Research On Target Localization Based On Wave Glider Platform

With the increasing demand of underwater acoustics for Marine target information,the research of sonar platform based on "cluster" has been paid more and more attention by underwater acoustics researchers.Wave Glider(WG),as a new type of ocean mobile observation platform,can realize long time,long distance ocean observation,and its low self-noise,is an ideal acoustic carrying platform.Due to the limitation of WG’s own capability,the acoustic system on WG should not be too large or too heavy,so the small scale array becomes a better choice of WG sonar.The research purpose of this paper is to carry out the research on target passive positioning technology based on the small scale quaternary scalar array mounted on the Wargaming platform,so as to provide more information for the deep recognition of the target.Firstly,considering the inconsistency of amplitude frequency and phase frequency of hydrophone,the inconsistency of amplitude frequency and phase frequency of the filtering and amplification unit of the receiving channel,and the position error of array elements in the design process of the four-element array,all of these factors will lead to the amplitude and phase error of the received signal,and the existence of relevant factors will cause the calculation error of target azimuth.Therefore,starting from the target azimuth estimation method,this paper firstly studies the basic principle of direction finding by acoustic intensity estimation method and cross spectrum method,and analyzes the correlation direction finding performance by numerical simulation.Then theoretical and numerical simulations are carried out to analyze the effects of direction finding and target frequency,azimuth Angle and array element spacing on the two direction finding methods when array element position error and amplitude phase error are introduced respectively.Then,the principle of array correction method based on auxiliary source was studied,and the validity of the method was verified by numerical simulation and sea test data,which laid a foundation for the future research on the positioning technology of WG platform based on target azimuth.Secondly,when a single Wargaming platform uses the target azimuth information to locate a target,it is generally required that the observing platform make at least one effective maneuver.In order to solve this problem,this paper starts from the method of estimating the radial velocity of target based on the acoustic field features,and gives the optimal time interval of estimating the radial velocity by using the phase acoustic field features of the linear spectrum at different target velosities with different linear spectrum frequencies through numerical simulation.Based on this,the Bearing Velocity Extended Kalman Filter(BVEKF)target location method is studied to overcome the maneuverability of the observation platform.The numerical simulation and sea trial data show that the BVEKF method can locate the target position.Finally,compared with the stationary observation platform,on the one hand,the coordinates of the moving platform change with time during the observation process,so it is worth discussing what kind of reference coordinates should be used to improve the positioning accuracy.On the other hand,the target azimuth estimation results of the mobile platform will change with the relative distance between the target and the observation platform,which will lead to the change of the BOT positioning results.Therefore,it is also worth studying what kind of BOT positioning strategy to choose.In this paper,the numerical simulation of target positioning performance of multiple WG platforms based on the number of observation platforms and the configuration of formation geometry is carried out for the typical station configuration(triangular and linear)in WG "cluster" detection.The global least squares(TLS)is applied to the location of multi-WG platforms.Through theoretical research and numerical simulation analysis,it is found that when the origin of Cartesian coordinates is selected at the geometric center of multi-WG platforms,the estimation deviation can be minimized,which is beneficial to improve the location performance of multi-WG targets.In order to solve the problem of BOT positioning strategy,the target velocity correction method is used,and compared with traditional BOT,joint target velocity estimation,Bearing Only Extended Kalman Filter(BOEKF)method in numerical simulation and sea trial data processing,the results show that the target velocity correction method has better performance.