Portable base station network for local differential GNSS corrections

• US 8,803,735 B2
• Filed: 11/20/2011
• Issued: 08/12/2014
• Est. Priority Date: 11/19/2010
• Status: Active Grant

• Current Assignee: Agjunction LLC (Kubota Corporation)
• Original Assignee: Agjunction LLC (Kubota Corporation)
• Inventors: McClure, John A.
• Primary Examiner(s): Phan, Dao
• Application Number:
  US13/300,609
• Publication Number:
  US 20120127032A1
• Time in Patent Office: 996 Days
• Field of Search: 342/357.23, 342/357.24, 342/357.34, 342/357.44, 701/469, 701/470
• US Class Current: 342/357.44
• CPC Class Codes: G01S 19/071 DGPS corrections
• CPC Class Codes: G01S 19/13 Receivers

Abstract

A DGNSS-based guidance system, wherein a rover receiver first utilizes data from a master base station transceiver, a DGNSS reference network, or some other differential source to compute a differentially corrected location to establish a reference DGNSS relationship. Using this location and data observed only at the rover, the rover computes an internal set of differential corrections, which set is stored in computer memory, updated as necessary, and applied in future times to correct observations taken by the rover. As the rover enters into areas of other base station receiver reference networks, the rover transceiver will send positional information it receives from the master base station to the new, secondary base station. The secondary base station then calibrates its own reference information using information sent from the original master base station.

Claims

1. A method for differentially computing a rover unit location in a differential Global Navigation Satellite System (GNSS) with a computer system including a processor connected to an input and an output, the method comprising the steps of:

providing a master base station with a master base GNSS antenna, a master base GNSS receiver coupled to the base GNSS antenna and a master base communication system including a master base transmitter;

providing a secondary base station with a secondary base GNSS antenna, a secondary base GNSS receiver coupled to the secondary base GNSS antenna and a secondary base communication system including a secondary base transmitter;

providing a rover unit with a rover GNSS antenna, a rover GNSS receiver coupled to the rover GNSS antenna and a rover communication system connected to the computer system and including a rover receiver;

generating with the computer system a position offset corresponding to an offset between differential corrections created by said master base and said secondary base stations;

said rover transitioning from the coverage area of one said base station to the coverage area of the other said base station;

transmitting said position offset to said rover; and

correcting with the computer system said rover GNSS-defined positioning with said position offset.

2. The method of claim 1, which includes the additional steps of:

saving in each said base station multiple GNSS base locations;

determining a current GNSS location of a respective base receiver;

comparing said current GNSS base receiver location with multiple said saved GNSS base locations to retrieve a closest saved GNSS base location;

if a resultant distance between said current GNSS base receiver location and the closest saved GNSS base location, as determined by said comparing step, is less than a said threshold minimum distance, identifying as a base location the saved GNSS base location which is closest to said current GNSS base receiver location; and

otherwise identifying said current GNSS base receiver location as the base location and saving in said base station said current GNSS base receiver location.

3. The method according to claim 2, which includes the additional step of:

reusing said positional offset corresponding to said previous base location for transmission to said rovers.

4. The method according to claim 3, which includes the additional steps of:

marking field locations for said base stations;

removing said base stations from said marked field locations between uses; and

replacing said base stations at said marked field locations for subsequent uses.

5. The method of claim 1, which includes the additional step of:

manually entering said offsets in said base stations.

6. The method of claim 1, which includes the additional steps of:

automatically entering said offsets in said base stations.

7. The method of claim 1, which includes the additional steps of:

providing a network of overlapping base station coverage areas;

transitioning said rover among said base station coverage areas; and

applying a respective coverage area-specific offset to said rover as said rover transitions from one base station coverage area to another.

8. The method of claim 6, which includes the additional steps of:

averaging the offsets generated by said base stations;

applying said averaged offsets to said rover GNSS-defined position; and

determining with said rover a differentially-corrected GNSS-defined position using said averaged offsets.

9. The method of claim 1, which includes the additional steps of:

overlapping multiple said base station coverage areas within a network; and

minimizing GNSS position transitional errors among said base station coverage areas.

10. The method of claim 1, which includes the additional steps of:

receiving with said rover offsets from said master base station and said overlapping secondary base station; and

selecting an offset for use by said rover in an overlapping coverage area.

11. The method of claim 1, which includes the additional steps of:

moving said rover into a blocked-signal area whereat signals from a respective base station are blocked;

receiving signals from another base station in said blocked-signal area; and

utilizing the offset from said other base station for computing a rover GNSS-defined position in said blocked-signal area.

15. The method of claim 1, which includes the additional step of:

manually entering said offsets in said base stations.

16. The method of claim 1, which includes the additional steps of:

automatically entering said offsets in said base stations.

