SBAS-DInSAR analysis by using post-2001 ERS-2 aquisitions

EUILLADES, LEONARDO; EUILLADES, PABLO A.; BLANCO, MAURO

Roma

Workshop; Fringe 2009 Workshop; 2009

European Space Agency

The motivation of this work is the lack of SAR data for long-term DInSAR deformation analysis over our area of interest. We investigate the capabilities of SBAS-DInSAR [1] algorithm to analyze deformation by using ERS-2 scenes acquired after the 2001 gyro failure, and affected by erratic doppler centroids. The available SAR data in some regions, particularly in Argentina, is limited to those produced by the European Remote Sensing satellite (ERS-2) after late 2000. Traditional DInSAR processing “a priori” discards those scenes whose doppler centroid is far from nominal. It means, in a practical sense, to discard most of the scenes, seriously compromising the usefulness of the remaining ones. The proposed methodology makes profit of the SBAS concept, extending it to small doppler subsets. We consider the whole ERS-2 dataset without “a priori” discarding scenes with doppler centroid not occurring inside the traditional +-PRF/2 bounds. Scenes with Doppler centroid far from nominal [2] are included in two different ways: 1) some of them constitute separated doppler subsets, 2) others get linked through chains of small doppler differences to the main subset. Restrictions on spatial and temporal baseline are like in traditional SBAS processing. We processed a set of 39 ERS1-2 scenes over a well known deformation affected region in Argentina (Mendoza metropolitan area). The temporal span ranges between 1997 and 2006. By using the small Doppler concept 30 of them result useful. The discarded scenes are mainly those acquired in 2000 and 2001. It is important to note that, by using traditional processing approach, only 12 to 13 scenes would have been included. For the sake of comparison, we used deformation time series obtained by SBAS processing of 29 ENVISAT ASAR scenes [3] and GPS independent measurements. Ingeneral, our results are in good agreement with both GPS and ENVISAT-SBAS data.[1] P. Berardino, G. Fornaro, R. Lanari, and E. Sansosti, "A New Algorithm for Surface Deformation Monitoring Based on Small Baseline Differential SAR Interferograms," IEEE Transactions on Geoscience and Remote Sensing, vol. 40, pp. 2375-2383, November 2002. [2] B. Rosich, D. Esteban, G. Emiliani, P. Meadows, B. Schattler, and R. Viggiano, "ERS-2 Mono-Gyro piloting: Impact on ERS-2 SAR data quality and applications performance," ESA-ESRIN, Roma ES-TN-ADQ-BR02, 22 june 2000. [3] L. D. Euillades, M. H. Blanco, A. Pepe, and P. A. Euillades, "SBAS-DInSAR surface deformation analysis of the Mendoza region (Argentina) by using ENVISAT ASAR data.," in Fringe 2007, ESRIN, Frascati, Italy, 2007.