Exploitation of SRTM DEM in InSAR 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 (InSAR) data 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. This algorithm can be applied to facilitate 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 guidance for phase unwrapping. Some experimental results with JESR verify the theoretical analysis and show that the method can improve the performance of the phase unwrapping to a great extent.