Radar differential interferometry based on permanent scatterers and its application to detecting regional ground subsidence

Synthetic aperture radar differential interferometry (DInSAR) based on permanent scatterers (PS) may overcome or mitigate two main disadvantages, i.e., radar signal decorrelation and atmospheric delay influence, which often take place in the conventional DInSAR. This paper analyzes all the processing procedures involved in PS-based DInSAR. Considering that deformation is of temporal correlation and topographic phase is proportional to normal baseline, the method of generating PS network is proposed. A parametric adjustment method is adopted to estimate total optimum solutions of subsidence rates and elevation corrections in the PS network. With the proposed algorithm, the experiment is performed to extract subsidence information over Shanghai using ERS-1/2 C-band SAR images taken during the latest 10 years. Deformation, elevation correction and atmospheric phase on PS points are effectively separated and the subsidence rate field with high resolution is presented. The results obtained from PS network are in a good agreement with leveling measurements.