Fiber-optic gyroscope (FOG) assembly

Patent metadata

Field	Value
Publication number	US-11079230-B2
Application number	US-201916409375-A
Country	US
Kind code	B2
Filing date	May 10, 2019
Priority date	May 10, 2019
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

One example includes a FOG assembly including a spool that includes a flattened portion corresponding to a flange comprising an axial center corresponding to a sensitive axis about which an associated FOG system is configured to measure rotation. The FOG assembly also includes a magnetic shield arranged as a capped concentric cover about the sensitive axis and coupled to the spool and the flange to create a toroidal cavity between the magnetic shield and the flange. A fiber coil is disposed within the toroidal cavity and coupled to the flange. The fiber coil includes an optical fiber which is counter-wound in first and second orientations. The fiber coil has an axial dimension along the sensitive axis that is less than or equal to approximately 160% of a radial width corresponding to a difference between an outer radius and an inner radius of the fiber coil.

First claim

What is claimed is:

1. A fiber optic gyroscope (FOG) assembly comprising:
a spool comprising a flange corresponding to a flattened portion comprising an axial center corresponding to a sensitive axis about which an associated FOG system is configured to measure rotation;
a magnetic shield arranged as a capped concentric cover about the sensitive axis and coupled to the flange to create a toroidal cavity between the magnetic shield and the flange; and
a fiber coil disposed within the toroidal cavity and coupled to the flange, the fiber coil comprising an optical fiber which is counter-wound in a first orientation and a second orientation opposite the first orientation, the fiber coil having an axial dimension along the sensitive axis that is less than or equal to approximately 160% of a radial width corresponding to a difference between an outer radius and an inner radius of the fiber coil.

2. The FOG assembly of claim 1 , wherein the axial dimension is less than or equal to approximately 0.5 inches, and the radial width is less than or equal to approximately 0.35 inches.

3. The FOG assembly of claim 1 , wherein the optical fiber has a cross-sectional diameter of between approximately 125 micrometers and approximately 135 micrometers.

4. The FOG assembly of claim 1 , wherein the FOG assembly further comprises a buffer material that is coupled to the flange and interconnects the fiber coil and the flange within the toroidal cavity.

5. The FOG assembly of claim 1 , wherein the fiber coil has a radial pitch of at most 150 micrometers between turns in a given layer of the optical fiber in the fiber coil, and has an axial pitch of at most 140 micrometers between layers of the optical fiber in the fiber coil.

6. The FOG assembly of claim 1 , wherein the optical fiber has a length of greater than or equal to approximately one kilometer, wherein the fiber coil has at least one of a number of layers of the optical fiber greater than or equal to fifty and a number of turns per layer of greater than or equal to eighty.

7. The FOG assembly of claim 1 , wherein the fiber coil comprises a top surface and a bottom surface opposite the top surface, the bottom surface being coupled to the flange, wherein a distance between the top surface and an opposing interior surface of the magnetic shield is at least 0.1 inches.

8. The FOG assembly of claim 1 , wherein the fiber coil has an optical fiber density of greater than or equal to approximately 28,000 optical fibers per square inch of cross-sectional area of the fiber coil.

9. An interferometric FOG comprising the FOG assembly of claim 1 , wherein the interferometric FOG further comprises an optical transceiver configured to provide an optical signal in the optical fiber to determine a rotation about the sensitive axis of the FOG assembly.

10. A method for manufacturing a fiber optic gyroscope (FOG) assembly, the method comprising:
counter-winding an optical fiber in each of a first orientation and a second orientation opposite the first orientation;
applying a potting material to the optical fiber to generate a fiber coil having a ring shape and comprising the optical fiber and the potting material, such that the fiber coil has an optical fiber density of greater than or equal to approximately 28,000 optical fibers per square inch of cross-sectional area of the fiber coil;
applying a buffer material on a flange corresponding to a flattened portion of a spool comprising an axial center corresponding to a sensitive axis about which an associated FOG system is configured to measure rotation; and
disposing the fiber coil within a toroidal cavity formed between the buffer material and the flange, and a magnetic shield arranged as a capped concentric cover about the sensitive axis and coupled to the flange.

11. The method of claim 10 , wherein applying the potting material comprises forming the fiber coil to have an axial dimension that is less than or equal to approximately 0.5 inches, and the radial width is less than or equal to approximately 0.35 inches.

12. The method of claim 10 , wherein the optical fiber has a cross-sectional diameter of between approximately 125 micrometers and approximately 135 micrometers.

13. The method of claim 10 , wherein counter-winding the optical fiber comprises counter-winding the optical fiber to have a radial pitch of at most 150 micrometers between turns in a given layer of the optical fiber in the fiber coil and to have an axial pitch of at most 140 micrometers between layers of the optical fiber in the fiber coil.

14. The method of claim 10 , wherein the optical fiber has a length of greater than or equal to approximately one kilometer, wherein counter-winding the optical fiber comprises counter-winding the optical fiber to have at least one of a number of layers of the optical fiber greater than or equal to fifty and a number of turns per layer of greater than or equal to eighty.

15. The method of claim 10 , wherein counter-winding the optical fiber comprises counter-winding the optical fiber to have a quadrupole wind pattern or an octopole wind pattern.

16. The method of claim 10 , wherein the fiber coil comprises a top surface and a bottom surface opposite the top surface, the bottom surface being coupled to the buffer material, wherein disposing the fiber coil in the toroidal cavity comprises disposing the fiber coil such that a distance between the top surface and an opposing interior surface of the magnetic shield is at least 0.1 inches.

17. An interferometric fiber optic gyroscope (FOG) comprising:
a FOG assembly comprising:
a spool comprising a flange corresponding to a flattened portion comprising an axial center corresponding to a sensitive axis about which the interferometric FOG is configured to measure rotation;
a magnetic shield arranged as a capped concentric cover about the sensitive axis and coupled to the spool and the flange to create a toroidal cavity between the magnetic shield and the flange;
a buffer material that is coupled to the flange within the toroidal cavity; and
a fiber coil disposed within the toroidal cavity and coupled to the buffer material, the fiber coil comprising an optical fiber having a length that is greater than approximately 1 kilometer and which is counter-wound in a first orientation and a second orientation opposite the first orientation, the fiber coil having an axial dimension along the sensitive axis that is less than or equal to approximately 0.5 inches and a radial width corresponding to a difference between an outer radius and an inner radius of the fiber coil that is less than or equal to approximately 0.35 inches; and

an optical signal in the optical fiber to determine a rotation about the sensitive axis of the FOG assembly.

18. The interferometric FOG of claim 17 , wherein the optical fiber has a cross-sectional diameter of between approximately 125 micrometers and approximately 135 micrometers.

19. The interferometric FOG of claim 17 , wherein the optical fiber has a radial pitch of at most 150 micrometers between turns in a given layer of the optical fiber in the fiber coil, and has an axial pitch of at most 140 micrometers between layers of the optical fiber in the fiber coil.

20. The interferometric FOG of claim 17 , wherein the fiber coil comprises a top surface and a bottom surface opposite the top surface, the bottom surface being coupled to the flange, wherein a distance between the top surface and an opposing interior surface of the magnetic shield is at least 0.1 inches.

Assignees

• Kim Steven M
• Zimmerman Gregory A
• Tazartes Daniel A
• Bateman Brent Robert
• Northrop Grumman Systems Corp

Inventors

• Kim Steven M
• Zimmerman Gregory A
• Tazartes Daniel A
• Bateman Brent Robert

Classifications

• G01C19/722 Primary

  of the mechanical construction · CPC title