OFDM-MIMO雷达低空目标探测性能研究

针对低空多径效应和地杂波复合作用导致的低空目标探测性能下降, 利用正交频分复用(Orthogonal Frequency Division Multiplexing, OFDM)-多输入多输出(Multiple-Input Multiple-Output, MIMO)雷达的空间和频率分集特性提高低空目标探测性能.在建立正交频分复用-线性调频发射信号模型、多径效应模型和基于对称阿尔法稳定分布的地杂波模型基础上, 得出了OFDM-MIMO雷达接收信号模型.采用匹配滤波器恢复发射-接收天线对信号, 通过接收信号融合实现参差补偿, 减小了接收信号能量的深度衰减和剧烈起伏.仿真算例表明OFDM-MIMO雷达能够有效减小回波信号剧烈起伏和杂波对目标探测的影响, 实现多径干扰和杂波背景下对低空目标的稳定探测.

Low altitude target detection performance for OFDM-MIMO radar

Aiming at the low altitude target detection performance decline caused by the compound effect of low altitude multipath effect and ground clutter,the spatial and frequency diversity characters of the orthogonal frequency division multiplexing (OFDM)multiple-input multiple-output (MIMO)radar are used to improve the detection performance.Based on the establishment of the orthogonal frequency divi-sion multiplexing linear frequency modulation (OFDM-LFM)transmitting signal model,the multipath effect model and the ground clutter model based on symmetric alpha stable distribution,the spatial and fre-quency diversity character of OFDM-MIMO radar are analyzed and the compound received signal model is established.The matched filter is used to recover the signal from each transmitting-receiving pair.The signals are combined to realize the compensation irregularly,so as to avoid the deep energy depression and the severe fluctuation of the received signal.The simulation results show that the OFDM-MIMO radar can effectively reduce the effect on target detection caused by the severe fluctuation and the clutter of the re-ceived signals,and as a result,the stable detection is realized under multipath and clutter background.