基于部分解调提前反馈的光纤陀螺振动误差抑制技术

Vibration error suppression technique for a fiber optic gyroscope based on partial demodulation and feedback in advance

振动环境下光纤陀螺性能的变化称为振动误差,抑制或消除振动误差是光纤陀螺实用化的必然要求。分析了全数字闭环光纤陀螺反馈延迟对闭环跟踪性能的影响,揭示了振动误差的机理是振动环境引入的扰动不能得到较好的抑制,从而引入附加相移误差。为了抑制附加相移误差,在保证闭环稳定的条件下,提出了部分解调提前反馈方法。理论和仿真分析了不同提前反馈比例下陀螺闭环的附加相移误差,在振动测试台上实测了不同提前反馈比例时引入的附加相移及陀螺输出,结果表明增加提前反馈比例时附加相移误差减小,陀螺振动误差同步相应减小。部分解调提前反馈方法适用于不同的调制方式,可在不修改结构、光路等硬件设计的条件下提高光纤陀螺振动环境适应性。

The performance of a fiber optic gyroscope（ FOG） changes under vibration,it is called a vibration error,thus it is necessary to suppress the error for the usage of FOG. Here,the effects of the feedback delay existing in the fully digitalized closed-loop of a FOG on its closed-loop tracking performance were ananlyzed. The formation mechanism of vibration error was revealed,it was shown that the disturbances brought by vibration environment cannot be suppressed efficiently,so the additional phase errors are introduced. In order to suppress the errors,a method named partial demodulation and feedback in advance was proposed considering the stability of the closed-loop. The additional phase errors were analyzed with different proportions of feedback in advance theoretically and numerically,and the additional phases with different proportions of feedback in advance and the outputs of FOG were measured on a vibration testing table. The results showed that the vibration errors and the additional phase errors decrease simultaneously with increase in the proportion of feedback in advance; the method of partial demodulation and feedback in advance is suitable for different demodulations and it can improve the adaptability of FOG to vibration environment without modifying its hardware designs including structural design and light path design.