Research Method For Extending The Dynamic Range Of Closed-loop Fiber Optic Gyroscope

As a kind of angular rate sensor applied in inertial navigation system,fiber optic gyroscope(FOG)has advantages such as low cost,long life time,large dynamic range and etc.It can start up in a short time and work in vibration surroundings without rotating device,which enable that it can be widely utilized in military as well as civil fields.However,with the development of fiber optic gyro,a requirement for higher precision will inevitably lead to the reduction of the dynamic range,which will seriously limit its applications in high dynamic range conditions.This paper expects to extend the dynamic range of fiber-optic gyro to meet the requirements of more applications by adding auxiliary gyroscope.The main work of this paper is listed follows:Firstly,the development of FOG and the importance of extending the dynamic range of FOG are illustrated.The paper will introduce and analyze the deterioration of current methos for enlarging the dynamic range.Then the description of how the digital closed-loop fiber optic gyroscope and each module works are stated.Finally,the mathematical model of fiber optic gyro system is established.Secondly,the analysis is performed on dynamic range of closed-loop fiber optic gyroscope.And the rate error caused by large angular velocity is indicated in the paper.Then the MATLAB simulation for fiber optic gyroscope is established based on the mathematical model.The paper verifies the rate error through the simulation and obtains the maximum of angular acceleration in which condition system can work normally.Thirdly,the principle of MEMS gyro and the simulation model is introduced.On this basis,a scheme that increases dynamic range of the closed-loop FOG through assisted MEMS gyroscope is proposed in this paper.Finally,the experiment is designed and conducted which verifies the existence of the error caused by large angular rate input.In addition,the maximum of angular acceleration and the reliability of the MEMS gyroscope in the proposed scheme are tested.The results indicate that the maximum value of angular acceleration show great agreement with the simulation result and the MEMS gyroscope can be used in the project presented in the paper.Eventually,the simulation is optimized by calculate the real parameters through experimental data.