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Prediction, detection and correction of Faraday: rotation in full-polarimetric L-Band SAR data / F.J. Meyer in IEEE Transactions on geoscience and remote sensing, vol 46 n° 10 Tome 2 (October 2008)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 46 n° 10 Tome 2 (October 2008) . - pp 3076 - 3086 Titre : Prediction, detection and correction of Faraday: rotation in full-polarimetric L-Band SAR data Type de document : Article/Communication Auteurs : F.J. Meyer, Auteur ; J.B. Nicoll, Auteur Année de publication : 2008 Conférence : IGARSS 2007, International Geoscience And Remote Sensing Symposium, sensing and understanding our planet 23/07/2007 27/07/2007 Barcelone Espagne Proceedings IEEE Article en page(s) : pp 3076 - 3086 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] bande L [Termes IGN] correction ionosphérique [Termes IGN] données polarimétriques [Termes IGN] image ALOS-PALSAR [Termes IGN] propagation ionosphérique Résumé : (Auteur) With the synthetic aperture radar (SAR) sensor PALSAR onboard the Advanced Land Observing Satellite, a new full-polarimetric spaceborne L-band SAR instrument has been launched into orbit. At L-band, Faraday rotation (FR) can reach significant values, degrading the quality of the received SAR data. One-way rotations exceeding 25° are likely to happen during the lifetime of PALSAR, which will significantly reduce the accuracy of geophysical parameter recovery if uncorrected. Therefore, the estimation and correction of FR effects is a prerequisite for data quality and continuity. In this paper, methods for estimating FR are presented and analyzed. The first unambiguous detection of FR in SAR data is presented. A set of real data examples indicates the quality and sensitivity of FR estimation from PALSAR data, allowing the measurement of FR with high precision in areas where such measurements were previously inaccessible. In examples, we present the detection of kilometer-scale ionospheric disturbances, a spatial scale that is not detectable by ground-based GPS measurements. An FR prediction method is presented and validated. Approaches to correct for the estimated FR effects are applied, and their effectiveness is tested on real data. Copyright IEEE Numéro de notice : A2008-527 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2008.2003002 En ligne : https://doi.org/10.1109/TGRS.2008.2003002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29597 [article]

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Simultane Schätzung von Topographie und Dynamik polarer Gletscher aus multi-temporalen SAR Interferogrammen / F.J. Meyer (2004)

Public Titre : Simultane Schätzung von Topographie und Dynamik polarer Gletscher aus multi-temporalen SAR Interferogrammen Titre original : [Simultaneous estimation of topography and motion of polar glaciers and ice sheets from multi-temporal SAR interferograms] Type de document : Thèse/HDR Auteurs : F.J. Meyer, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2004 Collection : DGK - C Sous-collection : Dissertationen num. 579 Importance : 113 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5018-1 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] Arctique [Termes IGN] calotte glaciaire [Termes IGN] glacier [Termes IGN] image multitemporelle [Termes IGN] image radar moirée [Termes IGN] interferométrie différentielle [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] position directe Résumé : (Auteur) This thesis presents a new technique to simultaneously estimate topography and motion of polar glaciers and ice sheets from multi-temporal SAR interferograms. In this approach the unknown parameters, i.e. topography and surface displacement, are estimated from a redundant number of observations. The resulting redundancy is systematically used to attach realistic accuracy and robustness measures to all estimated unknowns and to reveal possible gross errors in the observations or errors in the model. Additionally, the redundancy facilitates replacing very restrictive model components by more flexible models with a higher amount of free parameters. This leads to a better description of the real behavior of the object. The approach combines several SAR interferograms into a least-squares adjustment based on the Gauss-Markov model. In order to connect the multi-temporal data sets, a spatio-temporal model is proposed that describes the properties of the surface and its temporal evolution. The parameterization of the model can be adapted considering the properties of the object under investigation. Tests with simulated data show that, with this technique, both topography and motion of polar ice caps can be estimated with an accuracy of a few meters or a few centimeters per day, depending on the configuration of the adjustment. The quality of the estimated parameters depends on the accuracy of the phase observations, the observation geometry, and the number of involved data sets. Analyses of the robustness of the approach additionally indicate a high robustness of the estimated unknowns with respect to gross errors in the observations. The influence of the atmospheric path delay on the unknowns is analyzed and quantified for various observation geometries and different atmospheric conditions. It is shown that errors in the assumed deformation model significantly falsify the estimated parameters. Thus, the configuration of the spatio-temporal model must be chosen carefully. In addition to the estimation of surface topography and motion, the method and its inherent analysis tools allow to determine the observation geometry that is necessary to reach a pre-defined accuracy level in advance. Therefore, the method is a very useful tool for project planing. By means of a case study aimed at the observation of a huge ice dome in the Russian arctic the feasibility of the approach in real-life situations is demonstrated. Numéro de notice : 13257 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54941

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