Magnetic shield for a fiber optic gyroscope

• US 6,952,268 B2
• Filed: 08/21/2002
• Issued: 10/04/2005
• Est. Priority Date: 08/21/2002
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Vaught, Jesse Allen, McEwen, Matthew Brady, Williams, Wesley H., Olson, Matthew A.
• Primary Examiner(s): Toatley, Jr., Gregory J.
• Assistant Examiner(s): CONNOLLY, PATRICK J
• Application Number:
  US10/224,809
• Publication Number:
  US 20040036885A1
• Time in Patent Office: 1,140 Days
• Field of Search: 356/459, 356/460, 356/483, 356/465, 174/35.MS, 174/35.R
• US Class Current: 356/460
• CPC Class Codes: G01C 19/722 of the mechanical construction

Abstract

A magnetic shielding system for a fiber optic gyroscope is disclosed. The fiber optic gyroscope may have a sensing coil with a sensing axis. An exemplary magnetic shield may enclose the sensing coil and have a layer including a plurality of pieces connected at a seam. A portion of the seam may be substantially parallel to the sensing axis of the sensing coil. Also, the pieces may be connected together such that each piece has a portion of each of two sides and a wall of the magnetic shield. Additionally, multiple layers having orthogonal seams may be utilized with the magnetic shield.

Claims

1. A system for magnetically shielding exactly one fiber optic gyroscope, the system comprising:

exactly one fiber optic gyroscope having a sensing coil with a sensing axis; and

a magnetic shield including a plurality of layers each fabricated from a magnetic material and enclosing the exactly one fiber optic gyroscope;

wherein each of the layers includes a first piece and a second piece, the first piece and second piece are aligned and connected at a seam, and at least a portion of the seam has an angular separation of less than substantially 10 degrees from the sensing axis of the sensing coil.

2. The system of claim 1 wherein the magnetic material comprises a nickel-iron magnetic alloy.

3. The system of claim 1, wherein a flux path is continuous along each layer, and has an angular separation of less than substantially 10 degrees from the sensing axis.

4. The system of claim 1, wherein the magnetic shield and the sensing coil are attached to a support structure fabricated from a non-magnetic material.

19. The magnetic shield of claim 1, wherein the seam defines a plane, and the plane is substantially parallel to the sensing axis.

5. A magnetic shield for a single sensing coil with a sensing axis, the magnetic shield comprising:

a first layer and a second layer enclosing the single sensing coil;

wherein the first layer includes a first piece and a second piece connected by a first seam, and the second layer includes a third piece and a fourth piece connected by a second seam, a portion of the first seam is substantially parallel to the sensing axis, and a portion of the second seam is substantially perpendicular to the sensing axis.

6. The magnetic shield of claim 5 wherein the first layer and second layer comprise a high-permeability magnetic material.

7. The magnetic shield of claim 6, wherein the high-permeability magnetic material comprises a nickel-iron magnetic alloy.

8. The magnetic shield of claim 5, wherein the first seam and the second seam are orthogonal.

9. The magnetic shield of claim 5, wherein the first layer has a continuous flux path that is substantially parallel to the sensing axis, and the second layer has a continuous flux path that is substantially perpendicular to the sensing axis.

10. The magnetic shield of claim 5, wherein the first layer and second layer are attached to an intermediate support structure fabricated from a non-magnetic material.

11. The magnetic shield of claim 10, wherein the magnetic shield encloses only the sensing coil and the intermediate support structure.

12. The magnetic shield of claim 5 further comprising a third layer enclosing the fiber optic gyroscope.

13. A magnetic shield for a sensing coil, the magnetic shield comprising:

a plurality of layers enclosing the sensing coil, each layer having a first side and a second side connected by a wall;

wherein each of the plurality of layers includes a plurality of pieces, and each of the plurality of pieces includes a portion of each of the first side, the second side, and the wall.

14. The magnetic shield of claim 13 wherein the at least one layer comprises a high-permeability magnetic material.

15. The magnetic shield of claim 14, wherein the high-permeability magnetic material comprises a nickel-iron magnetic alloy.

16. The magnetic shield of claim 13 wherein at least one pair of the plurality of layers is attached to an intermediate support structure fabricated from a non-magnetic material.

17. The magnetic shield of claim 13, wherein the sensing coil is part of a single fiber optic gyroscope enclosed by the magnetic shield.

18. The magnetic shield of claim 13, wherein a flux path is continuous on each layer and substantially parallel to the sensing axis.

20. The magnetic shield of claim 13, wherein the magnetic shield comprises a thin-walled right circular cylinder with closed ends.

21. The magnetic shield of claim 13, wherein the magnetic shield encloses a second sensing coil having a second sensing axis, wherein the portion of the seam is substantially parallel to the second sensing axis.