Deformation Rate Estimation On Changing Landscapes Using Temporarily Coherent Point INSAR

In areas undergoing large scale constructional developments, such as cities in most of developing countries, there are abundant scatterers that are only partially coherent in some observation period. In fact these scatterers still carry high-quality phase information at least in a subset of interferograms allowing us to estimate the deformation rates from them. Here the partially coherent scatterers as well as the persistently coherent scatterers are termed as Temporarily Coherent Points (TCPs). In this paper we provide two approaches for TCP identification. One is based on offset deviations during image pair coregistration procedure and the other one is based on Ambiguity Mad Median Ratio (AMMR). Since the TCPs might keep coherent in a subset of interferograms, we propose two deformation parameter estimators that can either be performed only with coherent phases of TCPs or have the ability to suppress the effect of decorrelated phases and phase ambiguities that are considered as “outliers” when taking all interferograms as observations. We apply the techniques to map land surface deformation over Macau, China. The results from our TCPInSAR processing have been confirmed by ground measurements.