Research On Several Key Techniques Of Autonomous Acoustic Navigation For Underwater Unmanned Vehicle

Underwater unmanned vehicle,as an important means of exploring the ocean,has been widely used in civil and military fields.One of the key technologies of UUV engineering and practicality is underwater navigation technology.Underwater acoustic navigation technology plays an important role in Underwater Unmanned Aerial Vehicle Navigation because it can provide absolute coordinate information in real time,taking into account both deep and shallow seas.How to improve the navigation accuracy and ensure the stability of navigation data is the key and difficult point of acoustic navigation technology.This paper focuses on the autonomous navigation of Unmanned Underwater Vehicle based on long-baseline acoustic navigation technology,focusing on the key technologies such as navigation positioning model and solution method,sound line correction method,autonomous and reliable tracking method,in order to provide technical support for real-time,high-precision and reliable autonomous navigation of UUV.With regard to the navigation and positioning model and its solution,aiming at the active positioning and passive positioning modes in long-baseline acoustic navigation,the model mismatch errors caused by UUV motion in traditional navigation model are discussed respectively,and the corresponding improved navigation and positioning model is proposed.The linear solution method and optimization solution method for model solution are also studied.The theoretical deduction process and simulation results of the above research are given in this paper.The simulation results verify the effectiveness of the improved model and solution method.For the problem of sound line correction,based on the mechanism of the influence of sound line bending on the accuracy of acoustic navigation,this paper studies the effective sound speed estimation method based on the eigenvalue search method of Gauss beam under the earliest arrival criterion,analyses the spatial variation characteristics of the effective sound speed in shallow and deep seas,and discusses the sound line correction method based on the effective sound speed.The simulation results show that the method can significantly reduce the navigation error caused by the bending of the sound ray.With regard to autonomous and reliable tracking,aiming at the problem that UUV navigation data are greatly affected by platform noise,external interference,large error of realtime navigation data or may have outliers,two track tracking methods,standard Kalman filter and grey adaptive filter,are studied through theoretical and simulation analysis.The results show that both methods can effectively track the trajectory,but the standard Kalman filter method has a strong dependence on the selection of maneuvering moving target model,while the grey adaptive filter method does not need the maneuvering moving target model and noise statistical characteristics.The method is relatively simple and has good real-time performance.Finally,this paper deals with the measured data of the sea test,calculates the effective sound velocity under the measured hydrology,and gives the comparative analysis results of the navigation trajectory,tracking results and accuracy between the active positioning and passive positioning modes.The data processing results verify the feasibility and validity of the above methods.