基于动态交替投影的失配滤波器快速设计算法

Fast Algorithm for Mismatched Filter Design Based on Dynamic Alternating Projection

雷达脉冲压缩处理中,通常需要使用匹配滤波器以获得最优的输出信噪比。然而,对于常用雷达波形,其匹配滤波器输出距离旁瓣较高,易产生目标遮蔽效应,而通过优化设计失配滤波器可以在牺牲一定输出信噪比的条件下有效抑制距离维旁瓣。另外,在实际应用中一般需要对系统失真进行周期性标校,进而根据经过系统失真后的雷达波形进行失配滤波器设计,所以需要高效率的失配滤波器设计算法。然而,现有的失配滤波器设计算法通常涉及矩阵求逆等复杂计算过程,其计算复杂度高且不利于硬件实现。本文提出一种基于动态交替投影的失配滤波器快速设计算法,可实现在峰值旁瓣值、积分旁瓣值、加权积分旁瓣值等优化准则下的距离维旁瓣抑制,且信噪比损失、主瓣展宽可控。本算法适用于多种脉冲压缩波形,算法过程仅需用到简单计算及快速傅里叶变换,适用于硬件的高效率设计与实现。

Pulse compression is usually achieved using a matched filter to obtain the best output signal-to-noise ratio(SNR).However,for commonly used radar waveforms,the output of matched filters has high range sidelobes,which can easily result in target masking effect.It is often desirable to accept a slight penalty in the SNR to suppress range sidelobes using an optimized mismatched filter(MMF).Moreover,MMFs should be designed based on the radar waveforms with system distortion,which needs to be periodically obtained from real radar systems.Hence,MMF algorithms should be efficient.However,complex calculations,such as matrix inversion,are usually needed in existing algorithms,the large amount of computation of which is not suitable for hardware implementation.In this paper,a fast algorithm for MMF design based on dynamic alternating projection is proposed,and range sidelobes can be effectively suppressed under peak sidelobe level(PSL),integrated sidelobe level(ISL)and weighted ISL(WISL)criteria with constrained loss of SNR and mainlobe broadening.The proposed algorithm can be applied to different types of radar waveforms.Moreover,only simple calculations and fast Fourier transform(FFT)are used in the proposed algorithm,which is very suitable for hardware implementation.