초록 ▼

A communication system and methods for sharing a common communication frequency, without interfering with a second communication system which has a plurality of satellites operating in geostationary orbits (GO) and ground stations (GS) which communicate with the satellites (GEO) on the common commun

A communication system and methods for sharing a common communication frequency, without interfering with a second communication system which has a plurality of satellites operating in geostationary orbits (GO) and ground stations (GS) which communicate with the satellites (GEO) on the common communication frequency, is disclosed. Conventional geostationary satellites broadcast in C and K.sub.u bands. Ground stations (GS) which receive these signals must have their antennas pointed toward the plane of the Equator (EQ). Satellites (10) which occupy inclined orbits (LO) and communicate with terrestrial terminals (12) propagate beams of energy that do not intersect the plane of the Earth's Equator. Terrestrial terminals (12) in the northern hemisphere communicate with a satellite (10) only when the sub-satellite point of the satellite (10) is at a latitude more northerly than the terrestrial terminal (12). Terrestrial terminals (12) in the southern hemisphere communicate with a satellite (10) only when the sub-satellite point of the satellite (10) is at a latitude more southerly than the terrestrial terminal (12). The spatial isolation of signals achieved by this novel pointing method insures that both the geostationary and inclined orbit satellite systems do not interfere with each other.

대표청구항 ▼

[ What is claimed is:] [15.] A method for sharing a common communication frequency by a communication system, without interference with a second communication system, said second communication system having a plurality of satellites (GEO) operating in Equatorial orbital planes (GO) and ground statio

[ What is claimed is:] [15.] A method for sharing a common communication frequency by a communication system, without interference with a second communication system, said second communication system having a plurality of satellites (GEO) operating in Equatorial orbital planes (GO) and ground stations (GS) which communicate with said plurality of satellites (GEO) in said Equatorial planes (GO) on said common communication frequency; said method comprising the steps of:operating a constellation of satellites (10) in a plurality of inclined orbits; each one of said satellites (10) having a sub-satellite point on Earth (E);locating a plurality of terrestrial terminals (12) at latitudes in Earth's northern and southern hemisphere substantially above and below the Equator; each one of said plurality of terrestrial terminals (12) having an antenna for communicating with at least one of said satellites (10); said communicating carried out on a frequency common with said second communication system;communicating with at least one of said satellites (10) from one of said plurality of terrestrial terminals (12) in said northern hemisphere only when said sub-satellite point of said satellite (10) is also in said northern hemisphere at a latitude more northerly than that of said terrestrial terminal (12); andcommunicating with one of said satellites (10) from one of said plurality of terrestrial terminals (12) in said southern hemisphere only when said sub-satellite point of said satellite (10) is also in said southern hemisphere at a latitude more southerly than that of said terrestrial terminal (12).