水下小目标中低频声散射特性分析及试验

Analysis and Test of Low-/Mid-Frequency Acoustic Scattering Characteristics of Small Underwater Target

自主探测与识别水下小目标(水雷、爆炸物等)是自主水下航行器(AUV)的主要应用方式,也是近年来水下无人系统智能化发展的一个重要方向。与传统的仅利用目标高频反向散射特性的探测方法相比,双/多基地探测具有布阵灵活、抗干扰强、可获得的目标信息丰富等优点,但如何利用目标中低频全方位的散射特性进行探测与识别还有待进一步研究。文中首先分析了水下目标的声散射机理,介绍了利用AUV搭载的小孔径声呐,采用双基地模式,基于目标散射声场探测与识别水下小目标的方法;然后基于COMSOL多物理场平台的有限元数值计算方法,完成了多种频率的水下悬浮目标散射声场计算,论述了利用中低频散射场的三维特性识别水下目标的可行性;最后通过2种类型目标的散射声场采集水池试验,初步论证了利用小孔径声呐采集与处理中低频水下目标散射声波是可行的。文中研究可为基于中低频声散射特性的检测和识别的进一步研究提供参考。

Autonomous detection and identification of small underwater targets(such as mine and explosives)is one of the main applications of autonomous undersea vehicle(AUV),and is also an important development direction of intelligentization of unmanned undersea systems in recent years.Compared with the traditional detection method that only uses the high frequency backscattering characteristics of the target,bistatic/multistatic detection has the advantages of flexible array arrangement,strong anti-interference performance and abundant available target information,etc.To make use of the omnidirectional low-/mid-frequency scattering characteristics of targets for detection and identification,the acoustic scattering mechanism of underwater target is analyzed theoretically,and the method of using the AUV-borne small aperture sonar with bistatic mode to detect and identify small underwater target based on the scattered acoustic field is introduced.Then,based on the finite element numerical calculation method of the COMSOL multi-physical field platform,the scattered acoustic field calculation of underwater suspended target with various frequencies is completed,and the feasibility of using the three-dimensional characteristic of low-/mid-frequency scattered field to identify underwater target is discussed.Finally,the feasibility of using small aperture sonar to collect and process the low-/mid-frequency scattered acoustic waves of underwater targets is demonstrated through water-tank experiment of scattered acoustic field collection of two kinds of targets.This study may provide a reference for further research on detection and identification based on the characteristics of low-/mid-frequency acoustic scattering.