SATELLITE COMMUNICATIONS SYSTEMS AND METHODS USING SUBSTANTIALLY CO-LOCATED FEEDER LINK ANTENNAS

• US 20070037514A1
• Filed: 08/08/2006
• Published: 02/15/2007
• Est. Priority Date: 08/09/2005
• Status: Active Grant

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: ATC Technology Corporation (FedEx Corporation)
• Inventors: Karabinis, Peter
• Granted Patent: US 7,831,202 B2
• Time in Patent Office: Days
• US Class Current: 455/13.300
• CPC Class Codes: H04B 7/18521 Systems of inter linked satellites, i.e. inter satellite service for optical links between satellites H04B10/118
• CPC Class Codes: H04B 7/18532 Arrangements for managing transmission, i.e. for transporting data or a signalling message

Abstract

A satellite communications system includes a plurality of feeder link antennas, a primary satellite, and an auxiliary satellite. The feeder link antennas are substantially co-located relative to one another. The primary satellite is configured to receive information over a plurality of return service links from radioterminals, to communicate a first portion of the information over at least one return feeder link directly to a first one of the feeder link antennas, and to communicate a second portion of the information over at least one inter-satellite link. The auxiliary satellite is spaced apart from the primary satellite, and configured to receive the second portion of the information from the primary satellite via the at least one inter-satellite link, and to communicate the second portion of the information across at least one return feeder link to a second one of the feeder link antennas.

Claims

1. - A satellite communications system comprising:

a plurality of feeder link antennas that are substantially co-located therebetween;

a primary satellite that is configured to receive information from radioterminals, to communicate a first portion of the information over at least one return feeder link to a first one of the feeder link antennas, and to communicate a second portion of the information over at least one inter-satellite link; and

an auxiliary satellite that is spaced apart from the primary satellite, and configured to receive the second portion of the information from the primary satellite via the at least one inter-satellite link, and to communicate the second portion of the information over at least one return feeder link to a second one of the feeder link antennas.

2. The satellite communications system of claim 1, wherein the primary satellite uses a first set of frequencies to communicate with the first one of the feeder link antennas and the auxiliary satellite uses a second set of frequencies to communicate with the second one of the feeder link antennas, wherein the first set of frequencies and the second set of frequencies include at least one common frequency.

3. The satellite communications system of claim 1, wherein the primary satellite and the auxiliary satellite are spaced apart therebetween to provide an antenna discrimination between the primary satellite and the second one of the feeder link antennas, and to provide an antenna discrimination between the auxiliary satellite and the first one of the feeder link antennas.

4. The satellite communications system of claim 3, wherein the primary satellite and the auxiliary satellite are located in respective substantially geostationary orbits relative to Earth, and have a separation angle therebetween of about 2°

or more.

5. The satellite communications system of claim 1, wherein the auxiliary satellite is devoid of any configuration that allows the auxiliary satellite to communicate directly with radioterminals.

6. The satellite communications system of claim 1, wherein:

the first one of the feeder link antennas is configured to provide a substantially higher gain in a direction associated with the primary satellite and a substantially lower gain in a direction associated with the auxiliary satellite; and

the second one of the feeder link antennas is configured to provide a substantially higher gain in a direction associated with the auxiliary satellite and a substantially lower gain in a direction associated with the primary satellite.

7. The satellite communications system of claim 6, further comprising a plurality of auxiliary satellites configured to receive portions of the information from the primary satellite via a plurality of inter-satellite links, and to communicate the portions of the information over a plurality of return feeder links to a plurality of feeder link antennas, wherein each feeder link antenna of the plurality of feeder link antennas, is configured to provide a substantially higher gain in a direction associated with a respective auxiliary satellite and a substantially lower gain in a direction associated with an auxiliary satellite other than the respective auxiliary satellite.

8. The satellite communications system of claim 7, wherein two feeder link antennas of the plurality of feeder link antennas are separated therebetween by about 3000 meters or less.

9. The satellite communications system of claim 8, wherein two feeder link antennas of the plurality of feeder link antennas are separated therebetween by about 300 meters or less.

10. The satellite communications system of claim 9, wherein two feeder link antennas of the plurality of feeder link antennas are spaced therebetween by about 30 meters or less.

11. The satellite communications system of claim 1, wherein the primary satellite is further configured to distribute an aggregate signal associated with a plurality of return service links over at least one return feeder link of the primary satellite and over at least one return feeder link of the auxiliary satellite.

