低频矢量声场建模及其应用研究

Modeling and applications of vector acoustic field at low frequencies

浅海近距离矢量声场携带了丰富的信息可以用来识别目标。采用射线理论对浅海低频矢量声场进行建模,并且分析了该模型在浅海或深海低频时的适用性。经过与波动理论的比较,说明该模型仅是矢量声场传播损失的简单近似。通过分析浅海声压场的特性,提出了一种目标运动参数估计的方法,海试数据分析说明了其有效性。近距离目标辐射的低频宽带噪声通过浅海声场后,在LOFAR图上形成双曲线干涉条纹。运用图像处理中边缘提取的常用方法——Hough变换,提取双曲线参数,可以得到运动目标的航速、航深及距离的信息。

Short-range vector acoustic fields in shallow water carry abundant information for target classification. The ray model is used to describe the low frequency acoustic field in shallow water. Applicability of this model in shallow water or deep water at low frequencies is checked. A comparison between the wave and ray models shows that the ray model gives an approximation of the transmission loss in an acoustic vector field. An analysis of the ray model provides a method to estimate the motion parameter of the object with the validity verified by experiment results. The acoustic field of wideband noise at low frequencies radiated from a short-range moving object in shallow water forms a hyperbolic interference pattern in LOFAR. With the Hough transform, often used in image edge detection, the hyperbolic parameter in LOFAR is obtained so that the speed, depth and the distance of the moving object can be estimated.