相位检测误差对核磁共振陀螺输出频率的影响

针对核磁共振陀螺中采用相位检测方案时可能引起额外频率误差的问题,提出了通过控制电子顺磁共振失谐量及静磁场扰动来抑制额外频率误差的方案。基于Bloch方程,推导了惰性气体原子系综输出频率的表达式,并将相位检测的过程包含在内。建立了考虑相位检测误差的核磁共振陀螺频率误差方程,给出了相位检测引入的额外频率误差表达式并进行了数值仿真。仿真结果表明,通过设定合适的共振失谐量,其额外频率误差至少可以抑制1个数量级,而通过精确地抑制静磁场的一阶及二阶扰动,可以进一步抑制1～3个数量级,将额外频率误差降低到nHz量级。

The Impact of the Phase Detection Error on the Output Frequency of the Nuclear Magnetic Resonance Gyroscope

Regarding the problem of the additional frequency error possibly induced by the applied phase detection method in the nuclear magnetic resonance gyroscope, a new scheme to suppress the additional frequency error is put forward by monitoring the electron paramagnetic off-resonance quantity and the static magnetic field fluctuation. The Bloch equation based expression of output frequency for the noble gas atomic ensemble is deducted, with the impact of the phase detection method included. The phase detection error included frequency error equation of the nuclear magnetic resonance gyroscope is established, and the accordingly expression of the phase detection induced additional frequency error is given, with which the numerical simulation is presented. The simulation results indicate that the additional frequency error could be suppressed by at least one order of magnitude by properly setting the value of the off-resonance quantity, while further one to three orders of magnitude suppression could be achieved by accurately monitoring the first and second order fluctuation of the static magnetic field, which leads to the predicted additional frequency error of sub-nHz magnitude.