12. The satellite communications system of claim 11, further comprising a plurality of auxiliary satellites, wherein the primary satellite is further configured to distribute the aggregate signal over a return feeder link of the primary satellite and over a plurality of return feeder links associated with the auxiliary satellites.

13. The satellite communications system of claim 12, wherein the primary satellite is further configured to control a bandwidth utilization of the return feeder link of the primary satellite and to control a bandwidth utilization of the plurality of return feeder links associated with the auxiliary satellites.

14. The satellite communications system of claim 1, wherein the auxiliary satellite is further configured to communicate the second portion of the information received from the primary satellite substantially unchanged to the second one of the feeder link antennas.

15. The satellite communications system of claim 1, wherein:

the auxiliary satellite is further configured to receive forward link information over at least one forward feeder link from the second one of the feeder link antennas, and to communicate the forward link information to the primary satellite over at least one inter-satellite link; and

the primary satellite is further configured to communicate the forward link information to the radioterminals over a plurality of forward service links.

16. The satellite communications system of claim 1, wherein the primary satellite is further configured to receive first forward link information from the first one of the feeder link antennas and receive second forward link information from the second one of the feeder link antennas and to communicate the first and second forward link information to the radioterminals.

17. The satellite communications system of claim 1, further comprising a gateway processor that is configured to receive return feeder link signals from at least the first one of the feeder link antennas and the second one of the feeder link antennas, and to process the received return feeder link signals to reduce interference in at least one of the return feeder link signals.

18. The satellite communications system of claim 17, wherein the gateway processor is further configured to time align at least some of the return feeder link signals relative to one another, and to reduce interference in at least one of the return feeder link signals in response to the time aligned return feeder link signals.

19. The satellite communications system of claim 18, wherein the gateway processor is further configured to time align a return feeder link signal received from the first one of the feeder link antennas relative to a return feeder link signal received from the second one of the feeder link antennas, and to generate an interference correction signal from the time aligned return feeder link signals that is indicative of interference caused by at least one return feeder link from the primary satellite to at least one return feeder link received by the second one of the feeder link antennas.

20. The satellite communications system of claim 19, wherein the gateway processor is further configured to reduce interference in at least one return feeder link signal received from the second one of the feeder link antennas in response to the interference correction signal.

21. The satellite communications system of claim 18, wherein the gateway processor is further configured to time align a return feeder link signal received from the first one of the feeder link antennas relative to a return feeder link signal received from the second one of the feeder link antennas, and to generate an interference correction signal from the time aligned return feeder link signals that is indicative of interference caused by at least one return feeder link from the auxiliary satellite to at least one return feeder link received by the first one of the feeder link antennas.

22. A method of communicating in a satellite communications system, the method comprising:

receiving information at a primary satellite from radioterminals;

communicating a first portion of the information from the primary satellite over at least one return feeder link to a first one of a plurality of feeder link antennas;

communicating a second portion of the information from the primary satellite over at least one inter-satellite link to an auxiliary satellite that is spaced apart from the primary satellite; and

communicating the second portion of the information from the auxiliary satellite over at least one return feeder link to a second one of the feeder link antennas that is substantially co-located with the first one of the feeder link antennas.

23. The method of claim 22, further comprising using first feeder link frequencies to communicate information between the primary satellite and the first one of the feeder link antennas and second feeder link frequencies to communicate information between the auxiliary satellite and the second one of the feeder link antennas, wherein the first and second feeder link frequencies comprise at least one common frequency.

24. The method of claim 22, further comprising maintaining a distance between the primary satellite and the auxiliary satellite to provide a discrimination between the primary satellite and the second one of the feeder link antennas, and to provide a discrimination between the auxiliary satellite and the first one of the feeder link antennas.

25. The method of claim 24, further comprising maintaining the primary satellite and the auxiliary satellite in respective substantially geostationary orbits relative to Earth with about a 2°

or more separation angle therebetween.

26. The method of claim 22, wherein communicating a second portion of the information from the primary satellite over at least one inter-satellite link to an auxiliary satellite comprises communicating the second portion of the information from the primary satellite over at least one inter-satellite link to an auxiliary satellite that is devoid of any configuration that allows the auxiliary satellite to communicate directly with radioterminals

27. The method of claim 22, further comprising:

configuring the first one of the feeder link antennas to provide a substantially higher gain in a direction associated with the primary satellite and a substantially lower gain in a direction associated with the auxiliary satellite; and

configuring the second one of the feeder link antennas to provide a substantially higher gain in a direction associated with the auxiliary satellite and a substantially lower gain in a direction associated with the primary satellite.

