Study On The Calibration Method Of High Precision Fiber Optic Inertial Measurement Unit

The optical fiber gyroscope inertial measurement unit(hereinafter referred to as the optical fiber inertial group)in strapdown inertial navigation system has the advantage of improving the precision of navigation.In order to improve the calibration accuracy,we choose the high-precision fiber optic inertial group as the research object in this paper.We calibrate the turntable and optimize the calibration method respectively.1.On the basis of the three axis turntable,this paper studies the vertical calibration method.The mathematical model in this paper is based on the characteristics of the inertial group and its name is a gyroscope and an accelerometer model.The mathematical method corresponding to this model is the rate method and the twelve position method.This method is used to calibrate,and then through the optimal estimation theory,we find out the calculation method of calibration parameters.The experiment and calculation are carried out by this method,and the results show that the algorithm is correct and effective in the optical fiber inertial group calibration.2.The influence of the error caused by the turntable on the calibration accuracy is described in detail.The mathematical model used is the direction cosine and the four element number theory.On the basis of the calibration method described above,the relationship between the error and the calibration coefficient produced by the turntable is calculated.The two methods are verified by theoretical analysis and computer simulation.The results show that the order of the turret error and calibration parameter is not affected by the turntable.3,a new method based on the fitted hexahedron,extending the IMU calibration process,through experimental analysis and determination of hexahedron material tooling method error of calibration influence,using the numerical quantification method of accurate analysis of influence of precision,on the basis of IMU calibration parameters of high precision determination.The calibration experiments of regular hexahedron tooling and turntable show that the accuracy of the two calibration methods is basically the same,and the high accuracy hexahedral tooling is simpler and more effective.Therefore,this method can be used for high-precision fiber optic inertial calibration.