浅海中水平阵时反聚焦性能研究

Research on the retrofocusing performance of horizontal time-reversing arrays in shallow water

在浅海波导中,垂直时反阵可以跨越整个波导,能对大多数简正波模态进行精确采样。相比垂直阵,水平阵因便于安装在舰艇或永久布在海底放而更具有实际意义。本文在给定声源及海洋环境信息的条件下,通过仿真计算在声源处取得了较好的聚焦效果。对比垂直阵,计算了同种环境下水平阵取得较好时反聚焦效果所需孔径的大小,并分析了水平时反阵孔径一定,基元数减小;发射信号频宽的变化对时反聚焦性能造成的影响。得出大孔径的水平时反阵具有较好的时反聚焦性能,窄带信号较单频信号能改善水平阵时反聚焦性能的结论。最后处理了2002年海试数据,根据反演出的海底参数选择其中两组信号数据做时反处理,水平距离的定位误差为1.9%和2.2%。

Vertical linear array can span the whole wave-guide and can sample most normal modes accurately in the shallow water wave-guide. Horizontal linear array has more applied significance than vertical linear array because it is more convenient to be installed on the naval ships or fixed on the bottom of sea. From this paper, obvious focus effects can be seen in the place of sound source through the simulation with the given sound source and environment of the sea. Compared to vertical linear array, the length of the horizontal linear array needed is given to gain effective retrofocusing. Then the paper analyses how retrofocusing effect changes with the sensor aperture, the ratio of distance between sensors and the width of source wave frequency band. Finally it concludes that the horizontal linear array with huge aperture can obtain good time-reversal retrofocusing effect, and also the narrowband signal can be used to improve the performance of the retrofocusing. At last, two singals have been chosen from the data of experiment on the sea in 2002, and the error of the level range location is 1.9% and. 2.2%.