闭环光纤陀螺方波调制失真的影响与消除

数字闭环光纤陀螺仪测量角速度时,采用方波调制引起的各种失真会对输出结果产生影响。基于傅里叶级数建立包含失真噪声的闭环光纤陀螺方波调制、解调信号模型,对各种调制失真引起的输出误差进行了仿真分析,并提出一种双极型归零脉冲方波解调方法,用于消除方波调制闭环光纤陀螺仪的输出信号误差。仿真结果表明:采用常规方波解调时,调制信号的相位失真、方波脉宽失真、谐波失真以及梳状噪声脉冲对光纤陀螺仪输出有很大影响,测量角速度相对误差可达1%量级。采用双极型归零脉冲方波解调时,上述调制失真的影响都得到有效的减小,陀螺仪测量角速度相对误差只有0.1%量级,降低了一个数量级,说明文中提出的双极型归零脉冲方波解调方法对提高闭环陀螺的测量精度和稳定性有重要意义。

Influence of square-wave modulation distortion on closed-loop fiber optic gyroscope and its elimination

Square-wave modulation with various distortion will influence the outputs of the digital closed-loop Fiber Optic Gyroscope(FOG) when measuring angular velocity. Based on Fourier series, square-wave modulation models and signal demodulation models for closed-loop FOG including distortion noise were built in this paper. Simulation studies were analyzed for the output errors caused by different modulation distortion signals. A new demodulation method of bipolar return to zero pulse of square-wave for the elimination of errors in output signals of FOG was proposed. The simulation results show that the distortions, including phase distortion, pulse width distortion, harmonic distortion and noise comb pulse, have a great influence on outputs of FOG when using conventional demodulation methods of square-wave. Measuring the relative errors of angular velocity is up to 1%. But the errors are effectively eliminated when using bipolar return to zero pulse of square-wave demodulation, and are one order of magnitude lower than the errors in conventional demodulation methods. The simulation proves that the demodulation method of bipolar return to zero pulse of square-wave is very meaningful for improving measurement accuracy and stability of the digital closed-loop FOG.