基于时变滤波器的线性调频干扰抑制

LFM Interference Suppression Based on Time-variant Filter

为提高伪码调相脉冲多普勒引信抗线性调频(LFM)干扰性能,将基于分数阶傅里叶变换(FRFT)的自适应时变干扰抑制滤波器应用到伪码调相脉冲多普勒引信中,用来对LFM干扰进行抑制。干扰抑制的效果与LFM信号参数的估计精度有关,为解决计算量与估计精度的矛盾,采用先大步长、后小步长两步估计法。仿真结果表明自适应时变干扰抑制滤波器显著改善了伪码调相脉冲多普勒引信的相关输出。

In order to improve the anti-LFM （linear frequency modulation） interference performance of pseudorandom code phase-modulation and pulse-doppler combined fuze, adaptive time-variant interference suppressing filter based on FRFT （fractional fourier transform） is used to suppress LFM-interference in the combined fuze. The performance of interference suppression is related to the estimated accuracy of LFM signal parameters. In order to solve the contradiction between calculation amount and estimated accuracy of parameters, the method of two-step estimation is used which means firstly,a big step is used and then a small step is used. The simulation results show that the adaptive time-variant interference suppressing filter can suppress LFM-interference effectively and can improve the fuze correlation output obviously.