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.