First-order Sea Clutter Spectrum Extraction Based on SNR Method for HF Hybrid Sky-surface Wave Radar

The characteristics of frequency shift and broadening of first-order sea clutter for High Frequency Hybrid Sky-Surface Wave Radar (HFHSSWR) make it harder to isolate the first-order sea clutter spectrum than that of High Frequency Surface Wave Radar (HFSWR). In this paper, the characteristics of first-order sea clutter for HFHSSWR are investigated, and based on its continuously distribution character on the range-Doppler spectrum, the Signal-to-Noise Ratio (SNR) method is used to isolate the first-order sea clutter spectrum for HFHSSWR. From the quantitative analysis of the frequency shift and broadening of the first-order clutter spectrum caused by the bistatic angle, the ionospheres' conditions and the ocean current, the estimation method and the value ranges of three parameters are given, which are the center location, the width of first-order sea clutter spectrum and the spacing of the two first-order sea clutter peak. 2-D SNR method is used to solve the problem that the first-order spectrum boundary can