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BACK TO INDEX Publications of year 2010 Articles in journal or book chapters
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| Abstract: | The propagation of spaceborne radar signals operating at L-band frequency or below can be seriously affected by the ionosphere. At high states of solar activity, Faraday rotation (FR) and signal path delays disturb radar polarimetry and reduce resolution in range and azimuth. While these effects are negligible at X-band, FR and the frequency-dependent path delays can become seriously problematic starting at L-band. For quality assurance and calibration purposes, existing L-band or potential spaceborne P-band missions require the estimation of the ionospheric state before or during the data take. This paper introduces two approaches for measuring the ionospheric total electron content (TEC) from single-polarized spaceborne SAR data. The two methods are demonstrated using simulations. Both methods leverage knowledge of the frequency-dependent path delay through the ionosphere: The first estimates TEC from the phase error of the filter mismatch, while the second gauges path-delay differences between up and down chirps. FR, mean (direct current) offsets, and noise contributions are also considered in the simulations. Finally, possibilities for further methodological improvements are discussed. |
@ARTICLE{jehleFreySmallMeier2010:IonTECfromSAR,
author = {Jehle, Michael and Frey, Othmar and Small, David and Meier, Erich},
title = {Measurement of Ionospheric {TEC} in Spaceborne {SAR} Data},
journal = {{IEEE} Trans. Geosci. Remote Sens.},
year = {2010},
volume = {48},
pages = {2460-2468},
number = {6},
month = jun,
abstract = {The propagation of spaceborne radar signals operating at L-band frequency or below can be seriously affected by the ionosphere. At high states of solar activity, Faraday rotation (FR) and signal path delays disturb radar polarimetry and reduce resolution in range and azimuth. While these effects are negligible at X-band, FR and the frequency-dependent path delays can become seriously problematic starting at L-band. For quality assurance and calibration purposes, existing L-band or potential spaceborne P-band missions require the estimation of the ionospheric state before or during the data take. This paper introduces two approaches for measuring the ionospheric total electron content (TEC) from single-polarized spaceborne SAR data. The two methods are demonstrated using simulations. Both methods leverage knowledge of the frequency-dependent path delay through the ionosphere: The first estimates TEC from the phase error of the filter mismatch, while the second gauges path-delay differences between up and down chirps. FR, mean (direct current) offsets, and noise contributions are also considered in the simulations. Finally, possibilities for further methodological improvements are discussed.},
doi = {10.1109/TGRS.2010.2040621},
issn = {0196-2892},
keywords = {SAR Processing, Total Electron Content Estimation, TEC Estimation, Ionospheric TEC, Faraday Rotation, Path Delay, Autofocus, TEC Autofocus, Spaceborne SAR, L-Band, ALOS, Phased Array L-band SAR,PALSAR, P-Pand, Simulation, Calibration},
owner = {ofrey},
pdf = {http://www.geo.uzh.ch/~ofrey/myPublications/PAPERS/jehleFreySmallMeier2010.pdf},
url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5427043}
}
Keywords: Tandem-L, Tandem-X, Formation Flying, Spaceborne SAR.
