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A ground station, earth station, or earth terminal is a terrestrial radio station designed for extraplanetary telecommunication with spacecraft, or reception of radio waves from an astronomical radio source. Ground stations are located either on the surface of the Earth or in its atmosphere. Earth stations communicate with spacecraft by transmitting and receiving radio waves in the super high frequency or extremely high frequency bands (e.g., microwaves). When a ground station successfully transmits radio waves to a spacecraft (or vice versa), it establishes a telecommunications link. A principal telecommunications device of the ground station is the parabolic antenna. Ground stations may have either a fixed or itinerant position. Article 1 § III of the ITU Radio Regulations describes various types of stationary and mobile ground stations, and their interrelationships. Specialized ''satellite earth stations'' are used to telecommunicate with satellites—chiefly communications satellites. Other ground stations communicate with manned space stations or unmanned space probes. A ground station that primarily receives telemetry data, or that follows a satellite not in geostationary orbit, is called a ''tracking station''. When a satellite is within a ground station's line of sight, the station is said to have a ''view'' of the satellite. It is possible for a satellite to communicate with more than one ground station at a time. A pair of ground stations are said to have a satellite in ''mutual view'' when the stations share simultaneous, unobstructed, line-of-sight contact with the satellite. ==Telecommunications port== A ''telecommunications port''—or, more commonly, ''teleport''—is a satellite ground station that functions as a hub connecting a satellite or geocentric orbital network with a terrestrial telecommunications network, such as the Internet. Teleports may provide various broadcasting services among other telecommunications functions,〔http://www.shincorp.com/IR/SATTEL/annual_ssa/2003_content/glossary.pdf〕 such as uploading computer programs or issuing commands over an uplink to a satellite.〔http://www.bisenius.com/index.cfm?fuseaction=&id=62〕 In May 1984, the Dallas/Fort Worth Teleport became the first American teleport to commence operation. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ground station」の詳細全文を読む スポンサード リンク
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