【作者】 黄益旺；

【导师】 杨士莪；

【作者基本信息】 哈尔滨工程大学 ， 水声工程， 2002， 硕士

【摘要】 近年来，随着水声技术的不断发展，匹配场处理技术在声源定位中得到了广泛应用，已经成为水声信号处理的重要手段之一。然而，海洋环境是极其复杂的，解算三维声场还存在许多困难，目前为止仍未找到一种有效的计算三维声场的快速方法。传统的声源定位处理器有不少，如线性处理器、最小方差处理器、匹配模处理器等等几十种，基本上都是基于声压场进行的信号处理。而声压是一个随机量，幅度和相位存在起伏，单次测量或少量有限次测量不能完整表达声场特性，这就很难准确进行匹配场声源定位，其精度得不到保证。之所以选择声传播时间的原因是：噪声容限可以得到提高，并且传播时间的计算可以不考虑声压的信息，从而降低了对环境模型失配的敏感性；相位的起伏也可通过到达包络的群延时来消除；传播时间是介质声速分布的伪线性函数并且传播时间的起伏远小于声压的起伏。综合以上分析，本文尝试了一种新的方法—声传播时延的匹配场声源定位，即运用最早到达的声信号在相邻基元上的时延作匹配场处理。 文中构造了两类代价函数，第一类代价函数基于相邻基元的传播时延，第二类代价函数基于声传播时间。文中运用该函数分别对海底深度、接收基阵位置和声速分布三种失配情况进行计算机模拟研究。仿真结果表明，第一类代价函数对海底深度和基阵倾斜失配是敏感的，对声速失配却不敏感，并且能够获得较高的深度定位精度；第二类代价函数对三种失配都不敏感，只是深度分辨率较低。为了克服代价函数对失配的敏感性，可采用提高时延估计精度和模型计算精度的方法。当两个条件满足时，敏感性得到极大的抑制并获得了较高的距离和深度估计精度。文中最后运用实验数据实现了匹配场声源定位。计算结果表明，基于声传播时延的匹配场定位对声速分布失配是不敏感的。虽然接收基阵位置倾斜和海洋深度误差对匹配场处理影响较大，但只要选择适当的代价函数，可以得到克服。 从仿真和实验数据处理的结果分析，声传播时延匹配场声源定位是行之．哈尔滨工程大学硕士学位论文 一 有效的方法。而且声线的寻找具有简单，精度高等特点。特别是射线理论对． 解三维声场尤为方便，它将有望实现三维声场的快速计算和声场的反演，达 到海详环境的监测目的。更多还原

【Abstract】 Reeenly, with the develOPment of underwater acouStic technology, matchedfield processing tecboques have been widely used in source localiZation andbecome one of the most boortan methods of acoustical signal processing. Whleocean environmeni is ven’ complex. there are many difficulties in solving three-dimensionaI sound field, till now we still did not get an efficient method to solvethis problem. Traditional matched field processors such as linear processor.minimal variance processor, matched mode processor and so on are almost basedon the processing of sound pressure, it is well Anown tha sound pressure is atime-vaping qMity. its arnplit’Ude and phase preserve peotation, singlemeasurement or limited measurements couldn’t present the real character of soundfield, so it will be more difficult to localize a source by matched field processingor get high accuracy of source localiZaion. The reasons focusing only on raytravel times are’ noise tOlerance could be enhanced and the sensitivity to theenvironment model mismatch may be reduced by neglecting amplitudeinformation; phase ambiguity is eliminated by employing the grouP delay ofarriving wave packets; travel times are pseudo-linear functions of sound speedprofiles of the medium, and the pertUrbation of ray travel time is much smallerthan sound pressure’s. Wth the above analysis of ray travel times, a new methodof source localiZation based on ray travel tirne is presented in Ans dissendion.There are tWo ldnds of cost functions in the thesis, the first is based on theray travel time delay of the adjacent hydrophones; the second is directly based oneq travel times. Under these fimctions, mismatch of ocean dePth, receiverlocation and sound sPeed profile have been simulated resPectively. DifferentresultS specify that the first kind of cost function is sensitive to the mismatch ofocean dePth and receiver location, but is insensitive to sound speed profile’s%$jaI8x9@t$M&zmismatch and has high accuracy of depth localiZaion; the second kind of costfimction is insensitive to all three kinds of mismatch, but its resolution of depth isvery low ln order to overcome the cost function’s sensitivity to mismatch,improvemeDt of the accuracy of time delay estimation and model calculation maybe adopted, when both conditions are reached, the sensitivity wiIl be greatlyreduced and the resolution of range and depth will be imProved at the same time.Finally the above results discussed are verified by source localiZaion usingexperimental data. Results rectify that matched field processing based on raytravel time delay is insensitive to the mismatch of sound speed proflle, althoughthe mismatch of ocean bottom depth and receiver location is bad to matched fieldprocessing, different forms of cost fimctions could decline the sensitivity.After the simulation analysis and experiment data processing, we couldconclude tha the inversion method of ray travel time is feasible to sotircelocaliZaion. Ray tracing is very simple and fast, and has high accuracy. Besidesthat ray theory is helpful to calculate three-dimensional sound field, and theinversion of sound field could be finished quickly enough to realize the detectionof ocean environment in wide area.更多还原