FM interference suppression for PRC-CW radar based on STFT and median filtering

The influence of 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 limitation of the radar. According to the fact that the PRC-CW radar return signal is a wideband pseudo random signal occupying the whole TF plane, whereas the FM interference signal is well concentrated in the TF plane, a new method is proposed based on STFT and median filtering for FM interference suppression. This method implements the filtering of the received signal by substituting the median filter output for only a portion of the TF plane corrupted by the interference. The echo signals corrupted by two types of interferences including linear FM (LFM) and sinusoidal FM (SFM) forms under different signal-to-jamming ratio (SJR) situations are simulated. It is shown that the method can effectively suppress the FM interference and improve the performance of target detection significantly.