DEM CORRECTION AND MEAN SURFACE DISPLACEMENT RATE RETRIEVAL FROM A STACK OF WRAPPED MULTI-TEMPORAL DINSAR INTERFEROGRAMS

In this work, a new technique for the correction of a digital elevation model (DEM) and the retrieval of the ground mean displacement rate of an investigated area, by the analysis of a sequence of (wrapped) differential SAR interferograms is presented. The method is based on the solution of a non-linear optimization problem that does not require the preliminary execution of any phase unwrapping operation. As a consequence, the achievable estimates are not disturbed by phase unwrapping (PhU) errors. The estimation of the displacement rate may reveal (in most cases) particularly suitable for retrieving geophysical information on the sources responsible for the observed deformations. Moreover, the estimates of the DEM inaccuracies and the ground displacement rate can be used within advanced multi-temporal DInSAR processing chains for the retrieval of surface deformation time-series, with the aim to facilitate phase unwrapping operations and discriminate the desired signals (due to deformation) from residual phase artifacts. The first experimental results, carried out by applying the proposed method to stacks of simulated and real interferograms, demonstrate the validity of the proposed approach, and get a first coarse evaluation of the estimates accuracy.