Research Of MIMO Radar With Widely Separated Antennas Signal Level Multi-target Localization

Multiple-input multiple-output(MIMO) radar employs multiple transmit antennas to emit mutually orthogonal waveforms and multiple receive antennas. The MIMO radar with widely separated antennas ensures the independence between either two transmit-and-receive paths to jointly process the returned signals and observes the target from different angles simultaneously and thus providing both diversity gain and geometry gain and can mitigate the performance degradations caused by the radar cross-section fluctuations at the same time. As a result, the detection, localization and tracking performances are improved and thus the MIMO radar with widely separated antennas has drawn more and more attention from researchers.This thesis focuses on the multiple targets localization problem for MIMO radar with widely separated antennas by studying the multi-target joint detection and localization algorithm. The specific contributions are introduced as follows:1. Aiming at the localization for single target, the data level algorithm based on weighted least-squares method and the signal level algorithm based on parameter estimation have been studied and the performances of the two algorithms are compared based on theoretical analysis and simulation results.2. Aiming at the localization for multi-target, a signal level high dimensional method has been proposed, of which the main idea is to employ general maximum likelihood estimation to estimate the number and location of targets.3. Aiming at the curse of dimensionality of the high dimension method, two signal level joint detection and localization algorithms based on dimension reducing have been proposed. These two algorithms show little performance loss while significantly reduce the complexity compared with the high dimension method.4. Aiming at the theoretical performance analysis of the proposed algorithms, the Cram′er-Rao lower Bounds(CRLB) of the high dimension method and the dimension reducing method are derived. Simulation results are given to demonstrate the validity of the CRLB.The validity of all the proposed algorithms and performance analysis is proved by simulation results, which show that the proposed signal level multi-target localization algorithms have the ability to estimate the number and location of the targets with high accuracy.