Geodetic surveying system and method with multiple target tracking functionality

• US 10,240,924 B2
• Filed: 09/12/2012
• Issued: 03/26/2019
• Est. Priority Date: 09/13/2011
• Status: Active Grant

• Current Assignee: Hexagon Technology Center GmbH (Hexagon AB)
• Original Assignee: Hexagon Technology Center GmbH (Hexagon AB)
• Inventors: Metzler, Bernhard
• Primary Examiner(s): Suglo, Janet L
• Assistant Examiner(s): Liang, Leonard S
• Application Number:
  US14/344,590
• Publication Number:
  US 20140350886A1
• Time in Patent Office: 2,386 Days
• Field of Search: None
• CPC Class Codes: E02F 3/842 using electromagnetic, optical or photoelectric beams, e.g. laser beams
• CPC Class Codes: E02F 3/847 using electromagnetic, optical or acoustic beams to determine the blade position, e.g. laser beams
• CPC Class Codes: E02F 9/264 Sensors and their calibration for indicating the position of the work tool
• CPC Class Codes: G01C 15/00 Surveying instruments or accessories not provided for in groups G01C1/00 - G01C13/00
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: G01S 17/66 Tracking systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00

Abstract

A surveying system for surveying and tracking a movable target object that defines a target point includes a surveying device with a sighting unit defining a target axis and a detector for generating a continuously current amount-of-deviation signal dependent on a deviation from an optimal target orientation. A second unit on the target object side enables continuous determination of movements and/or positions of the target object with reference to an external coordinate system. The surveying system includes a target point tracking mode in which respective first measurement data currently generated by the first unit and the respective current amount-of-deviation signal and respective second measurement data currently generated by the second unit are continuously aggregated. On the basis thereof, a control signal is derived for continuous automatic motorized modification of the target axis orientation such that the target axis continuously aims at the target point.

Claims

1. A surveying system for surveying and tracking a movable target object that defines a target point, comprising:

a surveying device that constitutes a first unit, with position determining functionality for determining the position of the target point with reference to an internal coordinate system, wherein the surveying device includes;

a base;

a targeting device defining a target axis, wherein the alignment of the target axis is variable relative to the base in a motorized manner for precise sighting and tracking of the target point;

a photosensitive areal detector for continuously generating a current offset signal directly dependent on a direction and an extent of a deviation between a current, actual alignment of the target axis and a fictitious alignment of the target axis that is aimed highly precisely at the target point;

angle measuring functionality for continuously precisely detecting the current alignment of the target axis; and

distance measuring functionality for continuously determining the current distance to the target point;

a second unit, provided on the target object side, for providing a functionality for continuously determining movements and/or positions of the target object with reference to an external coordinate system, said functionality being independent of the position determining functionality of the first unit; and

a supervisory unit connected to the first and second units in terms of data and having evaluation, data processing and control functionality, wherein;

the surveying system has a target point tracking mode, in the context of which, in a manner automatically controlled by the supervisory unit in accordance with a predefined algorithm;

first measurement data continuously generated on the part of the first unit, said first measurement data being at least dependent on the current alignment of the target axis and the current offset signal, and

second measurement data continuously generated on the part of the second unit, said second measurement data being dependent on the currently detected movements and/or positions of the retroreflector,

are continuously aggregated and, on the basis thereof, a control signal is derived for continuously automatically changing the alignment of the target axis in a motorized manner in such a way that the target point is continuously sighted by means of the target axis,

wherein;

the first unit is configured to generate the first measurement data with a first rate;

the second unit is configured to generate the second measurement data with a second rate, wherein the second rate is higher than the first rate; and

in the context of the target point tracking mode, the predefined algorithm is clocked with a third rate, which is higher than the first rate and corresponds to the second rate.

2. The surveying system as claimed in claim 1, wherein:

the a first rate is in a range from approximately 1 to 20 Hz; and

the second rate is in a range from approximately 50 and 500 Hz.

