Coherent vs. Persistent Scatterers: A Case Study.

Abstract

Precise interferometric SAR measurements as well as characterization and information extraction of individual targets can be performed on natural or artificial point-like scatterers in SAR images. This is due, mainly, to the possibility to estimate their phase information very accurately, widely unaffected by speckle. Up to now, by means of two different techniques, two categories of such point-like scatterers have been treated: the Persistent Scatterers (PSs) and the Coherent Scatterers (CSs). On one hand, PSs are characterized by long term temporal stability and are detected using long time series of acquisitions. They enabled the development of geophysical applications as millimetric terrain motion monitoring and accurate DEM refinement. On the other hand, CSs can be detected on a single SAR image basis, by exploiting image spectral correlation properties, without any assumption of temporal stability. They are very promising concerning parameters extraction as LOS rotation angle and dielectric constants estimation. Due to the wide spectrum of informations provided by the combination of the two concepts in this paper we investigate the CSs temporal stability and the relationships existing between CSs and PSs based on the analysis of image time series.