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Repeat-pass SAR interferometry with partially coherent targets

Daniele Perissin(1), Alessandro Ferretti(2), Riccardo Piantanida(1), Davide Piccagli(1), Claudio Prati(1), Fabio Rocca(1), Alessio Rucci(1) and Francesco de Zan(1)

(1) Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
(2) Tele Rilevamento Europa T.R.E, Via V. Colonna 7, 20149 Milano, Italy


By means of the Permanent Scatterers (PS) technique, repeated spaceborne SAR images with slight low resolution (about 25m x 5m for ESA ERS and Envisat) can be used to estimate displacement (1mm precision) and 3D location (1m precision) of targets that show an unchanged electromagnetic signature. The main drawback of the PS technique is the limited spatial density of targets that behave coherently during the whole observation span (hundreds of PS per squared km in urban site, up to few points in vegetated areas). In this work we describe different solutions for multi-temporal analysis of SAR images that allow to extract information also from partially coherent targets. The core idea is to relax the restrictive conditions imposed by the PS technique: 1) we search for the most informative set of interferograms, discarding the usual PS single-master configuration; 2) for each target we search for the sub-set of reliable interferograms; 3) we take into account the possible extended nature of the targets by applying an adaptive spatial filtering. The results obtained in different test-sites allowed to increase significantly the spatial coverage of the estimate of height and deformation trend, especially in extra-urban areas.


Workshop presentation

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