DISTRIBUTED ORBIT MODELING AND PROPAGATION METHOD FOR A PREDICTED AND REAL-TIME ASSISTED GPS SYSTEM

• US 20080018527A1
• Filed: 04/25/2007
• Published: 01/24/2008
• Est. Priority Date: 04/25/2006
• Status: Active Grant

• Current Assignee: Rx Networks Inc. (Beijing BDStar Navigation Co., Ltd.)
• Original Assignee: Rx Networks Inc. (Beijing BDStar Navigation Co., Ltd.)
• Inventors: LaMance, James, Eagen, Maria, Roy-MacHabee, Guylain
• Granted Patent: US 7,612,712 B2
• Time in Patent Office: Days
• US Class Current: 342/357.1
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• 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
• CPC Class Codes: H04W 4/02 Services making use of location information

Abstract

A distributed orbit and propagation method for use in a predicted GPS or GNSS system, which includes a predicted GPS server (PGPS Server), a source of high accuracy orbit predictions (Orbit Server), a global reference network (GRN Server) providing real-time GPS or GNSS assistance data to the PGPS Server, a predicted GPS client (PGPS Client) running on a device equipped with a GPS or AGPS chipset. In response to requests from the PGPS Client, the PGPS Server produces and disseminates an initial seed dataset consisting of current satellite orbit state vectors and orbit propagation model coefficients. This seed dataset enables the PGPS Client to locally predict and propagate satellite orbits to a desired future time. This predictive assistance in turn helps accelerate Time To First Fix (TTFF), optimize position solution calculations and improve the sensitivity of the GPS chip present on, or coupled with, the device. In contrast with other conventional predicted GPS systems that forward large volumes of predicted orbits, synthetic ephemeris or synthetic almanac data, this method optimally reduces data transfer requirements to the client, and enables the client to locally synthesize its own predicted assistance data as needed. This method also supports seamless notification of real-time satellite integrity events and seamless integration of predicted assistance data with industry standard real-time assistance data.

Claims

1. A distributed GPS or GNSS method of orbit modeling and propagation, comprising:

(a) computing GNSS satellite force model parameters using a Predicted GPS (PGPS) Server;

(b) delivering said GNSS satellite force model parameters and an initial GNSS satellite position and velocity to a Predicted GPS (PGPS) Client via a communications link,

(c) generating within said Predicted GPS (PGPS) Client a predicted Orbital State Vector (OSV) comprising a satellite position and velocity, by propagating the initial satellite position and velocity provided by said Predicted GPS (PGPS) Server to a different time than the time of said initial satellite position and velocity, using said GNSS satellite force model parameters provided by said Predicted GPS (PGPS) server to said Predicted GPS (PGPS) Client; and

(d) providing a local GPS or AGPS device with assistance data derived from said predicted Orbital State Vector (OSV) without requiring a real-time network connection;

wherein said assistance data is derived by converting said predicted Orbital State Vector (OSV) into the so-called satellite navigation data model format and provided by said Predicted GPS (PGPS) Client to said GPS or AGPS device at a time and in a format required by said GPS or AGPS device.

2. The method of claim 1, wherein the initial satellite position and velocity is provided to the Predicted GPS (PGPS) Client as a change to a previously delivered satellite position and velocity.

3. The method of claim 1, wherein the initial satellite position and velocity is provided to the Predicted GPS (PGPS) Client as a change from a propagated predicted Orbital State Vector (OSV) based on a previously delivered satellite position and velocity.

4. The method of claim 1, wherein the GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client as a change to previously delivered GNSS satellite force model parameters.

5. The method of claim 1, wherein the initial satellite position and velocity and the GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client as a change to previously delivered initial satellite position and velocity and to previously delivered GNSS satellite force model parameters.

6. The method of claim 1, wherein the satellite position and velocity and GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client in a compressed format.

