No abstract

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 s 0 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 s 0 model and expand it to the bistatic clutter statistics.

Based on two low grazing angle simultaneously recorded out-of-plane bistatic and monostatic S-band sea clutter datasets, and covering bistatic angles from 30 • -120 • , we analyze the average normalized radar cross section (σ • ), and show that under the measurement conditions the ratio between σ • B and σ • M tends to a minimum around a bistatic angle of 90 • , particularly at horizontal polarization. However, the cross-polarized σ • was larger for the bistatic clutter at bistatic angles close to 90 • .

No abstract

Presented is a statistical analysis of vertically-polarised bistatic sea clutter data, with bistatic angles ranging from 308 to 908, compared with simultaneously-gathered monostatic clutter data. It is found that there is no significant change in the bistatic reflectivity compared to the monostatic except close to bistatic angles of 908. It is found that the shape parameter of the K-distribution fitted to the clutter is significantly higher for the bistatic clutter than for the equivalent monostatic clutter.