利用距离–频率干涉结构提高深海影区声场的水平纵向相关
Improving the horizontal-longitudinal correlation of acoustic field in the shadow zone in deep water using range-frequency interference structures
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摘要: 深海影区声场的水平纵向相关性迅速减弱, 导致水平阵列在此区域的探测性能受到极大限制。为此, 基于距离–频率干涉结构对深海影区中不同纵向间隔的声场进行频移补偿, 以提高影区声场的水平纵向相关性。首先基于某次深海实验的水文环境, 对深海影区内的距离–频率干涉结构和水平纵向相关进行了仿真分析, 采用等效波导不变量对水平阵列不同纵向间隔处的接收声场进行频移补偿, 提高了影区声场的水平纵向相关性。然后分析了深海实验中第一影区3个深度和2个距离处接收声场的水平纵向相关性。数据处理结果显示, 频移补偿后的声场水平纵向相关长度较频移补偿前提高大约4~11倍。以上结果表明, 利用距离–频率干涉结构对深海影区内的水声阵列接收声场进行频移补偿, 可有效提高影区声场的水平纵向相关性。Abstract: The horizontal-longitudinal correlation of the sound field decreases rapidly in the shadow zone of the deep sea, which severely limits the detection performance of the horizontal array in this area. This paper employs a range-frequency interference structure to frequency-shift compensate the acoustic field at different longitudinal intervals to improve the horizontal-longitudinal correlation of the acoustic field in the shadow zone. Firstly, the range-frequency interference structure and the horizontal-longitudinal correlation are analyzed by simulation based on a deep-sea experimental environment, and the simulated horizontal-longitudinal correlation of the acoustic field is improved through frequency-shift compensation by using an equivalent waveguide invariant. Then the experimental acoustic data from the deep-sea experiment is analyzed. The horizontal-longitudinal correlation of the received acoustic field in the first shadow zone at three depths and two ranges is processed. The data processing results show that the horizontal-longitudinal correlation length after frequency-shift compensation is increased by approximately 4 to 11 times compared to before the frequency-shift compensation. The simulated and experimental results demonstrate that the use of a range-frequency interference structure for frequency-shift compensation of the received acoustic field can effectively improve the horizontal-longitudinal correlation of the sound field in the shadow zone of the deep sea.