Automated differential correction processing of field data in a global positional system

• US 6,144,335 A
• Filed: 04/14/1998
• Issued: 11/07/2000
• Est. Priority Date: 04/14/1998
• Status: Expired due to Term

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: France, Peter Glen, Rogers, John F.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US09/060,363
• Time in Patent Office: 938 Days
• Field of Search: 342/357.03, 342/357.02, 701/215, 701/214
• US Class Current: 342/357.27
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]
• CPC Class Codes: G01S 19/43 using carrier phase measurements, e.g. kinematic positioning; using long or short baseline interferometry

Abstract

A system and method for automated differential correction processing of field data in a global positioning system (GPS). In one embodiment, the present invention retrieves GPS field data collected by one or more GPS receivers from a storage device, and then automatically selects the most appropriate differential correction scheme to generate a solution without user intervention. More specifically, the present invention executes a code-based correction scheme to generate a code-based solution for the field data. Next, the present invention examines the field data to determine whether a carrier phase correction is applicable. If the field data supports carrier phase correction, the present invention generates a carrier phase solution, compares it with the code-based solution, and returns the more accurate of the two solutions as the final result. If the field data does not support a carrier phase correction, the present invention returns the code-based solution as the final result. Thus, the present invention provides a system and method for post-processing of GPS field data which does not require a user to know and understand the contents of the field data, to deal with multiple user interfaces, or to read and interpret different results generated by various processing schemes. In other words, the present invention provides a single software package for post-processing of GPS field data without extensive user involvement. As such, the present invention greatly reduces the complexity of GPS field data post-processing and enhances the usability of GPS equipment.

Claims

1. In a global positioning system (GPS), a method for differential correction processing of a set of GPS field data, said method comprising the computer implemented steps of:

a) retrieving said set of GPS field data from a field data storage device;

b) automatically identifying a most appropriate one of a plurality of correction schemes for said set of GPS field data; and

c) generating a differential GPS solution for said set of GPS field data with said most appropriate correction scheme.

2. The method as recited in claim 1 wherein said step b) further comprises the computer implemented steps of:

b1) executing a first correction scheme to generate a first solution;

b2) determining whether a second correction scheme is applicable to said set of GPS field data;

b3) provided that said second correction scheme is applicable, analyzing said set of GPS field data to generate a second solution according to said second correction scheme; and

b4) selectively identifying a more accurate one of said first solution and said second solution as said differential GPS solution.

3. The method as recited in claim 2 further comprising the computer implemented step of:

b5) provided that said second correction scheme is inapplicable, identifying said first solution as said differential GPS solution.

4. The method as recited in claim 2 wherein said step b4) further comprises the computer implemented steps of:

analyzing said set of GPS field data to generate a first accuracy indicator pertaining to said first solution;

analyzing said set of GPS field data to generate a second accuracy indicator pertaining to said second solution; and

comparing said first accuracy indicator and said second accuracy indicator.

5. The method as recited in claim 2 wherein said step b3) further comprises the computer implemented steps of:

executing a third correction scheme;

determining whether said third correction scheme is successful in generating a third solution; and

provided that said third correction scheme is successful in generating said third solution, identifying said third solution as said second solution.

6. The method as recited in claim 5 wherein said step b3) further comprises the computer implemented steps of:

provided that said third correction scheme is unsuccessful in generating said third solution, executing a fourth correction scheme;

determining whether said fourth correction scheme is successful in generating a fourth solution;

provided that said fourth correction scheme is successful in generating said fourth solution, identifying said fourth solution as said second solution; and

provided that said fourth correction scheme is unsuccessful in generating said fourth solution, indicating that said second solution is unachievable.

7. The method as recited in claim 2 wherein said first correction scheme is a code-based correction scheme.

8. The method as recited in claim 2 wherein said second correction scheme is a carrier phase correction scheme.

9. The method as recited in claim 5 wherein said third correction scheme is a fixed integer correction scheme.

10. The method as recited in claim 6 wherein said fourth correction scheme is a floating point correction scheme.

11. The method as recited in claim 4 wherein said first accuracy indicator and said second accuracy indicator are statistically computed from said set of GPS field data.

12. The method as recited in claim 1 wherein said method is performed without user intervention.

13. A computer system including a processor, an address/data bus coupled to said processor, and a computer readable memory coupled to communicate with said processor, said processor for performing a method for differential correction processing in a global positioning system (GPS), said method comprising the steps of:

a) retrieving a set of GPS field data from a field data storage device;

b) automatically identifying a most appropriate one of a plurality of correction schemes for said set of GPS field data; and

c) generating a differential GPS solution for said set of GPS field data with said most appropriate correction scheme.

