Zero-velocity Update Algorithm Of Laser Gyro Strapdown Inertial Navigation System Mounted On Vehicle

The strapdown inertial navigation system(SINS)can satisfy the concealment and autonomy of the land-based combat vehicle navigation system,but it has the inherent disadvantage of a sharp decline in navigation accuracy with time.The higher the accuracy of IMU,the higher the accuracy of navigation,but the higher the corresponding cost.How to make the medium precision IMU achieve the high accuracy navigation effect is the most fundamental starting point of this research.Based on the existing strapdown inertial navigation equipment,the initial alignment algorithm and zero-velocity update algorithm are studied to improve the navigation accuracy of the system.In the research and design process of the initial alignment algorithm,the rough initial attitude angle is obtained by the analytic coarse alignment.Then the open loop Kalman filter model is established based on the SINS error equation,and the observability criterion and analysis method of the system state are proposed.The closed loop Kalman filter model is established by using the split system as the nominal subsystem and the error subsystem.Finally,by comparing the navigation error of the same data at the same time to indirectly verify the alignment precision of open loop Kalman fine alignment and closed loop Kalman fine alignment.In this paper,the zero-velocity update technology based on the open loop Kalman filter theory is studied,the zero-velocity update algorithm is explored,the IMU error model of the Kalman filter is established,and the state observability analysis of the system is carried out.Then,the static test is designed,the parameter setting method of Kalman filter is debugged and summed up.Finally,the reliability of the zero-velocity update algorithm is verified,and the navigation precision is improved by the 1 or 2 orders of magnitude.In this project,we have designed and conducted a real roads traffic test,and completed off-line data analysis.In order to adapt the zero-velocity update algorithm to the dynamic condition,a zero-velocity detector capable of detecting whether the vehicle is stopped or not is designed.Four sets of real roads traffic tests have been done,which correspond to two different parking time intervals and random parking time intervals,and two sets of experiments were conducted for one of the parking time intervals.Finally,the reliability and repeatability of the zero-velocity update algorithm are verified.