非因果滤波器归一化最小均方误差对消算法

The NLMS Adaptive Cancellation Algorithm of Non-causal Filter

在利用外部辐射源的无源雷达中,强直达波和多径干扰会掩盖微弱的目标回波信号,严重影响目标的检测,因此提出基于数字非因果滤波器的归一化最小均方误差对消算法。该算法利用直达波相对于参考信号具有非因果系统响应的特点,在传统自适应对消技术的基础上,通过增加部分非因果的滤波网络实现了最小均方误差准则下的自适应杂波抑制。基于数字广播的仿真结果表明,本文提出的方法不仅能够有效消除直达波和多径干扰对检测目标回波的影响,同时还能够获得目标的方位信息。

When an passive radar being used with external radiation source, the existence of strong direct signal and multipath signal will mask the weak target echo and severely affect the detection result of target. A non- causal adaptive cancellation algorithm was proposed in this paper. The direct waves had the characteristics of non-causal system response to the reference signal, based on which, adaptive clutter rejection under the least mean squares （LMS） error was achieved by increasing the part of the non-causal filter network on the basis of traditional adaptive cancellation technology. Simulation based on frequency modulation signal showed that the proposed method not only removed influence of strong direct signal and multipath on target detection, but also acquired the DOA of target.