System for position and orientation determination of a point in space using scanning laser beams

• US 6,417,839 B1
• Filed: 05/20/1999
• Issued: 07/09/2002
• Est. Priority Date: 05/20/1999
• Status: Expired due to Term

• Current Assignee: Ascension Technology Corporation (Roper Technologies, Inc.)
• Original Assignee: Ascension Technology Corporation (Roper Technologies, Inc.)
• Inventors: Odell, Don
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): ZAMANI, ALI A
• Application Number:
  US09/315,148
• Time in Patent Office: 1,146 Days
• Field of Search: 345/158, 345/165, 345/154, 345/162, 345/167, 345/173, 345/207, 356/152, 356/375
• US Class Current: 345/158
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: G01S 3/781 Details
• CPC Class Codes: G01S 5/163 Determination of attitude using inertial means G01C9/00; control of attitude G05D1/49

Abstract

A system for position and orientation determination of a point in space employs, in a preferred embodiment, three scanning laser beams that rotate at a high rate of speed within a prescribed space. At least two of the beams are polarized and a sensor with two or three detectors is located within the prescribed space. In each embodiment, at least one of the detectors has an unobscured, clear view of all of the scanning light beams at all times and at least another of the sensors is partially obscured. In the preferred embodiments, at least one sensor is polarized as well. Computer means is provided to facilitate calculation of position and orientation of a point within the prescribed space.

Claims

1. A system for position and orientation measurement of a point in a prescribed space, comprising:

a) a source of light including three scanning, non-coplanar fan-shaped rotating light beams, each beam having known position and orientation at any particular time;

b) at least two of said light beams being uniquely polarized at angles of polarization different from one another;

c) a sensor device movable within said space and carrying sensor means for sensing said light beams;

d) said sensor means comprising three separate detectors including;

i) a first detector always exposed to light from said light beams;

ii) second and third detectors at least partially exposed to light from said light beams; and

iii) one of said three detectors being polarized at a particular angle of polarization; and

e) computer means for receiving signals from said detectors and, therefrom, measuring position and orientation of said point.

2. The system of claim 1, wherein said at least two of said light beams are polarized at 0°

and 45°

, respectively.

3. The system of claim 1, wherein said at least two of said light beams are polarized at0°

and 90°

, respectively.

4. The system of claim 1, wherein said at least two of said light beams are polarized at 45°

and 90°

, respectively.

5. The system of claim 1, wherein said at least two of said light beams are parallel.

6. The system of claim 1, wherein said at least two of said light beams are skewed with respect to one another at a skew angle.

7. The system of claim 6, wherein said skew angle is 60°

.

8. The system of claim 1, wherein said sensor device includes an apertured plate in front of said detectors.

9. The system of claim 1, wherein said first detector is unpolarized.

10. The system of claim 1, wherein said first detector is polarized.

11. The system of claim 10, wherein said first detector is polarized at a polarization angle of 90°

.

12. The system of claim 1, wherein said second detector is unpolarized.

13. The system of claim 1, wherein said second detector is polarized.

14. The system of claim 13, wherein said second detector is polarized at a polarization angle of 90°

.

15. The system of claim 1, wherein said third detector is unpolarized.

16. The system of claim 1, wherein said third detector is polarized.

17. The system of claim 1, wherein said third detector is polarized at a polarization angle of 45°

.

18. The system of claim 17, wherein said third detector is polarized at a polarization angle of 90°

.

19. The system of claim 17, wherein said sensor device includes an apertured plate in front of said detectors.

20. The system of claim 19, wherein said apertured plate has a polarizing filter therein overlying said third detector.

21. The system of claim 1, further including an auxiliary detector separate from said sensor device.

22. The system of claim 1, wherein said sensor device includes a first housing carrying said first and third detectors and a second housing carrying said second detector.

23. The system of claim 1, wherein each of said detectors includes a four quadrant position sensing detector.

24. The system of claim 23, wherein each of said detectors includes a focusing lens.

25. The system of claim 24, wherein said focusing lens is spherical.

26. The system of claim 1, wherein each of said detectors includes two orthogonally related single axis position sensing detectors.

27. The system of claim 26, wherein each single axis position sensing detector has a cylindrical focusing lens.

28. The system of claim 1, wherein each detector includes a cover plate having a plurality of parallel slots.

29. The system of claim 1, wherein a third one of said light beams is unpolarized.

30. The system of claim 1, wherein a third one of said light beams is circularly polarized.

31. The system of claim 2, wherein a third one of said light beams is polarized.

32. The system of claim 31, wherein said third one of said light beams is polarized at a polarization angle of 90°

.

