Joint Estimation Of Multi-targets Parameters In Polarimetric MIMO Radar

In recent years, there has been increased investigation on multiple-input multiple-output (MIMO) radar, a new radar system. Unlike traditional phased radar, MIMO radar simultaneously launch a set of mutually orthogonal waveforms in transmit array, which can form multiple transmit and receive channels in space, thus enhance the degree of freedom system. In MIMO radar, signal detection and parameter estimation are two important research topics. For traditional beamforming in dealing with the spatial characteristics of coherent signal, the spatial focusing ability is greatly reduced and even fails in some extreme cases. In recent years, the study found that the signal polarization information can help to de-coherent of the received signals, can depict the target features, which is gaining more and more concerns.In this thesis, the bistatic MIMO radar is considered and targets in the space exhibit coherence properties (close in space position). Because the traditional algorithms(Capon, MUSIC, ESPRIT and Propagator) failed in this case, the polarization information is introduced into the signal model; then the algorithms for estimation DOA, DOD and Doppler frequency are deduced; finally the corresponding simulation analysis is given. All of the above work proved that the polarization information can improve the resolution of targets in some extent.Next, a novel algorithm, we called orthogonal parameters method (hereinafter abbreviated as OP method), was deduced. By joining a group of orthogonal parameters to coherent signal model, the proposed algorithm can detect the coherent signal polarization information, which combined with the propagator algorithm. The essence of this method is by joining a group of micro disturbances that make the space coherent signal keeping the spatial coherence characteristics, but highlight the polarization information of irrelevant features. Simulation results demonstrate that the performance improves greatly in terms of the spatial resolution of coherent signal due to the introduction of perturbation parameters.Based on the above research, we further consider the target scattering matrix, where also introduced the polarization information. According to the previous research, it is recognized that target scattering matrix has an inherent contact with the target’s structure, material, shape, posture, etc., namely, features of targets can be detected through characteristics of target scattering matrix, and this provides the basis for further analysis. We introduce the target scattering matrix to MIMO radar. Using the OP method, we give the joint estimations about the DOA, DOD, Doppler frequency and the parameters of target scattering matrix.All of the above theoretical derivation is performed through computer simulation experiments. A large number of simulation analyses have been done and various cases are verified. Simulation results show that the OP method which considers polarization information can improve the resolution of the system; moreover it can provide the basis for further research, for example, we can use the results to detect the material or the posture.