Research And Implementation On Real-time Target Detecting With Towed Line Array

As the development of modern ocean technology, the radiated noise of warship and submarines is getting lower and lower, in order to meet the challenges of quite submarine, the navy will focus on the development of towed line array sonar in the future. Since the towed line array sonar is far away from the noise platform and it has a small blind area of detection, now the towed line array sonar has been widely used in the field of acoustic and it has also played an important role in the field of national defense and military. According to the development trend in the future, research on automatic passive detection has very important theoretical and practical value. This paper mainly studied on the key technologies of automatic passive detection for towed line array sonar, providing some theoretical support and engineering innovation for the development of towed line array sonar.In this thesis, According to the combination of the current development status of the towed line array sonar in our country and abroad as well as the development trend in the future, we have studied the current demand for development of the towed line array sonar and the problems we have meet, and at the same time we have a generality summary of some of the key technologies. After that, the passive Direction-Of-Arrivals(DOA) estimation、self-decision and multi-target tracking has been studied on the basis and formed a completely theoretical system of passive detection.Firstly several conventional beam forming algorithms were outlined in this paper, then we also introduced the adaptive beam forming algorithm, in order to solve the problem of computing excessive, we proposed an improved algorithm: the Sub-Array MVDR algorithm, also we have a simulation in order to verify these algorithms and compare their computation. According to the beam form result, we have a research on the automatic target judgment and detection, in order to meet the command of the towed line array sonar, two tracking algorithm were proposed(multi-target automatic tracking algorithm and manual intervention target tracking algorithm). At last, with the real hardware platform, we build a completely physical platform and implement these algorithms on the platform, obtaining a stable orientation information and continuous tracking of the target. After the complement of the design and development of hardware and software system, we carried out a lake test and ocean test in the Qian Dao Lake and East Sea to estimate the quality of the system.After the lake test and ocean test, the quality of the towed line array sonar system has been verified, the performance meet the demands. Under the circumstance of real-time processing system, the towed line array sonar equipments got the right DOA and exactly multi-target tracking and output display, the experiments achieved good results.