FIBER OPTIC GYRO / THEORY & APPLICATIONS Yves PATUREL, MELAHA - - PowerPoint PPT Presentation
FIBER OPTIC GYRO / THEORY & APPLICATIONS Yves PATUREL, MELAHA Alexandria, September 2014 2 Contents Long term navigation key parameter FOG principle Key orders of magnitude Key features Comparison with other technologies
FIBER OPTIC GYRO / THEORY & APPLICATIONS
Yves PATUREL, MELAHA Alexandria, September 2014
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Contents
Long term navigation key parameter FOG principle Key orders of magnitude Key features Comparison with other technologies IXBLUE catalog examples
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Earth rotation vector module error
Composite bias : bias + effect of scale factor error on module Composite bias Earth Rotation
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Earth rotation vector module error
Composite bias : bias + effect of scale factor error on module Composite bias Earth Rotation
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Longitude error during a 60 hour navigation
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FOG - Sagnac effect
Digit ital al Signal l Process essing ing
COI Optical source
Opti ptical cal Coupler er
« All All-Digita tal » Proces essing Functi tion Modulation Module
Opti ptical cal Fiber er Coil
Optical detecto tor Detecti tion Module
Digit ital al Signal l Process essing ing
« All All-Digita tal » Proces essing Functi tion Modulation Module Optical detecto tor Detecti tion Module
NO ROTATION
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FOG - Sagnac effect
Digit ital al Signal l Process essing ing
COI Optical source
Opti ptical cal Coupler er
« All All-Digita tal » Proces essing Functi tion Modulation Module
Opti ptical cal Fiber er Coil
Optical detecto tor Detecti tion Module
Digit ital al Signal l Process essing ing
« All All-Digita tal » Proces essing Functi tion Modulation Module Optical detecto tor Detecti tion Module
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Response of the interferometer
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The « sensing sub-assembly »
One fundamental principle : reciprocity
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Single-axis fiber gyro
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Light source
980 980nm laser er FBG Er Er-do doped ped fiber er Isolat
980 0 nm nm 1550 50 nm nm
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Some interesting orders of magnitude
Best present results for fiber gyro : Wavelength : l = 1550 nm
Fiber length L few km few 109 l Bias stability : 0.001 deg/h over 28 deg/second (p phase shift) i.e. 10-8 of the wavelength
Relative detection of optical path length : few 10-18 ! With a relative variation of 7 x 10-6 / ºC for light velocity in the silica
fiber ! RECIPROCITY (perfect common-mode rejection)
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Actual configuration of a fiber gyro
Polarization-preserving fiber coil with typically 100 m to 10 km (manufactured by iXBlue). Proton-exchanged LiNbO3 integrated-optic circuit very high polarizer rejection (manufactured by
iXBlue).
Y-junction and pair of push-pull low-voltage phase modulators. Broad-spectrum source : unpolarized erbium ASE source for best performance (manufactured by
iXBlue).
All-digital processing electronics (invented by iXblue).
Fiber Coil Broadband Light Source Coupler Multi-function IOC Detector A / D Digital Logics D / A Rotation signal
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FOG comparison with other technologies
FOG has no lock-in zone
Always true in open-loop design.
In closed loop design, no dead zone in principle, but a “dead zone “ may appear if electronics design is not perfect (cross talk between modulation & detection chains)
In RLG (Ring Laser Gyro), lock-in is by-passed with dithering : this increases ARW, and provides acoustic noise
FOG has not (yet ?) reached a performance limit , while RLG faces a “non
reciprocity”
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FOG is easily scalable QUADRANS OCTANS AHRS PHINS INS MARINS INS IMU 50 IMU 90 IMU 120 IMU 200 Average Diameter (mm) 45 68 94 171 Bias Stability* (°/h) 0,05 0,025 0,01 0,001 Typical ARW (10-4 °/√h) 60 35 10 2
* Bias stability over the temperature range, -10 to +80°C à 1 σ
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FOG 50
IMU 50
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FOG 50 APPLICATIONS
Marine and Navy IMO gyrocompass Land survey, stabilization Military land navigation Airborne survey
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FOG 90
OCTANS ADVANS LANDINS
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FOG 90 APPLICATIONS
Navy & marine gyrocompass Land survey Military land navigation Artillery (qualified on 105 mm gun)
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FOG 120
PHINS ASTRIX 120 ADVANS
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FOG 120 APPLICATIONS
Navy & Marine navigation system Land military navigation Artillery (on 155 mm gun) Airborne survey
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FOG 200
MARINS ASTRIX 200
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FOG 200 APPLICATIONS
Submarine navigation and high-end surface vessels
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CONCLUSION
FOG technology is very reliable, very robust and has extremely long life time 44 FOG axes are on orbit around Earth cumulating more than 9300000
hours (106 years) without failure
FOG technology provides navigation for many marine applications :
Reliable and no maintenance gyrocompass,
Low power consumption inertial navigation system (especially suitable for AUV)
High performance navigation system for surface vessels and submarines
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