Research On Microwave Correlated Sparse Imaging Of Moving Target

Microwave correlated imaging method based on space-time stochastic radiation field is a novel imaging method. The space-time stochastic radiation field is generated by array antennas which transmit group-orthogonal and time-independence waveforms. After space-time stochastic radiation field interaction with the targets, incoherent observation echo which carries the information of targets at different time can obtained. High resolution radar image of the targets can be obtained by association processing of the received echo and the space-time stochastic radiation field.In this thesis, non-cooperative moving targets are taken as the research object which is on the basis of microwave correlated imaging method based on space-time stochastic radiation field. The theory of compressed sensing will be applied to microwave correlated imaging by using spatial sparsity of the targets. Firstly, the target motion is estimated, and the radiation field matrix is compensated. Finally, high resolution radar image of the non-cooperative moving targets can be obtained by association processing of accurate radiation field and the echo.Firstly, this thesis makes a model of microwave correlated imaging of the moving targets, and makes a reasonable approximation for the high speed moving targets. Because we mesh the imaging scene in the model, inevitably, so it brings off-grid problem. Therefore, this thesis analyzes the effect of off-grid targets on the imaging results and target velocity estimation, and puts forward an off-gird correction method. The numerical simulations illustrate effectiveness of the algorithm on off-grid correction.Secondly, the research on the microwave correlated imaging of moving target with constant velocity is studied, and the effect of the target motion on the imaging results is analyzed. For eliminating the influence of the target motion, this thesis provides two ideas:1) Firstly, the velocity of the moving target is estimated, and the radiation field matrix is compensated by estimated velocity. Finally, it obtains the target image by the correlation processing.2) It imaging and estimate at same time, which through alternating update imaging results and target velocity. Finally, the target estimated velocity and target image can be obtained. The feasibility of the two ideas is proved by the simulation experiments, and the results show that the proposed method can accurately estimate the velocity of the moving targets.Finally, based on the study of the microwave correlated imaging of moving target with constant velocity, a reasonable approximation is made for the high-speed moving target. In view of microwave correlated imaging method of the high speed moving target, and we put forward two solutions in this thesis:1) a large number of statistical list of the target motion state can be obtain, then quickly searching within the scope of target velocity and acceleration according to certain standard or fitness, we will get the optimal observation matrix for imaging.2) Alternative target velocity estimation and acceleration information is solved. The simulation results show that the method can improve the accuracy rating of radar imaging for high-speed moving target.