HAF-based spectral analysis of first-order sea clutter in bistatic shipborne surface wave radar

Doppler frequency shifts of sea echoes in bistatic shipborne surface wave radar (BS-SWR) are simultaneously modulated by the velocity components projected from the motion of both platforms, and therefore the Doppler spectrum is much more complex than its counterparts in monostatic mode. In this paper, based on the dynamic geometric relationship among bistatic platforms and first-order sea clutter interferences, we claim that there exist dynamic Doppler-broadening components due to the unavoidably different motion of bistatic platforms. Then based on the built signal model of sea echoes only containing the first-order components, we analyze the time-varying characteristic via the high-order ambiguity function (HAF) method in both first- and second-order spectrum. By simulation results, finally, not only the above analysis is demonstrated, but also the difference are shown before and after attenuating the first-order sea clutter via an existing time-space cascaded filtering algorithm in both Doppler and acceleration domain, respectively.