Laser transmitter, laser receiver and method

• US 7,947,944 B2
• Filed: 11/03/2008
• Issued: 05/24/2011
• Est. Priority Date: 11/03/2008
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Talbot, Nicholas Charles
• Primary Examiner(s): Epps; Georgia Y
• Assistant Examiner(s): WILLIAMS, DON J
• Application Number:
  US12/263,772
• Publication Number:
  US 20100108858A1
• Time in Patent Office: 932 Days
• Field of Search: 250/205, 250/216, 250/221, 250/552, 250/553, 2502011-2014, 250/222.1, 250/237.R, 250/237.G, 372/50, 369/44.14, 369/112.14, 356/141, 356/152, 356/247, 356/248, 359/321, 359/576, 359/864
• US Class Current: 250/221
• CPC Class Codes: G01C 15/004 Reference lines, planes or sectors
• CPC Class Codes: G01C 15/006 Detectors therefor

Abstract

A combination of a laser transmitter and a laser receiver and a method determine the elevation of the receiver with respect to the transmitter. The laser transmitter includes a a laser light source for providing a beam of laser light and an element for directing the beam. The beam diverges vertically and varies in intensity vertically. A laser receiver includes an array of laser beam detectors for detecting the beam and the variations in the beam intensity in a vertical direction. The vertical position of the laser receiver with respect to the laser transmitter can be determined in this manner. The beam varies in intensity vertically in a predetermined vertical pattern, and the laser receiver detects at least a portion of the pattern defined by the beam such that the portion of the beam detected by the laser receiver may be determined.

Claims

1. In combination, a laser transmitter and a laser receiver for determining the elevation of the receiver with respect to the transmitter, comprising:

a laser transmitter including a laser light source for providing a beam of laser light and an element for directing the beam, said beam diverging vertically and varying in intensity vertically; and

a laser receiver including an array of laser beam detectors for detecting the beam and the variations in the beam intensity in a vertical direction such that the vertical position of the laser receiver with respect to said laser transmitter can be determined.

2. The laser transmitter and laser receiver for determining the elevation of the receiver with respect to the transmitter according to claim 1, in which said beam varies in intensity vertically in a predetermined vertical pattern, and in which said laser receiver detects at least a portion of the pattern defined by said beam such that the portion of the beam detected by the laser receiver may be determined.

3. The laser transmitter and laser receiver for determining the elevation of the receiver with respect to the transmitter according to claim 2, in which the pattern defined by the beam is cyclically varied such that ambiguities that might otherwise result as to the portion of the beam being detected by the laser receiver are eliminated.

4. The laser transmitter and laser receiver for determining the elevation of the receiver with respect to the transmitter according to claim 3, in which said transmitter transmits a beam in a succession of vertical patterns such that when said receiver detects a portion of the beam, any ambiguity with respect to which portion of the beam is detected is eliminated.

5. The laser transmitter and laser receiver for determining the elevation of the receiver with respect to the transmitter according to claim 4, in which said succession of vertical patterns constitutes a plurality of vertical patterns which are cyclically repeated.

6. The laser transmitter and laser receiver for determining the elevation of the receiver with respect to the transmitter according to claim 2, in which said pattern includes a reference section which permits the scale of the vertical dimensions of the pattern to be determined.

7. The laser transmitter and laser receiver for determining the elevation of the receiver with respect to the transmitter according to claim 6, in which the scale of said pattern in said reference section defines the scale of the vertical dimensions of the balance of the pattern.

8. The laser transmitter and laser receiver for determining the elevation of the receiver with respect to the transmitter according to claim 1, in which said transmitter provides a beam of laser light which is directed generally horizontally and which diverges vertically to define a vertical pattern of varying intensity that is readable by said laser receiver.

9. The laser transmitter and laser receiver for determining the elevation of the receiver with respect to the transmitter according to claim 8, in which said array of laser beam detectors detects the beam and the variations in the beam intensity in a vertical direction such that the vertical position of the laser receiver with respect to the horizontal portion of said laser beam is determined.

