Fixed satellite constellation system employing non-geostationary satellites in sub-geosynchronous elliptical orbits with common ground tracks
First Claim
1. A constellation of satellites, comprising:
- a first plurality of satellites in orbits around the earth having apogees and perigees, each of the first plurality of satellites being configured to be active only during a predetermined portion of the satellite'"'"'s orbit proximate to apogee, the orbits of the first plurality of satellites having a first argument of perigee and being configured to form a first common ground track, the first common ground track repeating daily and having a number of first active arcs each corresponding to the predetermined portion of each satellite'"'"'s orbit during which the satellite is active, the orbits of the first plurality of satellites being further configured such that each one of the first active arcs begins and ends at points on a same meridian of longitude; and
a second plurality of satellites in orbits around the earth having apogees and perigees, each of the second plurality of satellites configured to be active only during a predetermined portion of the satellite'"'"'s orbit proximate to apogee, the orbits of the second plurality of satellites having a second argument of perigee being a supplementary angle to the first argument of perigee, and being configured to form a second common ground track, the second common ground track repeating daily and having a number of active arcs corresponding to the predetermined portion of each satellite'"'"'s orbit during which the satellite is active, the orbits of the second plurality of satellites being further configured such that each of the second active arcs begins at a point coincident with the ending point of one of the first active arcs, and ends at a point coincident with the beginning point of the same one of the first active arcs.
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Abstract
Provided is a system and method for implementing a constellation of satellites in inclined elliptical orbits that provides simplified satellite tracking for ground stations on the earth. The satellite orbits form a pair of repeating ground tracks around the earth. In each ground track the satellites operate only in active arcs well above or below the equator) emulating many of the characteristics of geostationary satellites. The parameters of the satellite orbits are adjusted so that the end points of the active arcs in the two ground tracks coincide; the turn-off point of an active arc in one ground track being the same as the turn-on point of an active arc in the other. For a ground station served by the satellites in these arcs, the active satellites appear to be moving slowly in one direction around a closed, teardrop-shaped path in the sky, at a generally high elevation angle.
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Citations
39 Claims
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1. A constellation of satellites, comprising:
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a first plurality of satellites in orbits around the earth having apogees and perigees, each of the first plurality of satellites being configured to be active only during a predetermined portion of the satellite'"'"'s orbit proximate to apogee, the orbits of the first plurality of satellites having a first argument of perigee and being configured to form a first common ground track, the first common ground track repeating daily and having a number of first active arcs each corresponding to the predetermined portion of each satellite'"'"'s orbit during which the satellite is active, the orbits of the first plurality of satellites being further configured such that each one of the first active arcs begins and ends at points on a same meridian of longitude; and
a second plurality of satellites in orbits around the earth having apogees and perigees, each of the second plurality of satellites configured to be active only during a predetermined portion of the satellite'"'"'s orbit proximate to apogee, the orbits of the second plurality of satellites having a second argument of perigee being a supplementary angle to the first argument of perigee, and being configured to form a second common ground track, the second common ground track repeating daily and having a number of active arcs corresponding to the predetermined portion of each satellite'"'"'s orbit during which the satellite is active, the orbits of the second plurality of satellites being further configured such that each of the second active arcs begins at a point coincident with the ending point of one of the first active arcs, and ends at a point coincident with the beginning point of the same one of the first active arcs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A satellite communications system, comprising:
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a plurality of satellites in orbits around the earth having apogees and perigees, each of the satellites having communications equipment thereon configured to communicate only during a predetermined portion of the satellite'"'"'s orbit proximate to apogee, the orbits of the first plurality of satellites having a first argument of perigee and being configured to form a first common ground track, the first common ground track repeating daily and having a number of first active arcs each corresponding to the predetermined portion of each satellite'"'"'s orbit during which the communications equipment on the satellite is configured to communicate, the orbits of the first plurality of satellites being further configured such that each one of the first active arcs begins and ends at points on a same meridian of longitude;
a second plurality of satellites in orbits around the earth having apogees and perigees, each of the second plurality of satellites having communication equipment thereon configured to be communicate only during a predetermined portion of the satellite'"'"'s orbit proximate to apogee, the orbits of the second plurality of satellites having a second argument of perigee being a supplementary angle to the first argument of perigee, and being configured to form a second common ground track, the second common ground track repeating daily and having a number of active arcs corresponding to the predetermined portion of each satellite'"'"'s orbit during which the communications equipment on the satellite is configured to communicate, the orbits of the second plurality of satellites being further configured such that each of the second active arcs begins at a point coincident with the ending point of one of the first active arcs, and ends at a point coincident with the beginning point of the same one of the first active arcs; and
a plurality of ground stations, each having communications equipment configured to communicate with the communications equipment on each of the first and second pluralities of satellites, and each located at a position on the earth from which it can track satellites in one of the first active arcs and satellites in the one of the second active arcs have coincident beginning and ending points. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method for satellite communications, comprising:
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orbiting a first and a second plurality of communications satellites about the earth, the orbits having apogees and perigees; and
enabling each satellite of the first and second pluralities of communications satellites to communicate only during a predetermined portion of its orbit proximate to apogee;
wherein the orbits of the first plurality satellites have a first argument of perigee and form a first common ground track on the earth, the first common ground track repeating daily and having a number of first active arcs, each first active arc corresponding to the portion of the orbit of each satellite during which the communications equipment on the satellite is enabled to communicate;
wherein the orbits of the second plurality satellites have a second argument of perigee being a supplementary angle to the first argument of perigee, and form a second common ground track on the earth, the second common ground track repeating daily and having a number of second active arcs, each second active arc corresponding to the portion of the orbit of each satellite during which the communications equipment on the satellite is enabled to communicate;
wherein the first plurality of satellites are orbited such that each on of the first active arcs begins and ends at points on a same meridian of longitude; and
wherein the second plurality of satellites are orbited such that each of the second active arcs begins at a point coincident with the ending point of one of the first active arcs, and ends at a point coincident with the beginning point of the same one of the first active arcs. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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Specification