7. The method of claim 2, wherein the changes in satellite position and velocity are provided to the Predicted GPS (PGPS) Client in a compressed format.

8. The method of claim 3, wherein the satellite position and velocity are provided to the Predicted GPS (PGPS) Client in a compressed format.

9. The method of claim 4, wherein the changes in GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client in a compressed format.

10. The method of claim 5, wherein the changes in satellite position and velocity and GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client in a compressed format.

11. The method of claim 1, wherein the Predicted GPS (PGPS) Client is hosted on a mobile device.

12. The method of claim 1, wherein the Predicted GPS (PGPS) Client is hosted on a device that does not have a local GPS or AGPS device.

13. The method of claim 1, wherein the Predicted GPS (PGPS) Client delivers assistance data to the local GPS or AGPS device in the so-called satellite navigation data model format by way of a built-in AGPS server that emulates the functionality of a standard remote AGPS server.

14. The method of claim 1, wherein the Predicted GPS (PGPS) Client delivers assistance data to GPS or AGPS devices that are not local to said Predicted GPS (PGPS) Client in the so-called satellite navigation data model format by way of a built-in AGPS server that emulates the functionality of a standard remote AGPS server.

15. The method of claim 1, wherein the Predicted GPS (PGPS) Server computes GNSS satellite force model parameters using a plurality of GNSS satellite force models, and wherein the Predicted GPS (PGPS) Client generates predicted Orbital State Vectors (OSV) by propagating provided initial satellite position and velocity provided by said Predicted GPS (PGPS) Server using GNSS satellite force model parameters from one or more of available ones of said GNSS satellite force models provided by said Predicted GPS (PGPS) server.

16. A distributed GPS or GNSS method of orbit modeling and propagation, comprising:

(a) computing GNSS satellite force model parameters using a Predicted GPS (PGPS) Server;

(b) delivering said GNSS satellite force model parameters and a plurality of GNSS satellite position and velocity Orbital State Vectors (OSV'"'"'s) via a communications link;

(c) generating within said Predicted GPS (PGPS) Client a predicted Orbital State Vector (OSV) comprising a satellite position and velocity, by propagating the initial satellite position and velocity provided by said Predicted GPS (PGPS) Server to a different time than the time of said initial satellite position and velocity, using said GNSS satellite force model parameters provided by said Predicted GPS (PGPS) server to said Predicted GPS (PGPS) Client; and

(d) providing a local GPS or AGPS device with assistance data derived from said predicted Orbital State Vector (OSV) without requiring a real-time network connection;

wherein said assistance data is derived by converting said predicted Orbital State Vector (OSV) into the so-called satellite navigation data model format and provided by said Predicted GPS (PGPS) Client to said GPS or AGPS device at a time and in a format required by said GPS or AGPS device.

17. A distributed GPS or GNSS method of orbit modeling and propagation, comprising:

(a) computing GNSS satellite force model parameters using a Predicted GPS (PGPS) Server;

(b) delivering said GNSS satellite force model parameters and an initial GNSS satellite position and velocity to a Predicted GPS (PGPS) Client via a communications link,

(c) generating within said Predicted GPS (PGPS) Client a predicted Orbital State Vector (OSV) comprising a satellite position and velocity, by propagating the initial satellite position and velocity provided by said Predicted GPS (PGPS) Server to a different time than the time of said initial satellite position and velocity, using said GNSS satellite force model parameters provided by said Predicted GPS (PGPS) server to said Predicted GPS (PGPS) Client; and

(d) providing a local GPS or AGPS device with assistance data derived from said predicted Orbital State Vector (OSV) without requiring a real-time network connection;

wherein said assistance data consists of the satellite position and velocity contained in said predicted Orbital State Vector (OSV) without converting into the so-called satellite navigation data model format and provided by said Predicted GPS (PGPS) Client to said GPS or AGPS device at a time and in a format required by said GPS or AGPS device.

