基于矢量水听器的高指向性二阶水听器的研究

发布时间：2018-08-12 11:37

【摘要】：水下中小型测量平台是对水面和水下目标进行探测和定位的常用装备,这类平台的布阵空间狭小,不适合安装大孔径的水声传感器阵列,单矢量水听器在平台中的应用对提高平台的性能起到了良好的作用,但它的波束角较大,这种钝指向性在对目标定位的过程中难以获得较高的方位分辨率,对于多个距离较近的目标则更加难以区分,因此在中小型测量平台上仍然需要继续研发指向性更为锐化的高指向性水听器提升平台性能。高指向性二阶水听器是继矢量水听器之后一种新型水声传感器,相对于矢量水听器而言,二阶水听器具有更为锐化的四极子指向性,它的突出特点是具备测量声场中二阶张量的能力,因此开展针对高指向性二阶水听器的物理基础性研究和工程研究都是十分必要的。本文首先对高指向性二阶水听器的基础理论进行研究。利用张量的概念讨论水声物理问题,从声压分解理论入手研究二阶水听器测量的各阶张量,探讨流体声场中质点振速和振速梯度的物理意义,说明振速梯度张量与目前声学常用物理量的联系。理论分析证明了声场中流体微团内各点的声压不均匀性是导致流体微团发生运动的根本原因,质点振速可以描述流体微团的平移运动,振速梯度描述流体微团的变形和转动。从单通道指向性和多通道组合指向性两个方面分析了二阶水听器的指向性性能,并与矢量水听器的同类性能作比较,理论分析表明二阶水听器四极子指向性的波束宽度小于矢量水听器的偶极子指向性波束宽度,将两类水听器的同类组合指向性的波束宽度比较,证明二阶水听器的指向性性能优于矢量水听器。本文针对高指向性二阶水听器的设计理论进行研究。讨论二阶水听器的测量原理,给出二阶水听器的空间结构,设计了一种基于矢量水听器的高指向性二阶水听器,由六只三维矢量水听器和一只声压水听器组成,在平面波长中使用时六只三维矢量水听器可以简化至二维。利用等效电路法分析高指向性二阶水听器,推导了二阶水听器各通道的声压灵敏度表达式,并验证了公式的正确性。分析了二阶水听器测量原理与水听器工作频带的内在联系,并研究了矢量水听器失配对二阶水听器上、下限工作频率的影响,仿真分析了二阶水听器运用的近似测量原理和矢量水听器失配对二阶水听器指向性的影响。本文选用不同的敏感元件设计制作了三种矢量水听器,再由矢量水听器组合成三种二阶水听器,小型单轴向二阶水听器上限工作频率2kHz,中型单轴向二阶水听器上限工作频率2.5kHz,复杂结构三轴向二阶水听器上限工作频率1.6kHz。根据基础理论推导得到的声压灵敏度公式计算了二阶水听器各通道的理论声压灵敏度级,并给出了声压灵敏度级随频率的变化曲线。分别对设计的三种二阶水听器建模,利用有限元分析软件仿真分析二阶水听器在声场中的声散射,讨论了散射作用对二阶水听器附近声场声压和相位的影响,同时仿真分析了二阶水听器各通道的指向性和由声散射引起的矢量水听器的幅度和相位失配。本文对设计制作的三种矢量水听器样器的性能进行了测试,给出了指向性、灵敏度等测量结果,对组合而成的高指向性二阶水听器样器进行了测试,给出二阶水听器各通道的实测指向性图、灵敏度曲线等,测试结果与理论值能够较好的吻合,讨论了二阶水听器实测指向性与理论指向性差异的成因,验证了对二阶水听器指向性仿真分析的部分结论,并利用试验数据分析了矢量水听器幅度和相位失配,得到了与有限元仿真分析一致的现象,估计了二阶水听器的实际测量误差,证明了二阶水听器样器符合设计要求。
[Abstract]:Small and medium-sized underwater measuring platform is a common equipment for detecting and locating underwater targets. The array space of this kind of platform is small, and it is not suitable for installing large aperture array of underwater acoustic sensors. The application of single vector hydrophone in the platform has played a good role in improving the performance of the platform, but its beam angle is large, and this kind of blunt finger. It is difficult to obtain high azimuth resolution in the process of target localization, and it is more difficult to distinguish multiple targets which are close to each other. Therefore, it is still necessary to develop high directivity hydrophones with sharper directivity to improve the performance of the platform on small and medium-sized measuring platforms. High directivity second-order hydrophones are relay vector hydrophones. Then a new type of underwater acoustic sensor, compared with the vector hydrophone, the second-order hydrophone has a sharper quadrupole directivity. Its outstanding feature is that it has the ability to measure the second-order tensor in the acoustic field. Therefore, it is necessary to carry out the physical basic research and Engineering Research on the high-directivity second-order hydrophone. The basic theory of high directivity second-order hydrophone is studied firstly. The physical problems of underwater acoustic are discussed by using the concept of tensor, and the tensors measured by second-order hydrophone are studied by using the theory of pressure decomposition. The physical meaning of particle velocity and velocity gradient in fluid acoustic field is discussed. The velocity gradient tensor and the commonly used acoustic physical quantities are explained. Theoretical analysis proves that the non-uniformity of sound pressure at each point in the fluid microcluster in the sound field is the fundamental reason for the movement of the fluid microcluster. The particle velocity can describe the translation motion of the fluid microcluster, and the velocity gradient can describe the deformation