Research On Targeting Technology Underwater Based On Stoneley Wave

Seismic waves underwater are caused by target vibration underwater,but a few studies about underwater target location have been conducted by seismic wave,it is a relatively new area of research.Body waves and surface waves are included in seismic wave underwater.Surface waves are mainly composed by stoneley wave.The stoneley wave have the low frequency,high energy and transmission distance characteristics.According to these characteristics of stoneley wave,it will have high research value in the vibration target location underwater application.At present the active and passive methods are mainly used in vibration target location underwater.A kind of passive location method is adopted in this paper,because of good concealment and less energy consumption advantages in the passive location method.In use of stoneley wave to vibration target location underwater,first of all,set up the underwater target vibration signal model based on stoneley wave,and the vibration target underwater signal acquisition system is designed.A large indoor pool are simulated the real underwater environment in the acquisition system,and the right type of acceleration sensor,acquisition card and signal conditioning device,personal computer with pre-installed software LabVIEW application are chosen as major components in the acquisition system.Because of the complex underwater environment all kinds of interference are contained in vibration signal acquisition,so the vibration signal preprocessing underwater is designed,get rid of zero drift and filter out noise through preprocessing.Secondly,after studying the basic theory of fractal dimension and primary wave,using the window of fractal dimension method to extraction primary wave,in view of the stoneley wave,joint time-frequency domain analysis method is studied,then the wavelet transform and smooth pseudo Wigner Ville distribution are used to extraction the stoneley wave and determine the primary wave and stoneley wave arrival time difference.At last the time difference and locating separation method is adopted in this paper,the vibration target underwater ranging and direction finding are separation.By the time difference method to range the vibration target underwater,combined with a cross array layout of five sensor underwater vibration target direction finding,finally get the vibration target location underwater.Through the experimental data validation,the time difference and locating separation method has been achieved more accurate positioning results,proves that the method is feasible.