【作者】 朱中锐；

【导师】 杨德森；

【作者基本信息】 哈尔滨工程大学 ， 水声工程， 2013， 博士

【摘要】 矢量水听器的出现，突破了声纳设备获取水下声信号长期依靠标量声压水听器的限制，为我国声纳技术的发展开辟了新的途径。矢量水听器可以空间共点同步拾取声场一点处的声压和质点振速矢量，利用获取的声压和质点振速可在全空间对声源进行无模糊定向，且获得等价于四元声压阵声纳系统的检测性能，这种水声传感器的紧凑型配置方式为解决水下小尺度平台湿端布置空间受限的问题提供了很好的解决方案。矢量水听器还具有不依赖于声波频率的空间指向性，这个优点在水声系统低频化发展的趋势下显得尤为突出，能够使得基于矢量水听器的声纳系统具有更好的低频适应性。当利用多个矢量水听器组成声纳基阵时，能够将矢量水听器的抗噪能力和阵列系统的空间分辨能力有机结合起来，进一步提高声纳系统的性能，获得比相同数目的声压阵更好的性能；或者在相同的性能指标要求下，能够显著的减小阵元数目。矢量水听器的诸多优势使得这项技术已经成功应用于低噪声测量系统、海上浮标声纳、拖曳阵声纳等水声设备中。但是上述应用都是假设矢量水听器处于自由场条件下，当矢量水听器安装于水面船舶和水下航行器等载体时，由于载体障板声学散射的影响，会导致矢量水听器性能发挥受到极大影响。如何在水面和水下载体声障板条件下应用，并且使得矢量水听器可以取得海上声纳浮标设备那样的良好效果，成为急需解决的一个难题。本文以船舶上三型典型声纳设备声障板——矩形、圆柱形和球形障板为模型，研究上述三种障板声散射近场矢量特性以及相应障板条件下矢量信号处理方法。针对矩形障板，以工程实际中使用的弹性矩形空气腔障板为研究对象，探讨了弹性矩形空气腔障板水下声散射，将弹性矩形空气腔障板建模为无限大刚硬平幕中，镶嵌一块可以振动的板，板的两侧流体分别为水和空气，板的边缘满足简支边界条件。给出弹性矩形空气腔障板水下声散射声场的解析解，并且验证了该模型的合理性以及推导公式的正确性，在此基础上研究了弹性矩形空气腔障板水下声散射近场矢量特性。由于矩形空气腔障板声散射的声压场和质点振速场的表达式比较复杂，不利于后续的信号处理，将散射声场表示为反射系数刻画的简洁的模型，这样，就建立起反射系数所表征的矩形空气腔障板条件下矢量线阵的测量模型。基于该测量模型研究了矩形障板条件下矢量线阵阵列信号处理方法，在直接阵元域实现了声压和振速的相干信号处理。与相同阵型的声压阵相互比较的结果表明，矩形障板条件下矢量线阵仍然能够充分发挥矢量水听器的优点。针对圆柱形障板，考虑工程实际，采用密闭的圆柱形空气腔壳体作为圆柱形基阵的反声障板。首先研究有限长圆柱壳体水下声散射，在前人研究的基础上，采用弹性力学中的薄壳理论（Donnell方程）表述圆柱壳体运动，并在一定的近似假设下给出有限长圆柱空气腔壳体表面水下声散射声场的解析解，在此基础上研究了有限长圆柱空气腔壳体水下声散射近场矢量特性。在此基础上将传统的障板条件下标量圆弧阵的相位模态域信号处理方法引入圆柱形障板条件下的矢量圆阵，对远场平面波激起的圆柱形障板附近声场，将复杂的近场干涉图案分解为规则的相位模态域图案，提出了矢量圆阵声压振速相位模态域阵列信号处理方法，在相位模态域实现了声压和振速的相干处理，将矢量水听器的抗噪能力与圆阵阵列系统的分辨能力有机结合起来，同时将子空间类DOA(direction of arrival)估计算法和相位模态域阵列信号处理技术有机结合起来，从而将矢量水听器的适用范围扩展至圆柱形障板条件。本文还研究了球形障板条件下矢量水听器的应用。首先采用薄壳理论和分离变量法研究球形空气腔壳体水下声散射，重点研究空气腔球壳水下声散射近场矢量特性，在此基础上从球形障板条件下声矢量圆阵阵元域信号的表达式出发，利用声场分解理论，将阵元域信号表示为若干阶正交的相位模态，然后给出声压、径向振速和切向振速的预处理矩阵，利用预处理矩阵将声矢量圆阵阵元域信号变换到相位模态域，在相位模态域给出了协方差矩阵的生成方法，然后进行方位估计，实现了球形障板条件下声压和振速的相干处理，将矢量水听器的适用范围扩展至球形障板条件。本文设计了矩形空气腔障板三元矢量线阵和圆柱形空气腔障板八元矢量圆阵水声试验系统，开展了外场试验研究，试验结果和仿真结果符合得较好，验证了本文理论的正确性。为矩形空气腔障板和圆柱形空气腔障板条件下矢量水听器的工程应用提供了试验基础。更多还原

