Research On Testing And Calibration Method Of MEMS Inertial Measurement Unit

With the development of micro-mechanical systems and the rapid progress of integrated circuit manufacturing technology,micro-inertia technology occupies an increasingly important position in navigation discipline.With the advantages of low cost,small size and strong autonomy,micro-inertial measurement unit(MIU)plays an increasingly important role in the field of military and civil navigation.Therefore,many research and education institutions at home and abroad pay more attention to the development and application of micro inertial system.However,the measurement accuracy of common inertial measurement units is relatively low.It is of great significance to focus on how to improve the accuracy of inertial measurement units by using scientific methods.Designing and manufacturing test calibration equipment,establishing the correct mathematical model of the inertial measurement unit of the MEMS,and designing a more simple and fast calibration test method are important ways to improve the accuracy of the inertial measurement unit of the MEMS.This paper mainly focuses on the error modeling and calibration technology of the self-made inertial measurement unit of the laboratory.Firstly,according to the requirement of calibration and testing of the inertial measurement unit of MEMS,the calibration and testing equipment made by the laboratory is introduced in detail from the aspects of mechanical structure,software and hardware design.The error characteristics of the inertial measurement unit(IMU)are analyzed,and the influence of each error parameter on the IMU is introduced in detail.In view of the fact that random noise has a great influence on the accuracy of the inertial measurement unit(IMU)of the MEMS,the Allan variance method is used to quantitatively analyze the five main noises of the MEMS gyroscope.Then,according to the characteristics of the inertial measurement unit(IMU),the error models of the gyroscope and accelerometer are established,and the discrete calibration method of the IMU is introduced in detail,and the data processing formula is deduced.Based on the self-made triaxial calibration equipment,the rate experiment of the MEMS gyroscope and the static multi-position experiment of the accelerometer were designed,and the discrete calibration experiment was carried out to verify the practicability of the method.Finally,according to the strapdown navigation error equation and Kalman filter model,the appropriate state equation and measurement equation are established,and the appropriate positioning arrangement of the system-level calibration of the MEMS inertial measurement unit is selected.According to the designed turn-stop path,the system-level calibration experiment of the inertial measurement unit of the MEMS gyroscope is carried out.The validity of the proposed calibration method is proved by test experiments.