海洋水声环境调查数据处理关键技术

发布时间：2018-10-21 17:32

【摘要】：海洋水声调查既是水声信道物理规律性研究的基础,又为声纳设备的设计和研制提供依据,一般包括声源级、声传播损失、噪声、海洋混响、声速剖面和海底声学特性测量等。海洋水声调查数据处理目标在于生成海洋声学调查数据处理结果数据库,为海洋环境信息系统建设提供基础性数据支持。海洋水声调查数据量大,传统的处理方法,人工干预度大,处理速度慢,对处理人员的专业性要求较高。本文重点研究声源级测量、声传播损失测量和噪声测量的数据自动处理关键技术,旨在提高处理效率,降低人员干预度和提高处理结果质量。本文从声纳方程入手,介绍了典型的水声调查方法和三分之一倍频程宽度水声参量的计算方法。利用球面扩展规律和水听器测量得到的信号级,推算声源级,利用声源级减去信号级得到声传播损失,利用周期图法估计噪声的功率谱。论文重点之一是研究实际海洋中的瞬态信号的自动检测方法。分析了海洋噪声的频谱特性,得出噪声的主要能量集中在100Hz以下的低频部分,采用Hinich方法和直方图法分析海洋噪声的高斯性,得出持续秒级的海洋噪声呈现非高斯分布,而噪声通过截止频率为100Hz的高通滤波器后,统计特性近似为高斯分布,因此检测前数据先通过高通滤波器滤波。将海洋噪声建模为海洋背景噪声和瞬态干扰的线性叠加,提出了基于模型的能量检测器的门限自适应设置方法,使得门限在近收发距离处高,随着距离的增加不断下降,这样兼顾了近接收距离处低虚警概率和远接收距离处高检测概率的要求。论文研究了实验环境中,水听器深度起伏对声传播测量的影响,仿真分析结果表明,该影响不能忽略。由此提出了基于模型的修正方法,即用模型预测某一收发距离和声源深度下,声传播损失随接收深度的变化规律,再利用多项式拟合固定深度附近声传播损失和接收深度的关系,进而将有深度扰动的测量值修正到固定深度处的值,通过实验数据,说明了方法的可行性。这是论文的又一重点。论文最后构建了海洋水声环境调查处理系统,包括声源级测量、声传播损失测量和噪声级测量等功能。处理系统首先对测量的原始数据作规范化整理,高通滤波,爆炸波或噪声截取,信息同步,生成预处理数据；然后对预处理数据进行1/3倍频程划分,计算相应的声源级、传播损失和噪声级参数。
[Abstract]:The underwater acoustic survey is not only the basis of the research on the physical regularity of underwater acoustic channel, but also provides the basis for the design and development of sonar equipment, generally including sound source level, loss of sound propagation, noise, marine reverberation, sound velocity profile and measurement of underwater acoustic characteristics, etc. The purpose of data processing of underwater acoustic survey is to generate the database of the data processing results of ocean acoustic survey, and to provide basic data support for the construction of marine environmental information system. Because of the large amount of data and the traditional methods of underwater acoustic survey, the degree of manual intervention is large, the processing speed is slow, and the professional requirement of the personnel is high. This paper focuses on the key techniques of sound source level measurement, sound propagation loss measurement and noise measurement data automatic processing, which aims to improve processing efficiency, reduce staff intervention and improve the quality of processing results. Based on sonar equation, this paper introduces the typical underwater acoustic survey method and the calculation method of 1/3 times width underwater acoustic parameters. By using the law of spherical expansion and the signal level measured by hydrophone, the sound source level is calculated, the sound propagation loss is obtained by subtracting the signal level from the sound source level, and the power spectrum of noise is estimated by using the period diagram method. One of the emphases of this paper is to study the automatic detection method of transient signals in the real ocean. The spectral characteristics of ocean noise are analyzed. It is concluded that the main energy of noise is concentrated in the low frequency part below 100Hz. The Gao Si character of ocean noise is analyzed by Hinich method and histogram method. After the noise passes through the high-pass filter with cut-off frequency of 100Hz, the statistical characteristic is approximately Gao Si distribution, so the data is filtered by high-pass filter before detection. The ocean noise is modeled as the linear superposition of the background noise and the transient interference, and the adaptive threshold setting method of the energy detector based on the model is proposed, which makes the threshold high at the close range and decreases with the increase of the distance. In this way, the requirements of low false alarm probability and high detection probability at near receiving distance are taken into account. The effect of hydrophone depth fluctuation on acoustic propagation measurement is studied in this paper. The simulation results show that the influence can not be ignored. Therefore, a model-based correction method is proposed, that is, the model is used to predict the variation of the sound propagation loss with the receiving depth at a certain transmitting distance and sound source depth. The relation between the sound propagation loss near the fixed depth and the receiving depth is fitted by polynomial, and then the measured value with depth disturbance is corrected to the value at the fixed depth. The feasibility of the method is illustrated by the experimental data. This is another important point of the paper. At the end of the paper, the system of underwater acoustic environment investigation and treatment is constructed, which includes sound source level measurement, sound propagation loss measurement and noise level measurement. The processing system first normalizes the measured raw data, high-pass filtering, explosive wave or noise interception, synchronization of information, generation of preprocessing data, and then divides the preprocessed data by 1 / 3 octave, and calculates the corresponding sound source level. Propagation loss and noise level parameters.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P733.2;TB56

【参考文献】