18. The method of claim 17, wherein the Predicted GPS (PGPS) Client is integrated into a GPS or AGPS device.

19. The method of claim 17, wherein the initial satellite position and velocity is provided to the Predicted GPS (PGPS) Client as a change to a previously delivered satellite position and velocity.

20. The method of claim 17, wherein the initial satellite position and velocity is provided to the Predicted GPS (PGPS) Client as a change from a propagated predicted Orbital State Vector (OSV) based on a previously delivered satellite position and velocity.

21. The method of claim 17, wherein the GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client as a change to previously delivered GNSS satellite force model parameters.

22. The method of claim 17, wherein the initial satellite position and velocity and the GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client as a change to the initial satellite position and velocity and to the GNSS satellite force model parameters from previously delivered initial satellite position and velocity and GNSS satellite force model parameters.

23. The method of claim 17, wherein the satellite position and velocity and GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client in a compressed format.

24. The method of claim 20, wherein the satellite position and velocity are provided to the Predicted GPS (PGPS) Client in a compressed format.

25. The method of claim 19, wherein the changes in satellite position and velocity are provided to the Predicted GPS (PGPS) Client in a compressed format.

26. The method of claim 21, wherein the changes in GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client in a compressed format.

27. The method of claim 22, wherein the changes in satellite position and velocity and GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client in a compressed format.

28. The method of claim 17, wherein the Predicted GPS (PGPS) Client is hosted on a mobile device.

29. The method of claim 17, wherein the Predicted GPS (PGPS) Client is hosted on a common CPU with the GPS or AGPS device.

30. The method of claim 17, wherein the Predicted GPS (PGPS) Client is hosted on a device that does not have a local GPS or AGPS device.

31. The method of claim 17, wherein the Predicted GPS (PGPS) Server computes GNSS satellite force model parameters using a plurality of GNSS satellite force models, and wherein the Predicted GPS (PGPS) Client generates predicted Orbital State Vectors (OSV) by propagating provided initial satellite position and velocity provided by said Predicted GPS (PGPS) Server using GNSS satellite force model parameters from one or more of available ones of said GNSS satellite force models provided by said Predicted GPS (PGPS) server.

32. A distributed GPS or GNSS method of orbit modeling and propagation, comprising;

(a) computing GNSS satellite force model parameters using a Predicted GPS (PGPS) Server;

(b) delivering said GNSS satellite force model parameters and a plurality of GNSS satellite position and velocity Orbital State Vectors (OSV'"'"'s) via a communications link;

(c) generating within said Predicted GPS (PGPS) Client a predicted Orbital State Vector (OSV) comprising a satellite position and velocity, by propagating the initial satellite position and velocity provided by said Predicted GPS (PGPS) Server to a different time than the time of said initial satellite position and velocity, using said GNSS satellite force model parameters provided by said Predicted GPS (PGPS) server to said Predicted GPS (PGPS) Client; and

(d) providing a local GPS or AGPS device with assistance data derived from said predicted Orbital State Vector (OSV) without requiring a real-time network connection;

wherein said assistance data consists of the satellite position and velocity contained in said predicted Orbital State Vector (OSV) without converting into the so-called satellite navigation data model format and provided by said Predicted GPS (PGPS) Client to said GPS or AGPS device at a time and in a format required by said GPS or AGPS device.

33. A real-time Assisted-GPS and distributed GPS or GNSS method of orbit modeling and propagation, comprising:

(a) computing GNSS satellite force model parameters using a Predicted GPS (PGPS) Server;

(b) providing real-time GPS assistance data using a Global Reference Network (GRN) Server,

(c) selectively delivering said real-time GPS assistance data and/or said GNSS satellite force model parameters and an initial GNSS satellite position and velocity to a Predicted GPS (PGPS) Client using a communications link;

