低频小尺度声矢量阵平台散射效应修正研究

Finite size acoustic vector sensor array can obtain more sound field information at quasi-single spatial point, breaking through the limitation of array aperture on low-frequency detection performance of array, and has great application prospects in underwater remote target detection and information network construction. However, in practice, the scattering effect of the array working platform will lead to the distortion of the surrounding sound field, which seriously affects the verification and promotion of the Finite size array theory. Focusing on the calibration of platform scattering effect, this project uses the research methods of theoretical analysis, modeling simulation and experimental verification to analyze the low frequency near-field scattering effect of complex platform structure. By studying the distortion law of signal field and background noise field caused by near-field scattering, the physical sound field is excavated, and the signal field model based on common characteristics is established, and the signal field model is proposed and dispersed. The robust adaptive correction method for matching the radiation field model solves the problems of the existing low-frequency near-field scattering research, the poor applicability of scattering research results, and the limitation of signal processing performance of small-scale array caused by the lack of physical model. The feasibility and applicability of the research results are verified by field experiments, and the design theory of small-scale vector sonar system is improved, so as to make the underwater low-frequency long-range target reliable.

小尺度声矢量阵可以在准单空间点处获取更多声场信息，突破了基阵孔径对基阵低频探测性能的限制，在水下远程警戒探测与信息网构建方面具有巨大应用前景。但实际中，基阵工作平台的散射效应会导致周围声场畸变，严重影响小尺度基阵理论的验证与推广。本项目围绕平台散射效应修正需求，采用理论分析、建模仿真和实验验证相结合的研究方法，对复杂平台结构体的低频近场散射效应进行分析，通过研究近场散射引起的信号场和背景噪声场畸变规律，挖掘其物理场规律，建立基于共性表征的接收场模型，提出与散射场模型相匹配的稳健声散射修正方法，解决现有低频近场散射研究少、散射研究结果适用性差、物理模型缺失导致小尺度阵信号处理性能受限等问题，并通过外场实验验证研究成果的可行性与适用性，完善小尺度矢量声呐系统设计理论，加快小尺度声矢量阵从理论研究向工程应用的研究进程。

小尺度声矢量阵可以在准单空间点处获取更多声场信息，突破了基阵孔径对基阵低频探测性能的限制，在水下远程警戒探测与信息网构建方面具有巨大应用前景。但实际中，基阵工作平台的散射效应会导致周围声场畸变，严重影响小尺度基阵理论的验证与推广。本项目围绕平台散射效应修正需求，对复杂平台结构体的低频近场散射效应进行了分析，通过对近场散射引起的信号场和背景噪声场畸变共性特征的挖掘，提出与散射场模型相匹配的波束形成方法，主要创新性贡献为针对深远海探测应用前景，提出利用小尺度矢量体积阵的空间差分提取各阶多极子模态，并通过多极子模态与球谐波函数之间的关系组成三维波束，算法与球面声压阵相比有更好的稳健性；在此基础上，为进一步优化阵列结构，又通过垂直振速信息的合理利用，提出了一种可用平面阵列结构得到全空间指向性的三维波束形成方法，所提方法在低频段能够获得相同阵增益的同时有着更好的稳健性；最后，针对有界水域的外场校准问题，提出了基于多个辅助源的修正方法，并在青岛近海进行了算法验证，本项目所用小尺度阵孔径不大于1m，在71Hz频点处海上实测增益8.5dB，远优于相同参数下的传统阵列。通过本项目的研究，建立了小尺度矢量阵平台低频近场声散射修正理论，形成了基于声场特性的小尺度矢量阵被动探测技术储备，为突破现有低频近场散射研究少、散射研究结果适用性差、物理模型缺失导致小尺度阵信号处理性能受限等问题提供了重要手段，完善了小尺度矢量声呐系统设计理论，为水下低频远程目标可靠探测提供了新思路。