Analytical Evaluation of the Baseline Decorrelation in Bistatic Interferometric SAR Systems

We here analytically evaluate the spatial correlation coefficient of an interferometric pair obtained by combining two bistatic SAR acquisitions. The scattering surface is described as randomly rough, and the Kirchhoff Approximation (KA) or the first-order Small Slope Approximation (SSA1) are used to compute scattered fields. Both approximations lead to the same expression of the correlation coefficient, that generalizes to the bistatic case, with arbitrary acquisition geometry, the result available in literature for usual monostatic SAR interferometry.