源致内波引起的声场扰动及其检测方法  

Acoustic field fluctuation caused by source-generated internal waves and its detection method

作　　者：何兆阳 雷波[1,2] 杨益新 He Zhao-Yang;Lei Bo;Yang Yi-Xin(School of Marine Science and Technology,Northwestern Polytechnical University,Xi’an 710072,China;Qingdao Research Institute,Northwestern Polytechnical University,Qingdao 266200,China)

机构地区：[1]西北工业大学航海学院,西安710072 [2]西北工业大学青岛研究院,青岛266200

出　　处：《物理学报》2023年第14期137-151,共15页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12174311);陕西省自然科学基础研究计划(批准号:2023-JC-JQ-07)资助的课题。

摘　　要：水下目标体在密度分层流体中航行时会激发内波,这种内波常被称为源致内波,具有难以消除的特性.本文对声波穿过运动球体激发内波后产生的起伏进行研究,结果表明源致内波对声场的影响范围远大于目标体,声场变化的强度与覆盖范围均与目标穿越角度呈反比.进一步提出了一种基于滑动窗主分量分析的处理方法,通过短时窗信号子空间重构对声场微弱起伏进行增强处理,并用湖上实验证明了所提方法具有稳健性.研究结果表明,基于源致内波声起伏的探测方法可以对目标进行探测,具有覆盖范围广、稳健性高的优点.The development of noise reduction and silencing technology has brought great difficulties to underwater target detection,and more target characteristics need further studying.When a submerged target travels through density-stratified environment,the fluid will oscillate behind the target owing to gravity and buoyancy and generate internal waves,which are often referred to as source-generated internal waves.These internal waves are difficult to eliminate,which can cause the sound speed profiles to fluctuate.Therefore,these internal waves are expected to be effective for detecting underwater target.In this paper,the fluctuations of the received sound passing through the internal waves produced by a moving sphere are investigated.A typical shallow stratified environment is set up,and internal wave fields generated by a sphere moving in many horizontal directions are simulated.According to the simulation results,these internal wave fields have a much wider range than the scenario of the target body.Based on the relationship between the amplitude of the internal wave and the variation of sound speed,range–dependent sound speed profiles are constructed,and model based on ray acoustics is used to analyze the aberration strength of passing sound fields.Results show that the strength aberration is inversely proportional to the target passing angle,and these characteristics can be covered by the background.Focusing on this problem,an extraction method based on principal component analysis with sliding window is then proposed.The uncorrelation between the disturbance of internal wave and background signal is utilized,and interference is suppressed by removing the component in No.1 principal component space,and retaining the No.2–No.k subspace.Detection can be executed based on multi period received data from single hydrophone.A lake experiment is conducted to verify the performance.A detection scenario of single source and single receiver is established,and the AUV target crosses source–receiver line multiple times.T

关 键 词：源致内波 声场强度变化特征 滑动窗主分量分析 目标探测 

分 类 号：TB566[交通运输工程—水声工程]