Persistent Scatterer InSAR

Chapter 3 introduces the mathematical framework of the Persistent Scatterer InSAR (PSI) estimation procedure. It starts with an overview of interferometric processing and the selection methods for Persistent Scatterer (PS) candidates, based on the amplitude observations. Subsequently, it is shown that the time and storage space consuming amplitude calibration can be replaced by performing pseudo-calibration: pseudo-calibration does not explicitly perform calibration, but adapts the PS selection parameter (normalized amplitude dispersion) to the equivalent for the uncalibrated stack of images. After selection of the PS candidates, earth surface deformation is estimated from double-difference phase observations. Both the functional and stochastic model are given. Furthermore, the Delft PSI (DePSI) estimation methodology, including Integer Least-Squares techniques, is explained.