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浅海声场单模发射技术研究
文献类型：学位论文
| 作者 | 彭大勇 |
| 学位类别 | 博士 |
| 答辩日期 | 2009-05-26 |
| 授予单位 | 中国科学院声学研究所 |
| 授予地点 | 声学研究所 |
| 关键词 | 浅海声场 单模发射 闭环控制 最佳估计 |
| 其他题名 | Research on single-mode excitation in shallow water |
| 学位专业 | 信号与信息处理 |
| 中文摘要 | 单模发射即声场中单个简正波（即单模）声场的激发，通过布放在不同深度的多个换能器的同时发射来实现各号简正波之间的消长，使得声场中只存在单号简正波。单模具有辐射能量利用率高、传播损失低、避免多途干扰和抑制混响等优点，有广阔的应用前景。 单模发射分为开环发射和闭环发射两种。单模开环发射具有相当大的局限性。单模闭环发射属于新兴的研究课题，闭环控制算法无需发射阵到反馈阵之间的海洋环境先验知识，具有良好的自适应性。 本文首先研究了浅海单模发射的系统建模。将时变系统的可控制性、可观测性以及稳定性应用在单模发射系统。对声场的简正波形式的矩阵表达式以及声场格林函数矩阵进行了详细介绍。同时，研究了对声场可观测性有重要意义的简正波过滤技术，讨论了水听器阵的设计问题。 本文着重研究了单模发射的闭环控制问题，这也是本文的核心问题。本文详细推导了声场格林函数矩阵的各种估计方法，统一了各估计方法之间的关系。同时指出了现有方法存在的不足，并在此基础上通过研究格林函数矩阵的估计协方差，提出了一种最佳估计算法。设计了一种对格林函数矩阵作最佳估计的最佳发射阵权系数矩阵，基于此矩阵的单模发射算法可以使得单模激发过程以最快的速度收敛，并且发射稳定。算法的优势在模拟计算中得到了验证，并且给出了海上实验的结果。 本文最后通过仿真模拟讨论了影响单模发射的各种因素，结果可以作为对单模发射的一种参考。 |
| 英文摘要 | Single-mode excitation means to excite only a single mode in acoustic field. Single mode has a good application future for its properties such as high usage of energy, low transmit loss, avoiding multi-path disturbance and restricting reverberation. Single-mode excitation can be divided into open-loop and close-loop excitation. Open-loop excitation has some limitations. Close-loop excitation is a new technique. It firstly estimate Green’s function matrix according to the acoustic field received at vertical hydrophones feedback array. Using the estimated matrix, weight coefficient for each transducer can be obtained by an inverse operation to excite a given single mode. Close-loop excitation doesn’t need prior information about the ocean environment between the emission and the feedback array, so it’s well adaptive. In this thesis, single-mode excitation modeling is introduced firstly. Reachability, observability and stability of time-variant system are applied to singlemode excitation system. Matrix expression of acoustic field and Green’s function are introduced in detail. Meanwhile, mode filtering which is important for the observability of acoustic field is studied; the problem of hydrophone array design is discussed. Close-loop control of single-mode excitation is focused in this thesis. Methods to estimate Green’s function matrix are presented in detail and relations between these methods are stated. Meanwhile, in order to fix defect of former methods, an optimal source array weight matrix is presented to estimate Green’s function matrix by analyzing the estimation covariance of Green’s function matrix. Algorithm based on the weight matrix makes single-mode excitation converge at maximum speed and be steady. Advantages of the algorithm are confirmed by numerical simulations. Results of shallow water experiment are presented. Finally, factors that influence single-mode excitation are discussed by numeric simulation. Results of the simulations can be a reference to single-mode excitation. |
| 语种 | 中文 |
| 公开日期 | 2011-05-07 |
| 页码 | 91 |
| 源URL | [http://159.226.59.140/handle/311008/472]  |
| 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 | 彭大勇. 浅海声场单模发射技术研究[D]. 声学研究所. 中国科学院声学研究所. 2009. |
入库方式： OAI收割
来源：声学研究所
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