Research On Low Cost MEMS-IMU/GNSS Integrated Navigation Algorithm

Sensors that make up inertial navigation are generally more expensive which limit its application range.MEMS inertial sensors have the advantages of mass production,low cost,small size.MEMS-IMU is an inertial measurement unit based on MEMS technology consisting of silicon micro gyroscope and accelerometer,so the low cost MEME-IMU has broad application prospects.Although its autonomy and anti-interference ability are strong,the error increases and the positioning accuracy decreases with the accumulation of time.GNSS navigation system owns wide coverage,good real-time performance and its positioning error does not accumulate over time,but it can not satisfy both antiinterference and dynamic tracking at the same time,it is easy to be occluded and disturbed,and the data update rate is low.So reling on a single navigation methods can not meet the demand of high precision,real-time tracking control of navigation.Aiming to resolve this problem,this thesis proposes a low-cost MEME-IMU/GNSS integrated navigation system to meet the needs of people with complementary advantages.The main research are as follows:Based on the navigation system.The mathematical platform required in the INS navigation algorithms of INS is calculated.Initial alignment is performed after calibration of MEMS-IMU,using quaternion and Runge-Kutta to calculate the three updating equations(posture,position and velocity)of INS navigation algorithm.In BDS navigation,the calculation position of BDS navigation is derived.To reduce the affection of low cost MEMS influenced by the inexact calibration factor error and zero bias error.To improve the accuracy of position and attitude estimation,a method of fast calibrating MEMS accelerometer based on multiposition is proposed.The experimental results show that this method can effectively calibrate the calibration factor error and zero deviation error of MEMS accelerometer.The thesis studies the combination mode of combined navigation,introduce the basic principle of UKF.Data fusion is performed by using the UKF to combine the loose combination and tight combination in the combined navigation.The error model of MEMS-IMU/GNSS integrated navigation system is derived and the system state equation and measurement equation of loose integration and tight integration are established.The simulation analysis verified that the error of combined navigation is less than that of single navigation.