Field interchangable boresight mounting system and calibration method

• US 9,182,211 B2
• Filed: 12/04/2012
• Issued: 11/10/2015
• Est. Priority Date: 12/06/2011
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Jones, Ralph R., Weed, Douglas Mark, Storch, David Robert
• Primary Examiner(s): Williams, Hezron E
• Assistant Examiner(s): Nguyen, Hoang
• Application Number:
  US13/693,278
• Publication Number:
  US 20130139566A1
• Time in Patent Office: 1,071 Days
• Field of Search: 73/13.7, 73/13.8, 73/17.5, 73/17.7, 73/17.8, 702/92, 702150-153, 702/189, 333/13, 333/24
• US Class Current: 1/1
• CPC Class Codes: F41G 3/32 Devices for testing or checking
• CPC Class Codes: G01B 5/25 for testing the alignment of axes
• CPC Class Codes: G01C 25/005 initial alignment, calibration or starting-up of inertial devices

Abstract

A calibration method comprises providing a mounting fixture including a tray coupled to a frame, and an alignment measurement sensor removably coupled to the tray. An angular orientation of the tray is determined using the alignment measurement sensor removably coupled to the tray in a first position. The alignment measurement sensor is then moved to a second position on the tray that is rotated from the first position, and the angular orientation of the tray is determined using the alignment measurement sensor at the second position. An axis misalignment for at least two of a pitch axis, a roll axis, or a yaw axis of the alignment measurement sensor is then calculated to determine one or more misalignment factors. The one or more misalignment factors are then applied to correct for misalignment of the alignment measurement sensor.

Claims

1. A calibration method, comprising:

providing a mounting fixture including a tray coupled to a frame, and an alignment measurement sensor removably coupled to the tray;

determining a first reference position of the tray using the alignment measurement sensor removably coupled to the tray in a first position and orientation;

moving the alignment measurement sensor to a second position and orientation on the tray that is rotated from the first position and orientation;

determining a second reference position of the tray using the alignment measurement sensor at the second position and orientation;

calculating an axis misalignment for at least two of a pitch axis, a roll axis, or a yaw axis of the alignment measurement sensor to determine one or more misalignment factors, wherein the axis misalignment is calculated as;

axis misalignment=(axis@first position+axis@second position+relative angular offset error)/2;

where the axis@first position and the axis@second position include measured angles of the pitch axis, the roll axis, or the yaw axis; and

applying the one or more misalignment factors to correct for misalignment of the alignment measurement sensor.

2. The method of claim 1, further comprising:

moving the alignment measurement sensor back to the first position at least once from the second position;

determining an average of data measurements taken by the alignment measurement sensor and whether a current position of the alignment measurement sensor is within repeatability bounds;

if a resulting variation of the current position is within repeatability bounds, the average of the data measurements is used as the misalignment factor; and

if the resulting variation is outside of acceptable repeatability bounds, the measurements are rejected.

3. The method of claim 1, wherein the alignment measurement sensor comprises a boresighting device.

4. The method of claim 1, wherein each axis misalignment is calculated using a weighted value for each data measurement at a given position.

5. The method of claim 2, wherein if the current position is not within repeatability bounds, the method further comprising:

determining whether a predetermined number of iterations is exceeded;

if the predetermined number of iterations is not exceeded, moving the alignment measurement sensor to the second position; and

determining whether a then current position of the alignment measurement sensor is within repeatability bounds.

6. The method of claim 1, wherein the misalignment factors are applied to output angles of the alignment measurement sensor.

7. The method of claim 1, wherein the misalignment factors are applied to correct an alignment algorithm for the alignment measurement sensor by starting the alignment algorithm using the misalignment factors.

8. The method of claim 1, further comprising providing one or more angular offset measurement devices coupled to the tray.

9. The method of claim 1, wherein the mounting fixture further includes an adapter that removably couples the alignment measurement sensor to the tray.

10. The method of claim 9, further comprising providing one or more angular offset measurement devices mounted on the adapter.

11. The method of claim 1, further comprising providing a frame movement sensor affixed to the tray.

12. The method of claim 11, wherein the frame movement sensor comprises a boresighting device.

20. The method of claim 1, wherein the alignment measurement sensor at the second position and orientation is rotated about 180 degrees relative to the first position and orientation.

13. A boresight mounting system, comprising:

a mounting fixture comprising a tray having an outer surface and configured to be attached to a frame;

a frame movement sensor affixed to the outer surface of the tray;

an alignment measurement sensor removably coupled to the outer surface of the tray; and

a processor configured to execute instructions stored on a non-transitory processor readable medium to perform a calibration method comprising;

determining a first reference position of the tray attached to the frame based on data from the alignment measurement sensor in a first position and orientation;

determining a second reference position of the tray based on data from the alignment measurement sensor after being moved to a second position and orientation on the tray that is spaced apart and rotated from the first position and orientation;

calculating an axis misalignment for at least two of a pitch axis, a roll axis, or a yaw axis of the alignment measurement sensor to determine one or more misalignment factors, wherein the axis misalignment is calculated as;

axis misalignment=(axis@first position+axis@second position+relative angular offset error)/2;

where the axis@first position and the axis@second position include measured angles of the pitch axis, the roll axis, or the yaw axis; and

applying the one or more misalignment factors to correct for misalignment of the alignment measurement sensor.

14. The system of claim 13, further comprising one or more angular offset measurement devices coupled to the outer surface of the tray.

15. The system of claim 13, wherein the mounting fixture further comprises an adapter that removably couples the alignment measurement sensor to the tray.

16. The system of claim 15, further comprising one or more angular offset measurement devices mounted on the adapter.

17. The system of claim 13, wherein the frame movement sensor comprises a boresighting device.

18. The system of claim 13, wherein the alignment measurement sensor comprises a boresighting device.

19. A computer program product, comprising:

a non-transitory computer readable medium having instructions stored thereon executable by a processor to perform a calibration method, comprising;

determining a first reference position of a tray coupled to a frame based on data from a frame alignment measurement sensor removably coupled to the tray in a first position and orientation;

determining a second reference position of the tray based on data from the alignment measurement sensor after being moved to a second position and orientation on the tray that is spaced apart and rotated from the first position and orientation;

calculating an axis misalignment for at least two of a pitch axis, a roll axis, or a yaw axis of the alignment measurement sensor, wherein the axis misalignment is calculated as;

axis misalignment=(axis@first position+axis@second position+relative angular offset error)/2;

where the axis@first position and the axis@second position include measured angles of the pitch axis, the roll axis, or the yaw axis;

determining an average of data measurements taken by the alignment measurement sensor;

determining one or more misalignment factors from the average of the data measurements; and

applying the one or more misalignment factors to output angles of the alignment measurement sensor to correct for misalignment of the alignment measurement sensor.