Satellite positioning system

• US 6,950,060 B1
• Filed: 10/15/2002
• Issued: 09/27/2005
• Est. Priority Date: 10/15/2002
• Status: Expired due to Fees

• Current Assignee: General Dynamics C4 Systems Incorporated (General Dynamics Corporation)
• Original Assignee: General Dynamics C4 Systems Incorporated (General Dynamics Corporation)
• Inventors: Klein, Dale W.
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US10/271,932
• Time in Patent Office: 1,078 Days
• Field of Search: 342/357.06, 342/358, 244/158.R, 455/12.1, 701/226, 701/224
• US Class Current: 342/358
• CPC Class Codes: B64G 1/1085 Swarms and constellations
• CPC Class Codes: B64G 1/242 Orbits and trajectories
• CPC Class Codes: G01S 19/02 Details of the space or ground control segments

Abstract

A satellite positioning system and method of maintaining the positioning and clock data of a satellite using as few as one or two monitoring stations is disclosed. Each satellite of the positioning system determines its own positioning and clock data relative to other satellites in a constellation. One or more satellite signal monitoring stations receive relative clock and positioning data from a plurality of satellites in the constellation. A constellation solution which is applicable to all of the satellites in the constellation is calculated by treating the constellation as a rigid body at a fixed point in time. The constellation solution is transmitted to a satellite of the constellation which disseminates the solution through a crosslink network within the constellation for use by each satellite to update its individual positioning and clock data as needed. Due to the stability of the position and clock measurements using the method of the present invention, satellite uploads need only occur for one satellite in a constellation once each two or more days rather than every day for every satellite as is conventionally done. The use of mobile monitoring stations and the capacity of the positioning system to assist in updating the position and clock data of satellites passing the constellation are disclosed. In particular embodiments of the invention, the satellite positioning system is configured as a global positioning system (GPS).

Claims

1. A positioning system configured to determine an orbital location of a non-geosynchronous satellite in a satellite constellation, the system comprising:

at least one satellite signal monitoring station each configured to determine constellation orientation data from a signal received from at least a first non-geosynchronous satellite of the constellation;

a processor configured to receive data from the at least one satellite signal monitoring station in response to the constellation orientation data and to calculate constellation orientation corrections; and

a transmitter configured to transmit the constellation orientation corrections to at least one non-geosynchronous satellite of the constellation.

2. The positioning system of claim 1, wherein the processor is configured to calculate a constellation orientation solution applicable to all satellites in the constellation.

3. The positioning system of claim 1, wherein each satellite in the constellation is configured to determine its position relative to at least one other satellite in the constellation and transmit its relative position to a satellite signal monitoring station.

4. The positioning system of claim 1, wherein each satellite signal monitoring station is configured to receive relative position data from a plurality of satellites in the constellation.

5. The positioning system of claim 1, wherein the at least a first satellite and the at least one satellite of the constellation are the same satellite.

6. The positioning system of claim 1, wherein the at least one satellite signal monitoring station comprises only two satellite signal monitoring stations.

7. The positioning system of claim 1, wherein at least one of the satellite signal monitoring stations is a mobile satellite signal monitoring station.

8. The positioning system of claim 1, wherein the system is further configured to monitor relative time offsets for the constellation satellites and transmit a time offset solution applicable to all satellites in the constellation.

9. The positioning system of claim 1, wherein the positioning system is a GPS system, the satellite is a GPS satellite, the satellite constellation is a constellation of GPS satellites and the at least one satellite signal monitoring station is a GPS signal monitoring station.

10. A method of determining an orbital location of a non-geosynchronous satellite in a constellation, the method comprising:

determining a location of a first non-geosynchronous satellite in the constellation relative to a second non-geosynchronous satellite in the constellation;

determining an orientation of the constellation relative to a reference after determining the relative locations of the first and second non-geosynchronous satellites to each other; and

transmitting constellation orientation data to at least one non-geosynchronous satellite in the constellation.

11. The method of claim 10, further comprising determining location corrections for each of the first and second satellite in response to the orientation data.

12. The method of claim 10, further comprising disseminating the orientation data to each of the satellites in the constellation.

13. The method of claim 12, further comprising disseminating the orientation data through crosslinks associated with each of the satellites in the constellation.

14. The method of claim 10, wherein determining the orientation of the constellation relative to a reference comprises determining a position vector for the first satellite in the constellation and determining a position vector for a satellite signal monitoring station receiving signals from the first satellite.

15. The method of claim 14, wherein determining the orientation of the constellation relative to a reference further comprises determining an orientation angle vector for the constellation from the position vectors of the first satellite and the satellite signal monitoring station.

