Two-level and two-period modulation for closed-loop interferometric fiber optic gyroscopes

Area of Science:

• Optoelectronics
• Inertial Navigation Systems
• Optical Metrology

Background:

• Interferometric fiber optic gyroscopes (IFOGs) are crucial for inertial navigation.
• Traditional modulation techniques face limitations in scale factor control, particularly at low angular velocities.
• Optimizing angle random walk (ARW) is essential for high-precision gyroscope applications.

Purpose of the Study:

• To propose and experimentally validate a novel modulation technique for closed-loop IFOGs.
• To improve scale factor control and reduce angle random walk in IFOGs.
• To offer a more efficient modulation scheme compared to existing methods.

Main Methods:

• A two-level, two-period modulation technique is proposed, utilizing intercalated square wave modulation periods.
• Angular velocity is derived from the difference between consecutive output levels.
• Modulation depth error is calculated from the mean output levels of consecutive periods.

Main Results:

• The proposed technique demonstrates improved scale factor control, overcoming limitations of standard square wave modulation at low angular velocities.
• Optimized angle random walk is achieved, leading to enhanced gyroscope performance.
• The method requires a slower analog-to-digital converter compared to four-level modulation schemes.

Conclusions:

• The novel modulation technique offers significant advantages for closed-loop interferometric fiber optic gyroscopes.
• It provides superior scale factor control and optimized angle random walk.
• This technique presents a practical advancement for high-performance gyroscope construction.