33. The system of claim 1, wherein said first detector is located on said sensor device to facilitate measurement of position and light beam intensity for normalization.

34. The system of claim 33, wherein said second detector is located on said sensor device to facilitate measurement of roll and pitch.

35. The system of claim 34, wherein said third detector is located on said sensor device to facilitate measurement of yaw.

36. The system of claim 1, wherein said first detector is located on said sensor device to facilitate measurement of roll.

37. The system of claim 36, wherein said second detector is located on said sensor device to facilitate measurement of position and beam intensity.

38. The system of claim 37, wherein said third detector is located on said sensor device to facilitate measurement of position and beam intensity.

39. The system of claim 1, wherein said first detector is located on said sensor device to facilitate measurement of azimuth.

40. The system of claim 39, wherein said second detector is located on said sensor device to facilitate measurement of roll and azimuth.

41. The system of claim 40, wherein said third detector is located on said sensor device to facilitate measurement of roll.

42. The system of claim 1, wherein said second detector is located on said sensor device to facilitate measurement of elevation.

43. The system of claim 42, wherein said third detector is located on said sensor device to facilitate measurement of roll and azimuth.

44. The system of claim 1, wherein said source of light includes stationary light sources and a rotating mirror.

45. The system of claim 1, wherein said source of light includes rotating light sources.

46. A system for position and elevation measurement of a point in a prescribed space, comprising:

a) a source of light including three scanning, non-coplanar fan-shaped rotating light beams, each beam having known position and orientation at any particular time;

b) at least two of said light beams being uniquely polarized at angles of polarization different from one another;

c) a sensor device movable within said space and carrying sensor means for sensing said light beams;

d) said sensor means comprising two separate detectors including;

i) a first detector always exposed to light from said light beams; and

ii) a second detector at least partially exposed to light from said light beams and polarized at a particular angle of polarization; and

e) computer means for receiving signals from said detectors and, therefrom, measuring position and orientation of said point.

47. The system of claim 46, wherein said second detector is polarized at an angle of 90°

.

48. The system of claim 46, wherein said first detector is located on said sensor device to facilitate measurement of position.

49. The system of claim 48, wherein said second detector is located on said sensor device to facilitate measurement of elevation.

50. The system of claim 46, wherein said first detector is located on said sensor device to facilitate measurement of position and light beam intensity for normalization.

51. The system of claim 50, wherein said second detector is located on said sensor device to facilitate measurement of elevation and roll.

52. A system for position and orientation measurement of a point in a prescribed space, comprising:

a) a source of light including three scanning, non-coplanar fan-shaped rotating light beams, at least two of said beams having spaced sources and at least one of said beams being skewed with respect to an axis of rotation thereof, each beam having known position and orientation at any particular time;

b) at least one of said light beams being uniquely polarized at a particular angle of polarization and at least one other beam being either unpolarized or circularly polarized;

c) a sensor device movable within said space and carrying sensor means for sensing said light beams;

d) said sensor means comprising three separate detectors including;

i) a first detector always exposed to light from said light beams;

ii) second and third detectors at least partially exposed to light from said light beams; and

iii) two of said detectors being polarized at different angles of polarization; and

e) computer means for receiving signals from said detectors and, therefrom, measuring position and orientation of said point.

53. A system for position and at least one angle of orientation measurement of a point in a prescribed space, comprising:

a) a source of light including three scanning, non-coplanar fan-shaped beams, at least two beams having separated sources and at least one beam being skewed with respect to an axis of rotation thereof, each beam having known position and orientation at any particular time;

b) a sensor device movable in said space and carrying sensor means for sensing said light beams;

c) said sensor means comprising a position sensing detector; and

d) computer means for receiving signals from said position sensing detector and, therefrom, measuring position and orientation of said point, said computer means including means for measuring angle of incidence of said beams and, therefrom, measuring orientation of said sensor device.

54. The system of claim 53, wherein a focusing lens overlies said position sensing detector.

55. The system of claim 54, wherein said focusing lens is spherical.

56. The system of claim 53, wherein said sensor means includes two orthogonally related single axis position sensing detectors.

57. The system of claim 56, wherein each single axis position sensing detector has a cylindrical focusing lens.

58. The system of claim 53, wherein said sensor means has a cover plate including a plurality of slits.

59. The system of claim 53, wherein said position sensing detector is used to measure position, elevation and azimuth, and an auxiliary detector is added at a distance from the position sensing detector to measure position and using the positions of said position sensing detectors to calculate roll.

60. The system of claim 53, wherein the position sensing detector is used to measure position and azimuth and an auxiliary position sensing detector is added at a distance from the position sensing detector to measure elevation and position, and using the positions of the two position sensing detectors'"'"' position to calculate roll.