In the surface deformation monitoring, synthetic aperture radar differential interferometry (D-InSAR) has the advantages
of all-weather, large-scale and high accuracy, it is hard to form interferogram for limited factors such as spatial
decorrelation, temporal decorrelation and atmospheric effect. For the reason, the method of PS-DInSAR was proposed.
However, the method needs so many SAR images, more than twenty scenes. Therefore, the method based on the phase
stacking of PS for surface deformation monitoring was proposed and verified. The PS-DInSAR model and D-InSAR
model are combined and simplified under certain conditions that assume the phase error of atmospheric disturbances are
random and equal in an interferogram and the deformation is linear. The optimal master image for interferometric
combinations is selected by comprehensive correlation function model. Then the PS points are detected and the Delaunay
triangle is established according to the PS. The Minimum Cost Flow is used based on the Delaunay triangle of PS to
unwrap the phase. Then the deformation and deformation rate are obtained by the linear analysis for temporal series of
interferograms. At last, nine ENVISAT images captured during 2003.6-2006.3 in Tianjin area were processed, and the
mean subsidence rate of this area was obtained.