DETECTION OF GAPS BETWEEN LAND AND BUILDING SURFACE DISPLACEMENT BY PSINSAR AND SBAS ANALYSIS USING L-BAND PALSAR DATA

This paper presents the potential of differential synthetic aperture radar (SAR) interferometry to detect the gaps of the displacement rate between the buildings and the land surface. We assumed that the information about building surface displacement can be extracted from single look SAR images whereas the information about land surface deformation can be extracted from multi look SAR images. The proposed method implements Persistent Scatters (PS) InSAR and Small Baseline SAR (SBAS) techniques for respective purposes. Subtraction of the two results can detect the gaps. In addition, the proposed method corrects orbital phase error to mitigate phase ramp of the interferograms without phase unwrapping that is widely known to cause errors in applying to the areas where terrain is fluctuating. We applied the proposed method to Bangkok, Thailand, and found that it succeeded in detecting areas those have severe displacement rate gaps.