Polarization Characteristics And Temperature Performance Of Closed Loop Fiber Optic Gyroscope

Fiber optic gyroscope(FOG)has become a very important device in the field of inertial navigation,in order to improve the bias stability of FOG.In this paper,the polarization model of closed-loop FOG is established based on the polarization characteristics of each optical device in the optical path of FOG,which is a suitable evaluation method for engineering applications.By designing a filter to suppress the drift of FOG caused by temperature change,and combining with theoretical analysis and experimental research,Allan variance is used to verify the validity of the model,which can improve the accuracy of FOG.The main contents of this paper are as follows:Firstly,the polarization characteristics of each optical component of FOG are analyzed,and the polarization characteristics of the optical component are described by establishing Jones matrix and light source coherence matrix.A method is proposed to equate the polarization crosstalk points in the fiber ring with the fusion point and the tail fiber.The Jones matrix model of the polarization crosstalk points in the fiber ring is established,which is caused by the change of temperature,and the light in the loop of FOG is combined with the Jones matrix model.The optical path model of FOG is established in the direction of signal propagation.In this paper,the effects of ideal device parameters and different device parameters on polarization phase errors in fiber optic gyroscopes are simulated and analyzed.Allan variance is used to evaluate the static drift of FOG at full temperature.At last,the validity of the model is verified by comparing the predicted bias of the model with the actual bias of the experiment.It can provide an effective theoretical basis for the selection of FOG devices,the selection of the fiber ring and the design of the system.Secondly,according to the random drift characteristics of FOG at room temperature,the ARMA model is established,and the model order of FOG output sequence is determined by AIC criterion,and the applicability of the model is verified.Kalman filter and FLP filter are designed by the established ARMA model.The validity of filtering is verified by comparing the errors of static drift of FOG before and after Allan variance filtering.Finally,based on the temperature experiment of FOG,a method of secondary compensation for FOG temperature drift and error caused by temperature variation isproposed.Firstly,the drift caused by gyro temperature change is compensated by regression analysis.Then,the ARMA model is built to compensate the residual error caused by temperature.The errors before and after compensation are compared by Allan variance.The experimental results show that the method of secondary compensation for static temperature drift of FOG has practical value for improving the accuracy of FOG.