Technique for suppressing the electronic offset drift of interferometric open-loop fiber optic gyroscopes

Area of Science:

• Optical Engineering
• Instrumentation and Measurement
• Sensor Technology

Background:

• Offset drift in demodulator circuitry is a critical issue affecting the accuracy of open-loop interferometric fiber optic gyroscopes.
• Existing methods for drift compensation may not fully address the challenges posed by electronic offsets in high-precision applications.

Purpose of the Study:

• To present a novel technique for eliminating offset drift in the demodulator circuitry of fiber optic gyroscopes.
• To improve the angular velocity measurement accuracy and bias stability of these devices.

Main Methods:

• A demodulation scheme utilizing the area of negative half-cycles of the gyroscope's output signal to determine angular velocity.
• Implementation of electronic circuitry to periodically reverse the demodulator input, acquiring two oppositely polarized signal samples.
• Angular velocity calculation via subtraction of these samples to suppress electronic offset.

Main Results:

• The proposed method reduced demodulator offset drift from 4.4 μV/°C to approximately 14 nV/°C.
• This corresponds to a reduction in gyroscope angular velocity error from 0.2 deg/h/°C to about 0.0006 deg/h/°C.
• Bias stability of the tested gyroscope improved from 0.0162 deg/h to 0.0071 deg/h.

Conclusions:

• The presented technique effectively eliminates offset drift in fiber optic gyroscope demodulators.
• This method offers a significant improvement in angular velocity measurement precision and gyroscope bias stability.
• The findings are crucial for advancing high-accuracy inertial navigation systems.