| Abstract: | This paper presents an overview of single-pass interferometric Synthetic Aperture Radar (SAR) missions employing two or more satellites flying in a close formation. The simultaneous reception of the scattered radar echoes from different viewing directions by multiple spatially distributed antennas enables the acquisition of unique Earth observation products for environmental and climate monitoring. After a short introduction to the basic principles and applications of SAR interferometry, designs for the twin satellite missions TanDEM-X and Tandem-L are presented. The primary objective of TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) is the generation of a global Digital Elevation Model (DEM) with unprecedented accuracy as the basis for a wide range of scientific research as well as for commercial DEM production. This goal is achieved by enhancing the TerraSAR-X mission with a second TerraSAR-X like satellite that will be launched in spring 2010. Both satellites act then as a large single-pass SAR interferometer with the opportunity for flexible baseline selection. Building upon the experience gathered with the TanDEM-X mission design, the fully polarimetric L-band twin satellite formation Tandem-L is proposed. Important objectives of this highly capable interferometric SAR mission are the global acquisition of three-dimensional forest structure and biomass inventories, large-scale measurements of millimetric displacements due to tectonic shifts, and systematic observations of glacier movements. The sophisticated mission concept and the high data-acquisition capacity of Tandem-L will moreover provide a unique data source to systematically observe, analyze, and quantify the dynamics of a wide range of additional processes in the bio-, litho-, hydro-, and cryosphere. By this, Tandem-L will be an essential step to advance our understanding of the Earth system and its intricate dynamics. Enabling technologies and techniques are described in detail. An ou- tlook on future interferometric and tomographic concepts and developments, including multistatic SAR systems with multiple receivers, is provided. |
@ARTICLE{KriegerHajnsekPapathanassiouYounisMoreira2010:FormationFlyingSpaceborneMissions,
author={Krieger, G. and Hajnsek, I. and Papathanassiou, K. P. and Younis, M. and Moreira, A.},
journal={Proceedings of the IEEE},
title={Interferometric Synthetic Aperture Radar ({SAR}) Missions Employing Formation Flying},
year={2010},
month=may,
volume={98},
number={5},
pages={816-843},
abstract={This paper presents an overview of single-pass interferometric Synthetic Aperture Radar (SAR) missions employing two or more satellites flying in a close formation. The simultaneous reception of the scattered radar echoes from different viewing directions by multiple spatially distributed antennas enables the acquisition of unique Earth observation products for environmental and climate monitoring. After a short introduction to the basic principles and applications of SAR interferometry, designs for the twin satellite missions TanDEM-X and Tandem-L are presented. The primary objective of TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) is the generation of a global Digital Elevation Model (DEM) with unprecedented accuracy as the basis for a wide range of scientific research as well as for commercial DEM production. This goal is achieved by enhancing the TerraSAR-X mission with a second TerraSAR-X like satellite that will be launched in spring 2010. Both satellites act then as a large single-pass SAR interferometer with the opportunity for flexible baseline selection. Building upon the experience gathered with the TanDEM-X mission design, the fully polarimetric L-band twin satellite formation Tandem-L is proposed. Important objectives of this highly capable interferometric SAR mission are the global acquisition of three-dimensional forest structure and biomass inventories, large-scale measurements of millimetric displacements due to tectonic shifts, and systematic observations of glacier movements. The sophisticated mission concept and the high data-acquisition capacity of Tandem-L will moreover provide a unique data source to systematically observe, analyze, and quantify the dynamics of a wide range of additional processes in the bio-, litho-, hydro-, and cryosphere. By this, Tandem-L will be an essential step to advance our understanding of the Earth system and its intricate dynamics. Enabling technologies and techniques are described in detail. An ou- tlook on future interferometric and tomographic concepts and developments, including multistatic SAR systems with multiple receivers, is provided.},
keywords={Tandem-L, Tandem-X, Formation Flying, Spaceborne SAR},
doi={10.1109/JPROC.2009.2038948},
ISSN={0018-9219},
}
Keywords: SAR Processing, InSAR, SAR Interferometry, ENVISAR, ASAR.
| Abstract: | This letter focuses on estimating the local fringe frequency of the interferometric phase, under the hypothesis of superficial scattering. Starting from the formulation of the maximum-likelihood estimator, a new simplified estimator is derived. Due to computational efficiency and robustness versus model errors, the resulting estimator is suited for large data processing in the presence of model uncertainty. Furthermore, such an estimator can be straightforwardly extended to the multibaseline case, resulting in the possibility to estimate the terrain slope with great accuracy. An application to real data is presented, based on a multibaseline ENVISAT data set. |
@ARTICLE{montiGuarnieriTebaldiniGRSL2010:InSARFringeFreqEstim,
author = {Monti-Guarnieri, Andrea and Tebaldini, Stefano},
title = {ML-Based Fringe-Frequency Estimation for InSAR},
journal = {IEEE Geoscience and Remote Sensing Letters},
year = {2010},
volume = {7},
pages = {136-140},
number = {1},
month = {jan},
abstract = {This letter focuses on estimating the local fringe frequency of the interferometric phase, under the hypothesis of superficial scattering. Starting from the formulation of the maximum-likelihood estimator, a new simplified estimator is derived. Due to computational efficiency and robustness versus model errors, the resulting estimator is suited for large data processing in the presence of model uncertainty. Furthermore, such an estimator can be straightforwardly extended to the multibaseline case, resulting in the possibility to estimate the terrain slope with great accuracy. An application to real data is presented, based on a multibaseline ENVISAT data set.},
doi = {10.1109/LGRS.2009.2028661},
issn = {1545-598X},
keywords = {SAR Processing, InSAR, SAR Interferometry, ENVISAR, ASAR},
owner = {ofrey},
pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/montiGuarnieriTebaldiniGRSL2010.pdf},
url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5238604&isnumber=5379155}
}
Keywords: SAR Processing, Bistatic SAR, Doppler information, German Aerospace Center, TerraSAR-X/F-SAR bistatic data, backscatter, bistatic backprojection algorithm, bistatic synthetic aperture radar, calibration, data processing, first X-band spaceborne-airborne SAR, nonstationary bistatic acquisitions, phase-preserving bistatic focusing, synchronization algorithm, airborne radar, backscatter, calibration, data acquisition, geophysical signal processing, radar signal processing, remote sensing by radar, spaceborne radar, synchronisation, synthetic aperture radar;.
