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US 6,320,664 B1Granted
Ruggedized structure for fiber optic gyroscope
AssigneeHoneywell Inc.
InventorsAndrew W. Kaliszek, Glen A. Sanders, Clarence E. Laskoskie
Life of this patent
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Abstract
A rectification error reducer for a fiber optic gyroscope, which is an intensity servo or compensator for reducing vibration effects in the optical signals caused by modulation at vibration frequencies induced by the gyroscope-operating environment. The vibration effects may be detected in signals from the photodiode output in amplitude form, which is used in a control system to null out optical intensity variations at the frequencies of vibration.
Claims53
A vibration suppressing structure for a fiber optic gyroscope, comprising:
- a first optical fiber arranged into a first plurality of concentric cylindrical layers, each of the concentric layers having a plurality of turns of said first optical fiber, and each of the turns arranged into a first predetermined winding pattern;
- a second optical fiber arranged into a second plurality of concentric cylindrical layers, each of the concentric layers having a plurality of turns arranged into a second predetermined winding pattern;
- and
- a support structure comprising:
- a spool for supporting the turns of said first optical fiber and the turns of said second optical fiber;
- and
- a circuit carrier attached to a first end of said spool, wherein said circuit carrier is attached to an integrated optical circuit, and wherein:
- said first and second optical fibers have optical fiber leads fastened to said circuit carrier;
- said integrated optical circuit has optical fiber leads fastened to said circuit carrier;
- each of the optical fiber leads of said integrated optical circuit is fastened with a portion of adhering material to said circuit carrier, such that each of the optical fiber leads of said integrated optical circuit is provided a first stiffness relative to said circuit carrier, and the first stiffness decreases with distance from said integrated optical circuit;
- and
- each of the optical fiber leads of said first and second optical fibers is fastened with a portion of adhering material to said support structure, such that each of the optical fiber leads of said first and second optical fibers is provided with a second stiffness relative to said support structure, and the second stiffness decreases with distance from said first and second fibers.
9 more elements
A vibration suppressing structure for a fiber optic gyroscope, comprising:
- a hub;
- an optical fiber sensing coil wound on said hub, and having first and second fiber end leads;
- an integrated optical circuit fastened to a first end of said hub, and having first and second fiber leads connected to the first and second leads of said optical fiber sensing coil, respectively;
- a shell enclosing said hub, sensing coil and integrated optical circuit, and fastened to said hub;
- and
- wherein:
- the first and second fiber end leads of said sensing coil, are fastened to said hub;
- the first and second fiber leads of said integrated optical circuit, are fastened to said hub;
- said shell is at least partially filled with a damping material to suppress relative movement between said hub, said integrated optical circuit and said shell.
6 more elements
A vibration suppressing structure for a fiber optic gyroscope, comprising:
- a support structure comprising:
- an at least partially hollow cylinder having first and second ends, walls and a longitudinal axis approximately parallel to and approximately equidistant from the walls of said cylinder;
- and
- an at least one approximately planar surface situated within said cylinder between the first and second ends, and approximately perpendicular to the longitudinal axis;
- an integrated optical circuit fastened to the planar surface;
- a sensing coil situated on said support structure;
- and
- a depolarizer coil situated on said support structure.
5 more elements
A fiber optic gyroscope comprising:
- a support structure;
- a sensing coil would on said support structure;
- an integrated optical circuit mounted on said support structure and connected to said sensing coil;
- a light source coupled to said integrated optical circuit;
- a light detector coupled to said integrated optical circuit;
- and
- an electronics circuit connected to said light detector and to said integrated optical circuit;
- wherein:
- said light source is configured to provide light to said integrated optical circuit which splits the light into two light beams that counter-propagate in said sensing coil;
- and
- vibration causes phase difference modulation of the two beams in said sensing coil at first and second harmonics of a frequency of a vibration;
- and
- wherein:
- said electronics circuit provides a closed-loop feedback to a phase modulator in said integrated optical circuit to reduce a phase difference between the two light beams in said sensing loop;
- and
- said electronics circuit has a bandwidth at a value sufficient to limit the first harmonic of the phase difference modulation to a predetermined value of magnitude.
13 more elements
A fiber optic gyroscope comprising:
- a light source;
- an integrated circuit comprising:
- a splitter coupled to said light source;
- and
- at least one modulator;
- a light detector coupled to said splitter;
- and
- an electronics circuit connected to said light detector and to said at least one modulator;
- and
- wherein:
- said light source is providing light to said splitter which splits the light into two light beams that counter-propagate in said sensing coil;
- vibration causes phase difference modulation of the two beams in said sensing coil at least one harmonic of a frequency of a vibration;
- said electronics circuit provides closed-loop feedback to said at least one modulator to reduce a phase difference between the two light beams that counter-propagate in said sensing loop;
- and
- said electronics circuit has a bandwidth at a value sufficient to limit the first harmonic of the phase difference modulation to a predetermined value of magnitude.
12 more elements
Dependencies are inferred from the claim text.