Research On MEMS-IMU/GPS Tightly Integrated Navigation Method

The compact integrated navigation system based on MEMS IMU inertial navigation system(INS)and global positioning system(GPS)can not only solve the problem of insufficient number of visible satellites,but also has the advantages of low cost and high performance,making it one of the hot issues in current navigation research.The key problem to realize the combination of the two subsystems is how to perform data fusion on the information provided by the two subsystems.Therefore,the research of data fusion technology is of great significance to improve the performance of integrated navigation system and realize high accuracy and reliability of navigation positioning.With lower cost of MEMS inertial device,the accuracy of inertial navigation system is low,the integrated navigation system,attitude Angle error correction effect is not ideal,make the system can't run to keep high precision for a long time,when accumulated to a certain degree,the attitude Angle error can lead to tight combination filter divergence,so the attitude Angle error measurement calibration is necessary.The main content of this paper is as follows:Firstly,the development of integrated navigation and attitude measurement is introduced briefly.This paper describes the definition of commonly used navigation coordinate system and the transformation relationship between commonly used coordinate system,as well as the basic working principle of GPS navigation system and inertial navigation system.The combination of inertial navigation system and satellite navigation system and the characteristics of each mode are introduced.Secondly,the basic concept and filter model of kalman filter are introduced.For the inertial navigation and satellite navigation tightly-combined navigation system studied in this subject,the kalman filter model is established,and the state equation and measurement equation of the system model are derived in detail.The simulation results show that the closed loop filtering structure of the compact combination system has better performance than the open loop filtering structure,and the compact combination system can still provide high accuracy positioning results when the number of visible satellites is insufficient.Then,the method and principle of adopting GPS receiver for carrier attitude measurement are introduced,and how to use single antenna GPS receiver for pseudo-attitude Angle calculation is introduced in detail,Kalman filter technique is used to estimate the optimal solution data.The simulation results show that the single antenna GPS receiver can be used to calculate the attitude of the carrier.Finally,in the traditional inertial/satellite tight integrated navigation system,the attitude Angle measurement obtained by the calculation of single antenna GPS receiver is introduced,and the tight combined attitude correction algorithm is designed,and build a modular integrated simulation platform.The simulation results show that the proposed algorithm can solve the error accumulation caused by unobservable attitude Angle error,make the filter stable and provide more accurate navigation information.