基于CLEAN思想的互补码信号脉冲压缩算法

CLEAN Concept Based Pulse Compression Algorithm for Complementary Code Signal

互补码信号具有理想的零旁瓣非周期自相关函数,特别适用于高频地波雷达。然而高频地波雷达常采用高占空比波形,近距离目标回波遮挡严重,遮挡时原互补码不再互补,脉压旁瓣很高。针对这一问题,提出基于CLEAN算法思想的互补码脉冲压缩方法,该算法利用互补码的子码互补特性,在不同遮挡程度使用不同长度的子码作为脉压系数;同时,引入了CLEAN算法的思想,由远距离段至近距离段依次进行脉压和CLEAN操作,在保留互补码零旁瓣特性的同时消除了不同子码段之间的相关性造成的距离栅瓣。多目标环境下的计算机仿真实验表明,这种算法在距离盲区内保持了互补码的零旁瓣特性,且无距离栅瓣。

The complementary code signal has an ideal zero sidelobe aperiodic autocorrelation function,which is highly applicable for high frequency ground wave radar.However,high frequency ground wave radar often adopts high duty-cycle waveform,and the close-range target echo is severely blocked.When this happens,the original complementary codes are no longer complementary,resulting in a high sidelobe level at the pulse compression output.Aiming at this problem,a complementary code pulse compression method based on CLEAN algorithm is proposed.This algorithm utilizes the subcode complementarity of complementary codes and uses subcodes of various lengths as pulse compression coefficients in scenarios of different blocking degrees.Meanwhile,the concept of the CLEAN algorithm is introduced here and pulse compression is processed from the far segments to the close segments with CLEAN operation accompanied so as to remain the zero sidelobe characteristics of complementary code and avoid the range grating lobes caused by the correlation between different subcode segments simultaneously.Computer simulation experiment of a multi-target environment shows that this algorithm maintains the zero sidelobe characteristics of the complementary code in the blind zone and has no distance grating lobe.