(d) generating within said Predicted GPS (PGPS) Client a predicted Orbital State Vector (OSV) comprising a satellite position and velocity, by propagating the initial satellite position and velocity provided by said Predicted GPS (PGPS) Server to a different time than the time of said initial satellite position and velocity, using said GNSS satellite force model parameters provided by said Predicted GPS (PGPS) server to said Predicted GPS (PGPS) Client; and

(e) providing a local GPS or AGPS device with predicted assistance data derived from said predicted Orbital State Vector (OSV) when no real-time network connection is available, or providing a local GPS or AGPS device with either realtime GPS assistance data, or predicted assistance data derived from said predicted Orbital State Vector (OSV) when a real-time network connection is available;

wherein said predicted assistance data is derived by converting said predicted Orbital State Vector (OSV) into the so-called satellite navigation data model format and provided by said Predicted GPS (PGPS) Client to said GPS or AGPS device at a time and in a format required by said GPS or AGPS device;

and wherein said real-time assistance data is provided by said Predicted GPS (PGPS) Client to said GPS or AGPS device at a time and in a format required by said GPS or AGPS device.

34. The method of claim 33, wherein the initial satellite position and velocity is provided to the Predicted GPS (PGPS) Client as a change to a previously delivered satellite position and velocity.

35. The method of claim 33, wherein the initial satellite position and velocity is provided to the Predicted GPS (PGPS) Client as a change from a propagated predicted Orbital State Vector (OSV) based on a previously delivered satellite position and velocity.

36. The method of claim 33, wherein the GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client as a change to previously delivered GNSS satellite force model parameters.

37. The method of claim 33, wherein the initial satellite position and velocity and the GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client as a change to previously delivered initial satellite position and velocity and to previously delivered GNSS satellite force model parameters from previously delivered initial satellite position and velocity and GNSS satellite force model parameters.

38. The method of claim 33, wherein the satellite position and velocity and GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client in a compressed format.

39. The method of claim 34, wherein the changes in satellite position and velocity are provided to the Predicted GPS (PGPS) Client in a compressed format.

40. The method of claim 35, wherein the satellite position and velocity are provided to the Predicted GPS (PGPS) Client in a compressed format.

41. The method of claim 36, wherein the changes in GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client in a compressed format.

42. The method of claim 37, wherein the changes in satellite position and velocity and GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client in a compressed format.

43. The method of claim 33, wherein the Predicted GPS (PGPS) Client is hosted on a mobile device.

44. The method of claim 33, wherein the Predicted GPS (PGPS) Client is hosted on a device that does not have a local GPS or AGPS device.

45. The method of claim 33, wherein the Predicted GPS (PGPS) Client delivers assistance data to the local GPS or AGPS device in a satellite navigation data model format by way of a built-in AGPS server that emulates the functionality of a standard remote AGPS server.

46. The method of claim 33, wherein the Predicted GPS (PGPS) Client delivers assistance data to GPS or AGPS devices that are not local to said Predicted GPS (PGPS) Client in the satellite navigation data model format by way of a built-in AGPS server that emulates the functionality of a standard remote AGPS server.

47. The method of claim 33, wherein the Predicted GPS (PGPS) Server computes GNSS satellite force model parameters using a plurality of GNSS satellite force models, and wherein the Predicted GPS (PGPS) Client generates predicted Orbital State Vectors (OSV) by propagating provided initial satellite position and velocity using GNSS satellite force model parameters from one or more of available ones of said GNSS satellite force models.

48. The method of claim 37, wherein real-time satellite integrity information received from said GRN Server is provided to the Predicted GPS (PGPS) Client as a change to the initial satellite position and velocity and to the GNSS satellite force model parameters from previously delivered initial satellite position and velocity and GNSS satellite force model parameters, such that when there are satellite integrity events that cause the said initial satellite position and velocity and the said initial GNSS satellite force model parameters to be invalid, an update can be provided without requiring new initial satellite position and velocity and said initial GNSS satellite force model parameters being provided to the said Predicted GPS (PGPS) Client.

