Apparatus and process for a global navigation satellite system meeting safety of life performance requirements

• US 7,576,691 B2
• Filed: 03/21/2007
• Issued: 08/18/2009
• Est. Priority Date: 03/22/2006
• Status: Expired due to Fees

• Current Assignee: Eads Astrium GmbH
• Original Assignee: Eads Astrium GmbH
• Inventors: Boutteau, Bertrand, Trautenberg, Hans L., Favin-Leveque, Hugues
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Liu; Harry
• Application Number:
  US11/723,704
• Publication Number:
  US 20070285310A1
• Time in Patent Office: 881 Days
• Field of Search: 34235701-35717
• US Class Current: 342/357.45
• CPC Class Codes: G01S 19/08 providing integrity information, e.g. health of satellites or quality of ephemeris data
• CPC Class Codes: G01S 19/20 Integrity monitoring, fault detection or fault isolation of space segment

Abstract

A satellite system for providing a navigation service includes a ground segment and a user segment. The ground segment provides information to enable the user segment to autonomously determine the user position performance.

Claims

1. A satellite system for providing a navigation service, said satellite system comprising:

a ground segment; and

a user segment;

wherein,

the ground segment provides information to enable the user segment to autonomously determine user position performance; and

the information comprises at least one of the parameters i) signal in space accuracy, ii) signal in space continuity, iii) signal in space static integrity, iv) signal in space dynamic integrity, v) signal in space monitoring accuracy, vi) signal in space alert limit, vii) time to alert, and viii) signal in space variation rate limit.

2. The satellite system according to claim 1, wherein the information is provided to the user segment via a broadcast process.

3. The satellite system according to claim 2, wherein the broadcast process comprises one of i) a satellite, ii) a terrestrial communication link;

and iii) a combination of satellites and terrestrial communication links for broadcasting the information to the user segment.

4. The satellite system according to claim 1, wherein the ground segment includes a signal in space continuity risk assessment that determines at least a signal in space continuity, a signal in space integrity risk assessment that determines a signal in space static integrity, and a signal in space dynamic integrity.

5. The satellite system according to claim 1, wherein the user segment comprises a user position continuity risk assessment that determines a user position continuity risk.

6. The satellite system according to claim 1, wherein user position performance comprises at least one of the parameters user position continuity risk and user position integrity risk.

7. A process for determining user position performance, including at least user position integrity risk and user position continuity risk at a particular user location, for a user of a satellite navigation service that includes a ground segment and a user segment which communicate with satellites in a satellite navigation system, said process comprising:

said ground segment determining information needed for evaluating user position performance at said particular user location;

said ground segment broadcasting said information to said user segment via a broadcast process; and

based on said information, said user segment autonomously determining current user position performance at said particular user location;

wherein,

said information determined by said ground segment comprises satellite expected performance data for each satellite in view; and

said user position performance comprises at least said user position integrity risk and said user position continuity risk;

said satellite expected performance data includes a signal in space accuracy assessment, signal in space real time monitoring, a signal in space continuity risk assessment and a signal in space integrity risk assessment for each satellite that is in view.

8. The process according to claim 7, wherein:

said signal in space continuity risk assessment determines signal in space continuity based on a history analysis and an extrapolation method; and

said signal in space integrity risk assessment determines signal in space static and dynamic integrity based on one of i) a statistical analysis of observed signal in space error ramps or brutal variations using an extrapolation method, and ii) a pseudo range measurement collected from a network of reference receivers.

9. The process according to claim 7, wherein said user position performance data includes, user position accuracy, user position continuity and user position integrity for a given point in time and space.

10. The process according to claim 8, wherein:

user position continuity risk is determined based on said signal in space continuity risk of satellites that are within view; and

user position integrity risk is determined based on at least signal in space accuracy and said signal in space integrity risk, using a statistical error model.

11. The process according to claim 7, further comprising:

if said user position performance data determined by said user segment at said particular user location satisfies preset performance requirements, said user segment determining that said satellite navigation service is available to said particular location.

12. A satellite system for providing a navigation service, said satellite system comprising a ground segment and a user segment that communicate with satellites in said satellite system, wherein:

said ground segment determines satellite expected performance data for each of said satellites that is in view;

said ground segment broadcasts said satellite expected performance data to said user segment to enable the user segment to determine user position performance, including at least user position integrity risk and user position continuity risk, for a user of the satellite navigation service;

based on said satellite expected performance data, said user segment autonomously determines user position performance for said user segment at a particular time and user location;

if said user position performance determined by said user segment satisfies preset performance requirements, said user segment determines that said satellite navigation service is available at said particular location; and

said satellite expected performance data includes a signal in space accuracy assessment, signal in space real time monitoring, a signal in space continuity risk assessment and a signal in space integrity risk assessment for each satellite in view.

13. The process according to claim 12, wherein:

said signal in space continuity risk assessment determines signal in space continuity based on a history analysis and an extrapolation method; and

said signal in space integrity risk assessment determines signal in space static and dynamic integrity based on one of i) a statistical analysis of observed signal in space error ramps or brutal variations using an extrapolation method, and ii) a pseudo range measurement collected from a network of reference receivers.

14. The process according to claim 12, wherein said user position performance data includes user position accuracy, user position continuity and user position integrity for a given point in time and space.

15. The process according to claim 13, wherein:

user position continuity risk is determined based on said signal in space continuity risk of satellites that are within view; and

user position integrity risk is determined based on at least signal in space accuracy and said signal in space integrity risk, using to a statistical error model.

16. The satellite system according to claim 12, wherein the broadcast process comprises one of i) a satellite, ii) a terrestrial communication link;

and iii) a combination of satellites and terrestrial communication links for broadcasting the information to the user segment.

17. The satellite system according to claim 12, wherein the ground segment determines a signal in space continuity risk and a signal in space integrity risk, including a signal in space static integrity risk, and a signal in space dynamic integrity risk.

18. The satellite system according to claim 12, where the satellite expected performance data comprises at least one of the parameters i) signal in space accuracy, ii) signal in space continuity, iii) signal in space static integrity, iv) signal in space dynamic integrity, v) signal in space monitoring accuracy, vi) signal in space alert limit, vii) time to alert, and viii) signal in space variation rate limit.