光源强度噪声对闭环光纤陀螺输出的影响

Effect of Light Source Intensity Noise on Closed-Loop FOG Output

建立闭环光纤陀螺光路的数学模型,分析了光源光功率与陀螺灵敏度之间的关系,然后基于检测信噪比和陀螺等效噪声相位差,分析了光源强度噪声对光纤陀螺极限灵敏度的影响,最后通过建立的数字闭环光纤陀螺的Simulink仿真模型,定量分析了光源强度噪声对闭环光纤陀螺输出的影响。结果表明,由于光源强度噪声的存在,当光功率大于十几微瓦时,陀螺的极限灵敏度将趋于饱和值,对于20 nm光源谱宽的闭环陀螺,其饱和极限灵敏度为0.04(°)/h,不满足高精度陀螺的要求,而且噪声强度越大,陀螺输出的误差波动就越大,对输入角速度的跟踪效果也越差。

The relationship between the optical power of light source and the gyro sensitivity is ana- lyzed with the established mathematical model of closed-loop fiber optic gyroscope （FOG） , then the influ- ence of light source intensity noise on FOG limited sensitivity is analyzed based on the detection signal to noise ratio and gyro equivalent noise phase error, finally, the influence of light source intensity noise on the FOG output is analyzed quantitatively by the established simulink model of the digital closed-loop FOG. The results show that, due to the existence of the light source intensity noise, when the optical power is greater than a dozen microwatts, the limit of gyro sensitivity will tend to a saturation value, for the 20 nm source spectral width of the closed-loop FOG, the limited sensitivity is 0.04 （°）/h, which can not fulfill the requirement of high-precision FOG, furthermore, the more of the noise intensity, the large fluctuation of the FOG output and the worse effect of tracking the input angular velocity.