Monitoring Ground Subsidence Of Urban Region By Differential Sar Interferometry Based On Persistent Scatterers

Ground subsidence is a kind of severe geology disastar all over the world. Currently, there is approximately 930 thousands kilometers occur ground subsidence in China. How to prevent such phenomenon and solve the huge lose to our nation is significant and of great emergence. The great potential of Synthetic Aperture Radar Interferometry (InSAR) on topography and deformation mapping has long been recognized. However, repeat-pass InSAR sometimes cannot succeed due to the impacts of spatial decorrelation, temporal decorrelation and atmosphere heterogeneity, which greatly limit the practical applications of this technology. Persistent Scatterer Technique is one of the latest developments in radar interferometric processing. It is achieved by the analysis of the interferometric phases of individual point targets, which are discrete in spatial and present temporarily stable backscattering characteristics, with long time series of interferometric SAR images.Aimed to bypass the shortcomings of the traditional processing of D-InSAR, the PS technique obtained outstanding development these years. This paper analyzes the basic theory of the PS-InSAR, especially the key algorithms, and develops the Integer Least Squares methods used in phase model refinement. The main contributions of this paper are as following:1) Based on the PS point interferometric phase model, it developed the robust ILS PS-InSAR method, constructed the improved PS-InSAR method of ground subsidence extraction.2) Focus on the Suzhou city, it developed polynomial ground deformation model in the experiment and obtained positive results.3) This paper designed several experiments for simulated data and real data based on improved PS-InSAR method. The results represented that improved method contains the capability of modeling ground subsidence, estimating of parameters robustly, phase unwrapping correctly as well as processing automaticly. To sum up, it shows great potential to be a practical method in city ground subsidence monitoring.