SYSTEMS AND METHODS FOR GYROSCOPE CALIBRATION

• US 20110066395A1
• Filed: 09/14/2009
• Published: 03/17/2011
• Est. Priority Date: 09/14/2009
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Judd, Tom
• Granted Patent: US 8,548,766 B2
• Time in Patent Office: Days
• US Class Current: 702/104
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01C 25/00 Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass testing, calibrating or compensating compasses G01C17/38
• CPC Class Codes: G01C 25/005 initial alignment, calibration or starting-up of inertial devices

Abstract

Systems and methods may be used to determine gain compensation and/or bias compensation for gyroscopes in the field where access to specialized calibration tools is limited.

Claims

1. A method that compensates gyroscopes, the method comprising:

rotating a sensor platform with three gyroscopes, three accelerometers and three magnetometers thereon;

determining an observed rotation vector Og based upon the rotation sensed by at least one of the three gyroscopes;

determining a calculated rotation Om vector based upon the rotation sensed by the three accelerometers and the three magnetometers; and

determining a compensation gain and a compensation bias for the at least one gyroscope based upon the determined observed rotation vector and the determined calculated rotation vector.

2. The method of claim 1, wherein rotating the sensor platform comprises:

rotating the sensor platform about an out of plane axis.

3. The method of claim 1, wherein determining the observed rotation vector comprises:

calculating a first rotation based upon the rotation sensed by changes in the accelerometers (dA); and

calculating a second rotation based upon the rotation sensed by changes in the magnetometers (dM),

wherein an acceleration vector A associated with the accelerometers corresponds to the changes sensed by the accelerometers (dA), and

wherein a magnetic vector M associated with the magnetometers corresponds to the changes sensed by the magnetometers (dM), and

wherein the vector A and the vector M point in different directions.

4. The method of claim 3, wherein calculating the first rotation is based upon solving for changes in the acceleration vector A defined by:

dAx=Oz*Ay−

Oy*Az,

dAy=−

Oz*Ax+Ox*Az,

dAz=Oy*Az−

Ox*Ay, and

wherein determining the second rotation is based upon solving for changes in the magnetic vector M defined by;

dMx=Oz*My−

Oy*Mz,

dMy=−

Oz*Mx+Ox*Mz, and

dMz=Oy*Mz−

Ox*My.

5. The method of claim 4, wherein determining at least one of the compensation gain and the compensation bias for the gyroscope based upon the determined observed rotation vector the calculated rotation vector comprises:

selecting one of the first rotation and the second rotation; and

determining the observed rotation vector based upon a corresponding one of a first independent vector A and a second independent vector M.

6. The method of claim 5, wherein selecting one of the first independent vector A and the second independent vector M comprises:

determining a cross product of the first independent vector A with the second independent vector M;

determining which component of the cross product has the largest magnitude; and

selecting the equation combination according to which has the largest component in the denominator.

7. The method of claim 1, further comprising:

measuring the rotation with the gyroscope; and

measuring the rotation with the at least one the accelerometers and the magnetometers.

8. The method of claim 1, further comprising:

measuring the rotation with the three accelerometers orthogonally mounted on the sensor platform.

9. The method of claim 1, further comprising:

measuring the rotation with the three magnetometers orthogonally mounted on the sensor platform.

10. The method of claim 1, wherein determining at least one of the compensation gain and the compensation bias comprises:

determining at least one of a compensation gain and a compensation bias for three gyroscopes orthogonally mounted on the sensor platform based upon the determined observed rotation vector and the determined measured rotation vector.

11. The method of claim 1, wherein determining the observed rotation vector comprises:

determining a gravity vector.

12. A gyroscope calibration system, comprising:

three gyroscopes mounted on a sensor platform and configured to sense a rotation of the sensor platform;

three accelerometers and three magnetometers mounted on the sensor platform and configured to sense the rotation of the sensor platform; and

a processor system operable to receive information corresponding to the sensed rotation from the three gyroscopes and the at least one of the three accelerometers and the three magnetometers, and configured to;

determine a measured rotation vector based upon the rotation sensed by the gyroscopes;

determine an observed rotation vector based upon the rotation sensed by the at least one the three accelerometers and the three magnetometers; and

determine at least one of a compensation gain and a compensation bias for the at least one gyroscope based upon the determined observed rotation vector and the determined measured rotation vector.

13. The system of claim 12, wherein the three gyroscopes are orthogonally mounted on the sensor platform.

14. The system of claim 12, wherein the processor is configured to determine the observed rotation vector by:

calculating a first rotation based upon the rotation sensed by changes in the accelerometers (dA); and

calculating a second rotation based upon the rotation sensed by changes in the magnetometers (dM),

wherein an acceleration vector A associated with the accelerometers corresponds to the changes sensed by the accelerometers (dA), and

wherein a magnetic vector M associated with the magnetometers corresponds to the changes sensed by the magnetometers (dM), and

wherein the vector A and the vector M point in different directions.

15. The system of claim 12, wherein the processor system calculates the first rotation based upon solving for changes in the acceleration vector A defined by:

dAx=Oz*Ay−

Oy*Az,

dAy=−

Oz*Ax+Ox*Az,

dAz=Oy*Az−

Ox*Ay, and

wherein the processor system calculates the second rotation based upon solving for changes in the magnetic vector M defined by;

dMx=Oz*My−

Oy*Mz,

dMy=−

Oz*Mx+Ox*Mz, and

dMz=Oy*Mz−

Ox*My.

16. A system that compensates gyroscopes mounted on a sensor platform, comprising:

means for sensing a rotation of the sensor platform; and

means for determining a measured rotation vector based upon the rotation of the sensor platform sensed by three gyroscopes, determining an observed rotation vector based upon the rotation sensed by the means for sensing, and determining at least one of a compensation gain and a compensation bias for the gyroscopes based upon the determined observed rotation vector and the determined measured rotation vector.

17. The system of claim 16, wherein the means for sensing comprises at least one of three accelerometers and three magnetometers.

18. The system of claim 16, wherein the means for sensing comprises the three gyroscopes mounted on the sensor platform.

19. The system of claim 18, wherein the three gyroscopes are orthogonally mounted on the sensor platform.