Research On Time Delay Estimation Methods In Underwater Acoustic Signal

With the understanding of the ocean in the civilian and military strategic significance deeply,more and more resources are all used for marine development and military equipment,The first step in understanding the ocean is confirmed the presence of the object and determine its position,whether civil or military,so the key technology of underwater acoustic is detection and location technology.At present,the most commonly used in underwater acoustic positioning technology is the time delay estimation technique.Time delay is one of the important parameters to characterize the signal.Accurate,rapid estimation of delay and other parameters can further determine the source distance,direction,speed and other information.Therefore,estimating the time delay parameter is a research issue in the field of signal processing research is very active.Based on the analysis of time delay estimation based on the present situation of development,and summarizes the theory and method of time delay estimation,the methods such as generalized cross correlation time delay estimation based on cross spectrum method,time delay estimation,and analysis and comparison of the method of time delay estimation performance,pointed out the direction of research for time delay estimation.To sum up,the main content of this paper include the following aspects:(1)summarizes the development of time delay estimation and time delay estimation in the application in the research of underwater targets,introduces the principle of time delay estimation and time delay estimation in various fields of application,especially used in the target orientation of the underwater acoustic signal.(2)used for time delay estimation is introduced in the calculation of time delay estimation method based on time delay estimation method,the theoretical analysis and performance characteristics of their respective.(3)the passive sonar signal and jamming,using MATLAB simulation,simulation of the generalized cross correlation time delay estimation and cross spectral method of time delay estimation,analyzes the different effects estimated in the weighted function and different signal to noise ratio of delay.(4)this paper introduces the classification of underwater array.In this paper,a method is proposed to estimate the time delay of underwater multi channel array,using the average generalized cross-correlation method can estimate the time delay of multi channel array,and the simulation results show that this method can greatly improve the accuracy of time delay estimation.(5)implementation of the test system mainly introduces the acoustic time delay estimation.Firstly,the acoustic time delay estimation principle test system is introduced briefly,and then introduced the system consists of four parts,at the end of the time delay estimation test system to do the error analysis.(6)tested in anechoic pool and lake,performance comparison of correlation method and cross power spectrum method,because of the complexity of the environment noise of ship radiated noise and under the water,experimental results show that the cross power spectrum method,cross-correlation method has great ability to adapt to the environment and high estimation accuracy.