Distance measurement instrument with scanning function

• US 10,365,352 B2
• Filed: 06/02/2016
• Issued: 07/30/2019
• Est. Priority Date: 12/05/2013
• Status: Active Grant

• Current Assignee: Trimble AB (Trimble Inc.)
• Original Assignee: Trimble AB (Trimble Inc.)
• Inventors: Nordenfelt, Mikael, Hertzman, Mikael
• Primary Examiner(s): Ratcliffe, Luke D
• Application Number:
  US15/171,960
• Publication Number:
  US 20160274224A1
• Time in Patent Office: 1,153 Days
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G02B 26/108 having one or more prisms as scanning elements

Abstract

A measurement instrument is disclosed. The measurement instrument comprises a front lens assembly, a distance measurement module and a deflection module. The front lens assembly comprises an optical path along an instrument optical axis and the distance measurement module is configured to transmit and receive optical radiation along a measurement path. The deflection module is arranged between the distance measurement module and the front lens assembly to deflect the measurement path across the instrument optical axis.

Claims

1. A measurement instrument, comprising:

an alidade, a base, and a center unit, wherein the center unit is mounted on the alidade for rotation about a first axis and on the base for rotation about a second axis,

a first controllable drive for rotating the center unit about the first axis,

a second controllable drive for rotating the alidade about the second axis,

a front lens assembly having an optical path along an instrument optical axis,

a distance measurement module operative to transmit optical radiation from an optical transmission point along a transmit path and receive optical radiation at an optical reception point along a receive path,

a deflection module located optically between the distance measurement module and the front lens assembly and operative to deflect at least one of the transmit path or the receive path across the instrument optical axis so as to provide a scanning function, wherein the optical transmission point, the optical reception point, and the deflection module are located in the center unit, and

a synchronizer to synchronize operation of the first controllable drive, the second controllable drive, the deflection module, and the distance measurement module so as to obtain a grid of distance measurements having a selected angular spacing.

2. The instrument of claim 1, wherein the deflection module comprises at least one deflection element mounted for rotational motion and/or translational displacement such that at least one of the transmit path or the receive path is deflected with rotation and/or translational displacement of the deflection element.

3. The instrument of claim 2, further comprising a drive element operative to rotate and/or translate the at least one deflection element.

4. The instrument of claim 3, wherein the drive element is operative to produce at least one of an oscillating rotational motion of the at least one deflection element, a continuous rotational motion of the at least one deflection element, a directed rotational motion of the at least one deflection element to a selected orientation, or a translational displacement of the at least one deflection element.

5. The instrument of claim 3, wherein the drive element comprises at least one of a motor having constant rotational speed, a motor having a constant translational speed, a three-phase motor, a direct-current motor, or a piezoelectric element.

6. The instrument of claim 2, further comprising an angle sensor operative to detect an angle of rotation of the at least one deflection element and/or a displacement sensor operative to detect a translational displacement of the at least one deflection element.

7. The instrument of claim 3, further comprising a drive controller operative to control rotational motion and/or translational displacement of the at least one deflection element by the drive element.

8. The instrument of claim 7, wherein the drive controller is responsive to an angle sensor and/or a displacement sensor to control the drive element in dependence upon a rotation angle and/or a translational displacement of the at least one deflection element.

9. The instrument of claim 1, wherein the deflection module includes at least one deflection element comprising at least one of a prism, a multi-faceted mirror, or a disk having a scalloped curving mirrored surface.

10. The instrument of claim 2, further comprising a deflection lens assembly, wherein optical displacement due to the deflection element is converted to optical deflection, to produce angular deflection of the transmit path and/or the receive path across the instrument optical axis.

11. The instrument of claim 1, wherein the deflection module is operative to deflect at least one of the transmit path or the receive path in a deflection plane.

12. The instrument of claim 11, wherein the distance measurement module is operated at a controlled repetition rate to acquire a sequence of distance measurements, the deflection module is operated at a controlled deflection rate, or the deflection plane is oriented such that a sweep of the instrument optical axis at a given velocity about one of the first axis and the second axis enables acquisition of the sequence of distance measurements spaced apart in a two-dimensional polar grid.

13. The instrument of claim 1, wherein the deflection module is configured to displace either one of the transmit path or the receive path and wherein the front lens assembly is configured to convert a displacement of the transmit path or the receive path to an angular deflection across the instrument optical axis.

14. The instrument of claim 1, further comprising a mixer, wherein the deflection module is optically located between the distance measurement module and the mixer.