| The Inertial navigation system(INS)is an autonomous navigation system without requiring external references or radiating energy outward.The gyroscope is one of the core sensors in the inertial navigation system.It is difficult to improve the accuracy of the conventional gyroscope currently used based on the requirement of miniaturization,which has become a bottleneck that limits the performance of the inertial navigation system.The Nuclear magnetic resonance gyroscope(NMRG)has become a new research hotspot in the field of inertial navigation because of its advantages of high accuracy,small size,low cost,and insensitivity to acceleration.This dissertation is mainly to precisely control the three-dimensional magnetic field in the nuclear magnetic resonance gyroscope,and to measure and evaluate the performance of the NMRG.Firstly,the operating principle of NMRG,including the principles of key technologies such as noble gas atomic spin polarization,noble gas atomic spin precession,noble gas atomic spin magnetic resonance and magnetic shielding,is introduced.The significance of precise magnetic field control for measuring the angular velocity of the carrier device with NMRG is pointed out.Secondly,the principle of measuring three-dimensional magnetic field by three-dimensional atomic magnetometer embedded in the NMRG is introduced,and the relationship between the slope of error signal of three-dimensional magnetic field and the key parameters,such as the static magnetic field modulation ratio and the size of oscillating magnetic field and the simulation results,is quantitatively given.After optimizing the parameters of probe light detuning,pump light detuning,static magnetic field modulation ratio,oscillating magnetic field size and static magnetic field size,the optimum working conditions are obtained.The development of three-dimensional atomic magnetometer and the closed-loop locking of three-dimensional magnetic field are realized.The sensitivities of the developed three-dimensional atomic magnetometer in x and y directions are better than 200 f T/Hz1/2 at 100 Hz,and the sensitivity in z direction is better than 20 f T/Hz1/2 at 100 Hz.After the closed-loop locking of three-dimensional magnetic field,the fluctuations of Bx,By and Bz in 6000 s are no more than143 p T,147 p T and 28 p T respectively,and the Allan deviation long stability of Bx,By and Bzfluctuations are 2 p T@1000 s,1 p T@1000 s and 200 f T@1000 s respectively.Thirdly,the various noise sources in the NMRG are introduced,and the Lab VIEW fitting program of the NMRG noise based on Allan variance analysis is compiled,and the angle random walk and bias stability of the NMRG are predicted as 0.028°/h1/2 and 1.2°/h,respectively.Finally,the experimental scheme for measuring the relaxation of noble gas atoms by the free induction decay method is introduced,and the relationship between the oscillating magnetic field size and the transverse relaxation time is explored.The gyroscopic effect of the NMRG developed in this dissertation is demonstrated,and the principle of measuring the angular velocity of the NMRG is preliminarily verified. |
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