Cosmo-skymed very short repeat-pass SAR interferometry over rural areas: The VAL D'agri and potenza test cases in Basilicata, Italy

Abstract

Over the last three decades interferometric synthetic aperture radar (InSAR) techniques have attained a fundamental role in surface deformation monitoring. The main importance is given by two key factors: the exploitement of rich SAR data archives and the development of processing techniques able to extract information from these datasets. InSAR time series techniques such as permanent scatterers (PS) or SBAS have proven capable of estimating displacements to with 1 mm precision for targets that show a stable electromagnetic signature. At the same time the availability of SAR constellations with a reduced revisit time, such as the X band COSMO-SkyMed (CSK) and TerraSAR-X/PAZ satellites, has reduced the minimum detectable deformation gradient between two neighboring points and improved the theoretical precision given for a network of selected stable pixels. Independently from the applied processing methodology, the main drawback at X-band is the shorter time interval to temporal decorrelation. This effect can be partially mitigated by a short repeat time acquisitions plan. A technique able to deal with distributed scatterers is fundamental for extending the spatial coverage of the coherent area. In this paper we analyze the potential of X-band COSMO-SkyMed short repeat pass interferometry over a rural area in the southern part of Italy for assessing the capabilities and limitations of the Quasi-PS (QPS) technique in an X-band non-optimal scenario.