16. The method of claim 15, wherein determining the orientation of the constellation relative to a reference further comprises determining an orientation angle vector for the constellation from a position vector of the second satellite and the position vector of the satellite signal monitoring station.

17. The method of claim 16, wherein determining the orientation of the constellation relative to a reference further comprises forming a matrix of orientation angle vectors for the constellation including orientation angle vectors determined with reference to each of the first satellite and the second satellite.

18. The method of claim 10, wherein determining the location of the first satellite in the constellation relative to the second satellite in the constellation is determined without regard to any Earth-based reference.

19. The method of claim 10, wherein determining the orientation of the constellation relative to a reference comprises determining the orientation using only two satellite signal monitoring stations.

20. The method of claim 10, wherein determining the orientation of the constellation relative to a reference comprises determining the orientation using only one satellite signal monitoring station.

21. The method of claim 10, wherein determining the orientation of the constellation relative to a reference comprises determining the orientation using at least one mobile satellite signal monitoring station.

22. The method of claim 10, wherein the satellite in a satellite constellation is a GPS satellite in a GPS constellation.

23. The method of claim 10, further comprising determining a satellite clocks relative to each other, determining a mean clock offset, and transmitting time offset data with the orientation data.

24. A method of determining an orbital location of a satellite, the method comprising:

determining position and clock data of the satellite in relation to position and clock data of other satellites in a constellation of satellites;

determining a mean clock offset for the constellation and an orientation of the constellation relative to Earth; and

transmitting constellation orientation data and time offset data to a satellite in the constellation of satellites.

25. The method of claim 24, wherein the constellation orientation data and time offset data comprise a constellation solution applicable to all satellites in the constellation.

26. The method of claim 25, further comprising transmitting the constellation solution to all satellites in the constellation.

27. The method of claim 26, wherein transmitting the constellation solution to all satellites comprises transmitting the constellation solution from a satellite to another satellite through a crosslink.

28. The method of claim 25, further comprising adjusting at least one of a satellite'"'"'s position and clock data in response to the constellation solution.

29. The method of claim 24, wherein the satellite is a GPS satellite and the constellation of satellites is a constellation of GPS satellites.

30. The method of claim 24, further comprising determining each satellite'"'"'s position and clock data relative to other satellite position and clock data in the constellation and transmitting relative position and clock data from at least one of the satellites to at least one satellite signal monitoring station.

31. The method of claim 30, further comprising receiving the relative position and clock data from a plurality of satellites in the constellation at the satellite monitoring station.

32. The method of claim 24, further comprising monitoring the relative position and clock of a satellite at a mobile satellite signal monitoring station.

33. The method of claim 24, wherein determining the orientation of the constellation of satellites comprises determining at least one of a constellation orientation angle and an observation vector.

34. The method of claim 24, wherein determining the position of the satellite in relation to the constellation of satellites comprises determining a position vector for a first satellite in the constellation and determining a position vector for a second satellite in the constellation.

35. The method of claim 24, wherein determining an orientation of the constellation of satellites comprises determining an orientation angle vector for the constellation from a position vector for each of a satellite in the constellation and a satellite signal monitoring station.

36. The method of claim 35, wherein determining an orientation of the constellation of satellites further comprises determining the orientation angle vector for the constellation from a position vector of at least a second satellite and the position vector of the satellite signal monitoring station.

37. The method of claim 36, wherein determining the orientation of the constellation with respect to Earth further comprises forming a matrix of orientation angle vectors for the constellation including orientation angle vectors determined with reference to each of a plurality of satellites in the constellation.

38. The method of claim 24, wherein determining the orientation of the constellation comprises determining the orientation using only two satellite signal monitoring stations.

39. The method of claim 24, wherein determining the orientation of the constellation comprises determining the orientation using at least one mobile satellite signal monitoring station.

40. A method of determining an orbital location of a satellite in a constellation, the method comprising:

determining a location of a first satellite in the constellation relative to a second satellite in the constellation;

determining an orientation of the constellation relative to a reference using only two satellite signal monitoring stations; and

transmitting orientation data to a satellite in the constellation.

41. A method of determining an orbital location of a satellite in a constellation, the method comprising:

determining a location of a first satellite in the constellation relative to a second satellite in the constellation;

determining an orientation of the constellation relative to a reference using only one satellite signal monitoring station; and

transmitting orientation data to a satellite in the constellation.

42. A method of determining an orbital location of a satellite in a constellation, the method comprising:

determining a location of a first satellite in the constellation relative to a second satellite in the constellation;

determining an orientation of the constellation relative to a reference using only two satellite signal monitoring stations;

determining satellite clocks relative to each other, determining a mean clock offset, and transmitting time offset data with the orientation data; and

transmitting orientation data to a satellite in the constellation.