Satellite constellation system

• US 6,868,316 B1
• Filed: 03/21/2003
• Issued: 03/15/2005
• Est. Priority Date: 03/21/2002
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Stevens, Craig W.
• Primary Examiner(s): BEHNCKE, CHRISTINE M
• Application Number:
  US10/394,460
• Time in Patent Office: 725 Days
• Field of Search: 701/13, 244/158.R, 244/164, 244/171
• US Class Current: 701/13
• CPC Class Codes: B64G 1/1007 Communications satellites
• CPC Class Codes: B64G 1/1085 Swarms and constellations
• CPC Class Codes: B64G 1/242 Orbits and trajectories
• CPC Class Codes: B64G 1/244 Spacecraft control systems

Abstract

A satellite constellation system, including a plurality of satellites in relatively close proximity to each other so that line-of-sight communications can be maintained at all times between adjacent satellites. The satellites are in closely-spaced orbits with incremental offsets in their starting true anomalies to create a pattern of the satellites which is serpentine in nature, moving north and south through latitudes covered as a result of the selected inclination angle while moving also in a longitudinal direction so that the serpentine pattern moves across most ground regions of interest. The constellation is asymmetric in nature in order to maximize the continuous access time. It is also possible to have multiple symmetrically-located constellations of this type.

Claims

1. A constellation of satellites, comprising:

a plurality of man-made satellites that are asymmetrically located relative to a celestial body along a plurality of orbits located at a substantially common altitude and having a substantially common inclination relative to a reference circle about the celestial body, each respective satellite having a starting true anomaly that is incrementally offset from the satellite in the next adjacent orbit, each satellite being at all times within line-of-sight of the satellite in the next adjacent orbit;

wherein each of the plurality of satellites appear to follow the satellite in the next adjacent orbit to the east from a vantage point on the celestial body so that together the plurality of satellites follow a serpentine pattern over the celestial body.

2. A constellation as defined in claim 1, wherein the constellation includes between two and twelve satellites.

3. A constellation as defined in claim 2, wherein the constellation includes between four and seven satellites.

4. A constellation as defined in claim 1, wherein each satellite resides in a different orbit.

5. A constellation as defined in claim 1, wherein the particular form of the serpentine pattern is a function of the spacing between the orbits as measured by the angular spacing between an ascending node of each orbit.

6. A constellation as defined in claim 5, wherein the spacing between the orbits as measured by the angular spacing between the ascending node of each orbit is between 30 and 60 degrees.

7. A constellation as defined in claim 1, wherein each orbit is spaced apart by approximately 45 degrees.

8. A constellation as defined in claim 1, wherein the particular form of the serpentine pattern is a function of a magnitude of the incremental offsets in the starting true anomaly of each satellite.

9. A constellation as defined in claim 1, wherein a magnitude of the incremental offsets in the starting true anomaly of each satellite is between 40 and 80 degrees.

10. A constellation as defined in claim 1, wherein a magnitude of the incremental offsets in the starting true anomaly of each satellite is approximately 60 degrees.

11. A constellation as defined in claim 1, wherein there is a lead satellite, at least one intermediate satellite and a last satellite, and wherein the lead satellite remains in constant communication with the next adjacent satellite, the last satellite remains in constant communication with the previous adjacent satellite, and all intermediate satellites remain in constant communication with both the next adjacent and the previous adjacent satellites.

12. A constellation as defined in claim 1, wherein the plurality of satellites together are a first group of satellites and further including a second group of satellites similar to the first group except that the second group is displaced from the first group.

