Rotating head optical transmitter for position measurement system

• US 6,621,565 B2
• Filed: 09/10/2001
• Issued: 09/16/2003
• Est. Priority Date: 10/13/1998
• Status: Expired due to Term

• Current Assignee: 7D Kinematic Metrology Inc.
• Original Assignee: Arc Second, Inc. (Nikon Corporation)
• Inventors: Todd, Donald, Casteel, Scott C., Pratt, Timothy, Hedges, Thomas M.
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US09/950,144
• Publication Number:
  US 20020005944A1
• Time in Patent Office: 736 Days
• Field of Search: 356/141.1, 356/141.4, 356/141.5, 356/152.1, 702/150-153, 359/180
• US Class Current: 356/141.4
• 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 in a position location system comprising:

a rotatable head assembly having a first optical source for generating a flat beam in a first plane that diverges in a second plane orthogonal to said first plane to generate a fan beam;

a power source for providing rotary power to said head assembly to drive said head assembly at one or more angular velocities;

a second optical source for generating a synchronizing pulse at a selected rotational position of said head assembly; and

means for controlling an energy distribution of said fan beam over a predetermined range of energy distributions.

2. The optical transmitter of claim 1, wherein said first optical source comprises at least two pairs of laser sources, and wherein a first pair of said laser sources generates fan beams having a first angle of divergence for long range system measurements and a second pair of laser sources generate fan beams having a second angle of divergence larger than the first angle of divergence for short range system measurements.

3. The optical transmitter of claim 1, wherein the second optical source comprises a plurality of light emitting devices which generate synchronizing pulse beams, wherein said first optical source generates a first fan beam having a first angle of divergence and a second fan beam having a second angle of divergence larger than the first angle of divergence such that the first fan beam is adapted for measurements in the vicinity of a horizontal plane through the transmitter and at a selected distance range from said transmitter, and wherein the second fan beam is adapted for measurements over a range of elevations in a volume surrounding said transmitter.

4. The optical transmitter of claim 3, wherein an energy distribution of at least one of said first and second fan beams is controllable by adjusting a tilt angle of said fan beam.

5. The optical transmitter of claim 4, wherein the energy distribution of at least one of said first and second fan beams is controllable by control means for controlling the amount of power applied to said first optical source.

6. The optical transmitter of claim 3, wherein said second angle of divergence is between one and ten degrees.

7. The optical transmitter of claim 3, wherein said first angle of divergence is between ten and ninety degrees.

8. The optical transmitter of claim 2, further comprising a switch for selectively activation at least one of said first and second pairs of laser sources to create at least one beam having a precisely controlled shape.

9. The optical transmitter of claim 1, wherein said means for controlling said energy distribution comprise means for controlling a divergence angle of said fan beam.

10. The optical transmitter of claim 9, wherein said predetermined range is a range of divergence angles of said fan beam from ten to ninety degrees.

11. The optical transmitter of claim 10, wherein said divergence angle is seventy degrees.

12. The optical transmitter of claim 1, wherein said means for controlling said energy distribution comprise means for controlling a title angle with respect to vertical of said fan beam.

13. An optical transmitter for use in a position measurement system comprising:

a rotatably supported head assembly including a first optical source that generates a first fan-shaped optical beam and a second optical source that generates a second fan-shaped optical beam;

a power source for providing rotary power to said head assembly to rotate said head assembly;

a third optical source for emitting a synchronizing beam at a selected rotational position of the head assembly; and

a plurality of auxiliary optical sources mounted on said head assembly for selectively operationally replacing at least one of said first, second, or third optical sources to control the energy distribution of said first fan shaped optical beam, the second fan-shaped optical beam, and the synchronizing beam, respectively.

14. The optical transmitter of claim 13, further comprising a switch for selectively activating one or more of said auxiliary optical sources to facilitate operation of said position measurement system in either a short range measurement mode or a long range measurement mode.

15. The optical transmitter of claim 13, further comprising a switch for selectively activating one or more of said first and second optical sources and said auxiliary optical sources to selectively create at least one beam having a precisely controlled shape.

16. A method for generating light beams in a three-dimensional position measurement system, comprising the steps of:

arranging a first optical source at a predetermined location on a rotatably mounted optical transmitter assembly to generate pairs of fan shaped beams;

providing a power source to impart rotary motion to said transmitter assembly at one or more predetermined angular velocities;

positioning a second optical source in a spaced position relative to said first optical source on said transmitter assembly for generating a periodic synchronization pulse beam as said transmitter assembly rotates; and

selectively controlling an energy level applied to at least one of said first and said second optical sources to facilitate short range or long range measurements.

17. The method of claim 16, wherein said selectively controlling step includes the step of controlling an angle of divergence of said light beams emitted by at least one of said first and said second optical sources.

18. The method of claim 17, wherein the angle of divergence for short range measurements controlled in said selectively controlling step is between ten to ninety degrees.

19. The method of claim 17, wherein the angle of divergence for long range measurements controlled in said selectively controlling step is between one to ten degrees.

20. In an optical transmitter for use in a position measurement system including a rotatable head assembly having a first optical source for generating a plurality of light beams for illuminating a measurement field, a power source for providing rotary power to rotate said head assembly at one or more predetermined angular velocities, and a second optical source for generating a synchronizing pulse at a selected rotational position of said head assembly, the improvement comprising:

a mounting means for fixing said first and said second optical sources to rotate with said head assembly, and

a controller for controlling an energy distribution pattern of at least one of said first or said second optical sources to provide energy distribution patterns having a first angle of divergence for long range system measurements and a second angle of divergence, larger than said first angle of divergence, for short range system measurements.

21. The improved optical transmitter of claim 20, wherein at least one of said first optical source and said second optical source comprises at least a pair of spaced light emitting optical device, wherein a first pair of said light emitting devices has a first angle of divergence for long range system measurements and a second pair of light emitting devices has a second angle of divergence, larger than said first angle of divergence, for short range system measurements.