SYSTEM AND METHOD OF REFERENCE POSITION DETERMINATION

• US 20110305260A1
• Filed: 12/02/2009
• Published: 12/15/2011
• Est. Priority Date: 12/05/2008
• Status: Abandoned Application

• Current Assignee: Leica Geosystems AG (Hexagon AB)
• Original Assignee: Leica Geosystems AG (Hexagon AB)
• Inventors: McManus, Ian
• Application Number:
  US13/130,036
• Publication Number:
  US 20110305260A1
• Time in Patent Office: Days
• US Class Current: 375/130
• CPC Class Codes: G01S 19/071 DGPS corrections
• CPC Class Codes: G01S 19/50 whereby the position solution is constrained to lie upon a particular curve or surface, e.g. for locomotives on railway tracks

Abstract

A method of reference position determination for a DGNSS base station. The base station comprises a memory, a logic controller and a GNSS receiver. Stored reference positions are stored in the memory as coordinate sets comprising components. The GNSS receiver determines a current estimate position of the base station as a coordinate set comprising components. The logic controller retrieves a stored reference position, converts the components of the stored reference position and the current estimate position to binary string format. The current estimate position is matched to the stored reference position by matching the binary string format components of the current estimate position with the binary string format components of the stored reference position. If the stored reference position is matched to the current estimate position, the base station is assigned the stored reference position as its reference position.

Claims

1. A method of reference position determination for a DGNSS base station, the method including the steps of:

determining a current estimate position of the base station as a number of components of a coordinate set using a GNSS receiver;

retrieving a stored reference position, from one or more stored reference positions which are stored in a memory of the base station, as a number of components of a coordinate set;

converting two or more of the components of each of the coordinate sets of the stored reference position and the current estimate position to binary string format;

matching the current estimate position to the stored reference position by matching two or more of the binary string format components of the current estimate position with two or more of the binary string format components of the stored reference position; and

assigning the base station a reference position being one of the stored reference positions if the stored reference position is matched to the current estimate position in the matching operation.

2. The method of claim 1, wherein all of the components of each of the coordinate sets of the stored reference position and the current estimate position is converted to binary string format.

3. The method of claim 1, wherein all of the binary string format components of the current estimate position are matched with the binary string format components of the stored reference position.

4. The method of claim 1, wherein matching of the current estimate position with the stored reference position includes matching each component of the binary string format coordinate set of the current estimate position with a corresponding component of the binary string format coordinate set of the stored reference position.

5. The method of claim 1, wherein the method includes the step of manipulating one or both of the coordinate sets of the stored reference position and the current estimate position before matching the components of the coordinate sets.

6. The method of claim 1, wherein the method includes the step of calculating a new reference position and assigning the base station the new reference position if none of the stored reference positions match the current estimate position.

7. The method of claim 6, wherein the method includes the step of storing the new reference position in the memory of the base station as a stored reference position.

8. The method of claim 5, wherein manipulation of the coordinate sets include offsetting the components of the coordinate sets by a fixed value to ensure the coordinate sets comprise only positive components.

9. The method of claim 5, wherein manipulation of the coordinate sets include scaling of the components of the coordinate sets.

10. The method of claim 8, wherein the components of the coordinate sets are scaled after the components have been offset.

11. The method of claim 9, wherein scaling of the coordinate sets comprise dividing each of the components by a scaling factor.

12. The method of claim 1, wherein matching of the components of the coordinate sets include taking into account a lowest bit change in each of the components so that components having a difference only at the lowest bit are matched.

13. The method of claim 1, wherein matching of the current estimate position to the stored reference position comprises:

concatenating the binary string format components of each of the current estimate position and the stored reference position;

performing a checksum algorithm on the concatenated binary string format components to determine a position checksum for each of the current estimate position and the stored reference position; and

comparing the position checksums to determine a match.

16. The method of claim 10, wherein scaling of the coordinate sets comprise dividing each of the components by a scaling factor.

14. A system for reference position determination including a DGNSS base station which comprises:

a memory for storing one or more stored reference positions as coordinate sets comprising components;

a GNSS receiver for determining a current estimate position of the base station as a coordinate set comprising components; and

a logic controller which is operable to;

convert two or more of the components of each of the coordinate sets of the stored reference position and the current estimate position to binary string format;

match the current estimate position to the stored reference position by matching two or more of the binary string format components of the current estimate position with two or more of the binary string format components of the stored reference position; and

assign the base station a reference position being one of the stored reference positions if the stored reference position is matched to the current estimate position.

15. A computer readable storage medium with an executable program stored thereon, wherein the program instructs a logic controller to perform the following steps:

converting two or more of the components of a coordinate set of a stored reference position stored in a memory to binary string format;

converting two or more of the components of a coordinate set of a current estimate position determined by a GNSS receiver to binary string format;

matching the current estimate position to the stored reference position by matching two or more of the binary string format components of the current estimate position with two or more of the binary string format components of the stored reference position; and

assigning the base station a reference position being one of the stored reference positions if the stored reference position is matched to the current estimate position.