Second-Order Ocean Surface Cross Section for Shipborne HFSWR

To investigate the characteristics of sea clutter in monostatic shipborne high-frequency surface-wave radar (HFSWR) with uniform linear motion, the second-order patch scatter cross section is derived. With the previously proposed first-order ocean surface cross section, both cross sections could be reduced to the existing results in land-based HFSWR. Illustrations and discussions are provided on the basis of the simulation results for different situations. Although the spread Bragg lines vary with the ocean surface wind direction, the second-order contributions contaminate the energies of the Bragg lines in the high sea state, which may affect the application of shipborne HFSWR to wind direction extraction from the ratio of the positive and negative Bragg line energies. The derivations and analyses would be of importance to future investigations and applications, not only for target detection but also for ocean remote sensing.