Satellite system with different frequency plan at the equator
A non-geostationary satellite is configured to provide a plurality of spot beams that implement a first frequency plan at Earth's Equator and a second frequency plan away from Earth's Equator. The second frequency plan is different than the first frequency plan. In one embodiment, the non-geostationary satellite is part of a constellation of non-geostationary satellites, with each of the satellites providing spot beams that implement a first frequency plan at Earth's Equator and implement a second frequency plan away from Earth's Equator as the satellites travel in orbit around Earth.
1. A satellite communication system, comprising:
a non-geostationary satellite configured to provide a plurality of spot beams that implement a first frequency plan for at least two of the spot beams that are planned to illuminate at Earth's Equator and a second frequency plan for at least two other spot beams that are planned to illuminate Earth elsewhere than Earth's Equator, where the second frequency plan is different than the first frequency plan.
2. The satellite communication system of claim 1 , wherein:
the Earth illuminating plans of the satellite include a first subset of two or more rows of spot beams configured to illuminate a first region that overlaps Earth's Equator and a second subset of two or more rows of spot beams configured to illuminate a second region that does not overlap the Equator, where the first subset of spot beams implement the first frequency plan, the second subset of spot beams implement the second frequency plan.
3. The satellite communication system of claim 1 , wherein:
the first frequency plan specifies frequency bands that are allowed to be used and frequency bands that are not allowed to be used by beams implementing the first frequency plan; and
the second frequency plan specifies frequency bands are allowed to be used and frequency bands are not allowed to be used by beams implementing the second frequency plan.
4. The satellite communication system of claim 3 , wherein:
the second frequency plan allows use of frequency bands not allowed to be used in the first frequency plan.
5. The satellite communication system of claim 3 , wherein:
the non-geostationary satellite has a plurality of antennas for providing the plurality of spot beams that are planned to illuminate Earth and the plurality of antennas are configured to also receive respective uplink signals from respective spots on Earth that the respective antennas can illuminate by way of their respective spot beams;
the first frequency plan allows use of different uplink frequency bands than allowed by the second frequency plan; and
the first frequency plan allows use of includes different downlink frequency bands than allowed by the second frequency plan.
6. The satellite communication system of claim 3 , wherein:
the second frequency plan allows use of larger continuous frequency ranges than does the first frequency plan.
7. The satellite communication system of claim 3 , wherein:
the second frequency plan allows use of a greater number of continuous frequency ranges than does the first frequency plan.
8. The satellite communication system of claim 3 , wherein:
the second frequency plan allows use of more bandwidth than does the first frequency plan.
9. The satellite communication system of claim 3 , wherein:
the first frequency plan specifies respective beam polarizations to be used for the respective frequency bands that are allowed to be used by beams implementing the first frequency plan; and
the second frequency plan specifies respective beam polarizations to be used for the respective frequency bands that are allowed to be used by beams implementing the second frequency plan.
10. The satellite communication system of claim 1 , wherein:
the non-geostationary satellite is configured to implement time-domain beam hopping for at least a subset of the plurality of spot beams that are non-articulated spot beams so as to compensate for movement of the non-geostationary satellite relative to Earth's surface and for potentially varying dwell time preferences or needs of surface terminals.
11. The satellite communication system of claim 10 , wherein:
the Earth illuminating plans of the satellite include a first subset of spot beams configured to illuminate a first region that is located at Earth's Equator and a second subset of spot beams configured to illuminate a second region away from the Equator;
the first subset of spot beams implement the first frequency plan;
the second subset of spot beams implement the second frequency plan;
the first subset of spot beams implement a first beam hopping plan; and
the second subset of spot beams implement a second beam hopping plan that is different than the first beam hopping plan.
12. The satellite communication system of claim 11 , wherein:
the first subset of spot beams are divided into respective subdivisions for respectively illuminating respective parts of a first set of predetermined zones on Earth's surface and into respective first beam hopping groups where each first beam hopping group has plural beams and no more than one beam thereof is planned to illuminate a corresponding part of the first set of predetermined zones;
the second subset of spot beams are divided into a second set of predetermined zones and into respective second beam hopping groups where each second beam hopping group has plural beams and at least one beam thereof is planned to illuminate a corresponding part per of the second set of predetermined zones;
the first set of zones are in a first area at the Equator; and
the second set of zones are in a second set of areas away from the Equator, the second set of areas are above and below the Equator.
13. The satellite communication system of claim 1 , further comprising:
additional satellites that together with the non-geostationary satellite form an Earth surrounding constellation of spaced apart non-geostationary satellites that each are configured to similarly implement the first frequency plan at Earth's Equator and the second frequency plan away from Earth's Equator.
14. The satellite communication system of claim 13 , wherein:
each respective satellite of the constellation has a respective same beam map; and
each satellite of the Earth surrounding constellation of spaced apart non-geostationary satellites is configured to travel along a same orbital path.
