Precision Fiber-Optic Rotation Sensor
Official patent title
Compact fiber optic gyroscope with feedback-enhanced frequency interferometry for precision measurement
Arabic title: جيروسكوب مدمج من الألياف الضوئية بقياس تداخلي للتردد معزز بالتغذية الراجعة للقياس الدقيق
Invention
Invention
Problem
Conventional fiber-optic gyroscopes may struggle to resolve extremely slow angular motion because the Sagnac phase shift is very small. Modulation-heavy or complex closed-loop architectures can add processing error, cost, and reliability challenges.
Why it matters
Improved low-rate rotation sensing can support precision navigation, platform stabilization, robotics, autonomous systems, aerospace instrumentation, and other applications where drift and small angular changes matter.
Approach
Counter-propagating light in a fiber coil acquires a rotation-dependent phase shift, and a circulator-based feedback loop recirculates and optionally amplifies the recombined signal to accumulate the shift. Frequency-domain interferometry and FFT processing convert repeated spectral spacing into angular speed.
Who may benefit
Potential beneficiaries include inertial-navigation manufacturers, aerospace and defense suppliers, autonomous-vehicle and robotics developers, surveying and stabilization companies, and photonic-instrumentation laboratories.
Potential value
The architecture enhances small rotation-induced phase differences through optical feedback and reads them in the frequency domain, with claimed angular-speed resolution of about 0.1°/s and an optional interferometer for determining rotation direction.
Background
Background
Fiber-optic gyroscopes split light into clockwise and counterclockwise paths around a coil. Rotation creates a Sagnac phase difference that can be related to angular rate, allowing solid-state sensing without moving parts. At very low speeds, however, the phase shift approaches noise and resolution limits. Prior systems use modulation, pulsed sources, multiple coils, or complex closed-loop electronics, which may increase error and implementation complexity. The disclosed design repeatedly circulates the optical signal so that small phase differences accumulate before frequency-domain analysis.
Technology overview
Technology overview
A broadband SLED near 1550 nm feeds a 50/50 coupler, a three-port circulator, a second coupler, and an approximately two-kilometer optical-fiber coil. Clockwise and counterclockwise waves recombine after acquiring a Sagnac shift. The feedback path, optionally containing a gain-four optical amplifier, sends the signal through the coil again. An optical spectrum analyzer forms an interferogram, and a microprocessor applies an FFT and measures repeated-component spacing to calculate angular speed. A Mach–Zehnder interferometer can add a reference phase for direction sensing.
Potential applications
Potential applications
- Precision inertial navigation for aerospace and defense systems.
- Low-rate attitude sensing for autonomous vehicles and robots.
- Platform, antenna, and optical-instrument stabilization.
- Surveying and geophysical rotation measurement research.
- LiDAR and mobile-sensor orientation systems.
Evidence-supported advantages
Evidence-supported advantages
- Accumulates small Sagnac phase shifts through optical feedback.
- Uses frequency-domain interferometry and FFT-based readout.
- Provides an optional optical amplifier within the feedback path.
- Can determine rotation direction using an added reference phase.
- Claims angular-speed resolution of about 0.1°/s.
Development stage
Development stage
An optical architecture, feedback waveforms, interferograms, and signal-processing method are described; calibrated environmental performance, packaged-hardware reliability, and field navigation validation were not established. The development stage was not independently verified.
Commercial opportunity
Commercial opportunity
The design may support licensing or instrument co-development with inertial-sensor and photonics companies. Productization requires calibrated bias, noise, drift, dynamic-range, and temperature data, package miniaturization, vibration and shock testing, optical-component reliability, manufacturing tolerances, comparison with commercial gyroscopes, and field navigation trials.
Patent classifications
Patent classifications
WIPO IPC
- G01C19/72Measuring distances, levels or bearings; surveying; navigation; gyroscopic instruments; photogrammetry or videogrammetry
- G01C19/66Measuring distances, levels or bearings; surveying; navigation; gyroscopic instruments; photogrammetry or videogrammetry
CPC
- G01C19/72Measuring distances, levels or bearings; surveying; navigation; gyroscopic instruments; photogrammetry or videogrammetry
- G01C19/721Measuring distances, levels or bearings; surveying; navigation; gyroscopic instruments; photogrammetry or videogrammetry
- G01C19/668Measuring distances, levels or bearings; surveying; navigation; gyroscopic instruments; photogrammetry or videogrammetry
- G01C19/722Measuring distances, levels or bearings; surveying; navigation; gyroscopic instruments; photogrammetry or videogrammetry
- G01C19/64Measuring distances, levels or bearings; surveying; navigation; gyroscopic instruments; photogrammetry or videogrammetry
Inventors
Inventors
- First inventorMohamed Yehia Mohamed Shalaby
Keywords
Keywords
- fiber optic gyroscope
- Sagnac effect
- frequency interferometry
- optical feedback
- fiber circulator
- FFT
- angular speed
- inertial navigation
Patent document and drawings
Patent document and drawings
The patent publication is mapped to this record. Patent drawings remain within that publication; no separately cleared public media package has been supplied.