US3836969A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Geo-synchronous satellites in quasi-equatorial orbits
Assignee: RCA Corp
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Filing: 1971-10-26
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Granted: 1974-09-17
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Expires: 1991-10-26
Abstract
Abstract The method of the selection of launch conditions for a satellite at substantially synchronous altitude above the earth in a slightly inclined orbit relative to the equatorial plane of the earth to limit the inclination that may be induced by perturbations for significantly long periods of time without the need of orbit adjusting means (north-south station keeping means) aboard the satellite. One or more such satellites are arranged in a communication system in cooperation with at least one ground station. In a two-satellite system a communication channel is continuously operated between at least one satellite and the ground station notwithstanding solar outages. D R A W I N G
Inventors
- 👤 D Bond
- 👤 J Holman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:50
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/14; H04B7/15; H04B7/185; H04B7/19; B; B64; B64G; B64G1/00; B64G1/10; B64G1/1007; B64G1/1085; B64G1/22; B64G1/24; B64G1/242; B64G1/2425; B64G1/2429
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
213 words
A satellite communication system comprising: at least two satellites at substantially synchronous altitude above the earth and in progressively inclined orbits relative to the equatorial plane of the earth, each of said satellites having relay means, including an antenna, adapted for receiving signals from one earth station and retransmitting said signals to another earth station, each of said satellites having an orbit with a solar outage period that does not overlap the solar outage period of the other of said two satellites, the spacing between said two satellites being such that each satellite is respectively adapted to receive signals from and retransmit signals to any of said earth stations, each of said orbits being selected such that the inclination of each orbit is initially adjusted to a selected maximum inclination, whereby said orbit thereafter decreases towards zero inclination, and subsequently increases at least to said selected maximum inclination during a predetermined time period, said inclination of each satellite being initially 7*20'' or less and being selected in accordance with said predetermined time period, and the right ascension of the ascending node ( Omega ) being between 180* and 360* whereby, during said predetermined time period, the orbit inclination remains bounded for each of said satellites without the need of north-south station keeping means.
Claim 2
Dependent Claim
213 words
A satellite communication system comprising: at least two satellites at substantially synchronous altitude above the earth and in progressively inclined orbits relative to the equatorial plane of the earth, each of said satellites having relay means, including an antenna, adapted for receiving signals from one earth station and retransmitting said signals to another earth station, each of said satellites having an orbit with a solar outage period that does not overlap the solar outage period of the other of said two satellites, the spacing between said two satellites being such that each satellite is respectively adapted to receive signals from and retransmit signals to any of said earth stations, each of said orbits being selected such that the inclination of each orbit is initially adjusted to a selected maximum inclination, whereby said orbit thereafter decreases towards zero inclination, and subsequently increases at least to said selected maximum inclination during a predetermined time period, said inclination of each satellite being initially 7*20'' or less and being selected in accordance with said predetermined time period, and the right ascension of the ascending node ( Omega ) being between 180* and 360* whereby, during said predetermined time period, the orbit inclination remains bounded for each of said satellites without the need of north-south station keeping means.
Claim 3
Dependent Claim
22 words
A system according to claim 1 including an earth station having a directive antenna for tracking at least one of said satellites.
Claim 4
Dependent Claim
21 words
A system according to claim 2 wherein the directive antenna is programmed to track said satellite according to a predetermined schedule.
Claim 5
Dependent Claim
27 words
A system according to claim 2 wherein said directed antenna is controlled by means in said ground station responsive to a signal received from said one satellite.
Claim 6
Dependent Claim
47 words
A system according to claim 3 wherein said schedule is programmed to direct the antenna to oscillate daily in sequentially decreasing and increasing amplitudes to track the progressively inclined orbit of said one satellite, said program being arranged to provide such oscillations for at least several years.
Claim 7
Dependent Claim
14 words
A system according to claim 5 whErein: said program is effected by mechanical means.