【Abstract】 The emergence of acoustic vector sensor, broke through the restrictions that measuringthe underwater acoustic signal for the sonar equipment has long relied on scalar pressuresensor, opens up a new way for the development of sonar technology. The acoustic vectorsensor is combined by omnidirectional pressure sensor and dipole particle velocity sensor,which co-locating and simultaneously measures acoustic pressure and all the three orthogonalcompotents of particle velocity in acoustic field. Using that information, it can obtain theintensity and direction of sources, and can have equivalent performance of a four elementssonar system with omnidirectional pressure sensor. This compact configuration of theacoustic sensors provides a very good solution to solve the problem of limited of the layoutspace of the small scale underwater platform. The directivity of acoustic vector sensor is notdependent on the frequency of sound. This advantage is particularly prominent in thelow-frequency trend of development of sonar systems. And it can make the sonar systemswhich base on the acoustic vector sensor have better low-frequency adaptability. The vectorsensor provides more information than a pressure sensor as it contains three dipole channelsin addition to a monopole channel. Hence, an array of N vector sensors can achieve betterperformance than a conventional array of N pressure sensors. Likewise, a given level ofperformance may be attained with fewer vector sensors. Due to these attractive characteristics,the acoustic vector sensor has been successfully applied to low-noise measurement system,marine sonar buoys, towed array sonar and other acoustic devices. These works have onlyconsidered the acoustic vector sensors in free space; however, when the acoustic vectorsensors are mounted on a ship, due to the scattering of the acoustic baffle, it will result in asignificant decline in the performance of the vector sensor. Therefore, how to use the acousticvector sensor in the presence of an acoustic baffle and obtain good performance as the marinesonar buoys have become urgent problems. In this paper, the three typical sonar baffles--rectangular, cylindrical and spherical baffle are taken as research objects, acoustic vectorcharacteristics of near fields scattered by the three typical sonar baffles as well as thecorresponding vector signal processing methods are studied.For the rectangular baffle, an elastic rectangular air chamber baffle which is usedcommonly in practical engineering is taked as research object. The elastic rectangular airchamber baffle is modeled as a baffled, simply supported plate. The both sides of the plate arewater and air respectively. The analytical expressions for the scattered pressure and particle velocity are derived. Then the rationality of the model and the correctness of the formula areverified. Calculations are presented for the scattered near fields of the pressure, the particlevelocity and the intensity. Because the expression of sound pressure field and particle velocityis quite complex, is not conducive to the signal processing, the scattering field were simplymodeled based on the reflection coefficient. In this way, we can establish a measurementmodel of vector sensor linear array with rectangular air chamber baffle based on the reflectioncoefficient. Based on this measurement model, vector signal processing methods for thevector sensor linear array with rectangular air chamber baffle is studied. Coherent signalprocessing of pressure and particle velocity is achieved in the direct element space.Simulation and experimental results show that the vector sensor linear array with rectangularair chamber baffle still can take full advantage of the vector sensor.Considering the engineering practice, a closed finite length cylindrical air chamber shellis used as a cylindrical baffle. Firstly, the acoustic scaterring from finite length cylindricalshell is studied. On the basis of previous studies, we use the elastic thin shell theory (Donnellequation) describe the motion of cylindrical shell, and under some approximation assumptionsanalytical expressions are derived for the total acoustic pressure field and the total particlevelocity field scattering from the cylindrical shell. The acoustic vector characteristics ofspatial distribution are discussed based on the analytical expressions. Phase modal domainsignal processing method for a traditional scalar circular array is introduced into the acousticvector sensor circular array mounted around a cylindrical baffle. The complex interferencepattern near the surface of cylindrical baffle, which is provoked by the far-field plane wave,can be decomposed into regular phase modal patterns. Then the modal vector-sensor arraysignal processing algorithm, which is based on the wavefield decomposition techniques, forthe acoustic vector sensor circular array mounted around the cylindrical baffle is proposed.Coherent signal processing of pressure and particle velocity is achieved in phase modal space.It is concluded that the vector sensor can be used under the condition of the cylindrical baffleand that the acoustic vector sensor circular array mounted around the cylindrical baffle canalso combine subspace DOA (direction of arrival) estimation algorithm with phase modalspace array signal processing technology. The scope of application of vector hydrophone isextended to the cylindrical baffle condition.The article also studied applications of vector sensor under the conditions of sphericalbaffle. Firstly, the analytic expressions for the scattered pressure and particle velocity arederived using the elastic thin shell theory. Calculations are presented for the scattered nearfields of the pressure, the particle velocity and the intensity. Based on the Wavefield decomposition techniques, the element domain signal were represented for some orderquadrature phase modes, and then gives the preconditioning matrix of the pressure, the radialvelocity and tangential velocity. The array signals are converted from element space to phasemodal space using the preconditioning matrix, and then estimate direction of arrival in phasemodal space. The algorithm is based on the principle of coherency between pressure andparticle velocity, which can suppress interference in isotropic noise field. The scope ofapplication of vector hydrophone is extended to the spherical baffle condition.Two experimental sonar systems, the three elements linear acoustic vector-sensor arraywith a rectangular air chamber baffle and the eight elements circular acoustic vector-sensorarray with cylindrical air chamber baffle, were designed to carry out the Songhua Lakeexperiment. The test results and the simulation results were in good agreement, to verify thecorrectness of the theory in this paper and provide the experimental basis for the engineeringapplication of acoustic vector-sensor with acoustic baffle.更多还原