness measurements were used to generate an appropriate roughness model. This modeling uses a physical SAR approach to predicts radar backscattering coefficient in the parameter of radar configuration (wavelength, polarization, and incidence angle) and soil parameters (surface roughness and dielectric constant). Surface roughness value is calculated using a modified Campbell and Shepard model in 1996. The modification was applied by incorporating the backscattering coefficient (σ°) of quad polarization HH, HV and VV. To obtain empirical surface roughness model from SAR backscattering intensity, we used forty-five sample points from field roughness measurements. We selected paddy field in Indramayu district, West Java, Indonesia as the study area. This area was selected due to intensive decreasing of rice productivity in the Northern Coast region of West Java. Third degree polynomial is the most suitable data fitting with coefficient of determination R2 and RMSE are about 0.82 and 1.18 cm, respectively. Therefore, this model is used as basis to generate the map of surface roughness.

  4. Study of scattering characteristics of lunar equatorial region using Chandrayaan-1 Mini-SAR polarimetric data

    NASA Astrophysics Data System (ADS)

    Saran, Sriram; Das, Anup; Mohan, Shiv; Chakraborty, Manab

    2012-10-01

    The miniaturized synthetic aperture radar Mini-SAR onboard Indian Chandrayaan-1 mission was the first ever lunar orbiting SAR that acquired several data strips covering a wide variety of geological units over lunar equatorial and low latitude regions, some of which were not studied earlier at radar wavelengths. The Mini-SAR observations, complemented by high resolution optical imagery and higher incidence angle radar datasets, were effectively used to create a catalog of SAR backscatter properties of various lunar geological features. The radar backscatter along with the parameters circular polarization ratio (CPR), relative phase (δ) and m (the degree of polarization)-chi (the Poincare ellipticity) decomposition technique were used to study the scattering mechanisms, surface/sub-surface roughness and regional topography of some of the craters and their ejecta fields. The study revealed that the Taylor and Descartes craters in the lunar highlands region were characterized by high backscatter and low CPR values, while the Maunder and Kopff craters in the Mare Orientale basin were characterized by relatively low backscatter and elevated CPR values. The fresh crater Jackson and its ejecta blankets on the lunar far-side showed very high backscatter along with elevated CPR values due to the presence of abundant wavelength-scale scatterers. The radar dark Pyroclastic Orientale ring deposits showed both low backscatter and low CPR values, as reported by previous radar observations of pyroclastic deposits. The elevated CPR values corresponding to the interior and exterior of Santos Dumont crater could be attributed to rough crater walls and regional topography, respectively. Finally, attempt was made to bring out the differences in the origin of two similar-sized craters Taylor and Kopff, with the help of SAR polarimetric parameters. Differences in the CPR values of Mare and highland craters were attributed to the sensitivity of CPR to the ilmenite content and presence of

  5. Oil detection in a coastal marsh with polarimetric Synthetic Aperture Radar (SAR)

    USGS Publications Warehouse

    Ramsey, Elijah W.; Rangoonwala, Amina; Suzuoki, Yukihiro; Jones, Cathleen E.

    2011-01-01

    The National Aeronautics and Space Administration's airborne Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) was deployed in June 2010 in response to the Deepwater Horizon oil spill in the Gulf of Mexico. UAVSAR is a fully polarimetric L-band Synthetic Aperture Radar (SAR) sensor for obtaining data at high spatial resolutions. Starting a month prior to the UAVSAR collections, visual observations confirmed oil impacts along shorelines within northeastern Barataria Bay waters in eastern coastal Louisiana. UAVSAR data along several flight lines over Barataria Bay were collected on 23 June 2010, including the repeat flight line for which data were collected in June 2009. Our analysis of calibrated single-look complex data for these flight lines shows that structural damage of shoreline marsh accompanied by oil occurrence manifested as anomalous features not evident in pre-spill data. Freeman-Durden (FD) and Cloude-Pottier (CP) decompositions of the polarimetric data and Wishart classifications seeded with the FD and CP classes also highlighted these nearshore features as a change in dominant scattering mechanism. All decompositions and classifications also identify a class of interior marshes that reproduce the spatially extensive changes in backscatter indicated by the pre- and post-spill comparison of multi-polarization radar backscatter data. FD and CP decompositions reveal that those changes indicate a transform of dominant scatter from primarily surface or volumetric to double or even bounce. Given supportive evidence that oil-polluted waters penetrated into the interior marshes, it is reasonable that these backscatter changes correspond with oil exposure; however, multiple factors prevent unambiguous determination of whether UAVSAR detected oil in interior marshes.

  6. Phase of Target Scattering for Wetland Characterization using Polarimetric C-Band SAR

    SciTech Connect

    Touzi, R; Deschamps, Mireille C; Rother, Gernot

    2009-09-01

    Wetlands continue to be under threat, and there is a major need for mapping and monitoring wetlands for better management and protection of these sensitive areas. Only a few studies have been published on wetland characterization using polarimetric synthetic aperture radars (SARs). The most successful results have been obtained using the phase difference between HH and VV polarizations, phi{sub HH} - phi{sub VV}, which has shown promise for separating flooded wetland classes. Recently, we have introduced a new decomposition, the Touzi decomposition, which describes target scattering type in terms of a complex entity, the symmetric scattering type. Huynen's target helicity is used to assess the symmetric nature of target scattering. In this paper, the new complex-scattering-type parameters, the magnitude alphas and phase Phi{sub alpha} s, are investigated for wetland characterization. The use of the dominant-scattering-type phase Phi{sub alpha} s makes it possible to discriminate shrub bogs from poor (sedge or shrub) fens. These two classes cannot be separated using phi{sub HH} - phi{sub VV}, or the radiometric scattering information provided by alphas, the Cloude alpha, the entropy H, and the multipolarization HH-HV-VV channels. phi{sub alpha} s, which cannot detect deep (45 cm below the peat surface) water flow in a bog, is more sensitive to the shallower (10-20-cm) fen beneath water, and this makes possible the separation of poor fens from shrub bogs. Phi{sub alpha} s also permits the discrimination of conifer-dominated treed bog from upland deciduous forest under leafy conditions. Target helicity information is exploited to introduce a new parameter, the target asymmetry. The latter is shown very promising for detection of forest changes between leafy and no-leaf conditions. The analysis of low-entropy marsh scattering showed that both the scattering-type magnitude and phas- - e alphas and Phi{sub alpha} s, respectively, as well as the maximum polarization

  7. 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

  8. Polarimetric target detection techniques and results from the Goddard Space Flight Center Search and Rescue Synthetic Aperature Radar (SAR2) program

    NASA Astrophysics Data System (ADS)

    Jackson, Christopher R.; Rais, Houra; Mansfield, Arthur W.

    1998-09-01

    Over the SAR2 programs seven year history, a great deal of original research has been done in the area of automatic target detection for identifying aircraft crash site locations in synthetic aperture radar (SAR) imagery. The efforts have focused on using the polarimetric properties of the radar signal to both improve image quality and distinguish the crash sits from the natural background. A crash sites polarimetric 'signature' is expected to be present even in the absence of a strong intensity return. Several of these advanced methods are summarized and a methodology for their application described. Several detection results are presented using data from the NASA/JPL AirSAR.

  9. 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.

  10. Unsupervised classification algorithm based on EM method for polarimetric SAR images

    NASA Astrophysics Data System (ADS)

    Fernández-Michelli, J. I.; Hurtado, M.; Areta, J. A.; Muravchik, C. H.

    2016-07-01

    In this work we develop an iterative classification algorithm using complex Gaussian mixture models for the polarimetric complex SAR data. It is a non supervised algorithm which does not require training data or an initial set of classes. Additionally, it determines the model order from data, which allows representing data structure with minimum complexity. The algorithm consists of four steps: initialization, model selection, refinement and smoothing. After a simple initialization stage, the EM algorithm is iteratively applied in the model selection step to compute the model order and an initial classification for the refinement step. The refinement step uses Classification EM (CEM) to reach the final classification and the smoothing stage improves the results by means of non-linear filtering. The algorithm is applied to both simulated and real Single Look Complex data of the EMISAR mission and compared with the Wishart classification method. We use confusion matrix and kappa statistic to make the comparison for simulated data whose ground-truth is known. We apply Davies-Bouldin index to compare both classifications for real data. The results obtained for both types of data validate our algorithm and show that its performance is comparable to Wishart's in terms of classification quality.

  11. 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.

  12. An Unsupervised Change Detection Based on Test Statistic and KI from Multi-Temporal and Full Polarimetric SAR Images

    NASA Astrophysics Data System (ADS)

    Zhao, J. Q.; Yang, J.; Li, P. X.; Liu, M. Y.; Shi, Y. M.

    2016-06-01

    Accurate and timely change detection of Earth's surface features is extremely important for understanding relationships and interactions between people and natural phenomena. Many traditional methods of change detection only use a part of polarization information and the supervised threshold selection. Those methods are insufficiency and time-costing. In this paper, we present a novel unsupervised change-detection method based on quad-polarimetric SAR data and automatic threshold selection to solve the problem of change detection. First, speckle noise is removed for the two registered SAR images. Second, the similarity measure is calculated by the test statistic, and automatic threshold selection of KI is introduced to obtain the change map. The efficiency of the proposed method is demonstrated by the quad-pol SAR images acquired by Radarsat-2 over Wuhan of China.

  13. 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

  14. 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

  15. 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.

  16. 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

  17. 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.

  18. Classification comparisons between dual-pol, compact polarimetric and quad-pol SAR imagery

    NASA Astrophysics Data System (ADS)

    Ainsworth, T. L.; Kelly, J. P.; Lee, J.-S.

    We present a study of the polarimetric information content of dual-pol imaging modes and dual-pol imaging extended by polarimetric scattering models. We compare Wishart classifications both among the partial polarimetric datasets and against the full quad-pol dataset. Our emphasis is the inter-comparisons between the classification results based on dual-pol modes, compact polarimetric modes and scattering model extensions of the compact polarimetric modes. We primarily consider novel dual-pol modes, e.g. transmitting a circular polarization and receiving horizontal and vertical polarizations, and the pseudo-quad-pol data derived from polarimetric scattering models based on dual-pol data. We show that the overall classification accuracy of the pseudo-quad-pol data is essential the same as the classification accuracy obtained directly employing the underlying dual-pol imagery.

  19. Retrieval of the thickness of undeformed sea ice from simulated C-band compact polarimetric SAR images

    NASA Astrophysics Data System (ADS)

    Zhang, Xi; Dierking, Wolfgang; Zhang, Jie; Meng, Junmin; Lang, Haitao

    2016-07-01

    In this paper we introduce a parameter for the retrieval of the thickness of undeformed first-year sea ice that is specifically adapted to compact polarimetric (CP) synthetic aperture radar (SAR) images. The parameter is denoted as the "CP ratio". In model simulations we investigated the sensitivity of the CP ratio to the dielectric constant, ice thickness, ice surface roughness, and radar incidence angle. From the results of the simulations we deduced optimal sea ice conditions and radar incidence angles for the ice thickness retrieval. C-band SAR data acquired over the Labrador Sea in circular transmit and linear receive (CTLR) mode were generated from RADARSAT-2 quad-polarization images. In comparison with results from helicopter-borne measurements, we tested different empirical equations for the retrieval of ice thickness. An exponential fit between the CP ratio and ice thickness provides the most reliable results. Based on a validation using other compact polarimetric SAR images from the same region, we found a root mean square (rms) error of 8 cm and a maximum correlation coefficient of 0.94 for the retrieval procedure when applying it to level ice between 0.1 and 0.8 m thick.

  20. 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.

  1. 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).

  2. 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

  3. 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

  4. Performance analysis of fiber optic concrete stress sensors in polarimetric and white-light interferometric configurations applicable to nuclear facilities

    NASA Astrophysics Data System (ADS)

    Bock, Wojtek J.; Urbanczyk, Waclaw; Voet, Marc R. H.

    1994-12-01

    In this paper we discuss two particular topologies of fiber-optic sensors developed recently at the Laboratory of Optoelectronics at UQAH, based on pressure induced birefringence effects occurring in HB fibers, and both in temperature-compensating configurations. We present a thorough analysis of the performance of our first industrial prototype of fiber-optic stress cell developed around the concept of polarimetric pressure sensor. This prototype is based on all- fiber configuration and uses a Corning highly birefringent fiber for sensing, for temperature compensation and for transmission of light signal; a 3M polarizing fiber is also employed as a distributed polarizer. The leading input and output HB fibers are connectorized to the semiconductor laser diode and to the portable electronic detection unit. Metrological data presented in this paper show an overall accuracy of the system better than 1% of full scale in the pressure range up to 21 MPa, including stability, repeatability and temperature drift in the range of about 35 degree(s)C. Both pressure hysteresis effects and sensitivity of the leading fibers to external perturbations are negligible, and the excellent power budget of the sensor allows for remote operation up to several kilometers. The paper presents also a novel configuration of the white-light interferometric pressure sensor based entirely on HB fibers and employing electronic scanning to improve mechanical stability of the receiving interferometer, where the white-light interference pattern registered by the CCD detector is transversally shifted with pressure. We present metrological evaluation of the laboratory prototype of this sensor for the pressures up to 40 MPa for the temperatures from 10 to 35 deg. C. We also evaluate the application of coherence multiplexing for networking this type of sensors.

  5. 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

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. The use of multifrequency and polarimetric SIR-C/X-SAR data in geologic studies of Bir Safsaf, Egypt

    USGS Publications Warehouse

    Schaber, G.G.; McCauley, J.F.; Breed, C.S.

    1997-01-01

    Bir Safsaf, within the hyperarid 'core' of the Sahara in the Western Desert of Egypt, was recognized following the SIR-A and SIR-B missions in the 1980s as one of the key localities in northeast Africa, where penetration of dry sand by radar signals delineates previously unknown, sand-buried paleodrainage valleys ('radar-rivers') of middle Tertiary to Quaternary age. The Bir Safsaf area was targeted as a focal point for further research in sand penetration and geologic mapping using the multifrequency and polarimetric SIR-C/X-SAR sensors. Analysis of the SIR-C/X-SAR data from Bir Safsaf provides important new information on the roles of multiple SAR frequency and polarimetry in portraying specific types of geologic units, materials, and structures mostly hidden from view on the ground and on Landsat TM images by a relatively thin, but extensive blanket of blow sand. Basement rock units (granitoids and gneisses) and the fractures associated with them at Bir Safsaf are shown here for the first time to be clearly delineated using C- and L-band SAR images. The detectability of most geologic features is dependent primarily on radar frequency, as shown for wind erosion patterns in bedrock at X-band (3 cm wavelength), and for geologic units and sand and clay-filled fractures in weathered crystal-line basement rocks at C-band (6 cm) and L-band (24 cm). By contrast, Quaternary paleodrainage channels are detectable at all three radar frequencies owing, among other things, to an usually thin cover of blow sand. The SIR-C/X-SAR data investigated to date enable us to make specific recommendations about the utility of certain radar sensor configurations for geologic and paleoenvironmental reconnaissance in desert regions.Analysis of the shuttle imaging radar-C/X-synthetic aperture radar (SIR-C/X-SAR) data from Bir Safsaf provides important new information on the roles of multiple SAR frequency and polarimetry in portraying specific types of geologic units, materials, and

  14. 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.

  15. 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.

  16. Terrain topography measurement using multipass polarimetric synthetic aperture radar data

    NASA Astrophysics Data System (ADS)

    Schuler, Dale L.; Lee, Jong-Sen; Ainsworth, Thomas L.; Grunes, Mitchell R.

    2000-05-01

    A method has been investigated for the measurement of topography using airborne fully polarimetric synthetic aperture radar (SAR) data. Terrain slopes in both the range and azimuthal directions have been estimated using multipass flight geometries. Using these slope values, the Poisson equation was then solved to create a Digital Elevation Model (DEM) of the terrain topography. The method measures polarimetric orientation angles which are then converted into terrain slopes in the azimuthal direction. The conversion of these orientation angles into terrain slopes requires additional knowledge of the radar look angle and the range direction terrain slopes. The solution for slopes is, therefore, a problem coupled between the range and azimuthal directions. For specialized multipass flight geometries these orthogonal terrain slopes are solved for, and maps of terrain slopes are produced. In particular, the processing of two-pass orthogonal and two-pass antiparallel (headings Θ and Θ+ 180°) NASA - Jet Propulsion Laboratory airborne SAR data sets has been carried out for an area in central California. When orthogonal slopes are derived using either of these data sets, a digital elevation model may be generated. The L band, polarimetric SAR (POLSAR) DEM created by this solution is compared to a coregistered C band, interferometric SAR (IFSAR) DEM. Similar comparisons are made for terrain slopes in the azimuthal - range directions which are generated by the POLSAR and IFSAR elevation data. The polarimetric SAR, operating from an aircraft, or satellite, in a strip-mapping mode, is capable of measuring terrain topography for large areas provided that phase-preserving fully polarimetric data are taken. Polarimetric SAR data are also widely used for studies of crop classification, surface roughness, biomass density, and soil moisture content. All of these studies are adversely affected by scattering changes attributable to topography. The technique investigated here

  17. 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.

  18. 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.

  19. PolSAR calibration and reconstruction of hybrid polarimetric RISAT-1 data for pseudo quad-pol decomposition: a comparison with quad-pol

    NASA Astrophysics Data System (ADS)

    Kumar, Shashi; Gupta, Vivek; Gonnuru, Pratyusha; Joshi, Sushil Kumar

    2016-05-01

    A new approach to reconstruction of pseudo quad-polarized data from hybrid polarimetric data has been presented in this research. The algorithm is based on certain assumptions which were validated upon testing the aptness of the results and their comparison with true optical images of the region under study. This involved direct construction of the 3X3 coherency matrix from the 2X1 scattering matrices obtained from the hybrid polarimetric data. The reasonableness of the assumptions were tested by decomposing the reconstructed pseudo quad-pol data using a coherent decomposition mechanism. The data set used in this project was Level-1 FRS-1 Hybrid Polarimetric data and FRS-2 Quad-pol data of RISAT-1. Reliable scattering retrieval from SAR data involves the calibration of the data. Polarimetric calibration was performed on real and imaginary channels of the single look complex SAR data. The newly developed algorithm was implemented on calibrated data. To extract complete information of different scattering elements of any location, second order derivative of scattering matrix is the most suitable and widely used matrix. Coherency matrix of pseudo quad-pol obtained from hybrid polarimetric data using reconstruction algorithm was decomposed using Yamaguchi four component decomposition for scattering information extraction. The obtained surface, double-bounce and volume scattering were compared with the scattering elements of hybrid-polarimetric decomposition, m-alpha and decomposition of quad-pol data of RISAT-1. The comparison revealed that the results obtained were satisfactory and thus the assumptions made during the reconstruction of pseudo quad-pol data were reasonable for specific purposes. Further comparisons of results using different decompositions technique at pixel level comparison can help better understand the aptness of the algorithm.

  20. 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.

  1. 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.

  2. 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.

  3. Dark SPOT Detection Using Intensity and the Degree of Polarization in Fully Polarimetric SAR Images for Oil Polution Monitoring

    NASA Astrophysics Data System (ADS)

    Zakeri, F.; Amini, J.

    2015-12-01

    Oil spill surveillance is of great environmental and economical interest, directly contributing to improve environmental protection. Monitoring of oil spills using synthetic aperture radar (SAR) has received a considerable attention over the past few years, notably because of SAR data abilities like all-weather and day-and-night capturing. The degree of polarization (DoP) is a less computationally complex quantity characterizing a partially polarized electromagnetic field. The key to the proposed approach is making use of DoP as polarimetric information besides intensity ones to improve dark patches detection as the first step of oil spill monitoring. In the proposed approach first simple intensity threshold segmentation like Otsu method is applied to the image. Pixels with intensities below the threshold are regarded as potential dark spot pixels while the others are potential background pixels. Second, the DoP of potential dark spot pixels is estimated. Pixels with DoP below a certain threshold are the real dark-spot pixels. Choosing the threshold is a critical and challenging step. In order to solve choosing the appropriate threshold, we introduce a novel but simple method based on DoP of potential dark spot pixels. Finally, an area threshold is used to eliminate any remaining false targets. The proposed approach is tested on L band NASA/JPL UAVSAR data, covering the Deepwater Horizon oil spill in the Gulf of Mexico. Comparing the obtained results from the new method with conventional approaches like Otsu, K-means and GrowCut shows better achievement of the proposed algorithm. For instance, mean square error (MSE) 65%, Overall Accuracy 20% and correlation 40% are improved.

  4. Improving Ship Detection with Polarimetric SAR based on Convolution between Co-polarization Channels.

    PubMed

    Li, Haiyan; He, Yijun; Wang, Wenguang

    2009-01-01

    The convolution between co-polarization amplitude only data is studied to improve ship detection performance. The different statistical behaviors of ships and surrounding ocean are characterized a by two-dimensional convolution function (2D-CF) between different polarization channels. The convolution value of the ocean decreases relative to initial data, while that of ships increases. Therefore the contrast of ships to ocean is increased. The opposite variation trend of ocean and ships can distinguish the high intensity ocean clutter from ships' signatures. The new criterion can generally avoid mistaken detection by a constant false alarm rate detector. Our new ship detector is compared with other polarimetric approaches, and the results confirm the robustness of the proposed method.

  5. Monitoring The Dynamics Of Hyper-Saline Environments With Polarimetric SAR: Death Valley, California Example

    NASA Astrophysics Data System (ADS)

    Lasne, Y.; McDonald, K.; Paillou, P.; Freeman, A.; Chapman, B.; Farr, T.; Ruffié, G.; Malézieux, J.

    2008-12-01

    Soil salinization in arid and semi-arid regions still remains one of the most important threats not only for socio-economical issues when dealing with water ressources management, but also for ecological matters such as: desertification, climate changes, and biomass reduction. Then, monitoring and mapping of soil salinity distribution represent today a key challenge in our understanding of such environmental processes. Being highly dependent on the dielectric properties of soils, synthetic aperture radar (SAR) appears to be an efficient tool for the remote sensing of hyper-saline environments. More precisely, the influence of saline deposits on SAR imagery lies in the solubility and ionic properties of the minerals which strongly influence both real and imaginary parts of the complex permittivity of such deposits, and thus the radar backscattering coefficient. Based on temporal series acquired with spaceborne SAR systems (ALOS/PALSAR, SIR-C) over the Death Valley (CA), we show that the copolarized backscattering ratio and phase difference derived from SAR data can be used as suitable indicators to monitor the dynamics of hyper-saline deposits. In particular, we propose these copolar parameters to follow the variations in the dielectric properties of moistened and salt-affected soils on a seasonal time scale because of the close relationship between the salinity (governed by the soil moisture content) and the complex permittivity of the soils. We also highlight a strong temporal correlation between the copolar parameters and weather data since precipitation events control the soil moisture and salinity. In order to allow for a better interpretation of the saline deposits signatures observed on SAR data, we also perform analytical simulations of the radar backscattering associated with saline deposits by means of the IEM scattering model. Using laboratory and in~ situ dielectric measurements as input parameters, we simulate the copolar ratio and phase difference as

  6. Polarimetric SAR decomposition parameter subset selection and their optimal dynamic range evaluation for urban area classification using Random Forest

    NASA Astrophysics Data System (ADS)

    Hariharan, Siddharth; Tirodkar, Siddhesh; Bhattacharya, Avik

    2016-02-01

    Urban area classification is important for monitoring the ever increasing urbanization and studying its environmental impact. Two NASA JPL's UAVSAR datasets of L-band (wavelength: 23 cm) were used in this study for urban area classification. The two datasets used in this study are different in terms of urban area structures, building patterns, their geometric shapes and sizes. In these datasets, some urban areas appear oriented about the radar line of sight (LOS) while some areas appear non-oriented. In this study, roll invariant polarimetric SAR decomposition parameters were used to classify these urban areas. Random Forest (RF), which is an ensemble decision tree learning technique, was used in this study. RF performs parameter subset selection as a part of its classification procedure. In this study, parameter subsets were obtained and analyzed to infer scattering mechanisms useful for urban area classification. The Cloude-Pottier α, the Touzi dominant scattering amplitude αs1 and the anisotropy A were among the top six important parameters selected for both the datasets. However, it was observed that these parameters were ranked differently for the two datasets. The urban area classification using RF was compared with the Support Vector Machine (SVM) and the Maximum Likelihood Classifier (MLC) for both the datasets. RF outperforms SVM by 4% and MLC by 12% in Dataset 1. It also outperforms SVM and MLC by 3.5% and 11% respectively in Dataset 2.

  7. Unsupervised classification of polarimetric SAR images using complex Wishart distribution based on H/α decomposition and algorithm evaluation

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Yang, Ran

    2007-11-01

    The authors introduce unsupervised wishart classification technique for fully polarimetric SAR data using H/α decomposition of POLSAR images. This paper we applied this technique to AIRSAR data of Flevoland, Netherlands. The most valuable in this paper is our evaluation. From the following tree aspects we evaluate the algorithm mentioned in this paper and the results it produced. (i) By calculating the Jeffries-Matusit Distance (J-M Distance) J mn between two classes, which represents the separation between classes, the property of this classifier is measured. J-M Distance is a measurement of average difference between Probability Distribution Function (PDF) of two classes. Usually J-M Distance is between 0 and 2, and the bigger J-M Distance represents that two classes has a good separation. This paper we have most J-M Distances 1.8-2.0, thus indicates good separation; (ii) According to the average entropy and alpha of each final class, the classification results are analyzed; (iii) by comparing the classification results with the ground truth, the classification algorithm is evaluated. The results have a good simulation of ground truth. Experiment in this paper, according to the measurement criterion, analysis and evaluation, demonstrates that the region of Flevoland is well classification and the method has the advantage of edge holding that in the case of non-smooth borders this advantage is helpful. Also this paper gives a better repeat time.