| Abstract: | We report about the first X-band spaceborne-airborne bistatic synthetic aperture radar (SAR) experiment, conducted early November 2007, using the German satellite TerraSAR-X as transmitter and the German Aerospace Center's (DLR) new airborne radar system F-SAR as receiver. The importance of the experiment resides in both its pioneering character and its potential to serve as a test bed for the validation of nonstationary bistatic acquisitions, novel calibration and synchronization algorithms, and advanced imaging techniques. Due to the independent operation of the transmitter and receiver, an accurate synchronization procedure was needed during processing to make high-resolution imaging feasible. Precise phase-preserving bistatic focusing can only be achieved if time and phase synchronization exist. The synchronization approach, based on the evaluation of the range histories of several reference targets, was verified through a separate analysis of the range and Doppler contributions. After successful synchronization, nonstationary focusing was performed using a bistatic backprojection algorithm. During the campaign, stand-alone TerraSAR-X monostatic as well as interoperated TerraSAR-X/F-SAR bistatic data sets were recorded. As expected, the bistatic image shows a space-variant behavior in spatial resolution and in signal-to-noise ratio. Due to the selected configuration, the bistatic image outperforms its monostatic counterpart in almost the complete imaged scene. A detailed comparison between monostatic and bistatic images is given, illustrating the complementarity of both measurements in terms of backscatter and Doppler information. The results are of fundamental importance for the development of future nonsynchronized bistatic SAR systems. |
@ARTICLE{RodriguezCassolaBaumgartnerKriegerMoreira2007:BiStaticBackProjection,
author={Rodriguez-Cassola, M. and Baumgartner, S.V. and Krieger, G. and Moreira, A.},
journal=IEEE_J_GRS,
title={Bistatic {TerraSAR-X/F-SAR} Spaceborne-Airborne {SAR} Experiment: Description, Data Processing, and Results},
year={2010},
month=feb,
volume={48},
number={2},
pages={781-794},
abstract={We report about the first X-band spaceborne-airborne bistatic synthetic aperture radar (SAR) experiment, conducted early November 2007, using the German satellite TerraSAR-X as transmitter and the German Aerospace Center's (DLR) new airborne radar system F-SAR as receiver. The importance of the experiment resides in both its pioneering character and its potential to serve as a test bed for the validation of nonstationary bistatic acquisitions, novel calibration and synchronization algorithms, and advanced imaging techniques. Due to the independent operation of the transmitter and receiver, an accurate synchronization procedure was needed during processing to make high-resolution imaging feasible. Precise phase-preserving bistatic focusing can only be achieved if time and phase synchronization exist. The synchronization approach, based on the evaluation of the range histories of several reference targets, was verified through a separate analysis of the range and Doppler contributions. After successful synchronization, nonstationary focusing was performed using a bistatic backprojection algorithm. During the campaign, stand-alone TerraSAR-X monostatic as well as interoperated TerraSAR-X/F-SAR bistatic data sets were recorded. As expected, the bistatic image shows a space-variant behavior in spatial resolution and in signal-to-noise ratio. Due to the selected configuration, the bistatic image outperforms its monostatic counterpart in almost the complete imaged scene. A detailed comparison between monostatic and bistatic images is given, illustrating the complementarity of both measurements in terms of backscatter and Doppler information. The results are of fundamental importance for the development of future nonsynchronized bistatic SAR systems.},
keywords={SAR Processing,Bistatic SAR,Doppler information;German Aerospace Center;TerraSAR-X/F-SAR bistatic data;backscatter;bistatic backprojection algorithm;bistatic synthetic aperture radar;calibration;data processing;first X-band spaceborne-airborne SAR;nonstationary bistatic acquisitions;phase-preserving bistatic focusing;synchronization algorithm;airborne radar;backscatter;calibration;data acquisition;geophysical signal processing;radar signal processing;remote sensing by radar;spaceborne radar;synchronisation;synthetic aperture radar;},
doi={10.1109/TGRS.2009.2029984},
