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

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.

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.

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.

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.

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.

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.