Monitoring urban subsidence with coherent point target SAR interferometry

Spaceborne SAR interferometry (InSAR) is a well known microwave remote sensing technique which has been applied for topography mapping and ground motion monitoring by exploiting phase difference from SAR data acquisition with relevant large spatial scale and high precision. The developed Permanent Scatterers Interferometry (PSI) is a further step of InSAR technique which offers a convenient processing framework that enables the use of all data acquisitions. It aims to bypass the problem of geometric and temporal decorrelation by considering long term coherent point. Furthermore, by using a large number of data, atmospheric signal is estimated and compensated for. We present in this work the development of an improved PSI, called Coherent Point Target InSAR, for land subsidence velocity field estimation in urban area as well as rural area in China. A series of case studies demonstrate the ability of CPT InSAR for monitoring ground subsidence felid with relevant large spatial extent as well as small area.