基于ASTFT和中值滤波的PRC-CW雷达FM干扰抑制方法

FM Interference Suppression for PRC-CW Radar Based on ASTFT and Median Filtering

通过分析调频(FM)干扰对伪码调相连续波雷达相关检测性能的影响,发现当FM干扰超出伪码调相雷达自身抗干扰容限时,相关输出严重恶化。针对该问题,考虑到伪码在时频平面上是近似均匀和平坦的,而FM干扰则具有较好的时频聚集性,该文提出了基于自适应短时傅里叶变换(ASTFT)和中值滤波的FM干扰抑制方法。该方法通过对时频平面上被干扰污染的部分进行中值滤波,实现了对FM干扰的抑制。对不同信干比情况下线性调频和正弦调频干扰抑制前后的相关输出进行了仿真分析。结果表明,该方法能够有效抑制干扰,使相关输出得到显著改善。

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 limitation of the radar.According to the fact that the PRC-CW radar return signal is a wideband pseudo random signal occupying the whole time-frequency（TF） plane,whereas the FM interference signal is well concentrated in the TF plane,a new method is proposed based on adaptive short-time Fourier transform（ASTFT） 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.