Refining a position estimate of a low earth orbiting satellite

• US 9,121,932 B2
• Filed: 06/27/2013
• Issued: 09/01/2015
• Est. Priority Date: 01/10/2008
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Janky, James M., Talbot, Nicholas C., Vollath, Ulrich, Riter, Bruce D.
• Primary Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US13/929,302
• Publication Number:
  US 20130332072A1
• Time in Patent Office: 796 Days
• Field of Search: 701/13, 701/469, 701/742, 342/357.25, 342/357.43, 342/357.44
• US Class Current: 1/1
• CPC Class Codes: G01S 19/07 providing data for correcting measured positioning data, e.g. DGPS [differential GPS] or ionosphere corrections
• CPC Class Codes: G01S 19/40 Correcting position, velocity or attitude

Abstract

In a method for refining a position estimate of a low earth orbiting (LEO) satellite a first position estimate of a LEO satellite is generated with a GNSS receiver on-board the LEO satellite. Corrections are received at the LEO satellite. The corrections are processed on-board the LEO satellite such that a corrected LEO satellite position estimate of the LEO satellite is generated for the first position estimate.

Claims

1. A method for refining a position estimate of a low earth orbiting (LEO) satellite, said method comprising:

generating a first position estimate of a LEO satellite with a GNSS receiver on-board said LEO satellite;

receiving corrections at said LEO satellite; and

processing said corrections on-board said LEO satellite such that a corrected LEO satellite position estimate of said LEO satellite is generated for said first position estimate.

2. The method as recited in claim 1, further comprising communicating said first position estimate to a Virtual Reference Station (VRS) processor by:

transmitting said first position estimate using a telemetry downlink to communicate said first position estimate from said LEO satellite, wherein said downlink is further coupled to a communications network configured for delivering said first position estimate to a VRS processor.

3. The method as recited in claim 2, wherein said communicating said first position estimate to a VRS processor comprises:

formatting said first position estimate into a GNSS information message along with an identifier associated with said LEO satellite; and

communicating said GNSS information message to said VRS processor.

4. The method as recited in claim 1, further comprising:

utilizing said corrected LEO position estimate as an input to an orbit control system of said LEO satellite.

5. The method as recited in claim 1, further comprising:

transmitting said corrected LEO satellite position estimate from said LEO satellite for receipt by a GNSS rover receiver.

6. The method as recited in claim 5, wherein said transmitting said corrected LEO satellite position estimate from said LEO satellite for receipt by a GNSS rover receiver comprises:

transmitting said corrected LEO satellite position estimate over a communications channel of said LEO satellite for receipt by a terrestrial GNSS rover receiver, said GNSS rover receiver being configured with a LEO compatible receiver for reception of said LEO corrected satellite position estimate.

7. The method as recited in claim 1, wherein said generating a first position estimate of a LEO satellite with a GNSS receiver on-board said LEO satellite comprises:

receiving signals from a plurality of GNSS satellites, said signals comprising GNSS observables measured by said GNSS receiver; and

generating said first position estimate from said signals using said GNSS receiver.

8. The method as recited in claim 1, wherein said receiving corrections at said LEO satellite comprises:

receiving Virtual Reference Station (VRS) corrections.

9. The method as recited in claim 1, wherein said receiving corrections at said LEO satellite comprises:

receiving precise point positioning (PPP) corrections.

10. The method as recited in claim 9, further comprising:

transmitting said PPP corrections from said LEO satellite for receipt by a GNSS rover receiver.

11. The method as recited in claim 1, wherein said processing said corrections on-board said LEO satellite such that a corrected LEO satellite position estimate of said LEO satellite is generated for said first position estimate comprises:

processing said corrections to correct for errors in GNSS observables measured by said GNSS receiver.

12. A positioning and navigation system comprising:

a global navigation satellite system (GNSS) receiver, coupled with a Low Earth Orbiting (LEO) satellite and configured for measuring GNSS broadcast observables for use in generating a first position estimate indicative of an approximate position of said LEO satellite; and

a corrections processor for processing said corrections on-board said LEO satellite such that a corrected LEO satellite position estimate is produced.

13. The system of claim 12, further comprising:

a communications path configured for transmitting a corrections message between said a corrections processor and said LEO satellite, said corrections message comprising precise point positioning (PPP) corrections.

14. The system of claim 13, wherein said communications path comprises:

a communicative coupling between a PPP processor and a control station for said LEO satellite; and

a telemetry uplink between said control station and said LEO satellite.

15. The system of claim 12, further comprising:

a communications path configured for transmitting a corrections message between said a corrections processor and said LEO satellite, said corrections message comprising virtual reference station (VRS) corrections.

