Scattering from a target above a 1-D ocean-like surface from a fast rigorous method

The rigorous evaluation of the Normalized Radar Cross Section of an object above a one-dimensional rough sea surface (2D case) needs to numerically solve a set of discretized integral equations involving a large number of unknowns. So, in order to minimize the computation cost of the MoM (Method of Moments) procedure, the iterative domain decomposition method called EPILE (Extended Propagation-Inside-Layer Expansion) was used and then was combined with the FBSA (Forward-Backward with Spectral Acceleration) to calculate the local interactions on the rough sea surface. The resulting fast method is called EPILE+FBSA. In this paper, we take advantage of the rank-deficient nature of the coupling matrices, corresponding to the object-surface interactions, to further reduce the complexity of the method by using the ACA (Adaptive Cross Approximation). As a result, the coupling matrices are strongly compressed without a loss of accuracy and the memory requirement is then significantly reduced. For a cylinder above a rough sea surface, the results show the efficiency of the accelerated EPILE+FBSA+ACA method.