Research On High Precision Correction Method For Fiber Optic Gyro Temperature Drift

As a new type of optical inertial navigation instrument,the fibre-optic gyro combines the relevant technologies from the fields of optics,electronics and navigation,and is rapidly becoming an important research direction in the field of navigation with its advantages of simple structure,high measurement accuracy and low cost.In practical engineering applications,the fiber optic gyro needs to adapt to complex working environments,including shock,vibration,high and low temperature,etc.Among them,the zero bias instability brought about by temperature fluctuations is the main factor leading to output accuracy degradation and navigation system deviation,so solving the temperature drift error of the fiber optic gyro is a key technical problem that needs to be solved in this field.Researchers at home and abroad have studied the temperature drift error compensation of optical fiber gyro,mainly from the mechanism,temperature control and algorithm level,but the first two types of compensation accuracy is limited due to process limitations and engineering adaptability,so based on software algorithm to build a model to compensate the temperature drift error of optical fiber gyro is an efficient technical way.This paper proposes a polynomial fitting based drift correction algorithm for temperature variation based on the construction of a temperature drift error model for the fibre optic ring to correct the temperature drift of the fibre optic gyro with high accuracy.This paper firstly briefly describes the development status of high precision fibre optic gyro and related key technologies,and compares and analyses the research status of fibre optic gyro temperature error compensation technology at home and abroad.The paper then describes in detail the principle of Sagnac effect and typical performance indicators of interferometric fibre optic gyro,and discusses the effect of temperature fluctuations on the performance of the main components of the fibre optic gyro.The principle of the non-reciprocal error of the fibre-optic ring affected by temperature is studied,and the transfer relationship between the non-reciprocal error and zero bias of the fibre-optic ring is analysed in depth.A heat transfer model of the fiber ring with the turn as the discrete unit is developed using COMSOL software,and the thermally induced rotational rate error of the fiber ring under full temperature conditions is analyzed.The temperature excitation process was divided into cooling and heating stages,and the magnitude of the thermotropic rotation rate error for the same temperature at different stages was analysed.The difference in the thermogenic rotation rate error between the radial and axial temperature excitation was then analysed by applying the temperature excitation to different positions of the ring.Finally,the rate of change of the external temperature was varied and the relationship between the rate of change of temperature and the thermal rotation rate error of the ring was analysed.Establish a zero bias error compensation model for the cooling/warming stage with a step size of 0.2 ℃/min and an upper limit of 1 ℃/min.Based on the relationship between the temperature change rate of the fiber optic ring at each stage and the temperature change rate of the external environment,the change process is divided into three sub models for fitting to improve the compensation accuracy.The simulation results verify that the three segment model established by mixed radial and axial sampling has a high compensation accuracy,and after compensation,the fiber ring bias error is reduced by about two orders of magnitude.The model algorithm is simple and suitable for engineering applications.