宽带信号波束形成算法研究

发布时间：2018-06-22 15:27

本文选题：宽带波束形成 + 聚焦变换　；参考：《西北工业大学》2015年博士论文

【摘要】：在水声信号处理领域中宽带信号波束形成是其主要的研究方向之一,对宽带水声信号的处理远比窄带信号困难很多。本文研究了通过聚焦变换实现宽带信号的波束形成算法,并通过仿真和实验对算法进行验证。具体的研究内容包括:1、研究了经典的窄带信号的波束形成算法,给出了常用基阵的理想阵列流形和实测阵列流形的计算方法,描述了用于验证本文算法的实测阵列流形的获取方法和步骤。2、研究了决定宽带聚焦波束形成算法效果的两个因素。一个是聚焦矩阵,一个是聚焦频率。给出了最佳聚焦矩阵和最佳聚焦频率的确定方法,并根据最佳聚焦矩阵的不同求解方法给出了不同的聚焦算法。文中首次对最佳聚焦频率的有效性进行了仿真分析和水池实验的验证。仿真分析和水池实验表明:在最佳聚焦频率处实现的宽带聚焦波束形成具有更好的效果。3、提出基于最佳聚焦频率的二阶锥宽带聚焦波束形成算法。首先对二阶锥规划方法以及二阶锥规划的求解软件SeDuMi进行了介绍,描述了将优化问题转化为二阶锥规划求解形式的过程。然后介绍了基于二阶锥规划的常用波束形成算法,在基于二阶锥的宽带聚焦波束形成算法中,引入了最佳聚焦频率的确定方法,提出基于最佳聚焦频率的二阶锥宽带聚焦波束形成算法,并通过仿真实验以及水池实验验证了该算法的有效性。仿真分析和水池实验表明:本文提出的基于最佳聚焦频率的二阶锥宽带聚焦波束形成算法充分利用了最佳聚焦频率的有效性,又结合了二阶锥的窄带波束形成算法,使宽带聚焦波束图主瓣更窄,旁瓣级更低。4、与RCB(Robust Capon Beamforming)算法相结合,提出了一种优化的宽带聚焦波束形成算法。首先介绍了椭球体的基本理论,在椭球体的不确定约束条件的基础上,从协方差估计的角度介绍了RCB算法的原理,并对RCB算法进行了详细的求解,最后给出了RCB算法的具体求解步骤,在仿真实验中通过与MVDR(Minimum Variance Distortionless Response)算法在窄带波束形成中的对比,体现了RCB算法的优越性。由于通过RCB算法可以得到更接近真实的导向矢量,因此可以将其与宽带聚焦波束形成算法相结合,用来修正聚焦变换预处理的聚焦矩阵。本文充分考虑了最佳聚焦频率的确定问题,与RCB算法相结合,提出了一种优化的宽带聚焦波束形成算法。仿真实验以及水池实验表明宽带信号通过RCB算法校正的最佳聚焦矩阵聚焦到最佳聚焦频率上可以得到更窄的主瓣,使束宽保持较好的恒定,并且旁瓣级也更低。5、提出了一种双重优化的宽带聚焦波束形成算法。首先,利用RCB算法修正聚焦矩阵,然后使由宽带信号划分的各个窄带信号通过修正后的聚焦矩阵聚焦在确定的最佳聚焦频率上,最后再对窄带数据利用二阶锥方法实现波束形成。仿真实验、水池实验以及湖试实验表明双重优化的宽带聚焦波束形成算法充分利用了RCB算法,最佳聚焦频率,二阶锥波束形成算法的优点,综合作用于宽带波束,使得实现的宽带聚焦波束形成在本论文中具有最优的波束形成效果。
[Abstract]:Wideband signal beamforming is one of the main research directions in the field of underwater acoustic signal processing. The processing of wideband acoustic signal is much more difficult than that of narrow band signal. This paper studies the beam forming algorithm of wideband signal through focusing transformation, and validates the algorithm through simulation and experiment. The specific research contents include: 1, The classical beamforming algorithm of narrow band signal is studied. The calculation method of the ideal array manifold and the measured array manifold of the common base array is given. The method and step of obtaining the measured array manifold used to verify this algorithm.2 are described. Two factors determining the effect of the wide-band focusing beamforming method are studied. One is the focusing moment. One is the focusing frequency. The optimal focusing matrix and the optimal focusing frequency are given, and different focusing algorithms are given according to the different solution methods of the best focusing matrix. The validity of the optimal focusing frequency is first simulated and verified by the pool experiment. The broadband focused beam formed at the best focusing frequency has a better effect.3. The two order cone broadband focusing beamforming algorithm based on the best focusing frequency is proposed. First, the two order cone programming and the solution software SeDuMi of the two order cone programming are introduced, and the optimization problem is transformed into a two order cone programming solution. Then the common beamforming algorithm based on the two order cone programming is introduced. In the wide-band focusing beam forming algorithm based on the two order cone, the optimal focusing frequency is introduced and the two order conical wideband focusing beam forming algorithm based on the optimal focusing frequency is proposed. The algorithm is verified by simulation experiments and pool experiments. Simulation analysis and pool experiments show that the two order conical wideband focusing beamforming algorithm based on the best focusing frequency makes full use of the effectiveness of the best focusing frequency, and combines the narrowband beam forming algorithm of the two order cone, which makes the main lobe of the wideband focused beampattern narrower, the side lobe lower.4, and RCB (Robust Capo). N Beamforming) combined with the algorithm, an optimized wideband focusing beam forming algorithm is proposed. First, the basic theory of ellipsoid is introduced. Based on the uncertainty of the ellipsoid, the principle of the RCB algorithm is introduced from the angle of covariance estimation, and the RCB algorithm is solved in detail. Finally, the RCB algorithm is given. In the simulation experiment, the comparison of the MVDR (Minimum Variance Distortionless Response) algorithm in the narrowband beam formation shows the superiority of the RCB algorithm. Because the RCB algorithm can get closer to the true guidance vector, it can be combined with the wide-band focusing beam forming algorithm for correction. Focusing on the focused transformation preprocessed focus matrix. In this paper, the optimal focusing frequency is fully considered. An optimized wideband focusing beam forming algorithm is proposed by combining with the RCB algorithm. The simulation experiment and the pool experiment show that the best focus matrix corrected by the RCB algorithm can be obtained on the optimal focusing frequency. To a narrower main lobe, the width of the beam is kept constant and the sidelobe level is lower.5. A dual optimized wideband focusing beam forming algorithm is proposed. First, the focus matrix is corrected by the RCB algorithm, and the narrowband signals divided by the broadband signal are focused on the optimal focusing frequency by the corrected focusing matrix. Finally, the two order cone method is used to realize the beamforming. The simulation experiment, the pool experiment and the lake test experiment show that the dual optimized wideband focusing beam forming algorithm fully utilizes the advantages of the RCB algorithm, the best focusing frequency and the two order cone beamforming algorithm. Beam forming has the best beamforming effect in this paper.
【学位授予单位】：西北工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U666.7

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