  8. Techniques Deriving Land Cover and Earth Surface Deformation Information from Polarimetric SAR Interferometry- Final Report

    NASA Astrophysics Data System (ADS)

    Pottier, E.; Chen, E.; Li, Z.; Hong, W.; Xiang, M.; Li, Y.; Cloude, S. R.; Papathanassiou, K.; Zhang, L.; Li, X.

    2013-01-01

    In this paper we provide a summary of activities carried out under the DRAGON collaborative program in a project concerned with the application of Pol-InSAR to deriving land cover and Earth Surface deformation information. This project (ID. 5344) is based around four main scientific topics: Land Cover Analysis, Earth Surface Deformation Monitoring and DEM Extraction, Forest Vertical Structure Parameters Extraction and PolSARpro Software Development.

  9. 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.

  10. Improved Model-Based Polarimetric Decomposition Using the POlINSAR Similarity Parameter

    NASA Astrophysics Data System (ADS)

    Latrache, H.; Ouarzeddine, M.; Souissi, B.

    2016-06-01

    In this paper, we present a new approach to solve the problem of volume scattering ambiguity in urban area, for that we propose a volume model based on the polarimetric interferometric similarity parameter (PISP) . The new model is more adaptive and fits better with both forest and oriented built-up areas. Thereby, a new model-based polarimetric decomposition scheme is developed. To test the performance of the proposed method ESAR PolInSAR L bande data of Oberpfaffenhofen, Germany is used. Comparison experiments show that the proposed method gives good results, since all the oriented built-up areas are well discriminated as double or odd bounce structures.

  11. 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.

  12. 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.

  13. 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

  14. Comparative analysis of RISAT-1 and simulated RADARSAT-2 hybrid polarimetric SAR data for different land features

    NASA Astrophysics Data System (ADS)

    Kumar, V.; Rao, Y. S.

    2014-11-01

    The purpose of this study is to compare the performance of first hybrid polarimetric spaceborne satellite RISAT-1 data and simulated hybrid polarimetric data from quad-pol RADARSAT-2 data for different land use land cover (LULC) classes. The present study compares Stokes (g0, g1, g2 and g3) and its decomposed parameters (m, chi, delta and CPR) for satellite data acquired from RISAT- 1 and RADARSAT-2 over Vijayawada, Andhra Pradesh, India. Further, backscattering coefficients are also compared for different LULC types. The results indicate that both the satellites are following approximately the same trend for different classes except for settlements in RISAT-1.

  15. 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.

  16. 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

  17. 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.

  18. Comparison of C-Band and X-Band Polarimetric SAR Data for River Ice Classification on the Peace River

    NASA Astrophysics Data System (ADS)

    Łoś, H.; Osińska-Skotak, K.; Pluto-Kossakowska, J.; Bernier, M.; Gauthier, Y.; Jasek, M.; Roth, A.

    2016-06-01

    In this study, synthetic aperture radar (SAR) data from TerraSAR-X were compared with RADARSAT-2 data to evaluate their effectiveness for river ice monitoring on the Peace River. For several years RADARSAT-2 data have been successfully used for river ice observation. However, it is important to take into account data from other satellites as they may provide solutions when it is not possible to obtain images from the preferred system (e.g., in the case of acquisition priority conflicts). In this study we compared three TerraSAR-X (X-band) and three RADARSAT-2 (C-band) datasets acquired in December 2013 on a section of the Peace River, Canada. For selected classes (open water, skim ice, juxtaposed skim ice, agglomerated skim ice, frazil run and consolidated ice) we compared backscattering values in HH and VV polarisation and performed Wishart supervised classification. Covariance matrices that were previously filtered using a refined Lee filter were used as input data for classification. For all data sets the overall accuracy was higher than 80%. Similar errors associated with classification output were observed for data from both satellite systems.

  19. 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.

  20. 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.

  1. 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.

  2. Effect of Medium Symmetries in Limiting the Number of Parameters Estimated with Polarimetric Interferometry

    NASA Technical Reports Server (NTRS)

    Moghaddam, Mahta

    2000-01-01

    The addition of interferometric backscattering pairs to the conventional polarimetric 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 vegetation parameters. Without regard to the sensitivity of these data to vegetation scattering parameters, this paper poses the question: Will increasing the data channels as such result in a one-to-one increase in the number of parameters that can be estimated, or do vegetation and data properties inherently limit that number otherwise? In this paper, the complete polarimetric interferometric covariance matrix is considered and various symmetry properties of the scattering medium are used to study whether any of the correlation pairs can be eliminated. The number of independent pairs has direct consequences in their utility in parameter estimation schemes, since the maximum number of parameters that can be estimated cannot exceed the number of unique measurements. The independent components of the polarimetric interferometric SAR (POL/INSAR) data are derived for media with reflection, rotation, and azimuth symmetries, which are often encountered in vegetated surfaces. Similar derivations have been carried out before for simple polarimetry, i.e., zero baseline. This paper extends those to the interferometric case of general nonzero baselines. It is shown that depending on the type of symmetries present, the number of independent available measurements that can be used to estimate medium parameters will vary. In particular, whereas in the general case there are 27 mathematically independent measurements possible from a polarimetric interferometer, this number can be reduced to 15, 9, and 6 if the medium has reflection, rotation, or azimuthal symmetries, respectively. The results can be used in several ways in the interpretation of SAR data and the development of parameter estimation schemes, which will be discussed at the

  3. 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

  4. 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.

  5. Overview and Applications of UAVSAR's Multi-Squint Polarimetric Imaging Mode

    NASA Technical Reports Server (NTRS)

    Scott Hensley; Chen, Curtis; Michel, Thierry; Jones, Cathleen; Chapman, Bruce; Muellerschoen, Ron

    2011-01-01

    NASA's Jet Propulsion Laboratory has developed a reconfigurable polarimetric L-band synthetic aperture radar (SAR), specifically designed to acquire airborne repeat track interferometric (RTI) SAR data for application to monitoring surface deformation and vegetation structure measurements. The system employs a precision autopilot developed by NASA Dryden that allows the plane to fly precise trajectories usually within a 5 m tube. Also required for robust repeat pass applications is the ability to point the antenna in the same direction on repeat passes to a fraction of an azimuth beamwidth (8? for UAVSAR). This precise pointing is achieved using an electronically scanned antenna whose pointing is based on inertial navigation unit (INU) attitude angle data. The radar design is fully polarimetric with an 80 MHz bandwidth (2 m range resolution) and has a greater than 20 km range swath when flying at its nominal altitude of 12500 m. The ability to electronically steer the beam on a pulse-to-pulse basis has allowed a new mode of SAR data acquisition whereby the radar beam is steered to different squint angles on successive pulses thereby simultaneously generating images at multiple squint angles. This mode offers the possibility of generating vector deformation measurements with a single pair of repeat passes and to obtain greater kz diversity for vegetation studies with a reduced number of passes. This paper will present an overview of the mode, discuss its potential for deformation and vegetation, and show some examples using UAVSAR data.

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. SAR Polarimetry for Oil at Sea Observation

    NASA Astrophysics Data System (ADS)

    Migliaccio, M.; Nunziata, F.

    2013-03-01

    Synthetic aperture radar (SAR) oil slick observation is a topic of great applicative relevance which has been physically recast by a set of new polarimetric approaches that, exploiting the departure from Bragg scattering, allow observing oil at sea in a very robust and effective way. In this study, these polarimetric approaches are reviewed and their performances are discussed with respect to some thought experiments undertaken on quad-pol full-resolution L- and C-band SAR data.

  16. 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.

  17. 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

  18. POLCAL - POLARIMETRIC RADAR CALIBRATION

    NASA Technical Reports Server (NTRS)

    Vanzyl, J.

    1994-01-01

    Calibration of polarimetric radar systems is a field of research in which great progress has been made over the last few years. POLCAL (Polarimetric Radar Calibration) is a software tool intended to assist in the calibration of Synthetic Aperture Radar (SAR) systems. In particular, POLCAL calibrates Stokes matrix format data produced as the standard product by the NASA/Jet Propulsion Laboratory (JPL) airborne imaging synthetic aperture radar (AIRSAR). POLCAL was designed to be used in conjunction with data collected by the NASA/JPL AIRSAR system. AIRSAR is a multifrequency (6 cm, 24 cm, and 68 cm wavelength), fully polarimetric SAR system which produces 12 x 12 km imagery at 10 m resolution. AIRSTAR was designed as a testbed for NASA's Spaceborne Imaging Radar program. While the images produced after 1991 are thought to be calibrated (phase calibrated, cross-talk removed, channel imbalance removed, and absolutely calibrated), POLCAL can and should still be used to check the accuracy of the calibration and to correct it if necessary. Version 4.0 of POLCAL is an upgrade of POLCAL version 2.0 released to AIRSAR investigators in June, 1990. New options in version 4.0 include automatic absolute calibration of 89/90 data, distributed target analysis, calibration of nearby scenes with calibration parameters from a scene with corner reflectors, altitude or roll angle corrections, and calibration of errors introduced by known topography. Many sources of error can lead to false conclusions about the nature of scatterers on the surface. Errors in the phase relationship between polarization channels result in incorrect synthesis of polarization states. Cross-talk, caused by imperfections in the radar antenna itself, can also lead to error. POLCAL reduces cross-talk and corrects phase calibration without the use of ground calibration equipment. Removing the antenna patterns during SAR processing also forms a very important part of the calibration of SAR data. Errors in the

  19. 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).

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. Detection of land degradation with polarimetric SAR

    NASA Astrophysics Data System (ADS)

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

    1992-08-01

    Land degradation is a crucial problem facing the human race. With an ever-increasing population placing increasing stress on agricultural lands, land impoverishment has the potential for adversely impacting the food supply in many regions of the world. The Manix Basin Area of the Mojave desert has been cropped using center pivot irrigation, but since 1973 many fields have been abandoned for economic reasons. Data were collected using the JPL Airborne Synthetic Aperture Radar (AIRSAR), a multi-spectral radar polarimeter. Analysis of these data revealed unusual polarization responses which we attribute to the formation of wind ripples on the surfaces of fields which had been abandoned for more than 5 years. This conjecture was confirmed through field observations, and the observed polarization responses were effectively modelled using a second-order small perturbation model. These results demonstrate the usefulness of remote sensing techniques supported by limited field work for study of land degradation at synoptic scales.

  5. 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

  6. 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?

  7. Application of symmetry properties to polarimetric remote sensing with JPL AIRSAR data

    NASA Technical Reports Server (NTRS)

    Nghiem, S. V.; Yueh, Simon H.; Kwok, R.; Li, F. K.

    1992-01-01

    Based on symmetry properties, polarimetric remote sensing of geophysical media is studied. From the viewpoint of symmetry groups, media with reflection, rotation, azimuthal, and centrical symmetries are considered. The symmetries impose relations among polarimetric scattering coefficients, which are valid to all scattering mechanisms in the symmetrical configurations. Various orientation distributions of non-spherical scatterers can be identified from the scattering coefficients by a comparison with the symmetry calculations. Experimental observations are then analyzed for many geophysical scenes acquired with the Jet Propulsion Laboratory (JPL) airborne polarimetric SAR at microwave frequencies over sea ice and vegetation. Polarimetric characteristics of different ice types are compared with symmetry behaviors. The polarimetric response of a tropical rain forest reveals characteristics close to the centrical symmetry properties, which can be used as a distributed target to relatively calibrate polarimetric radars without any deployment of manmade calibration targets.

  8. 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

  9. Monsoon '90 - Preliminary SAR results

    NASA Technical Reports Server (NTRS)

    Dubois, Pascale C.; Van Zyl, Jakob J.; Guerra, Abel G.

    1992-01-01

    Multifrequency polarimetric synthetic aperture radar (SAR) images of the Walnut Gulch watershed near Tombstone, Arizona were acquired on 28 Mar. 1990 and on 1 Aug. 1990. Trihedral corner reflectors were deployed prior to both overflights to allow calibration of the two SAR data sets. During both overflights, gravimetric soil moisture and dielectric constant measurements were made. Detailed vegetation height, density, and water content measurements were made as part of the Monsoon 1990 Experiment. Preliminary results based on analysis of the multitemporal polarimetric SAR data are presented. Only the C-band data (5.7-cm wavelength) radar images show significant difference between Mar. and Aug., with the strongest difference observed in the HV images. Based on the radar data analysis and the in situ measurements, we conclude that these differences are mainly due to changes in the vegetation and not due to the soil moisture changes.

  10. Monsoon 1990: Preliminary SAR results

    NASA Technical Reports Server (NTRS)

    Vanzyl, Jakob J.; Dubois, Pascale; Guerra, Abel

    1991-01-01

    Multifrequency polarimetric synthetic aperture radar (SAR) images of the Walnut Gulch watershed near Tombstone, Arizona were acquired on 28 Mar. 1990 and on 1 Aug. 1990. Trihedral corner reflectors were deployed prior to both overflights to allow calibration of the two SAR data sets. During both overflights, gravimetric soil moisture and dielectric constant measurements were made. Detailed vegetation height, density, and water content measurements were made as part of the Monsoon 1990 Experiment. Preliminary results based on analysis of the multitemporal polarimetric SAR data are presented. Only the C-band data (5.7-cm wavelength) radar images show significant difference between Mar. and Aug., with the strongest difference observed in the HV images. Based on the radar data analysis and the in situ measurements, we conclude that these differences are mainly due to changes in the vegetation and not due to the soil moisture changes.

  11. 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.

  12. Optimization of Polarimetric Contrast Enhancement Based on Fisher Criterion

    NASA Astrophysics Data System (ADS)

    Deng, Qiming; Chen, Jiong; Yang, Jian

    The optimization of polarimetric contrast enhancement (OPCE) is a widely used method for maximizing the received power ratio of a desired target versus an undesired target (clutter). In this letter, a new model of the OPCE is proposed based on the Fisher criterion. By introducing the well known two-class problem of linear discriminant analysis (LDA), the proposed model is to enlarge the normalized distance of mean value between the target and the clutter. In addition, a cross-iterative numerical method is proposed for solving the optimization with a quadratic constraint. Experimental results with the polarimetric SAR (POLSAR) data demonstrate the effectiveness of the proposed method.

  13. Scanning Mueller polarimetric microscopy.

    PubMed

    Le Gratiet, Aymeric; Dubreuil, Matthieu; Rivet, Sylvain; Le Grand, Yann

    2016-09-15

    A full Mueller polarimeter was implemented on a commercial laser-scanning microscope. The new polarimetric microscope is based on high-speed polarization modulation by spectral coding using a wavelength-swept laser as a source. Calibration as well as estimation of the measurement errors of the device are reported. The acquisition of Mueller images at the speed of a scanning microscope is demonstrated for the first time. Mueller images of mineral and biological samples illustrate this new polarimetric microscopy. PMID:27628391

  14. 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.

  15. An L-band SAR for repeat pass deformation measurements on a UAV platform

    NASA Technical Reports Server (NTRS)

    Hensley, Scott; Lou, Yunling; Rosen, Paul; Wheeler, Kevin; Zebker, Howard; Madsen, Soren; Miller, Tim; Hoffman, Jim; Farra, Don

    2003-01-01

    We are proposing to develop a miniaturized polarimetric L-band synthetic aperture radar (SAR) for repeat-pass differential interferometric measurements of deformation for rapidly deforming surfaces of geophysical interest such as volcanoes or earthquakes that is to be flown on a unmanned aerial vehicle (UAV) or minimally piloted vehicle (MPV). Upon surveying the capabilities and availabilities of such aircraft, the Proteus aircraft and the ALTAIR UAV appear to meet our criteria in terms of payload capabilities, flying altitude, and endurance. To support the repeat pass deformation capability it is necessary to control flight track capability of the aircraft to be within a specified 10 m tube with a goal of 1 m. This requires real-time GPS control of the autopilot to achieve these objectives that has not been demonstrated on these aircraft. Based on the Proteus and ALTAIR's altitude of 13.7 km (45,000 ft), we are designing a fully polarimetric L-band radar with 80 MHz bandwidth and a 16 km range swath. The radar will have an active electronic beam steering antenna to achieve a Doppler centroid stability that is necessary for repeat-pass interferometry. This paper presents some of the trade studies for the platform, instrument and the expected science.

  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. Pyxis handheld polarimetric imager

    NASA Astrophysics Data System (ADS)

    Chenault, David B.; Pezzaniti, J. Larry; Vaden, Justin P.

    2016-05-01

    The instrumentation for measuring infrared polarization signatures has seen significant advancement over the last decade. Previous work has shown the value of polarimetric imagery for a variety of target detection scenarios including detection of manmade targets in clutter and detection of ground and maritime targets while recent work has shown improvements in contrast for aircraft detection and biometric markers. These data collection activities have generally used laboratory or prototype systems with limitations on the allowable amount of target motion or the sensor platform and usually require an attached computer for data acquisition and processing. Still, performance and sensitivity have been steadily getting better while size, weight, and power requirements have been getting smaller enabling polarimetric imaging for a greater or real world applications. In this paper, we describe Pyxis®, a microbolometer based imaging polarimeter that produces live polarimetric video of conventional, polarimetric, and fused image products. A polarization microgrid array integrated in the optical system captures all polarization states simultaneously and makes the system immune to motion artifacts of either the sensor or the scene. The system is battery operated, rugged, and weighs about a quarter pound, and can be helmet mounted or handheld. On board processing of polarization and fused image products enable the operator to see polarimetric signatures in real time. Both analog and digital outputs are possible with sensor control available through a tablet interface. A top level description of Pyxis® is given followed by performance characteristics and representative data.

  18. PHARUS airborne SAR concept

    NASA Astrophysics Data System (ADS)

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

    1995-11-01

    to ingest raw data from other SARs on the input side. The combination of the airborne and the ground segment, augmented by the transfer of technological knowledge needed to operate the system, will provide for an autonomous capability of the system user/owner. The PHARUS project has so far resulted in the construction of a C-band, VV-polarized research SAR (PHARS) with a 1- look resolution of 1.5 multiplied by 5 meter (5 multiplied by 5 meter at 7 independent looks) and a swath width of 6 km. This system has been extensively used for research and application projects in Europe, for purposes of mapping, land use inventory, change detection, coastal bathymetry, ship detection and ocean wave measurement. The next system recently completed is a fully polarimetric C-band system with adjustable resolution and swath width (the latter up to 20 km); this system is expected to be operational autumn 1995. The polarimetric capability will provide for a much enhanced discerning power (discrimination between e.g. forest/cultivated, various forest types, etc.). Discrimination by polarimetric signature is an alterative approach, with different possibilities and limitations, to e.g. the use of several frequencies. This paper gives an overview of the SAR research system and the results obtained with this system. The PHARUS design and use are discussed.

  19. Crop Change Assessment Using Polarimetric RADARSAT-2 Data

    NASA Astrophysics Data System (ADS)

    Liu, Chen; Shang, Jiali; Vachon, Paris W.; McNairn, Heather

    2011-03-01

    This paper studies the feasibility of monitoring crop growth cycles based on a temporal variation analysis of three elementary radar scattering mechanisms. Crop changes are assessed using RADARSAT-2 polarimetric data. The polarimetric SAR (PolSAR) analysis is based on the Pauli decomposition. Multi-temporal analysis is applied to RGB images constructed using surface scattering, double bounce and volume scattering. The crops studied in this paper are corn, cereals and soybeans. Each crop has unique physical structural characteristics and responds differently to these scattering mechanisms. By monitoring the significant changes that occur in these scattering mechanisms, the crop growth to harvest cycle can be observed and the harvest time can be estimated. In addition, a Maximum Likelihood Classification was performed on the RADARSAT-2 data to produce a crop map. An overall classification accuracy of 85% was achieved.

  20. Integrated analysis of PALSAR/Radarsat-1 InSAR and ENVISAT altimeter data for mapping of absolute water level changes in Louisiana wetlands

    USGS Publications Warehouse

    Kim, J.-W.; Lu, Zhiming; Lee, H.; Shum, C.K.; Swarzenski, C.M.; Doyle, T.W.; Baek, S.-H.

    2009-01-01

    Interferometric Synthetic Aperture Radar (InSAR) has been used to detect relative water level changes in wetlands. We developed an innovative method to integrate 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 identify double-bounce 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 (~ 40 m) relative water changes measured from ALOS PALSAR L-band and Radarsat-1 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. We anticipate that this new technique will allow retrospective reconstruction and concurrent monitoring of water conditions and flow dynamics in wetlands, especially those lacking gauge networks. ?? 2009 Elsevier Inc.

  1. 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

  2. Improved superpixel-based polarimetric synthetic aperture radar image classification integrating color features

    NASA Astrophysics Data System (ADS)

    Xing, Yanxiao; Zhang, Yi; Li, Ning; Wang, Robert; Hu, Guixiang

    2016-04-01

    Various polarimetric features including scattering matrix, covariance matrix, polarimetric decomposition results, and textural or spatial information have already been used for polarimetric synthetic aperture radar (PolSAR) image classification. However, color features are rarely involved. We propose an improved superpixel-based PolSAR image classification integrating color features. First, we extract the color information using polarimetric decomposition. Second, by combining the color and spatial information of pixels, modified simple linear iterative clustering is used to generate small regions called superpixels. Then we apply Wishart distance to the superpixels to classify them into different classes. This method is demonstrated using the L-band Flevoland PolSAR data from AirSAR and Oberpfaffenhofen PolSAR data from ESAR. The results show that this method works well for areas with homogeneous terrains like farms in terms of both classification accuracy and computational efficiency. Furthermore, the success of the proposed method signifies that more color features can be discovered in the future research works.

  3. Advancements in Estimating Crop Growth Stages Using RADARSAT-2 and Terrasar-X Polarimetric Data

    NASA Astrophysics Data System (ADS)

    Lampropoulos, G.; Li, Y.; Liu, T.

    2015-04-01

    This paper uses RADARSAT-2 quad Polarimetric Synthetic Aperture Radar (PolSAR) and TerraSAR-X dual polarimetric SAR data to monitor agriculture crop growth stages. Two RADARSAT-2 Fine Quad Wide (FQW) beam modes FQ2W and FQ10W, each with 5 sets of data and 13 sets of Stripmap TerraSAR-X data were used in the study. Both RADARSAT-2 POLSAR data and TerraSARX data were acquired in summer 2012 outside Winnipeg, Manitoba, Canada. The study was carried out to two crop types: canola and wheat, each contains 5 regions of interest from ground truth crop classification map in the image scene. Polarimetric features such as differential reflectivity bands ratio, entropy, anisotropy, alpha angle, lambda, scattering diversity and polarization index were evaluated for two crop types. The results from both RADARSAT-2 and TerraSAR-X data were compared and they demonstrated clear relationships between crop growth stages and polarimetric parameters. It is observed that entropy, lambda and differential reflectivity from both data have similar responses to crop growth stages in their common coverage period. The results were also validated using ground truth information.

  4. Resolving polarized stellar features thanks to polarimetric interferometry

    NASA Astrophysics Data System (ADS)

    Rousselet-Perraut, Karine; Chesneau, Olivier; Vakili, Farrokh; Mourard, Denis; Janel, Sebastien; Lavaud, Laurent; Crocherie, Axel

    2003-02-01

    Polarimetry is a powerful means for detecting and constraining various physical phenomena, such as scattering processes or magnetic fields, occuring in a large panel of stellar objects: extended atmospheres of hot stars, CP stars, Young Stellar Objects, Active Galaxy Nuclei, ... However, the lack of angular resolution is generally a strong handicap to drastically constrain the physical parameters and the geometry of the polarizing phenomena because of the cancelling of the polarized signal. In fact, even if stellar features are strongly polarized, the (spectro-)polarimetric signal integrated over the stellar surface rarely exceeds few percents. Coupling polarimetric and interferometric devices allows to resolve these local polarized structures and thus to constrain complex patchy stellar surfaces and/or environments such as disk topology in T Tauri stars, hot stars radiative winds or oscillations in Be star envelopes. In this article, we explain how interfero-polarimetric observables, basically the contrast and the position of the interference fringe patterns versus polarization (and even versus wavelength) are powerful to address the above scientific drivers and we emphasize on the key point of instrumental and data calibrations: since interferometric measurements are differential ones between 2 or more beams, this strongly relaxes the calibration requirements for the fringe phase observable. Prospects induced by the operation of the optical aperture synthesis arrays are also discussed.

  5. 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.

  6. 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.

  7. Application of SAR Remote Sensing in Land Surface Processes Over Tropical region

    NASA Technical Reports Server (NTRS)

    Saatchi, Sasan S.

    1996-01-01

    This paper outlines the potential applications of polarimetric SAR systems over tropical regions such as mapping land use and deforestation, forest regeneration, wetland and inundation studies, and mapping land cover types for biodiversity and habitat conservation studies.

  8. Polarimetric radar data decomposition and interpretation

    NASA Technical Reports Server (NTRS)

    Sun, Guoqing; Ranson, K. Jon

    1993-01-01

    Significant efforts have been made to decompose polarimetric radar data into several simple scattering components. The components which are selected because of their physical significance can be used to classify SAR (Synthetic Aperture Radar) image data. If particular components can be related to forest parameters, inversion procedures may be developed to estimate these parameters from the scattering components. Several methods have been used to decompose an averaged Stoke's matrix or covariance matrix into three components representing odd (surface), even (double-bounce) and diffuse (volume) scatterings. With these decomposition techniques, phenomena, such as canopy-ground interactions, randomness of orientation, and size of scatters can be examined from SAR data. In this study we applied the method recently reported by van Zyl (1992) to decompose averaged backscattering covariance matrices extracted from JPL SAR images over forest stands in Maine, USA. These stands are mostly mixed stands of coniferous and deciduous trees. Biomass data have been derived from field measurements of DBH and tree density using allometric equations. The interpretation of the decompositions and relationships with measured stand biomass are presented in this paper.

