On the extension of the SBAS technique for ERS/ENVISAT and full resolution interferogram processing

In this paper we present an extension of the Small Baseline Subset (SBAS) Differential Synthetic Aperture Radar Interferometry (DIFSAR) approach that allows us to combine data acquired from different, but geometrically compatible, sensors, such as the case of ERS and ENVISAT systems, and to detect and follow the temporal evolution of localized deformations by using full resolution interferograms. In the first case, the key idea is to consider images acquired by the ERS and ENVISAT radar systems to belong to independent subset; accordingly, no cross-interferograms are considered and the combination of the ERS/ERS and ENVISAT/ENVISAT interferograms is carried out by applying the basic strategy of the SBAS approach. For what concerns the full resolution data processing, it is based on the integrated use of two different set of DIFSAR interferograms generated at low (multi-look data) and high (single-look data) spatial resolution, respectively. The extended SBAS algorithm has been tested with data acquired by the ERS and ENVISAT satellites relative to the area of the city of Napoli (Italy) and the results have been validated by using geodetic data.