16. The system of claim 15, wherein said communications path comprises:

a communicative coupling between a VRS processor and a control station for said LEO satellite; and

a telemetry uplink between said control station and said LEO satellite.

17. The system of claim 12, further comprising:

a communications path configured for transmitting said corrected LEO satellite position estimate to a GNSS rover receiver, wherein said communication path comprises a LEO satellite downlink communications channel.

18. A low earth orbiting (LEO) satellite position determination system, said system comprising:

a global navigation satellite system (GNSS) receiver coupled with a LEO satellite, and configured for measuring GNSS broadcast observables for use in generating a first position estimate indicative of an approximate position of said LEO satellite;

a communications subsystem of said LEO satellite, configured for receiving a radio frequency message comprising a corrections message generated by an external source, said corrections message comprising corrections; and

a corrections processor for processing a received corrections message on-board said LEO satellite such that a corrected LEO satellite position estimate is generated from said corrections.

19. The system of claim 18, further comprising:

a communicative coupling between said corrections processor and an orbit control subsystem of said LEO satellite, said communicative coupling for providing said corrected LEO satellite position estimate as an input to said orbit control subsystem.

20. The system of claim 18, wherein said communications subsystem is further configured for transmitting said corrected LEO satellite position estimate from said LEO satellite for receipt by a GNSS rover receiver.

21. The system of claim 20, wherein said rover receiver comprises a space borne GNSS receiver.

22. The system of claim 20, wherein said GNSS rover receiver comprises a terrestrial GNSS rover receiver configured with a LEO receiver.

23. The system of claim 20, wherein said GNSS rover receiver comprises a subscribed client, wherein said LEO corrected satellite position estimate is transmitted by an antenna system of said LEO satellite to said subscribed client in exchange for a fee.

24. A non-transitory computer readable medium comprising instructions thereon which, when executed, cause a processor to perform a method for refining a position estimate of a LEO satellite, said method comprising:

generating a first position estimate of said LEO satellite with a GNSS receiver on-board said LEO satellite;

receiving corrections at said LEO satellite; and

processing said corrections on-board said LEO satellite such that a corrected LEO satellite position estimate of said LEO satellite is generated for said first position estimate.

25. The non-transitory computer readable medium of claim 24, further comprising communicating said first position estimate to a Virtual Reference Station (VRS) processor by:

transmitting said first position estimate using a telemetry downlink to communicate said first position estimate from said LEO satellite, wherein said downlink is further coupled to a communications network configured for delivering said first position estimate to a VRS processor.

26. The non-transitory computer readable medium of claim 25, wherein said communicating said first position estimate to a VRS processor comprises:

formatting said first position estimate into a GNSS information message along with an identifier associated with said LEO satellite; and

communicating said GNSS information message to said VRS processor.

27. The non-transitory computer readable medium of claim 24, further comprising:

utilizing said corrected LEO position estimate as an input to an orbit control system of said LEO satellite.

28. The non-transitory computer readable medium of claim 25, further comprising:

transmitting said corrected LEO satellite position estimate from said LEO satellite for receipt by a GNSS rover receiver.

29. The non-transitory computer readable medium of claim 28, wherein said transmitting said corrected LEO satellite position estimate from said LEO satellite for receipt by a GNSS rover receiver comprises:

transmitting said corrected LEO satellite position estimate over a communications channel of said LEO satellite for receipt by a terrestrial GNSS rover receiver, said GNSS rover receiver being configured with a LEO compatible receiver for reception of said LEO corrected satellite position estimate.

30. The non-transitory computer readable medium of claim 24, wherein said generating a first position estimate of a LEO satellite with a GNSS receiver on-board said LEO satellite comprises:

receiving signals from a plurality of GNSS satellites, said signals comprising GNSS observables measured by said GNSS receiver; and

generating said first position estimate from said signals using said GNSS receiver.

31. The non-transitory computer readable medium of claim 24, wherein said receiving corrections at said LEO satellite comprises:

receiving Virtual Reference Station (VRS) corrections.

32. The non-transitory computer readable medium of claim 24, wherein said receiving corrections at said LEO satellite comprises:

receiving precise point positioning (PPP) corrections.

33. The non-transitory computer readable medium of claim 32, further comprising:

transmitting said PPP corrections from said LEO satellite for receipt by a GNSS rover receiver.

34. The non-transitory computer readable medium of claim 24, wherein said processing said corrections on-board said LEO satellite such that a corrected LEO satellite position estimate of said LEO satellite is generated for said first position estimate comprises:

processing said corrections to correct for errors in GNSS observables measured by said GNSS receiver.