10. The laser transmitter and laser receiver for determining the elevation of the receiver with respect to the transmitter according to claim 1, in which the variations in beam intensity define a pattern having vertically spaced, generally horizontal bands of light and in which said pattern includes recognizable reference bands that define the size of the pattern, and in which a portion of the pattern is projected on a horizontal plane.

11. The laser transmitter and laser receiver for determining the elevation of the receiver with respect to the transmitter according to claim 10, in which said recognizable reference bands are vertically spaced in said pattern such that said receiver will receive at least one such band.

12. A method of determining the relative elevation of a laser receiver with respect to a laser transmitter, comprising the steps of:

projecting a beam of laser light with a laser transmitter in a generally horizontal path, said beam diverging vertically and varying in intensity vertically, and

detecting the beam of laser light at a plurality of vertically spaced points with a laser receiver including a vertical array of laser detectors such that the vertical position of the laser receiver with respect to the laser transmitter can be determined by determining the position of the laser receiver in the path of the beam of laser light.

13. The method of determining the relative elevation of a laser receiver with respect to a laser transmitter according to claim 12, in which the step of projecting a beam of laser light comprises the step of projecting a beam that has a predetermined vertical pattern, and in which the step of detecting the beam of laser light comprises the step of detecting at least a portion of the pattern defined by said beam such that the portion of the beam detected by the laser receiver may be determined.

14. The method of determining the relative elevation of a laser receiver with respect to a laser transmitter according to claim 13, in which the step of projecting a beam of laser light comprises the step of cyclically varying the pattern defined by the beam such that ambiguities that might otherwise result as to which portion of the beam is detected by the laser receiver are eliminated.

15. The method of determining the relative elevation of a laser receiver with respect to a laser transmitter according to claim 14, in which the pattern includes a reference section which permits the scale of the vertical dimensions of the patterns to be determined.

16. The method of determining the relative elevation of a laser receiver with respect to a laser transmitter according to claim 12, in which the step of projecting a beam of laser light comprises the step of projecting a succession of vertical patterns such that when said receiver detects a portion of the beam, any ambiguity with respect to which portion of the beam is detected is eliminated.

17. The method of determining the relative elevation of a laser receiver with respect to a laser transmitter according to claim 12, in which the step of projecting a beam of laser light comprises the step of projecting variations in the beam intensity to define a pattern having generally horizontal bands of light and in which said pattern includes recognizable reference bands that define the size of the pattern, and in which a portion of the pattern is projected on a horizontal plane.

18. The method of determining the relative elevation of a laser receiver with respect to a laser transmitter according to claim 17, in which said recognizable reference bands are vertically spaced in said pattern such that said receiver will receive at least one such band.

19. In combination, a laser transmitter and a laser receiver for determining the elevation of the receiver with respect to the transmitter, comprising:

a laser transmitter including a laser light source for providing a beam of laser light and an element for directing the beam such that it diverges vertically and varies in intensity vertically, said element including a micro mirror panel in which portions of the beam are reflected in a predetermined vertical pattern; and

a laser receiver including an array of laser beam detectors for detecting the beam and the variations in the beam intensity in a vertical direction such that the vertical position of the laser receiver with respect to said laser transmitter can be determined.

20. The laser transmitter and laser receiver for determining the elevation of the receiver with respect to the transmitter according to claim 19, in which said element includes a micro mirror panel arrange in a conical shape for reflecting portions of the beam in a predetermined vertical pattern.

21. The laser transmitter and laser receiver for determining the elevation of the receiver with respect to the transmitter according to claim 19, in which element includes a plurality of micro mirror panels arrange in a pyramid shape for reflecting portions of the beam in a predetermined vertical pattern.

22. The laser transmitter and laser receiver for determining the elevation of the receiver with respect to the transmitter according to claim 19, in which element includes

a flat micro mirror panel for reflecting portions of the beam received from said laser light source in a predetermined pattern, and

a conical reflector receiving light from said micro mirror panel and reflecting said portion of the beam generally outward in predetermined vertical pattern.

23. The laser transmitter and laser receiver for determining the elevation of the receiver with respect to the transmitter according to claim 22, in which said portions of the beam received from said laser light source are reflected from said flat micro mirror panel in a predetermined pattern of concentric rings of light and dark areas.