28. The method of claim 27, further comprising:

communicating portions of the information received at the primary satellite from radioterminals over a plurality of the inter-satellite links to a plurality of auxiliary satellites;

communicating the portions of the information over a plurality of return feeder links from the plurality of auxiliary satellites to a respective plurality of feeder link antennas that are substantially co-located therebetween; and

configuring each feeder link antenna of the plurality of feeder link antennas to provide a substantially higher gain in a direction associated with a respective auxiliary satellite and to provide a substantially lower gain in a direction associated with an auxiliary satellite other than the respective auxiliary satellite.

29. The method of claim 22, further comprising distributing an aggregate signal associated with a plurality of return service links over the at least one return feeder link of the primary satellite and over the at least one return feeder link of the auxiliary satellite.

30. The method of claim 29, further comprising distributing the aggregate signal over the at least one return feeder link of the primary satellite and over a plurality of return feeder links associated with a plurality of auxiliary satellites.

31. The method of claim 30, further comprising controlling a bandwidth utilization of the at least one return feeder link of the primary satellite and controlling a bandwidth utilization of the plurality of return feeder links of the auxiliary satellites.

32. The method of claim 22, wherein communicating the second portion of the information from the auxiliary satellite over at least one return feeder link to a second one of the feeder link antennas that is substantially co-located with the first one of the feeder link antennas comprises:

communicating the second portion of the information received by the auxiliary satellite from the primary satellite substantially unchanged to the second one of the feeder link antennas.

33. The method of claim 22, further comprising:

receiving forward link information at the auxiliary satellite through at least one forward feeder link from the second one of the feeder link antennas;

communicating the forward link information over at least one inter-satellite link to the primary satellite; and

communicating the forward link information from the primary satellite to the radioterminals over a plurality of forward service links.

34. The method of claim 22, further comprising:

receiving at the primary satellite first forward link information from the first one of the feeder link antennas;

receiving at the primary satellite second forward link information from the second one of the feeder link antennas; and

communicating the first and second forward link information from the primary satellite to the radioterminals.

35. The method of claim 22, further comprising:

receiving return feeder link signals at a gateway processor from at least the first one of the feeder link antennas and the second one of the feeder link antennas; and

processing the received return feeder link signals at the gateway processor to reduce interference in at least one of the return feeder link signals.

36. The method of claim 35, further comprising:

time aligning at least some of the return feeder link signals relative to one another; and

reducing interference in at least one of the return feeder link signals in response to the time aligned return feeder link signals.

37. The method of claim 36, wherein time aligning at least some of the return feeder link signals relative to one another comprises:

time aligning at least one return feeder link signal received from the first one of the feeder link antennas relative to at least one return feeder link signal received from the second one of the feeder link antennas; and

generating an interference correction signal from the time aligned return feeder link signals that is indicative of interference caused by the at least one return feeder link from the primary satellite to the at least one return feeder link received by the second one of the feeder link antennas.

38. The method of claim 37, wherein processing the received return feeder link signals at the gateway processor to reduce interference in at least one of the return feeder link signals comprises:

reducing interference in the at least one received return feeder link signal from the second one of the feeder link antennas in response to the interference correction signal.

39. The method of claim 36, wherein time aligning at least some of the received return feeder link signals relative to one another comprises:

time aligning the at least one return feeder link signal provided by the first one of the feeder link antennas relative to the at least one return feeder link signal provided by the second one of the feeder link antennas; and

generating an interference correction signal from the time aligned return feeder link signals that is indicative of interference caused by the at least one return feeder link from the auxiliary satellite to the at least one return feeder link received by the first one of the feeder link antennas.

40. A primary satellite comprising:

a return service link receiver that is configured to receive information over a plurality of return service links from radioterminals;

an information spreader that is configured to distribute the information into at least first and second portions;

a feeder link transmitter that is configured to transmit the first portion of the information over at least one return feeder link directly to a first one of a plurality of feeder link antennas; and

an inter-satellite link transmitter that is configured to transmit the second portion of the information over at least one inter-satellite link to an auxiliary satellite for transmission over at least one return feeder link to a second one of the feeder link antennas that is substantially co-located relative to the first one of the feeder link antennas.

41. The primary satellite of claim 40, wherein the information spreader is further configured to distribute an aggregate signal associated with the return service links over the at least one return feeder link from the feeder link transmitter to the first one of the feeder link antennas and over the at least one inter-satellite link from the inter-satellite link transmitter to the auxiliary satellite and, therethrough, over the at least one return feeder link from the auxiliary satellite to the second one of the feeder link antennas.

