The Research On Drift Characteristics Of Interferometric Fiber-optic Gyro IFOG

The interferometer fiber-optic gyro (IFOG) attract considerable researchers because of its distinguished performance. The drift performance of IFOG must be improved in order to apply IFOG to inertial navigation. The development of photoelectric apparatus performance and advancement of digital signal processing technology provide material foundation and technological support for restraining the drift of IFOG.The purpose of this paper is to analyze the optical characteristic of IFOG system, find out the cause of drift and discuss the compensation methods for it, which is regarde the foundation of researching high- precision IFOG. The main research work concentrates on the aspects as follows:According to the analysis of the IFOG principle, the mathematic expressions including angular acceleration were derived. The optical characteristic of all optical parts of IFOG were described and the model of closed-loop IFOG were build on interferential matrix and Jones matrix. This paper analyses these factors that bring about non-reciprocal phase drift of IFOG in detail and points out eliminating approaches. In the condition of the parameters of optic components being not ideal and fluctuation existing, the output of open-loop and closed-loop were simulated separately. The paper studies the suppressing method of IFOG 's drift in two sides: On the one side, ARIMA models of IFOG random drift were build to compensate random drift. On the other side, a transverse adaptive filter based on the LMS was designed according to the time-varying characteristic of IFOG output signals.After building closed-loop model, we can analyze and evaluate the performances of IFOG in theory, and improve it, which provide evidences for designing system and choosing optical components. The result of simulation validates the introduction of closed-loop technology enlarged the dynamic range of IFOG, enhanced its ability to anti-intervene and improve its performance. It is necessary to take into account the effects of angle acceleration and adopt compensation approaches in developing high-precision IFOG which can be applied in extremely dynamic environment. After compensating actual measured data, the result shows that adaptive filter can suppress the IFOG drift when IFOG output model is unknown.This paper investigates the drift characteristic of IFOG deeply and presents compensation approaches for it, which is meaningful to the research and development of high- precision IFOG.