Loop gain stabilizing with an all-digital automatic-gain-control method for high-precision fiber-optic gyroscope.

Area of Science:

• * Instrumentation and Measurement
• * Optical Engineering
• * Control Systems

Background:

• * Fiber-optic gyroscopes (FOGs) utilize electronic dithers to suppress dead zones.
• * Inaccurate loop gain in FOGs leads to dither residuals and navigation errors.
• * Existing methods struggle with accurate compensation without a fixed loop gain.

Purpose of the Study:

• * To propose an all-digital automatic gain control (AGC) method for stabilizing FOG loop gain.
• * To eliminate dither residuals and improve the accuracy of FOG rotation rate output.
• * To provide a stable loop gain for high-precision FOG applications.

Main Methods:

• * Implementation of an all-digital automatic gain control loop within the conventional FOG control loop.
• * Utilizing a perturbation square wave to accurately measure the FOG's loop gain.
• * Ensuring the measured loop gain converges to a predefined reference value.

Main Results:

• * Successful elimination of dither residuals even with a 20% variation in loop gain.
• * Significant reduction in the standard deviation of FOG sampling outputs from 2.00 deg/h to 0.62 deg/h.
• * Demonstrated stabilization of loop gain across operational temperature ranges and over extended periods.

Conclusions:

• * The proposed all-digital AGC method effectively stabilizes FOG loop gain.
• * This technique significantly enhances FOG accuracy by removing dither residuals.
• * The method lays a foundation for reliable, high-precision FOG engineering applications.