EP0213355A1
Expired / Lapsed
EP
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Tetrahedral multi-satellite continuous-coverage constellation
Assignee: Individual
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Filing: 1986-07-17
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Granted: —
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Expires: 2006-07-17
Abstract
Abstract An improved, optimized, four-satellite tetrahedral constellation (S₁ to S₄) 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 visibility 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 aplicable to any celestial body wherein two satellites have two periapses in one hemisphere and the other two satellites have periapses in the other hemisphere.
Inventors
- 👤 John E. Draim
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 09:21
CPC Classifications
B; B64; B64G; B64G1/00; B64G1/10; B64G1/1085; B64G1/1007; B64G1/22; B64G1/24; B64G1/242; H; H04; H04B; H04B7/00; H04B7/14; H04B7/15; H04B7/185; H04B7/195
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
92 words
A constellation of inclined elliptic satellites for providing continous 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 constellation comprising four common-period elliptic-orbit satellites (S₁ to S₄), two of said satellites having perigees on one hemisphere and the other two of said satellites having perigees in the other hemisphere, said satellites continuously defining a tetrahedron (A,B,C,D) which completely encloses the earth and whose planes do not intersect the earth's surface so as to assure said continuous visibility.
Claim 2
Dependent Claim
92 words
A constellation of inclined elliptic satellites for providing continous 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 constellation comprising four common-period elliptic-orbit satellites (S₁ to S₄), two of said satellites having perigees on one hemisphere and the other two of said satellites having perigees in the other hemisphere, said satellites continuously defining a tetrahedron (A,B,C,D) which completely encloses the earth and whose planes do not intersect the earth's surface so as to assure said continuous visibility.
Claim 3
Dependent Claim
23 words
The constellation of satellites of Claim 1 wherein said one hemisphere is the Northern Hemisphere and said other hemisphere is the Southern Hemisphere.
Claim 4
Dependent Claim
22 words
The satellite constellation of Claim 1 wherein the minimum constellation or satellite period is substantially 27 hours, with no maximum period limitation.
Claim 5
Dependent Claim
54 words
The satellite constellation of Claims 1, 2 or 3 wherein at least one of said orbital parameters is fixed so as to favor coverage of selected geographical regions while maintaining said continuous global line-of-site visibility, said orbital parameters being inclination angle, eccentricity, right ascensions of ascending nodes, arguments of perigee, and mean anomaly relationship.
Claim 6
Dependent Claim
29 words
The satellite constellation of Claim 1 wherein the axis of symmetry of said satellite constellation is selected so as to provide a predetermined orientation with respect to the earth.
Claim 7
Dependent Claim
99 words
A constellation of satellites for providing continuous line-of-sight visibility to any point on the surface of a celestial body and within the maximum operating radius from the body's center of said satellites; said constellation comprising four common period elliptic-orbit satellites, 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.
Claim 8
Dependent Claim
99 words
A constellation of satellites for providing continuous line-of-sight visibility to any point on the surface of a celestial body and within the maximum operating radius from the body's center of said satellites; said constellation comprising four common period elliptic-orbit satellites, 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.
Claim 9
Dependent Claim
45 words
A constellation of four satellites as in Claims 1, 2 or 3 wherein predetermined constellation periods may be selected in order to achieve a predetermined desired look angle from earth-bound or space-bound points, to values exceeding a predetermined positive visibility angle criteria greater than zero.
Claim 10
Dependent Claim
80 words
A constellation of four satellites as in Claims 1, 2 or 3, wherein any or all of the orbital parameters of inclination angle, eccentricity, right ascensions of ascending nodes, arguments of perigee and mean anomaly relationships are adjusted with predetermined excursions off the optimum for evel global coverage, so as to preferentially favor one hemisphere over the other as to minimum visibility or look angles, while always maintaining for both hemispheres complete and continuous coverage or visibility in both hemispheres.
Claim 11
Dependent Claim
91 words
A constellation of four satellites as in Claims 1, 2 or 3, wherein the constellation or satellite periods are selectively less than the 27-hour value required for complete global coverage, or wherein the various orbital parameters are adjusted with predetermined excursions off the optimum for the purpose of obtaining selective coverage distributions of critical areas, with the resulting satellite coverage gaps located geographically in selected nonimportant areas so that said gaps will cause an absence of or a minimization of adverse effect on the performance of the system using the array.
Claim 12
Dependent Claim
27 words
A constellation as in Claims 1, 2 or 3 further comprising at least one additional continuous coverage constellation overlaying said first recited constellation with any selected orientation.
Claim 13
Dependent Claim
37 words
A constellation as in Claims 1, 2 or 3 further comprising additional satellites with the same of similar orbital parameters overlaying said first recited constellation with any selected orientation so as to provide n-tuple redundant continuous coverage.
References Cited (Backward Citations)
DE1224159B
Cited
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