Due to the dispersion of normal modes in shallow water, there exist regular striations on the interference spectrogram in space-frequency domain. Based on the range-frequency domain striations, waveguide invariant can be estimated with the prior knowledge of source range. Utilizing striations along the array, Rouseff and Zurk [J. Acoust. Soc. Amer. 130 (2011) EL76–EL81] proposed the striation-based beamforming (SBF), which shows a theoretical possibility to estimate waveguide invariant that is independent of source range. To make this beamforming technique more practical, its application requirements and performance limitation should be defined. These two issues are researched with the phase and amplitude relationships deduced by the frequency-shift compensation theory. It shows the source whose spectrum varies slowly and received signals that contain the complete information of transmission time are keys for applying SBF to real work. The azimuth limitation can lead to the degradation of array gain and distortion of interference structure. Matching parameters of waveguide invariant and source range, respectively, two modified striation-based beamformers are developed to eliminate the azimuth limitation. Simulation and experimental results are presented.

中文翻译：

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浅水水平线阵列基于条纹的波束形成和应用要求的性能指标

由于浅水中正模的色散，空频域的干涉谱图上存在规则的条纹。基于距离-频域条纹，可以利用源范围的先验知识估计波导不变量。利用阵列上的条纹，Rouseff 和 Zurk [J. 声学。社会党。阿米尔。 130(2011) EL76–EL81] 提出了基于条纹的波束形成 (SBF)，它显示了估计与源范围无关的波导不变量的理论可能性。为了使这种波束成形技术更加实用，应定义其应用要求和性能限制。用频移补偿理论推导出的相位和幅度关系对这两个问题进行了研究。它显示了频谱变化缓慢的源和包含完整传输时间信息的接收信号是SBF应用于实际工作的关键。方位角限制会导致阵列增益下降和干涉结构失真。分别匹配波导不变量和源范围的参数，开发了两种改进的基于条纹的波束形成器来消除方位角限制。给出了仿真和实验结果。