Spatial decorrelation evaluation for interferometric SAR

SAR interferometry based on image pairs acquired by different antennas enables the topographic mapping and ground moving target indication. Both the generated DEM accuracy and the clutter suppression performance are determined by the coherence of SAR image pairs. The baseline perpendicular to the SAR trajectory is one of the most important factors that affect the coherence, which varies with the property of the terrain. In this paper, the geometry between the perpendicular baseline and the terrain is researched, and the effect of terrain on coherence is presented. Then a more accurate formula for calculating the correlation coefficient is deduced in combination with the frequency characteristic of radar signals. The calculation results conform to the simulation results.