Rotating head optical transmitter for position measurement system

• US 20020005944A1
• Filed: 09/10/2001
• Published: 01/17/2002
• Est. Priority Date: 10/13/1998
• Status: Active Grant

• Current Assignee: 7D Kinematic Metrology Inc.
• Original Assignee: Donald Todd, Scott C. Casteel, Thomas M. Hedges, Timothy Pratt
• Inventors: Todd, Donald, Casteel, Scott C., Pratt, Timothy, Hedges, Thomas M.
• Granted Patent: US 6,621,565 B2
• Time in Patent Office: Days
• US Class Current: 356/152.1
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: G01S 1/54 Narrow-beam systems producing at a receiver a pulse-type envelope signal of the carrier wave of the beam, the timing of which is dependent upon the angle between the direction of the receiver from the beacon and a reference direction from the beacon; Overlapping broad beam systems defining a narrow zone and producing at a receiver a pulse-type envelope signal of the carrier wave of the beam, the timing of which is dependent upon the angle between the direction of the receiver from the beacon and a reference direction from the beacon
• CPC Class Codes: G01S 1/7032 Transmitters
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves
• CPC Class Codes: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management

Abstract

An optical transmitter for use in position location or position measurement systems includes (i) an assembly including two optical sources that generate two optical beams which diverge in known ways in a first and second plane, respectively, and are narrow in the orthogonal planes, (ii) a power source which provides power to the assembly to rotate it at a constant angular velocity or with a previously known pattern of velocities through each complete rotation of the assembly, and (iii) a signaling unit that emits a synchronization signal at a specific rotational position of the assembly. The optical transmitter can be used in systems for determining points, lines, planes, distances, areas, volumes, azimuth, elevation, range, angles, or any other positional or spatial variable. The optical transmitter has wide application in, for example, surveying, construction, and the creation of virtual or real environments.

Claims

1. An optical transmitter for use with a position location system comprising:

a rotating head assembly including a first optical source that generates a first optical beam that is narrow in a first plane and diverges in a known way in an orthogonal plane which is orthogonal to the first plane;

a rotary power source for providing power to rotate the rotating head assembly at one or more known angular velocities; and

a signaling unit for emitting a synchronization signal at a specific rotational position of the rotating head assembly.

2. The optical transmitter of claim 1, further comprising a power transfer device that transfers power to the first optical source of the rotating head assembly.

3. The optical transmitter of claim 2, wherein the power transfer device comprises at least one of a rotary transformer, slip rings, a capacitive coupler, an inductive coupler, a radio frequency receiver, a light receiver, or a battery.

4. The optical transmitter of claim 1, wherein the first optical beam is collimated in the first plane.

5. The optical transmitter of claim 1, wherein the first optical source comprises a light emitting diode.

6. The optical transmitter of claim 1, wherein the first optical source comprises a laser.

7. The optical transmitter of claim 1, wherein the signaling unit comprises at least one of an optical source, a radio frequency source, or an electrical source.

8. The optical transmitter of claim 1, wherein the signaling unit emits the synchronization signal over at least one of a wire, an optical fiber, or free space.

9. The optical transmitter of claim 1, wherein the signaling unit comprises at least one light emitting diode that emits the synchronization signal.

10. The optical transmitter of claim 1, wherein the signaling unit emits the synchronization signal at an interval selected from the group consisting of once per revolution of the rotating head assembly, once per two revolutions of the rotating head assembly, and once per three revolutions of the rotating head assembly.

11. The optical transmitter of claim 1, wherein all the optical elements which are included in the optical transmitter, and upon which the first optical beam impinges, are spatially fixed with respect to each other.

12. The optical transmitter of claim 1, further comprising an optical-source control portion for controlling the amount of power to the first optical source.

13. The optical transmitter of claim 1, wherein the rotating head assembly includes a second optical source that generates a second optical beam.

14. The optical transmitter of claim 1, further comprising a signaling unit control portion which controls the signaling unit.

15. The optical transmitter of claim 1, further comprising a motor control portion, wherein the rotary power source includes an electrically actuated motor, and wherein the motor control portion controls the electrically actuated motor.

16. The optical transmitter of claim 2, wherein the rotating head assembly comprises the power transfer device.

17. The optical transmitter of claim 2, wherein

the power transfer device includes a stationary portion and a rotatable portion, and

the power transfer device transfers electrical power from the stationary portion to the rotatable portion.

18. The optical transmitter of claim 17, wherein the power transfer device includes a rotary transformer.

19. The optical transmitter of claim 13, wherein the second optical beam diverges in a second known way in a second plane and is narrow in a second orthogonal plane which is orthogonal to the second plane.

