An Effective Composite Scattering Model for the Sea Surface with a Target based on the TSBR-TSM Algorithm

The hybrid method of Shooting and Bouncing Ray (SBR) and Two Scale Model (TSM) based on the facets model (i.e., SBR-TSM) is proposed in the published literature to efficiently calculate the composite electromagnetic (EM) scattering from the electrically large sea surface with a target. However, the mesh size of sea surface is about 20 times the Bragg wavelength when the TSM method are employed to compute sea surface scattering, while the size of target facets is relatively smaller, especially for those with curved surfaces or fine structures. Thus, the excessive difference in facet size between the target and sea surface can easily lead to a decrease in the accuracy of determining the illuminated area during ray tracing (i.e., an increase in ray tracing error) in SBR-TSM method. To solve this problem, the hybrid method of the Two-scale Subdivision SBR (TSBR) and the TSM, named TSBR-TSM, is proposed in this paper. Comparative simulations are performed between the TSBR-TSM, the SBR-TSM algorithm, and the Multilevel Fast Multipole Method (MLFMM). The results show that TSBR-TSM method performed better in computational accuracy while ensuring computational efficiency, making it a promising advance in composite scattering modeling.