Modeling of Scattering Centers for Non-Ideal Surface Targets under Adverse Weather Conditions

Radar target characterization is typically performed under the assumption of ideal smooth metallic surfaces, without accounting for the combined effects of surface roughness and environmental dielectric loading. This paper presents a scattering center modeling framework for complex targets whose non-ideal surfaces are covered by a thin dielectric film - representative of water or snow accumulation under rain and snow conditions. A Gaussian roughness field is generated via the Fast Fourier Transform and applied to triangular mesh surfaces of complex targets through vertex normal mapping. A frequency-dependent coating correction factor, derived from the complex permittivity of water modeled after Liebe et al., is then incorporated into the physical-optics-based scattering computation to account for the thin dielectric layer. Numerical results on a scaled tank model demonstrate that the presence of a surface water film produces measurable perturbations in full-angle radar cross section (RCS), and that inverse synthetic aperture radar (ISAR) images exhibit distinct scattering center redistribution compared to both the ideal metallic case and the bare rough-surface case. The proposed method provides a practical tool for high-fidelity radar signature simulation of ground and maritime targets under adverse weather.