Coordinatable system of inclined eccentric geosynchronous orbits

• US 6,126,116 A
• Filed: 07/21/1998
• Issued: 10/03/2000
• Est. Priority Date: 06/16/1997
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (AT&T, Inc.)
• Original Assignee: Hughes Electronics Corporation (AT&T, Inc.)
• Inventors: Cellier, Alfred
• Primary Examiner(s): Poon, Peter M.
• Assistant Examiner(s): DINH, TIEN QUANG
• Application Number:
  US09/119,680
• Time in Patent Office: 805 Days
• Field of Search: 244/158 R, 455/12.1, 455/13.1, 455/13.2, 455/13.3, 342/356
• US Class Current: 244/158.4
• 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 1/2425 Geosynchronous orbits
• CPC Class Codes: H04B 7/19 Earth-synchronous stations
• CPC Class Codes: H04B 7/195 Non-synchronous stations

Abstract

A coordinatable system of geosynchronous ("24 hour"), inclined, and slightly elliptic satellite orbits, increases available satellite orbital capacity and enables spectrum re-use by forming "highways" of moving "slots" in the space in and about the geostationary orbit (GSO) belt worldwide. Each of a plurality of repeating ground tracks is shared by multiple satellite orbits (and thus "slots"), positioned to achieve specified minimum specified angular separation from other slots using the same frequencies. Ground tracks are located at specified longitudes of symmetry, and orbital parameters are chosen to realize certain which provide the near-maximum total number of slots and which fit neatly within, and replace, some of the existing grid of GSO slots. Incremental modularity permits gradual expansion from current GSO usage, while systematic extension results in large theoretical capacity expansion.

Claims

1. A system of inclined eccentric geosynchronous satellite orbits coordinatable with a geostationary belt of satellite positions having a plurality of geostationary slots, said system comprising:

a plurality of satellite positions representing the maximum number of satellites that may be included in the coordinatable system of inclined eccentric geosynchronous satellite orbits to achieve optimum satellite coverage continuously within a specified service area;

each satellite position being located in one of a plurality of satellite orbits forming one of a plurality of families of satellite orbits;

each of the plurality of satellite orbits within any one of the plurality of families of satellite orbits defining an orbital plane having a unique inclination with respect to the equatorial plane of the Earth and with respect to the orbital plane of any other one of the plurality of satellite orbits within the same family of satellite orbits, the satellite orbits intersecting the geostationary belt;

loci of subsatellite points repeatedly traced upon the surface of the Earth by a straight line extending from the center of the Earth to an orbiting satellite position generating an imaginary ground track on the surface of the Earth;

the ground track traced by orbiting satellite positions within any one of the plurality of families of satellite orbits defining an area therewithin that differs from the area defined within the ground track traced by orbiting satellite positions within any other family of satellite orbits;

the ground tracks being mutually and generally symmetrically nested about a first longitude of symmetry to form a first set of ground tracks; and

the satellite positions within each of the plurality of families of satellite orbits being coordinated with each other and being further coordinated with the satellite positions to achieve a specified angular separation between said ground tracks of said satellites occupying the plurality of satellite positions.

2. A system as recited in claim 1, wherein the satellite orbits displace a pair of existing geostationary slots.

3. A system as recited in claim 1, wherein the ground tracks are substantially circular.

4. A system as recited in claim 1, wherein said angular separation is two degrees.

5. A system as recited in claim 1, wherein said ground tracks have a center corresponding to one of said geostationary slots.

6. A system as recited in claim 1, wherein the satellites in each of the plurality of families of satellite orbits are coordinated so that they are equally spaced in time in said ground track.

7. A system as recited in claim 1, further including a plurality of additional satellite positions to generate at least a second set of ground tracks disposed at at least a second longitude of symmetry.

