Changes of dominant scatterers and propagation paths as a possible origin of singular points in radar interferometry: Experimental analysis

In Synthetic Aperture Radar (SAR) interferometry(InSAR), we generally expect that there is only one unique dominant scatterer in a pixel. To make a SAR interferogram, we have to observe every place twice. Between the observations, the dominant scatterer is expected to unchange. However, in actual situations, there are multiple scatterers in one pixel, and a dominant one may change observation by observation. Our main idea in this paper is that this change happens more frequently than we have expected, and that this phenomenon can generate singular points (SPs) in the SAR interferogram which prevent us from accurate phase unwrapping. Here, we present the results of the preliminary experiments using real aperture radar system, which suggest one of the mechanisms of the singular point generation.