距离高分辨多输入多输出(multiple input multiple output,MIMO)雷达体制下,目标回波可能跨越多个距离单元,因此要求发射信号在主瓣附近具有较低的自相关旁瓣和互相关。针对这一问题,提出了一种基于遗传算法的类零相关多相码设计方法。该方法选择具有零相关特性的零相关码集为初始群体,然后针对零相关码的特性,对遗传算法的交叉和变异操作进行了优化设计。通过把相关信号能量向远离主瓣的区域挤压,获得的多相码在主瓣附近具有较低的自相关旁瓣和互相关。最后,计算机仿真验证了该方法的有效性。
Target echoes always span several range bins when high range resolution multiple input multiple output (MIMO) radar systems are employed. Hence it is expected that the transmitted signal has lower auto- and cross-correlative sidelobes near mainlobes. A novel approach to design zero correlation zone (ZCZ) like polyphase codes based on genetic algorithm is proposed. The proposed method selects the ZCZ sequence set as initial population and optimizes the crossover and mutation operations according to the characteristics of the ZCZ sequence set. With correlated signals energy being pushed far from the mainlobe, the designed polyphase code has lower auto-and cross-correlative sidelobes near the mainlobe. Finally, the validity of the algorithm is proved by simulation.