ISSN={0196-2892},
}
Keywords: SAR Processing, Bistatic SAR, BiSAR data, Forschungsgesellschaft fur Angewandte Naturwissenschaften, PAMIR, Transall C-160, airborne SAR system, azimuth modulation, bistatic SAR airborne-stationary configuration, bistatic SAR data, bistatic point-target reference spectrum, frequency domain based focusing algorithm, interpolation free wavenumber domain algorithm, range offset, range variant interpolation, stationary X-band transmitter, synthetic aperture radar, target azimuth position, target range migration trajectory, airborne radar, geophysical signal processing, interpolation, radar signal processing, remote sensing by radar, synthetic aperture radar;.
| Abstract: | This paper presents a frequency-domain-based focusing algorithm for the bistatic synthetic aperture radar (BiSAR) data in airborne/stationary configuration. In this bistatic configuration, only the moving platform contributes to the azimuth modulation, whereas the stationary platform introduces a range offset (RO) to the range migration trajectories of targets at the same range. The offset is determined by the azimuth position of different targets with respect to the stationary platform. Since the RO is position dependent, monostatic SAR imaging algorithms are not able to focus the bistatic data collected in this configuration. In this paper, an analytical bistatic point-target reference spectrum is derived, and then, a frequency-domain-based algorithm is developed to focus the bistatic data. It uses an interpolation-free wavenumber-domain algorithm as a basis and performs a range-variant interpolation to correct the position-dependent RO in the image domain after coarse focusing. The proposed algorithm is validated by the simulated data and the real BiSAR data acquired by the Forschungsgesellschaft fU¿r Angewandte Naturwissenschaften's airborne SAR system, PAMIR, in December 2007. In this BiSAR experiment, an X-band transmitter was stationary operated on a hill with PAMIR as the receiver mounted on a Transall C-160. |
@ARTICLE{WangLoffeldNeoNiesWalterscheidEspeterKlareEnder2010:BiStatic,
author={Wang, R. and Loffeld, O. and Neo, Y.L. and Nies, H. and Walterscheid, I. and Espeter, T. and Klare, J. and Ender, J.},
journal=IEEE_J_GRS,
title={Focusing Bistatic {SAR} Data in Airborne/Stationary Configuration},
year={2010},
month=jan,
volume={48},
number={1},
pages={452-465},
abstract={This paper presents a frequency-domain-based focusing algorithm for the bistatic synthetic aperture radar (BiSAR) data in airborne/stationary configuration. In this bistatic configuration, only the moving platform contributes to the azimuth modulation, whereas the stationary platform introduces a range offset (RO) to the range migration trajectories of targets at the same range. The offset is determined by the azimuth position of different targets with respect to the stationary platform. Since the RO is position dependent, monostatic SAR imaging algorithms are not able to focus the bistatic data collected in this configuration. In this paper, an analytical bistatic point-target reference spectrum is derived, and then, a frequency-domain-based algorithm is developed to focus the bistatic data. It uses an interpolation-free wavenumber-domain algorithm as a basis and performs a range-variant interpolation to correct the position-dependent RO in the image domain after coarse focusing. The proposed algorithm is validated by the simulated data and the real BiSAR data acquired by the Forschungsgesellschaft fU¿r Angewandte Naturwissenschaften's airborne SAR system, PAMIR, in December 2007. In this BiSAR experiment, an X-band transmitter was stationary operated on a hill with PAMIR as the receiver mounted on a Transall C-160.},
keywords={SAR Processing,Bistatic SAR,BiSAR data;Forschungsgesellschaft fur Angewandte Naturwissenschaften;PAMIR;Transall C-160;airborne SAR system;azimuth modulation;bistatic SAR airborne-stationary configuration;bistatic SAR data;bistatic point-target reference spectrum;frequency domain based focusing algorithm;interpolation free wavenumber domain algorithm;range offset;range variant interpolation;stationary X-band transmitter;synthetic aperture radar;target azimuth position;target range migration trajectory;airborne radar;geophysical signal processing;interpolation;radar signal processing;remote sensing by radar;synthetic aperture radar;},
doi={10.1109/TGRS.2009.2027700},
ISSN={0196-2892},
}
Conference articles
-
LeRoy A. Gorham and Brian D. Rigling.