  9. External calibration of polarimetric radar images using distributed targets

    NASA Technical Reports Server (NTRS)

    Yueh, Simon H.; Nghiem, S. V.; Kwok, R.

    1992-01-01

    A new technique is presented for calibrating polarimetric synthetic aperture radar (SAR) images using only the responses from natural distributed targets. The model for polarimetric radars is assumed to be X = cRST where X is the measured scattering matrix corresponding to the target scattering matrix S distorted by the system matrices T and R (in general T does not equal R(sup t)). To allow for the polarimetric calibration using only distributed targets and corner reflectors, van Zyl assumed a reciprocal polarimetric radar model with T = R(sup t); when applied for JPL SAR data, a heuristic symmetrization procedure is used by POLCAL to compensate the phase difference between the measured HV and VH responses and then take the average of both. This heuristic approach causes some non-removable cross-polarization responses for corner reflectors, which can be avoided by a rigorous symmetrization method based on reciprocity. After the radar is made reciprocal, a new algorithm based on the responses from distributed targets with reflection symmetry is developed to estimate the cross-talk parameters. The new algorithm never experiences problems in convergence and is also found to converge faster than the existing routines implemented for POLCAL. When the new technique is implemented for the JPL polarimetric data, symmetrization and cross-talk removal are performed on a line-by-line (azimuth) basis. After the cross-talks are removed from the entire image, phase and amplitude calibrations are carried out by selecting distributed targets either with azimuthal symmetry along the looking direction or with some well-known volume and surface scattering mechanisms to estimate the relative phases and amplitude responses of the horizontal and vertical channels.

  10. Agricultural crop harvest progress monitoring by fully polarimetric synthetic aperture radar imagery

    NASA Astrophysics Data System (ADS)

    Yang, Hao; Zhao, Chunjiang; Yang, Guijun; Li, Zengyuan; Chen, Erxue; Yuan, Lin; Yang, Xiaodong; Xu, Xingang

    2015-01-01

    Dynamic mapping and monitoring of crop harvest on a large spatial scale will provide critical information for the formulation of optimal harvesting strategies. This study evaluates the feasibility of C-band polarimetric synthetic aperture radar (PolSAR) for monitoring the harvesting progress of oilseed rape (Brassica napus L.) fields. Five multitemporal, quad-pol Radarsat-2 images and one optical ZY-1 02C image were acquired over a farmland area in China during the 2013 growing season. Typical polarimetric signatures were obtained relying on polarimetric decomposition methods. Temporal evolutions of these signatures of harvested fields were compared with the ones of unharvested fields in the context of the entire growing cycle. Significant sensitivity was observed between the specific polarimetric parameters and the harvest status of oilseed rape fields. Based on this sensitivity, a new method that integrates two polarimetric features was devised to detect the harvest status of oilseed rape fields using a single image. The validation results are encouraging even for the harvested fields covered with high residues. This research demonstrates the capability of PolSAR remote sensing in crop harvest monitoring, which is a step toward more complex applications of PolSAR data in precision agriculture.

  11. Contribution of multitemporal polarimetric synthetic aperture radar data for monitoring winter wheat and rapeseed crops

    NASA Astrophysics Data System (ADS)

    Betbeder, Julie; Fieuzal, Remy; Philippets, Yannick; Ferro-Famil, Laurent; Baup, Frederic

    2016-04-01

    This paper aims to evaluate the contribution of multitemporal polarimetric synthetic aperture radar (SAR) data for winter wheat and rapeseed crops parameters [height, leaf area index, and dry biomass (DB)] estimation, during their whole vegetation cycles in comparison to backscattering coefficients and optical data. Angular sensitivities and dynamics of polarimetric indicators were also analyzed following the growth stages of these two common crop types using, in total, 14 radar images (Radarsat-2), 16 optical images (Formosat-2, Spot-4/5), and numerous ground data. The results of this study show the importance of correcting the angular effect on SAR signals especially for copolarized signals and polarimetric indicators associated to single-bounce scattering mechanisms. The analysis of the temporal dynamic of polarimetric indicators has shown their high potential to detect crop growth changes. Moreover, this study shows the high interest of using SAR parameters (backscattering coefficients and polarimetric indicators) for crop parameters estimation during the whole vegetation cycle instead of optical vegetation index. They particularly revealed their high potential for rapeseed height and DB monitoring [i.e., Shannon entropy polarimetry (r2=0.70) and radar vegetation index (r2=0.80), respectively].

  12. Application of a New Polarimetric Filter to RADARSAT-2 Data of Deception Island (antarctic Peninsula Region) for Surface Cover Characterization

    NASA Astrophysics Data System (ADS)

    Guillaso, S.; Schmid, T.; Lopez-Martinez, J.; D'Hondt, O.

    2015-04-01

    In this paper, we describe a new approach to analyse and quantify land surface covers on Deception Island, a volcanic island located in the Northern Antarctic Peninsula region by means of fully polarimetric RADARSAT-2 (C-Band) SAR image. Data have been filtered by a new polarimetric speckle filter (PolSAR-BLF) that is based on the bilateral filter. This filter is locally adapted to the spatial structure of the image by relying on pixel similarities in both the spatial and the radiometric domains. Thereafter different polarimetric features have been extracted and selected before being geocoded. These polarimetric parameters serve as a basis for a supervised classification using the Support Vector Machine (SVM) classifier. Finally, a map of landform is generated based on the result of the SVM results.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. Automatic oil spill detection on quad polarimetric UAVSAR imagery

    NASA Astrophysics Data System (ADS)

    Rahnemoonfar, Maryam; Dhakal, Shanti

    2016-05-01

    Oil spill on the water bodies has adverse effects on coastal and marine ecology. Oil spill contingency planning is of utmost importance in order to plan for mitigation and remediation of the oceanic oil spill. Remote sensing technologies are used for monitoring the oil spills on the ocean and coastal region. Airborne and satellite sensors such as optical, infrared, ultraviolet, radar and microwave sensors are available for remote surveillance of the ocean. Synthetic Aperture Radar (SAR) is used most extensively for oil-spill monitoring because of its capability to operate during day/night and cloud-cover condition. This study detects the possible oil spill regions on fully polarimetric Uninhabited Aerial Vehicle - Synthetic Aperture Radar (UAVSAR) images. The UAVSAR image is decomposed using Cloude-Pottier polarimetric decomposition technique to obtain entropy and alpha parameters. In addition, other polarimetric features such as co-polar correlation and degree of polarization are obtained for the UAVSAR images. These features are used to with fuzzy logic based classification to detect oil spill on the SAR images. The experimental results show the effectiveness of the proposed method.

  18. Classification of earth terrain using polarimetric synthetic aperture radar images

    NASA Technical Reports Server (NTRS)

    Lim, H. H.; Swartz, A. A.; Yueh, H. A.; Kong, J. A.; Shin, R. T.; Van Zyl, J. J.

    1989-01-01

    Supervised and unsupervised classification techniques are developed and used to classify the earth terrain components from SAR polarimetric images of San Francisco Bay and Traverse City, Michigan. The supervised techniques include the Bayes classifiers, normalized polarimetric classification, and simple feature classification using discriminates such as the absolute and normalized magnitude response of individual receiver channel returns and the phase difference between receiver channels. An algorithm is developed as an unsupervised technique which classifies terrain elements based on the relationship between the orientation angle and the handedness of the transmitting and receiving polariation states. It is found that supervised classification produces the best results when accurate classifier training data are used, while unsupervised classification may be applied when training data are not available.

  19. Polarimetric Palsar Calibration

    NASA Astrophysics Data System (ADS)

    Touzi, R.; Shimada, M.

    2008-11-01

    Polarimetric PALSAR system parameters are assessed using data sets collected over various calibration sites. The data collected over the Amazonian forest permits validating the zero Faraday rotation hypotheses near the equator. The analysis of the Amazonian forest data and the response of the corner reflectors deployed during the PALSAR acquisitions lead to the conclusion that the antenna is highly isolated (better than -35 dB). Theses results are confirmed using data collected over the Sweden and Ottawa calibration sites. The 5-m height trihedrals deployed in the Sweden calibration site by the Chalmers University of technology permits accurate measurement of antenna parameters, and detection of 2-3 degree Faraday rotation during day acquisition, whereas no Faraday rotation was noted during night acquisition. Small Faraday rotation angles (2-3 degree) have been measured using acquisitions over the DLR Oberpfaffenhofen and the Ottawa calibration sites. The presence of small but still significant Faraday rotation (2-3 degree) induces a CR return at the cross-polarization HV and VH that should not be interpreted as the actual antenna cross-talk. PALSAR antenna is highly isolated (better than -35 dB), and diagonal antenna distortion matrices (with zero cross-talk terms) can be used for accurate calibration of PALSAR polarimetric data.

  20. Polarimetric Multispectral Imaging Technology

    NASA Technical Reports Server (NTRS)

    Cheng, L.-J.; Chao, T.-H.; Dowdy, M.; Mahoney, C.; Reyes, G.

    1993-01-01

    The Jet Propulsion Laboratory is developing a remote sensing technology on which a new generation of compact, lightweight, high-resolution, low-power, reliable, versatile, programmable scientific polarimetric multispectral imaging instruments can be built to meet the challenge of future planetary exploration missions. The instrument is based on the fast programmable acousto-optic tunable filter (AOTF) of tellurium dioxide (TeO2) that operates in the wavelength range of 0.4-5 microns. Basically, the AOTF multispectral imaging instrument measures incoming light intensity as a function of spatial coordinates, wavelength, and polarization. Its operation can be in either sequential, random access, or multiwavelength mode as required. This provides observation flexibility, allowing real-time alternation among desired observations, collecting needed data only, minimizing data transmission, and permitting implementation of new experiments. These will result in optimization of the mission performance with minimal resources. Recently we completed a polarimetric multispectral imaging prototype instrument and performed outdoor field experiments for evaluating application potentials of the technology. We also investigated potential improvements on AOTF performance to strengthen technology readiness for applications. This paper will give a status report on the technology and a prospect toward future planetary exploration.

  1. A Polarimetric Extension of the van Cittert-Zernike Theorem for Use with Microwave Interferometers

    NASA Technical Reports Server (NTRS)

    Piepmeier, J. R.; Simon, N. K.

    2004-01-01

    The van Cittert-Zernike theorem describes the Fourier-transform relationship between an extended source and its visibility function. Developments in classical optics texts use scalar field formulations for the theorem. Here, we develop a polarimetric extension to the van Cittert-Zernike theorem with applications to passive microwave Earth remote sensing. The development provides insight into the mechanics of two-dimensional interferometric imaging, particularly the effects of polarization basis differences between the scene and the observer.

  2. Unsupervised polarimetric synthetic aperture radar image classification based on sketch map and adaptive Markov random field

    NASA Astrophysics Data System (ADS)

    Shi, Junfei; Li, Lingling; Liu, Fang; Jiao, Licheng; Liu, Hongying; Yang, Shuyuan; Liu, Lu; Hao, Hongxia

    2016-04-01

    Markov random field (MRF) model is an effective tool for polarimetric synthetic aperture radar (PolSAR) image classification. However, due to the lack of suitable contextual information in conventional MRF methods, there is usually a contradiction between edge preservation and region homogeneity in the classification result. To preserve edge details and obtain homogeneous regions simultaneously, an adaptive MRF framework is proposed based on a polarimetric sketch map. The polarimetric sketch map can provide the edge positions and edge directions in detail, which can guide the selection of neighborhood structures. Specifically, the polarimetric sketch map is extracted to partition a PolSAR image into structural and nonstructural parts, and then adaptive neighborhoods are learned for two parts. For structural areas, geometric weighted neighborhood structures are constructed to preserve image details. For nonstructural areas, the maximum homogeneous regions are obtained to improve the region homogeneity. Experiments are taken on both the simulated and real PolSAR data, and the experimental results illustrate that the proposed method can obtain better performance on both region homogeneity and edge preservation than the state-of-the-art methods.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Efficient polarimetric BRDF transformations

    NASA Astrophysics Data System (ADS)

    Björkert, Stefan; Renhorn, Ingmar G. E.

    2016-05-01

    In order to characterize a target, the basic information that is of interest is spectral, polarization and distance. Imaging spectropolarimetry is a powerful tool for obtaining the polarization state of a scene and to discriminate manmade objects in a cluttered background. With respect to polarization, often the measurements are limited to the first three components of the Stokes vector, excluding circular polarization. The scene is therefore characterized in four directions of linear polarization, I0, I90, I45 and I135. An efficient polarimetric BRDF model defined in a local coordinate system has recently been published. The model will now be extended to a global coordinate system for linear polarized radiation. This includes the first three elements of the Stokes vector. We will provide examples for surface of intrinsically different scattering materials, bulk scattering materials and clear coated surfaces.

  8. Advanced antennas for SAR spacecraft

    NASA Technical Reports Server (NTRS)

    Gail, William B.

    1993-01-01

    Single and multi-frequency antenna concepts were developed to evaluate the feasibility of building large aperture polarimetric synthetic aperture radar (SAR) systems to be launched in low cost vehicles such as the Delta 2. The antennas are 18.9 m long by 2.6 m wide (L-band) and achieve single polarization imaging to an incidence angle of 55 degrees and dual/quad imaging to 42 degrees. When combined with strawman spacecraft designs, both concepts meet the mass and volume constraints imposed by a Delta 2 launch.

  9. 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.

  10. 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

  11. 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.

  12. Bird Migration Echoes Observed by Polarimetric Radar

    NASA Astrophysics Data System (ADS)

    Minda, Haruya; Furuzawa, Fumie A.; Satoh, Shinsuke; Nakamura, Kenji

    A C-band polarimetric radar on Okinawa Island successfully observed large-scale bird migrations over the western Pacific Ocean. The birds generated interesting polarimetric signatures. This paper describes the signatures and speculates bird behavior.

  13. Study of Oil spill in Norwegian area using Decomposition Techniques on RISAT-1 Hybrid Polarimetric Data.

    NASA Astrophysics Data System (ADS)

    Jayasri, P. V.; Usha Sundari, H. S. V.; Kumari, E. V. S. Sita; Prasad, A. V. V.

    2014-11-01

    Over past few years Synthetic Aperture Radar(SAR) has received a considerable attention for monitoring and detection of oil spill due to its unique capabilities to provide wide-area surveillance and day and night measurements, almost independently from atmospheric conditions. The critical part of the oil spill detection is to distinguish oil spills from other natural phenomena. Stokes vector analysis of the image data is studied to estimate the polarized circular and linear components of the backscatter signal which essentially utilize the degree of polarization(m) and relative phase (δ) of the target. In a controlled oil spill experiment conducted at Norwegian bay during 17th to 22nd June 2014, RISAT-1 hybrid polarimetry images were utilized to study the characteristics of oil spill in the sea. The preliminary results obtained by using polarimetric decomposition technique on hybrid polarimetric data to decipher the polarimetric characteristics of oil spills from natural waters are discussed in the paper.

  14. 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.

  15. Real time polarimetric dehazing.

    PubMed

    Mudge, Jason; Virgen, Miguel

    2013-03-20

    Remote sensing is a rich topic due to its utility in gathering detailed accurate information from locations that are not economically feasible traveling destinations or are physically inaccessible. However, poor visibility over long path lengths is problematic for a variety of reasons. Haze induced by light scatter is one cause for poor visibility and is the focus of this article. Image haze comes about as a result of light scattering off particles and into the imaging path causing a haziness to appear on the image. Image processing using polarimetric information of light scatter can be used to mitigate image haze. An imaging polarimeter which provides the Stokes values in real time combined with a "dehazing" algorithm can automate image haze removal for instant applications. Example uses are to improve visual display providing on-the-spot detection or imbedding in an active control loop to improve viewing and tracking while on a moving platform. In addition, removing haze in this manner allows the trade space for a system operational waveband to be opened up to bands which are object matched and not necessarily restricted by scatter effects. PMID:23518739

  16. Polarimetric observations of Hungaria asteroids

    NASA Astrophysics Data System (ADS)

    Gil-Hutton, R.; Lazzaro, D.; Benavidez, P.

    2007-06-01

    Aims:We present the results of a polarimetric program at Complejo Astronómico El Leoncito (Casleo), San Juan, Argentina. The aim of this campaign is to estimate the polarimetric properties of asteroids belonging to the Hungaria dynamical group. Methods: The data were obtained with the Casprof polarimeter at the 2.15 m telescope. The Casprof polarimeter is a two-hole aperture polarimeter with rapid modulation. The campaign began in 2000, and data on a sample of 24 members of the Hungaria group were obtained. We use the slope - albedo or P_min - albedo relationships to get polarimetric albedos for 18 of these objects. Results: Only two Xe-type objects, 434 Hungaria and 3447 Burkhalter, shown a polarimetric behavior compatible with a high albedo object. The A-type asteroid 1600 Vyssotsky has a polarimetric behavior similar to what was observed by Fornasier et al. (2006) for 863 Benkolea, and four objects show P_min values consistent with dark surfaces. Based on observations carried out at the Complejo Astronómico El Leoncito, operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the National Universities of La Plata, Córdoba, and San Juan.

  17. Towards automated mapping of lake ice using RADARSAT-2 and simulated RCM compact polarimetric data

    NASA Astrophysics Data System (ADS)

    Duguay, Claude

    2016-04-01

    The Canadian Ice Service (CIS) produces a weekly ice fraction product (a text file with a single lake-wide ice fraction value, in tenth, estimated for about 140 large lakes across Canada and northern United States) created from the visual interpretation of RADARSAT-2 ScanSAR dual-polarization (HH and HV) imagery, complemented by optical satellite imagery (AVHRR, MODIS and VIIRS). The weekly ice product is generated in support of the Canadian Meteorological Centre (CMC) needs for lake ice coverage in their operational numerical weather prediction model. CIS is interested in moving from its current (manual) way of generating the ice fraction product to a largely automated process. With support from the Canadian Space Agency, a project was recently initiated to assess the potential of polarimetric SAR data for lake ice cover mapping in light of the upcoming RADARSAT Constellation Mission (to be launched in 2018). The main objectives of the project are to evaluate: 1) state-of-the-art image segmentation algorithms and 2) RADARSAT-2 polarimetric and simulated RADARSAT Constellation Mission (RCM) compact polarimetric SAR data for ice/open water discrimination. The goal is to identify the best segmentation algorithm and non-polarimetric/polarimetric parameters for automated lake ice monitoring at CIS. In this talk, we will present the background and context of the study as well as initial results from the analysis of RADARSAT-2 Standard Quad-Pol data acquired during the break-up and freeze-up periods of 2015 on Great Bear Lake, Northwest Territories.

  18. 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

  19. Next generation SAR demonstration on space station

    SciTech Connect

    Edelstein, Wendy; Kim, Yunjin; Freeman, Anthony; Jordan, Rolando

    1999-01-22

    This paper describes the next generation synthetic aperture radar (SAR) that enables future low cost space-borne radar missions. In order to realize these missions, we propose to use an inflatable, membrane, microstrip antenna that is particularly suitable for low frequency science radar missions. In order to mitigate risks associated with this revolutionary technology, the space station demonstration will be very useful to test the long-term survivability of the proposed antenna. This experiment will demonstrate several critical technology challenges associated with space-inflatable technologies. Among these include space-rigidization of inflatable structures, controlled inflation deployment, flatness and uniform separation of thin-film membranes and RF performance of membrane microstrip antennas. This mission will also verify the in-space performance of lightweight, high performance advanced SAR electronics. Characteristics of this SAR instrument include a capability for high resolution polarimetric imaging. The mission will acquire high quality scientific data using this advanced SAR to demonstrate the utility of these advanced technologies. We will present an inflatable L-band SAR concept for commercial and science applications and a P-band design concept to validate the Biomass SAR mission concept. The ionospheric effects on P-band SAR images will also be examined using the acquired data.

  20. Metamaterials for terahertz polarimetric devices

    SciTech Connect

    O'hara, John F; Taylor, Antoinette J; Smirnova, Evgenya; Azad, Abul; Chen, Hou-tong; Peralta, Xomalin G; Brener, Igal

    2008-01-01

    We present experimental and numerical investigations of planar terahertz metamaterial structures designed to interact with the state of polarization. The dependence of metamaterial resonances on polarization results in unique amplitude and phase characteristics of the terahertz transmission, providing the basis for polarimetric terahertz devices. We highlight some potential applications for polarimetric devices and present simulations of a terahertz quarter-wave plate and a polarizing terahertz beam splitter. Although this work was performed at tcrahertz frequencies, it may find applications in other frequency ranges as well.

  1. Metamaterials for terahertz polarimetric devices

    SciTech Connect

    O'hara, John F; Taylor, Antoinette J; Smirnova, Evgenya; Azad, Abul

    2008-01-01

    We present experimental and numerical investigations of planar terahertz metamaterial structures designed to interact with the state of polarization. The dependence of metamaterial resonances on polarization results in unique amplitude and phase characteristics of the terahertz transmission, providing the basis for polarimetric terahertz devices. We highlight some potential applications for polarimetric devices and present simulations of a terahertz quarter-wave plate and a polarizing terahertz beam splitter. Although this work was performed at terahertz frequencies, it may find applications in other frequency ranges as well.

  2. 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.

  3. 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.

  4. Oil spill analysis by means of full polarimetric UAVSAR (L-band) and Radarsat-2 (C-band) products acquired during Deepwater Horizon Disaster

    NASA Astrophysics Data System (ADS)

    Latini, Daniele; Del Frate, Fabio; Jones, Cathleen E.

    2014-10-01

    SAR instruments with polarimetric capabilities, high resolution and short revisit time can provide powerful support in oil spill monitoring and different techniques of analysis have been developed for this purpose [1][2]. An oil film on the sea surface results in darker areas in SAR images, but careful interpretation is required because dark spots can also be caused by natural phenomena. In view of the very low backscatter from slicks, the Noise Equivalent Sigma Zero (NESZ) is a primary sensor parameter to be considered when using a sensor for slick analysis. Among the existing full polarimetric sensors, the high resolution and very low NESZ values of UAVSAR (L-band) and RADARSAT-2 (C-band) make them preferable for oil spill analysis compared to the last generation SAR instruments. The Deepwater Horizon disaster that occurred in the Gulf of Mexico in 2010 represents a unique and extensive test site where large amounts of SAR imagery and ground validation data are available. By applying the Cloude-Pottier decomposition method to full polarimetric UAVSAR (L-band) and RADARSAT-2 (C-band), it is possible to extract parameters that describe the scattering mechanism of the target. By comparing quasi-simultaneous acquisitions and exploiting the different penetration capabilities of the sensors, we investigate the potential of full polarimetric SAR to discriminate oil on the sea surface from look-alike phenomena covering the full range of backscattering values down to those at the instrument noise floor.

  5. The ROHP-PAZ mission and the polarimetric and non-polarimetric effects of rain and other fozen hydrometeors on GNSS Radio-Occultation signals.

    NASA Astrophysics Data System (ADS)

    De La Torre Juarez, M.; Padulles, R.; Cardellach, E.; Tomás, S.; Turk, J.; Ao, C. O.; Oliveras, S.; Rius, A.

    2015-12-01

    The Radio Occultation and Heavy Precipitation experiment aboard the PAZ Low Earth Orbiter (ROHP-PAZ) will test, for the first time, the new polarimetric radio occultation (RO) concept. This is a mission of opportunity: The Spanish Ministry of Science and Innovation (MICINN) approved in 2009 a proposal to include a polarimetric Global Navigation Satellite System (GNSS) RO payload on board of the Spanish Earth Observation satellite PAZ. The launch of the satellite is scheduled for October 2015, and it will be followed by a 6-month commissioning phase period and has an expected life of 7 years, with a goal of 10 years.The concept is similar to that used in some polarimetric weather radars: to measure the differential phase shift between the two polarimetric components of the received signal, although in this case we will use the forward scattering geometry instead of the backscattering one. It will allow us to retrieve precipitation and other hydrometeors information, and simultaneous thermodynamic vertical profiles which will help to the understanding of the thermodynamic processes beyond heavy rain events. A sensitivity analysis has been performed, showing that the rain-induced effect is above PAZ detectability threshold in 90% of the events with along-ray averaged rain rate higher than 5 mm/h. Also, a ground field campaign has been conducted prior to the launch of the satellite. The measurements from the campaign have shown the first experimental evidences that precipitation and frozen hydrometeors induce a noticeable effect into the polarimetric RO observables. We will present here the actual status of the mission and the results from the field campaign. We will also discuss the results of the theoretical study of the thermodynamics and the effects of rain and frozen hydrometeors into standard and polarimetric RO, based on a large collocation exercise of COSMIC and TerrasSar-X with TRMM, GPM and CloudSat.

  6. InfoTerra/TerraSAR initiative

    NASA Astrophysics Data System (ADS)

    Wahl, Manfred W.

