METHOD AND APPARATUS FOR IN-FLIGHT CALIBRATION OF GYROSCOPE USING MAGNETOMETER REFERENCE

• US 20110167893A1
• Filed: 09/17/2008
• Published: 07/14/2011
• Est. Priority Date: 09/17/2008
• Status: Active Grant

• Current Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Original Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Inventors: Frey, Robert D. JR.
• Granted Patent: US 8,146,401 B2
• Time in Patent Office: Days
• US Class Current: 73/1.77
• CPC Class Codes: F41G 7/007 Preparatory measures taken before the launching of the guided missiles
• CPC Class Codes: G01C 21/1654 with electromagnetic compass
• CPC Class Codes: G01C 25/005 initial alignment, calibration or starting-up of inertial devices

Abstract

The system includes a mobile vessel having a body axis and a steering mechanism. A three-axis gyroscope is mounted within the vessel. A three-axis magnetometer is mounted within the vessel. A programmable device communicates with the three-axis gyroscope, the three-axis magnetometer, and the steering mechanism. The three-axis gyroscope may include three single axis gyroscopes.

Claims

1. A calibration system, comprising:

a mobile vessel having a body axis and a steering mechanism;

a three-axis gyroscope mounted within the vessel;

a three-axis magnetometer mounted within the vessel; and

a programmable device in communication with the three-axis gyroscope, the three-axis magnetometer, and the steering mechanism.

2. The calibration system of claim 1, wherein the three-axis gyroscope further comprises three single axis gyroscopes mounted independently within the mobile vessel.

3. The calibration system of claim 1, further comprising a seeker mounted within the vessel in communication with the programmable device.

4. The calibration system of claim 1, wherein each axis of the three-axis gyroscope is mounted substantially orthogonal relative to the other axes of the three-axis gyroscope.

5. The calibration system of claim 1, wherein each axis of the three-axis magnetometer is mounted at a known angle relative to the three-axis gyroscope.

6. The calibration system of claim 1, wherein the mobile vessel further comprises a projectile.

7. The calibration system of claim 1, wherein the programmable device is arranged to receive at least one output from the three-axis gyroscope and at least one output from the three-axis magnetometer and transmit at least one signal to the steering mechanism.

8. The calibration system of claim 1, further comprising a seeker mounted within the vessel in communication with the programmable device, the seeker mounted at a known orientation relative to the gyroscope.

9. The calibration system of claim 1, wherein the mobile vessel further comprises a water-based vehicle.

10. A method for calibration, the method comprising the steps of:

launching a mobile vessel having a body axis;

calibrating a three-axis gyroscope mounted within the mobile vessel using a three-axis magnetometer and a programmable device mounted within the vessel; and

altering a direction of the mobile vessel using a steering mechanism based on transformations calculated by the programmable device based on measurements by the gyroscope and a seeker.

11. The method of claim 10, furthering comprising orienting the three-axis magnetometer relative to the earth field.

12. The method of claim 10, further comprising launching the mobile vessel into the air.

13. The method of claim 10, further comprising calibrating the three-axis gyroscope only once during a flight of the mobile vessel.

14. The method of claim 10, further comprising calibrating the three-axis gyroscope repeatedly during a flight of the mobile vessel.

15. The method of claim 14, further comprising calibrating the three-axis gyroscope using an estimator.

16. The method of claim 10, wherein the step of calibrating further comprises calibrating the three-axis gyroscope in less than six seconds.

17. The method of claim 10, wherein the step of calibrating further comprises calibrating the three-axis gyroscope in less than two seconds.

18. The method of claim 10, further comprising altering a direction of the mobile vessel using a steering mechanism to generate data for calibrating at least one axis of the gyroscope.

19. A system of calibration, the system comprising:

means for launching a mobile vessel having a body axis;

means for calibrating a three-axis gyroscope mounted within the mobile vessel using a three-axis magnetometer and a programmable device mounted within the vessel; and

means for altering a direction of the mobile vessel using a steering mechanism based on transformations calculated by the programmable device based on measurements by the gyroscope and seeker.

20. The system of claim 19, further comprising means for calibrating the three-axis gyroscope in less than two seconds.