水下运动目标辐射噪声源定位识别方法研究

Localization and identification of discrete noise sources distributed on underwater vehicle are often achieved through measurement of radiated noise from moving vehicle at small distance, and the result plays an important role in vibration and noise reduction of underwater vehicle. Conventional measurement methods cannot identify multiple discrete noise sources of moving vehicle, and also have low precision of localization. We propose a combination framework of localization and identification in joint domain of space and frequency, which uses high order acoustic sensor array to get spatial resolution, and Doppler analysis to get frequency resolution. The research will firstly focus on the Doppler invariant super directive beamforming of high order acoustic sensor array for low frequency radiated noise from moving underwater vehicle. Based on the beamforming output in spatial domain, the Doppler frequency analysis and scanning for moving sources will then carried out in frequency domain, and the nearest distance between moving vehicle and acoustic center of receiving array can be estimated, so that the distribution of discrete noise sources along the surface of underwater vehicle will be obtained at last. Experiments in water tank, lake and at sea will be carried out in this project. Discrete low frequency noise sources will be simulated using low frequency transducers such as UW350. The effects of source scale, measurement environment, and acoustic propagation at low frequency on the localization result will also be considered and studied to improve the performance of algorithms proposed in this project. Application studies to real underwater vehicle will also be carried out to lay a foundation for the practical advance of the principle and methods in this project.

通过近距离测量水下航行器运动时的辐射噪声并进而实现多个离散噪声源的准确定位，可为航行器减振降噪提供重要的参考。针对传统噪声测量分析方法精度较低、无法区分多个离散噪声源的问题，本项目提出通过采用高阶声场传感器阵列，结合多普勒分析，实现空域和频域联合的水下运动目标离散噪声源定位与识别。重点研究高阶传感器阵列接收水下航行器低频辐射噪声时的频域多普勒不变超指向性波束形成，并基于空域波束输出，在频域进行运动声源的多普勒扫描分析，估计出各个离散噪声源与测量接收点之间的最近通过时间，进而给出离散噪声源沿水下航行器表面的分布。开展水池和湖上、海上实验研究，采用低频声源模拟离散噪声源，分析噪声源分布尺度、测试环境、低频声传播等因素对噪声源定位与识别的影响，完善定位与识别方法，使本项目研究的原理、方法和技术在水下航行器离散噪声源定位中获得良好的应用效果。

通过近距离测量水下航行器运动时的辐射噪声并进而实现多个离散噪声源的准确定位，可为航行器减振降噪提供重要的参考。针对传统噪声测量分析方法精度低、无法区分多个离散噪声源的问题，本项目利用高增益传感器阵列，结合多普勒分析，实现空域和频域联合的水下运动目标离散噪声源定位与识别。主要研究成果包括：（1）研究了水下运动线谱噪声源定位和识别的测量模型，同时给出了由运动线谱噪声源形成的多普勒信号的瞬时频率曲线和瞬时频率变化率曲线的多项式相位信号模型建模方法。（2）针对水下低频低速运动的线谱噪声源瞬时频率曲线的特点，使用了差分多项式Chirplet变换方法计算正横时刻，并完成目标的运动参数估计。（3）针对同频噪声源因瞬时参数估计较为困难而导致定位精度受到影响的问题，提出了一种基于模基迭代处理的噪声源定位方法。（4）提出并使用了适合高阶多项式相位信号模型的瞬时频率变化率估计算法——L相位分布算法，从多普勒信号的瞬时频率变化率角度进行噪声源定位。（5）研究了圆环阵高增益波束形成方法以及研究并提出了在任意阵形下具有广义形式的高增益波束形成方法的闭式解。（6）从联合空时频三维信息从发，研究了波束域时频分析识别水下运动航行器低频线谱噪声源位置的方法。项目期间共发表学术论文38篇，其中被SCI索引论文7篇，申请发明专利3项。在运动目标瞬时多普勒频率提取方面做了丰富细致的研究工作，部分研究内容经过了消声水池实验和海上试验的验证，具有良好的应用效果。