    2004-01-01

    The overarching goal of the InfoTerra/TerraSAR Initiative is to establish a self-sustaining operational/commercial business built on Europe"s know-how and experience in space-borne Synthetic Aperture Radar (SAR) technology, in SAR data processing as well as in SAR applications. InfoTerra stands for a new business concept based on supplying innovative geo-information products and services. TerraSAR is a space and ground system conceived to consist of an initial deployment and operation of 2 Radar satellites (one in X- and one in L-band) flying in a tandem configuration in the same orbit. The design of TerraSAR is driven by the market and is user-oriented. TerraSAR is key to capturing a significant proportion of the existing market and to opening new market opportunities, when it becomes operational. The InfoTerra/TerraSAR Initiative has evolved gradually. It started in 1997 as a joint venture between German (DSS) and British (MMS-UK) space industry, strongly supported by both space agencies, DLR and BNSC. In early 2001, DLR and BNSC submitted to ESA the Formal Programme Proposal for InfoTerra/TerraSAR to become an essential element of ESA"s Earth Watch Programme. In summer 2001, when it became evident that there was not yet sufficient support from the ESA Member States to allow immediate start entering into TerraSAR Phase C/D, it has been decided to implement first a TerraSAR consolidation phase. In early 2002, in order to avoid further delays, a contract was signed between DLR and Astrium GmbH on the development of one component of TerraSAR, the TerraSAR-X, in the frame of a national programme, governed by a Public Private Partnership Agreement. Even if now the different launch dates for TerraSAR-X and TerraSAR-L are narrowing down the window of common data acquisition, it is a reasonable starting point, but it should always be kept in mind that the utmost goal for the longterm is to achieve self sustainability by supplying geo-information products and services

  7. Optical Polarimetric Mapping of Ceres

    NASA Astrophysics Data System (ADS)

    Yang, Bin; Li, Jian-Yang; Kelley, Michael S.

    2016-10-01

    The dwarf planet Ceres, with one quarter of its mass possibly as water, is of particular importance to understanding the origin and the evolution history of water in the inner solar system. It is also a real-life laboratory to study astrobiology. NASA's Dawn is returning detailed geological maps of Ceres until the end of this year. As a complement to the Dawn mission, using SPHERE/ZIMPOL at one of Very Large Telescopes in Chile, we obtained the optical polarimetric maps in the I and V band of the whole surface of Ceres in July and August, 2015. Polarimetric maps of Ceres are sensitive to the physical conditions (such as packing density and particle size distribution) and composition of its surface regolith. The comparative studies between our polarimetric maps and Dawn maps help us to understand the geological evolution and the space weathering processes on Ceres' surface. At the time of the ZIMPOL observations, with the best spatial resolution of about 0.02 arcsecond (equivalent to 30 km), we effectively obtained about 700 independent measurements of the surface in one polarimetric set. I will present the SPHERE observations and discuss our major findings.

  8. 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.

  9. Object-oriented change detection based on weighted polarimetric scattering differences on POLSAR images

    NASA Astrophysics Data System (ADS)

    Shi, X.; Lu, L.; Yang, S.; Huang, G.; Zhao, Z.

    2015-06-01

    For wide application of change detection with SAR imagery, current processing technologies and methods are mostly based on pixels. It is difficult for pixel-based technologies to utilize spatial characteristics of images and topological relations of objects. Object-oriented technology takes objects as processing unit, which takes advantage of the shape and texture information of image. It can greatly improve the efficiency and reliability of change detection. Recently, with the development of polarimetric synthetic aperture radar (PolSAR), more backscattering features on different polarization state can be available for usage of object-oriented change detection study. In this paper, the object-oriented strategy will be employed. Considering the fact that the different target or target's state behaves different backscattering characteristics dependent on polarization state, an object-oriented change detection method that based on weighted polarimetric scattering difference of PolSAR images is proposed. The method operates on the objects generated by generalized statistical region merging (GSRM) segmentation processing. The merit of GSRM method is that image segmentation is executed on polarimetric coherence matrix, which takes full advantages of polarimetric backscattering features. And then, the measurement of polarimetric scattering difference is constructed by combining the correlation of covariance matrix and the difference of scattering power. Through analysing the effects of the covariance matrix correlation and the scattering echo power difference on the polarimetric scattering difference, the weighted method is used to balance the influences caused by the two parts, so that more reasonable weights can be chosen to decrease the false alarm rate. The effectiveness of the algorithm that proposed in this letter is tested by detection of the growth of crops with two different temporal radarsat-2 fully PolSAR data. First, objects are produced by GSRM algorithm

  10. Polarimetric Observations of σ Orionis E

    NASA Astrophysics Data System (ADS)

    Carciofi, A. C.; Faes, D. M.; Townsend, R. H. D.; Bjorkman, J. E.

    2013-03-01

    Some massive stars possess strong magnetic fields that confine plasma in the circumstellar environment. These magnetospheres have been studied spectroscopically, photometrically, and, more recently, interferometrically. Here we report on the first firm detection of a magnetosphere in continuum linear polarization, as a result of monitoring σ Ori E at the Pico dos Dias Observatory. The non-zero intrinsic polarization indicates an asymmetric structure whose minor elongation axis is oriented 150.°0 east of the celestial north. A modulation of the polarization was observed with a period of half of the rotation period, which supports the theoretical prediction of the presence of two diametrally opposed, corotating blobs of gas. A phase lag of -0.085 was detected between the polarization minimum and the primary minimum of the light curve, suggestive of a complex shape of the plasma clouds. We present a preliminary analysis of the data with the Rigidly Rotating Magnetosphere model, which could not reproduce simultaneously the photometric and polarimetric data. A toy model comprising two spherical corotating blobs joined by a thin disk proved more successful in reproducing the polarization modulation. With this model we were able to determine that the total scattering mass of the thin disk is similar to the mass of the blobs (2M b/M d = 1.2) and that the blobs are rotating counterclockwise on the plane of the sky. This result shows that polarimetry can provide a diagnostic of the geometry of clouds, which will serve as an important constraint for improving the Rigidly Rotating Magnetosphere model.

  11. POLARIMETRIC OBSERVATIONS OF {sigma} ORIONIS E

    SciTech Connect

    Carciofi, A. C.; Faes, D. M.; Townsend, R. H. D.; Bjorkman, J. E.

    2013-03-20

    Some massive stars possess strong magnetic fields that confine plasma in the circumstellar environment. These magnetospheres have been studied spectroscopically, photometrically, and, more recently, interferometrically. Here we report on the first firm detection of a magnetosphere in continuum linear polarization, as a result of monitoring {sigma} Ori E at the Pico dos Dias Observatory. The non-zero intrinsic polarization indicates an asymmetric structure whose minor elongation axis is oriented 150. Degree-Sign 0 east of the celestial north. A modulation of the polarization was observed with a period of half of the rotation period, which supports the theoretical prediction of the presence of two diametrally opposed, corotating blobs of gas. A phase lag of -0.085 was detected between the polarization minimum and the primary minimum of the light curve, suggestive of a complex shape of the plasma clouds. We present a preliminary analysis of the data with the Rigidly Rotating Magnetosphere model, which could not reproduce simultaneously the photometric and polarimetric data. A toy model comprising two spherical corotating blobs joined by a thin disk proved more successful in reproducing the polarization modulation. With this model we were able to determine that the total scattering mass of the thin disk is similar to the mass of the blobs (2M{sub b}/M{sub d} = 1.2) and that the blobs are rotating counterclockwise on the plane of the sky. This result shows that polarimetry can provide a diagnostic of the geometry of clouds, which will serve as an important constraint for improving the Rigidly Rotating Magnetosphere model.

  12. Polarimetric analysis of snow-covered and bare lake ice from Ku and X-band scatterometer data

    NASA Astrophysics Data System (ADS)

    Ben Khadhra, K.; Gunn, G. E.; Duguay, C. R.; Kelly, R. E.

    2011-12-01

    Lake ice plays a key role in regional climate, and has significant physical, biological and socio-economic impacts (e.g. fish overwintering habitat, winter-road transportation, public safety). In the last two decades, there has been growing interest by the international remote sensing community to explore radar polarimetry for glaciological investigations, mainly for glaciers and ice sheet. Polarimetric synthetic aperture radar (SAR) could be a potential tool for lake ice cover mapping and ice thickness estimation. In this paper, we represent results from the first investigation of fully polarimetric Ku and X-band (9.6 and 17.2 GHz, respectively) scatterometer data collected over lake near Churchill, Manitoba. Several controlled and calibrated experimental measurements were carried out during winter 2010-2011, as a contribution to the Cold Regions Hydrology High-resolution Observatory (CoReH2O) candidate mission of the European Space Agency (ESA). Scatterometer scans were made on several occasions at five undisturbed static sites on Ramsey Lake. Measurements characterizing snow and ice properties were also gathered immediately after scatterometer scans. Snow depth and density, snow water equivalent, gain size, ice thickness, ice composition and air inclusion in ice volume were determined at each site. This field data set was very important for the interpretation of the polarimetric parameters, e.g. the copolarization ratio, the copolarization phase and the depolarization ratio. First, the polarimetric parameters have been analysed for the two layers (snow and ice) covariance matrix and where snow subsequently removed. Thus, the influence of the snow layer on the polarimetric data could be quantified. Also, the Pauli and Cloude/Pottier polarimetric decompositions were applied for the two-layer and one-layer scattering mechanisms (removed snow) to quantify the effectiveness of these decompositions. Results show that the polarimetric SAR could explain the different

  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. Development Of Polarimetric Decomposition Techniques For Indian Forest Resource Assessment Using Radar Imaging Satellite (Risat-1) Images

    NASA Astrophysics Data System (ADS)

    Sridhar, J.

    2015-12-01

    The focus of this work is to examine polarimetric decomposition techniques primarily focussed on Pauli decomposition and Sphere Di-Plane Helix (SDH) decomposition for forest resource assessment. The data processing methods adopted are Pre-processing (Geometric correction and Radiometric calibration), Speckle Reduction, Image Decomposition and Image Classification. Initially to classify forest regions, unsupervised classification was applied to determine different unknown classes. It was observed K-means clustering method gave better results in comparison with ISO Data method.Using the algorithm developed for Radar Tools, the code for decomposition and classification techniques were applied in Interactive Data Language (IDL) and was applied to RISAT-1 image of Mysore-Mandya region of Karnataka, India. This region is chosen for studying forest vegetation and consists of agricultural lands, water and hilly regions. Polarimetric SAR data possess a high potential for classification of earth surface.After applying the decomposition techniques, classification was done by selecting region of interests andpost-classification the over-all accuracy was observed to be higher in the SDH decomposed image, as it operates on individual pixels on a coherent basis and utilises the complete intrinsic coherent nature of polarimetric SAR data. Thereby, making SDH decomposition particularly suited for analysis of high-resolution SAR data. The Pauli Decomposition represents all the polarimetric information in a single SAR image however interpretation of the resulting image is difficult. The SDH decomposition technique seems to produce better results and interpretation as compared to Pauli Decomposition however more quantification and further analysis are being done in this area of research. The comparison of Polarimetric decomposition techniques and evolutionary classification techniques will be the scope of this work.

  15. 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

  16. Ionospheric Specifications for SAR Interferometry (ISSI)

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  17. 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.

  18. Symmetry in polarimetric remote sensing

    NASA Technical Reports Server (NTRS)

    Nghiem, S. V.; Yueh, S. H.; Kwok, R.

    1993-01-01

    Relationships among polarimetric backscattering coefficients are derived from the viewpoint of symmetry groups. For both reciprocal and non-reciprocal media, symmetry encountered in remote sensing due to reflection, rotation, azimuthal, and centrical symmetry groups is considered. The derived properties are general and valid to all scattering mechanisms, including volume and surface scatterings and their interactions, in a given symmetrical configuration. The scattering coefficients calculated from theoretical models for layer random media and rough surfaces are shown to obey the symmetry relations. Use of symmetry properties in remote sensing of structural and environmental responses of scattering media is also discussed. Orientations of spheroidal scatterers described by spherical, uniform, planophile, plagiothile, erectophile, and extremophile distributions are considered to derive their polarimetric backscattering characteristics. These distributions can be identified from the observed scattering coefficients by comparison with theoretical symmetry calculations. A new parameter is then defined to study scattering structures in geophysical media. Observations from polarimetric data acquired by the Jet Propulsion Laboratory airborne synthetic aperture radar over forests, sea ice, and sea surface are presented. Experimental evidences of the symmetry relationships are shown and their use in polarimetric remote sensing is illustrated. For forests, the coniferous forest in Mt. Shasta area (California) and mixed forest near Presque Isle (Maine) exhibit characteristics of the centrical symmetry at C-band. For sea ice in the Beaufort Sea, multi-year sea ice has a cross-polarized ratio e close to e(sub 0), calculated from symmetry, due to the randomness in the scattering structure. First-year sea ice has e much smaller than e(sub 0) due to the preferential alignment of the columnar structure of the ice. From polarimetric data of a sea surface in the Bering Sea, it is

  19. 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 ...

  20. Relative Astrometry of Compact Flaring Structures in Sgr A* with Polarimetric Very Long Baseline Interferometry

    NASA Astrophysics Data System (ADS)

    Johnson, Michael D.; Fish, Vincent L.; Doeleman, Sheperd S.; Broderick, Avery E.; Wardle, John F. C.; Marrone, Daniel P.

    2014-10-01

    We demonstrate that polarimetric interferometry can be used to extract precise spatial information about compact polarized flares of Sgr A*. We show that, for a faint dynamical component, a single interferometric baseline suffices to determine both its polarization and projected displacement from the quiescent intensity centroid. A second baseline enables two-dimensional reconstruction of the displacement, and additional baselines can self-calibrate using the flare, enhancing synthesis imaging of the quiescent emission. We apply this technique to simulated 1.3 mm wavelength observations of a "hot spot" embedded in a radiatively inefficient accretion disk around Sgr A*. Our results indicate that, even with current sensitivities, polarimetric interferometry with the Event Horizon Telescope can achieve ~5 μas relative astrometry of compact flaring structures near Sgr A* on timescales of minutes.

  1. Relative astrometry of compact flaring structures in Sgr A* with polarimetric very long baseline interferometry

    SciTech Connect

    Johnson, Michael D.; Doeleman, Sheperd S.; Fish, Vincent L.; Broderick, Avery E.; Wardle, John F. C.; Marrone, Daniel P.

    2014-10-20

    We demonstrate that polarimetric interferometry can be used to extract precise spatial information about compact polarized flares of Sgr A*. We show that, for a faint dynamical component, a single interferometric baseline suffices to determine both its polarization and projected displacement from the quiescent intensity centroid. A second baseline enables two-dimensional reconstruction of the displacement, and additional baselines can self-calibrate using the flare, enhancing synthesis imaging of the quiescent emission. We apply this technique to simulated 1.3 mm wavelength observations of a 'hot spot' embedded in a radiatively inefficient accretion disk around Sgr A*. Our results indicate that, even with current sensitivities, polarimetric interferometry with the Event Horizon Telescope can achieve ∼5 μas relative astrometry of compact flaring structures near Sgr A* on timescales of minutes.

  2. 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.

  3. Cosmic Ultraviolet Polarimetric Imaging Device

    NASA Astrophysics Data System (ADS)

    Burgh, Eric B.; Nordsieck, Kenneth H.; Jaehnig, Kurt P.; Harris, Walter M.; Bershady, Matthew A.

    The Cosmic Ultraviolet Polarimetric Imaging Device (CUPID) is a suborbital sounding rocket payload designed to perform wide-field, polarimetric imaging of the extragalactic ultraviolet background. In doing so, it will also measure the contribution to the UV background from the diffuse Galactic light (DGL), starlight from the Milky Way scattered off of dust. Current uncertanties in the contribution of the DGL to the UV background are due almost entirely to a poor knowledge of the optical properties of the dust in the diffuse ISM at ultraviolet wavelengths. The polarization of the scattered light is sensitive to scattering angle and thus CUPID imaging may help to constrain the spatial distribution and scattering properties of Galactic dust.

  4. The NASA Polarimetric Radar (NPOL)

    NASA Technical Reports Server (NTRS)

    Petersen, Walter A.; Wolff, David B.

    2013-01-01

    Characteristics of the NASA NPOL S-band dual-polarimetric radar are presented including its operating characteristics, field configuration, scanning capabilities and calibration approaches. Examples of precipitation science data collections conducted using various scan types, and associated products, are presented for different convective system types and previous field campaign deployments. Finally, the NASA NPOL radar location is depicted in its home base configuration within the greater Wallops Flight Facility precipitation research array supporting NASA Global Precipitation Measurement Mission ground validation.

  5. Single-pixel polarimetric imaging.

    PubMed

    Durán, Vicente; Clemente, Pere; Fernández-Alonso, Mercedes; Tajahuerce, Enrique; Lancis, Jesús

    2012-03-01

    We present an optical system that performs Stokes polarimetric imaging with a single-pixel detector. This fact is possible by applying the theory of compressive sampling to the data acquired by a commercial polarimeter without spatial resolution. The measurement process is governed by a spatial light modulator, which sequentially generates a set of preprogrammed light intensity patterns. Experimental results are presented and discussed for an object that provides an inhomogeneous polarization distribution. PMID:22378406

  6. 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.

  7. Analysis of Radarsat-2 Full Polarimetric Data for Forest Mapping

    NASA Astrophysics Data System (ADS)

    Maghsoudi, Yasser

    Forests are a major natural resource of the Earth and control a wide range of environmental processes. Forests comprise a major part of the planet's plant biodiversity and have an important role in the global hydrological and biochemical cycles. Among the numerous potential applications of remote sensing in forestry, forest mapping plays a vital role for characterization of the forest in terms of species. Particularly, in Canada where forests occupy 45% of the territory, representing more than 400 million hectares of the total Canadian continental area. In this thesis, the potential of polarimetric SAR (PolSAR) Radarsat-2 data for forest mapping is investigated. This thesis has two principle objectives. First is to propose algorithms for analyzing the PolSAR image data for forest mapping. There are a wide range of SAR parameters that can be derived from PolSAR data. In order to make full use of the discriminative power offered by all these parameters, two categories of methods are proposed. The methods are based on the concept of feature selection and classifier ensemble. First, a nonparametric definition of the evaluation function is proposed and hence the methods NFS and CBFS. Second, a fast wrapper algorithm is proposed for the evaluation function in feature selection and hence the methods FWFS and FWCBFS. Finally, to incorporate the neighboring pixels information in classification an extension of the FWCBFS method i.e. CCBFS is proposed. The second objective of this thesis is to provide a comparison between leaf-on (summer) and leaf-off (fall) season images for forest mapping. Two Radarsat-2 images acquired in fine quad-polarized mode were chosen for this study. The images were collected in leaf-on and leaf-off seasons. We also test the hypothesis whether combining the SAR parameters obtained from both images can provide better results than either individual datasets. The rationale for this combination is that every dataset has some parameters which may be

  8. Program Merges SAR Data on Terrain and Vegetation Heights

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  9. Monitoring 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.

  10. Long-range polarimetric imaging through fog.

    PubMed

    Fade, Julien; Panigrahi, Swapnesh; Carré, Anthony; Frein, Ludovic; Hamel, Cyril; Bretenaker, Fabien; Ramachandran, Hema; Alouini, Mehdi

    2014-06-20

    We report an experimental implementation of long-range polarimetric imaging through fog over kilometric distance in real field atmospheric conditions. An incoherent polarized light source settled on a telecommunication tower is imaged at a distance of 1.3 km with a snapshot polarimetric camera including a birefringent Wollaston prism, allowing simultaneous acquisition of two images along orthogonal polarization directions. From a large number of acquisitions datasets and under various environmental conditions (clear sky/fog/haze, day/night), we compare the efficiency of using polarized light for source contrast increase with different signal representations (intensity, polarimetric difference, polarimetric contrast, etc.). With the limited-dynamics detector used, a maximum fourfold increase in contrast was demonstrated under bright background illumination using polarimetric difference image.

  11. 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.

  12. Estimation of Soil Moisture and Biomass Changes Using SAR Data During EFEDA-Spain Experiment

    NASA Technical Reports Server (NTRS)

    Saatchi, S. S.; Zyl, J. Van; Evans, D.

    1993-01-01

    During the 1991 MAC-EUROPE campaign, the Castilla La-Mancha region of Spain was surveyed by the Multi-frequency (P-,L-, C-band) polarimetric AIRSAR of Jet Propulsion Laboratory. The experiment was devised to demonstrate the role of SAR imagery in detecting and estimating surface parameters such as soil moisture and canopy water content.

  13. Estimation of Soil Moisture for Vegetated Surfaces Using Multi-Temporal L-Band SAR Measurements

    NASA Technical Reports Server (NTRS)

    Shi, Jian-Cheng; Sun, G.; Hsu, A.; Wang, J.; ONeill, P.; Ranson, J.; Engman, E. T.

    1997-01-01

    This paper demonstrates the technique to estimate ground surface and vegetation scattering components, based on the backscattering model and the radar decomposition theory, under configuration of multi-temporal L-band polarimetric SAR measurement. This technique can be used to estimate soil moisture of vegetated surface.

  14. Human polarimetric micro-doppler

    NASA Astrophysics Data System (ADS)

    Tahmoush, David; Silvious, Jerry

    2011-06-01

    Modern radars can pick up target motions other than just the principle target Doppler; they pick out the small micro-Doppler variations as well. These can be used to visually identify both the target type as well as the target activity. We model and measure some of the micro-Doppler motions that are amenable to polarimetric measurement. Understanding the capabilities and limitations of radar systems that utilize micro-Doppler to measure human characteristics is important for improving the effectiveness of these systems at securing areas. In security applications one would like to observe humans unobtrusively and without privacy issues, which make radar an effective approach. In this paper we focus on the characteristics of radar systems designed for the estimation of human motion for the determination of whether someone is loaded. Radar can be used to measure the direction, distance, and radial velocity of a walking person as a function of time. Detailed radar processing can reveal more characteristics of the walking human. The parts of the human body do not move with constant radial velocity; the small micro-Doppler signatures are timevarying and therefore analysis techniques can be used to obtain more characteristics. Looking for modulations of the radar return from arms, legs, and even body sway are being assessed by researchers. We analyze these techniques and focus on the improved performance that fully polarimetric radar techniques can add. We perform simulations and fully polarimetric measurements of the varying micro-Doppler signatures of humans as a function of elevation angle and azimuthal angle in order to try to optimize this type of system for the detection of arm motion, especially for the determination of whether someone is carrying something in their arms. The arm is often bent at the elbow, providing a surface similar to a dihedral. This is distinct from the more planar surfaces of the body and allows us to separate the signals from the arm (and

  15. 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

  16. 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.

  17. Segmenting and extracting terrain surface signatures from fully polarimetric multilook SIR-C data

    NASA Astrophysics Data System (ADS)

    Geaga, Jorge V.

    2016-05-01

    We report results from the segmenting and study of terrain surface signatures of fully polarimetric multilook L-band and C-band SIR-C data. Entropy/alpha/anisotropy decomposition features are available from single multilook pixel data. This eliminates the need to average data from several pixels. Entropy and alpha are utilized in the segmentation along with features we have developed primarily from the eigenanalysis of the Kennaugh matrices of multilook data. We have previously reported on our algorithm for segmenting fully polarimetric single look TerraSAR-X, multilook SIR-C and 7 band Landsat 5 data featuring the iterative application of a feedforward neural network with one hidden layer. A comparison of signatures from simultaneously recorded data at L and C bands is presented. The terrain surfaces surveyed include the ocean, lakes, lake ice, bare ground, desert salt flats, lava beds, vegetation, sand dunes, rough desert surfaces, agricultural and urban areas.

  18. 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.

  19. 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.

  20. 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.

  1. An improved method for polarimetric image restoration in interferometry

    NASA Astrophysics Data System (ADS)

    Pratley, Luke; Johnston-Hollitt, Melanie

    2016-11-01

    Interferometric radio astronomy data require the effects of limited coverage in the Fourier plane to be accounted for via a deconvolution process. For the last 40 years this process, known as `cleaning', has been performed almost exclusively on all Stokes parameters individually as if they were independent scalar images. However, here we demonstrate for the case of the linear polarization P, this approach fails to properly account for the complex vector nature resulting in a process which is dependent on the axes under which the deconvolution is performed. We present here an improved method, `Generalized Complex CLEAN', which properly accounts for the complex vector nature of polarized emission and is invariant under rotations of the deconvolution axes. We use two Australia Telescope Compact Array data sets to test standard and complex CLEAN versions of the Högbom and SDI (Steer-Dwedney-Ito) CLEAN algorithms. We show that in general the complex CLEAN version of each algorithm produces more accurate clean components with fewer spurious detections and lower computation cost due to reduced iterations than the current methods. In particular, we find that the complex SDI CLEAN produces the best results for diffuse polarized sources as compared with standard CLEAN algorithms and other complex CLEAN algorithms. Given the move to wide-field, high-resolution polarimetric imaging with future telescopes such as the Square Kilometre Array, we suggest that Generalized Complex CLEAN should be adopted as the deconvolution method for all future polarimetric surveys and in particular that the complex version of an SDI CLEAN should be used.

  2. Ship Detection Using SAR Polarimetry. The Development Of A New Algorithm Designed To Exploit New Satellite SAR Capabilities For Maritime Surveillance

    NASA Astrophysics Data System (ADS)

    Marino, Armando; Walker, Nick; Woodhouse, Iain

    2010-04-01

    Target detection of marine feature is a major topic for the security and monitoring of coastlines. Synthetic Aperture Radar (SAR) has been shown to be particularly useful for this application because of its all- weather and night capability. In this paper a new ship and iceberg detection methodology is described that makes novel use of the polarimetric representation of targets contained in SAR data. This polarimetric representation can be characterized by a vector with an algebraic formalism in a multi-dimensional complex space. The algorithm proposed is based on a perturbation analysis in the target space recently developed and published by the authors [1-3], which was focused on land based target detection. In this new work, the general target detector is optimised for detection of marine features like ships or icebergs. The algorithm can be considered to be a negative filter focused on sea. Consequently, all the features which have a polarimetric behaviour different from the sea are detected and considered as targets. Testing with RADARSAT-2 full polarimetric data shows significant agreement with the expected location of ships, boats and buoys, moreover the detection seems to be independent on the sea state. Further validation exercises are planned where SAR data will be acquired over regions containing ships with GPS location trackers.

