基于等效输入的光纤陀螺带宽自主测试方法

Self-test method for bandwidth of fiber optical gyroscope based on equivalent input

针对光纤陀螺频带测试角震动台输入频率低的问题,通过在光纤陀螺反馈阶梯波上叠加正弦信号用于等效外部输入角速度,对陀螺解调输出信号按照幅值进行判断得到陀螺带宽。分析了输入等效正弦波幅值满足条件;针对正弦信号在相位调制器上调制产生的相位差随频率变化的缺点对相位差幅值进行补偿;提出了利用直接数字合成技术生成正弦波信号和极值搜索算法检测信号幅值的带宽检测方案,利用陀螺自身硬件基础实现自主检测。通过建立数字闭环光纤陀螺模型,利用Simulink进行了仿真分析。结果表明该检测算法能实现陀螺频带宽度的全频率范围测量,不受外部输入信号测试频率限制,能够用于光纤陀螺带宽测试。

Since the turntable＇s input frequency is low in fiber optical gyroscope＇s （FOG） bandwidth test, the output signal in gyro demodulation is estimated according to its amplitude to obtain gyro＇s band-width, and this is by adding sine waves to the FOG＇s feedback step-waves, which works as equivalent input phase signal to instead of the outside input angular velocity. The requirements for sine wave＇s amplitude are analyzed. In view of the problem that the phase differences in modulating the sine signal change with frequencies, the phase differences are compensated. A bandwidth test scheme is put forward which uses the technique of direct digital synthesizers to generate the sine signal and uses the algorithm of extremism searching to test the signal＇s amplitude. And the bandwidth test is realized mainly by using FOG＇s own hardware. By establishing the model of digital close-loop FOG, a simulation based on Matlab Simulink is carried out. It demonstrates that the test method can realize the frequency-band measurement in the whole frequency-band of FOG without being limited by the test frequencies of outside input signal.