Study On The New Methods Of High-resolution Direction Finding Based On Bayesian Principle And Monte Carlo Method

High-resolution multi-source direction finding is always a hot research area in array signal processing. The breakthrough of this technique is greatly meaningful in many research fields such as sonar, radar, communication, biomedical engineering, geology and so on. Especially the underwater acoustics high-resolution multi-source direction finding technique is the key to underwater searching and ocean exploration. Sponsored and supported by the National natural Science Foundation, the Aviation Science Foundation as well as the National Pre-research Project, Bayesian high-resolution method is thoroughly studied and summarized in this thesis. The novel Bayesian high-resolution DOA estimator based on Gibbs sampling is given to improve the real-time performance of original Bayesian high-resolution DOA estimator. The new progresses and main results are summarized as follows:1. The performance of Bayesian high-resolution method is investigated and summarized comprehensively.Bayesian high-resolution method is introduced briefly. Its angular resolution ability under different SNR is summarized comprehensively. The highest resolution of Bayesian method is 1/18 bandwidth of the beam main lobe i n high SNR (20dB) and 1/3 bandwidth in low SNR (-lOdB). The effects on its performance by the factors such as sanpshots and number of array sensors are investigated and their relations are also qutitantively analyzed.2. A novel Bayesian high-resolution multi-source DOA estimator based on Gibbs sampling is proposed.To improve the real-time performance of Bayesian high-resolution method, a novel Bayesian high-resolution multi-source DOA estimator based on Gibbs sampling is proposed. On the basis of theoretical study, large amount of computer simulation and statistical analysis is conducted to investigate the perfomance of the new method. The research indicates that the new method not only contains the super performance of original Bayesian high-resolution method but also significantly reduces the computation quantity from 0(LK ) to 0(KxJxNs). And the new method can be successfully extended to the case of multiple sources.3. The new method and original Bayesian high-resolution DOA estimator are compared with other typical methods like MUSIC and MLE, and the superiority of the new method is revealed.The new method and original Bayesian method are compared with the other twomethods in the aspects like angular resolution ability, performance in low SNR. It is proved that the new method possesses better performance than MLE and MUSIC, especially in low SNR In the case of three sources, the simulation results show that the performance of new method is much more superior than MUSIC.