  3. 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.

  4. Research on Multi-Temporal PolInSAR Modeling and Applications

    NASA Astrophysics Data System (ADS)

    Hong, Wen; Pottier, Eric; Chen, Erxue

    2014-11-01

    In the study of theory and processing methodology, we apply accurate topographic phase to the Freeman-Durden decomposition for PolInSAR data. On the other hand, we present a TomoSAR imaging method based on convex optimization regularization theory. The target decomposition and reconstruction performance will be evaluated by multi-temporal Land P-band fully polarimetric images acquired in BioSAR campaigns. In the study of hybrid Quad-Pol system performance, we analyse the expression of range ambiguity to signal ratio (RASR) in this architecture. Simulations are used to testify its advantage in the improvement of range ambiguities.

  5. 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.

  6. 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.

  7. 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.

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

    NASA Technical Reports Server (NTRS)

    Schmullius, C.; Nithack, J.

    1992-01-01

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

  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. 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

  11. 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.

  12. 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.

  13. Detection of Built-Up Areas Using Polarimetric Synthetic Aperture Radar Data and Hyperspectral Image

    NASA Astrophysics Data System (ADS)

    Bordbari, R.; Maghsoudi, Y.; Salehi, M.

    2015-12-01

    Polarimetric synthetic aperture radar (POLSAR) is an advantageous data for information extraction about objects and structures by using the wave scattering and polarization properties. Hyperspectral remote sensing exploits the fact that all materials reflect, absorb, and emit electromagnetic energy, at specific wavelengths, in distinctive patterns related to their molecular composition. As a result of their fine spectral resolution, Hyperspectral image (HIS) sensors provide a significant amount of information about the physical and chemical composition of the materials occupying the pixel surface. In target detection applications, the main objective is to search the pixels of an HSI data cube for the presence of a specific material (target). In this research, a hierarchical constrained energy minimization (hCEM) method using 5 different adjusting parameters has been used for target detection from hyperspectral data. Furthermore, to detect the built-up areas from POLSAR data, building objects discriminated from surrounding natural media presented on the scene using Freeman polarimetric target decomposition (PTD) and the correlation coefficient between co-pol and cross-pol channels. Also, target detection method has been implemented based on the different polarization basis for using the more information. Finally a majority voting method has been used for fusing the target maps. The polarimetric image C-band SAR data acquired by Radarsat-2, over San Francisco Bay area was used for the evaluation of the proposed method.

  14. Probability of detection of downed aircraft using SAR polarimetry

    NASA Astrophysics Data System (ADS)

    Chotoo, Kancham; Huxtable, Barton D.; Mansfield, Arthur W.; Rais, Houra

    2000-08-01

    In developing a beaconless search and rescue capability to quickly locate small aircraft that have crashed in remote areas, NASA's Search and Rescue Synthetic Aperture Radar (SAR2) program brings together advanced polarimetric synthetic aperture radar processing, field and laboratory tests, and state-of-the-art automated target detection algorithms. The fundamental idea underlying the search and rescue (S&R) approach is use of an airborne polarimetric radar. The downed aircraft is partly composed of metal, and consists of regular geometric shapes such as flat plates, dihedrals, trihedrals, etc., which produce a polarization signature expected to be distinct from that of surrounding terrain and foliage. Onboard polarimetric SAR image formation combined with automatic image exploitation will ultimately cue the S&R team to candidate crash sites in near real-time. We empirically examine the probability of detection (PD) and false alarm rate (FAR) for crash site detection using polarimetry to discriminate between aircraft target signatures within natural clutter. This briefing will present the latest results from the S&R Program activities, providing an update to the last program presentation to the SPIE Meeting in 1999.

  15. 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.

  16. InSAR monitoring of high risk geohazard sites

    NASA Astrophysics Data System (ADS)

    Singhroy, Vern

    InSAR techniques are increasingly being used in slope stability assessment, seismic and volcanic hazards. Our research has shown that differential InSAR and coherent target monitoring techniques using field corner reflectors are useful to monitor landslide activity along strategic transportation and energy corridors in Canada and China. We have also used InSAR techniques to monitor seismic activity on Vancouver Island. Our investigation has shown that differential InSAR and CTM techniques provide a useful monitoring technique for landslide activity under different slope, moisture and lithological conditions. On vegetated slopes, corner reflectors are being used to continuously monitor large active slopes. The series of InSAR images indicate the different level of activity of the slopes (large and small) during different periods of the year. The information produced by our InSAR activity maps are used to realign the pipeline route in sensitive permafrost areas, and to install slope stability measures along the Trans-Canada Highway. Recent RADARSAT-2 with its high resolution (3m) multi-incidence fully polarimetric capabilities are providing the high resolution rapid revisit capabilities needed to continuously monitor these active slopes along Canadian strategic energy and transportation corridors, as well as seismically active regions.

  17. 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.

  18. 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.

  19. Poyang Lake wetland vegetation biomass inversion using polarimetric RADARSAT-2 synthetic aperture radar data

    NASA Astrophysics Data System (ADS)

    Shen, Guozhuang; Liao, Jingjuan; Guo, Huadong; Liu, Ju

    2015-01-01

    Poyang Lake is the largest freshwater lake in China and one of the most important wetlands in the world. Vegetation, an important component of wetland ecosystems, is one of the main sources of the carbon in the atmosphere. Biomass can quantify the contribution of wetland vegetation to carbon sinks and carbon sources. Synthetic aperture radar (SAR), which can operate in all day and weather conditions and penetrate vegetation to some extent, can be used to retrieve information about vegetation structure and the aboveground biomass. In this study, RADARSAT-2 polarimetric SAR data were used to retrieve aboveground vegetation biomass in the Poyang Lake wetland. Based on the canopy backscatter model, the vegetation backscatter characteristics in the C-band were studied, and a good relation between simulated backscatter and backscatter in the RADARSAT-2 imagery was achieved. Using the backscatter model, pairs of training data were built and used to train the back propagation artificial neural network. The biomass was retrieved using this ANN and compared with the field survey results. The root-mean-square error in the biomass estimation was 45.57 g/m2. This shows that the combination of the model and polarimetric decomposition components can efficiently improve the inversion precision.

  20. Polarimetric Remote Sensing of Geophysical Medium Structures

    NASA Technical Reports Server (NTRS)

    Nghiem, S. V.; Yueh, S. H.; Kwok, R.; Nguyen, D. T.

    1993-01-01

    Polarimetric remote sensing of structures in geophysical media is studied in this paper based on their symmetry properties. Orientations of spheroidal scatterers described by spherical, uniform, planophile, plagiothile, erectophile, and extremophile distributions are considered to derive their polarimetric backscattering characteristics. These distributions can be identified from the observed scattering coefficients by comparison with theoretical symmetry calculations. A new parameter is defined to study scattering structures in geophysical media. Experimental observations from polarimetric data acquired by the Jet Propulsion Laboratory airborne synthetic aperture radar over forests, sea ice, and sea surface are presented to illustrate the use of symmetry properties. For forests, the coniferous forest in Mount Shasta area and mixed forests neir Presque Isle show evidence of the centrical symmetry at C band. In sea ice from the Beaufort Sea, multiyear sea ice has a cross-polarized ratio e close to e(sub 0), calculated from symmetry, due to the randomness in the scattering structure. For first-year sea ice, e is much smaller than e(sub 0) as a result of preferential alignment of the columnar structure of the ice. From polarimetric data of a sea surface in the Bering sea, it is observed that e and e(sub 0) are increasing with incident angle and e is greater than e(sub 0) at L band because of the directional feature of sea surface waves. Use of symmetry properties of geophysical media for polarimetric radar calibration is also suggested.

  1. Polarimetric remote sensing of geophysical medium structures

    NASA Astrophysics Data System (ADS)

    Nghiem, S. V.; Yueh, S. H.; Kwok, R.; Nguyen, D. T.

    1993-11-01

    Polarimetric remote sensing of structures in geophysical media is studied in this paper based on their symmetry properties. Orientations of spheroidal scatterers described by spherical, uniform, planophile, plagiothile, erectophile, and extremophile distributions are considered to derive their polarimetric backscattering characteristics. These distributions can be identified from the observed scattering coefficients by comparison with theoretical symmetry calculations. A new parameter is defined to study scattering structures in geophysical media. Experimental observations from polarimetric data acquired by the Jet Propulsion Laboratory airborne synthetic aperture radar over forests, sea ice, and sea surface are presented to illustrate the use of symmetry properties. For forests, the coniferous forest in Mount Shasta area and mixed forests near Presque Isle show evidence of the centrical symmetry at C band. In sea ice from the Beaufort Sea, multiyear sea ice has a cross-polarized ratio e close to e0, calculated from symmetry, due to the randomness in the scattering structure. For first-year sea ice, e is much smaller than e0 as a result of preferential alignment of the columnar structure of the ice. From polarimetric data of a sea surface in the Bering sea, it is observed that e and e0 are increasing with incident angle and e is greater than e0 at L band because of the directional feature of sea surface waves. Use of symmetry properties of geophysical media for polarimetric radar calibration is also suggested.

  2. Object-oriented fusion of RADARSAT-2 polarimetric synthetic aperture radar and HJ-1A multispectral data for land-cover classification

    NASA Astrophysics Data System (ADS)

    Xiao, Yan; Jiang, Qigang; Wang, Bin; Li, Yuanhua; Liu, Shu; Cui, Can

    2016-04-01

    The contribution of the integration of optical and polarimetric synthetic aperture radar (PolSAR) data to accurate land-cover classification was investigated. For this purpose, an object-oriented classification methodology that consisted of polarimetric decomposition, hybrid feature selection, and a support vector machine (SVM) was proposed. A RADARSAT-2 Fine Quad-Pol image and an HJ-1A CCD2 multispectral image were used as data sources. First, polarimetric decomposition was implemented for the RADARSAT-2 image. Sixty-one polarimetric parameters were extracted using different polarimetric decomposition methods and then merged with the main diagonal elements (T11, T22, T33) of the coherency matrix to form a multichannel image with 64 layers. Second, the HJ-1A and the multichannel images were divided into numerous image objects by implementing multiresolution segmentation. Third, 1104 features were extracted from the HJ-1A and the multichannel images for each image object. Fourth, the hybrid feature selection method that combined the ReliefF filter approach and the genetic algorithm (GA) wrapper approach (ReliefF-GA) was used. Finally, land-cover classification was performed by an SVM classifier on the basis of the selected features. Five other classification methodologies were conducted for comparison to verify the contribution of optical and PolSAR data integration and to test the superiority of the proposed object-oriented classification methodology. Comparison results show that HJ-1A data, RADARSAT-2 data, polarimetric decomposition, ReliefF-GA, and SVM have a significant contribution by improving land-cover classification accuracy.

  3. 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.

  4. 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.

  5. Symmetry properties in polarimetric remote sensing

    NASA Technical Reports Server (NTRS)

    Nghiem, S. V.; Yueh, S. H.; Kwok, R.; Li, F. K.

    1992-01-01

    This paper presents the relations among polarimetric backscattering coefficients from the viewpoint of symmetry groups. Symmetry of geophysical media encountered in remote sensing due to reflection, rotation, azimuthal, and centrical symmetry groups is considered for both reciprocal and nonreciprocal cases. On the basis of the invariance under symmetry transformations in the linear polarization basis, the scattering coefficients are related by a set of equations which restrict the number of independent parameters in the polarimetric covariance matrix. The properties derived under these transformations are general and apply to all scattering mechanisms in a given symmetrical configuration. The scattering coefficients calculated from theoretical models for layer random media and rough surfaces are shown to obey the derived symmetry relations. Use of symmetry properties in remote sensing of structural and environmental responses of scattering media is discussed. As a practical application, the results from this paper provide new methods for the external calibration of polarimetric radars without the deployment of man-made calibration targets.

  6. Laboratory goniometer approach for spectral polarimetric directionality

    NASA Astrophysics Data System (ADS)

    Furey, John; Zahniser, Shellie; Morgan, Cliff

    2016-05-01

    A two meter inner diameter goniometer provides approximately 0.1° angular positioning precision for a series of spectral and polarimetric instruments to enable measurements of the directionality of polarized reflectance from soils in the laboratory, at 10° increments along the azimuth and zenith. Polarimetric imaging instruments to be mounted on the goniometer, with linear polarizers in rotators in front of each instrument, include broadband focal plane array imagers in the Visible band (Vis), Near InfraRed (NIR), Short Wave InfraRed (SWIR), and Long Wave InfraRed (LWIR) spectral bands, as well as a hyperspectral imager in the Vis through NIR. Two additional hyperspectral polarimetric imagers in the Vis through NIR, and SWIR, are to be mounted separately with angles measured by laser on the goniometer frame.

  7. Stellar Rotation Effects in Polarimetric Microlensing

    NASA Astrophysics Data System (ADS)

    Sajadian, Sedighe

    2016-07-01

    It is well known that the polarization signal in microlensing events of hot stars is larger than that of main-sequence stars. Most hot stars rotate rapidly around their stellar axes. The stellar rotation creates ellipticity and gravity-darkening effects that break the spherical symmetry of the source's shape and the circular symmetry of the source's surface brightness respectively. Hence, it causes a net polarization signal for the source star. This polarization signal should be considered in polarimetric microlensing of fast rotating stars. For moderately rotating stars, lensing can magnify or even characterize small polarization signals due to the stellar rotation through polarimetric observations. The gravity-darkening effect due to a rotating source star creates asymmetric perturbations in polarimetric and photometric microlensing curves whose maximum occurs when the lens trajectory crosses the projected position of the rotation pole on the sky plane. The stellar ellipticity creates a time shift (i) in the position of the second peak of the polarimetric curves in transit microlensing events and (ii) in the peak position of the polarimetric curves with respect to the photometric peak position in bypass microlensing events. By measuring this time shift via polarimetric observations of microlensing events, we can evaluate the ellipticity of the projected source surface on the sky plane. Given the characterizations of the FOcal Reducer and low dispersion Spectrograph (FORS2) polarimeter at the Very Large Telescope, the probability of observing this time shift is very small. The more accurate polarimeters of the next generation may well measure these time shifts and evaluate the ellipticity of microlensing source stars.

  8. 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.

  9. Theoretical models for polarimetric radar clutter

    NASA Technical Reports Server (NTRS)

    Borgeaud, M.; Shin, R. T.; Kong, J. A.

    1987-01-01

    The Mueller matrix and polarization covariance matrix are described for polarimetric radar systems. The clutter is modeled by a layer of random permittivity, described by a three-dimensional correlation function, with variance, and horizontal and vertical correlation lengths. This model is applied, using the wave theory with Born approximations carried to the second order, to find the backscattering elements of the polarimetric matrices. It is found that 8 out of 16 elements of the Mueller matrix are identically zero, corresponding to a covariance matrix with four zero elements. Theoretical predictions are matched with experimental data for vegetation fields.

  10. Polarimetric applications to identify bee honey

    NASA Astrophysics Data System (ADS)

    Espinosa-Luna, Rafael; Saucedo-Orozco, Izcoatl; Santiago-Lona, Cynthia V.; Franco-Sánchez, Juan M.; Magallanes-Luján, Alejandro

    2011-10-01

    A polarimetric characterization, consisting of the Mueller matrix determination and the measurement of the refractive index, is employed to study bee honey and corn syrup differences. Two samples of commercial marks of bee honey and one sample of commercial mark corn syrup are studied. Results show the corn syrup and one of the bee honey samples have a similar polarimetric behavior, which differs from the second bee honey sample. This behavior can be employed as a simple, qualitative test, to discriminate true bee honey from corn syrup or from adulterated bee honey.s-powe

  11. Finite electron temperature effects on interferometric and polarimetric measurements in fusion plasmas

    NASA Astrophysics Data System (ADS)

    Mirnov, V. V.; Ding, W. X.; Brower, D. L.; Van Zeeland, M. A.; Carlstrom, T. N.

    2007-10-01

    Finite electron temperature effects on interferometry and polarimetry measurements for burning plasma are considered with particular focus on analytically understanding the role of weakly relativistic effects. Development of a new iterative technique, in the limit when the probing wave frequency is much higher than the electron cyclotron frequency, yields the dispersion relation to lowest (linear) order in Te/mec2≪1. Perturbative treatment of the wave phase and polarization is presented in a form suitable for interpretation of experimental data. Previous analysis of the problem included nonrelativistic calculations only. Herein, it is shown that relativistic effects are equally important. Theoretical results are in agreement with computations and can be used for benchmarking of ray tracing codes. The implication of finite temperature effects on future burning plasma interferometer diagnostics is discussed.

  12. 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

  13. Estimation of Boreal Forest Biomass Using Spaceborne SAR Systems

    NASA Technical Reports Server (NTRS)

    Saatchi, Sassan; Moghaddam, Mahta

    1995-01-01

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

  14. 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.

  15. 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

  16. 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.

  17. Software for Generating Strip Maps from SAR Data

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  18. 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.

  19. Polarimetric Signatures Identification for Different Features in RADARSAT-2 Polsar Image: a Case Study of Halayib Area, Egypt

    NASA Astrophysics Data System (ADS)

    Nasr, Ayman H.; Abdelhamid, Hind Z.

    2016-06-01

    In fully polarized SAR (PolSAR) data the returned signal from a target contains all polarizations. More information about this target may be inferred with respect to single-polarization. Distinct polarization separates targets due to its different backscattering responses. A Radarsat-2 PolSAR image acquired on December 2013 of part of Halayib area (Egypt) was used in this study. Polarimetric signatures for various features (Wadi deposits, Tonalite, Chlorite schist, and Radar penetrated areas) were derived and identified. Their Co-polarized and Cross-polarized signatures were generated, based on the calculation of the backscattered power at various ellipticity and orientation angles. Graphical 3D-representation of these features was provided and more details of their physical information are depicted according to their different polarization bases. The results illustrate that polarimetric signatures, obtained due to factors like surface roughness, dielectric constant and feature orientation, can be an effective representation for analyzing various features. The shape of the signature is significant and can also indicate the scattering mechanisms dominating the features response.

  20. 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.

  1. Subsurface polarimetric migration imaging for full polarimetric ground-penetrating radar

    NASA Astrophysics Data System (ADS)

    Feng, Xuan; Yu, Yue; Liu, Cai; Fehler, Michael

    2015-08-01

    Polarization is a property of electromagnetic wave that generally refers to the locus of the electric field vector, which can be used to characterize surface properties by polarimetric radar. However, its use has been less common in the ground-penetrating radar (GPR) community. Full polarimetric GPR data include scattering matrices, by which the polarization properties can be extracted, at each survey point. Different components of the measured scattering matrix are sensitive to different types of subsurface objects, which offers a potential improvement in the detection ability of GPR. This paper develops a polarimetric migration imaging method. By merging the Pauli polarimetric decomposition technique with the Krichhoff migration equation, we develop a polarimetric migration algorithm, which can extract three migrated coefficients that are sensitive to different types of objects. Then fusing the three migrated coefficients, we can obtain subsurface colour-coded reconstructed object images, which can be employed to interpret both the geometrical information and the scattering mechanism of the subsurface objects. A 3-D full polarimetric GPR data set was acquired in a laboratory experiment and was used to test the method. In the laboratory experiment, four objects-a scatterer, a ball, a plate and a dihedral target-were buried in homogeneous dry sand under a flat ground surface. By merging the reconstructed image with polarization properties, we enhanced the subsurface image and improved the classification ability of GPR.

  2. A snow wetness retrieval algorithm for SAR

    NASA Technical Reports Server (NTRS)

    Shi, Jian-Cheng; Dozier, Jeff

    1992-01-01

    The objectives of this study are: (1) to evaluate the backscattering signals response to snow wetness; and (2) to develop an algorithm for snow wetness measurement using C-band polarimetric synthetic aperture radar (SAR). In hydrological investigations, modeling and forecasting of snowmelt runoff requires information about snowpack properties and their spatial variability. In particular, timely measurement of snow parameters is needed for operational hydrology. The liquid water content of snowpack is one of the important parameters. Active microwave sensors are highly sensitive to liquid water in the snowpack because of the large dielectric contrast between ice and water in the microwave spectrum. They are not affected by weather and have a spatial resolution compatible with the topographic variation in alpine regions. However, a quantitative algorithm for retrieval snow wetness has not yet been developed.

  3. Passive Polarimetric Microwave Signatures Observed Over Antarctica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    WindSat satellite-based fully polarimetric passive microwave observations, expressed in the form of the Stokes vector, were analyzed over the Antarctic ice sheet. The vertically and horizontally polarized brightness temperatures (first two Stokes components) from WindSat are shown to be consistent w...

  4. Polarimetric optical imaging of scattering surfaces.

    PubMed

    Barter, J D; Lee, P H

    1996-10-20

    A polarimetric optical specular event detector (OSED) has been developed to provide spatially and temporally resolved polarimetric data of backscattering in the visible from water wave surfaces. The OSED acquires simultaneous, two-dimensionally resolved images of the remote target in two orthogonal planes of polarization. With the use of plane-polarized illumination the OSED presently can measure, in an ensemble of breaking waves, the equivalent four-element polarization matrix common to polarimetric radars. Upgrade to full Stokes parameter state of polarization measurements is straightforward with the use of present single-aperture, multi-imager CCD camera technology. The OSED is used in conjunction with a coherent pulse-chirped radar (PCR), which also measures the four-element polarization matrix, to provide direct time-correlated identification of backscattering mechanisms operative during wave-breaking events which heretofore have not been described theoretically. We describe the instrument and its implementation, and examples of spatially resolved polarimetric data are displayed as correlated with the PCR backscatter cross section and polarization ratio records.

  5. 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.

  6. Hybrid-Polarity SAR Architecture for Sea Oil Slick Monitoring

    NASA Astrophysics Data System (ADS)

    Buono, A.; Nunziata, F.; Li, X.; Wei, Y.; Ding, X.

    2014-11-01

    In this study, Compact Polarimetry (CP) architectures are exploited for oil slicks at sea observation purposes. In particular, Hybrid-Polarity (HP) architecture, which consists of transmitting a circularly-polarized field while receiving coherently according to a linear h-v base, is investigated. Basic concepts of wave polarimetry are used to define HP features for oil slicks monitoring. Experiments are undertaken on HP measurements emulated from actual C-band Full-Polarimetric (FP) Synthetic Aperture Radar (SAR) data. HP features performance in terms of oil slick detection and discrimination (from look-alikes and between different kinds of oil) is shown to be very close to the FP one.

  7. 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.

  8. 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.

  9. 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.

  10. Mapping Deforestation and Land Use in Amazon Rainforest Using SAR-C Imagery

    NASA Technical Reports Server (NTRS)

    Saatchi, Sasan S.; Soares, Joao Vianei; Alves, Diogenes Salas

    1996-01-01

    Land use changes and deforestation in tropical rainforests are among the major factors affecting the overall function of the global environment. To routinely assess the spatial extend and temporal dynamics of these changes has become an important challenge in several scientific disciplines such as climate and environmental studies. In this paper, the feasibility of using polarimetric spaceborne SAR data in mapping land cover types in the Amazon is studied.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. Snow density retrieval using SAR data: algorithm validation and applications in part of North Western Himalaya

    NASA Astrophysics Data System (ADS)

    Thakur, P. K.; Garg, R. D.; Aggarwal, S. P.; Garg, P. K.; Snehmani; Shi, J.

    2013-05-01

    The current study has been done using Polarimetric Synthetic Aperture Radar (SAR) data to estimate the dry snow density in Manali sub-basin of Beas River located in state of Himachal Pradesh, India. SAR data from Radarsat-2 (RS2), Environmental Satellite (ENVISAT), Advanced Synthetic Aperture Radar (ASAR) and Advanced Land Observing Satellite (ALOS)-Phased Array type L-band Synthetic Aperture Radar (PALSAR) have been used. The SAR based inversion models were implemented separately for fully polarimetric RS2, PALSAR and dual polarimetric ASAR Alternate polarization System (APS) datasets in Mathematica and MATLAB software and have been used for finding out dry snow dielectric constant and snow density. Masks for forest, built area, layover and shadow were considered in estimating snow parameters. Overall accuracy in terms of R2 value and Root Mean Square Error (RMSE) was calculated as 0.85 and 0.03 g cm-3 for snow density based on the ground truth data. The retrieved snow density is highly useful for snow avalanche and snowmelt runoff modeling related studies of this region.

