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High Resolution Differential Interferometry using time series of ERS and ENVISAT SAR data

Josep Closa(1) and Alain Arnaud(1)

(1) Altamira Information, C/ Roger de Llúria 50, ŕtic B, 08009 Barcelona, Spain


Abstract- During the last ten years, a long history of data has been acquired by the SAR sensors on board the ERS-1 and ERS-2 satellites offering a wide range of interferometric applications. With the launch of ENVISAT in 2002, the more advanced SAR (ASAR) has given continuity to the success of the remote sensing mission of the ERS satellites by ensuring and increasing the value of the archived ERS data. The subject of this study is to demonstrate the continuity of the interferometric measurements obtained from the combination of long temporal series of SAR differential interferograms in order to derive small subsidence displacements. The implemented technique makes use of either ERS SAR or ASAR differential phase measurements to generate long term terrain movement and precise DEM error maps with the same resolution as the original SAR images: estimations may be done in every pixel of the image without spatial interpolation. The algorithm is capable to use all the available phase information even in conditions of large baselines or platform instabilities giving place to large Doppler centroid variations. Such artifacts are handled by precise location estimate of the scatter within the pixel and accurate elevation extraction. One interesting by-product of this technique is the interpretation of the DEM errors as an approximation of a DSM (Digital Surface Model) in low density urban and peri-urban environments. Continuity on the displacements measured from both sensors after atmospheric artifacts removal will be shown in the results


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Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry