超视距雷达中窄带干扰抑制技术研究

超视距雷达中,发射信号带宽的选择受到密集的大功率干扰的限制,很难找到较宽的且未被污染的干净频带,导致了很低的距离分辨力和信干噪比,较为理想的方法是在一定的带宽要求下抑制干扰.考虑到直接用凹口滤波零陷干扰时,脉冲压缩后副瓣迅速抬高,目标信号淹没在干扰的旁瓣之中,本文提出了抑制旁瓣干扰的投影算法和时域自适应对消方法.理论分析和仿真结果表明:投影法计算量小,副瓣得到一定的降低,但需要设计子带滤波器组,且引入了暂态响应;而自适应对消方法虽然计算量稍大,但通过自适应调整权值可很好地抑制掉旁瓣干扰,脉压后副瓣电平大大降低,有效地提高了目标检测能力.

Research on the Suppression Technology of Narrow-Band Interference in OTHR

In over-the-horizon radar (OTHR),the selection of transmitted bandwidth is limited by lots of crowded and powerful interference.It is difficult to find a broad and uncontaminated frequency band which results in low range resolution and signal-to-interference and noise ratio(SINR).A desired method is suppressing interference within a definite bandwidth.Considering the poor sidelobe of notch filtering method,in which target signal is masked in the sidelobes of interference,the projection algorithm(PA) and adaptive cancellation algorithm(ACA)are introduced.It follows that PA has the advantage of low complexity of computation and low sidelobe by designing sub band filter group though the temporal response will be introduced.By adjusting the weights,ACA can eliminate sidelobe interference effectively at the cost of heavy burden of computation.The sidelobe level of pulse compression was reduced greatly which will increase target detection probability effectively.