Research On Calibration Method And Combined Positioning Technology Of SINS/DVL Integrated System

Underwater vehicle is an important carrier platform for marine resources exploration and Seabed Topography Detection,and underwater navigation technology is the key technology to ensure the system to navigate accurately and complete the work smoothly.Inertial navigation system has the advantages of high output frequency,strong autonomy and so on.It is usually used as the main navigation equipment of underwater navigation system,but it has the disadvantage that positioning error accumulates with time.Doppler velocity log(DVL)has the advantages of high accuracy,fast response,good autonomy and no error accumulation.Therefore,SINS/DVL integrated system is one of the ideal underwater navigation methods.In view of the inconsistency between SINS navigation coordinate system and DVL coordinate system,the influence of underwater environment on DVL speed measurement accuracy,and how to improve the positioning accuracy of the system,this paper studies the DVL error calibration technology in different environments and the combination positioning technology of sins and DVL,and verifies the effectiveness of the algorithm proposed in this paper.The main contents of this paper are as follows:Firstly,the development status of underwater navigation system at home and abroad,the research status of DVL error calibration technology,and the basic principles of inertial navigation positioning and DVL speed measurement are studied in detail.Based on the research of the principle of DVL speed measurement,this paper analyzes the causes of the error of DVL speed measurement and the problems in the current DVL error calibration technology.Secondly,DVL error calibration technology is studied in detail.In this paper,the problem of DVL error calibration and carrier attitude error compensation under three different conditions are studied.First of all,the DVL error calibration method based on SINS/GNSS integrated navigation is studied,and the calibration method based on velocity observation and position observation is designed.In the calibration process of installation error angle,gradient descent method and quasi Newton method are designed.Then,the two-point calibration algorithm is designed when the starting point and the ending point of the system are known,and the position parameters are solved by establishing the parameter equation.Then,the DVL error self calibration method based on specific force differential is designed when the satellite signal cannot be obtained by the carrier.At last,aiming at the influence of wave on DVL velocity error,the compensation formula of DVL velocity error is given by establishing geometric model.Thirdly,the vehicle test of SINS/DVL integrated navigation prototype system is designed.The experimental results show that the calibration accuracy of DVL scale factor error is 0.05%and the calibration accuracy of installation error angle is within 0.05 ° by using the calibration algorithm designed in this paper;when some DVL beams are missing,the SINS/DVL tight combination model can keep working normally,which improves the positioning accuracy by30% compared with the SINS/DVL loose combination model;when the DVL measurement information contains outliers,the design is based on M-estimation Compared with the standard Kalman filter SINS/DVL integrated system,the positioning accuracy is improved by about 78%.