17. The method of claim 1, which includes the additional steps of:

providing a network of overlapping base station coverage areas;

transitioning said rover among said base station coverage areas; and

applying a respective coverage area-specific offset to said rover as said rover transitions from one base station coverage area to another.

18. The method of claim 1, which includes the additional steps of:

receiving with said rover offsets from said master base station and said overlapping secondary base station; and

selecting an offset for use by said rover in an overlapping coverage area.

19. The method of claim 1, which includes the additional steps of:

moving said rover into a blocked-signal area whereat signals from a respective base station are blocked;

receiving signals from another base station in said blocked-signal area; and

utilizing the offset from said other base station for computing a rover GNSS-defined position in said blocked-signal area.

12. A method for differentially computing with a computer system a rover unit location in a differential Global Navigation Satellite System (GNSS) comprising the steps of:

providing a master base station with a master base GNSS antenna, a master base GNSS receiver coupled to the base GNSS antenna and a master base communication system including a master base transmitter;

providing a secondary base station with a secondary base GNSS antenna, a secondary base GNSS receiver coupled to the secondary base GNSS antenna and a secondary base communication system including a secondary base transmitter;

providing a rover unit with the computer system, a rover GNSS antenna, a rover GNSS receiver coupled to the rover GNSS antenna and a rover communication system connected to the computer system and including a rover receiver;

generating with the computer system a position offset corresponding to an offset between differential corrections created by said master base and said secondary base stations;

said rover transitioning from the coverage area of one said base station to the coverage area of the other said base station;

transmitting said position offset to said rover;

correcting with the computer system said rover GNSS-defined positioning with said position offset;

saving with the computer system in each said base station multiple GNSS base locations;

determining with the computer system a current GNSS location of a respective base receiver;

comparing with the computer system said current GNSS base receiver location with multiple said saved GNSS base locations to retrieve a closest saved GNSS base location;

if a resultant distance between said current GNSS base receiver location and the closest saved GNSS base location, as determined by said comparing step, is less than a said threshold minimum distance, identifying with the computer system as a base location the saved GNSS base location which is closest to said current GNSS base receiver location; and

otherwise identifying with the computer system said current GNSS base receiver location as the base location and saving in said base station said current GNSS base receiver location.

13. The method according to claim 12, which includes the additional step of:

reusing said positional offset corresponding to said previous base location for transmission to said rovers.

14. The method according to claim 13, which includes the additional steps of:

marking field locations for said base stations;

removing said base stations from said marked field locations between uses; and

replacing said base stations at said marked field locations for subsequent uses.

20. A method for differentially computing with a computer system a rover unit location in a differential Global Navigation Satellite System (GNSS) comprising the steps of:

providing a master base station with a master base GNSS antenna, a master base GNSS receiver coupled to the base GNSS antenna and a master base communication system including a master base transmitter;

providing a secondary base station with a secondary base GNSS antenna, a secondary base GNSS receiver coupled to the secondary base GNSS antenna and a secondary base communication system including a secondary base transmitter;

providing a rover unit with a rover GNSS antenna, a rover GNSS receiver coupled to the rover GNSS antenna and a rover communication system including a rover receiver;

generating with the computer system a position offset corresponding to an offset between differential corrections created by said master base and said secondary base stations;

said rover transitioning from the coverage area of one said base station to the coverage area of the other said base station;

transmitting said position offset to said rover;

correcting with the computer system said rover GNSS-defined positioning with said position offset;

saving with the computer system in each said base station multiple GNSS base locations;

determining with the computer system a current GNSS location of a respective base receiver;

comparing with the computer system said current GNSS base receiver location with multiple said saved GNSS base locations to retrieve a closest saved GNSS base location;

if a resultant distance between said current GNSS base receiver location and the closest saved GNSS base location, as determined by said comparing step, is less than a said threshold minimum distance, identifying with the computer system as a base location the saved GNSS base location which is closest to said current GNSS base receiver location;

otherwise identifying with the computer system said current GNSS base receiver location as the base location and saving in said base station said current GNSS base receiver location;

reusing said positional offset corresponding to said previous base location for transmission to said rovers;

marking with the computer system field locations for said base stations;

removing said base stations from said marked field locations between uses;

replacing said base stations at said marked field locations for subsequent uses;

providing a network of overlapping base station coverage areas;

transitioning said rover among said base station coverage areas;

applying with the computer system a respective coverage area-specific offset to said rover as said rover transitions from one base station coverage area to another;

receiving with said rover offsets from said master base station and said overlapping secondary base station;

selecting with the computer system an offset for use by said rover in an overlapping coverage area;

moving said rover into a blocked-signal area whereat signals from a respective base station are blocked;

receiving signals from another base station in said blocked-signal area; and

utilizing with the computer system the offset from said other base station for computing a rover GNSS-defined position in said blocked-signal area.