数字闭环光纤陀螺的调制串扰误差

Electrical Crosstalk of Modulation Signal in Digital Closed-loop FOG

通过分析数字闭环光纤陀螺的阶梯波调制信号与输出死区、周期噪声干扰及小角速度漂移的关系,提出了调制串扰误差的概念。指出调制信号与探测器输出信号之间的电交叉耦合及调制信号产生的调制误差是产生调制串扰误差的干扰源。将调制串扰通道模型简化为比例环节和部分积分环节,并和光纤陀螺理想模型结合,建立了光纤陀螺调制串扰误差模型,利用该模型推导出了产生死区的条件及周期噪声干扰和小角速度漂移造成的输出偏差表达式,并对周期噪声的幅值、频率与陀螺输出量级、带宽之间的关系进行了定量分析。调制串扰误差的仿真和实验结果与理论分析结果基本一致,验证了调制串扰误差模型的正确性。

The electrical crosstalk error of modulation signal in a digital closed-loop fiber optic gyroscope （FOG） is proposed by analyzing saw tooth modulation signal, dead band, periodic noise and bias drift in a low rotational speed. The electrical crosstalk between phase modulator and photodetector and modulation error from the modulation signal are the main interference sources causing electrical crosstalk error of modulation signal. A model of the electrical crosstalk error of modulation signal is developed, based on an ideal FOG model and an interfering channel model simplified to proportional component and partial integration component. A condition expression of dead band and an expression of output error produced by periodic noise and bias drift in a low rotational speed are derived from the model of the electrical crosstalk error of modulation signal. The magnitude and frequency of the periodic noise and the magnitude and bandwidth of the FOG output are calculated. The model of the electrical crosstalk error of modulation signal is identified by its simulation results and experimental results.