Interferometric Phase Statistics and Estimation Accuracy of Strong Scatterer for InSAR

Strong scatterer, such as sign point, exists in Interferometric synthetic aperture radar (InSAR) image. This paper focuses on the interferometric phase statistics of the strong scatterer in InSAR. Based on the InSAR echo model, the phase Probability density function (PDF) of strong scatterer is deduced. Then it is presented that interferometric phase PDF of strong scatterer is determined not only by correlation coefficient, but also by the characteristic parameter of strong scatterer, and the PDF becomes more centralized with the increasing of dominative scatterer intensity. According to interferometric phase PDF of strong scatterer deduced in this paper, the phase Cramer-Rao lower bound (CRLB) of strong scatterer is presented. The higher the intensity of dominative scatterer is, the better estimation accuracy can be obtained. It reveals that the accuracy of Interferometric phase estimation (IPE) assessed with strong scatterer is better than that in actual case. Therefore, Concomitant sign point (CSP) is presented to assess the accuracy of IPE. Simulation results illustrate the validity of the theory proposed in this paper.