Claim 8
Dependent Claim
14 words
A system according to claim 5 wherein: said program is effected by electronic means.
Claim 9
Dependent Claim
79 words
A system according to claim 1 including: a ground station having a fixed fan-beam antenna directed to the approximate orbit location of each of said satellites, said antenna being arranged to have a beam pattern which is relatively broad along the major axis of motion of the satellite and relatively narrow in the direction at right angles to said major axis whereby the beam pattern corresponds to the boundaries of the secular changes in the orbit of said satellite.
Claim 10
Dependent Claim
67 words
A system according to claim 1 including two earth stations, one of said stations serving as a signal transmission station, and the other of said stations serving as a receiving station of signals relayed from said satellites, means at said receiving station for selectively receiving signals from one of said satellites, and switching means for transferring the selection means to the other satellite to avoid solar outages.
Claim 11
Dependent Claim
154 words
A satellite communication system comprising: at least one satellite at substantially synchronous altitude above the earth, each satellite in a progressively inclined orbit relative to the equatorial plane of the earth, an earth station having means for exchanging communication signals with said satellite, a steerable antenna at said earth station, and means for steering said antenna to track said satellite, said orbit being selected such that the inclination of the orbit is initially adjusted to a selected maximum inclination, whereby said orbit thereafter decreases towards zero inclination, and subsequently increases at least to said selected maximum inclination during a predetermined time period, said inclination being initially 7*20'' or less and being selected in accordance with said predetermined time period, and the right ascension of the ascending node ( Omega ) being between 180* and 360* whereby, during said predetermined time period, the orbit inclination remains bounded without the need of north-south station keeping means.
Claim 12
Dependent Claim
154 words
A satellite communication system comprising: at least one satellite at substantially synchronous altitude above the earth, each satellite in a progressively inclined orbit relative to the equatorial plane of the earth, an earth station having means for exchanging communication signals with said satellite, a steerable antenna at said earth station, and means for steering said antenna to track said satellite, said orbit being selected such that the inclination of the orbit is initially adjusted to a selected maximum inclination, whereby said orbit thereafter decreases towards zero inclination, and subsequently increases at least to said selected maximum inclination during a predetermined time period, said inclination being initially 7*20'' or less and being selected in accordance with said predetermined time period, and the right ascension of the ascending node ( Omega ) being between 180* and 360* whereby, during said predetermined time period, the orbit inclination remains bounded without the need of north-south station keeping means.
Claim 13
Dependent Claim
17 words
A system according to claim 10 wherein said antenna is steered by means responsive to a clock.
Claim 14
Dependent Claim
19 words
A system according to claim 10 wherein said antenna is steered by means responsive to an electronically controlled program.
Claim 15
Dependent Claim
21 words
A system according to claim 10 wherein said antenna is steered by means responsive to tracking signals received from said satellite.
Claim 16
Independent Claim
164 words
A method of operating a communication satellite system comprising the steps of launching a satellite into an inclined progressively changing orbit such that Omega is selected to minimize the maximum inclination of the orbit throughout a predetermined time period defining the life of the satellite, wherein Omega is the right ascension of the ascending node, the value of Omega being such that the inclination of the orbit initially increases to a selected maximum inclination, thereafter decreases towards zero inclination, and subsequently increases to said selected maximum inclination, selecting the inclination of said satellite to be initially 7*20'' or less in accordance with said predetermined time period, selecting the right ascension of the ascending node ( Omega ) to be between 180* and 360* whereby, during said predetermined time period, the orbit inclination remains bounded without the need of north-south station keeping means, transmitting signals from a first earth station to said satellite, and relaying said signals from said satellite to a second earth station.
