等声速环境中目标前向声散射简正波耦合的垂直阵空域响应特征

水下目标的前向声散射会引起声波传播过程中的简正波耦合效应,使得接收声场结构发生变化,研究目标前向散射引起的垂直阵列上空域响应变化特征,可实现对直达波强干扰背景下的前向散射检测。通过将垂直阵波束形成技术分别用于信道中目标散射场理论模型计算数据和湖上实验验证数据,分析了等声速环境中目标前向声散射简正波耦合的垂直阵空域响应特征。结果表明,目标靠近接收端时前向散射引起的声波垂直达到结构与无目标时相比差异显著,高阶简正波向低阶简正波转化导致信号到达时延宽度展宽,采用指向水平方向的窄波束可显著提取目标前向散射引起的接收声波变化特征。 

Modal coupling response on vertical hydrophone array caused by forward scattering from intruder in the isovelocity underwater environment

When target is submerged into underwater acoustic waveguide, the modal coupling effects will be caused, thus leading to wavefield structure aberration. Investigation on the modal coupling response on vertical hydrophone array is benefit for detection of forward scattering under strong direct blast. The beamforming technology on vertical array is executed on the data from the forward scattering model and experiment respectively. The modal coupling response on the vertical hydrophone array caused by forward scattering from intruder is studied. The results show that the response aberration is significant when the intruder is close to receivers, and the arrivals will be expanded by the transformation from high order modes to low order modes. The field aberration could be acquired significantly with a narrow horizontal beam.