Research On Spatial Radiation Error Analysis And Suppression Method Of Interferometric Fiber Optic Gyroscope

It is more and more applied for Interferometric Fiber Optic Gyroscope?IFOG?to use with its high precision,low power consumption and high reliability in attitude control system in space satellite,whose performance will become worse due to the errors caused by radiation.This paper presents a method that can reduce the space radiation error in IFOG by analyzing its mechanism of production and variation regulation to satisfy the adaption of IFOG,and design an anti-radiation digital closed-loop photonic crystal IFOG system.Finally,we make a performance test.As a result,the following achievements are finished:Firstly,a mathematical model of the radiation-induced attenuation caused by diffusion dynamics model is proposed by analyzing the radiation damage mechanism of polarization-maintaining fiber?PMF?.The intensity of radiation color center absorption in PSC-optical fiber,P-fiber,Ge-fiber and P-Ge fiber is explored through comparing the differences of radiation color centers in different doped fibers.It is clear that the intensity of radiation color center absorption is a kind of inherent property unrelated with fiber material.We go further study on common used P-fiber in IFOG that the P1 color center accounts for the main body of the whole radiation-induced attenuation by decomposing the color center of the P-fiber,whose the radiation-induced attenuation increases with increasing wavelength at1050nm-1620 nm waveband.As a result,1310 nm wavelength should be chosen when using the P-fiber in IFOG.Secondly,analyze the relation between the radiation and the errors such as polarization error,backscattering error,thermal noise,shot noise and relative intensity noises,whose is the basis of a mathematical model of the radiation errors changing with the radiation dose rate.The degeneration mechanism of the bias shift,scale factor and random walk coefficient in IFOG is further studied in radiation environment.The mathematical model of random walk coefficient is established based on radiation-induced attenuation effect on optical fiber.As a result,the reason why the bias shift and random walk coefficient degenerate is that radiation-induced attenuation.At the meanwhile,the optical wavelength drifts lead to the degeneration of scale factor.Then,design the photonic crystal fiber?PCF?used in IFOG,compare the difference between PCF and PMF in color center,radiation-induced attenuation and birefringence in radiation environment.Put forward a method that optimize the PCF IFOG system parameters through discussing the effect of optical power in light source,modulation phase and fiber length on random walk coefficient.A mathematical model of optimize the fiber length is established with the result of its1137 m length.The mathematical relation between the modulation phase and optical power is improved by studying the effect of optical power on modulation,whose the results are 1000?W optical power and 2.614 rad modulation phase and design the arithmetic of the optimizing of the demodulation signal,The proposed method for suppressing spatial radiation error is verified by comparing with others.Finally,design the anti-radiation digital closed loop photonic crystal fiber optic gyroscope through the method of suppressing the space radiation errors.And add the dynamic optimization algorithm and fault diagnosis module,whose the results are:random walk coefficient is 0.0002738°/h^1/2and the bias stability is 0.01145°/h?10s,1??.So performance indicators can meet the requirements of satellite attitude control.