Combination of low and high resolution images SAR for differential interferometry

In this paper we propose a combination of low resolution (LR) and full resolution (FR) SAR images for differential SAR interferometry. The principal problem in such a combination is the volume scattering decorrelation that limits the useful baseline of the interferometric pair to very small, impractical values. A technique has been introduced to remove this decorrelation by exploiting a digital elevation model (DEM) of the area imaged. The resulting interferogram has the quality (in terms of coherence, or phase noise standard deviation) of a conventional FR interferogram, but reduced geometric resolution. The technique is suited to those differential interferometry applications where the resolution of the “differential” phase field to be monitored is much coarser than that of local topography. As a possible application, we propose a system that exploits the wide swath imaged by low-resolution ScanSAR modes for frequent monitoring hazardous areas.