Method and apparatus for ground-based surveying in sites having one or more unstable zone(s)

• US 7,199,872 B2
• Filed: 05/18/2004
• Issued: 04/03/2007
• Est. Priority Date: 05/18/2004
• Status: Active Grant

• Current Assignee: Leica Geosystems AG (Hexagon AB)
• Original Assignee: Leica Geosystems AG (Hexagon AB)
• Inventors: Van Cranenbroeck, Joe
• Primary Examiner(s): Tarcza; Thomas H.
• Assistant Examiner(s): Ratcliffe; Luke D.
• Application Number:
  US10/847,445
• Publication Number:
  US 20070052951A1
• Time in Patent Office: 1,050 Days
• Field of Search: 356/139.03
• US Class Current: 356/139.03
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105

Abstract

The invention relates to ground-based surveying on a site (2) which comprises an unstable zone (60) and at least one control point (FCP1, FCP2, FCP6, FCP7; CP1–CP3) placed outside the unstable zone, in which method at least one surveying device (TS8, TS9; ST1–ST3) is used to acquire positional data by sighting least one control point (FCP1, FCP2, FCP6, FCP7; CP1–CP3). The approach comprises:

• • providing at least one sighting point (UP3–UP5; A–C) within the unstable zone (60; 20),
  • using the surveying device(s) (TS8, TS9; ST1–ST3) to acquire positional data by sighting the at least one sighting point (UP3–UP5; A–C) that is located within the unstable zone (60; 20), and
  • combining the positional data acquired from: i) the at least one control point (FCP1, FCP2, FCP6, FCP7; CP1–CP3) placed outside the unstable zone and ii) at least one sighting point (UP3–UP5; A–C) within the unstable zone (60; 20), to produce a positional reference for the surveying device(s).

The combining step can be implemented using a bundle adjustment technique.

Claims

1. Method of ground-based surveying on a site (2) which comprises an unstable zone (60;

20) and at least one control point (FCP1, FCP2, FCP6, FCP7;

CP1–

CP3) placed outside said unstable zone, in which method at least one surveying device (TS8, TS9;

ST1–

ST3) is used to acquire positional data by sighting at least one control point (FCP1, FCP2, FCP6, FCP7;

CP1–

CP3),

characterised in that it further comprises the steps of;

providing at least one sighting point (UP3–

UP5;

A–

C) within said unstable zone (60;

20),

using said surveying device(s) (TS8, TS9;

ST1–

ST3) to acquire positional data by sighting said at least one sighting point (UP3–

UP5;

A–

C) that is located within said unstable zone (60;

20), and

combining the positional data acquired from;

i) said at least one control point (FCP1, FCP2, FCP6, FCP7;

CP1–

CP3) placed outside said unstable zone and ii) at least one sighting point (UP3–

UP5;

A–

C) within said unstable zone (60;

20), to produce a positional reference for said surveying device(s).

2. Method according to claim 1, wherein more than one surveying device (TS8, TS9;

ST1–

ST3) is used, and wherein a plurality of surveying devices sight in common at least one common sighting point (UP3–

UP5;

A–

C) that is located in said unstable zone (60;

20), and wherein said positional data from the common sighting point(s) acquired by said surveying devices are used as positional data in said combining step.

3. Method according to claim 1, wherein said combining step comprises performing a bundle adjustment.

4. Method according to claim 1, wherein said combining step comprises performing a least squares adjustment on said positional data.

5. Method according to claim 1, wherein said positional reference is the coordinate system of said control point(s) (FCP1, FCP2, FCP6, FCP7;

CP1–

CP3) that are placed outside said unstable zone, said combining step converting the positional data of said sighting point(s) (UP3–

UP5;

A–

C) within said unstable zone (60;

20) into positional data of said coordinate system of said control point(s).

6. Method according to claim 1, wherein said surveying device(s) (TS8, TS9;

ST1–

ST3) is/are used without resorting to a physical alignment of its/their main axis with respect to the direction of gravity, said method comprising a step of computing rotational angles of the mechanical axis of said surveying device(s).

