Study On Measurement Methods Of Target For MIMO Bistatic Radar

MIMO bistatic radar is a new conception in recent years, and the research for its theory and technique has become one of hot problem in the domain of radar. Since it has both characteristics of MIMO technique and the bistatic radar, the MIMO bistatic radar is provided with the potential ability of the anti-reconnaissance,anti-jamming, anti-stealth and anti-radiation attack, and can be widely found application in the future radar. This dissertation is devoted to do researching in-depth on the target measurement theory and several key techniques in MIMO bistatic radar. The main contributions can be summarized as follows.1,In order to solve the problem in the algorithm of transmission diversity smoothing (TDS), an algorithm of virtual subarrays dual smoothing (VSDS) is proposed. First the smoothing processing of the echo signals in the virtual subarrays is carried out, then the smoothing processing between the virtual subarrays is done, finally the multitarget directions are estimated by the eigenstructure-based methods. The theoretical analysis and simulation results show that the performance of the proposed method is better than the TDS algorithm, and its maximum estimated targets can break through the limitation of the number of transmitters.2,A multitargets signal model of MIMO bistatic radar is set up and a joint angles-Doppler frequencies estimation algorithm for multitargets is proposed. In the algorithm, the virtual array data of multitarget echoes in MIMO receivers are firstly decorrelated, and a special matrix based on the propagation operator is then constructed, finally the joint estimation of the DODs, DOAs and Doppler frequencies can be obtained by the corresponding relationships between the eigenvalues or eigenvectors and the estimated parameters. The proposed algorithm does not need the multi-dimensional nonlinear peak search, and do only an eigenvalue decomposition, and the estimated parameters of the targets can be paired automatically. The correctness and effectiveness of the proposed method are verified with the computer simulation.3,In order to estimation the multitargets in space, the signal model for L shaped MIMO bistatic radar is set up and a novel method of multitarget localization in L shaped MIMO bistatic radar is proposed. Based on four angles information involved in L shaped receiving array from target to transmiter and receiver, the joint estimation algorithm for four angles of multitarget can be obtained by the following steps: decorrelating the array data of received echoes first, then constructing estimation matrix based on the DOA matrix method, finally using the given relationship between the eigenvalue and the estimated parameters. As a result, the multitarget localization in three dimensions is achieved in the bistatic radar. The proposed algorithm does not refer to multi-dimensional nonlinear peak search, and need only once eigenvalue decomposition, so that the computed load of the algorithm is low, and the estimated parameters of the targets can be paired automatically. The correctness and effectiveness of the proposed method are verified with the computer simulation.4,In order to measure the range, angle, and Doppler frequency of the target without any synchronization in the bistatic radar, a novel complete parameter estimation method based on separability of a pair of LFM signal is presented. The Doppler frequency is measured by the time difference between two peak positions corresponding to the positive and the negative LFM return signal respectively. DODs and DOAs of the target are estimated by the information involved in the returned MIMO signals. The target position can be located in the presence of the estimated DODs, DOAs and the signal delay difference between the echo and the directive wave signal in MIMO bistatic radar. The correctness and effectiveness of the proposed method are verified by the computer simulation. In order to implement in engineering, a novel complete parameter estimation method with single transmitting antenna for bstatic radar is presented. With this method the target parameters can be measured without any time, angle and frequency synchronization between transmitter and receiver.5,The transmitting-receiving signal model is set up and the expression of transmitting-receiving equivalent pattern has been derived. The restriction of set of transmitting signal and an example are presented. A method with SEA-MPPSO algorithm to designe the transmitting-receiving equivalent pattern has been proposed. The computer simulation results testify the validity of the method.6,In order to increase the anti-jamming ability of MIMO bistatic radar, the adaptive algorithms for beamforming with criterion of MIMO maximum signal to interference and noise ratio (MIMO-MSINR), MIMO minimum mean square error (MIMO-MMSE),MIMO minimum variance distortionless response (MIMO-MVDR) have been presented. The formula of three algorithms are derived and the steps are also presented. The simulation results show that the jamming gap in the pattern can be effectively formed and the anti-jamming ablility evidently improved by the proposed algorithms.