Satellite communications are used in television, telephone, fax, telegraph and data.
The application areas of satellite communications are expanding, in addition to finance, securities, post and telecommunications, meteorology, earthquakes and other sectors, tele-education, telemedicine, emergency disaster relief, emergency communications, emergency television broadcasting, sea, land and air navigation, Internet telephony connected to the Internet, television and so on will be widely used.
The development of new technologies in satellite communications is endless. For example, very small aperture antenna earth station (VSAT) system, low and medium orbit mobile satellite communication system and so on have received widespread attention and application. Satellite communication is also an important part of the future global information highway. It is characterized by its wide coverage and large communication capacity.
Expanded Information:
Development
From 1954 onwards, the United States has used the moon, passive balloon satellites, copper pin passive dipole belt as a relay station, the telephone, television transmission and other passive satellite communications tests, but proved to be no great practical value. Until 1957, the former Soviet Union launched the first artificial satellite, only to make satellite communications into the active satellite test stage.
December 1958, the United States with the Atlas rocket will be a 150-pound "Skor" low orbit satellite into an elliptical orbit (perigee 200km, apogee 1,700km), the star on the transmitter output power of 8W, the frequency of 150MHz. satellite using tape recordings, will be the A-station messages (telephone calls, telegrams) sent, delayed forwarding to station B.
October 1960, the U.S. Department of Defense and the "Messenger" satellite was launched to an altitude of 1,000km, inclination of 28.3 ° orbit, the use of 2GHz frequency, with the above similar low-orbit delayed communications test.
In June 1962, NASA used a Delta rocket to send the "Electrostar" satellite into an elliptical orbit of 1,060-4,500km; in December of the same year, the "Relay" satellite was launched into an elliptical orbit of 1,270-8,300km, and the "Relay" satellite was launched into an elliptical orbit of 1,270-8,300km. In December of the same year, the "relay" satellite was launched into an elliptical orbit of 1,270-8,500km, and many telephone, television and fax data transmission tests were carried out between the United States, Europe and South America.
Baidu Encyclopedia - Satellite Communications