Study On Dual-Species NuclearMagnetic Resonance Gyroscope WithPolarized ¹²⁹Xe And ¹³¹Xe Noble Gas

As one of the core devices in inertial navigation system,gyroscope provides carrier rotation angular velocity and angular displacement for inertial navigation system.The autonomy and safety of inertial navigation make the gyroscope important in civilian navigation and military fields.The NMR gyroscope studied in this paper belongs to the third-generation gyroscope.It has the characteristics of small size,high accuracy and low energy consumption.In this article,we studied the NMR gyroscope with ⁸⁷Rb-¹²⁹Xe/¹³¹Xe as the working substance.In order to better understand the working principle of nuclear magnetic resonance gyroscope,we started from ⁸⁷Rb atomic energy level,introduced the process of light absorption,light pumping and spin exchange.Furthermore,a dynamic model was established to describe the inert gas magnetic resonance process,and the expression of the inert gas polarization vector under steady state was given.In order to measure the polarization vector of inert gas,we introduce the optical rotation effect and the detection process using ⁸⁷Rb atom as a magnetometer,and give the theoretical formula of the detection signal.In order to make the NMR gyroscope have a good working environment,this paper designed a combined coil to improve the uniformity of the static magnetic field,and the use of high-frequency heating to reduce the magnetic noise introduced during the heating process.According to the composition of the gas chamber,the absorption cross section and scattering cross section of the atom are calculated,and the optimal working frequencies of the probe light and the pump light are obtained and verified experimentally.The article optimizes the size of the driving field at different temperatures according to the relaxation time,so that the inert gas resonance signal achieves the maximum signal-to-noise ratio.By calculating the relationship between gyro response and relaxation time,the relaxation time at different temperatures was measured.Combining gyro response and signal-to-noise ratio,the article uses the scale factor to determine the optimal working temperature of the gyro is100?.Finally,we give the advantages of the dual working material NMR gyroscopecompared to the single working material NMR gyroscope,and its zero bias stability can be improved by two orders of magnitude.