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

Abstract

An algorithm is proposed 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: (1) patching the void cells in the SRTM DEM; (2) determining a one-to-one correspondence between the interferogram and the SRTM DEM; (3) eliminating the phase trend between the original and the simulated interferogram. This algorithm can be used to facilitate phase unwrapping problem. Conventional techniques treat phase unwrapping as an optimization problem, in which the total branch cuts or the gradient errors are to be minimized. The phase unwrapping is considered as a blind procedure in these techniques and carried out without any external assistance. The purpose of this paper is to provide a knowledge-based technique by introducing the SRTM DEM as an assistance to the phase unwrapping. Some experimental results with JERS data verify the theoretical analysis and show that the method can improve the performance of phase unwrapping to a great extent.

Acknowledgment

The authors thank Dr. Zheng Xiang for helpful technical discussions.