Abstract:An analysis was made of the major factors causing loss of correlation in permanent scatterer synthetic aperture radar differential interferometry.A method considering atmospheric delay variety differences was adopted to optimally select the common master image for PSDInSAR.Its specific function model,modeling principle and solution were provided.The original data came from continuous GPS permanent station and ENVISAT satellite ASAR images in Tianjin area from European Space Agency.Based on Bernese 5.0,Matlab7.1 and Shell programs,a test is made on the optimum selection of common master image fusing GPS data.The experiment shows the model correlation coefficient method fusing GPS data can select the optimal common master image from many SAR images rapidly and correctly,which guarantees the high-precision of PSDInSAR deformation survey.