Research On SINS/DVL/USBL Integrated Navigation System Based On Large Depth

With the development of science and technology,the requirement of precision and reliability of underwater navigation system is becoming higher and higher.Now single navigation system is difficult to meet the performance requirements.Integrated navigation technology based on multi-sensor information fusion has emerged.Integrated navigation system uses information fusion technology to improve the performance of the whole navigation system.Now the commonly used underwater navigation systems are strapdown inertial navigation system(SINS),Doppler velocity log(DVL)and Acoustic navigation system.Strapdown inertial navigation system can provide high-precision position,attitude and speed information in a short time,but the navigation accuracy decreases with time.Doppler velocimeter and acoustic navigation system can provide carrier's velocity and position information,but they are vulnerable to underwater environment.In order to satisfy the navigation requirements of deep underwater vehicles,this paper combines theme and carries out SINS/DVL/USBL integrated navigation system,and proposes a robust adaptive non-linear filtering algorithm to solve the problem of navigation accuracy reduction caused by noise mutation,abnormal measurement,state disturbance and other factors caused by underwater environmental changes.The main contents of this paper include:1.Firstly,the common coordinate systems and their transformation relations,and the earth-related parameters in navigation system are introduced.Then,according to the SINS working principle,its error is analyzed,and the non-linear model is deduced and established.Finally,according to the DVL and USBL working principle,the error of the two systems is analyzed.2.The optimal design method of integrated navigation system is studied.Two navigation subsystems SINS/DVL and SINS/USBL are designed by shallow coupling method,and their non-linear mathematical models are established.Then,the SINS/DVL/USBL integrated navigation system is designed with no-restart structure based on the characteristics of four structures of federated filtering.3.In order to solve the problem of navigation accuracy degradation caused by state disturbance,measurement error and noise mutation in large depth underwater environment,robust estimation theory is studied from the aspects of robust estimation method,category of equivalent weight function and selection of adaptive factors,and robust adaptive UKF algorithm is proposed based on the filtering characteristics of UKF algorithm.In order to further improve the accuracy of integrated navigation system,a robust adaptive UPF filtering algorithm is proposed based on particle filter and robust estimation theory.4.The proposed robust adaptive UKF algorithm and robust adaptive UPF algorithm are applied to the SINS/DVL/USBL integrated navigation system for simulation experiments.The experimental results show that the designed SINS/DVL/USBL integrated navigation system has a high navigation accuracy.When the simulation time is 370-400 s and 800-830 s,the simulation data are interfered and processed.The robust adaptive filtering can solve the problem of precision decline caused by abnormal measurement and abrupt noise change,and improve the accuracy of integrated navigation system.