42. The primary satellite of claim 40, further comprising:

a feeder link receiver that is configured to receive forward link information directly from the first one of the feeder link antennas over at least one forward feeder link;

an inter-satellite link receiver that is configured to receive forward link information over the at least one inter-satellite link from the second one of the feeder link antennas indirectly via the auxiliary satellite; and

a forward service link transmitter that is configured to transmit an aggregate forward link information over a plurality of forward service links to the radioterminals.

43. The primary satellite of claim 42, further comprising an information combiner configured to aggregate a signal associated with at least one forward feeder link from the first one of the feeder link antennas with a signal associated with at least one inter-satellite link from the auxiliary satellite.

44. The primary satellite of claim 40, wherein the feeder link transmitter is configured to transmit the information to the first one of the feeder link antennas using at least some of the same frequencies as are used by the auxiliary satellite to transmit to the second one of the feeder link antennas.

45. An auxiliary satellite comprising:

an inter-satellite link receiver that is configured to receive information from radioterminals via a primary satellite over at least one inter-satellite link; and

a feeder link transmitter that is configured to transmit the information over at least one return feeder link directly to a first one of a plurality of feeder link antennas that is substantially co-located relative to a second one of the feeder link antennas that the primary satellite transmits to over at least one return feeder link.

46. The auxiliary satellite of claim 45, wherein the feeder link transmitter is configured to transmit the information to the first one of the feeder link antennas using at least some of the same frequencies as are used by the primary satellite to transmit to the second one of the feeder link antennas.

47. The auxiliary satellite of claim 45, further comprising:

a feeder link receiver that is configured to receive forward link information directly from the first one of the feeder link antennas over at least one forward feeder link; and

an inter-satellite link transmitter that is configured to transmit the forward link information over at least one inter-satellite link to the primary satellite for transmission over a plurality of forward service links to the plurality of radioterminals.

48. Satellite communications equipment comprising:

a plurality of feeder link antennas that are substantially co-located therebetween and configured to transmit and/or receive information over feeder links to a primary satellite and at least one auxiliary satellite, wherein a first one of the feeder link antennas is configured to provide a substantially higher gain in a direction associated with the primary satellite and a substantially lower gain a direction associated with the at least one auxiliary satellite, and a second one of the feeder link antennas is configured to provide a substantially higher gain in a direction associated with one of the at least one auxiliary satellite and a substantially lower gain in a direction associated with the primary satellite; and

a gateway processor that is configured to distribute information that is directed to a plurality of radioterminals over at least one forward feeder link to the primary satellite and over at least one forward feeder link to the at least one auxiliary satellite for subsequent aggregation of the information at the primary satellite and retransmission of the information by the primary satellite to the radioterminals.

49. The satellite communications equipment of claim 48, wherein the first one of the feeder link antennas and second one of the feeder link antennas are each configured to use at least some common frequencies to communicate with the primary satellite and the at least one auxiliary satellite.

50. The satellite communications equipment of claim 48, wherein the first one of the feeder link antennas and second one of the feeder link antennas are configured to provide maximum gain in respective directions associated with the primary satellite and the at least one auxiliary satellite.

51. The satellite communications equipment of claim 48, wherein two feeder link antennas of the plurality of feeder link antennas are separated therebetween by about 3000 meters or less.

52. The satellite communications equipment of claim 51, wherein two feeder link antennas of the plurality of feeder link antennas are separated therebetween by about 300 meters or less.

53. The satellite communications equipment of claim 52, wherein two feeder link antennas of the plurality of feeder link antennas are separated therebetween by about 30 meters or less.

54. The satellite communications equipment of claim 48, wherein the gateway processor is further configured to receive return feeder link signals from the first one of the feeder link antennas and the second one of the feeder link antennas, and to process the received return feeder link signals to reduce interference in at least one of the return feeder link signals.

55. The satellite communications equipment of claim 54, wherein the gateway processor is further configured to time align at least some of the received return feeder link signals relative to one another prior to reducing interference in at least one of the return feeder link signals.

56. The satellite communications equipment of claim 55, wherein the gateway processor is further configured to generate an interference correction signal and to reduce interference in at least one return feeder link signal in response to the interference correction signal.

57. The auxiliary satellite of claim 55, wherein the auxiliary satellite is devoid of any configuration that allows the auxiliary satellite to communicate directly with radioterminals.