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PSIC-4: Validation and Intercomparison of Persistent Scatterers Interferometry. Main results.

Daniel Raucoules(1), Luc Closset(1), Christian Bremmer(2), Hans Veldkamp(2), Bernard Bourgine(1), Douglas Tragheim(3), Marcello De Michele(1), Luc Bateson(3), Michele Crosetto(4), Agudo Marta(4) and Marcus Engdahl(5)

(1) BRGM, 3 avenue C. Guillemin, 45060 Orleans cedex 2, France
(2) TNO, Princetonlaan 6, 3508 TA Utrecht, Netherlands
(3) BGS, Kingsley Dunham, Centre Nottingham, NG12 5GG, United Kingdom
(4) IG, Parc Mediterrani de la Tecnologia, Avinguda del Ca, E-08860 Castelldefels, Spain
(5) ESA/ESRIN, Via Galileo Galilei, Casella Postale 64, E-08860 Castelldefels, Italy


This presentation will describe the main results of the Persistent Scatterers Interferometry Codes Cross Comparison and Certification for long term differential interferometry(PSIC4) project, funded by ESA after the recommendations of FRINGE 2003. The project (2005-2007) aimed to compare the PSI (Persistent Scatterers Interferometry ) deformation results obtained by 8 participant teams having produced a PSI algorithm on the same given test site using the same SAR images set (107 ERS and 10 ASAR images) with ground based deformation data (levelling) and respect to each other. The objectives of these two series of tests (named validation and intercomparison) were to assess the absolute accuracy of each proposed algorithms and to examine possible discrepancies between the results. The study was decided to be a blind test: no a priori information on the characteristics of the deformation was provided to the teams and the deformation results were provided to the validation group in an anonymous format. The selected test site is located near Gardanne (South of France). In the last decades, subsidence related with long wall mining (coal extraction) affected the area and is still monitored by the coal authority. Discrepancies (for validation and intercomparison) higher than initially expected were observed. The specificity of the test site (non-linearity and deformations up to several cm/yr) seems to be the main reason of these reduced performances as no prior information was used to "tune" the processing parameters. This point does not invalidate the method, which is a unique tool considering its different abilities in terms of mapping and monitoring of ground deformation. Though, in a general operational case it illustrates the importance of having a strong interaction with the end-user of the data in order to adapt the procedure to the characteristics of the deformation and to the needs of the user.


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