Tetrahedral multi-satellite continuous-coverage constellation
First Claim
1. A communication system comprising a constellation of inclined elliptic artificial satellites orbiting earth for providing continuous global line-of-sight visibility and having communication means for providing communication via the means of at least one satellite at all times with all points on the earth ;
- said constellation comprising four common-period elliptic-orbit satellites, said satellites having orbital parameters of period, inclination angle, eccentricity, right ascension of ascending nodes, arguments of perigee, and mean anomaly relationship, two of said satellites having perigees in one hemisphere and the other two of said satellites having perigees in the other hemisphere, said satellites continuously defining a tetrahedron which completely encloses the earth and whose planes do not intersect the earth'"'"'s surface so as to assure said continuous visibility.
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Abstract
An improved, optimized, four-satellite tetrahedral constellation using common period elliptic orbits is disclosed which provides continuous global coverage (i.e., any point on the earth can always maintain line-of-sight visibilty with at least one of the four satellites). The constellation consists of two satellites having perigees in one hemisphere, and two satellites having perigees in the other hemisphere. All satellites have a common period, and positive visibility angles can be maintained down to a constellation (or satellite) period of 27 hours. At higher altitudes (longer periods) both the minimum visibility angles and the mean visibility angles will tend to increase. Replication may be provided by overlaying arrays with convenient offset. The invention is applicable to any celestial body wherein two satellites have two periapses in one hemisphere and the other two satellites have periapses in the other hemisphere.
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Citations
14 Claims
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1. A communication system comprising a constellation of inclined elliptic artificial satellites orbiting earth for providing continuous global line-of-sight visibility and having communication means for providing communication via the means of at least one satellite at all times with all points on the earth ;
- said constellation comprising four common-period elliptic-orbit satellites, said satellites having orbital parameters of period, inclination angle, eccentricity, right ascension of ascending nodes, arguments of perigee, and mean anomaly relationship, two of said satellites having perigees in one hemisphere and the other two of said satellites having perigees in the other hemisphere, said satellites continuously defining a tetrahedron which completely encloses the earth and whose planes do not intersect the earth'"'"'s surface so as to assure said continuous visibility.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A communication system comprising a constellation of artificial satellites orbiting a celestial body for providing continuous line-of-sight visibility and having communication means for providing communication via the means of at least one satellite at all times with all points on the celestial body ;
- said constellation comprising four common period elliptic-orbit satellites, said satellites having orbital parameters of period, inclination angle, eccentricity, right ascension of ascending nodes, arguments of parigee, and mean anomaly relationship, two of said satellites having periapses in one hemisphere of said celestial body and the other two of said satellites having periapses in the other hemisphere of said celestial body, said satellites continuously defining a tetrahedron which completely encloses said celestial body and whose planes do not intersect said celestial body'"'"'s surface so as to assure said continuous visibility.
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12. The method of providing a constellation of inclined elliptic artificial satellites for providing continuous global line-of-sight visibility to any point on the earth'"'"'s surface and within the maximum operating radius from the earth'"'"'s center of said satellites;
- said method comprising the step of orbiting four common-period elliptic-orbit satellites, said satellites having orbital parameters of period, inclination angle, eccentricity, right ascension of ascending nodes, arguments of perigee, and mean anomaly relationship, two of said satellites having perigees in one hemisphere and the other two of said satellites having perigees in the other hemisphere, said satellites continuously defining a tetrahedron which completely encloses the earth and whose planes do not intersect the earth'"'"'s surface so as to assure said continuous visibility.
- View Dependent Claims (13, 14)
Specification