49. A real-time Assisted-GPS and distributed GPS or GNSS method of orbit modeling and propagation, comprising:

(a) computing GNSS satellite force model parameters using a Predicted GPS (PGPS) Server;

(b) providing real-time GPS assistance data using a Global Reference Network (GRN) Server;

(c) selectively delivering said real-time GPS assistance data and/or said GNSS satellite force model parameters and an initial GNSS satellite position and velocity to a Predicted GPS (PGPS) Client using a communications link;

(d) generating within said Predicted GPS (PGPS) Client a predicted Orbital State Vector (OSV) comprising a satellite position and velocity, by propagating the initial satellite position and velocity provided by said Predicted GPS (PGPS) Server to a different time than the time of said initial satellite position and velocity, using said GNSS satellite force model parameters provided by said Predicted GPS (PGPS) server to said Predicted GPS (PGPS) Client; and

(e) providing a local GPS or AGPS device with predicted assistance data derived from said predicted Orbital State Vector (OSV) when no realtime network connection is available, or providing a local GPS or AGPS device with either real-time GPS assistance data, or predicted assistance data derived from said predicted Orbital State Vector (OSV) when a real-time network connection is available;

wherein said predicted assistance data consists of the satellite position and velocity contained in said predicted Orbital State Vector (OSV) without converting into the so-called satellite navigation data model format and provided by said Predicted GPS (PGPS) Client to said GPS or AGPS device at a time and in a format required by said GPS or AGPS device and wherein said real-time assistance data is provided by said Predicted GPS (PGPS) Client to said GPS or AGPS device at a time and in a format required by said GPS or AGPS device.

50. The method of claim 49, wherein the Predicted GPS (PGPS) Client is integrated into the GPS or AGPS device.

51. The method of claim 49, wherein the initial satellite position and velocity is provided to the Predicted GPS (PGPS) Client as a change to a previously delivered satellite position and velocity.

52. The method of claim 49, wherein the initial satellite position and velocity is provided to the Predicted GPS (PGPS) Client as a change from a propagated predicted Orbital State Vector (OSV) based on a previously delivered satellite position and velocity.

53. The method of claim 49, wherein the GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client as a change to previously delivered GNSS satellite force model parameters.

54. The method of claim 49, wherein the initial satellite position and velocity and the GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client as a change to the initial satellite position and velocity and to the GNSS satellite force model parameters from previously delivered initial satellite position and velocity and GNSS satellite force model parameters.

55. The method of claim 49, wherein the satellite position and velocity and GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client in a compressed format.

56. The method of claim 52, wherein the satellite position and velocity are provided to the Predicted GPS (PGPS) Client in a compressed format.

57. The method of claim 51, wherein the changes in satellite position and velocity are provided to the Predicted GPS (PGPS) Client in a compressed format.

58. The method of claim 53, wherein the changes in GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client in a compressed format.

59. The method of claim 54, wherein the changes in satellite position and velocity and GNSS satellite force model parameters are provided to the Predicted GPS (PGPS) Client in a compressed format.

60. The method of claim 49, wherein the Predicted GPS (PGPS) Client is hosted on a mobile device.

61. The method of claim 49, wherein the Predicted GPS (PGPS) Client is hosted on a common CPU with the GPS or AGPS device.

62. The method of claim 49, wherein the Predicted GPS (PGPS) Client is hosted on a device that does not have a local GPS or AGPS device.

63. The method of claim 49, wherein the Predicted GPS (PGPS) Server computes GNSS satellite force model parameters using a plurality of GNSS satellite force models, and wherein the Predicted GPS (PGPS) Client generates predicted Orbital State Vectors (OSV) by propagating provided initial satellite position and velocity provided by said Predicted GPS (PGPS) Server using GNSS satellite force model parameters from one or more of available ones of said GNSS satellite force models provided by said Predicted GPS (PGPS) server.

