FM interference suppression for PRC-CW radar based on adaptive STFT and time-varying filtering

The influence of frequency modulation (FM) interference on correlation detection performance of the pseudo random code continuous wave (PRC-CW) radar is analyzed. It is found that the correlation output deteriorates greatly when the FM interference power exceeds the anti-jamming limit of the radar. According to the fact that the PRC-CW radar echo is a wideband pseudo random signal occupying the whole TF plane, while the FM interference only concentrates in a small portion, a new method is proposed based on adaptive short-time Fourier transform (STFT) and time-varying filtering for FM interference suppression. This method filters the received signal by using a binary mask to excise only the portion of the TF plane corrupted by the interference. Two types of interference, linear FM (LFM) and sinusoidal FM (SFM), under different signal-to-jamming ratio (SJR) are studied. It is shown that the proposed method can effectively suppress the FM interference and improve the performance of target detection.