矢量水听器宽带多途信号仿真及俯仰角估计性能研究

Simulations of broadband multipath signals for vector hydrophone and the orientation performance study

以声线理论为基础,建立了发射波形已知的声场振速信号的有限差分数值计算模型。在保证精度的前提下,仿真宽带信号所需的计算量和运算时间都大大减少,可满足实时处理的需要。通过仿真分析了浅海环境下近、远场的多途信号的到达结构及其对矢量水听器俯仰角定向性能的影响。研究结果表明:多途相干信号给矢量水听器的俯仰角估计带来严重误差,应该寻求匹配场处理或者其它信号处理技术提取直达波以改善其性能;使用等声速剖面近似弱负梯度声速剖面,对声压信号和垂直振速信号时域波形影响较小,但对水平振速的时域波形影响很大。

A finite difference model for acoustic velocity signals based on ray theory is proposed when the emitted signal waveform is known. The computation time is reduced significantly in the case of broadband signals at the tolerance of accuracy. Simulations are conducted in shallow waters to analyze the arrival patterns of multipath signals at short and long ranges and its influence on the elevation estimation performance of the vector hydrophones is analyzed. The results show that the multipath coherent signals severely degrade the estimation performance of the vector hydrophones, and thus matched field processing or signal processing techniques to pick up the direct arrival signals should be used to im- prove the performance. Using the iso-speed profile as an approximation to the weak negative gradient sound speed profile （SSP） influence little on the waveforms of pressure and vertical velocity signals, but greatly on the waveform of horizontal velocity signals.