A fast physical optics (FPO) algorithm for double-bounce scattering

The fast physical optics (FPO) method for computing back-scattered fields over ranges of aspect angles and frequencies is extended to encompass double-bounce scattering. Computations are performed within the framework of the physical optics approximation appropriate in the high-frequency regime. The proposed algorithm is directly applicable to fixed angle bistatic configurations and a variety of double scattering settings. The method comprises two steps: 1) decomposition of the scatterer into subscatterers and computation of the scattering amplitudes of all pairs of subscatterers and 2) interpolation, phase correction, and aggregation of the scattering amplitude patterns of all subscatterer pairs into the pattern of the entire scatterer. The proposed method is especially suited for generating synthetic data for radar imaging simulations.