System and method for creating accurate topographical maps using low-drift DGPS

• US 7,231,295 B2
• Filed: 04/07/2004
• Issued: 06/12/2007
• Est. Priority Date: 04/07/2004
• Status: Expired due to Fees

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Pickett, Terence D., Nelson, Frederick W., Hendrickson, Larry L.
• Primary Examiner(s): BEAULIEU, YONEL
• Application Number:
  US10/819,743
• Publication Number:
  US 20050228585A1
• Time in Patent Office: 1,161 Days
• Field of Search: 701/200, 701208-209, 701213-216, 340/988, 340/992, 342/357.06, 342/357.08, 404/83, 404/84.05, 404/84.1, 404/84.2, 404/84.8
• US Class Current: 701/208
• CPC Class Codes: G01C 15/00 Surveying instruments or accessories not provided for in groups G01C1/00 - G01C13/00

Abstract

The present invention is directed to a method for acquiring elevation data for an area. The method includes using a GPS receiver to map ground elevations while driving back and forth over an area and periodically recording position, elevation, and time. Then, at least one track is made across the parallel tracks so that the cross track intersects the parallel tracks. The data obtained is processed and elevation data from the cross track is used to adjust elevation data for the parallel tracks, compensating for elevation drift in measurements recorded by the GPS receiver. The adjusted data for the entire area is processed using the method of the present invention to obtain an elevation map for the area.

Claims

1. A method for acquiring elevation data for an area, comprising:

navigating a first track traversing the area generally along a first axis;

navigating a second track traversing the area, the second track being substantially parallel with the first track;

navigating a third track traversing the area generally along a second axis, the second axis intersecting the first axis;

periodically acquiring position, altitude and time data along the first, second and third tracks using a global positioning system (GPS); and

processing the acquired position, altitude and time data to obtain the elevation data for the area, wherein the position, altitude and time data for the third track are used to adjust the altitude data for the first and second tracks to account for elevation drift.

2. The method as claimed in claim 1, wherein the global positioning system (GPS) comprises a low drift wide area differentially corrected global positioning system (GPS).

3. The method as claimed in claim 1, further comprising using the elevation data to generate a topographical map of the area.

4. The method as claimed in claim 1, wherein the step of processing the acquired data further comprises:

determining a track segment along the first and second tracks having a drift rate, the track segment intersecting the third track at a first point and a second point, the first and second points being disposed on the first and second tracks;

calculating the elevations of the first point and the second point on the track segment using the acquired position, altitude and time data acquired for the third track; and

adjusting the elevation data along the track segment using the calculated elevation of the first and second points.

5. The method as claimed in claim 4, further comprising navigating at least a fourth track traversing the area, the fourth track being substantially parallel with the first track.

6. The method as claimed in claim 5, wherein the step of processing the acquired data further comprises:

determining at least a second track segment along two of the first, second, and fourth tracks having a drift rate, the second track segment intersecting the third track at a third point and a fourth point, respectively, the third and fourth points being disposed on any adjacent two of the first track, second track, and fourth track;

calculating the elevations of the third point and the fourth point on the second track segment using the acquired position, altitude and time data acquired for the third track; and

adjusting the elevation data along the second track segment using the calculated elevation of the third and fourth points.

7. The method as claimed in claim 1, further comprising locating the absolute altitude of a point in the area and using the absolute altitude of the point to adjust the elevation data to provide at least approximate absolute elevations for the area.

8. The method as claimed in claim 1, wherein the area comprises a field.

9. The method as claimed in claim 1, wherein the first track is generally perpendicular to the third track.

10. A system for acquiring elevation data for an area, comprising:

a global positioning system receiver for receiving a positioning signal from a global positioning system and generating position information for points within the area, the position information for each point including at least a position, an altitude and a time; and

a processing system for processing the position information to obtain elevation data for the area,

wherein the elevation data is obtained by navigating a first track traversing the area generally along a first axis;

navigating a second track traversing the area, the second track being substantially parallel with the first track;

navigating a third track traversing the area generally along a second axis, the second axis intersecting the first axis; and

periodically acquiring position, altitude and time data along the first, second and third tracks using the position information generated by the global positioning system receiver;

the position, altitude and time data for the third track are used to adjust the altitude data for the first and second tracks to account for elevation drift.

11. The system as claimed in claim 10, wherein the global positioning system (GPS) comprises a low drift wide area differentially corrected global positioning system (GPS).

12. The system as claimed in claim 10, further comprising a memory for recording the acquired position, altitude and time data.

13. The system as claimed in claim 10, wherein the elevation data is suitable for use in generating a topographical map of the area.

14. The system as claimed in claim 10, wherein the processing system processes the acquired position, altitude, and time data to obtain the elevation data by:

determining a track segment along the first and second tracks having a drift rate, the track segment intersecting the third track at a first point and a second point, the first and second points being disposed on the first and second tracks;

calculating the elevations of the first point and the second point on the track segment using the acquired position, altitude and time data acquired for the third track; and

adjusting the elevation data along the track segment using the calculated elevation of the first and second points.

15. The system as claimed in claim 14, wherein at least a fourth track traversing the area is navigated, the fourth track being substantially parallel with the first track.

16. The method as claimed in claim 15, wherein the processing system processes the acquired position, altitude and time data by:

determining at least a second track segment along two of the first, second, and fourth tracks having a drift rate, the second track segment intersecting the third track at a third point and a fourth point, respectively, the third and fourth points being disposed on any adjacent two of the first track, second track, and fourth track;

calculating the elevations of the third point and the fourth point on the second track segment using the acquired position, altitude and time data acquired for the third track; and

adjusting the elevation data along the second track segment using the calculated elevation of the third and fourth points.

17. The system as claimed in claim 10, wherein the processing system further locates the absolute position of a point in the area and using the absolute position of the point to adjust the elevation data to provide at least the approximate absolute elevation of the area.

18. The system as claimed in claim 10, wherein the area comprises a field.

19. The system as claimed in claim 10, wherein the first track is generally perpendicular to the third track.

20. A system for obtaining elevation data for an area, comprising:

means for navigating a first track at least substantially traversing the area generally along a first axis;

means for navigating a second track at least substantially traversing the area generally along a second axis, the second axis intersecting the first axis;

means for navigating a third track at least substantially traversing the area, the third track being substantially parallel with the second track;

means for periodically recording position, altitude and time data along the first, second and third tracks using a differentially corrected GPS; and

means for processing the recorded position, altitude and time data to obtain the elevation data for the area, wherein the position, altitude and time data for the first track and the position and time data for the second and third track are used to adjust the altitude data for the second and third tracks for elevation drift.