【作者】 张涵；

【导师】 连琏； 付斌；

【作者基本信息】 上海交通大学 ， 船舶与海洋结构物设计制造， 2011， 硕士

【摘要】 海洋对于人类的生存与发展具有极大的重要性。海洋作为资源的宝库是地球上尚未充分开发利用的最大领域,它在解决人类面临的人口、资源、环境等三大难题方面将发挥越来越大的作用。因此,自上世纪60,70年代以来,世界各国开始大规模向海洋进军,迄今海洋开发利用已经取得很大进展。现代海洋开发的一个显著特点,是开发规模和领域迅速扩大,海洋产业日益增多,特别是对于深海开发和海洋灾害监测技术的发展较快。不管是深海开发还是海洋灾害监测,对于水下目标的探测定位都是异常重要的。在海底勘探时需要有一定的定位系统配合,这些系统可以在局部海域对水下目标进行高精度的定位。水下定位系统有很多种,如短基线系统,超短基线系统,长基线系统,惯性导航系统以及组合的导航系统等等。但是现行的水下定位系统设备成本高、笨重不易装卸,数据处理复杂,实时性差定位范围有限,定位精度受障碍物影响大。并且,现行水下定位开发应用还需定位系统支持全海域的监测以及对水下未知目标的探测定位。本文首先从海洋开发的应用背景以及需要的高技术方面进行归纳研究,然后对于其中至关重要的水下定位技术方面着手,分析了水下定位技术的研究前景和现状,介绍了本文的两个重要原理无线传感器网络和声波传播衰减的研究现状和应用背景,然后阐述了本文的研究目的和研究意义,并对论文的主旨结构进行了简要叙述。其次,提出了基于传感器网络技术和声波衰减原理的水下未知声源定位技术,实现了无需载波、无需精密测量时间差的实时测距,从而大幅减低节点设备成本和功耗。简要叙述了整个系统的构成和具体的定位流程,阐述了不同水听器基阵结构的形状,对于已知声源定位技术进行了简要的分析,在此基础上,重点分析了未知声源定位相对与已知声源定位的数据处理方面的难点,并提出了基于FFT频谱分析的数据处理方法,然后提出了未知声源定位的数学模型和定位计算算法。再次,对于不同水听器基阵的拓扑结构,进行了数值仿真实验,分析了水面多径反射及噪声对于定位精度的影响。另外,提出了基于多个特征频率求平均值的修正方法,并对修正结果进行分析和阐述。最后,在上海交通大学深海实验水池进行了实验,验证了声波传播衰减原理应用于未知声源定位的可行性,并且分析其定位精度,运用多个特征频率的修正方法修正实验结果。本文中,我们提出了一个基于无线传感器网络和声波传播衰减的新方法,来对未知声源进行定位。我们采用理论分析,水池实验,数值仿真结合的方式来对在背景噪声和多径反射下未知声源的声压信息分析方法进行分析,并得到了传播衰减于距离的函数关系,为低成本水下定位技术发展奠定理论基础。更多还原

【Abstract】 Ocean is a place of great importance for the existence and development of mankind. As a treasure trove of marine resources, ocean is the biggest field that hasn’t yet been fully exploited on the earth, which ensures that it plays as a more and more important role in addressing tough issues as human population, resource and environment. Therefore, since 1960s and 1970s, many countries have started to march into the sea, which turned into today’s huge progress in ocean development and utilization. A notable feature of modern exploitation in marine is the rapid expansion in scale and area, the fast growing of marine industry, and especially the deep-sea technology as well as the marine disaster monitoring skills.Whether in deep-sea development or marine disaster monitoring, acoustic detection and localization is extremely important. The seabed exploration requires positioning system which can be used to locate the n position of the underwater target. Underwater positioning system has a lot of kinds, such as short baseline system, ultra-short baseline system, long baseline system, inertial navigation system and combinations of navigation system, etc. However, Current underwater positioning system equipment has many short comings: high cost, complex data processing, limited Positioning range, bad real-time identification and big influence by the obstacles. In addition, the current underwater positioning development application still needs positioning system that can realize marine monitoring and support the underwater detection and localization of unknown object. First of all, marine development application background and need of high technology was summarized. Then, the technical characters, application future and research situation of underwater positioning system in detail is illustrated. The paper introduces the current research and the application background of WSN and SPL, and expounds the purpose and significance of the research. At last the paper’s structure is also introduced briefly.Secondly, the new method, based on sensor networks and sound propagation loss, is applied to underwater unknown source localization. By using of this method, real-time ranging without carrier and precisely-measuring time is realized which thus greatly reduce the equipment cost and power consumption of nodes. Briefly the whole system structure and positioning process are described. Then, the paper made a brief analysis of different hydrophone arrays and known source positioning. On that basis, the paper emphatically introduces the complexity of the data processing in unknown source localization, proposes FFT frequency spectrum analysis for data processing, And then the mathematical model and localization algorithm has been put forward.Afterwards, the research performs the experimental study and the numerical simulation to the different hydrophone arrays .Numerical results and analysis validate the proposed indices and models. The influence of the multipath reflection and the hydrophone array on the location precision is analyzed. The averaged correction method based on multiple characteristic frequency is proposed and the corrected results analysis are described.In the end of paper,we has finished the tests in deep-sea tank of Shanghai Jiao tong university .In these tests, sound propagation loss principle has been applied to unknown sound source positioning to verify its feasibility and practicability. Moreover, correction method we gave is adopted to modify the data. The results show that the new method is well.In this paper, we put up forward a new method based on SPL to estimate the position of unknown acoustic source, and we carry on the research, using theoretical analysis and computer simulation, to analyze the acoustic pressure of underwater sound signal which is interfered by water background noise and multipath reflection. According to the results, we got functional relation between acoustic pressure attenuation of the unknown source and the propagation distance. Then we have done preliminary calculation and analysis in the accuracy of the unknown acoustic source localization, which provides theoretical basis for large scale and low cost acoustic positioning technology and offers a new approach for tracking the movement of complicated underwater source, such as the unknown sailing noise, underwater construction noise, biological noise, natural disasters noise.更多还原