Study On The Key Techniques Of Underwater Multiple Source Localization

Multiple source localization technique plays a very important role in sonar, radar, communication, marine resources exploitation, geologic exploration, national defense, biomedical engineering, etc. Aiming at the applications in engineering, the principles of parameter estimation are discussed comprehensively in this dissertation. Considering the characteristics of underwater detecting and tracking system, the key techniques of underwater multiple source localization are systematically studied by theoretical analysis, computer simulation and experiment in the water tank. The main results and achievements are summarized as follows:1. The performance of beamspace high-resolution direction-of-arrival (DOA) estimation is analyzed. A dense beamspace MUSIC (DBMUSIC) algorithm for the uniform linear array (ULA) is proposed. It is shown that the performance of DBMUSIC is superior to that of the original beamspace MUSIC (BMUSIC) in the low signal-to-noise ratio (SNR) case.2. The robustness of high-resolution DOA estimators in the elementspace and beamspace is investigated thoroughly. An error model of array is established. A novel class of weighted Toeplitz high-resolution DOA estimators based on the covariance matrix of ULA output is proposed, which can obviously improve the performance of high resolution in the presence of array errors. A simple and effective expression of weight coefficient is given. Moreover, the influence of weight coefficient to the performance of DOA estimators is discussed. Referring to different high-resolution approaches, the corresponding weighted Toeplitz MUSIC (TMUSIC) algorithm, weighted Toeplitz Mini-Norm (TMini-Norm) algorithm, weighted Toeplitz BMUSIC (TBMUSIC) algorithm and weighted Toeplitz DBMUSIC (TDBMUSIC) algorithm are presented respectively. It is demonstrated that the weighted Toeplitz high-resolution DOA estimators in the presence of array errors possess the properties of high robustness, well performance, and is easy to be implemented.3. Considering particular characteristics of multiple source localization, a novel and efficient ESPRIT-TDF algorithm of joint estimation of DOA andtime-delay is proposed. Within one single source echo, both DOA and time-delay can be estimated simultaneously by this algorithm via high-resolution rotational invariance technique and high-resolution time-delay frequency (TDF) technique. The ESPRIT-TDF algorithm has features of low computation, good precision, and high resolution both in DOA and time-delay. It is suitable for multiple source exact localization. Meanwhile, the performance of joint estimation of time-delay and frequency using the reduced interference distribution (RID) is analyzed comprehensively. It is demonstrated that RID has good performance in resolution and precision.4. Through experimental study, the correctness and efficiency of proposed algorithms are proved. A series of experiments by using the experimental system in the water tank for parameter estimation and source localization are conducted on DOA estimation, joint DOA and time-delay estimation, and joint time-frequency estimation. In the case of different parameters, the performance of the estimation algorithms is investigated, including beamforming, MUSIC, TMUSIC, Mini-Norm, TMini-Norm, BMUSIC, TBMUSIC, DBMUSIC, TDBMUSIC, ESPRIT-TDF, and RID. Experimental results are shown that the algorithms above are significant in the engineering applications.5. An analysis software system of multiple source localization is developed for the first time. This software system consists of more than 60 estimation algorithms for the source parameters (DOA, range and velocity), including conventional algorithms, high-resolution algorithms, and the proposed novel algorithms. It possesses several advantages, such as powerful processing and output functions, easy operation, and high error-tolerance. This software system can not only for investigating the performance of paramet...