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Analysis of Precision Index of Fiber Optic Gyroscope

February 28, 2025

Key Points
Product: Fiber Optic Gyroscopes (FOGs)
Features:
• Highly accurate sensor for measuring angular velocity
• Low bias stability (≤0.2 °/h), ensuring high measurement accuracy
• Low random walk (ARW) for stable output over time (e.g., 0.001°/√h)
• Scale factor accuracy (e.g., 10 ppm) with minimal deviation from actual rotation
• Sensitive to temperature, vibration, and light source changes
Applications:
• Aviation: Provides accurate position, velocity, and attitude data for aircraft
• Navigation: Assists in guidance and positioning systems
• Seismic Research: Monitors rotational movement during earthquake studies
• Military: Used in missile and bomb guidance systems
Advantages:
• High precision and stability
• Low power consumption, easy installation and maintenance
• Reliable in dynamic environments with minimal drift and noise
• Versatile in various applications requiring precision angular velocity measurement

Fiber optic gyroscopes (FOGs) are highly accurate sensors used to measure angular velocity. They are widely used in fields such as aviation, navigation, and seismic research due to their high precision, sensitivity, and excellent stability. Its core accuracy indicators, including zero bias drift, random walk, and angle measurement error, are the key to evaluating its performance.

Detailed explanation of core accuracy indicators

Fiber optic gyroscope uses optical fibers as sensing elements to achieve accurate measurement of rotational angular velocity. Its accuracy performance can be comprehensively evaluated through the following three indicators:

(1) Bias Stability (Drift Rate)

This indicator reflects the output accuracy of the gyroscope in a non rotating state, usually measured by a benchmark accuracy. The zero bias drift of fiber optic gyroscope is extremely low, generally not exceeding 0.2 °/h, ensuring high measurement accuracy.

(2) Random Walk (Angular Random Walk, ARW)

This indicator measures the stability of the gyroscope output value over a period of time. typically measured in degrees per square root hour (°/√h). For example, the FOG has an ARW of 0.001°/√h. This means that the noise in the gyroscope's output accumulates at a rate of 0.001 degrees per square root of the operating time.

(3) Scale Factor Accuracy

The scale factor accuracy indicates how well the gyroscope's output corresponds to the actual angular velocity. It is usually expressed as a percentage error. For example, The FOG has a scale factor accuracy of 10 ppm (parts per million)**. This means that for every degree per second (°/s) of actual rotation, the gyroscope's output may deviate by up to 0.001%.

Analysis of Factors Affecting Accuracy

The accuracy of fiber optic gyroscopes is influenced by various external factors:

(1) Temperature:

The sensitive components of fiber optic gyroscopes are sensitive to changes in ambient temperature, which may lead to zero bias drift or increased angle measurement errors.

(2) Vibration:

Environmental vibrations can have adverse effects on the accuracy of fiber optic gyroscopes, potentially leading to unstable output values.

(3) Light source:

Changes in parameters such as power and wavelength of the light source may also affect the output value of the fiber optic gyroscope, thereby affecting its accuracy.

Example of G-F3G70 manufactured by Micro-Magic

the G-F3G70 fiber optic gyroscope inertial group is designed for medium and high precision application backgrounds. It adopts three-axis common technology and split design, with low cost and stable performance. The structure adopts optical path and circuit integrated packaging, with simple structure and easy installation. It can be used in navigation guidance, attitude measurement and control systems of small missiles and guided bombs.

Main performance index of the fiber-optic gyroscope

	G-F3G70-A	G-F3G70-B	G-F3G70-C	Unit
zero bias stability	≤0.050 (10s)	≤0.03 (10s )	≤0.02 (10s)	(°)/h
Zero bias stability full temperature (1℃/min, 100s )	≤0.15	≤0.12	≤0.10	(°)/h
Zero bias repeatability	≤0.050	≤0.03	≤0.03	(°)/h
Random walk coefficient	≤0.002	≤0.002	≤0.001	(º)/h1/2
Scale factor nonlinearity	≤20			ppm
Scale factor asymmetry	≤20			ppm
Scale factor repeatability	≤20			ppm

Conclusion

With its high precision advantage, fiber optic gyroscopes have been widely used in fields such as aviation, navigation, and earthquake research. For example, in aircraft, fiber optic gyroscopes can accurately determine the position, velocity, and attitude of the aircraft, ensuring stable and precise flight direction. In summary, as a high-precision measurement device, the performance of fiber optic gyroscope is affected by various factors, but it still shows great potential and value in various fields of application.