A two-dimensional production system for grouping persistent scatterers in urban high-resolution SAR scenes

Modern spaceborne SAR sensors like TerraSAR-X offer ground resolutions of about one meter in range and azimuth direction which allows for the discrimination between different facade elements. Those objects often feature a trihedral structure, which leads to a strong radar response due to triple-bounce reflection. The resulting radar signal is frequently observed to be temporally stable and usually shows a large amplitude (Persistent Scatterer, PS). Our aim is to aggregate single PS to lattices using Gestalt theory. This is a very important step in the process of unveiling the physical nature of PS since it simplifies the fusion with supplementary data like oblique view aerial images. We use a two stage 2D production system which exploits the knowledge abut mapping of 3D objects into the SAR imaging geometry. In the first step, the production system groups those PS, which are vertically aligned in the real world, to rows. In a second step, those groups are merged to regular lattices with the second orientation corresponding to the horizontal alignment of facade elements. The results show the benefit of aggregating points to lattices by the possible distinction of facade orientations.