  18. Multifrequency polarimetric ALOS PALSAR and RADARSAT-2 analysis over the archaeological area of Djebel Barkal (Sudan)

    NASA Astrophysics Data System (ADS)

    Patruno, Jolanda; Dore, Nicole; Pottier, Eric; Crespi, Mattia

    2013-04-01

    Differences in vegetation growth and in soil moisture content generate ground anomalies which can be linked to the presence of subsurface anthropic structures. Such evidences have been studied and observed for a long time by means of aerial photographs, thanks to planned campaigns or through the observation of historical II World War acquisitions first, and thanks to the very high spatial resolution of optical satellites later. The present research constitutes a contribution to the non-invasive archaeological investigation methodology carried out in the last years by several institutions and cultural organizations. The work aims to exploit the technique of SAR Polarimetry for the detection of surface and subsurface archaeological structures, comparing ALOS PALSAR L-band, with a central frequency of 1.27 GHz, with RADARSAT-2 C-band sensor, whose central frequency is 5.405 GHz. The choice to analyze satellite radar sensors capabilities is based on their 24-hour observations, as they are independent from Sun illumination and meteorological conditions. Moreover, they could provide additional information concerning electromagnetic properties of the target, qualities not derivable from optical images. A multi frequency comparison between the two SAR sensors has been performed over the Napatan (900-270 BC) Meroitic (270 BC-350 AD) area of Djebel Barkal, located in Sudan and inscribed in the UNESCO World Heritage List since 2003. It constitutes one of the five Napatan and Meroitic archaeological sites stretching over more than 60 km in the Nile valley, in an arid area part of Nubia. The area, not completely excavated, presents thombs, pyramids and sacred palaces. The dataset we disposed of is composed of two archived ALOS PALSAR polarimetric images and four RADARSAT-2 polarimetric data specifically acquired in the same year (2012). All the products have been then processed and integrated with the available optical data and the cartographic documentation derivable from

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. Polarimetric imaging beyond the speckle grain scale.

    PubMed

    Pouget, Lucien; Fade, Julien; Hamel, Cyril; Alouini, Mehdi

    2012-10-20

    We address an experimental Stokes imaging setup allowing one to explore the polarimetric properties of a speckle light field with spatial resolution well beyond the speckle grain scale. We detail how the various experimental difficulties inherent to such measurements can be overcome with a dedicated measurement protocol involving a careful speckle registration step. The setup and protocol are then validated on a metallic reference sample, and used to measure the state of polarization (SOP) of light in each pixel of highly resolved speckle patterns (>2000 pixels per speckle grain) resulting from the scattering of an incident coherent beam on samples exhibiting different polarimetric properties. Evolution of the SOP with spatial averaging and across adjacent speckle grains is eventually addressed.

  5. 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

  6. Polarimetric studies of polyethylene terephtalate flexible substrates

    NASA Astrophysics Data System (ADS)

    Stchakovsky, M.; Garcia-Caurel, E.; Warenghem, M.

    2008-12-01

    Polymer sheets are currently used worldwide in a wide range of applications. The manufacturing process of these sheets involves extruding machines that stretch the material in both lateral and longitudinal directions with respect to the machine direction, thus inducing birefringence. In most cases, the film obtained is optically biaxial. Polarimetric spectroscopy (Ellipsometry and Mueller Matrix) combined with conoscopic observation are the methods of choice to study these properties. In this work we report an analysis of commercially available polyethylene terephtalate (PET) films used as substrate for food packaging as well as for embedded electronic devices such as solar cells or flexible displays. Initial observation of these films through polarizing microscope in conoscopic mode reveals first the trace of optical axis plane with respect to the film surface and second, whether the optical axis is acute or not. This preliminary study allows optimal sample positioning for further polarimetric studies. The measurements and modelling are done in both reflection and transmission mode on several spectroscopic polarimetric setups from UV to NIR. The models give as a main result, the dielectric tensor of the film as well as its orientation with respect to the laboratory reference frame.

  7. 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

  8. Multiple-resolution study of Ka-band HRR polarimetric signature data

    NASA Astrophysics Data System (ADS)

    Giles, Robert H.; Kersey, William T.; McFarlin, M. Shane; Woodruff, Bobby G.; Finley, Robbin; Nixon, William E.

    2000-08-01

    SAR resolution and polarization performance studies for ATR algorithms have been the source of recent attention. Thorough investigations are often hindered by the lack of rigorously consistent high-resolution full-polarimetric signature data for a sufficient number of targets across requisite viewing angles, articulations and environmental conditions. While some evaluative performance studies of high-value structures and conceptual radar systems may be effectively studied with limited field radar data, to minimize signature acquisition costs, pose-independent studies of ATR algorithm are best served by signature libraries fashioned to encompass the complexity of the collection scenario. In response to the above requirements, the U.S. Army's National Ground Intelligence Center and Targets Management Office originated, sponsored, and directed a signature project plan to acquire multiple target signature data at Eglin, AFB using a high resolution full-polarimetric Ka-band radar. TMO and NGIC have sponsored researchers at both the Submillimeter-Wave Technology Laboratory and Simulation Technologies to analyze the trade-off between signature resolution and polarimetric features (ongoing research) of this turntable data. The signature data was acquired at five elevations spanning 5 degree to 60 degree for a T-72M1, T-72B, M1, M60-A3 and one classified vehicle. Using signal processing software established in an NGIC/STL-based signature study, researchers executed an HRR and ISAR cross-correlation study involving multiple resolutions to evaluate peak performance levels and to effectively understand signature requirements through the variability of multiple target RCS characteristics. The signature-to-signature variability quantified on the four unclassified MBTs is presented in this report, along with a description and examples of the signature analysis techniques exploited. This signature data is available from NGIC/TMO on request for Government Agencies and Government

  9. Supervised fully polarimetric classification of the Black Forest test site: From MAESTROI to MAC Europe

    NASA Technical Reports Server (NTRS)

    Degrandi, G.; Lavalle, C.; Degroof, H.; Sieber, A.

    1992-01-01

    A study on the performance of a supervised fully polarimetric maximum likelihood classifier for synthetic aperture radar (SAR) data when applied to a specific classification context: forest classification based on age classes and in the presence of a sloping terrain is presented. For the experimental part, the polarimetric AIRSAR data at P, L, and C-band, acquired over the German Black Forest near Freiburg in the frame of the 1989 MAESTRO-1 campaign and the 1991 MAC Europe campaign was used, MAESTRO-1 with an ESA/JRC sponsored campaign, and MAC Europe (Multi-sensor Aircraft Campaign); in both cases the multi-frequency polarimetric JPL Airborne Synthetic Aperture Radar (AIRSAR) radar was flown over a number of European test sites. The study is structured as follows. At first, the general characteristics of the classifier and the dependencies from some parameters, like frequency bands, feature vector, calibration, using test areas lying on a flat terrain are investigated. Once it is determined the optimal conditions for the classifier performance, we then move on to the study of the slope effect. The bulk of this work is performed using the Maestrol data set. Next the classifier performance with the MAC Europe data is considered. The study is divided into two stages: first some of the tests done on the Maestro data are repeated, to highlight the improvements due to the new processing scheme that delivers 16 look data. Second we experiment with multi images classification with two goals: to assess the possibility of using a training set measured from one image to classify areas in different images; and to classify areas on critical slopes using different viewing angles. The main points of the study are listed and some of the results obtained so far are highlighted.

  10. Opium Field Detection in South Oxfordshire Using SAR Polarimetry

    NASA Astrophysics Data System (ADS)

    Walker, Nick; Marino, Armando

    2011-03-01

    To-date the use of satellite imagery to monitor the growth of illicit crops such as marijuana, opium and coca has mostly been conducted using optical frequencies. However, it is well known that while optical imagery can be hampered by localised aerosols such as thin clouds, cirrus, haze and smoke, these do not present a problem for Synthetic Aperture Radar (SAR). In recent years a new generation of satellite borne sensors have also been equipped with enhanced polarimetric capabilities, which can potentially help with detecting and classifying different terrain types. For these reasons we believe it is useful to consider whether high resolution polarimetric SAR data can be applied to illicit crop detection.In this paper we present the results of an experiment whereby opium poppy fields were successfully detected in the south Oxfordshire region in the UK using RadarSat-2 quad-polarisation imagery. It should be noted that these crops are not being grown illicitly but instead are being cultivated for medicinal reasons in parts of the UK. It is interesting to note that the poppies cultivated for opium in the UK have white flowers rather than the more familiar red as can be seen from the photograph in Figure 1, which was taken 11 days earlier in the season compared to Figure 4 and Figure 5.

  11. On Sea Ice Characterisation By Multi-Frequency SAR

    NASA Astrophysics Data System (ADS)

    Grahn, Jakob; Brekke, Camilla; Eltoft, Torbjorn; Holt, Benjamin

    2013-12-01

    By means of polarimetric target decomposition, quad-pol SAR data of sea ice is analysed at two frequency bands. In particular, the non negative eigenvalue decomposition (NNED) is applied on L- and C-band NASA/JPL AIR- SAR data acquired over the Beaufort sea in 2004. The de- composition separates the scattered radar signal into three types, dominated by double, volume and single bounce scattering respectively. Using ground truth derived from RADARSAT-1 and meteorological data, we investigate how the different frequency bands compare in terms of these scattering types. The ground truth contains multi year ice and three types of first year ice of different age and thickness. We find that C-band yields a higher scattered intensity in most ice and scattering types, as well as a more homogeneous intensity. L-band on the other hand yields more pronounced deformation features, such as ridges. The mean intensity contrast between the two thinnest ice types is highest in the double scattering component of C- band, although the contrast of the total signal is greater in L-band. This may indicate that the choice of polarimetric parameters is important for discriminating thin ice types.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Oil source-fingerprinting in support of polarimetric radar mapping of Macondo-252 oil in Gulf Coast marshes.

    PubMed

    Ramsey, Elijah; Meyer, Buffy M; Rangoonwala, Amina; Overton, Edward; Jones, Cathleen E; Bannister, Terri

    2014-12-15

    Polarimetric synthetic aperture radar (PolSAR) data exhibited dramatic, spatially extensive changes from June 2009 to June 2010 in Barataria Bay, Louisiana. To determine whether these changes were associated with the Deepwater Horizon (DWH) oil spill, twenty-nine sediment samples were collected in 2011 from shoreline and nearshore-interior coastal marsh locations where oil was not observed visually or with optical sensors during the spill. Oil source-fingerprinting and polytopic vector analysis were used to link DWH oil to PolSAR changes. Our results prove that DWH oil extended beyond shorelines and confirm the association between presence of DWH oil and PolSAR change. These results show that the DWH oil spill probably affected much more of the southeastern Louisiana marshland than originally concluded from ground and aerial surveys and verify that PolSAR is a powerful tool for tracking oil intrusion into marshes with high probability even where contamination is not visible from above the canopy.

  1. Oil source-fingerprinting in support of polarimetric radar mapping of Macondo-252 oil in Gulf Coast marshes

    USGS Publications Warehouse

    Ramsey III, Elijah W.; Meyer, Buffy M.; Rangoonwala, Amina; Overton, Edward; Jones, Cathleen E.; Bannister, Terri

    2014-01-01

    Polarimetric synthetic aperture radar (PolSAR) data exhibited dramatic, spatially extensive changes from June 2009 to June 2010 in Barataria Bay, Louisiana. To determine whether these changes were associated with the Deepwater Horizon (DWH) oil spill, twenty-nine sediment samples were collected in 2011 from shoreline and nearshore–interior coastal marsh locations where oil was not observed visually or with optical sensors during the spill. Oil source-fingerprinting and polytopic vector analysis were used to link DWH oil to PolSAR changes. Our results prove that DWH oil extended beyond shorelines and confirm the association between presence of DWH oil and PolSAR change. These results show that the DWH oil spill probably affected much more of the southeastern Louisiana marshland than originally concluded from ground and aerial surveys and verify that PolSAR is a powerful tool for tracking oil intrusion into marshes with high probability even where contamination is not visible from above the canopy.

  2. Toward Polarimetry with GREGOR -- Testing the GREGOR Polarimetric Unit

    NASA Astrophysics Data System (ADS)

    Hofmann, A.; Rendtel, J.; Arlt, K.

    The new 1.5 m solar telescope GREGOR with modern scientific instrumentation will become operational in the near future. The GREGOR Polarimetric Unit (GPU) for the calibration of polarimetric measurements with any post-focal device has been developed at the Astrophysical Institute Potsdam (AIP). Here we describe details of the extensive test measurements made in the laboratory of the Solar Observatory ``Einsteinturm''.

  3. Comparison Between Spectral, Spatial and Polarimetric Classification of Urban and Periurban Landcover Using Temporal Sentinel - 1 Images

    NASA Astrophysics Data System (ADS)

    Roychowdhury, K.

    2016-06-01

    Landcover is the easiest detectable indicator of human interventions on land. Urban and peri-urban areas present a complex combination of landcover, which makes classification challenging. This paper assesses the different methods of classifying landcover using dual polarimetric Sentinel-1 data collected during monsoon (July) and winter (December) months of 2015. Four broad landcover classes such as built up areas, water bodies and wetlands, vegetation and open spaces of Kolkata and its surrounding regions were identified. Polarimetric analyses were conducted on Single Look Complex (SLC) data of the region while ground range detected (GRD) data were used for spectral and spatial classification. Unsupervised classification by means of K-Means clustering used backscatter values and was able to identify homogenous landcovers over the study area. The results produced an overall accuracy of less than 50% for both the seasons. Higher classification accuracy (around 70%) was achieved by adding texture variables as inputs along with the backscatter values. However, the accuracy of classification increased significantly with polarimetric analyses. The overall accuracy was around 80% in Wishart H-A-Alpha unsupervised classification. The method was useful in identifying urban areas due to their double-bounce scattering and vegetated areas, which have more random scattering. Normalized Difference Built-up index (NDBI) and Normalized Difference Vegetation Index (NDVI) obtained from Landsat 8 data over the study area were used to verify vegetation and urban classes. The study compares the accuracies of different methods of classifying landcover using medium resolution SAR data in a complex urban area and suggests that polarimetric analyses present the most accurate results for urban and suburban areas.

  4. Polarimetric 3D integral imaging in photon-starved conditions.

    PubMed

    Carnicer, Artur; Javidi, Bahram

    2015-03-01

    We develop a method for obtaining 3D polarimetric integral images from elemental images recorded in low light illumination conditions. Since photon-counting images are very sparse, calculation of the Stokes parameters and the degree of polarization should be handled carefully. In our approach, polarimetric 3D integral images are generated using the Maximum Likelihood Estimation and subsequently reconstructed by means of a Total Variation Denoising filter. In this way, polarimetric results are comparable to those obtained in conventional illumination conditions. We also show that polarimetric information retrieved from photon starved images can be used in 3D object recognition problems. To the best of our knowledge, this is the first report on 3D polarimetric photon counting integral imaging. PMID:25836861

  5. 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.

  6. Polarimetric Imaging using Two Photoelastic Modulators

    NASA Technical Reports Server (NTRS)

    Wang, Yu; Cunningham, Thomas; Diner, David; Davis, Edgar; Sun, Chao; Hancock, Bruce; Gutt, Gary; Zan, Jason; Raouf, Nasrat

    2009-01-01

    A method of polarimetric imaging, now undergoing development, involves the use of two photoelastic modulators in series, driven at equal amplitude but at different frequencies. The net effect on a beam of light is to cause (1) the direction of its polarization to rotate at the average of two excitation frequencies and (2) the amplitude of its polarization to be modulated at the beat frequency (the difference between the two excitation frequencies). The resulting modulated optical light beam is made to pass through a polarizing filter and is detected at the beat frequency, which can be chosen to equal the frame rate of an electronic camera or the rate of sampling the outputs of photodetectors in an array. The method was conceived to satisfy a need to perform highly accurate polarimetric imaging, without cross-talk between polarization channels, at frame rates of the order of tens of hertz. The use of electro-optical modulators is necessitated by a need to obtain accuracy greater than that attainable by use of static polarizing filters over separate fixed detectors. For imaging, photoelastic modulators are preferable to such other electrio-optical modulators as Kerr cells and Pockels cells in that photoelastic modulators operate at lower voltages, have greater angular acceptances, and are easier to use. Prior to the conception of the present method, polarimetric imaging at frame rates of tens of hertz using photoelastic modulators was not possible because the resonance frequencies of photoelastic modulators usually lie in the range from about 20 to about 100 kHz.

  7. 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.

  8. Polarimetric clutter modeling: Theory and application

    NASA Technical Reports Server (NTRS)

    Kong, J. A.; Lin, F. C.; Borgeaud, M.; Yueh, H. A.; Swartz, A. A.; Lim, H. H.; Shim, R. T.; Novak, L. M.

    1988-01-01

    The two-layer anisotropic random medium model is used to investigate fully polarimetric scattering properties of earth terrain media. The polarization covariance matrices for the untilted and tilted uniaxial random medium are evaluated using the strong fluctuation theory and distorted Born approximation. In order to account for the azimuthal randomness in the growth direction of leaves in tree and grass fields, an averaging scheme over the azimuthal direction is also applied. It is found that characteristics of terrain clutter can be identified through the analysis of each element of the covariance matrix. Theoretical results are illustrated by the comparison with experimental data provided by MIT Lincoln Laboratory for tree and grass fields.

  9. Polarimetric properties of the Reiner Gamma swirl

    NASA Astrophysics Data System (ADS)

    Jeong, Minsup; Kim, Sungsoo S.; Choi, Young-Jun; Garrick-Bethell, Ian

    2016-09-01

    In order to understand the regolith characteristics of the Reiner Gamma swirl, one of the most prominent lunar swirls, we analyze the correlation between the linear polarization flux Q and the intensity I of the swirl. We present comparisons between the phase function (the intensity variation with the phase angle) of the swirl and the phase functions of its neighbors using polarimetric data. We find that the swirl has unusually large Q values for given I values. We also show that the phase function of the swirl is relatively shallow compared to its neighbors. We suggest that the microstructure of the regolith on the Reiner Gamma swirl has been disrupted.

  10. 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.

  11. Analysis on the Potential of L-Band PolSAR Data for Crop Monitoring

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    In this work we have made use of quad-pol measurements at L-band acquired by DLRs E-SAR system during the AgriSAR06 campaign for analyzing time series of different polarimetric indicators over winter wheat, maize and winter rape fields on the basis of the phenological development. Also, the sensitivity to crop fields of parameters derived from hybrid-polarity SAR architecture as proposed by Raney in 2007 has been investigated. In both quad-pol and hybrid-pol cases a correlation study along the whole phenological development among observables and ground-truth measurements has been performed. We have focused the potential of some of these observables for the detection of particular crop conditions along certain periods within the whole growth season.

  12. Comparisons of wind speed retrieval methods on C-band multi-polarization SAR measurements

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    This paper compares the wind speed retrieval methods on C-band multi-polarization SAR measurements to find out the most appropriate one for each polarization data. The RADARSAT-2 SAR quad-polarization (VV+HH+VH+HV) data and NDBC buoy wind data were collocated. For VVpolarization, the retrieved wind speed are compared among four geophysical model function (GMF). For HH polarization, the retrieved wind speed are compared among four polarization ratio model (PR) based on CMOD5 GMF. For VH polarization, the retrieved wind speed are compared between two linear models. Comparisons show all of three polarimetric SAR data have the ability of retrieving wind speed. Based on the error analysis, the commendatory methods are proposed for each polarization.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Estimation of Biomass Carbon Stocks over Peat Swamp Forests using Multi-Temporal and Multi-Polratizations SAR Data

    NASA Astrophysics Data System (ADS)

    Wijaya, A.; Liesenberg, V.; Susanti, A.; Karyanto, O.; Verchot, L. V.

    2015-04-01

    The capability of L-band radar backscatter to penetrate through the forest canopy is useful for mapping the forest structure, including above ground biomass (AGB) estimation. Recent studies confirmed that the empirical AGB models generated from the L-band radar backscatter can provide favourable estimation results, especially if the data has dual-polarization configuration. Using dual polarimetry SAR data the backscatter signal is more sensitive to forest biomass and forest structure because of tree trunk scattering, thus showing better discriminations of different forest successional stages. These SAR approaches, however, need to be further studied for the application in tropical peatlands ecosystem We aims at estimating forest carbon stocks and stand biophysical properties using combination of multi-temporal and multi-polarizations (quad-polarimetric) L-band SAR data and focuses on tropical peat swamp forest over Kampar Peninsula at Riau Province, Sumatra, Indonesia which is one of the most peat abundant region in the country. Applying radar backscattering (Sigma nought) to model the biomass we found that co-polarizations (HH and VV) band are more sensitive than cross-polarization channels (HV and VH). Individual HH polarization channel from April 2010 explained > 86% of AGB. Whereas VV polarization showed strong correlation coefficients with LAI, tree height, tree diameter and basal area. Surprisingly, polarimetric anisotropy feature from April 2007 SAR data show relatively high correlations with almost all forest biophysical parameters. Polarimetric anisotropy, which explains the ratio between the second and the first dominant scattering mechanism from a target has reduced at some extent the randomness of scattering mechanism, thus improve the predictability of this particular feature in estimating the forest properties. These results may be influenced by local seasonal variations of the forest as well as moisture, but available quad-pol SAR data were unable to

  18. Assessment of tropical forest stand characteristics with multipolarization SAR data acquired over a mountainous region in Costa Rica

    NASA Technical Reports Server (NTRS)

    Wu, Shih-Tseng

    1990-01-01

    A digital terrain elevation data set was coregistered with radar data for assessing tropical forest stand characteristics. Both raw and topographically corrected L-band polarimetric radar data acquired over the tropical forests of Costa Rica were analyzed and correlated with field-collected tree parameter data to study the stand characteristics. The results of analyses using 18 out of 81 plots for sites A and B indicated that per-plot bole volume and tree volume are related to SAR data, particularly at site A. The topographically corrected SAR data appear to produce the same findings as those of uncorrected data.

  19. Leaf Area Index and Biomass Assessment over Tropical Peatland Forest Ecosystem Using ALOS PalSAR and Envisat ASAR Data

    NASA Astrophysics Data System (ADS)

    Wijaya, Arief; Susanti, Ari; Liesenberg, Veraldo; Wardhana, Wahyu; Yanto, Edi; Soeprijadi, Djoko; McFarlane, Craig; Qomar, Nurul

    2011-03-01

    Provision of accurate forest parameter properties is important as a basis for forest resources monitoring and carbon cycle assessment. The present study aims to model leaf area index (LAI), above ground biomass and carbon stocks over tropical peatland forests using single polarization SAR, full polarimetry SAR (PolSAR) data. Single band ALOS Palsar data (HH band, acquired on November 17, 2008) and polarimetric data (HH, VV, HV and VH, collected on April 4 and May 5, 2007) are used for the study. A series of ENVISAT ASAR data (5 datasets) collected in 2004 - 2005 are also used to model the forest properties. Landsat ETM data collected on January 22, 2009 is also used as a reference. The relationship between forest parameters and normalized radar backscattering is estimated using empirical models, and preliminary results show that Polarimetric SAR data has better correlations with the LAI and biomass than single polarimetry SAR data. The field data were collected during field work in March - April 2009 and the reliability of identified forest classes was also assessed from available Landsat ETM data. Analysis will be conducted on the basis of statistical correlations between radar data and modeled forest properties, such as LAI, biomass and tree age. This study focuses on a unique tropical peatland ecosystem in Kampar Peninsula, Sumatera, Indonesia, which has great potentials as carbon sinks and/or sources. Only few studies have been conducted in the study area due to limited satellite and field observation data.

  20. 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

  1. 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.

  2. Discrimination of crop types with TerraSAR-X-derived information

    NASA Astrophysics Data System (ADS)

    Sonobe, Rei; Tani, Hiroshi; Wang, Xiufeng; Kobayashi, Nobuyuki; Shimamura, Hideki

    Although classification maps are required for management and for the estimation of agricultural disaster compensation, those techniques have yet to be established. This paper describes the comparison of three different classification algorithms for mapping crops in Hokkaido, Japan, using TerraSAR-X (including TanDEM-X) dual-polarimetric data. In the study area, beans, beets, grasslands, maize, potatoes and winter wheat were cultivated. In this study, classification using TerraSAR-X-derived information was performed. Coherence values, polarimetric parameters and gamma nought values were also obtained and evaluated regarding their usefulness in crop classification. Accurate classification may be possible with currently existing supervised learning models. A comparison between the classification and regression tree (CART), support vector machine (SVM) and random forests (RF) algorithms was performed. Even though J-M distances were lower than 1.0 on all TerraSAR-X acquisition days, good results were achieved (e.g., separability between winter wheat and grass) due to the characteristics of the machine learning algorithm. It was found that SVM performed best, achieving an overall accuracy of 95.0% based on the polarimetric parameters and gamma nought values for HH and VV polarizations. The misclassified fields were less than 100 a in area and 79.5-96.3% were less than 200 a with the exception of grassland. When some feature such as a road or windbreak forest is present in the TerraSAR-X data, the ratio of its extent to that of the field is relatively higher for the smaller fields, which leads to misclassifications.

  3. Detecting subcanopy invasive plant species in tropical rainforest by integrating optical and microwave (InSAR/PolInSAR) remote sensing data, and a decision tree algorithm

    NASA Astrophysics Data System (ADS)

    Ghulam, Abduwasit; Porton, Ingrid; Freeman, Karen

    2014-02-01

    In this paper, we propose a decision tree algorithm to characterize spatial extent and spectral features of invasive plant species (i.e., guava, Madagascar cardamom, and Molucca raspberry) in tropical rainforests by integrating datasets from passive and active remote sensing sensors. The decision tree algorithm is based on a number of input variables including matching score and infeasibility images from Mixture Tuned Matched Filtering (MTMF), land-cover maps, tree height information derived from high resolution stereo imagery, polarimetric feature images, Radar Forest Degradation Index (RFDI), polarimetric and InSAR coherence and phase difference images. Spatial distributions of the study organisms are mapped using pixel-based Winner-Takes-All (WTA) algorithm, object oriented feature extraction, spectral unmixing, and compared with the newly developed decision tree approach. Our results show that the InSAR phase difference and PolInSAR HH-VV coherence images of L-band PALSAR data are the most important variables following the MTMF outputs in mapping subcanopy invasive plant species in tropical rainforest. We also show that the three types of invasive plants alone occupy about 17.6% of the Betampona Nature Reserve (BNR) while mixed forest, shrubland and grassland areas are summed to 11.9% of the reserve. This work presents the first systematic attempt to evaluate forest degradation, habitat quality and invasive plant statistics in the BNR, and provides significant insights as to management strategies for the control of invasive plants and conversation in the reserve.