Dual format algorithm for monostatic SAR.
In Edmund G. Zelnio and Frederick D. Garber, editors,
,
volume 7699,
pages 769905,
2010.
SPIE.
Keywords: SAR Processing, Dual Format Algorithm, DFA, Polar Format Algorithm, PFA, Spotlight SAR, Spotlight-mode data.@conference{gorhamRiglingDualFormatAlgorithm2010, author = {LeRoy A. Gorham and Brian D. Rigling}, editor = {Edmund G. Zelnio and Frederick D. Garber}, collaboration = {}, title = {Dual format algorithm for monostatic SAR}, publisher = {SPIE}, year = {2010}, journal = {Algorithms for Synthetic Aperture Radar Imagery XVII}, volume = {7699}, number = {1}, eid = {769905}, numpages = {6}, pages = {769905}, location = {Orlando, Florida, USA}, url = {http://link.aip.org/link/?PSI/7699/769905/1}, doi = {10.1117/12.855374}, keywords = {SAR Processing, Dual Format Algorithm, DFA, Polar Format Algorithm, PFA, Spotlight SAR, Spotlight-mode data}, pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/jakowatzWahlYockyBrayBowRichardsSpotlightComparisonOfAlgorithms2004.pdf}, owner = {ofrey}, } -
Charles V. Jakowatz,
Daniel E. Wahl,
and David A. Yocky.
A beamforming algorithm for bistatic SAR image formation.
In Edmund G. Zelnio and Frederick D. Garber, editors,
,
volume 7699,
pages 769902,
2010.
SPIE.
Keywords: SAR Processing, Bistatic SAR, Bistatic Spotlight-mode SAR, Autofocus, Autofocus in the TDBP Framework, Back-projection, Time-Domain Back-Projection, TDBP, Fast Back-projection, Fast-Factorized Back-Projection, FFBP, Spotlight SAR, Spotlight-mode data, Beamforming.@conference{jakowatzWahlYockyBeamformingBistatic2010, author = {Charles V. Jakowatz, Jr. and Daniel E. Wahl and David A. Yocky}, editor = {Edmund G. Zelnio and Frederick D. Garber}, collaboration = {}, title = {A beamforming algorithm for bistatic SAR image formation}, publisher = {SPIE}, year = {2010}, journal = {Algorithms for Synthetic Aperture Radar Imagery XVII}, volume = {7699}, number = {1}, eid = {769902}, numpages = {6}, pages = {769902}, location = {Orlando, Florida, USA}, url = {http://link.aip.org/link/?PSI/7699/769902/1}, doi = {10.1117/12.851871}, keywords = {SAR Processing, Bistatic SAR, Bistatic Spotlight-mode SAR, Autofocus, Autofocus in the TDBP Framework, Back-projection, Time-Domain Back-Projection, TDBP, Fast Back-projection, Fast-Factorized Back-Projection, FFBP, Spotlight SAR, Spotlight-mode data, Beamforming}, pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/jakowatzWahlYockyBeamformingBistatic2010.pdf}, owner = {ofrey}, }
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adhere to the terms and constraints invoked by each author's copyright.
This collection of SAR literature is far from being complete.
It is rather a collection of papers which I store in my literature data base. Hence, the list of publications under PUBLICATIONS OF AUTHOR'S NAME
should NOT be mistaken for a complete bibliography of that author.
Last modified: Wed Sep 8 19:32:46 2010
Author: Othmar Frey , Remote Sensing Laboratories (RSL), University of Zurich, Switzerland .
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