水下声场高阶量理论分析及小孔径矢量线阵高阶梯度方位估计方法

The scalar information processing based on pressure hydrophone was promoted to vector information processing by using vector hydrophone which was researched and developed in the twenty-first century. It is possible that the information processing could be further promoted to dyadic information processing by using the particle velocity gradient hydrophone which was researched in recent years. Research of high order acoustic quantities render the new idea for solving the complicated problem of underwater acoustics. High order quantities of underwater acoustic analysis and application were researched in this project for complete the theoretical frame of underwater acoustic and improve the performance of underwater acoustic array. Firstly, the theory analysis method of high order quantities of underwater acoustic was built. The physical meaning of high order quantities of underwater acoustic was studied to complete the theoretical frame of underwater acoustic. Secondly, direction of arrival estimation using high order gradient based on small aperture vector hydrophone linear array and the method of high order hydrophone array processing were researched. The high order particle velocity gradient was obtained using the finite difference method to get the high order quantities of underwater acoustic was studied. Mode weighting direction of arrival estimation method using particle velocity high order gradient was proposed. The resolution of proposed target angle estimation method has additional capabilities such as frequency and steer direction independent, which broke through the performance decreasing limitation on linear array endfire direction and solved the problem of blunt directivity in low frequency. Small inter-sensor spacing results in very compact aperture. The 360 degree in horizontal plane and broad frequency direction of arrival estimation using small aperture vector hydrophone linear array was realized, which render the technique basis for improving the performance of sonar array.

二十一世纪发展完善的矢量水听器技术将声压水听器标量信息处理提升为质点振速的矢量信息处理，近年来出现的振速梯度水听器使水声信号处理进一步提升为张量信息处理成为可能，高阶声学量的研究为解决水声中的难题提供了新思路。本项目以完善水下声学分析理论体系和提高水下声纳性能为目标，研究水下声场高阶量理论分析及其应用。首先建立高阶声学量的理论分析方法，探究声场高阶量的物理含义，完善水下声场分析理论体系，然后研究基于小孔径矢量线阵的高阶梯度目标方位估计方法和高阶水听器阵列处理方法，探索声场高阶量的空间有限差分近似方法，提出质点振速高阶梯度模态加权目标方位估计方法。声场高阶量目标方位估计精度和目标入射方位及频率无关，突破了常规线阵端射方向性能下降的局限，解决了线阵低频指向性差的难题，大大减小了基阵孔径，实现了小孔径矢量线阵的全空间宽频带范围内的高精度目标方位估计，为提高声纳基阵的性能提供有力支持。

本项目对水下矢量声场高阶量理论分析及其应用问题进行了研究，开发了基于小孔径矢量线阵的高阶梯度目标方位估计方法和高阶水听器阵列的信号处理算法。进行了质点振速高阶量物理意义的分析。仿真研究了质点振速高阶量不同阶的指向性，并根据质点振速高阶量与常规量之间的关系研究了质点振速高阶量的获取方法。将质点振速高阶梯度在正交基底上进行模态分解，针对正交基底求取加权向量，将加权向量和质点振速高阶量进行运算，完成模态加权空域滤波，实现全空间和宽频段范围内的高精度目标方位估计析。仿真分析了不同条件下方位估计方法的性能。为了验证理论分析的正确性，开展了小孔径矢量线阵高阶梯度目标方位估计方法的试验研究，通过小孔径矢量线阵拾取空间多点的质点振速信息，利用空间有限差分获取质点振速高阶梯度量，实现质点振速高阶梯度目标方位估计。对试验数据进行了处理分析，并和理论结果进行对比，试验和理论结果基本相符。项目的研究成果为成功研制应用在岸基、浮标等有限空间或者小型便携式声纳中，具有十分广阔的应用前景。