MIMO Radar Calibration Using Null Space Method

Angle estimation performance is highly sensitive to the phase and amplitude errors within the antenna array, which can arise from channel imbalances and mutual coupling between array elements. Large phase and amplitude errors can cause bad angle accuracy, high angular sidelobes, wrong estimation of number of targets, and even angle jumps, particularly in sparse array configurations. Typically, the phase and amplitude imperfections are compensated using a calibration matrix. This paper presents a null space method to calculate the calibration matrix with enhanced accuracy. The effectiveness of the null space method is verified by both simulation data and real radar data.