谐振式光学陀螺数字锁频精度优化设计

Optimization Design of the Digital Frequency-Locking Accuracy of the Resonant Optical Gyro

环境温度等外界因素引起的互易性噪声极易改变谐振式光学陀螺中光波导谐振腔特性,对陀螺系统测试产生极大影响。利用高精度的激光频率锁定技术对陀螺系统中的互异性噪声进行有效抑制,提高了陀螺性能。根据谐振式光学陀螺系统工作原理,分析建立激光器锁频闭环回路模型,通过程控运算放大电路改变控制增益,优化激光器电流调谐的控制精度,实现了闭环回路锁频精度的提升与系统中的互异性噪声的抑制。通过搭建的谐振式光学陀螺系统平台测试得到,锁频精度可提高近一个数量级,最终成功将频率锁定精度提升至6.3°/h,陀螺长期零偏稳定性达到31.26°/h。

The optical waveguide resonant cavity characteristics of the resonant optical gyro are easily changed by the reciprocity noise caused by the external factors, such as the environment temperature, therefore greatly affecting the measurement of the gyro system. The performances of the gyro were improved by the effective suppression of the reciprocity noise in the gyro system with high precision laser frequency-locking technology. According to the working principle of the resonant optical gyro system, the laser frequency-locking closed-loop model was analyzed and es- tablished. The improvement of the closed-loop frequency-locking accuracy and the suppression of the reciprocity noise in the system were achieved by changing the control gain of the process-con- trolled operational amplifier circuit and optimizing the control precision of the laser current modu- lation. The frequency-locking accuracy can be increased by an order of magnitude through the measurement with the built resonant optical gyro system platform. The results show that finally the frequency-locking accuracy is successfully improved to 6.3°/h, and the long-term zero-bias stability of the gyro reaches 31.26°/h.