Medium-earth-altitude satellite-based cellular telecommunications
First Claim
1. A method of controlling the communication of a plurality of telecommunication satellites in a cellular telephone communication system, comprising the steps of:
- determining a sequence of different focal directions for at least one antenna on each of said satellites over a predetermined orbital period, said focal direction being adjusted at a rate which is varied during said predetermined orbital period, the rate of focal direction adjustment for each of said satellites being related to others of said satellites during at least a portion of said orbital period; and
periodically transmitting command signals to each of said satellites from at least one planetary-based control station which provides the information needed by said satellites to implement said sequence of focal directions.
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Accused Products
Abstract
A satellite-based cellular telecommunications system employing a constellation of telecommunications satellites in medium earth orbit to provide multibeam radio frequency (rf) communications links for worldwide cellular telephone service with a minimum number of satellites. The telecommunications satellites are placed in a plurality of inclined orbits about the earth at an altitude of between approximately 5600 and 10,000 nautical miles. The characteristics of the orbits, such as the number of orbits, the inclination of each orbit, the number of satellites in each orbit and the altitude of the satellites, are tailored to maximize the coverage area of the satellites and their related line-of-sight elevation angles, while minimizing propagation time delays, the number of beam-to-beam and satellite-to-satellites handovers, and the total number of satellites. The present invention also includes several additional features which essentially eliminate beam-to-beam and satellite-to-satellite handovers, thus dramatically reducing the likelihood of dropouts.
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Citations
7 Claims
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1. A method of controlling the communication of a plurality of telecommunication satellites in a cellular telephone communication system, comprising the steps of:
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determining a sequence of different focal directions for at least one antenna on each of said satellites over a predetermined orbital period, said focal direction being adjusted at a rate which is varied during said predetermined orbital period, the rate of focal direction adjustment for each of said satellites being related to others of said satellites during at least a portion of said orbital period; and periodically transmitting command signals to each of said satellites from at least one planetary-based control station which provides the information needed by said satellites to implement said sequence of focal directions. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification