Method and apparatus for compression of long term orbit data

• US 20070282910A1
• Filed: 03/15/2007
• Published: 12/06/2007
• Est. Priority Date: 06/06/2001
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Global Locate Incorporated (Broadcom, Inc.)
• Inventors: Podshivalov, Sergei, Abraham, Charles, De Salas, Javier, Diggelen, Frank, Riben, Matt
• Granted Patent: US 8,090,536 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B64G 1/1014 Navigation satellites
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/258 relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
• CPC Class Codes: G01S 19/27 creating, predicting or correcting ephemeris or almanac data within the receiver

Abstract

A method and apparatus for processing long term orbit data that is valid for an extended period of time into the future (i.e., long term orbit data). The long term orbit data is processed by reducing redundant information from the data to form compressed long term orbit data.

Claims

1. A method for processing long term orbit data comprising:

receiving long term orbit data; and

reducing redundant information from the long term orbit data to form compressed long term orbit data.

2. The method of claim 1 further comprising omitting terms from the long term orbit data when said terms can be reconstructed from the remaining data.

3. The method of claim 1 wherein said long term orbit data comprises:

long term orbit data for each satellite of a plurality of satellites forming a set of long term orbit data.

4. The method of claim 2 wherein the removing step further comprises:

identifying a first long term orbit data for at least one satellite as a reference data for said at least one satellite

subtracting a second long term orbit data from the reference data to form a delta data, for said at least one satellite.

5. The method of claim 4 wherein the first long term satellite orbit data is selected from the set of long term satellite orbit data.

6. The method of claim 4 wherein the first long term satellite orbit data is derived by using information from the set of long term satellite orbit data.

7. The method of claim 4 wherein the first long term satellite orbit data is arbitrary.

8. The method of claim 4 further comprising forming a compressed data set comprising the reference data and the delta data.

9. The method of claim 8 wherein the compressed data set further comprises a dynamic range map.

10. The method of claim 8 wherein the compressed data set further comprises an indicator of whether a field is compressed.

11. The method of claim 8 wherein the compressed data set comprises scale factors of the delta data.

12. The method of claim 1 wherein said producing step further comprises:

generating satellite orbit data for a past period of time; and

extending the satellite orbit data into the future.

13. The method of claim 1 wherein said producing step further comprises:

generating satellite clock offset data for a past period of time; and

extending the satellite clock offset data into the future.

14. The method of claim 1 further comprising:

transmitting the compressed long term bit data to a global navigation satellite system (GNSS) receiver using a wireless communications link.

15. A method for processing long term orbit data comprising:

receiving long term orbit data;

creating a reference long term orbit data; and

creating at least one delta long term orbit data representing differences between the reference long term orbit data and other long term orbit data.

16. The method of claim 15 wherein the reference long term orbit data is actual long term orbit data selected from a set of long term orbit data or arbitrary long term orbit data.

17. The method of claim 15 wherein the creating a plurality of delta long term orbit data further comprises:

computing a difference between at least one term of one of the other long term orbit data and at least one term of the reference long term orbit data.

18. The method of claim 15 further comprising:

generating a dynamic range map for the delta long term orbit data.

19. The method of claim 15 further comprising:

generating a bitmask that indicates whether a term of the other long term orbit data is compressed.

20. The method of claim 15 further comprising omitting terms from the delta long term orbit data when said terms can be reconstructed from the remaining data.

21. The method of claim 15 further comprising:

arranging the reference long term orbit data and the delta long term orbit data to form a compressed data set.

22. The method of claim 15 further comprising:

reconstructing a set of long term orbit data using the reference long term orbit data and the delta long term orbit data.

23. The method of claim 22 wherein the reconstructing step further comprises:

adding a delta term to a reference term.

24. The method of claim 22 wherein the reconstructing step further comprises:

using a rate term.

25. The method of claim 24 wherein said rate term is multiplied by a time difference.

26. Apparatus for processing long term orbit data comprising:

means for receiving long term orbit data; and

means for reducing redundant information from the long term orbit data to form compressed long term orbit data.