Interferometric SAR Space-Varying Filtering of X-Band SRTM Data

Interferometric SAR data should be filtered in order to remove the geometrical decorrelation caused by the presence in the signal pair of “incoherent” components not illuminated in both the passes. This operation is generally carried out, via common band filters, by assuming a planar topography whereas in the real, non-planar topography case, the problem becomes space variant. We discuss the application of recently derived optimal, Minimum Mean Square Error, space-varying filters for the coherence optimization to the SAR data of the X-Band SRTM mission. We also discuss the extension of the analysis in the azimuth direction to the problem of optimally filter the Doppler Centroid decorrelation.