Research On The Calibration Method Of MEMS Gyro Strapdown Inertial Navigation System

Micro inertial technology grows up quickly in recent years, and it has become an important branch of navigation technology. The small SINS based on MEMS gyroscope has small size, low cost, high degree of integration, independence and other characteristics, which plays an important purpose on the military defense and the national economy. With the MEMS industry and IC manufacturing technology develops, MEMS gyroscope has a trend to substituted for other low-accuracy gyro. There are many relevant agencies at home and abroad have attached great importance to the development and application of micro-inertial navigation system.As the common MEMS-IMU has a low performance, the study of how to improve the measurement accuracy of MEMS-IMU has great practical significance. A mathematical model of the MEMS gyroscope is established, and its calibration and compensation is an important way to improve the performance of MEMS Inertial Measurement Unit, the paper mainly studies error modeling and calibration compensation for MEMS-IMU.First of all, illustrates the basic theory of SINS and common coordinate system and its transformation. Conduct the error characteristics of MEMS-IMU analysis to study the influence of the error of SINS. Random noise of MEMS-IMU has a great impact on the accuracy of the IMU. This paper adopts the Allan variance method to evaluate the size of the various noise sources.Secondly, according to the characteristics of the MEMS-IMU, MEMS-IMU error model is established, and discrete calibration of MEMS-IMU is used. Based on three-axis turntable designed rate calibration test and static multi-position test, the calculation method of model parameters is given, and combined with the simulation test to verify calibration method is practical. Then illustrate the calibration of model parameters caused by the turntable error.Then, in view of the problem that the accuracy of discrete calibration relies on turntable, while calibration in system level theory of MEMS-IMU was studied, The Kalman filter is designed according to the navigation error equation. And the calibration in system level of MEMS-IMU has carried on the simulation experiment.Finally, in the turntable experiment, illustrating the systematic calibration method can improve the accuracy of the calibration by contrast discrete calibration and systematic calibration results. Systematic calibration method reduce the MEMS-IMU calibration dependence on the turntable, it will help improve the accuracy of the MEMS-IMU to meet the application needs of the field of low accuracy.