Modeling OTH Radar Sea Clutter in Range-Dependent Atmospheric Ducts

Abstract

The accurate modeling of sea clutter for over-the-horizon (OTH) radar constitutes a classical multiscale physical problem, necessitating the precise coupling of kilometer-scale propagation links with meter-scale sea surface roughness characteristics. In order to remediate the physical inconsistencies engendered by the decoupled calculation of radio wave propagation and sea surface scattering in prevailing methodologies, this article puts forth a proposed integrated propagation-scattering physical simulation framework. The framework’s foundation is predicated on the implementation of a bidirectional propagation-scattering coupling mechanism, which integrates the propagation loss correction induced by sea surface roughness with a high-fidelity scattering kernel incorporating two-stage foam evolution and multipath effects into a unified framework. At the implementation level, a heterogeneous parallel architecture based on C++/CUDA is constructed, which effectively resolves the challenge of electromagnetic scattering calculation for massive time-varying sea surface facets. Using measured data from the South China Sea, the model’s validity in describing the statistical distribution and spectral characteristics of sea clutter is substantiated. Moreover, a series of numerical experiments is conducted based on this model to investigate the impact of range-dependent atmospheric ducts on the characteristics of long-range sea clutter. The simulation framework under consideration provides critical data support and a theoretical basis for the performance analysis of OTH radar systems and the development of high-precision atmospheric duct inversion algorithms.