Target Above Random Rough Surface Scattering Using a Parallelized IPO Accelerated by MLFMM

The radar cross section (RCS) of targets above random rough surfaces having impedance boundaries is evaluated using a developed parallelized iterative physical optics. Integral calculations are accelerated using the multilevel fast multipole method (MLFMM). For example, the RCS of a boat above a Gaussian random rough surface occupying a (100/3λ)3 volume, with λ being the wavelength at the operation frequency of 1 GHz for one incidence angle, is computed within about 42 s. The result is verified with method of moment-MLFMM which takes about 9.4 min. The backscatter RCS of a (9λ)³ dihedral above a random rough surface for different root-mean-square (rms) heights, correlation lengths, and incidence angles is examined. It is shown that a rough surface with an rms height of 0.2λ and a correlation length of λ can decrease/increase the RCS of a vertically placed impedance dihedral corner reflector by about 5 dB at an elevation angle of 45°.