Method and system for relative tracking

• US 7,538,724 B1
• Filed: 06/15/2007
• Issued: 05/26/2009
• Est. Priority Date: 06/15/2007
• Status: Active Grant

• Current Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Original Assignee: ITT Manufacturing Enterprises, Inc. (ITT, Inc.)
• Inventors: Baillot, Yohan
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US11/763,763
• Time in Patent Office: 711 Days
• Field of Search: 34235706-35708, 342450-451, 342/457, 701/207, 701/213, 455/456.1, 455/456.3, 455/456.6
• US Class Current: 342/357.31
• CPC Class Codes: G01S 19/485 whereby the further system is an optical system or imaging system
• CPC Class Codes: G01S 19/53 Determining attitude
• CPC Class Codes: G01S 5/0294 Trajectory determination or predictive filtering, e.g. target tracking or Kalman filtering

Abstract

Systems and methods for providing relative tracking for a user in an unprepared environment, e.g., in the field. A larger mobile unit, such as a truck, is tracked precisely in world coordinates using GPS and/or other tracking technology. A smaller mobile object or unit is then tracked with respect to the larger mobile unit. The tracking information of the smaller mobile object or unit is then combined with the tracking of the larger mobile unit such that the tracking of the smaller mobile object or unit can be provided in world coordinates. The relative tracking methodology has particular utility in the field of augmented reality where precise tracking in an unprepared environment may be desirable, but where a smaller mobile object may not be able to be tracked directly and precisely in world coordinates.

Claims

1. A tracking method comprising:

establishing a position and orientation of a first mobile unit with respect to a world coordinate system, the first mobile unit being equipped with a first tracking system that is operable to produce tracking information in the world coordinate system;

tracking a position of a second mobile unit with respect to the first mobile unit using a second tracking system that is mounted on the first mobile unit and producing tracking information in a coordinate system relative to the first mobile unit, the second mobile unit being outside of any structural confines of the first mobile unit; and

combining the tracking information of the first mobile unit in the world coordinate system with the tracking information of the second mobile unit in the coordinate system relative to the first mobile unit to generate a position and orientation of the second mobile unit in the world coordinate system.

2. The method of claim 1, wherein the first mobile unit is a wheeled vehicle.

3. The method of claim 1, wherein the first mobile unit is a mobile rig.

4. The method of claim 1, wherein the first mobile unit is a water borne vessel.

5. The method of claim 1, wherein the second mobile unit comprises a head-mounted display.

6. The method of claim 5, further comprising updating images on the head-mounted display based on the position of the second mobile unit with respect to the world coordinate system.

7. The method of claim 1, wherein the step of establishing a position of the first mobile unit comprises receiving GPS signals.

8. The method of claim 1, wherein the second mobile unit comprises a camera.

9. The method of claim 1, wherein the step of tracking the position of the second mobile unit comprises pointing an optical short range tracker towards the second mobile unit.

10. The method of claim 1, wherein the position and orientation of the second mobile unit in the world coordinate system have a precision of, respectively, less than 0.1 meter and less than 1 degree.

11. The method of claim 1, further comprising using the position and orientation of the second mobile unit in the world coordinate system to generate computer-generated imagery for an augmented reality system.

12. The method of claim 1, wherein the second mobile unit does not itself generate tracking information.

13. A tracking method for use in an augmented reality system, the method comprising:

tracking a first mobile unit with respect to a world coordinate system, the first mobile unit being equipped with a first tracking system that is operable to produce tracking information in the world coordinate system;

tracking a second mobile unit with a tracking system mounted on the first mobile unit, the tracking of the second mobile unit being with respect to a position and orientation of the first mobile unit to produce tracking information of the second mobile unit, the second mobile unit being outside of any structural confines of the first mobile unit;

combining the tracking information of the first mobile unit in the world coordinate system with the tracking information of the second mobile unit, and thereby generate a position and orientation of the second mobile unit in the world coordinate system; and

displaying on a head-mounted display computer generated imagery that is associated with a real world scene and that is consistent with the position and orientation of the second mobile unit in the world coordinate system.

14. The method of claim 13, wherein the first mobile unit is a land vehicle.

15. The method of claim 13, wherein the first mobile unit is a water-borne vehicle.

16. The method of claim 13, wherein the second mobile unit comprises the head-mounted display.

17. The method of claim 13, wherein the step of tracking a first mobile unit comprises receiving GPS signals.

18. The method of claim 13, wherein the second mobile unit comprises a camera.

19. The method of claim 13, wherein the tracking system mounted on the first mobile unit comprises an optical short range tracker.

20. The method of claim 13, wherein the position and orientation of the second mobile unit in the world coordinate system have a precision of, respectively, less than 0.1 meter and less than 1 degree.

21. The method of claim 13, further comprising using the position and orientation of the second mobile unit in the world coordinate system to generate computer-generated imagery for an augmented reality system.

22. The method of claim 13, wherein the second mobile unit does not itself generate tracking information.

23. A system for tracking, comprising:

a first mobile unit comprising a first tracking system that is operable to produce tracking information for the first mobile unit in a world coordinate system, the first mobile unit further comprising a second tracking system that is operable to track an object with respect to the first mobile unit;

a second mobile unit configured to be tracked by the second tracking system at least when the second mobile unit is outside of any structural confines of the first mobile unit, the second tracking system configured to produce tracking information for the second mobile unit with respect to the first mobile unit; and

a coordinate combiner that receives (i) the tracking information for the first mobile unit in the world coordinate system and (ii) the tracking information for the second mobile unit with respect to the first mobile unit, and produces tracking information for the second mobile unit in the world coordinate system.

24. The system of claim 23, wherein the first mobile unit is a land-based vehicle.

25. The system of claim 23, wherein the first tracking system comprises a GPS receiver.

26. The system of claim 23, wherein the first tracking system comprises a plurality of GPS antennas arranged along a baseline.

27. The system of claim 23, wherein the second tracking system comprises an optical short range tracker.

28. The system of claim 23, wherein the second tracking system comprises at least one of an ultrasonic, a magnetic or a mechanical tracker.

29. The system of claim 23, wherein the second mobile unit comprises a part of an Augmented Reality system.

30. The system of claim 29, wherein the second mobile unit comprises a head-mounted display.

31. The system of claim 30, wherein the Augmented Reality system is configured to display on the head-mounted display computer generated imagery that is associated with a real world scene that is in a line of sight of a user and that is consistent with the tracking information of the second mobile unit in the world coordinate system.

32. The system of claim 23, wherein the second mobile unit does not itself generate tracking information.