Research On Calibration Technique Of The Strapdown Inertial Navigation System

The paper is based on the research and development of the project named "SINS(Strapdown Inertial Navigation System) Based on FOG(Fiber-Optic Gyroscope)". The study mainly deals with the calibration test techniques of SINS.In SINS, since the inertial sensors are direct mounted on the body, the sensors endure the angle motion, and the inertial sensors' error of SINS is much more than the error of platform system. Error compensation is an efficient way to enhance the accuracy of navigation, but error calibration is the precondition of error compensation.Based on the different of the measurements, calibration of SINS consists of separate calibration and system grade calibration, separate calibration is classic and in common use now. System grade calibration development from 1980s, it represents the important heading of calibration technology. But traditional system grade calibration uses the velocity errors as the Kalman filter measurements, it has the disadvantages as the lack of measurements, large burden of calculation, etc, and so it is hard to be used in project.Combining the engineering practice, the paper presents a SINS' online combined calibration method based on the high-accuracy multifunctional three-axis turntable. Above all, according to the FOG and quartz accelerometer adopted in navigation system, the static error models of IMU(Inertial Measurement Units) are built up. Then SINS' online combined calibration method adopts the recursive least squares method to deal with test data. Test process is simple, and it improves the automation level of calibration.The availability and applicability of SINS' online combined calibration method are proved through the simulation of software and the experimentation.