基于改进变步长自适应滤波的密集假目标干扰抑制方法

Dense False-target Jamming Suppression Method Based on Improved Variable Step Size Adaptive Filtering

提出了一种基于改进变步长自适应滤波的密集假目标干扰抑制方法。该方法首先采用stretch去斜处理,消去信号的二次项,并在频域上分离目标回波与干扰,从而得到频率不同的信号分量;然后用基于类箕舌线函数的变步长自适应滤波方法,对stretch处理后的回波信号滤波;最后对消密集假目标干扰,将对消后的信号作逆stretch处理恢复目标回波。所提出的类箕舌线函数调节自适应滤波方法中的步长,能有效地抑制距离目标回波较近的假目标干扰。仿真结果表明,改进变步长自适应滤波方法在目标回波与干扰时延差较小时,也可有效地对回波信号滤波,干扰对消效果明显;与基于定步长的滤波方法相比,所提方法在信干比较低的环境下仍具有良好的鲁棒性,并能有效抑制密集假目标干扰。

This paper proposes a dense false target jamming suppression method based on improved variable step size adaptive filtering. Firstly, the stretch de-chirping technique is utilized to eliminate the quadratic term of the signal,and the target echo and jamming can be separated in the frequency domain,thus signal components with different frequencies could be obtained. Next, the variable step size adaptive filtering method based on Versiera-like function is applied to filter the stretch processed echo signal. Finally, the dense false target jamming is eliminated and the target echo is recovered through the application of inverse stretch processing to the eliminated signals. The pres- ented adaptive filtering method based on Versiera-like function is applied to regulate the step size, which can effectively suppress the false target jamming which is close to the target echo. Simulation results show that the improved variable step size adaptive filtering method can effectively filter the echo signal and eliminate the jamming evidently when the time delay difference between the jam- ming and target echo is very small. Compared with the fixed step size filtering method, the proposed method still has a good robustness in the environment of low signal-to jamming ratio,and can effectively suppress the dense false target jamming.