GNSS moving base positioning

• US 8,400,351 B2
• Filed: 02/20/2010
• Issued: 03/19/2013
• Est. Priority Date: 02/22/2009
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Talbot, Nicholas Charles, Vollath, Ulrich
• Primary Examiner(s): Keith, Jack W
• Assistant Examiner(s): Mull, Fred H
• Application Number:
  US12/660,091
• Publication Number:
  US 20100214161A1
• Time in Patent Office: 1,123 Days
• Field of Search: 342/357.26, 342/357.27, 701/477
• US Class Current: 342/357.27
• CPC Class Codes: G01S 19/44 Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method

Abstract

Methods and apparatus are presented for determining a position of an antenna of a GNSS rover from observations of GNSS signals collected at the antenna over multiple epochs and from correction data for at least one of the epochs. A first-epoch rover position relative to a moving base location is determined, a second-epoch update of the first-epoch rover position relative to the moving base location for a second epoch is determined using a single-differenced delta phase process, and the first-epoch position and the second-epoch update are combined to obtain a second-epoch rover position relative to a moving base location of the second epoch.

Claims

1. A method of determining a position of an antenna of a GNSS rover from observations of GNSS signals collected at the antenna over multiple epochs and from correction data for at least one of the epochs, comprising:

determining a first-epoch rover position relative to a first-epoch moving base location,

determining a second-epoch update of the first-epoch rover position relative to a second-epoch moving base location using a single-differenced delta phase process,

combining the first-epoch rover position and the second-epoch update to obtain a second-epoch rover position relative to the second-epoch moving base location, and

for each of a plurality of subsequent epochs, determining a subsequent-epoch update and using the subsequent-epoch update to obtain a subsequent-epoch rover position relative to a moving base location of the subsequent epoch,

wherein determining a first-epoch rover position relative to a moving base location is repeated at a first rate, and wherein determining a subsequent-epoch update is repeated at a second rate which is higher than the first rate.

2. The method of claim 1, wherein for each epoch the rover position relative to the moving base location represents a vector defining a heading.

3. The method of claim 1, wherein the antenna of the GNSS rover and an antenna of a GNSS moving-base station are affixed to a movable object, such that at each epoch the rover position relative to the moving base location represents a vector defining an orientation of the movable object.

4. The method of claim 1, further comprising determining the first-epoch moving base location relative to a fixed-base location, using fixed-base correction data which comprises at least one of:

correction data prepared from observations of a physical base station, correction data prepared from observations of a network of reference stations, correction data prepared from observations of a global network of reference stations, and correction data prepared from observations of a regional network of reference stations.

5. The method of claim 4, wherein determining the moving base location is based on one of (i) fixed carrier-phase ambiguities and (ii) a weighted average of carrier-phase ambiguity candidates which is converged to a predetermined threshold.

6. The method of claim 1, wherein for each epoch a rover position relative to a moving base location is determined which defines a vector defining a heading for such epoch.

7. A computer program product comprising:

a non-transitory computer usable medium having computer readable instructions physically embodied therein, the computer readable instructions when executed by a processor enabling the processor to perform the method of claim 1.

8. Apparatus for determining a position of an antenna of a GNSS rover from observations of GNSS signals collected at the antenna over multiple epochs and from correction data for at least one of the epochs, comprising at least one processor with instructions enabling the at least one processor to

determine a first-epoch rover position relative to a first-epoch moving base location,

determine a second-epoch update of the first-epoch rover position relative to a second-epoch moving base location using a single-differenced delta phase process,

combine the first-epoch position and the second-epoch update to obtain a second-epoch rover position relative to the second-epoch moving base location, and

determine for each of a plurality of subsequent epochs a subsequent-epoch update and use the subsequent-epoch update to obtain a subsequent-epoch rover position relative to a moving base location of the subsequent epoch,

wherein the instructions further enable the at least one processor to repeatedly determine a first-epoch rover position relative to a moving base location at a first rate, and to repeatedly determine a subsequent-epoch update at a second rate which is higher than the first rate.

9. The apparatus of claim 8, wherein the rover position relative to the moving base location at each epoch represents a vector defining a heading.

10. The apparatus of claim 8, wherein the antenna of the GNSS rover and an antenna of a GNSS moving-base station are affixed to a movable object, such that at each epoch the rover position relative to the moving base location represents a vector defining an orientation of the movable object.

11. The apparatus of claim 8, wherein the instructions further enable the at least one processor to determine a first-epoch moving base location relative to a fixed-base location, using fixed-base correction data which comprises at least one of:

correction data prepared from observations of a physical base station, correction data prepared from observations of a network of reference stations, correction data prepared from observations of a global network of reference stations, and correction data prepared from observations of a regional network of reference stations.

12. The apparatus of claim 8, wherein the instructions further enable the at least one processor to determine for each epoch a rover position relative to a moving base location which defines a vector defining a heading for such epoch.

13. The apparatus of claim 8, wherein the instructions further enable the at least one processor to determine the moving base location based on one of (i) fixed carrier-phase ambiguities and (ii) a weighted average of carrier-phase ambiguity candidates which is converged to a predetermined threshold.

14. A method of determining a position of an antenna of a GNSS rover from observations of GNSS signals collected at the antenna over multiple epochs and from correction data for at least one of the epochs, comprising:

determining a first-epoch rover position relative to a first-epoch moving base location, wherein the first-epoch moving base location is based on weighted average of carrier-phase ambiguity candidates which is converged to a predetermined threshold,

determining a second-epoch update of the first-epoch rover position relative to a second-epoch moving base location using a single-differenced delta phase process, and

combining the first-epoch rover position and the second-epoch update to obtain a second-epoch rover position relative to the second-epoch moving base location.

15. A computer program product comprising:

a non-transitory computer usable medium having computer readable instructions physically embodied therein, the computer readable instructions when executed by a processor enabling the processor to perform the method of claim 14.

16. Apparatus for determining a position of an antenna of a GNSS rover from observations of GNSS signals collected at the antenna over multiple epochs and from correction data for at least one of the epochs, comprising at least one processor with instructions enabling the at least one processor to

determine a first-epoch rover position relative to a first-epoch moving base location, wherein the first-epoch moving base location is based on a weighted average of carrier-phase ambiguity candidates which is converged to a predetermined threshold,

determine a second-epoch update of the first-epoch rover position relative to a second-epoch moving base location using a single-differenced delta phase process, and

combine the first-epoch position and the second-epoch update to obtain a second-epoch rover position relative to the second-epoch moving base location.