A Local Ray Incidence-Based Scattering Model for Targets on a Complex Rough Surface

This paper proposes a novel high-frequency scattering model for targets on complex rough surfaces. The core innovation is a local ray incidence-based technique that computes the reflection and multi-reflection components from targets and the coupling scattering components between targets and the background. This approach generates ray tubes exclusively from the target facet model. The background facet model is subsequently processed to perform ray-triangle intersection tests, while coupling scattering components are modified using the four-path principle. Background scattering is calculated via coherent-incoherent models, and diffraction components are computed using the Equivalent Electromagnetic Current (EEC) method. The accuracy of the proposed method is validated against full-wave numerical solvers, showing good agreement in radar cross-section (RCS) fluctuations. Compared to the traditional Shooting and Bouncing Rays (SBR) technique with EEC, the proposed method achieves a significant reduction in simulation time. This capability enables the rapid simulation of SAR images for targets on complex rough surfaces.