双基地多输入多输出虚拟阵列的稳健低旁瓣波束优化技术

双基地多输入多输出(MIMO)系统需要对目标的波达角和波离角进行二维估计,针对高分辨算法中阵列协方差矩阵处理运算量大以及估计性能对阵列流形失配敏感的缺陷,提出了一种基于二阶锥规划的抗阵列流形失配的双基地MIMO虚拟阵列波束优化算法.该方法利用MIMO的波形分集技术与双基地的目标定位解算,通过波达角和波离角在双基地定位椭圆上的对应关系,将双基地MIMO的二维合成方向矢量转化为一维的虚拟阵列流形,并证明了双基地MIMO虚拟阵列的波束图等效为发射波束图在接收阵角度域上的响应和接收波束图的合成.在优化波束图旁瓣的同时,该算法兼顾了固定方向上的相干干扰抑制,并提高了双基地MIMO虚拟阵列波束优化抗阵列流形失配的能力.通过波束图和方位谱优化的仿真分析和水池试验,验证了算法的有效性.

Optimizations for robust low sidelobe beamforming of bistatic multiple-input multiple-output virtual array

Two-dimensional estimation for direction of arrival and direction of departure is required in the target location of bistatic multiple-input multiple-output (MIMO) system. In view of the huge calculation of array covariance matrix processing and the sensitivity to the array manifold mismatch, a beam optimization algorithm which can resist array manifold mismatch is proposed based on the virtual array of bistatic MIMO. Optimization for beam pattern through the second-order cone programming is used in the algorithm. The waveform diversity technology and location of bistatic system are combined. The relationship between direction of arrival at and direction of departure from the ellipse locating line is used to convert the two-dimensional synthesis direction vector into one-dimensional virtual array manifold. It is proved that the beam pattern of virtual array manifold transformed in bistatic MIMO can be equivalent to the combination of the beam pattern of transmitting array mapping on the receiving array angle domain and the beam pattern of receiving array. The algorithm can not only control the side lobe and null the beam pattern but also improve the ability to resist array manifold mismatch. The validity of the method is verified by the computer simulation of the optimized beam pattern and spectrum.
Keywords： bistatic MIMO waveform diversity virtual array second-order cone programming