Xuyou Li

Temperature errors of IFOG and its compensation in engineering application

The temperature compensation of fiber optic gyroscope is researched in the viewpoint of the practical engineering application. The temperature characteristics of fiber optic gyroscope are analyzed, and the main factors that caused the temperature drift of gyroscope are definite. Then the temperature experiment is tested, according to the experimental results, summed up that the temperature drift error of fiber optic gyroscope is very close to the temperature change rate of fiber optic coil itself, and also in direct proportion of the temperature difference between the gyroscope shell and the central axis of coil. Based on the principles and steps of least square polynomial fitting method then the temperature drift of fiber optic gyroscope is compensated, and the order problem of polynomial compensation model is researched. The experimental results show that the zero-bias stability of gyroscope can achieve 0.0119 °/h after a 4-order temperature drift polynomial model compensating. The method is simple and reliable, and very suitable for practical engineering applications.

Establishment and theoretical analysis of mathematical model for dual-mode fiber optic current sensor

It presents a new type of fiber-optic current sensor —dual-mode fiber optic current sensor, which uses the Gouy phase shift produced by two-mode optical fiber to provide the π / 2 phase bias, and makes use of mode-selective coupler for the structural design. Based on Jones matrix, the mathematical model for dual-mode fiber optic current sensor is established, and the corresponding theoretical analysis and discussion is given finally. Gouy phase shift of two mode fiber can provide a phase bias to improve the system sensitivity and to decrease the systems error. Although the system we designed still have some disadvantages, the system of dual-mode optic fiber current sensor is very simple and flexible, which can be easily to applied to the actual environment in future.

Study on optical path modeling and error analysis of stimulated brillouin fiber optic gyroscope

The optical structure and working principle of brillouin fiber optic gyroscope was analyzed, the optical components Jones matrix model of brillouin fiber optic gyroscope was established by using Jones matrix optics theory, and the optical transfer matrix model was established based on optical transmission mechanism, the output light intensity expressions of brillouin fiber optic gyroscope and the add-beat frequency caused by optical error were deduced, The influence of main optical components error on the output light of brillouin fiber optic gyroscope was simulated and analyzed. The optical path modeling and error analysis provide a theoretical basis for the design and realization of brillouin fiber optic gyroscope.

Research on modulation stability and compensation method of Y waveguide in fiber optic gyroscope

Based on the study of the principle of ladder wave modulation in digital closed-loop fiber optic gyroscope, the temperature characteristics of Y waveguide half-wave voltage is analyzed and verified by experiment, then the influences of modulation stability of Y waveguide on fiber optic gyroscope is investigated, and the real-time tracking of compensation method for the modulation instability of Y waveguide is researched and designed. The stability of scale factor, the output interference signal during ladder wave reset period and the zero bias stability of fiber optic gyroscope are tested by comparison experiments whether the real-time tracking of compensation method is adopted. It obtained the conclusion that the modulation stability of Y waveguide is the main reasons affect the accuracy of high-precision fiber optic gyroscope, the accuracy and stability of fiber optic gyroscope has been greatly improved by adopting real-time tracking of compensation method for Y waveguide.

Simulation analysis on the influence of laser source on output of IFOG

On the base of the research object of the optical system of polarization maintaining interferometric fiber optical gyroscope(IFOG), when the light signal is modulation under +pi/2 square wave signal, an input-output model is established by making use of Jones matrix and coherence matrix. Based on the model mentioned above, theoretic analysis on the polarization noise of the optical system is made, and the polarization error expression in the case of the input low polarization light signal is deduced. Simulation analysis the gyroscope output signal and polarization noise error when the laser source performance parameters change. According to the work mentioned above, we proposed that: to design the optical system of IFOG, we should choose appropriate length of pigtail, select the light source, which the extinction ratio of itpsilas output light have high stability to reduce the zero drift to minimum.