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题名	基于格林函数矩阵奇异值分解的海底参数反演
作者	雷晔灿
学位类别	博士
答辩日期	2008-05-30
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	单模发射 匹配场反演 模拟退火 格林函数
其他题名	Inversion of bottom parameters based on singular value decomposition transaction of Green function matrix
学位专业	信号与信息处理
中文摘要	单模技术，即浅海单个简正波声场激发技术，是以简正波理论为基础的，研究浅海声传播的有效方法。利用单模发射技术可以激发任意指定的单模和多模的声场，所以可以有针对性的选取具有某种特性的模式，比如衰减较小的低号模式， 来研究浅海声场，进行水下声通信和水下目标探测。 单模发射的最终目的，是寻找合适的发射阵加权系数，使得发射阵在该加权系数的控制下，可以激发出期望的单模声场。对于水平分层环境，不但反馈阵处接收到的是单模声场，而且反馈阵之外的任何地方均应是单模声场。但是实际的单模控制过程是，先根据环境参数预先计算出期望的单模声场，再用这个声场反馈控制发射阵的加权系数，使得加权系数逐步收敛至某个特定值，该特定值具有这样的特性：在该加权系数的控制下，发射阵激发的声场在反馈阵处是期望的单模声场。水文、海深可以通过测量得到较为准确的结果，而海底参数的估计则困难得多。海底参数的错误估计会导致这样的结果：反馈控制稳定后，在反馈阵处接收到的声场是期望的单模声场，但是在反馈阵之外的任何地方均不是单模声场，这显然不满足单模发射的要求。所以说海底参数和沉积层结构对单模发射有着至关重要的影响。 为了提高单模发射的质量，我们需要通过匹配场反演预先获知海底参数。结合单模发射的实现方式，本文提出了基于发射阵和接收阵之间的格林函数矩阵奇异值分解的海底参数反演方法，结合自适应下山模拟退火算法，采用Kraken声场计算程序，分别针对一层高声速海底模型，两层低声速和高声速沉积层海底模型，进行仿真反演计算，得到了海底环境参数。最后对2008年3月在海南三亚湾的海上试验数据进行了反演，对同一地点的多组发射数据，得出了一致的海底声速值，初步证明了反演方法的有效性。
英文摘要	Based on normal-mode theory, single normal-mode excitation technology is an effective method to study sound propagation problem in shallow water. An arbitrary designated mode or several modes of sound field can be stimulated by using single-mode excitation technology. In that way we can generate some mode with specific characteristic, for example, the low attenuation mode, in order to study the shallow water sound field, conduct underwater acoustic communication and detect underwater target. The excitation way of Single-mode theory is: firstly to calculate an ideal single-mode acoustic field according to environmental parameters, then use the feedback control algorithm to make weighting coefficients of source array gradually converge to particular value with such characteristics: source array can stimulate expected acoustic filed in the feedback array under the control of those weighting coefficients. Hydrologic parameters and the depth of the ocean can be measured accurately; however, it is much more difficult to estimate the seabed parameters. Inaccurate estimation of seabed parameters will lead to the result that after the feedback control we can receive expected single-mode acoustic field in the feedback array but could not obtain the perfect single-mode filed in other place around the feedback array. That obviously does not meet the requirements of single-mode excitation. Therefore seabed parameters and sediment structure have a great impact on single-mode excitation. In order to improve the quality of single-mode excitation, we need to conduct geoacoustic inversion using matched-filed processing technology. According to the control way of single-mode excitation, a new objective function is presented in this paper. In the process of excitation, Green’s function between the source array and feedback array would be obtained. Synthetic acoustic field data and modeled (replica) filed data each has its own Green’s function. Make the singular value decomposition transaction to both of the Green’s function matrixes. Then their singular value margin is regarded as the objective function. Adopting the adaptive simplex simulated annealing (ASSA) search algorithm and Kraken sound field calculation program, this inversion method is applied to test cases such as one layer with high bottom velocity model and two layers (including sediment layer) with both high and low bottom velocity models. Finally, we carry out the geoacoustic inversion to the data obtained in maritime experimentation in March 2008 in Sanya Bay. For multiple excitation data in the same place, the results reach a consensus bottom velocity value. That verifies the effectiveness of this inversion method.
语种	中文
公开日期	2011-05-07
页码	71
内容类型	学位论文
源URL	[http://159.226.59.140/handle/311008/418]
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	雷晔灿. 基于格林函数矩阵奇异值分解的海底参数反演[D]. 声学研究所. 中国科学院声学研究所. 2008.

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