13. A constellation as defined in claim 1, wherein the orbits are prograde orbits.

14. A constellation as defined in claim 1, wherein the orbits are retrograde orbits.

15. A constellation of satellites, comprising:

a pair of sub-constellations orbiting around a celestial body, the sub-constellations being offset from each other relative to a reference circle about the celestial body, each sub-constellation including;

a plurality of man-made satellites that are asymmetrically located relative to the celestial body along a plurality of orbits located at a substantially common altitude and having a substantially common inclination relative to the reference circle, each respective satellite having a starting true anomaly that is incrementally offset from the satellite in the next adjacent orbit, each satellite being at all times within line-of-sight of the satellite in the next adjacent orbit;

wherein each of the plurality of satellites appear to follow the satellite in the next adjacent orbit to the east from a vantage point on the celestial body so that together the plurality of satellites follow a serpentine pattern over the celestial body;

wherein the pair of sub-constellations are symmetrically located relative to each other relative to the celestial body, while the total number of satellites in the pair of sub-constellations together are asymmetrically located relative to the celestial body.

16. A constellation as defined in claim 15, wherein each sub-constellation includes between two and twelve satellites.

17. A constellation as defined in claim 16, wherein each sub-constellation includes between four and seven satellites.

18. A constellation as defined in claim 15, wherein each satellite of a given sub-constellation resides in a different orbit.

19. A constellation as defined in claim 18, wherein each satellite of a given sub-constellation resides in the same orbit as a corresponding satellite in the other sub-constellation.

20. A constellation as defined in claim 15, wherein the particular form of the serpentine pattern of each sub-constellation is a function of the spacing between the orbits as measured by the angular spacing between an ascending node of each orbit.

21. A constellation as defined in claim 20, wherein the spacing between the orbits as measured by the angular spacing between an ascending node of each orbit is between 30 and 60 degrees.

22. A constellation as defined in claim 15, wherein each orbit is spaced apart by approximately 45 degrees.

23. A constellation as defined in claim 15, wherein the particular form of the serpentine pattern is a function of a magnitude of the incremental offsets in the starting true anomaly of each satellite.

24. A constellation as defined in claim 15, wherein a magnitude of the incremental offsets in the starting true anomaly of each satellite is between 40 and 80 degrees.

25. A constellation as defined in claim 15, wherein a magnitude of the incremental offsets in the starting true anomaly of each satellite is approximately 60 degrees.

26. A constellation as defined in claim 15, wherein within each sub-constellation there is a lead satellite, at least one intermediate satellite, and a last satellite, and wherein within each sub-constellation the lead satellite remains in constant communication with the next adjacent satellite, the last satellite remains in constant communication with the previous adjacent satellite, and all intermediate satellites remain in constant communication with both the next adjacent and the previous adjacent satellites.

27. A constellation as defined in claim 15, wherein the orbits are prograde orbits.

28. A constellation as defined in claim 15, wherein the orbits are retrograde orbits.

29. A constellation of satellites, comprising:

a plurality of man-made satellites that are asymmetrically located relative to a celestial body along an equal plurality of separate orbits located at a substantially common altitude and having a substantially common inclination relative to a reference circle about the celestial body, each respective satellite having a starting true anomaly that is incrementally offset from the satellite in the next adjacent orbit, each satellite being at all times within line-of-sight of the satellite in the next adjacent orbit, wherein the plurality includes between two and seven satellites;

wherein each of the plurality of satellites appear to follow the satellite in the next adjacent orbit to the east from a vantage point on the celestial body so that together the plurality of satellites follow a serpentine pattern over the celestial body, wherein the particular form of the serpentine pattern is a function of the spacing between the orbits as measured by the angular spacing between an ascending node of each orbit and a function of a magnitude of the incremental offsets in the starting true anomaly of each satellite; and

wherein the lead satellite remains in constant communication with the next adjacent satellite, the last satellite remains in constant communication with the previous adjacent satellite, and all intermediate satellites remain in constant communication with both the next adjacent and the previous adjacent satellites.

30. A constellation as defined in claim 29, wherein the plurality of satellites together are a first group of satellites and further including a second group of satellites similar to the first group except that the second group is angularly displaced from the first group as measured by the ascending nodes of the satellites in each constellation.