  4. Late-summer sea ice segmentation with multi-polarisation SAR features in C and X band

    NASA Astrophysics Data System (ADS)

    Fors, Ane S.; Brekke, Camilla; Doulgeris, Anthony P.; Eltoft, Torbjørn; Renner, Angelika H. H.; Gerland, Sebastian

    2016-02-01

    In this study, we investigate the potential of sea ice segmentation by C- and X-band multi-polarisation synthetic aperture radar (SAR) features during late summer. Five high-resolution satellite SAR scenes were recorded in the Fram Strait covering iceberg-fast first-year and old sea ice during a week with air temperatures varying around 0 °C. Sea ice thickness, surface roughness and aerial photographs were collected during a helicopter flight at the site. Six polarimetric SAR features were extracted for each of the scenes. The ability of the individual SAR features to discriminate between sea ice types and their temporal consistency were examined. All SAR features were found to add value to sea ice type discrimination. Relative kurtosis, geometric brightness, cross-polarisation ratio and co-polarisation correlation angle were found to be temporally consistent in the investigated period, while co-polarisation ratio and co-polarisation correlation magnitude were found to be temporally inconsistent. An automatic feature-based segmentation algorithm was tested both for a full SAR feature set and for a reduced SAR feature set limited to temporally consistent features. In C band, the algorithm produced a good late-summer sea ice segmentation, separating the scenes into segments that could be associated with different sea ice types in the next step. The X-band performance was slightly poorer. Excluding temporally inconsistent SAR features improved the segmentation in one of the X-band scenes.

  5. 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.

  6. Tunable mechanical monolithic sensor with interferometric readout for low frequency seismic noise measurement

    NASA Astrophysics Data System (ADS)

    Acernese, F.; De Rosa, R.; Giordano, G.; Romano, R.; Barone, F.

    2008-03-01

    This paper describes a mechanical monolithic sensor for geophysical applications developed at the University of Salerno. The instrument is basically a monolithic tunable folded pendulum, shaped with precision machining and electric-discharge-machining, that can be used both as seismometer and, in a force-feedback configuration, as accelerometer. The monolithic mechanical design and the introduction of laser interferometric techniques for the readout implementation make it a very compact instrument, very sensitive in the low-frequency seismic noise band, with a very good immunity to environmental noises. Many changes have been produced since last version (2007), mainly aimed to the improvement of the mechanics and of the optical readout of the instrument. In fact, we have developed and tested a prototype with elliptical hinges and mechanical tuning of the resonance frequency together with a laser optical lever and a new laser interferometer readout system. The theoretical sensitivity curve both for both laser optical lever and laser interferometric readouts, evaluated on the basis of suitable theoretical models, shows a very good agreement with the experimental measurements. Very interesting scientific result, for example, is that the measured natural resonance frequency of the instrument is 70 mHz with a Q = 140 in air without thermal stabilization, demonstrating the feasibility of a monolithic FP sensor with a natural resonance frequency of the order of mHz with a more refined mechanical tuning. Results on the readout system based on polarimetric homodyne Michelson interferometer is discussed.

  7. Polarimetric PALSAR System Model Assessment and Calibration

    NASA Astrophysics Data System (ADS)

    Touzi, R.; Shimada, M.

    2009-04-01

    Polarimetric PALSAR system parameters are assessed using data sets collected over various calibration sites. The data collected over the Amazonian forest permits validating the zero Faraday rotation hypotheses near the equator. The analysis of the Amazonian forest data and the response of the corner reflectors deployed during the PALSAR acquisitions lead to the conclusion that the antenna is highly isolated (better than -35 dB). Theses results are confirmed using data collected over the Sweden and Ottawa calibration sites. The 5-m height trihedrals deployed in the Sweden calibration site by the Chalmers University of technology permits accurate measurement of antenna parameters, and detection of 2-3 degree Faraday rotation during day acquisition, whereas no Faraday rotation was noted during night acquisition. Small Faraday rotation angles (2-3 degree) have been measured using acquisitions over the DLR Oberpfaffenhofen and the Ottawa calibration sites. The presence of small but still significant Faraday rotation (2-3 degree) induces a CR return at the crosspolarization HV and VH that should not be interpreted as the actual antenna cross-talk. PALSAR antenna is highly isolated (better than -35 dB), and diagonal antenna distortion matrices (with zero cross-talk terms) can be used for accurate calibration of PALSAR polarimetric data.

  8. [Modeling and Simulation of Spectral Polarimetric BRDF].

    PubMed

    Ling, Jin-jiang; Li, Gang; Zhang, Ren-bin; Tang, Qian; Ye, Qiu

    2016-01-01

    Under the conditions of the polarized light, The reflective surface of the object is affected by many factors, refractive index, surface roughness, and so the angle of incidence. For the rough surface in the different wavelengths of light exhibit different reflection characteristics of polarization, a spectral polarimetric BRDF based on Kirchhof theory is proposee. The spectral model of complex refraction index is combined with refraction index and extinction coefficient spectral model which were got by using the known complex refraction index at different value. Then get the spectral model of surface roughness derived from the classical surface roughness measuring method combined with the Fresnel reflection function. Take the spectral model of refraction index and roughness into the BRDF model, then the spectral polarimetirc BRDF model is proposed. Compare the simulation results of the refractive index varies with wavelength, roughness is constant, the refraction index and roughness both vary with wavelength and origin model with other papers, it shows that, the spectral polarimetric BRDF model can show the polarization characteristics of the surface accurately, and can provide a reliable basis for the application of polarization remote sensing, and other aspects of the classification of substances. PMID:27228737

  9. Detailed Aerosol Characterization using Polarimetric Measurements

    NASA Astrophysics Data System (ADS)

    Hasekamp, Otto; di Noia, Antonio; Stap, Arjen; Rietjens, Jeroen; Smit, Martijn; van Harten, Gerard; Snik, Frans

    2016-04-01

    Anthropogenic aerosols are believed to cause the second most important anthropogenic forcing of climate change after greenhouse gases. In contrast to the climate effect of greenhouse gases, which is understood relatively well, the negative forcing (cooling effect) caused by aerosols represents the largest reported uncertainty in the most recent assessment of the International Panel on Climate Change (IPCC). To reduce the large uncertainty on the aerosol effects on cloud formation and climate, accurate satellite measurements of aerosol optical properties (optical thickness, single scattering albedo, phase function) and microphysical properties (size distribution, refractive index, shape) are essential. There is growing consensus in the aerosol remote sensing community that multi-angle measurements of intensity and polarization are essential to unambiguously determine all relevant aerosol properties. This presentations adresses the different aspects of polarimetric remote sensing of atmospheric aerosols, including retrieval algorithm development, validation, and data needs for climate and air quality applications. During past years, at SRON-Netherlands Instite for Space Research retrieval algorithms have been developed that make full use of the capabilities of polarimetric measurements. We will show results of detailed aerosol properties from ground-based- (groundSPEX), airborne- (NASA Research Scanning Polarimeter), and satellite (POLDER) measurements. Also we will discuss observational needs for future instrumentation in order to improve our understanding of the role of aerosols in climate change and air quality.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Forest classification using extracted PolSAR features from Compact Polarimetry data

    NASA Astrophysics Data System (ADS)

    Aghabalaei, Amir; Maghsoudi, Yasser; Ebadi, Hamid

    2016-05-01

    This study investigates the ability of extracted Polarimetric Synthetic Aperture RADAR (PolSAR) features from Compact Polarimetry (CP) data for forest classification. The CP is a new mode that is recently proposed in Dual Polarimetry (DP) imaging system. It has several important advantages in comparison with Full Polarimetry (FP) mode such as reduction ability in complexity, cost, mass, data rate of a SAR system. Two strategies are employed for PolSAR feature extraction. In first strategy, the features are extracted using 2 × 2 covariance matrices of CP modes simulated by RADARSAT-2 C-band FP mode. In second strategy, they are extracted using 3 × 3 covariance matrices reconstructed from the CP modes called Pseudo Quad (PQ) modes. In each strategy, the extracted PolSAR features are combined and optimal features are selected by Genetic Algorithm (GA) and then a Support Vector Machine (SVM) classifier is applied. Finally, the results are compared with the FP mode. Results of this study show that the PolSAR features extracted from π / 4 CP mode, as well as combining the PolSAR features extracted from CP or PQ modes provide a better overall accuracy in classification of forest.

  15. Integrated, Dual Orthogonal Antennas for Polarimetric Ground Penetrating Radar

    NASA Astrophysics Data System (ADS)

    Pauli, Mario; Wiesbeck, Werner

    2015-04-01

    developed [4]. If OFDM signals are used for the radiation, the carriers can be split in even and odd carriers and fed to the two orthogonally polarized transmit antennas. By using OFDM, the de-correlation of the two subcarrier groups becomes inherently high. Due to the orthogonality of OFDM subcarriers the de-correlation only depends on the quality of the hardware and the signal processing. They can be simultaneously radiated and received by the two antennas. This could result in a significant improvement of the GPR sensor system. The antenna has been realized and first measurements have been conducted. During the forthcoming EGU 2015 General Assembly the detailed electromagnetic background and the function of the dual linear, orthogonal polarized antenna will be presented as well as results in GPR relevant frequencies. Also, an approach of a planar feeding network will be presented. This abstract is a contribution to Session GI3.1 "Civil Engineering Applications of Ground Penetrating Radar," organized by the COST Action TU1208. References [1] Carin, L.; Kapoor, R.; Baum, C.E., "Polarimetric SAR imaging of buried landmines," IEEE Transactions on Geoscience and Remote Sensing, vol. 36 iss. 6, pp.1985-1988, 1998. [2] T. Schultze, M. Porebska, W. Wiesbeck, and I. Willms, "Onsets for the recognition of objects and image refinement using UWB Radar," in Proceedings of the German Microwave Conference GeMiC 2008, CD-ROM, Hamburg-Harburg, Germany, Mar. 2008. [3] G. Adamiuk, S. Beer, W. Wiesbeck, and T. Zwick, "Dual-Orthogonal Polarized Antenna for UWB-IR Technology," IEEE Antennas and Wireless Propagation Letters, vol. 8, pp. 981-984, Jul. 2009. [4] Adamiuk, W. Wiesbeck, and T. Zwick, "Differential Feeding as a Concept for the Realization of Broadband Dual-Polarized Antennas with Very High Polarization Purity," in 2009 IEEE International Symposium on Antennas & Propagation, Charleston, South Carolina, USA, Jun. 2009.

  16. 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.

  17. 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.

  18. 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

  19. Soil salinity estimation using RADARSAT 2 polarimetric data in arid and sub-arid regions: Morocco and Tunisia cases.

    NASA Astrophysics Data System (ADS)

    Lhissou, Rachid; Chokmani, Karem; El Harti, Abderrazak; Abdelfattah, Riadh; Barbouchi, Meriem; Ben Aissa, Nadhira

    2013-04-01

    Soil salinity is a serious environmental hazard that affects nearly 7% of the earth's surface. In Morocco and Tunisia, soil salinity affects 5% and 8% of their total area respectively. Affected areas are exposed to an overuse of renewable water resources and a chronic decline of groundwater levels. Therefore, problems of soil salinization are severe. Salinization causes negative effects on the ground; it affects agricultural production, infrastructure, water resources and biodiversity. Experimental methods for monitoring soil salinity by direct measurements in situ are very demanding of time and resources, and also very limited in terms of spatial coverage. Several studies have described the usefulness of remote sensing for mapping salinity. In fact, radar remote sensing can be an interesting tool for mapping and monitoring soil salinization by its synoptic coverage and the sensitivity of the radar signal to soil parameters at the first five centimeters of surface. The radar remote sensing could be more interesting than optical data as the soil salinity depends on the moisture variability. This study develops the potential of RADARSAT-2 polarimetric SAR data for soil salinity estimation in Tadla plain (central Morocco) and Mahdia region (Central Tunisia). These two test sites are different in their soil compositions as well as in their surface occupations. This was done in the object to compare the behavior of the radar backscattering with respect to the soil salinity variation in different environment. RADARSAT-2 data were acquired in full polarization at a rate of three acquisitions in FQ9 angular mode over Tadla plain and three acquisitions in FQ7 angular mode over Mahdia region. Based on field measurement data of electrical conductivity collected in three field campaigns over three dates simultaneously with acquisition periods of SAR satellite images, and polarimetric parameters, a two model calibration techniques are used to develop a soil salinity estimation

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

    USGS Publications Warehouse

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

    2014-01-01

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

  1. Polarimetric measures of selected variable stars

    NASA Astrophysics Data System (ADS)

    Elias, N. M., II; Koch, R. H.; Pfeiffer, R. J.

    2008-10-01

    Aims: The purpose of this paper is to summarize and interpret unpublished optical polarimetry for numerous program stars that were observed over the past decades at the Flower and Cook Observatory (FCO), University of Pennsylvania. We also make the individual calibrated measures available for long-term comparisons with new data. Methods: We employ three techniques to search for intrinsic variability within each dataset. First, when the observations for a given star and filter are numerous enough and when a period has been determined previously via photometry or spectroscopy, the polarimetric measures are plotted versus phase. If a statistically significant pattern appears, we attribute it to intrinsic variability. Second, we compare means of the FCO data to means from other workers. If they are statistically different, we conclude that the object exhibits long-term intrinsic variability. Third, we calculate the standard deviation for each program star and filter and compare it to the standard deviation estimated from comparable polarimetric standards. If the standard deviation of the program star is at least three times the value estimated from the polarimetric standards, the former is considered intrinsically variable. All of these statements are strengthened when variability appears in multiple filters. Results: We confirm the existence of an electron-scattering cloud at L1 in the β Per system, and find that LY Aur and HR 8281 possess scattering envelopes. Intrinsic polarization was detected for Nova Cas 1993 as early as day +3. We detected polarization variability near the primary eclipse of 32 Cyg. There is marginal evidence for polarization variability of the β Cepheid type star γ Peg. The other objects of this class exhibited no variability. All but one of the β Cepheid objects (ES Vul) fall on a tight linear relationship between linear polarization and E(B-V), in spite of the fact that the stars lay along different lines of sight. This dependence falls

  2. Nonlinear Polarimetric Microscopy for Biomedical Imaging

    NASA Astrophysics Data System (ADS)

    Samim, Masood

    A framework for the nonlinear optical polarimetry and polarimetric microscopy is developed. Mathematical equations are derived in terms of linear and nonlinear Stokes Mueller formalism, which comprehensively characterize the polarization properties of the incoming and outgoing radiations, and provide structural information about the organization of the investigated materials. The algebraic formalism developed in this thesis simplifies many predictions for a nonlinear polarimetry study and provides an intuitive understanding of various polarization properties for radiations and the intervening medium. For polarimetric microscopy experiments, a custom fast-scanning differential polarization microscope is developed, which is also capable of real-time three-dimensional imaging. The setup is equipped with a pair of high-speed resonant and galvanometric scanning mirrors, and supplemented by advanced adaptive optics and data acquisition modules. The scanning mirrors when combined with the adaptive optics deformable mirror enable fast 3D imaging. Deformable membrane mirrors and genetic algorithm optimization routines are employed to improve the imaging conditions including correcting the optical aberrations, maximizing signal intensities, and minimizing point-spread-functions of the focal volume. A field-programmable-gate array (FPGA) chip is exploited to rapidly acquire and process the multidimensional data. Using the nonlinear optical polarimetry framework and the home-built polarization microscope, a few biologically important tissues are measured and analyzed to gain insight as to their structure and dynamics. The structure and distribution of muscle sarcomere myosins, connective tissue collagen, carbohydrate-rich starch, and fruit fly eye retinal molecules are characterized with revealing polarization studies. In each case, using the theoretical framework, polarization sensitive data are analyzed to decipher the molecular orientations and nonlinear optical

  3. MCM Polarimetric Radiometers for Planar Arrays

    NASA Technical Reports Server (NTRS)

    Kangaslahti, Pekka; Dawson, Douglas; Gaier, Todd

    2007-01-01

    A polarimetric radiometer that operates at a frequency of 40 GHz has been designed and built as a prototype of multiple identical units that could be arranged in a planar array for scientific measurements. Such an array is planned for use in studying the cosmic microwave background (CMB). All of the subsystems and components of this polarimetric radiometer are integrated into a single multi-chip module (MCM) of substantially planar geometry. In comparison with traditional designs of polarimetric radiometers, the MCM design is expected to greatly reduce the cost per unit in an array of many such units. The design of the unit is dictated partly by a requirement, in the planned CMB application, to measure the Stokes parameters I, Q, and U of the CMB radiation with high sensitivity. (A complete definition of the Stokes parameters would exceed the scope of this article. In necessarily oversimplified terms, I is a measure of total intensity of radiation, while Q and U are measures of the relationships between the horizontally and vertically polarized components of radiation.) Because the sensitivity of a single polarimeter cannot be increased significantly, the only way to satisfy the high-sensitivity requirement is to make a large array of polarimeters that operate in parallel. The MCM includes contact pins that can be plugged into receptacles on a standard printed-circuit board (PCB). All of the required microwave functionality is implemented within the MCM; any required supporting non-microwave ("back-end") electronic functionality, including the provision of DC bias and control signals, can be implemented by standard PCB techniques. On the way from a microwave antenna to the MCM, the incoming microwave signal passes through an orthomode transducer (OMT), which splits the radiation into an h + i(nu) beam and an h - i(nu) beam (where, using complex-number notation, h denotes the horizontal component, nu denotes the vertical component, and +/-i denotes a +/-90deg phase

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. Detection of macroalgae blooms by complex SAR imagery.

    PubMed

    Shen, Hui; Perrie, William; Liu, Qingrong; He, Yijun

    2014-01-15

    Increased frequency and enhanced damage to the marine environment and to human society caused by green macroalgae blooms demand improved high-resolution early detection methods. Conventional satellite remote sensing methods via spectra radiometers do not work in cloud-covered areas, and therefore cannot meet these demands for operational applications. We present a methodology for green macroalgae bloom detection based on RADARSAT-2 synthetic aperture radar (SAR) images. Green macroalgae patches exhibit different polarimetric characteristics compared to the open ocean surface, in both the amplitude and phase domains of SAR-measured complex radar backscatter returns. In this study, new index factors are defined which have opposite signs in green macroalgae-covered areas, compared to the open water surface. These index factors enable unsupervised detection from SAR images, providing a high-resolution new tool for detection of green macroalgae blooms, which can potentially contribute to a better understanding of the mechanisms related to outbreaks of green macroalgae blooms in coastal areas throughout the world ocean.

  9. 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.

  10. Spaceborne Hybrid Quad-Pol SAR Range Ambiguity Analysis and Simulations

    NASA Astrophysics Data System (ADS)

    Yang, Shilin; Li, Yang; Zhang, Jingjing; Hong, Wen

    2014-11-01

    The higher levels of range ambiguities in the cross-polarized measurement channels are the primary limitations for the matched quad-pol (e.g., HH, VV, VH, and HV) spaceborne synthetic aperture radar (SAR) systems. These ambiguities severely constrain the useful range of incident angles and the swath widths particularly at larger incidence. Adopting hybridpolarimetric architecture can remarkably reduce these ambiguities. In this paper, we analyse and develop the expression of range ambiguity to signal ratio (RASR) in the hybrid-polarimetric architecture. Simulations are made to testify this novel architecture’s advantage in the improvement of range ambiguities. The system operating parameters are derived from NASA’s DESDynl mission. In addition, we used the second order moments of polarimetric covariance matrices to depict target or the environment which are more precisely.

  11. 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.

  12. 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.

  13. 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.

  14. Through-the-wall polarimetric imaging

    NASA Astrophysics Data System (ADS)

    Ahmad, Fauzia; Amin, Moeness G.

    2008-04-01

    Through-the-Wall Imaging is emerging as an affordable sensor technology supporting a variety of applications, such as surveillance and reconnaissance, emergency rescue, and firefighting. Motivated by the desire to understand the underlying phenomenology and performance bounds associated with imaging targets behind walls, several through-the-wall imaging experiments were conducted at the Center for Advanced Communications (CAC), Villanova University. These experiments aimed at supporting resolution, polarization, and localization of indoor targets and objects behind walls, and provided valuable dual-polarized synthetic aperture data measurements of indoor scenes of different complexity and population. In this paper, we present full-polarization imaging results, for a setting of calibrated reflectors behind a typical exterior grade wall. These imaging results provide polarimetric scene characterization and are shown to be in good agreement with the ground truth.

  15. Polarimetric characterization of birefringent filter components.

    PubMed

    Mudge, Jason; Mitchell, Keith; Tarbell, Theodore

    2015-01-10

    Over the past 75 years, birefringent filter technology has evolved significantly. For nearly that same period of time, these filters have been designed and used by solar scientists to study the Sun. Prior to assembling these types of filters, each component, e.g., polarizers and wave plates, is characterized to determine its polarimetric parameters to ensure the desired filter design performance. With time and cost becoming an ever increasing issue, it is imperative to test components designated for a birefringent filter efficiently. This article addresses a shift to increased efficiency when testing components of very low volume (<5 units) solar research filters that minimizes high-priced hardware expenditures, i.e., Mueller matrix spectropolarimeter. PMID:25967624

  16. 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.

  17. 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

  18. Detecting oil on water using polarimetric imaging

    NASA Astrophysics Data System (ADS)

    Iler, Amber L.; Hamilton, Patrick D.

    2015-05-01

    Integrity Applications Incorporated (IAI) collected electro-optical polarimetric imagery (PI) to evaluate its effectiveness for detecting oil on water. Data was gathered at multiple sun angles for vegetable oil and crude oil to demonstrate PI sensitivity to different liquids and collection geometries. Unique signatures for oil relative to water were observed. Both oils consistently displayed higher degree of linear polarization (DOLP) values than water, which was expected based on the lower index of refraction of water (1.33) relative to vegetable oil and crude oil (1.47 and 1.47-1.57, respectively). The strength of the polarimetric signatures was found to vary as a function of collection angle relative to the sun, with peak linear polarizations ranging from 40-70% for crude oil and 20-50% for vegetable oil. IAI found that independently scaled DOLP was particularly useful for discriminating these liquids, because it demonstrated the least sensitivity to collection angle, compared to other PI products. Specifically, the DOLP signature of vegetable oil was approximately 20% lower than for crude oil, regardless of collection angle. This finding is consistent with the lower index of refraction values for vegetable oil compared to crude. Based on the promising results presented here, IAI recommends further testing and development of PI for oceanic remote sensing applications such as oil spill/leak detection and for supporting oil cleanup efforts. With additional work, PI may also be applicable to other oceanic environmental issues such as detection of agricultural runoff or effluent from industrial facilities or watercraft.

  19. Digital Beamforming Synthetic Aperture Radar (DBSAR) Polarimetric Upgrade

    NASA Technical Reports Server (NTRS)

    Rincon, Rafael F.; Perrine, Martin; McLinden, Matthew; Valett, Susan

    2011-01-01

    The Digital Beamforming Synthetic Aperture Radar (DBSAR) is a state-of-the-art radar system developed at NASA/Goddard Space Flight Center for the development and implementation of digital beamforming radar techniques. DBSAR was recently upgraded to polarimetric operation in order to enhance its capability as a science instrument. Two polarimetric approaches were carried out which will be demonstrated in upcoming flight campaigns.

  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. TerraSAR-X dual-pol time-series for mapping of wetland vegetation

    NASA Astrophysics Data System (ADS)

    Betbeder, Julie; Rapinel, Sébastien; Corgne, Samuel; Pottier, Eric; Hubert-Moy, Laurence

    2015-09-01

    Mapping vegetation formations at a fine scale is crucial for assessing wetland functions and for better landscape management. Identification and characterization of vegetation formations is generally conducted at a fine scale using ecological ground surveys, which are limited to small areas. While optical remotely sensed imagery is limited to cloud-free periods, SAR time-series are used more extensively for wetland mapping and characterization using the relationship between distribution of vegetation formations and flood duration. The aim of this study was to determine the optimal number and key dates of SAR images to be classified to map wetland vegetation formations at a 1:10,000 scale. A series of eight dual-polarization TerraSAR-X images (HH/VV) was acquired in 2013 during dry and wet seasons in temperate climate conditions. One polarimetric parameter was extracted first, the Shannon entropy, which varies with wetland flooding status and vegetation roughness. Classification runs of all the possible combinations of SAR images using different k (number of images) subsets were performed to determine the best combinations of the Shannon entropy images to identify wetland vegetation formations. The classification runs were performed using Support Vector Machine techniques and were then analyzed using the McNemar test to investigate significant differences in the accuracy of all classification runs based on the different image subsets. The results highlight the relevant periods (i.e. late winter, spring and beginning of summer) for mapping vegetation formations, in accordance with ecological studies. They also indicate that a relationship can be established between vegetation formations and hydrodynamic processes with a short time-series of satellite images (i.e. 5 dates). This study introduces a new approach for herbaceous wetland monitoring using SAR polarimetric imagery. This approach estimates the number and key dates required for wetland management (e

  2. 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.

