Digital Feedback Ramp Reset for Fiber Optic Gyroscope Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fiber-optic gyroscopes face challenges in maintaining sensitivity due to limited output range in electronics, leading to periodic resets that generate rate-dependent sinusoidal signals, which interfere with accurate rotation measurement.
Innovation Solution
A digital feedback system for fiber-optic gyroscopes that increments a feedback ramp signal based on rotation rate and resets it periodically based on time, rather than amplitude, to maintain a fixed frequency and variable amplitude, thereby avoiding frequency interference with rotation signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the feedback ramp signal is reset whenever a value that produces a 2π optical phase is reached, then the electronics stay within their operating range, but rate-dependent sinusoidal signals are generated in the gyroscope's frequency band-of-interest
Solution Approach 1:
The patent changes the reset parameter from amplitude-based (2π optical phase) to time-based (fixed frequency). The feedback ramp signal is reset after a predetermined number of increments at fixed frequency, regardless of amplitude. This parameter change eliminates rate-dependent sinusoidal errors while keeping electronics within operating range through variable amplitude control.
2Measurement precision
If the feedback ramp signal is reset periodically at fixed frequency, then rate-dependent sinusoidal errors are eliminated, but the electronics may exceed their output range
Solution Approach 1:
The patent makes the feedback ramp signal dynamic by allowing its amplitude to vary while maintaining a fixed reset frequency. The amplitude adjusts based on the rotation rate being measured, enabling the system to operate at the boundaries of electronics output range without exceeding them, while consistently eliminating rate-dependent sinusoidal errors through fixed-frequency resetting.
3Device complexity
If the feedback scheme uses amplitude-based resetting to maintain electronics operating range, then device complexity is reduced, but noise and scale factor errors increase
Solution Approach 1:
The patent implements periodic action by resetting the feedback ramp signal at a fixed frequency, creating a regular periodic pattern rather than irregular amplitude-based resets. This periodic resetting at optimized frequency reduces noise and scale factor errors while maintaining simple feedback control through systematic periodic operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces noise and scale factor errors, allowing for accurate rotation measurement while maintaining high sensitivity and avoiding rate-dependent sinusoidal errors in the critical frequency band.
Implementation Method 1
Fiber-optic gyroscopes measure angular rotation by determining the phase difference in light waves that propagate in opposite directions through a coil of optical fiber
Implementation Method 2
a phase modulator to modulate a phase of the first propagating light wave
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Digital feedback systems and methods for optical gyroscopes are provided. In one embodiment, a method for generating a closed loop feedback signal for a fiber optic gyroscope is provided. The method comprises demodulating a signal to determine a phase difference between two counter-propagating light waves; determining a rate of rotation based on the phase difference; incrementing a feedback ramp signal once every τ second period based on the rate of rotation; and resetting the feedback ramp signal when the ramp is incremented a predetermined number of times since a previous reset.