7. Method according to claim 1, wherein surveying device(s) (TS8, TS9;

ST1–

ST3) is/are used in a full three-dimensional reference frame.

8. Method according to claim 1, further comprising a step of associating a GPS (global positioning by satellite) device (22) with at least one sighting point (UP3–

UP5;

A–

C) within said unstable zone (60;

20) to acquire coordinate values thereof, and wherein said GPS coordinate values are exploited in said combining step.

9. Method according to claim 1, wherein:

said control point(s) have at least one known position coordinate ((X1, Y1), (X2, Y2), (X6, Y6), (X7, Y7)) in a first coordinate system (X,Y),

said at least one surveying device (TS8, TS9) is placed at a chosen location in said site to obtain at least one relative coordinate value of at least one said control point relative to the location of said surveying device,

said said at least one surveying device (TS8, TS9) is used at said chosen location to obtain relative coordinate data of said sighting point(s) (UP3–

UP5) within said unstable zone relative to the location of said surveying device, and

in said combining step, the position(s), in said first coordinate system (X,Y), of said sighting point(s) located in said unstable zone are determined on the basis of;

said relative coordinate(s) of said sighting point(s) located in said unstable zone relative to said chosen location(s),

said relative coordinate(s) of said control point(s) outside said unstable zone relative to said chosen location(s), and

said position coordinate(s) ((X1,Y1), (X2, Y2), (X6, Y6), (X7, Y7)) of said of said control point(s) outside said unstable zone in said first coordinate system.

10. Method according to claim 1, wherein the number of sighting control point(s) used is established to be equal to, or greater than, the minimum to keep a datum fixed, said minimum being number of points being available for the network of sighting points used in the surveyed site.

11. Method according to claim 1, wherein at least one sighting point (UP3–

UP5) within said unstable zone (60) is sighted from more than one chosen location of a said surveying device (TS8, TS9), thereby to acquire a respective relative position value of that sighting point (UP3–

UP5) from each said chosen location, and wherein said respective relative position values are used in said combining step.

12. Method according to claim 1, wherein at least one sighting point (UP3–

UP5) within said unstable zone (60) is sighted as a common sighting point by a plurality of surveying devices (TS8, TS9) at different locations of said site (2), and wherein position data indicating the position of that common sighting point (UP3–

UP5) relative to the position of each said plurality of surveying devices is used in said combining step.

13. Method according to claim 1, wherein said combining step implements a model adjusted by a least squares method.

14. Method according to claim 9, wherein said combining step implements a model adjusted by a least squares method that is used to provide:

coordinates for a said at least one sighting point (UP3—

UP3) located in said unstable zone (60), and

parameters of said surveying device (TS8, TS9) at said chosen location.

15. Method according to claim 1, wherein said combining step takes as position parameters only the coordinates of said at least one sighting point (UP3–

UP5) in a coordinate system of said surveying device (TS8, TS9).

16. Method according to claim 1, wherein more than one surveying device (TS8, TS9) is used on said site (2), whereby a plurality of surveying devices make sightings of a same sighting point (UP3–

UP3) and obtain position data of the latter within a common time frame.

17. Method according to claim 1, wherein a total station (TS8, TS9) is used as said surveying device.

18. Method according to claim 1, wherein said combining step is implemented with a coordinate transformation equation establishing a relationship between:

relative coordinate data of sighted points both within and outside said unstable zone (60), established on a relative coordinate system (x,y) of said at least one surveying device (TS8, TS9), and

a skew angle (a) between the set of axes of said first coordinate system (X,Y) and said relative coordinate system (x,y).

19. Method according to claim 18, wherein said relationship is established in determinant form.

20. Method according to claim 19, wherein said relationship comprises a first determinant containing relative coordinate data of at least one sighting point (UP3–

UP5) located in said unstable zone (60), determined from two or more surveying positions, operating as a multiplier on a column vector of numerical parameters of said surveying device(s) (TS8, TS9).

