基于自适应脉冲压缩-Capon滤波器的MIMO阵列雷达CFAR检测器

A CFAR detector for MIMO array radar based on adaptive pulse compression-Capon filter

针对强杂波背景和有限训练样本数量条件下采用脉内编码压缩波形的MIMO阵列雷达目标检测问题,借鉴自适应波束形成技术中Capon最小功率估计器的相干源信号对消思想,提出了自适应脉冲压缩—Capon滤波器(简记为APC-Capon滤波器),并基于此滤波器的输出设计了一种CFAR检测器.理论分析和数值仿真均表明,该滤波器能够在执行非迭代自适应脉冲压缩并抑制各发射波形自相关距离旁瓣和互相关干扰的同时,实现杂波信号对消,即杂波抑制功能.检测性能仿真表明,尽管相同尺寸参数(包括发射阵元数、接收阵元数、脉冲编码位数、相参脉冲个数)条件下,所设计的基于APC-Capon滤波技术的CFAR检测器的性能不如训练样本数量充足时基于"匹配滤波+样本矩阵求逆(SMI)"技术的AMF检测器,但是随着尺寸参数的适当增大,前者的检测性能将逐渐超过后者在较小尺寸参数时的检测性能,且不显著增加计算复杂度和训练样本数量,而后者则因大尺寸参数时对计算复杂度和训练样本数量的需求过高而在实际中难以实现.仿真还表明,APC-Capon滤波器及其相应的CFAR检测器对发射波形的相关性(包括自相关性能和互相关性能)有一定的依赖性,但随着发射波形数量的增加,这种依赖性逐渐降低.

Under the condition of strong clutter and finite training samples,a novel CFAR detector based on the proposed adaptive pulse compression-Capon filter （APC-Capon filter） is presented for MIMO array radar which transmits intrapulse coded waveforms.Both theoretical analysis and numerical simulations show that the proposed APC-Capon filter can utilize the non-reiterative adaptive pulse compression technique to alleviate both range sidelobes and mutual interference;at the same time it also can borrows ideas from the coherent signals cancellation of adaptive beamforming to perform clutter suppression.The detection performance simulations show that,with the same size parameters （including code length and the numbers of transmitter elements,receiver elements as well as pulses）,the proposed CFAR detector is inferior to the adaptive matched filter （AMF） detector.But as the size parameters increase,the proposed CFAR detector will gradually outperform the AMF detector with smaller size parameters,and more importantly,unlike the AMF detector which has a lot of difficulties in performing due to the inordinate demands for the computational complexity and training sample size,this demands of the proposed CFAR detector will not significantly increase.The simulations also show that,the correlation properties of these intrapulse coded waveforms have certain effect on the APC-Capon filter and its corresponding CFAR detector.But fortunately,the effect will decrease as the number of intrapulse coded waveforms increases.