64. The method of claim 54, wherein real-time satellite integrity information received from said GRN Server is provided to the Predicted GPS (PGPS) Client as a change to the initial satellite position and velocity and to the GNSS satellite force model parameters from previously delivered initial satellite position and velocity and GNSS satellite force model parameters, such that when there are satellite integrity events that cause the said initial satellite position and velocity and the said initial GNSS satellite force model parameters to be invalid, an update can be provided without requiring new parameters for said initial satellite position and velocity and said initial GNSS satellite force model parameters to be provided to the said Predicted OPS (PGPS) Client.

65. A real-time Assisted-GPS and distributed GPS or GNSS method of orbit modeling and propagation, comprising:

(a) computing GNSS satellite force model parameters using a Predicted GPS (PGPS) Server;

(b) providing real-time GPS assistance data using a Global Reference Network (GRN) Server;

(c) selectively delivering said real-time GPS assistance data and/or said GNSS satellite force model parameters and a plurality of GNSS satellite position and velocity Orbital State Vectors (OSV'"'"'s) to a Predicted GPS (PGPS) Client via a communications link;

(d) generating within said Predicted GPS (PGPS) Client a predicted Orbital State Vector (OSV) comprising a satellite position and velocity, by propagating the initial satellite position and velocity provided by said Predicted GPS (PGPS) Server to a different time than the time of said initial satellite position and velocity, using said GNSS satellite force model parameters provided by said Predicted GPS (PGPS) server to said Predicted GPS (PGPS) Client; and

(e) providing a local GPS or AGPS device with predicted assistance data derived from said predicted Orbital State Vector (OSV) when no real-time network connection is available, or providing a local GPS or AGPS device with either real-time GPS assistance data, or predicted assistance data derived from said predicted Orbital State Vector (OSV) when a real-time network connection is available;

wherein said predicted assistance data is derived by converting said predicted Orbital State Vector (OSV) into the so-called satellite navigation data model format and provided by said Predicted GPS (PGPS) Client to said GPS or AGPS device at a time and in a format required by said GPS or AGPS device;

and wherein said real-time assistance data is provided by said Predicted GPS (PGPS) Client to said GPS or AGPS device at a time and in a format required by said GPS or AGPS device.

66. A real-time Assisted-GPS and distributed GPS or GNSS method of orbit modeling and propagation, comprising:

(a) computing GNSS satellite force model parameters using a Predicted GPS (PGPS) Server;

(b) providing real-time GPS assistance data using a Global Reference Network (GRN) Server;

(c) selectively delivering said real-time GPS assistance data and/or said GNSS satellite force model parameters and a plurality of GNSS satellite position and velocity Orbital State Vectors (OSV'"'"'s) to a Predicted GPS (PGPS) Client via a communications link;

(d) generating within said Predicted GPS (PGPS) Client a predicted Orbital State Vector (OSV) comprising a satellite position and velocity, by propagating the initial satellite position and velocity provided by said Predicted GPS (PGPS) Server to a different time than the time of said initial satellite position and velocity, using said GNSS satellite force model parameters provided by said Predicted GPS (PGPS) server to said Predicted GPS (PGPS) Client; and

(e) providing a local GPS or AGPS device with predicted assistance data derived from said predicted Orbital State Vector (OSV) when no realtime network connection is available, or providing a local GPS or AGPS device with either realtime GPS assistance data, or predicted assistance data derived from said predicted Orbital State Vector (OSV) when a real-time network connection is available;

wherein said predicted assistance data consists of the satellite position and velocity contained in said predicted Orbital State Vector (OSV) without converting into the so-called satellite navigation data model format and provided by said Predicted GPS (PGPS) Client to said GPS or AGPS device at a time and in a format required by said GPS or AGPS device.

and wherein said real-time assistance data is provided by said Predicted GPS (PGPS) Client to said GPS or AGPS device at a time and in a format required by said GPS or AGPS device.