14. The computer system as recited in claim 13 wherein said step b) further comprises the steps of:

b1) executing a first correction scheme to generate a first solution;

b2) determining whether a second correction scheme is applicable to said set of GPS field data;

b3) provided that said second correction scheme is applicable, analyzing said set of GPS field data to generate a second solution according to said second correction scheme; and

b4) selectively identifying a more accurate one of said first solution and said second solution as said differential GPS solution.

15. The computer system as recited in claim 14 further comprising the step of:

b5) provided that said second correction scheme is inapplicable, identifying said first solution as said differential GPS solution.

16. The computer system as recited in claim 14 wherein said step b4) further comprises the steps of:

analyzing said set of GPS field data to generate a first accuracy indicator pertaining to said first solution;

analyzing said set of GPS field data to generate a second accuracy indicator pertaining to said second solution; and

comparing said first accuracy indicator and said second accuracy indicator.

17. The computer system as recited in claim 14 wherein said step b3) further comprises the steps of:

executing a third correction scheme;

determining whether said third correction scheme is successful in generating a third solution; and

provided that said third correction scheme is successful in generating said third solution, identifying said third solution as said second solution.

18. The computer system as recited in claim 17 wherein said step b3) further comprises the steps of:

provided that said third correction scheme is unsuccessful in generating said third solution, executing a fourth correction scheme;

determining whether said fourth correction scheme is successful in generating a fourth solution;

provided that said fourth correction scheme is successful in generating said fourth solution, identifying said fourth solution as said second solution; and

provided that said fourth correction scheme is unsuccessful in generating said fourth solution, indicating that said second solution is unachievable.

19. The computer system as recited in claim 14 wherein said first correction scheme is a code-based correction scheme.

20. The computer system as recited in claim 14 wherein said second correction scheme is a carrier phase correction scheme.

21. The computer system as recited in claim 17 wherein said third correction scheme is a fixed integer correction scheme.

22. The computer system as recited in claim 18 wherein said fourth correction scheme is a floating point correction scheme.

23. The computer system as recited in claim 16 wherein said first accuracy indicator and said second accuracy indicator are statistically computed from said set of GPS field data.

24. The computer system as recited in claim 13 wherein said method is performed without user intervention.

25. In a global positioning system (GPS), a computer-usable medium having computer-readable program code embodied therein for causing a computer to perform the steps of:

a) retrieving a set of GPS field data from a field data storage device;

b) automatically identifying a most appropriate one of a plurality of correction schemes for said set of GPS field data; and

c) generating a differential GPS solution for said set of GPS field data with said most appropriate correction scheme.

26. The computer-usable medium as recited in claim 25 wherein said step b) further comprises the steps of:

b1) executing a first correction scheme to generate a first solution;

b2) determining whether a second correction scheme is applicable to said set of GPS field data;

b3) provided that said second correction scheme is applicable, analyzing said set of GPS field data to generate a second solution according to said second correction scheme; and

b4) selectively identifying a more accurate one of said first solution and said second solution as said differential GPS solution.

27. The computer-usable medium as recited in claim 26 further comprising the step of:

b5) provided that said second correction scheme is inapplicable, identifying said first solution as said differential GPS solution.

28. The computer-usable medium as recited in claim 26 wherein said step b4) further comprises the steps of:

analyzing said set of GPS field data to generate a first accuracy indicator pertaining to said first solution;

analyzing said set of GPS field data to generate a second accuracy indicator pertaining to said second solution; and

comparing said first accuracy indicator and said second accuracy indicator.

29. The computer-usable medium as recited in claim 26 wherein said step b3) further comprises the steps of:

executing a third correction scheme;

determining whether said third correction scheme is successful in generating a third solution; and

provided that said third correction scheme is successful in generating said third solution, identifying said third solution as said second solution.

30. The computer-usable medium as recited in claim 29 wherein said step b3) further comprises the steps of:

provided that said third correction scheme is unsuccessful in generating said third solution, executing a fourth correction scheme;

determining whether said fourth correction scheme is successful in generating a fourth solution;

provided that said fourth correction scheme is successful in generating said fourth solution, identifying said fourth solution as said second solution; and

provided that said fourth correction scheme is unsuccessful in generating said fourth solution, indicating that said second solution is unachievable.

31. The computer system as recited in claim 26 wherein said first correction scheme is a code-based correction scheme.

32. The computer system as recited in claim 26 wherein said second correction scheme is a carrier phase correction scheme.

33. The computer system as recited in claim 29 wherein said third correction scheme is a fixed integer correction scheme.

34. The computer system as recited in claim 30 wherein said fourth correction scheme is a floating point correction scheme.

35. The computer system as recited in claim 28 wherein said first accuracy indicator and said second accuracy indicator are statistically computed from said set of GPS field data.

36. The computer system as recited in claim 25 wherein said steps are performed without user intervention.