Angle Estimation And Array Calibration In Bistatic MIMO Radar

MIMO(Multiple Input Multiple Output) radar is a new type of radar system based on MIMO communication technology; it has better angle estimation performance than traditional phased array radar. However, array errors like unknown mutual coupling or gain-phase error which exist in practice severely affects the performance of DOA and DOD estimation. According to the non-ideal array conditions, this paper studies the angle estimation and array calibration of MIMO radar. The major researches are as follows:DOA and DOD estimation of bistatic MIMO radar with unknown mutual coupling is researched. An algorithm based on ESPRIT method for estimating DOA and DOD of bistatic MIMO radar is proposed. The new method can estimate the DOA and DOD accurately by utilizing the strip feature of mutual coupling matrix of uniform linear array(ULA) and the structural properties of antenna array matrix. The proposed method has the following advantages: free of search, automatic paired angles, small amount of calculation and stable performance in low SNR environment.Moreover, the proposed method has better DOA and DOD estimation performance than the original ESPRIT method under the ideal array conditions when the mutual coupling freedom is small. Simulation results illustrate the feasibility and correctness of the proposed method.DOA estimation and gain-phase error calibration of ULA array with gain-phase error is researched first. An algorithm based on a recursive rank-reduction(RARE)method for estimating DOA and calibrating gain-phase coefficients of UAL array is proposed. The new algorithm implements the joint estimation of gain-phase coefficients by using a recursive method to accumulate the estimated DOA information, which guarantees the estimated gain-phase coefficients being unique so as to improve the stability of gain-phase coefficients estimation performance. Another advantage obtained from the additional gain-phase coefficients uniqueness is that the performance of DOA estimation will be greatly enhanced, especially in low SNR environment. And then, angle estimation and gain-phase error calibration of bistaticMIMO radar with gain-phase error is researched. An algorithm based on a recursive RARE method for angle estimating and gain-phase coefficients calibrating of bistatic MIMO radar is proposed. The new method reconstructs the received data for estimating angles and gain-phase coefficients accurately by utilizing the similarity of the signal model between the traditional phased array radar and bistatic MIMO radar.The proposed method has the following advantages: one dimension search, small amount of calculation and stable performance in low SNR environment. Simulation results illustrate the feasibility and correctness of the proposed method.