  3. The VAMPIRES instrument: imaging the innermost regions of protoplanetary discs with polarimetric interferometry

    NASA Astrophysics Data System (ADS)

    Norris, Barnaby; Schworer, Guillaume; Tuthill, Peter; Jovanovic, Nemanja; Guyon, Olivier; Stewart, Paul; Martinache, Frantz

    2015-03-01

    Direct imaging of protoplanetary discs promises to provide key insight into the complex sequence of processes by which planets are formed. However, imaging the innermost region of such discs (a zone critical to planet formation) is challenging for traditional observational techniques (such as near-IR imaging and coronagraphy) due to the relatively long wavelengths involved and the area occulted by the coronagraphic mask. Here, we introduce a new instrument - Visible Aperture-Masking Polarimetric Interferometer for Resolving Exoplanetary Signatures (VAMPIRES) - which combines non-redundant aperture-masking interferometry with differential polarimetry to directly image this previously inaccessible innermost region. By using the polarization of light scattered by dust in the disc to provide precise differential calibration of interferometric visibilities and closure phases, VAMPIRES allows direct imaging at and beyond the telescope diffraction limit. Integrated into the SCExAO (Subaru Coronagraphic Extreme Adaptive Optics) system at the Subaru telescope, VAMPIRES operates at visible wavelengths (where polarization is high) while allowing simultaneous infrared observations conducted by HICIAO. Here, we describe the instrumental design and unique observing technique and present the results of the first on-sky commissioning observations, validating the excellent visibility and closure-phase precision which are then used to project expected science performance metrics.

  4. 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

  5. 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.

  6. On-board Polarimetric Calibration of Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) Measurements

    NASA Astrophysics Data System (ADS)

    van Harten, G.; Diner, D. J.; Bull, M. A.; Tkatcheva, I. N.; Jovanovic, V. M.; Seidel, F. C.; Garay, M. J.; Xu, F.; Davis, A. B.; Rheingans, B. E.; Chipman, R. A.

    2015-12-01

    The Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) aims at characterizing atmospheric aerosols and clouds using highly accurate imaging polarimetry. The instrument is deployed regularly onboard the NASA ER2 high-altitude aircraft, which is an ideal testbed for satellite remote sensing. Flying at 20 km altitude, AirMSPI's pushbroom camera typically provides 11×11 km images at 10 m resolution. The target is observed from multiple along-track angles within ±67° using a gimbal mount. Eight spectral bands within 355-935 nm are recorded simultaneously in different detector rows, 3 of which also measure linear polarization: 470, 660 and 865 nm. Photoelastic modulators (PEMs) encode the polarized and total intensities in each polarimetric pixel as the amplitude and offset of a wavelike intensity pattern, such that the ratio of the two is insensitive to pixel-to-pixel differences. This enables an accuracy in the degree of linear polarization of ~0.001, as measured in the lab. To maintain this accuracy in-flight, an optical probe continuously monitors the PEMs' retardances and controls their driving signals. Before and after observing a target, the instrument also observes a validator, which is an extended, polarized light source, located inside the instrument housing. These data are now incorporated in the data processing pipeline to further improve the calibration of the modulation functions. Highly polarized pixels in Earth data are utilized to transfer the validator results to meet the illumination in Earth scenes, as well as to make fine adjustments at higher temporal resolution. The reprocessed polarization products for the PODEX campaign show significant improvements when intercompared with the Research Scanning Polarimeter (RSP, Goddard Institute for Space Studies). We currently evaluate the impact of the on-board polarimetric calibration on aerosol retrievals, and compare against AERONET reference measurements.

  7. Synthetic Aperture Radar (sar) Based Classifiers for Land Applications in Germany

    NASA Astrophysics Data System (ADS)

    Suresh, G.; Gehrke, R.; Wiatr, T.; Hovenbitzer, M.

    2016-06-01

    Land cover information is essential for urban planning and for land cover change monitoring. This paper presents an overview of the work conducted at the Federal Agency for Cartography and Geodesy (BKG) with respect to Synthetic Aperture Radar (SAR) based land cover classification. Two land cover classification approaches using SAR images are reported in this paper. The first method involves a rule-based classification using only SAR backscatter intensity while the other method involves supervised classification of a polarimetric composite of the same SAR image. The LBM-DE has been used for training and validation of the SAR classification results. Images acquired from the Sentinel-1a satellite are used for classification and the results have been reported and discussed. The availability of Sentinel-1a images that are weather and daylight independent allows for the creation of a land cover classification system that can be updated and validated periodically, and hence, be used to assist other land cover classification systems that use optical data. With the availability of Sentinel-2 data, land cover classification combining Sentinel-1a and Sentinel-2 images present a path for the future.

  8. 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.

  9. 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.

  10. Polarimetric Retrievals of Cloud Droplet Number Concentrations

    NASA Astrophysics Data System (ADS)

    Sinclair, K.; Cairns, B.; Hair, J. W.; Hu, Y.; Hostetler, C. A.

    2014-12-01

    Cloud droplet number concentration (CDNC) is one of the most significant microphysical properties of liquid clouds and is essential for the understanding of aerosol-cloud interaction. It impacts radiative forcing, cloud evolution, precipitation, global climate and, through observation, can be used to monitor the cloud albedo effect, or the first indirect effect. The IPCC's Fifth Assessment Report continues to consider aerosol-cloud interactions as one of the largest uncertainties in radiative forcing of climate. The SABOR experiment, which was a NASA-led ship and air campaign off the east coast of the United States during July and August of 2014, provided an opportunity for the Research Scanning Polarimeter (RSP) to develop and cross-validate a new approach of sensing CDNC with the High Spectral Resolution Lidar (HSRL). The RSP is an airborne prototype of the Aerosol Polarimetry Sensor (APS) that was on-board the Glory satellite. It is a scanning sensor that provides high-precision measurements of polarized and full-intensity radiances at multiple angles over a wide spectral range. The distinctive feature of the polarimetric technique is that it does not make any assumption of the liquid water profile within the cloud. The approach involves (1) estimating the droplet size distribution from polarized reflectance observations in the rainbow, (2) using polarized reflectance to estimate above cloud water vapor and total reflectance to find how much near infra-red light is being absorbed in clouds, (3) finding cloud physical thickness from the absorption and cloud top pressure retrievals assuming a saturated mixing ratio for water vapor and (4) determining the cloud droplet number concentration from the physical thickness and droplet size distribution retrievals. An overview of the polarimetric technique will be presented along with the results of applying the new approach to SABOR campaign data. An analysis of the algorithm's performance when compared with the HSRL

  11. X-Bragg Based Detection of Oil Spills Using Polarimetric SAR

    NASA Astrophysics Data System (ADS)

    Rudjord, Oystein; Salberg, Arnt-Borre

    2013-03-01

    It is possible to construct three features from the quad-pol coherency matrix of the X-Bragg scattering model, two that are independent of the relative permittivity, and one that is independent of the surface roughness. In this study we test these three features on Radarsat-2 and SIR-C data containing oil spill and look-alikes, in order to investigate the properties of these features for oil spill detection. We find that the features may distinguish oil from water, but are less sensitive to biogenic slicks and other look alikes. This useful for for operational oil spill detection.

  12. A new numerical method for calculating extrema of received power for polarimetric SAR

    USGS Publications Warehouse

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

    2009-01-01

    A numerical method called cross-step iteration is proposed to calculate the maximal/minimal received power for polarized imagery based on a target's Kennaugh matrix. This method is much more efficient than the systematic method, which searches for the extrema of received power by varying the polarization ellipse angles of receiving and transmitting polarizations. It is also more advantageous than the Schuler method, which has been adopted by the PolSARPro package, because the cross-step iteration method requires less computation time and can derive both the maximal and minimal received powers, whereas the Schuler method is designed to work out only the maximal received power. The analytical model of received-power optimization indicates that the first eigenvalue of the Kennaugh matrix is the supremum of the maximal received power. The difference between these two parameters reflects the depolarization effect of the target's backscattering, which might be useful for target discrimination. ?? 2009 IEEE.

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Multispectral polarimetric system for glucose monitoring

    NASA Astrophysics Data System (ADS)

    Cote, Gerard L.; Gorde, Harshal; Janda, Joseph; Cameron, Brent D.

    1998-05-01

    In this preliminary investigation, a two wavelength optical polarimetric system was used to show the potential of the approach to be used as an in vivo noninvasive glucose monitor. The dual wavelength method is shown as a means of overcoming two of them ore important problems with this approach for glucose monitoring, namely, motion artifact and the presence of other optically chiral components. The use of polarized light is based on the fact that the polarization vector of the light rotates when it interacts with an optically active material such as glucose. The amount of rotation of the light polarization is directly proportional to the optically active molecular concentration and to the sample path length. The end application of this system would be to estimate blood glucose concentrations indirectly by measuring the amount of rotation of the light beam's polarization state due to glucose variations within the aqueous humor of the anterior chamber of the eye. The system was evaluated in vitro in the presence of motion artifact and in combination with albumin, another interfering optical rotatory chemical component. It was shown that the dual wavelength approach has potential for overcoming these problems.

  6. Polarimetric Radar Observations of Hail Formation.

    NASA Astrophysics Data System (ADS)

    Kennedy, Patrick C.; Rutledge, Steven A.; Petersen, Walter A.; Bringi, V. N.

    2001-08-01

    Analyses are made of the evolution of selected polarimetric radar data fields during periods immediately preceding the onset of near-surface hail indicators [high reflectivity and low differential reflectivity (Zdr)] in two nonsupercellular northeastern Colorado hailstorms. The primary data were obtained from the 11-cm-wavelength, dual-polarization Colorado State University (CSU)-University of Chicago and Illinois State Water Survey radar. In one of the storms, dual-Doppler wind field syntheses were available using additional velocity data collected by the CSU Pawnee S-band radar. In both events, linear depolarization ratio (LDR) values exceeding 25 dB began to appear in the right flank of the 50-dBZ echo core region, within the 0° to 20°C environmental temperature range, approximately 10 minutes prior to the onset of hail at the surface. Scattering calculations suggest that the LDR enhancement may have been caused by an increasing water fraction within the growing hailstones (spongy hail), or the development of a liquid water coat under wet growth conditions. Vertical structure of the Zdr fields was also examined. As hypothesized by Conway and Zrni, it was found that the distinctness of the positive Zdr column associated with supercooled raindrops and incompletely frozen particles above the 0°C height varies from storm to storm.

  7. Polarimetric imaging and radiometry in shallow waters

    NASA Astrophysics Data System (ADS)

    Tonizzo, Alberto; Gilerson, Alexander; Carrizo, Carlos; Israel, Jean-Paul; Ahmed, Sam

    2012-06-01

    Imaging in scattering media with the purpose of object identification has always been a challenging task. In the ocean, and especially in coastal areas, the situation is one of the worst: absorption and scattering by suspended and dissolved particles take away most of the information and blur the image of the target to be identified. In addition, one has also to take into account the variability of the bottom which, being close to the surface, plays an important role in the resulting integrated light field. Our goal in this study is to gain insight into the effects of the variable environments on the complex polarized underwater realm. We analyze the polarized tridimensional underwater environment. The instruments deployed were an underwater hyperspectral and multi-angular polarimeter, whose accuracy and exactness of results have been previously validated by the means of different radiative transfer calculations; and a green band full-Stokes polarimetric video camera, enclosed in a custom made underwater housing. The results presented here were collected during the first field deployment of the imaging camera. An in-situ validation of the camera with the polarimeter has been obtained and the results have been used to validate the values of the Stokes elements in the images, both for the water column itself and for the underlying bottom.

  8. 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.

  9. 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

  10. 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.

  11. Polarimetric assist to HSI atmospheric compensation and material identification

    NASA Astrophysics Data System (ADS)

    Gibney, Mark

    2016-05-01

    In this effort, we investigated how polarimetric HyperSpectral Imaging (pHSI) data might benefit specified Material Identification of diffuse materials in the VNIR. The experiment compared paint reflectivities extracted from polarimetric hyperspectral data acquired in the field to a database of truth reflectivities measured in the lab. Both the polarimetric hyperspectral data and the reflectivities were acquired using an Ocean Optics spectrometer which was polarized using a fast filter wheel loaded with high extinction polarizers. During the experiment, we discovered that the polarized spectra from the polarimetric hyper spectral data could be used to estimate the relative spectral character of the field source (the exo-atmospheric sun plus the atmosphere). This benefit, which strongly parallels the QUAC atmospheric correction method, relies on the natural spectral flatness of the polarized spectrum that originates in the spectral flatness of the index of refraction in the reflective regime. Using this estimate of the field source, excellent estimates of the paint reflectivities (matching 10 paint reflectivities to <= 0.5% RSS) were obtained. The impact of atmospheric upwell on performance was then investigated using these ground based polarimetric hyper spectral data in conjunction with modeled atmospheric path effects. The path effects were modeled using the high fidelity Polarimetry Phenomenology Simulation (PPS) plate model developed by AFRL, which includes polarized Modtran. We conclude with a discussion of actual and potential applications of this method, and how best to convert an existing VNIR HSI sensor into a pHSI sensor for an airborne Proof Of Concept experiment.

  12. On the eigenvalue analysis using HH-VV dual-polarization SAR data and its applications to monitoring of coastal oceans

    NASA Astrophysics Data System (ADS)

    Sugimoto, Mitsunobu; Ouchi, Kazuo; Yang, Chan-Su

    2013-06-01

    In the conventional SAR (Synthetic Aperture Radar) polarimetry, fully polarimetric HH-HV-VH-VV quad polarization data are used. The advantage of using quad-polarization data is more information on the scattering objects than the single- and quad-polarization data; while the disadvantages are narrower swath and less frequent data takes. To fill the gap in-between, the present study examines the polarimetric analysis using HH-VV dual polarization. The model-based three- and four-component scattering power decomposition analyses are not possible with dual-polarization data, and thus, the study is focused on the eigenvalue decomposition analysis by comparing the entropy and mean alpha angle derived from dual-polarization data with those derived from quad polarization data, acquired by ALOS-PALSAR (Advanced Land Observing Satellite Phased Array L-band SAR) PLR (PoLaRimetric mode) and TerraSAR-X dual-polarization SpotLight mode over the Tokyo Bay, Japan. The preliminary results indicate that the values of dual-polarization entropy and alpha angle are almost the same as the quad-polarization values, indicating that dual-polarization data are as capable as quad-polarization data in the eigenvalue decomposition. The technique is then applied to estimating the underwater laver cultivation fields and ship detection.

  13. The classification of ambiguity in polarimetric reconstruction of coronal mass ejection

    SciTech Connect

    Dai, Xinghua; Wang, Huaning; Huang, Xin; Du, Zhanle; He, Han

    2014-01-10

    The Thomson scattering theory indicates that there exist explicit and implicit ambiguities in polarimetric analyses of coronal mass ejection (CME) observations. We suggest a classification for these ambiguities in CME reconstruction. Three samples, including double explicit, mixed, and double implicit ambiguity, are shown with the polarimetric analyses of STEREO CME observations. These samples demonstrate that this classification is helpful for improving polarimetric reconstruction.

  14. 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.

  15. 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

  16. 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.

  17. Enhancing the Accessibility and Utility of UAVSAR L-band SAR Data

    NASA Astrophysics Data System (ADS)

    Atwood, D.; Arko, S. A.; Gens, R.; Sanches, R. R.

    2011-12-01

    The UAVSAR instrument, developed at NASA Jet Propulsion Lab, is a reconfigurable L-band, quad-polarimetric Synthetic Aperture Radar (SAR) developed specifically for repeat-track differential interferometry (InSAR). It offers resolution of approximately 5m and swaths greater than 16 km. Although designed to be flown aboard a UAV (Uninhabited Aerial Vehicle), it is currently being flown aboard a Gulfstream III in an ambitious set of campaigns around the world. The current archive from 2009 contains data from more than 100 missions from North America, Central America, the Caribbean, and Greenland. Compared with most SAR data from satellites, UAVSAR offers higher resolution, full-polarimetry, and an impressive noise floor. For scientists, these datasets present wonderful opportunities for understanding Earth processes and developing new algorithms for information extraction. Yet despite the diverse range of coverage, UAVSAR is still relatively under-utilized. In its capacity as the NASA SAR DAAC, the Alaska Satellite Facility (ASF) is interested in expanding recognition of this data and serving data products that can be readily downloaded into a Geographic Information System (GIS) environment. Two hurdles exist: one is the large size of the data products and the second is the format of the data. The data volumes are in excess of several GB; presenting slow downloads and overwhelming many software programs. Secondly, while the data is appropriately formatted for expert users, it may prove challenging for scientists who have not previously worked with SAR. This paper will address ways that ASF is working to reduce data volume while maintaining the integrity of the data. At the same time, the creation of value-added products that permit immediate visualization in a GIS environment will be described. Conversion of the UAVSAR polarimetric data to radiometrically terrain-corrected Pauli images in a GeoTIFF format will permit researchers to understand the scattering

  18. Narrow band 3 × 3 Mueller polarimetric endoscopy

    PubMed Central

    Qi, Ji; Ye, Menglong; Singh, Mohan; Clancy, Neil T.; Elson, Daniel S.

    2013-01-01

    Mueller matrix polarimetric imaging has shown potential in tissue diagnosis but is challenging to implement endoscopically. In this work, a narrow band 3 × 3 Mueller matrix polarimetric endoscope was designed by rotating the endoscope to generate 0°, 45° and 90° linearly polarized illumination and positioning a rotating filter wheel in front of the camera containing three polarisers to permit polarization state analysis for backscattered light. The system was validated with a rotating linear polarizer and a diffuse reflection target. Initial measurements of 3 × 3 Mueller matrices on a rat are demonstrated, followed by matrix decomposition into the depolarization and retardance matrices for further analysis. Our work shows the feasibility of implementing polarimetric imaging in a rigid endoscope conveniently and economically in order to reveal diagnostic information. PMID:24298405

  19. A new polarimetric active radar calibrator and calibration technique

    NASA Astrophysics Data System (ADS)

    Tang, Jianguo; Xu, Xiaojian

    2015-10-01

    Polarimetric active radar calibrator (PARC) is one of the most important calibrators with high radar cross section (RCS) for polarimetry measurement. In this paper, a new double-antenna polarimetric active radar calibrator (DPARC) is proposed, which consists of two rotatable antennas with wideband electromagnetic polarization filters (EMPF) to achieve lower cross-polarization for transmission and reception. With two antennas which are rotatable around the radar line of sight (LOS), the DPARC provides a variety of standard polarimetric scattering matrices (PSM) through the rotation combination of receiving and transmitting polarization, which are useful for polarimatric calibration in different applications. In addition, a technique based on Fourier analysis is proposed for calibration processing. Numerical simulation results are presented to demonstrate the superior performance of the proposed DPARC and processing technique.

  20. Radiative transfer theory for polarimetric remote sensing of pine forest

    NASA Technical Reports Server (NTRS)

    Hsu, C. C.; Han, H. C.; Shin, Robert T.; Kong, Jin AU; Beaudoin, A.; Letoan, T.

    1992-01-01

    The radiative transfer theory is applied to interpret polarimetric radar backscatter from pine forest with clustered vegetation structures. To take into account the clustered structures with the radiative transfer theory, the scattering function of each cluster is calculated by incorporating the phase interference of scattered fields from each component. Subsequently, the resulting phase matrix is used in the radiative transfer equations to evaluate the polarimetric backscattering coefficients from random medium layers embedded with vegetation clusters. Upon including the multi-scale structures, namely, trunks, primary and secondary branches, as well as needles, we interpret and simulate the polarimetric radar responses from pine forest for different frequencies and looking angles. The preliminary results are shown to be in good agreement with the measured backscattering coefficients at the Landes maritime pine forest during the MAESTRO-1 experiment.

  1. Radiative transfer theory for polarimetric remote sensing of pine forest

    NASA Technical Reports Server (NTRS)

    Hsu, C. C.; Han, H. C.; Shin, R. T.; Kong, J. A.; Beaudoin, A.; Le Toan, T.

    1992-01-01

    The radiative transfer theory is applied to interpret polarimetric radar backscatter from pine forest with clustered vegetation structures. The scattering function of each cluster is calculated by incorporating the phase interference of scattered fields from each component. The resulting phase matrix is used in the radiative transfer equations to evaluate the polarimetric backscattering coefficients from random medium layers embedded with vegetation clusters. Upon including multiscale structures (trunks, primary and secondary branches, and needles), polarimetric radar responses from pine forest for different frequencies and looking angles are interpreted and simulated. Preliminary results are shown to be in good agreement with the measured backscattering coefficients at the Landes maritime pine forest during the MAESTRO-1 experiment.

  2. The Next Generation Airborne Polarimetric Doppler Radar

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  3. Polarimetric thermal emission from periodic water surfaces

    NASA Technical Reports Server (NTRS)

    Yueh, S. H.; Nghiem, S. V.; Kwok, R.; Wilson, W. J.; Li, F. K.; Johnson, J. T.; Kong, J. A.

    1993-01-01

    Experimental results and theoretical calculations are presented to study the polarimetric emission from water surfaces with directional features. For our ground-based Ku-band radiometer measurements, a water pool was constructed on the roof of a building in the Jet Propulsion Laboratory, and a fiberglass surface with periodic corrugations in one direction was impressed on the top of the water surface to create a stationary water surface underneath it. It is observed that the measured Stokes parameters of corrugated fiberglass-covered water surfaces are functions of azimuth angles and agree very well with the theoretical calculations. The theory, after being verified by the experimental data, was then used to calculate the Stokes parameters of periodic surfaces without fiberglass surface layer and with rms height of the order of wind-generated water ripples. The magnitudes of the azimuthal variation of the calculated emissivities at horizontal and vertical polarizations corresponding to the first two Stokes parameters are found to be comparable to the values measured by airborne radiometers and SSM/I. In addition, the third Stokes parameter not shown in the literature is seen to have approximately twice the magnitude of the azimuth variation of either T(sub h) or T(sub v), which may make it more sensitive to the row direction, while less susceptive to noises because the atmospheric and system noises tend to be unpolarized and are expected to be cancelled out when the third Stokes parameter is derived as the difference of two or three power measurements, as indicated by another experiment carried out at a swimming pool with complicated surroundings. The results indicate that passive polarimetry is a potential technology in the remote sensing of ocean wind vector which is a crucial component in the understanding of global climate change. Issues related to the application of microwave passive polarimetry to ocean wind are also discussed.

  4. 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.

  5. 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.

  6. The X-ray polarimetric view of astrophysical black holes

    NASA Astrophysics Data System (ADS)

    Matt, Giorgio

    2016-07-01

    Our current X-ray view of astrophysical black holes is based on spectroscopic, imaging and timing analysis. In this talk I will discuss the importance of adding the polarimetric view. The geometry of the X-ray emitting corona, the distribution of accreting matter, the magnetic field in jets and even the space-time close to the event horizon can be probed by X-ray polarimetry. I will also discuss the observational perspectives in view of the X-ray polarimetric missions currently under study at NASA and ESA.

  7. Snapshot spectral and polarimetric imaging; target identification with multispectral video

    NASA Astrophysics Data System (ADS)

    Bartlett, Brent D.; Rodriguez, Mikel D.

    2013-05-01

    As the number of pixels continue to grow in consumer and scientific imaging devices, it has become feasible to collect the incident light field. In this paper, an imaging device developed around light field imaging is used to collect multispectral and polarimetric imagery in a snapshot fashion. The sensor is described and a video data set is shown highlighting the advantage of snapshot spectral imaging. Several novel computer vision approaches are applied to the video cubes to perform scene characterization and target identification. It is shown how the addition of spectral and polarimetric data to the video stream allows for multi-target identification and tracking not possible with traditional RGB video collection.

  8. 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

  9. 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.

  10. Classification of Forest Regrowth Stage using Polarimetric Decomposition and Foliage Projective Cover

    NASA Astrophysics Data System (ADS)

    Clewley, D.; Lucas, R.; Bunting, P.; Moghaddam, M.

    2012-12-01

    Within Queensland, Australia extensive clearing of vegetation for agriculture has occurred within the Brigalow Belt Bioregion (BBB), reducing forests dominated by Acacia harpophylla (brigalow) to 10 % of their former extent. Where cleared land is left abandoned or unmanaged regeneration is rapid, Regenerating vegetation represents a more efficient and cost effective method for carbon sequestration than direct planting and offers a number of benefits over plantation forest, particularly in terms of provision of habitat for native fauna. To effectively protect regenerating vegetation, maps of the distribution of forests at different stages of regeneration are required. Whilst mapping approaches have traditionally focused on optical data, the high canopy cover of brigalow regrowth in all but the very early stages limits discrimination of forests at different stages of growth. The combination of optical data, namely Landsat derived Foliage Projective Cover (FPC) and Advanced Land Observing Satellite (ALOS) Phased Array L-band Synthetic Aperture Radar (SAR) backscatter data have previously been investigated for mapping regrowth. This study therefore aimed to investigate the potential of the alpha-Entropy (α/H) decomposition (S Cloude and E Pottier, "An entropy based classification scheme for land applications of polarimetric SAR," 1997, IEEE Transactions on Geoscience and Remote Sensing, vol. 35, no. 1, pp. 68-78) applied to polarimetric ALOS PALSAR backscatter for mapping regrowth stage combined with FPC data to account for canopy variations. The study focused on the Tara Downs subregion, located in the Western Darling Downs, within the south of the BBB. PALSAR data were acquired over the study site in fully-polarimetric mode (incidence angle mid swath ~ 26 degrees). From these data α/H layers were generated and stacked with FPC data. Considering only those areas known to contain brigalow prior to clearing and with an FPC > 9 %, k-means clustering was applied, with

  11. 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

  12. Anisotropy of seasonal snow measured by polarimetric phase differences in radar time series

    NASA Astrophysics Data System (ADS)

    Leinss, S.; Löwe, H.; Proksch, M.; Lemmetyinen, J.; Wiesmann, A.; Hajnsek, I.

    2015-11-01