一种MIMO雷达更窄主瓣波束形成方法

摘要

介绍了一种获得更窄主瓣虚拟收发波束的方法。该方法通过天线阵元发射正交编码的波形，然后在接收端对回波信号进行处理。MIMO雷达由于靠稀疏阵列避免旁瓣的不利影响，所以可提高角分辨率和多普勒分辨率。但受到如空间、成本或者其他实际因素的限制，须将阵列布置成紧凑阵列，而紧凑阵列对低速目标检测效果较差。通过提出的加窗方式，紧凑阵列利用虚拟收发波束形成可获得更窄的主波束，提高对低速目标的检测效果。通过仿真验证，对归一化频率为0.0625的低速目标，信干噪比提升系数(SINR IF)约提升7.3 dB。%An innovative approach is introduced to form narrower mainlobe of virtual transmitting-receiving beamforming by transmitting orthogonal coding waveforms from the antenna elements and digitally processing their echoes at the receiver. The benefits such as increasing angle resolution and increasing Doppler resolution of MIMO radar mainly depend on the sparse arrays without the adverse effects of sidelobes. However, due to the actual limitation, such as room limitation for airborne, cost or other factors, we have to set the array in dense arrays configuration which is not good at detecting slow moving target. With the proposed amplitude taper approach, a narrower main beam can be achieved with dense arrays configuration after virtual transmitting-receiving beamforming and therefore the performance of detecting slow moving target is improved. Simulation result shows that for the normalized Doppler frequency 0.062 5, i.e., slow moving target, the signal to interference and noise improvement factor (SINR IF) is increased about 7.3 dB.