SAR super-resolution and characterization of urban targets: An advanced analysis on the physical nature of Synthetic Aperture Radar Permanent Scatterers through ERS and Envisat Interferometry

In this work about one hundred repeated spaceborne Synthetic Aperture Radar acquisitions at a relative low resolution (25m x 5m) have been exploited for identifying the 3D position of privileged targets with sub-meter accuracy. Moreover, by analyzing scattering pattern and polarimetric response of the targets, their main radar characteristics have been estimated and 5 urban target typologies have been distinguished: gratings, roofs, poles, dihedrals and trihedrals. The results of 3D positioning and characterization of thousands targets have been cross-checked with aerial photography and in-situ surveys. The identification of urban corner-reflectors has allowed the combination of data acquired with different carrier frequencies under different geometries. The temporal sampling rate of the displacement measure of corner reflectors has been doubled by combining adjacent parallel tracks. The spatial density of the targets has been increased up to three times by combining ascending and descending passes and high precision urban digital elevation models have been produced.