Coherent Point Targe Analysis for Estimating Subsidence Velocity in Hong Kong with a Time Series of Envisat Asar Data

This paper presents a new time-series InSAR analysis approach, Coherent Point Target Analysis (CPTA), to accurately map surface subsidence. The approach focus on the selection and analysis of sparse coherent point targets which exhibit phase stability over a long period of time. By jointly exploiting temporal and spatial characteristics of the interferometric phases collected from coherent targets, the CPTA approach allows obtaining reliable estimated results of temporal deformation evolution and average deformation velocity, even when few SAR images are available. With the CPTA analysis, experiments are carried out on a time series of ENVISAT ASAR data acquired over Hong Kong, China, characterized of ground settlement induced by reclamation activities. The estimated subsidence velocity is compared with ground surveying data and the validation result show a high consistency between the two data sets.