QQ客服 官方微博 反馈留言

题名	浅海混响中简正波反向散射矩阵的准可分离性及其反演方法
作者	吴金荣
学位类别	博士
答辩日期	2005
授予单位	中国科学院声学研究所
授予地点	中国科学院声学研究所
关键词	反向散射矩阵 可分离性 反演
其他题名	Quasi-separability and Inversion Methods of Modal Back-scattering Matrix in Shallow water Reverberation Model
中文摘要	浅海混响是浅海主动声纳系统的主要干扰之一，同时也包含了大量的海洋环境信息。从混响数据中提取海底参数、水文参数等海洋环境参数是极有挑战性、而且很有意义的课题。本文介绍从混响数据中提取海底反向散射矩阵的情况，并且研究海底反向散射矩阵的性质。根据描述海底散射情况的函数可以将浅海混响模型分成两类，一类是经验散射函数混响模型，另一类是波动散射混响模型。本文将采用一种常见的波动散射混响模型，Born近似混响模型，来进行进一步的工作。在这Born近似混响理论基础之上，给出反向散射矩阵的定义，并且给出粗糙界面反向散射矩阵和海底介质体积不均匀性反向散射矩阵的具体表达式。海底反向散射矩阵是描述混响过程中入射简正波与散射简正波之间祸合关系的重要参量。本文从矩阵的可分离性近似，模空间特性两个不同角度，对海底反向散射矩阵进行理论与数值分析。研究结果表明：粗糙界面海底反向散射矩阵是准可分离的，而海底介质体积不均匀性反向散射矩阵是不可分离的；在模空间，随着距离的增大，有效反向散射矩阵中与高阶简正波对应的矩阵元素对混响的相对贡献越来越小。曾经有一些工作试图从混响数据里反演出海底反向散射矩阵，而且这些反演工作往往是建立在经验公式（如Lambert散射定律）或假设反向散射矩阵是可分离的基础之上的。但是有很多情况海底反向散射矩阵和Lambert散射定律并不符合，反向散射矩阵也不是可分离的。本文在两种可分离海底反向散射矩阵反演方法的基础之上，给出了两种没有任何海底散射先验知识的情况下，利用混响数据反演出浅海海底反向散射矩阵的不可分离反演方法，并且进行了数值计算。同时讨论了噪声对海底反向散射矩阵反演的影响。最后利用南海混响实验数据对本文提出的海底反向散射矩阵反演方法进行验证。首先对混响数据进行简正波过滤，然后利用可分离反演与不可分离反演方法分别对海底反向散射矩阵进行反演。结果发现利用混响数据可以很好地反演出可分离的反向散射矩阵与不可分离的反向散射矩阵，其中可分离的反向散射矩阵的反演则相对容易。
英文摘要	Shallow water reverberation is one of the fiercest interference to the sonar, and it contains a lot of information of the ocean environment. Extracting bottom parameters, sound profile and etc. is a challenging topic for a long time. In this paper, the case of extracting the bottom back-scattering information from reverberation data was presented. And the characteristics of the back-scattering were given. Shallow water reverberation models can be divided into two kinds according to bottom scattering function. One kind is empirical scattering law reverberation model, the other one is full wave reverberation model. In this paper, one of full wave reverberation models would be used, which is Born approximation reverberation theory. The definition of back-scattering matrix and its detailed description were also given. Bottom back-scattering matrix of normal reverberation model describes the coupling relationship between incident normal mode and scattering normal mode in the shallow water. The theory and numerical analysis of back-scattering matrix was given in two aspects: 1) Separable approximation, and 2) Mode-space. The analysis results show that: the roughness bottom back-scattering matrix is quasi-separable; in mode-space, the relative contribution of matrix element of higher modes to shallow water reverberation intensity decreases with the increasing of horizontal range. There are some work dealing with the extraction of back-scattering matrix from the reverberation data. However, the inversion are based on either empirical law (Lambert' law) or an assumption that back-scattering matrix is separable. Furthermore, there are many cases where there is marked departure from the Lambert's law, and the assumption of the separability of back-scattering matrix. Here, two kinds of separable inversion methods of back-scattering matrix were given. And then two kinds of unseparable inversion methods of back-scattering matrix were also presented. Numerical simulation of back-scattering matrix inversion was conducted and the effect of noise to back-scattering matrix inversion was discussed. At last, reverberation data processing was given as the validity of the inversion methods proposed in this paper. Firstly, normal mode filtering of reverberation data was conducted. Secondly, the two inversion methods were carried out. Thirdly, the inversion result was presented. The two kinds of back-scattering matrix were inversed for reverberation data successfully, and the separable inversion of back-scattering matrix was relatively easier.
语种	中文
公开日期	2011-05-07
页码	76
内容类型	学位论文
源URL	[http://159.226.59.140/handle/311008/1042]
专题	声学研究所_声学所博硕士学位论文_1981-2009博硕士学位论文
推荐引用方式 GB/T 7714	吴金荣. 浅海混响中简正波反向散射矩阵的准可分离性及其反演方法[D]. 中国科学院声学研究所. 中国科学院声学研究所. 2005.

个性服务

查看访问统计

相关权益政策

暂无数据

收藏/分享

除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。