System and method for determining a pivot center and radius based on a least squares approach

• US 7,156,328 B2
• Filed: 12/22/2004
• Issued: 01/02/2007
• Est. Priority Date: 12/22/2004
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Samaha, Alain
• Primary Examiner(s): Scherbel; David A.
• Assistant Examiner(s): GORMAN, DARREN W
• Application Number:
  US11/021,335
• Publication Number:
  US 20060131450A1
• Time in Patent Office: 741 Days
• Field of Search: 239/728, 239/735, 239/739, 239/742, 239/722, 239/723, 239/726, 239/729, 239/743, 239/750, 701/213, 702/150, 342/357.06, 342/357.08
• US Class Current: 239/728
• CPC Class Codes: A01G 25/092 movable around a pivot centre

Abstract

A system and method for determining the center and radius based on a least squares approach is disclosed. In one embodiment, a farmer drives through a given arc of a circular field in question and periodically takes position measurements. In another embodiment, a Least-Squares Algorithm is used to estimate the best-fitting center and radius given the set of position measurements input by the farmer.

Claims

1. A method of determining the center point of rotation of a moveable dispenser, said dispenser having at least one path created by its wheels, comprising:

providing a position determination system mounted on a vehicle;

driving said vehicle along a portion of said path created by said dispenser movement;

collecting position data for said vehicle along said portion of the path;

processing said position data to determine the center of rotation of said moveable dispenser by a method of least squares.

2. The method of claim 1, wherein said moveable dispenser is one of an irrigation apparatus and a fumigation apparatus.

3. The method of claim 1, wherein providing the position determination system comprises mounting a positioning system on said vehicle, wherein said positioning system is selected from the group consisting of a Global Positioning System, GLONASS, Galileo and Global Navigation Satellite System.

4. The method of claim 1, wherein driving said vehicle comprises driving said vehicle along a portion of said path, where said portion is no greater than one-half of a length of said path.

5. The method of claim 1, wherein driving said vehicle comprises driving said vehicle along a portion of said path, where said portion is no greater than one-quarter of a length of said path.

6. The method of claim 1, wherein collecting position data comprises collecting a plurality of global position system coordinates for said vehicle during said driving along said portion of said path.

7. The method of claim 1, further comprising processing said position data to determine a radius of said path by said method of least squares.

8. The method of claim 1, wherein processing said position data comprises processing said position data to determine the center of rotation of said dispenser by a method of linearized least squares estimation.

9. The method of claim 8, further comprising transforming said position data to a two-dimensional coordinate system prior to said processing the position data.

10. The method of claim 1, wherein processing said position data comprises processing said position data to determine the center of rotation of said dispenser by a method of iterative least squares estimation.

11. The method of claim 10, wherein processing said position data comprises:

estimating an initial pivot center and an initial radius;

calculating a new pivot center and a new radius using said method of iterative least squares estimation;

comparing said initial pivot center to said new pivot center; and

determining if an error threshold has been met based on said comparing.

12. A system of determining the center point of rotation of a moveable dispenser comprising:

a dispenser having at least one path created by its wheels;

a position determination system mounted on a vehicle, wherein said vehicle is to move along a portion of said path created by said dispenser movement; and

,

a processor in communication with said position determination system, said processor to,

collect position data for said vehicle along said portion of the path, and

process said position data to determine the center of rotation of said moveable dispenser by a method of least squares.

13. The system of claim 12, wherein said moveable dispenser is one of an irrigation apparatus and a fumigation apparatus.

14. The system of claim 12, wherein said position determination system is selected from the group consisting of a Global Positioning System, GLONASS, Galileo and Global Navigation Satellite System a global positioning system.

15. The system of claim 12, wherein said portion of said path is no greater than one-half of a length of said path.

16. The system of claim 12, wherein said portion of said path is no greater than one-quarter of a length of said path.

17. The system of claim 12, wherein said position data comprises a plurality of global position system coordinates for said vehicle collected while said vehicle moves along said portion of said path.

18. The system of claim 12, wherein to process said position data to determine the center of rotation of said dispenser, said processor utilizes a method of linearized least squares estimation.

19. The system of claim 18, wherein said processor is further to transform said position data to a two-dimensional coordinate system prior to said processing the position data.

20. The system of claim 12, wherein to process said position data to determine the center of rotation of said dispenser, said processor utilizes a method of iterative least squares estimation.

21. The system of claim 20, wherein to process said position data, said processor is to,

estimate an initial pivot center and an initial radius,

calculate a new pivot center and a new radius using said method of iterative least squares estimation,

compare said initial pivot center to said new pivot center, and

determine if an error threshold has been met based on said comparing.

22. A system of determining the center point of rotation of a moveable dispenser comprising:

a dispenser having at least one path created by its wheels;

a position determination means coupled to a vehicle to collect position data for said vehicle while said vehicle moves along a portion of said path created by said dispenser movement; and

processing means to determine the center of rotation of said moveable dispenser using a method of least squares.

23. The system of claim 22, wherein said dispenser is one of an irrigation apparatus and a fumigation apparatus.

24. The system of claim 22, wherein said position data is data from one of a Global Positioning System, GLONASS, Galileo and Global Navigation Satellite System.

25. The system of claim 22, wherein said portion of said path is no greater than one-half of a length of said path.

26. The system of claim 22, wherein said portion of said path is no greater than one-quarter of a length of said path.

27. The system of claim 22, wherein said position data comprises a plurality of global position system coordinates for said vehicle collected while said vehicle moves along said portion of said path.

28. The system of claim 22, wherein said method of least squares is a method of linearized least squares estimation.

29. The system of claim 28, wherein said processing means further to transform said position data to a two-dimensional coordinate system prior to processing the position data.

30. The system of claim 22, wherein said method of least squares is a method of iterative least squares estimation.

31. The system of claim 30, wherein said processing means is further to,

estimate an initial pivot center and an initial radius,

calculate a new pivot center and a new radius using said method of iterative least squares estimation,

compare said initial pivot center to said new pivot center, and

determine if an error threshold has been met based on said comparing.