15. A satellite communication system, comprising:
a non-geostationary satellite configured to provide a plurality of spot beams that implement a first frequency plan at Earth's Equator and a second frequency plan away from Earth's Equator, the second frequency plan is different than the first frequency plan, wherein:
the satellite includes a first subset of spot beams configured to illuminate a first region that is located at Earth's Equator and a second subset of spot beams configured to illuminate a second region away from the Equator;
the first set of spot beams implement the first frequency plan;
the second set of spot beams implement the second frequency plan;
the first set of spot beams consist of only non-articulated spot beams relative to the satellite; and
the second set of spot beams includes non-articulated spot beams relative to the satellite and steerable spot beams.
16. A satellite communication system, comprising:
a constellation of non-geostationary satellites spaced apart to surround the Earth, each of the non-geostationary satellites configured to provide a plurality of spot beams that include a first subset of plural spot beams configured to illuminate within a first region that is located at Earth's Equator and a second subset of plural spot beams configured to illuminate within a second region away from the Equator and not illuminated by the first subset, the first subset of plural spot beams implement a first frequency plan, the second subset of plural spot beams implement a second frequency plan different than the first frequency plan.
17. The satellite communication system of claim 16 , wherein:
each respective satellite of the constellation has a respective same beam map; and
each satellite of the constellation is configured to travel along a same orbital path.
18. The satellite communication system of claim 16 , wherein:
each satellite of the constellation is configured to implement time-domain beam hopping for its respective plurality of spot beams that are non-articulated spot beams so as to compensate for movement of the respective non-geostationary satellite relative to Earth's surface and for potentially varying dwell time preferences or needs of surface terminals.
19. The satellite communication system of claim 18 , wherein:
the first subset of spot beams for each satellite of the constellation is configured to implement a first beam hopping plan; and
the second subset of spot beams for each satellite of the constellation is configured to implement a second beam hopping plan that is different than the first beam hopping plan.
20. The satellite communication system of claim 19 , wherein:
the first subset of spot beams for each satellite of the constellation is divided into a first set of zones and a first set of beam hopping groups that have no more than one beam per zone of the first set of zones;
the second subset of spot beams for each satellite of the constellation is divided into a second set of zones and a second set of beam hopping groups that have no more than one beam per zone of the second set of zones;
the first set of zones are in the first region; and
the second set of zones are in the second region, the second region includes areas above and below the Equator.
21. The satellite communication system of claim 16 , wherein:
the first frequency plan specifies frequency bands that are allowed to be used and frequency bands that are not allowed to be used by beams implementing the first frequency plan; and
the second frequency plan specifies frequency bands are allowed to be used and frequency bands are not allowed to be used by beams implementing the second frequency plan.
22. A method for communicating, comprising:
operating a constellation of non-geostationary satellites;
each of the satellites being operated to provide a respective plurality of spot beams that implement a first frequency plan for at least two of the spot beams of the respective satellite that are planned to illuminate at Earth's Equator and implement a different second frequency plan for at least two others of the spot beams of the respective satellite that are planned to illuminate Earth elsewhere than Earth's Equator as the satellites travel in orbit around Earth;
where said operating of the constellation of non-geostationary satellites includes having multiple satellites of the constellation communicating with a first terminal at the Equator using spot beams that implement the first frequency plan; and
having multiple satellites of the constellation communicating with a second terminal away from the Equator using spot beams that implement the second frequency plan.
23. The method of claim 22 , wherein:
the operating the constellation of non-geostationary satellites includes having each of the satellites of the constellation traveling spaced apart along a same orbital path so that the constellation surrounds the Earth; and
the communicating with the first terminal and the communicating with the second terminal includes using a respective same beam map for each respective one of the satellites of the constellation.
24. The method of claim 23 , wherein:
the communicating with the first terminal and the communicating with the second terminal includes using respective adjacent fields of regard of respective ones of the satellites of the constellation.
25. The method of claim 22 , wherein:
the communicating with the first terminal and the communicating with the second terminal includes implementing time domain beam hopping for the spot beams of each of the satellites of the constellation, the beam hopping spot beams being non-articulated spot beams such that the implemented time domain beam hopping compensates for movement of the respective non-geostationary satellites relative to Earth's surface and for potentially varying dwell time preferences or needs of surface terminals.
26. The method of claim 22 , wherein:
each of the satellites includes a first set of spot beams configured to illuminate a first region that is located at Earth's Equator and a second set of spot beams configured to illuminate a second region away from the Equator;
the first set of spot beams implement the first frequency plan;
the second set of spot beams implement the second frequency plan; and
the communicating with the first terminal and the communicating with the second terminal includes implementing a first time domain beam hopping plan for the first set of spot beams of each of the satellites of the constellation and implementing a second time domain beam hopping plan for the second set of spot beams of each of the satellites of the constellation, where the first set of spot beams and the second set of spot beams are non-articulated spot beams.
27. The method of claim 26 , wherein:
the first set of spot beams for each satellite of the constellation is divided into a first set of zones and a first set of beam hopping groups that have no more than one beam per zone of the first set of zones;
the second set of spot beams for each satellite of the constellation is divided into a second set of zones and a second set of beam hopping groups that have no more than one beam per zone of the second set of zones;
the first set of zones are in the first region; and
the second set of zones are in the second region, the second region includes areas above and below the Equator.