20. The optical transmitter of claim 13, wherein the first and second optical sources are offset by a separation angle of greater than sixty degrees with respect to an axis of rotation of the rotating head assembly.

21. The optical transmitter of claim 15, wherein the motor control portion controls the electrically actuated motor such that the rotating head assembly rotates with a constant angular velocity through each complete revolution of the rotating head assembly.

22. The optical transmitter of claim 15, wherein the motor control portion controls the electrically actuated motor such that the rotating head assembly rotates with known varying velocities through each complete revolution of the rotating head.

23. An optical transmitter for use with a position location system comprising:

a rotating head assembly including

a first optical source that generates a first optical beam that is narrow in a first narrow plane and diverges in a first known way in a first orthogonal plane which is orthogonal to the first narrow plane, and

a second optical source that generates a second optical beam that is narrow in a second narrow plane and diverges in a second known way in a second orthogonal plane which is orthogonal to the second narrow plane; and

a rotary power source for providing power to rotate the rotating head assembly at one or more known angular velocities.

24. The optical transmitter of claim 23, further comprising a power transfer device that transfers power to the first and second optical sources in the rotating head assembly.

25. The optical transmitter of claim 23, further comprising a signaling unit for emitting a synchronization signal at a specific rotational position of the rotating head assembly.

26. A method of transmitting an optical signal, the method comprising:

providing a rotating head assembly having a first optical source;

generating, with the first optical source, a first optical beam that is narrow in a first plane and diverges in a known way in an orthogonal plane which is orthogonal to the first plane;

rotating the rotating head assembly; and

emitting a synchronization signal at a specific rotational position of the rotating head assembly.

27. The method of claim 26, wherein the first optical beam is collimated in the first plane.

28. The method of claim 26, further comprising transferring electrical power from an electrical power source to the first optical source in the rotating head assembly.

29. The method of claim 26, further comprising:

providing a second optical source in the rotating head assembly; and

generating, with the second optical source, a second optical beam that is narrow in a second plane and diverges in a second known way in a second orthogonal plane which is orthogonal to the second plane.

30. The method of claim 26, wherein the second optical beam is collimated in the second plane.

31. The method of claim 26, wherein the orthogonal plane in which the first optical beam diverges has a tilt angle that is not equal to zero.

32. The method of claim 31, wherein the tilt angle is approximately thirty degrees.

33. The method of claim 28, wherein transferring electrical power includes transferring power from a stationary portion to a rotatable portion of a power transfer device.

34. The method of claim 29, wherein the first and second optical sources are offset by a separation angle of greater than sixty degrees with respect to the axis of rotation of the rotating head assembly.

35. The method of claim 29, wherein the orthogonal plane has a first tilt angle, the second orthogonal plane has a second tilt angle, and the first tilt angle is not equal to the second tilt angle.

36. A method of transmitting an optical signal, the method comprising:

providing a rotating head assembly having a first optical source and a second optical source;

generating, with the first optical source, a first optical beam that is narrow in a first plane and diverges in a first known way in an orthogonal plane which is orthogonal to the first plane;

generating, with the second optical source, a second optical beam that is narrow in a second plane and diverges in a second known way in a second orthogonal plane which is orthogonal to the second plane; and

rotating the rotating head assembly.

37. The method of claim 36, further comprising emitting a synchronization signal at a specific rotational position of the rotating head assembly.

38. An optical transmitter for use with a position location system comprising:

means for generating an optical beam that is narrow in a first plane and diverges in a known way in a second plane which is orthogonal to the first plane;

means for rotating the optical beam; and

means for emitting a synchronization signal at a specific rotational position of the optical beam.

39. The optical transmitter of claim 38, wherein

the means for generating the optical beam comprises an optical source,

the means for rotating the optical beam comprises a rotary power source that is adapted to rotate the optical source at one or more known angular velocities, and

the means for emitting a synchronization signal comprises a plurality of light emitting diodes.

40. The optical transmitter of claim 39, wherein the rotary power source rotates the optical source at a known pattern of velocities which varies with time.

41. An optical transmitter for use with a position location system comprising:

means for generating a first optical beam that is narrow in a first plane and diverges in a first known way in a second plane which is orthogonal to the first plane;

means for generating a second optical beam that is narrow in a third plane and diverges in a second known way in a fourth plane which is orthogonal to the third plane; and

means for rotating the first optical beam and the second optical beam, wherein the first and second optical beams are in a fixed spatial relationship.