The Second-order Monostatic HF Radar Cross Section for Target-Ocean Patch Scatter

An analysis addressing the second-order scattering of electromagnetic radiation from hard targets embedded in time-varying random rough surfaces is presented. The analysis uses a second-order electric field derived in previous work involving scattering from rough surfaces as a starting point before introducing a discrete surface target. The case of patch scatter is presented, where two scatters occur in the same vicinity (i.e. within the same scattering 'patch' as defined by the radar operating parameters), with the first scatter located on the target, and the second scatter occurring on the rough surface. A second-order radar cross section corresponding to this phenomenon is developed. The cross section expression is computed for two example protrusions and compared with existing models of ocean scatter. The results suggest that under certain conditions some targets may produce a detectable scatter.