21. Application of the method according to claim 1 for establishing the position of at least one sighting point (UP3–

UP5) located in an unstable zone (60) in terms of a position on a coordinate grid system which also maps fixed control points (CP), whereby said at least one sighting point (UP3–

UP5) located in an unstable zone (60) becomes exploitable as a sighting control point.

22. Application of the method according to claim 1 for establishing the position of at least one sighting point (UP3–

UP5) located in the unstable zone (60) in terms of a position on a coordinate grid system to monitor evolutions in position of said at least one sighting point.

25. Executable code which, when run on a data processor, executes at least the combining step of claim 1.

26. Executable code according to claim 25, which, when run on a data processor, executes calculations in respect of a method of ground-based surveying on a site (2) which comprises an unstable zone (60;

20) and at least one control point (FCP1, FCP2, FCP6, FCP7;

CP1–

CP3) placed outside said unstable zone, in which method at least one surveying device (TS8, TS9;

ST1–

ST3) is used to acquire positional data by sighting least one control point (FCP1, FCP2, FCP6, FCP7;

CP1–

CP3),

characterised in that it further comprises the steps of;

providing at least one sighting point (UP3–

UP5;

A–

C) within said unstable zone (60;

20),

using said surveying device(s) (TS8, TS9;

ST1–

ST3) to acquire positional data by sighting said at least one sighting point (UP3–

UP5;

A–

C) that is located within said unstable zone (60;

20), and

combining the positional data acquired from;

i) said at least one control point (FCP1, FCP2, FCP6, FCP7;

CP1–

CP3) placed outside said unstable zone and ii) at least one sighting point (UP3–

UP5;

A–

C) within said unstable zone (60;

20), to produce a positional reference for said surveying device(s).

27. A data carrier storing the executable code of claim 25.

28. A processing apparatus loaded with the executable code of claim 25.

23. System for ground-based surveying on a site (2) which comprises an unstable zone (60;

20) and at least one control point (FCP1, FCP2, FCP6, FCP7;

CP1–

CP3) placed outside said unstable zone, comprising at least one surveying device (TS8, TS9;

ST1–

ST3) arranged to acquire positional data by sighting least one control point (FCP1, FCP2, FCP6, FCP7;

CP1–

CP3),

characterised in that it further comprises;

at least one sighting point (UP3–

UP5;

A–

C) within said unstable zone (60;

20), at least one said surveying device (TS8, TS9;

ST1–

ST3) being arranged to acquire positional data by sighting at least said sighting point within said unstable zone, and

means for combining the positional data acquired from;

i) said at least one control point (FCP1, FCP2, FCP6, FCP7;

CP1–

CP3) placed outside said unstable zone and ii) at least one sighting point (UP3–

UP5;

A–

C) within said unstable zone (60;

20), to produce a positional reference for said surveying device(s).

24. System according to claim 23, further configured to execute a method of ground-based surveying on a site (2) which comprises an unstable zone (60;

20) and at least one control point (FCP1, FCP2, FCP6, FCP7;

CP1–

CP3) placed outside said unstable zone, in which method at least one surveying device (TS8, TS9;

ST1–

ST3) is used to acquire positional data by sighting least one control point (FCP1, FCP2, FCP6, FCP7;

CP1–

CP3),

characterised in that it further comprises the steps of;

providing at least one sighting point (UP3–

UP5;

A–

C) within said unstable zone (60;

20),

using said surveying device(s) (TS8, TS9;

ST1–

ST3) to acquire positional data by sighting said at least one sighting point (UP3–

UP5;

A–

C) that is located within said unstable zone (60;

20), and

combining the positional data acquired from;

i) said at least one control point (FCP1, FCP2, FCP6, FCP7;

CP1–

CP3) placed outside said unstable zone and ii) at least one sighting point (UP3–

UP5;

A–

C) within said unstable zone (60;

20), to produce a positional reference for said surveying device(s), wherein more than one surveying device (TS8, TS9;

ST1–

ST3) is used, and wherein a plurality of surveying devices sight in common at least one common sighting point (UP3–

UP5;

A–

C) that is located in said unstable zone (60;

20), and wherein said positional data from the common sighting point(s) acquired by said surveying devices are used as positional data in said combining step.