Ortho-rectification of high-resolution SAR image in mountain area by DEM

Because of the side-looking imaging characteristics, the quality of Synthetic Aperture Radar (SAR) image is badly affected by variable terrain. Such terrain can introduce large displacements in the SAR image geometry that inhibits the collocation of SAR-derived quantities with geographically referenced information acquired from other sources. So it is necessary to eliminate such inherent geometric distortions by generating a radar ortho-imagery that corresponds to a well defined map projection. In this paper, aiming at the newest high-resolution SAR data-RADARSAT-2 and TerraSAR-X, an effective ortho-rectification method was studied in detail and the result showed this method could achieve high geo-location accuracy.