频率自适应最优权重阵列干涉条纹处理技术

考虑长基线水平阵列波束形成对声场模态呈现的滤波特征,建立了一种随频率改变滤波通带的阵列权矢量设计方法。基于简正波理论,结合声场波束形成特点,在分析了常规波束形成信号LOFAR谱图干涉条纹的清晰度和条纹结构不同于单水听器输出信号条纹现象基础上,采用线性等式约束的二次优化模型,给出了一种频率自适应的最优权重估计。数值仿真验证和试验数据分析表明,利用该方法设计的最优权重阵列波束处理,可以滤波出SRBR(Surface-Reflected Bottom-Reflected)或N-SRBR(Non-Surface-Reflected Bottom-Reflected)模态组成的波束形成信号,信号谱图干涉条纹斜率与理论分析基本一致。 

A frequency adaptive optimal array weighted method of interference striations

Considering the filter properties of the long horizontal line array (HLA) to the sound field modes, we established an adaptive optimal method to design HLA weights, which can change the filter pass band with the frequency. Using the normal modes theory and combining with the feature of the sound field HLA beam forming, and analyzing the differences of definition and slope in the LOFAR (Low Frequency Analysis Recording) spectrogram between the single- hydrophone and the beam former, a frequency adaptive optimal estimate was obtained by solving a quadratic optimization model with linear equality constraint. The numerical simulation and the experimental data analysis indicated that we can obtain the beam former signal with the designed optimal array weight which was made up by the Surface- Reflected Bottom-Reflected modes or Non-Surface-Reflected Bottom-Reflected modes. The slope of striations in the signal spectrogram fitted well with the theoretical analysis.