浅海环境中用于目标深度属性判别的线谱起伏特征量分析  

Analysis of line spectral fluctuation characteristics for source depth discrimination in shallow water

作　　者：邓玉鑫 刘雄厚[1,2] 杨益新 Deng Yu-Xin;Liu Xiong-Hou;Yang Yi-Xin(School of Marine Science and Technology,Northwestern Polytechnical University,Xi’an 710072,China;Shaanxi Key Laboratory of Underwater Information Technology,Xi’an 710072,China)

机构地区：[1]西北工业大学航海学院,西安710072 [2]陕西省水下信息技术重点实验室,西安710072

出　　处：《物理学报》2024年第13期175-189,共15页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:U2341203,12274346);国家重点研发计划(批准号:2016YFC1400200)资助的课题。

摘　　要：浅海环境中目标辐射线谱的起伏特征可用于水面、水下目标深度属性判别.已有研究未给出表征水面、水下线谱起伏差异的物理量性质,导致利用不同物理量进行目标深度属性判别时性能不佳.针对这一问题,本文从声源深度起伏所导致的线谱起伏出发,采用微分方法与统计方法对线谱起伏规律进行分析,研究了线谱起伏产生的物理机理,得到了适合用于水面、水下目标深度属性判别的物理量.首先,分别推导了复声压实部、声功率与声压幅值关于声源深度的导数关系式,得到了以上三种物理量在声源深度起伏时的起伏大小;其次,利用仿真实验数据从接收深度、声源水平距离、线谱频率等层面对理论推导进行验证,并对线谱的归一化起伏特征进行了分析.最后,利用海试数据验证了相关结论.结果表明,当声源的深度起伏时,水面、水下线谱的起伏差异源自各阶模态的相互作用.声源频率、声源水平距离、接收深度三种因素决定了模态间相互作用的性质.声压幅值适用于构建目标深度属性判别特征量,可用于表征低频线谱的强度起伏差异.数值仿真和海试数据处理结果表明,相较于声压实部和声功率,利用声压幅值构建的归一化水面、水下目标深度属性判别特征量具有更优性能.The difference in intensity fluctuation between a surface signal and a submerged signal can be used to discriminate the source depth in the shallow water waveguide.However,the properties of fluctuation distinction in intensity between surface source and submerge source are rarely studied,resulting in the poor performance of fluctuation-based methods sometimes.In this work,the intensity fluctuations caused by source depth fluctuations is analyzed by differential method and variance statistics method to figure out the physics of intensity fluctuations,and to present the suitable quantity for depth discrimination.Firstly,the derivative expression of real part,power and amplitude of the pressure field are respectively derived from the normal mode theory,hence their fluctuation quantities are specified.Then,the numerical examples,including the factor of receiver depth,source frequency and source range,are treated to verify the derivation and summarize the characteristic of fluctuations.The property of the intensity fluctuations is also compared with the distribution of normalized quantity on the depth dimension.Finally,the SWellEx-96 experimental data processing results validate the conclusions.The processing results of derivation,simulation data and experimental data show that the interactions between modes excited by the source give rise to the fluctuations.Meanwhile,the property of the interactions is affected by the received depth,source range and source frequency.Amplitude is capable of building a quantity based on fluctuations for source depth discrimination.For surface and submerged sources with lower frequency,their distinction in their fluctuations is stably represented by amplitude.In the SWellEx-96 experiment,the normalized values calculated from the amplitude of surface noise and submerged sound sources show the lowest difference of 0.5 and the highest difference of 2.5,indicating the effectiveness of using amplitude fluctuations to discriminate the sound source depth.

关 键 词：线谱起伏 深度属性判别 浅海环境 简正波 

分 类 号：P733.2[天文地球—物理海洋学] P714[天文地球—海洋科学]