The PSIG approach to persistent scatterer interferometry

This paper describes some of the key features of the Persistent Scatterer Interferometry chain of the Geomatics (PSIG) Division of CTTC. The paper firstly provides an overview of the entire PSI chain. It then focuses on the first part of the chain, which provides the input data for the estimation of the Atmospheric Phase Screen (APS). In this part, the so-called Cousin Persistent Scatterers (CPSs) are sought, which are Persistent Scatterers (PSs) characterized by a moderate spatial phase variation that ensures a correct phase unwrapping. The main output of this part of the chain is a set of correctly unwrapped and temporally ordered phases, which are computed on CPSs that cover homogeneously the area of interest. In order to do so a procedure to check the consistency of phase unwrapping is used. The paper describes the used algorithms and illustrates their performances using a set of TerraSAR-X StripMap images over the metropolitan area of Barcelona.