Claim 17
Independent Claim
164 words
A method of operating a communication satellite system comprising the steps of launching a satellite into an inclined progressively changing orbit such that Omega is selected to minimize the maximum inclination of the orbit throughout a predetermined time period defining the life of the satellite, wherein Omega is the right ascension of the ascending node, the value of Omega being such that the inclination of the orbit initially increases to a selected maximum inclination, thereafter decreases towards zero inclination, and subsequently increases to said selected maximum inclination, selecting the inclination of said satellite to be initially 7*20'' or less in accordance with said predetermined time period, selecting the right ascension of the ascending node ( Omega ) to be between 180* and 360* whereby, during said predetermined time period, the orbit inclination remains bounded without the need of north-south station keeping means, transmitting signals from a first earth station to said satellite, and relaying said signals from said satellite to a second earth station.
Claim 18
Dependent Claim
132 words
A method of operating a communication satellite system according to claim 14 comprising the steps of launching a second satellite into an inclined progressively changing orbit having its Omega substantially equal to the Omega of the first mentioned satellite, the orbit of said second satellite being selected so that the solar outaGe period of each of the first and second satellites do not overlap, and the spacing between said first and second satellites being such that each satellite is respectively adapted to receive and transmit signals with any of said two earth stations, transmitting said signals to said first mentioned and second satellites, inhibiting the reception of said signals from said first mentioned satellite to said second earth station and relaying said signals from said second satellite to said second earth station.
Claim 19
Dependent Claim
52 words
A method according to claim 14 wherein the life of said satellite is at least several years, including the steps of oscillating an antenna at each of said earth stations in sequentially decreasing and increasing amplitudes, and programming said oscillations for at least several years corresponding to the life of the satellite.
Claim 20
Dependent Claim
201 words
A satellite communication system comprising: at least two satellites at substantially synchronous altitude above the earth and in progressively inclined orbits relative to the equatorial plane of the earth, each of said satellites having transmitting means, including an antenna, adapted for transmitting signals to at least two earth stations, each of said satellites having an orbit with a solar outage period that does not overlap the solar outage period of the other of said two satellites, the spacing between said two satellites being such that each satellite is respectively adapted to transmit signals to both of said earth stations, each of said orbits being selected such that the inclination of each orbit is initially adjusted to a selected maximum inclination whereby said orbit thereafter decreases towards zero inclination, and subsequently increases to said selected maximum inclination during a predetermined time period, said inclination of each satellite being initially 7*20'' or less and being selected in accordance with said predetermined time period, and the right ascension of the ascending node ( Omega ) being between 180* and 360* whereby, during said predetermined time period, the orbit inclination remains bounded for each of said satellites without the need of north-south station keeping means.
Claim 21
Dependent Claim
201 words
A satellite communication system comprising: at least two satellites at substantially synchronous altitude above the earth and in progressively inclined orbits relative to the equatorial plane of the earth, each of said satellites having transmitting means, including an antenna, adapted for transmitting signals to at least two earth stations, each of said satellites having an orbit with a solar outage period that does not overlap the solar outage period of the other of said two satellites, the spacing between said two satellites being such that each satellite is respectively adapted to transmit signals to both of said earth stations, each of said orbits being selected such that the inclination of each orbit is initially adjusted to a selected maximum inclination whereby said orbit thereafter decreases towards zero inclination, and subsequently increases to said selected maximum inclination during a predetermined time period, said inclination of each satellite being initially 7*20'' or less and being selected in accordance with said predetermined time period, and the right ascension of the ascending node ( Omega ) being between 180* and 360* whereby, during said predetermined time period, the orbit inclination remains bounded for each of said satellites without the need of north-south station keeping means.
Claim 22
Dependent Claim
43 words
A system according to claim 17 including two earth stations, each of said stations serving as a signal receiving station of signals transmitted from said satellites, and means at each of said receiving stations for selectively receiving signals from one of said satellites.
References Cited (Backward Citations)
US3706037A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-16 | 1978-03-18 | 1978-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-16 | 1982-03-18 | 1982-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-16 | 1986-03-18 | 1986-09-17 | $7700.00 | Window Closed / Lapsed |