Why use satellite?
Satellite communication is just one example of wireless communication systems. Familiar examples of wireless systems are all around us, such as radio and television broadcasting and mobile and cordless telephones. These systems rely on a network of ground-based transmitters and receivers and for this reason they are often referred to as "terrestrial" systems.
Satellite communication systems differ from terrestrial systems in one obvious but important way - the transmitter is moved from the ground to the sky. Because a satellite can "see" about one-third of the earth's surface from its position in space, it is able to serve a very large geographical area, thus offering a number of advantages:
- as little as three satellites can cover almost the whole of the earth's surface, with the exclusion of the sparsely populated polar regions. To achieve the same coverage by terrestrial means would require a very large and expensive network of ground-based transmitters.
- services can be quickly introduced, since coverage is available for everyone from day one. There is no need for a phased introduction of ground-based transmissions with a simple antenna, those located even in the most remote locations can still enjoy the same level of service as someone living in the centre of a major city.
- satellites naturally span national boundaries, providing numerous possibilities for truly international services.
One major use of satellites familiar to everyone is satellite television broadcasting. The Eutelsat satellites deliver hundreds of television channels every day throughout a very large coverage area spanning Europe, the Middle East, Africa and Central Asia. The satellites are also used to supply television signals to terrestrial transmitters and to exchange signals between television studios.
Other applications of satellite communications include high speed internet, telephony and corporate networks for multinational businesses.
|
