Research On Vehicle Micro Inertial Navigation Algorithm Under GNSS Short Time Unlock

Aiming at the problem that the Inertial Navigation System(INS)error will be rapidly diverged when the Global Navigation Satellite System(GNSS)is unlock in a short time in the GNSS/INS navigation system.This paper studies the vehicle navigation related algorithm based on the Micro-Electro-Mechanical System(MEMS)inertial device,and has achieved some effect.In this paper,firstly,INS principle is discussed,and the attitude,velocity,position updating equations and the corresponding error equations are deduced.The sensor data fusion technology and the Kalman-based optimal state estimation theory are introduced in detail.Then,the measurement unit of the MEMS inertial device is integrated and tested,and according to its characteristics,a calibration method for the deterministic error of the MEMS accelerometer and a random error compensation method for the MEMS gyroscope are proposed respectively.The ellipsoid fitting idea is adopted in the MEMS accelerometer calibration scheme,and the essence is to get the relevant calibration parameters from the geometric relations and the optimal ellipsoid parameters.In the MEMS gyroscope random error compensation scheme,the idea of random time series model approximation is adopted,and Fast Fourier Transform(FFT),auto correlation function analysis,and Allan analysis are also used.Next,an autonomous vehicle navigation algorithm under GNSS out of lock condition is designed.Firstly,a rough alignment scheme is given on the stationary based.Then,the problems of the autonomous navigation algorithm are analyzed effectively,the attitude estimation algorithm based on three sample rotation vector updating the Extended Kalman Filter(EKF)and the navigation positioning estimation algorithm based on kinematics are proposed.The modeling process is derived in detail,and the general conclusion is given.Finally,the hardware test platform of the vehicle navigation system is built,and the attitude and positioning accuracy test are designed which based on the turntable and high precision positioning and orientation system.The experimental results show that the designed vehicle micro inertial navigation attitude and location estimation algorithm can effectively compensate the error when the GNSS is unlocked in a short time.The precision of autonomous vehicle navigation is improved.