【作者】 李超；

【导师】 刘志红； 范强；

【作者基本信息】 青岛理工大学 ， 机械（专业学位）， 2023， 硕士

【摘要】 信号波达方向(Direction of Arrival,DOA)估计在雷达、声呐、语音处理以及无线通信等领域得到了广泛应用。随着声源类型、声环境复杂度及应用场景多样性等实际需求的出现,对测向系统的DOA估计精度、估计维度及分辨力要求越来越高。其中,稀疏重构类DOA估计算法因其在具有超高角度分辨率的同时,能较好地适应以小快拍、低信噪比与相干性为特点的现代测向系统,而成为热点研究课题之一。实际情形中,声源多为具有明显块稀疏性和空间连续角度分布特点的扩展声源,但相关DOA估计成果较少并基本局限于一维。此外,现有点源算法也因扩展声源会使得麦克风测量矩阵相关性强和观测信号呈现阶段线性特征而失配。由此,为更精确地描述目标空间特性,本文基于稀疏重构类算法原理,提出了一种全变分正则化的二维DOA估计方法(Two-dimensional DOA Estimation Based on Total Variational Regularization for Spatially Coherent Extended Sound Sources,2DTV-CES)。本文研究得到国家自然科学基金项目(61871447)资助。主要工作内容概括如下:(1)明确阵列信号DOA估计基本原理的基础上,研究了稀疏重构类算法原理与相关信号的接收模型;分析了已提出的多种经典子空间类算法与正则化类算法的原理及其优缺点。(2)针对空间扩展声源,研究分析了其相关性与块稀疏性特征机理,明确其表现形式并构建了扩展声源模型。(3)针对传统稀疏DOA估计方法在估计扩展声源时的性能下降问题,提出了一种全变分正则化二维稀疏测向方法。在构建满足相应约束条件的二维阵列流形矩阵及其过完备表述以实现声源稀疏表示的基础上,构造了变分结构矩阵,由全变分模型的系数连续差异约束特性,促进解的分段常数轮廓的形成,并结合稀疏约束项,实现了扩展声源的二维DOA估计。(4)2DTV-CES方法的数值仿真研究。以多种扩展声源为识别对象,所得数值仿真结果验证了所提方法的空间角度估计能力以及普适性;与其他经典方法在不同信噪比、稀疏度条件下进行比较分析,所得数值仿真结果验证了所提方法的鲁棒性与优异性。(5)2DTV-CES方法的实验研究。分别于理想半消声室环境与复杂外场环境中,对多种实际扩展声源信息进行采集,数据在预处理后,由所提方法进行DOA估计所得结果,与数值仿真部分相互印证,进一步验证了方法的实际适用性。更多还原

【Abstract】 Direction of Arrival(DOA)estimation has been widely used in radar,sonar,speech processing and wireless communication.With the emergence of practical requirements such as sound source type,acoustic environment complexity and application scene diversity,the requirements for DOA estimation accuracy,estimation dimension and resolution of direction finding system are getting higher and higher.Among them,the sparse reconstruction DOA estimation algorithm has become one of the hot research topics because it can better adapt to the modern direction finding system characterized by small snapshots,low signal-to-noise ratio and coherence while having ultra-high angle resolution.In practice,most of the sound sources are extended sound sources with obvious block sparsity and spatial continuous angle distribution characteristics,but the related DOA estimation results are less and basically limited to one dimension.In addition,the existing point source algorithm is also mismatched due to the strong correlation of the microphone measurement matrix and the stage linear characteristics of the observation signal due to the extended sound source.Therefore,in order to describe the spatial characteristics of the target more accurately,based on the principle of sparse reconstruction algorithms,this paper proposes a two-dimensional DOA estimation method based on total variation regularization(2DTV-CES).The main work is summarized as follows:(1)Based on the basic principle of DOA estimation of array signals,the principle of sparse reconstruction algorithm and the receiving model of related signals are studied.The principles,advantages and disadvantages of various classical subspace algorithms and regularization algorithms are analyzed.(2)For the spatial extended sound source,the mechanism of its correlation and block sparsity is studied and analyzed,and its expression form is defined and the extended sound source model is constructed.(3)Aiming at the performance degradation of traditional sparse DOA estimation methods in estimating extended sound sources,a two-dimensional sparse DOA estimation method based on total variation regularization is proposed.On the basis of constructing a two-dimensional array manifold matrix satisfying the corresponding constraints and its over-complete representation to realize the sparse representation of the sound source,a variational structure matrix is constructed.The continuous difference constraint of the coefficients of the total variational model promotes the formation of the piecewise constant contour of the solution.Combined with the sparse constraint term,the two-dimensional DOA estimation of the extended sound source is realized.(4)Numerical simulation of 2DTV-CES method.Taking a variety of extended sound sources as recognition objects,the numerical simulation results verify the spatial angle estimation ability and universality of the proposed method.Compared with other classical methods under different SNR and sparsity conditions,the numerical simulation results verify the robustness and superiority of the proposed method.(5)Experimental study of 2DTV-CES method.In the ideal semi-anechoic chamber environment and the complex external field environment,a variety of actual extended sound source information is collected.After the data is preprocessed,the DOA estimation results obtained by the proposed method are mutually confirmed with the numerical simulation part,which further verifies the practical applicability of the method.更多还原