Experimental and theoretical validation of a GTD-based SAR simulator

In previous paper, a ray-racing model for urban SAR imaging and simulation was described in which a physical optics extension of the geometrical theory of diffraction (GTD) was used to include diffraction returns in calculating the specular backscatter from the scene. This theory is based on that the most important contributions towards the scattered field come from an area in the neighborhood of some critical points on the scattering surface. For a planar surface, three critical points may be regarded; specular, edge- diffraction and corner-diffraction points. A physical optics version of PoGTD was taken with the approximate diffraction coefficients derived using physical optics approximations to canonical problems. The results from the simulator are examined and validated by comparing them with theoretical and experimental results calculated and found in an annerchaic chamber using simple targets. The objects were chosen to cover different combination of the critical points, i.e. specular, edge- and vertex-diffraction which contribute towards the backscattered field. For both set of data the co-polarized data are presented and compared.