Trw Limited

Peter H Cress

Michael Horstein

Roger J Rusch

Brian R Williams

A multiple altitude satellite relay system is disclosed in which Medium Earth Orbit satellites are continuously linked with at least one geosynchronous satellite to provide uninterrupted relaying of messages and data. The Medium Earth Orbit satellites are synchronized with the geosynchronous satellites to produce continuous links. A parameter to achieve the synchronization involves the positions of the Medium Earth Orbit satellite relays relative to the positions of the geosynchronous satellite relays. Another parameter to achieve synchronization involves the ratio between the orbital periods of the geosynchronous satellite relays relative to the orbital periods of the Medium Earth Orbit satellite relays. These parameters may be further adjusted to provide continuous links above the horizon of the earth. An additional satellite relay system is disclosed in which the high-orbit satellite need not be in geosynchronous orbit and in which a high-orbit satellite communicates over a continuous unbroken link with a low-orbit satellite. A further satellite relay system is disclosed in which more than two satellites are arranged at discrete orbit altitudes, again providing a continuous, unbroken daisy-chain link between satellites.

Multiple altitude satellite relay system and method

A multiple altitude satellite relay system is disclosed in which Medium Earth Orbit satellites are continuously linked with at least one Geosynchronous satellite to provide uninterrupted relaying of messages and data. The Medium Earth Orbit satellites are synchronized with the Geosynchronous satellites to produce continuous links. A parameter to achieve the synchronization involves the positions of the Medium Earth Orbit satellite relays relative to the positions of the Geosynchronous satellite relays. Another parameter to achieve synchronization involves the ratio between the orbital periods of the Geosynchronous satellite relays relative to the orbital periods of the Medium Earth Orbit satellite relays. These parameters may be further adjusted to provide continuous links above the horizon of the earth.

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.

Medium-earth-altitute satellite-based cellular telecommunications

Medium-earth-altitude satellite-based cellular telecommunications

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-satellite 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. between the plug and the anchor to prevent the plug from entering the opening in the vessel.

Growing community of inventors

Manhattan Beach, CA, United States of America

Peter H Cress