Motion Compensation Method Using Direct Wave Signal for CTSR Bistatic HFSWR

Coast-transmit ship-receive (CTSR) bistatic high-frequency surface wave radar (HFSWR) can fully exploit the flexibility of moving platforms and the anti-interference advantages of bistatic radar. However, the platform motion can cause the spread of target echo in the frequency spectrum and reduction of amplitude, which is not conducive to detection. In this letter, a motion compensation method using a direct wave signal is proposed for CTSR bistatic HFSWR. First, the frequency shift characteristics of direct wave signal and target echo are analyzed by simulation. The simulation results show that the platform motion has a similar modulation form on both target echo and direct wave signal, and their difference is mainly caused by different azimuths. In addition, the direct wave signal is only affected by the platform motion, so it can be used to obtain the platform motion effect. Then, the proposed method uses a direct wave signal as the reference information to estimate and eliminate the phase modulation caused by the platform motion. At last, the effectiveness of the method is verified by the experiment based on simulated and measured attitude data.