Parameter estimation for the phase statistics in interferometric SAR

In interferometric SAR applications, the complex coherence between two channels, ρe^jθ, and the effective number of looks, n, are required to describe the joint channel statistics. Accurate modeling of the statistics is critical in the determination of Ground Moving Target Indication (GMTI) CFAR detection rules in along-track interferometry, and the estimation of topography accuracy in across-track interferometry. In this paper, we propose a method for estimating n and ρ based on the interferometric phase density function. We validate the robust, real-time implementable method with real SAR data in various types of terrain. Particularly, we show how the method can be extended to model the phase distribution even in extremely heterogeneous terrain. We show that the estimation relies only upon the multi-looked interferogram, without reference to the individual channels thereby reducing data storage requirements.