On the extension of the SBAS algorithm for the generation of ERS/ENVISAT deformation time-series

Abstract

We present a differential synthetic aperture radar interferometry (DIFSAR) technique for generating displacement maps and deformation time-series by exploiting data acquired by the ERS and ENVISAT/ASAR systems. The proposed solution is focused on investigating large scale displacements with a relatively low spatial resolution (of about 100 /spl times/ 100 m). Since the two radar sensors operate at different carrier radar frequencies, the easy computation of cross-platform interferograms is prevented, thus leading to independent subsets of interferograms. An easy and efficient way to combine ERS/ERS and ENVISAT/ENVISAT multilook interferograms is represented by the application of the Small BAseline Subset (SBAS) strategy. This solution guarantees the continuity in the monitoring of the Earth's surface by benefiting of the present and future availability of ASAR data, preserving the archived ERS data. The presented results, obtained on a descending ERS and ENVISAT SAR data set, spanning the time interval from 1992 until October 2003, are relevant to the Napoli Bay area (Italy) and clearly demonstrate the effectiveness of the proposed extension of the SBAS technique.