8. A system of inclined eccentric geosynchronous satellite orbits coordinatable with a geostationary belt of satellite positions having a plurality of geostationary slots, said system comprising:

a plurality of satellite positions representing the maximum number of satellites that may be included in the coordinatable system of inclined eccentric geosynchronous satellite orbits to achieve optimum satellite coverage continuously within a specified service area;

each satellite position being located in one of a plurality of satellite orbits forming one of a plurality of families of satellite orbits;

each of the plurality of satellite orbits within any one of the plurality of families of satellite orbits defining an orbital plane having a unique inclination with respect to the equatorial plane of the Earth and with respect to the orbital plane of any other one of the plurality of satellite orbits within the same family of satellite orbits, the satellite orbits intersecting the geostationary belts;

the plurality of satellite orbits within any one of the plurality of families of satellite orbits having identical apogees;

loci of subsatellite points repeatedly traced upon the surface of the Earth by a straight line extending from the center of the Earth to an orbiting satellite position generating an imaginary ground track on the surface of the Earth;

the ground track traced by orbiting satellite positions within any one of the plurality of families of satellite orbits defining an area therewithin that differs from the area defined within the ground track traced by orbiting satellite positions within any other family of satellite orbits;

the ground tracks being mutually and generally symmetrically nested about one of said geostationary slots to form a first set of ground tracks;

the ground tracks having a predetermined spacing; and

the satellite positions within each of the plurality of families of satellite orbits being coordinated with each other and being further coordinated with the satellite positions to achieve a minimum specified angular between said ground tracks of said satellites occupying the plurality of satellite positions.

9. A system as recited in claim 8, wherein said predetermined spacing corresponds to a spacing of the geostationary slots.

10. A system as recited in claim 8, wherein said predetermined spacing is two degrees.

11. A system as recited in claim 8, wherein said ground tracks have a center corresponding to the geostationary slots.

12. A system as recited in claim 8, wherein each of the plurality of satellite orbits is configured to position the maximum latitude of the ground track tracked by orbiting satellite positions within each family of satellite orbits at a specified longitude.

13. A system as recited in claim 8, wherein the satellites in each of the plurality of families of satellite orbits are coordinated so that they are equally spaced in time.

14. A system as recited in claim 8, further including a plurality of additional satellite positions to generate at least a second set of ground tracks disposed at at least a second longitude of symmetry.

15. A method of providing a system of inclined eccentric geosynchronous satellite orbits coordinatable with a geostationary belt of satellite positions having a plurality of geostationary slots, the method comprising:

specifying at least one geographic service within which satellite coverage is to be provided;

defining a plurality of families of satellite orbits, each satellite orbit defining the path of a satellite position, each satellite orbit in each of the pluralities of families of satellite orbits defining an orbital plane having a unique inclination with respect to the equatorial plane of the Earth, each of the orbits intersecting a geostationary belt, loci of subsatellite points repeatedly traced upon the surface of the Earth by a straight line extending from the center of the Earth to an orbiting satellite position generating an imaginary ground track on the surface of the Earth, the ground track traced by orbiting satellite positions within any one of the plurality of families of satellite orbits defining an area therewithin that differs from the area defined within the ground track traced by orbiting satellite positions within any other family of satellite orbits;

configuring each satellite orbit in each of the plurality of families of satellite orbits so that the ground tracks are mutually and generally symmetrically nested about a first longitude of symmetry to form a first set of ground tracks;

determining a maximum number of satellites, and thus of satellite orbits, that may be included in each of the plurality of families of satellite orbits and determining the shape and geographic position of each ground track to achieve a minimum specified angular separation between satellite positions using the same frequencies and to achieve optimum satellite coverage continuously during the specified period in the at least one service area specified; and

coordinating the position of satellites in satellite orbits in accordance with the determined maximum number of satellite positions and the minimum specified angular separation therebetween.

16. A method as recited in claim 15, wherein the step of defining a plurality of families of satellite orbits, each orbit defining the path of a satellite position, further includes defining a center of the ground tracks as one of said plurality of geostationary slots.

17. A method as recited in claim 15, wherein the step of defining a plurality of families of satellite orbits, each orbit defining the path of a satellite position, further includes defining a spacing between ground tracks corresponding to a spacing of the geostationary slots.

18. A method as recited in claim 15, following the step of determining a maximum number of satellites, further including the step of configuring each of the plurality of satellite orbits to position the maximum latitude of the ground track traced by orbiting satellite positions within each family of satellite orbits at a specified longitude.

19. A method as recited in claim 15, wherein the step of coordinating the placement of satellites in satellite orbits further includes phasing the satellites in each of the families of satellite orbits so that they are equally spaced in time.

20. A method as recited in claim 15, following the step of configuring each to the plurality of satellite orbits to position the maximum latitude of the ground track traced by orbiting satellite positions within each family of satellite orbits at a specified longitude, further including the step of including additional satellite positions to generate at least a second set of ground tracks disposed at at least a second longitude of symmetry.