and rotation of the fluid microcluster. The directivity performance of the second-order hydrophone is compared with that of the vector hydrophone. Theoretical analysis shows that the beam width of the quadrupole directivity of the second-order hydrophone is less than that of the dipole directivity of the vector hydrophone. The directivity of the second-order hydrophone is proved by comparing the beam width of the same combination of the two hydrophones. In this paper, the design theory of high directivity second-order hydrophone is studied. The measuring principle of second-order hydrophone is discussed. The spatial structure of second-order hydrophone is given. A high directivity second-order hydrophone based on vector hydrophone is designed. It consists of six three-dimensional vector hydrophones and one pressure hydrophone. Six three-dimensional vector hydrophones can be simplified to two-dimensional when used in planar wavelengths. The high directivity second-order hydrophones are analyzed by the equivalent circuit method. The pressure sensitivity expressions of each channel of the second-order hydrophones are derived and the correctness of the formulas is verified. The influence of vector hydrophone mismatch on the upper and lower limit operating frequency of the second-order hydrophone is studied. The approximate measuring principle of the second-order hydrophone and the influence of vector hydrophone mismatch on the directivity of the second-order hydrophone are simulated and analyzed. There are three kinds of second-order hydrophones: small uniaxial second-order hydrophone with upper limit operating frequency of 2 kHz, medium uniaxial second-order hydrophone with upper limit operating frequency of 2.5 kHz and complex structure third-axial second-order hydrophone with upper limit operating frequency of 1.6 kHz. Sensitivity level and the variation curve of pressure sensitivity level with frequency are given. Three kinds of second-order hydrophones are modeled. The acoustic scattering of the second-order hydrophone in the sound field is simulated and analyzed by finite element analysis software. The influence of scattering on the sound pressure and phase near the second-order hydrophone is discussed. At the same time, the second-order hydrophone is simulated and analyzed. The directivity of each channel and the amplitude and phase mismatch of the vector hydrophone caused by acoustic scattering are tested. The performance of three kinds of vector hydrophone prototypes designed and manufactured are tested. The directivity and sensitivity are given. The combined high directivity second-order hydrophone prototypes are tested and the second-order hydrophones are given. The measured directivity diagram and sensitivity curve of the channel are in good agreement with the theoretical values. The causes of the difference between the measured directivity and the theoretical directivity of the second-order hydrophone are discussed. Some conclusions of the simulation analysis of the directivity of the second-order hydrophone are verified. The amplitude and phase mismatch of the vector hydrophone are analyzed by the experimental data. The phenomena consistent with the finite element simulation analysis are obtained, and the actual measurement error of the second-order hydrophone is estimated. It is proved that the second-order hydrophone prototype meets the design requirements.
【学位授予单位】：哈尔滨工程大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TB565.1

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