Measurement and modelling of bistatic radar sea clutter

Bistatic radar is a subject of considerable present interest. Despite this, current understanding of the properties of bistatic clutter, and in particular, bistatic sea clutter, is limited at best. The purpose of this study is to present an analysis of the limited existing published radar data and to derive an empirical model, which expresses the variation of mean σ⁰ with the measurement geometry and sea conditions. This empirical model is then compared with electromagnetic (EM) scattering calculations using the composite model (sometimes called the two-scale model) to show the extent to which the EM model is able to reproduce the trends observed in the data. The results indicate where improvements to bistatic EM modelling are required (very low grazing angles and out-of-plane scattering), and a general need for more radar data to extend the empirical σ⁰ model and expand it to the bistatic clutter statistics.