Interferometric Assessment of SAOCOM-1 TOPSAR Data

Abstract

— SAOCOM-1 constellation operates in three acquisition modes: Stripmap (SM), TOPSAR Narrow (TNA and TNB) nd TOPSAR Wide (TW). Since repeat pass SAOCOM-1 TOPSAR acquisitions are not synchronized, the generation of the related interferometric products is not guaranteed, as it happens instead for the synchronized repeat pass TOPSAR acquisitions, such as those of Sentinel-1. In this work, we assess the suitability of SAOCOM-1 TOPSAR acquisitions for generating interferometric products. To this aim, we first discuss the constraints that must be fulfilled by the repeat pass non-synchronized TOPS acquisitions in order to make it feasible the generation of usable interferograms. Then, we verify if SAOCOM-1 TOPSAR acquisitions fulfill these constraints. For this purpose, we present an analysis based on the use of a data set composed by 18 TNB images relevant to a single subswath illuminating a region located in the South-West of Argentina.From this data set, we were able to select 48 pairs that guarantee the spectral superposition needed for interferometric purposes. We verified that the 50% of these 48 pairs fulfill the constraintrequired to avoid in the corresponding interferograms the presence of non-coherent azimuth stripes, whose azimuth extension depends on one side on the mis-synchronization percentage between the repeat pass acquisitions, and on the other side on the overlapping percentage between adjacent bursts of the same acquisition. Summing up, the presented analysis proves the potential of SAOCOM-1 TOPSAR acquisitions to obtain interferometric products, despite the absence of bursts synchronization between repeat pass acquisitions.