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IEEE International Geoscience & Remote Sensing Symposium, IGARSS 2007, July 23-28, 2007, Barcelona, Spain, Proceedings; 01/2007
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EUSAR 2006;
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ABSTRACT: During the last decade, the techniques to generate digital elevation models (DEM) from SAR interferometry have been demonstrated and refined to a quasi-operational status using data from the ERS tandem mission. With this experience and an improved single-pass system concept, data from the Shuttle Radar Topography Mission (SRTM) acquired in 2000 have been used to produce a global DEM with unprecedented quality. However, under the extreme viewing conditions in mountainous terrain both ERS and SRTM suffer from or even fail due to the radar specific layover and shadow effect that leaves significant areas uncovered and poses severe problems to phase unwrapping. The paper quantifies the areas leading to layover and shadow, and shows innovative ways to overcome shadow and improve phase unwrapping in general.
FRINGE workshop, Frascati;
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ABSTRACT: TerraSAR-X is a national German satellite mission deploying a high resolution active phased array X-band SAR instrument into orbit in 2005. The configuration and parameterization of the instrument is highly flexible enabling StripMap, ScanSAR and SpotLight imaging modes in various polarizations in a wide range of different antenna beams. A special dual receive antenna mode will even provide the possibility for along track interferometry. The mission will be conducted by the German Aerospace Center DLR. The principle tasks of the ground segment are satellite commanding, SAR data reception and archiving, SAR data processing and distribution. The main item of the payload related part of the ground segment will be the new TerraSAR-X multi-mode SAR processor TMSP which adequately fits to the TerraSAR-X instruments flexibility. The TMSP design and selection of algorithms are mainly driven by the requirements, that all SAR raw data will be systematically analyzed, archived and focused in order to obtain medium resolution browse images for cataloguing. Further on, high precision phase preserving complex images as well as highly accurate multilook and geo-referenced images will be processed on user request. The effort of validation and the maintainability of the TMSP software are also taken into account for the system design. The finally developed algorithm for the TMSP is based on Chirp and Azimuth Scaling, SPECAN and Subaperture Processing. Therefore the already existing algorithms Chirp Scaling and Extended Chirp Scaling with Subaperture Processing which are optimal for the individual imaging modes have been analyzed and decomposed into their principal signal processing steps. Those which can be used commonly have been identified and rearranged, while mode specific steps lead to branches in the algorithm. Since the commonly required signal processing steps have to be implemented, tested, documented and validated only once, the resulting software gets more coherent and inexpensive than three individual mode specific SAR processors.
EUSAR 2004, Ulm, May 2004;
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ABSTRACT: This paper addresses the major requirements imposed on the TerraSAR-X SAR Payload Ground Segment and depicts its preliminary design. The on-request generated TerraSAR-X basic products are introduced. A SAR focusing algorithm candidate is selected.
Advanced SAR and CEOS WGCV SAR Workshop 2003, Saint-Hubert, Quebec, Canada, June 25 - 27, 2003;
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ABSTRACT: The TerraSAR-L system, currently being designed in a Phase B definition study, will provide ESA with its most powerful radar-imaging programme to date. The platform, based on a Snapdragon configuration, is optimized for and built around the 11 m x 2.9 m active phased array antenna of the L-band Synthetic Aperture Radar (L-SAR). The L-SAR features, on top of standard Stripmap and ScanSAR operations, full polarimetric capabilities, repeat-pass ScanSAR interferometry and a Wave Mode. The TerraSAR-L spacecraft flies in a near-polar sun-synchronous low Earth orbit. An attitude steering operation to reduce the Doppler frequency caused by the Earths rotation is foreseen. The knowledge of the relative distance between the spacecraft in orbit and a point scatterer on Earth during the radar illumination time, the so-called slant range history, is a crucial input for SAR focusing. Usually, this trajectory is approximated by an appropriate function. The validity of the approximation within the required accuracy margins has to be ensured. The applied attitude steering is a major driver for the Doppler parameters and thus the allowed approximations. This paper introduces the major TerraSAR-L orbit parameters and imaging configurations. Based on the nominal Kepler reference orbit, the round-orbit Doppler characteristics for TerraSAR-L are derived. The DLR developed Total Zero Doppler Steering is investigated as a suitable candidate for the TerraSAR-L attitude steering. A range trajectory approximation is investigated.
IGARSS, Anchorage Alaska, 20.-24. SEP 2004;
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ABSTRACT: The use of modern high resolution remote sensing satellites can revolutionise traffic research in a global scale. Within an area of more than 4.000 km in diameter around each ground receiving station traffic-data can be received from the satellite, processed and disseminated to the user in near-real-time. With on-board data storage acquisitions from other parts of the world can be downloades to a ground station with the German radar satellite TerraSAR-X which shall be launched already in summer 2005.
traffic technology International 2003.
