Method and apparatus for in-flight calibration of gyroscope using magnetometer reference

• US 8,146,401 B2
• Filed: 09/17/2008
• Issued: 04/03/2012
• 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.
• Primary Examiner(s): Williams, Hezron E
• Assistant Examiner(s): Frank, Rodney T
• Application Number:
  US12/211,923
• Publication Number:
  US 20110167893A1
• Time in Patent Office: 1,294 Days
• Field of Search: 73/17.7, 735/033, 333/23
• 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, wherein the three-axis gyroscope receives a calibration reference signal from the magnetometer while the mobile vessel is in flight.

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.

11. 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.

12. 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.

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

6. A calibration system comprising,

a projectile having a body axis and a steering mechanism;

a three-axis gyroscope mounted within the projectile;

a three-axis magnetometer mounted within the projectile; and

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

7. The calibration system of claim 6, further comprising a seeker mounted within the projectile in communication with the programmable device.

8. The calibration system of claim 6, wherein each axis of the three-axis magnetometer is mounted at a known angle relative to the three-axis gyroscope.

9. The calibration system of claim 6, 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.

10. The calibration system of claim 6, further comprising a seeker mounted within the projectile in communication with the programmable device, the seeker mounted at a known orientation relative to the gyroscope.

14. 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 at least once during a flight of 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.

15. The method of claim 14, furthering comprising orienting the three-axis magnetometer relative to the earth field.

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

18. The method of claim 14, wherein the step of calibrating further comprises calibrating the three-axis gyroscope in less than six seconds.

19. The method of claim 14, wherein the step of calibrating further comprises calibrating the three-axis gyroscope in less than two seconds.

20. The method of claim 14, 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.

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

launching a mobile vessel having a body axis into the air;

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.