High-precision and non-contact Fiber Optic Gyroscope dynamic calibration system with dual Laser Doppler Vibrometers

Abstract

Since the advantages of high precision, large dynamic range in angular velocity measurement, Fiber Optic Gyroscopes (FOGs) are recently proposed to be used as angle measuring instrument. However, in dynamic testing condition like sway, the outputs of FOGs contain inevitable angular velocity measurement error, harming angle measuring accuracy. Therefore, FOGs must be calibrated before using. In this paper, we first propose a high-precision and non-contact angle measurement method with dual-Laser Doppler Vibrometers (d-LDVs) to calibrate the angle measurement error of FOGs in sway condition. Firstly, we verify the accuracy and dynamic range of this proposed angle measurement method by using a high-precision rotary table as an angle benchmark. Experimental results indicate that this method can reach the dynamic angle measurement with the range of ±10°, and the maximum angle measurement error is less than 0.0088°. Secondly, in order to calibrate the angle measuring error of FOGs, we establish an angle calibration system for FOGs based on d-LDVs under sway condition. Experimental result shows that the dynamic angle measurement error of the FOG caused by dynamic environment is less than 0.015°. Because of the zero drift of angular velocity, integral angle of the FOG shows angle drift, and the maximum angle drift is 0.06° (during 30s).