3. The surveying system as claimed in claim 1, wherein:

in the context of the target point tracking mode, the control signal is derived with a fourth rate, which is higher than the first rate and corresponds to the third rate; and

the alignment of the target axis is continuously automatically changed in a motorized manner on the basis of the control signal.

4. The surveying system as claimed in claim 1, wherein:

in the context of the target point tracking mode, in a manner automatically controlled by the supervisory unit, the first and second measurement data are aggregated in each case across a specific preceding time period and, on the basis thereof, with the aid of the algorithm, a prediction is made with regard to a near-future position and/or movement of the target object and the control signal is additionally derived taking account of this prediction.

5. The surveying system as claimed in claim 1, wherein:

the second unit has an inertial measurement system having MEMS based acceleration sensors and rate of rotation sensors, in each case in three axes.

6. The surveying system as claimed in claim 1, wherein:

the second unit has a GNSS module having a GNSS antenna.

7. A surveying method for surveying and tracking a movable target object that defines a target point, using the first and second units as claimed in claim 1, comprising:

continuously generating first measurement data with the aid of the first unit, said first measurement data being at least dependent on the respectively current alignment of the target axis and the respectively current offset signal, wherein the first measurement data is generated with a first rate;

continuously generating second measurement data with the aid of the second unit, said second measurement data being dependent on the respectively currently detected movements and/or positions of the target object, wherein the second measurement data is generated with a second rate, wherein the second rate is higher than the first rate;

continuously aggregating the first and second measurement data using a predefined algorithm;

deriving, on the basis thereof, a control signal for continuously automatically changing the alignment of the target axis in a motorized manner in such a way that the target point is continuously sighted by means of the target axis; and

obtaining results from the use of the predefined algorithm that is clocked with a third rate, which is higher than the first rate and corresponds to the second rate.

8. The surveying method as claimed in claim 7, wherein:

the a first rate is in a range from approximately 1 to 20 Hz; and

the second rate is in a range from approximately 50 and 500 Hz.

9. The surveying method as claimed in claim 7, further comprising:

deriving the control signal with a fourth rate, which is higher than the first rate and corresponds to the third rate; and

continuously changing the alignment of the target axis in a motorized manner on the basis of the control signal.

10. The surveying method as claimed in claim 7, further comprising:

using the algorithm to accumulate the first and second measurement data, in each case across a specific preceding time period; and

on the basis thereof, determining a prediction with regard to a near future position and/or movement of the target object, the control signal being additionally derived taking account of said prediction.

11. A computer program product comprising program code, stored on a non-transitory machine readable carrier, for performing:

the process of continuously aggregating the first and second measurement data in accordance with the predefined algorithm, which is stored in the program code; and

the process of deriving, on the basis thereof, the control signal of the surveying method as claimed in claim 7.

12. The computer program product as claimed in claim 11, wherein:

the first unit is configured to generate the first measurement data with a first rate in a range from approximately 1 to 20 Hz;

the second unit is configured to generate the second measurement data with a second rate in a range from approximately 50 and 500 Hz, wherein the second rate is higher than the first rate;

in the context of the target point tracking mode, the predefined algorithm is clocked with a third rate, which is higher than the first rate and corresponds to the second rate;

in the context of the target point tracking mode, the control signal is derived with a fourth rate, which is higher than the first rate and corresponds to the third rate; and

the alignment of the target axis is continuously automatically changed in a motorized manner on the basis of the control signal.

13. The surveying system as claimed in claim 1, wherein:

the second unit is provided for fitting in a manner rigidly connected to the target object.

14. The surveying system as claimed in claim 1, wherein:

the surveying device has a laser that emits slightly divergent light beams in the direction of the target axis, for illuminating a retroreflector that constitutes the target object.

15. The surveying system as claimed in claim 1, wherein:

the first measurement data and the second measurement data are continuously aggregated using a Kalman filter.