Reflector arrangement with retroreflector and with a sensor arrangement for inclination determination and calibration

• US 10,054,439 B2
• Filed: 03/07/2015
• Issued: 08/21/2018
• Est. Priority Date: 03/07/2014
• Status: Active Grant

• Current Assignee: Hexagon Technology Center GmbH (Hexagon AB)
• Original Assignee: Hexagon Technology Center GmbH (Hexagon AB)
• Inventors: Jensen, Thomas, Siercks, Knut
• Primary Examiner(s): Ratcliffe, Luke D
• Application Number:
  US14/641,368
• Publication Number:
  US 20150253137A1
• Time in Patent Office: 1,263 Days
• CPC Class Codes: G01C 15/006 Detectors therefor
• CPC Class Codes: G01C 15/008 combined with inclination sensor
• CPC Class Codes: G01C 15/06 Surveyors' staffs; Movable markers
• CPC Class Codes: G01C 25/00 Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass testing, calibrating or compensating compasses G01C17/38
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver

Abstract

Reflector arrangement for position determination and/or marking of target points, in particular for industrial or geodetic surveying, having a retroreflector for position determination for the reflector arrangement using parallel, in particular coaxial, beam reflection, and a sensor arrangement. According to the invention, the sensor arrangement has a lens and a sensor which is sensitive with respect to at least one wavelength range, with a reception direction that is orthogonal to the detection surface thereof, wherein the lens and the sensor are rigidly connected such that it is possible using the sensor to determine a location, which is incidence-angle-dependent with respect to the reception direction, of an illumination cross section defined by the lens on the detection surface.

Claims

1. A reflector arrangement comprising:

a retroreflector for position determination for the reflector arrangement using parallel beam reflection; and

a sensor arrangement,

wherein the sensor arrangement includes;

a code element with a code pattern, and

a sensor which is sensitive with respect to at least one wavelength range, with a reception direction that is orthogonal to the detection surface thereof; and

wherein the code element and the sensor are rigidly connected, with a defined spacing, such that it is possible using the sensor to determine a location, which is angle-dependent with respect to the reception direction, of a projection of the code pattern onto the detection surface.

2. The reflector arrangement according to claim 1, wherein:

the reception direction of the sensor and an extension direction of the code element are aligned to be mutually orthogonal, and the defined spacing is at least 1 mm and at most 10 mm, wherein an extension direction of the sensor is aligned to be equal to the extension direction of the code element.

3. The reflector arrangement according to claim 1, wherein:

the code element has regions of different transmissivity at least with respect to optical radiation having a wavelength from the at least one wavelength range, wherein the code pattern is represented by the regions of different transmissivity, wherein the regions of different transmissivity define a line pattern having different line spacings and/or line widths.

4. The reflector arrangement according to claim 1, wherein:

the sensor comprises a sensor selected from the list consisting of a line sensor, an area sensor, a CCD, and a CMOS.

5. The reflector arrangement according to claim 1, wherein:

the reflector arrangement has a carrier structure, using which the target points can be positionally determined and/or marked, wherein the retroreflector and the sensor arrangement are carried by the carrier structure and are arranged in a known positional relation with respect to one another.

6. The reflector arrangement according to claim 5, wherein:

the carrier structure is configured as or has at least one of;

an auxiliary measuring instrument,

a mobile portable field controller with an optical targeting or marking unit for the position determination and/or marking of the target points, and

an add-on apparatus for securing the carrier structure on the auxiliary measuring instrument or the field controller.

7. The reflector arrangement according to claim 1, wherein:

the auxiliary measuring instrument comprises at least one of a surveying pole and a probing tool.

8. The reflector arrangement according to claim 1, wherein:

the reflector arrangement has at least one further sensor arrangement carried by the carrier structure, wherein the at least one further sensor arrangement is arranged in a defined alignment and a defined position in relation to the first sensor arrangement for determination of an inclination with respect to a further axis.

9. The reflector arrangement according to claim 1, wherein:

the reflector arrangement has a plurality of auxiliary point markings in a specified and known spatial distribution relative to one another, wherein the auxiliary point markings provide an inclination determination with respect to at least one further axis for the reflector arrangement by image processing of an image in which the auxiliary point markings are at least partially captured, wherein the auxiliary point markings provide a spatial orientation determination.

10. The reflector arrangement according to claim 9, wherein:

the auxiliary point markings comprise at least one of light-emitting diodes and reflectors.

11. The reflector arrangement according to claim 1, wherein:

the reflector arrangement has an inertial measuring unit for continuous determination of an orientation and/or inclination of the reflector arrangement for the determination of a change in at least one of position, orientation, and inclination, wherein the inertial measuring unit has an accelerometer, a rotation rate sensor, an inclination sensor and/or a magnetic compass.

12. The reflector arrangement according to claim 1, wherein:

the reflector arrangement has a transmitting unit for data transmission, wherein the transmitting unit is configured such that the data transmission can be carried out by way of emitting modulated electromagnetic radiation.

13. A calibration method having the reflector arrangement of claim 1, which is configured at least for position determination and/or marking of target points, having

the sensor arrangement which embodies a reference sensor arrangement, and

a first sensor unit,

wherein the reference sensor arrangement and the first sensor unit are arranged in known positional relation, with

generating of reference inclination data with respect to a first axis by way of the reference sensor arrangement;

and

calibrating of the first sensor unit with respect to the first axis on the basis of the reference inclination data,

wherein the generating of the reference inclination data includes;

receiving illumination radiation at an angle of incidence,

determining an illumination radiation incidence region, dependent on said angle of incidence, on a sensor of the reference sensor arrangement, and

deriving the reference inclination data from the location of the illumination radiation incidence region and a previously known incidence direction of the illumination radiation,

wherein the calibration of the first sensor unit takes place continuously at defined temporal intervals.

14. The calibration method according to claim 13, wherein:

the illumination radiation comprises collimated illumination radiation.

15. The calibration method according to claim 13, wherein:

the first sensor unit is used to generate first sensor data which represent the inclination with respect to the first axis,

a degree to which the first sensor data and the reference inclination data match is determined and

calibration of the first sensor unit is effected automatically in dependence on the degree of the matching.

16. The calibration method according to claim 13, wherein:

an inclination determination using the first sensor unit involves a changing measurement error, in particular which increases in the temporal progression, and

the measurement error is compensated for by calibrating the first sensor unit,

wherein the first sensor unit is configured as at least one of an inertial measuring unit (IMU) and as a multi-axis inclination sensor.

17. A method comprising:

providing the sensor arrangement of claim 1;

irradiating the retroreflector with measurement radiation and by positionally determining the reflector arrangement by way of the measurement radiation reflected by the retroreflector,

illuminating, in a collimated manner, the sensor arrangement, wherein an angle of incidence is defined by an alignment of the illumination axis in relation to the capturing direction of the sensor of the sensor arrangement,

position-sensitive capturing, with respect to the location on the detection surface of the sensor, of a beam incidence pattern produced during illumination of the illumination cross section or the projection of the code pattern on the sensor, and

deriving an inclination of the reflector arrangement with respect to at least the illumination axis from the location, which can be determined by way of the position-sensitive capturing, of the beam incidence pattern on the detection surface, wherein the location of the beam incidence pattern is dependent on the angle of incidence.

18. One or more non-transitory computer-readable media storing one or more programs that are configured, when executed, to cause one or more processors to execute the method recited in claim 13.