Exploitation of SRTM DEM in InSAR processing and its application to phase unwrapping problem

A novel approach is proposed in this paper to exploit the shuttle radar topography mission (SRTM) digital elevation model (DEM) in the interferometric synthetic aperture radar interferometry (InSAR) processing. The proposed algorithm includes three steps: the first step is to patch the void cells in the SRTM DEM; the second step is to determine a one-to-one correspondence between the interferogram and the SRTM DEM; the third step is to eliminate the phase trend between the original and simulated interferogram. Meanwhile this algorithm can be applied to help the phase unwrapping problem. Conventional techniques approach phase unwrapping as an optimization problem, where the total branch-cuts, or the gradient errors, etc. are to be minimized. Generally speaking, they consider phase unwrapping as a blind procedure, i.e., without any external guidance. The purpose of this paper is to fill this gap by introducing the SRTM DEM as a phase unwrapping guidance. Some experimental results with JESR verify our theoretical analysis and show that our method can improve the performance of the phase unwrapping to a great degree.