SATELLITE COMMUNICATION

Sir Arthur Charles Clarke, CBE, FRAS(16 December 1917 – 19 March 2008) was a British science fiction writer, science writer, inventor, undersea explorer, and television series host. Clarke contributed to the popularity of the idea that geostationary satellites would be ideal telecommunications relays. He first described this in a letter to the editor of Wireless World in February 1945 and elaborated on this concept in a paper titled Extra-Terrestrial Relays – Can Rocket Stations Give Worldwide Radio Coverage?, published in Wireless World in October 1945.The geostationary orbit is now sometimes known as the Clarke Orbit or the Clarke Belt in his honour.

TYPES OF SATELLITE ORBITS

Based on inclination

Equatorial Orbit(i=0°

)

Polar orbit(i=90

°)

Other orbits

(0°<i<90°)

Medium Earth Orbit (MEO).

Based on Altitude

SATELLITE LINK

•What are uplink and downlink?The communication going from a satellite to ground is called downlink, and when it is going from ground to a satellite it is called uplink. When an uplink is being received by the spacecraft at the same time a downlink is being received by Earth, the communication is called two-way. If there is only an uplink happening, this communication is called upload. If there is only a downlink happening, the communication is called one-way.

SATELLITE COMMUNICATIONS SERVICESONE WAY LINK TWO WAY LINK

MERITS AND DEMERITS

MERITS

1).MOBILE COMMUNICATION CAN BE EASILY ESTABLISHED.

2). IT OFFERS LARGE BANDWITH.

3).SATELLITE COMMUNICATION IS ECONOMICAL.

DEMERITS

1).EFFICIENCY IS REDUCED DUE TO TIME GAP BETWEEN TALKS.

2). REPAIR OF SATELLITE IS IMPOSSIBLE.

REVOLUTION OF SATELLITES

• 1957 • October 4 : - First

satellite Sputnik • Sputnik 02

• 1958• Project Score

• 1960• First successful passive

satellite: Echo 1

• 1975 - Aryabhata

• 2003 - INSAT-3A

• 2007 - INSAT-4B

• 2012 - Megha-Tropiques

Sputnik 1

Gsat-7

INSAT

USES OF SATELLITES

Satellites that orbit the Earth have a number of uses:

(a) studying crops(b) military uses(c) global positioning satellites (GPS)(d) observing and forecasting weather(e) space telescopes for astronomy(f) telecommunications (using geostationary satellites)

WEATHER SATELLITE

GPS operation

MOBILE SATELLITE COMMUNICATION NETWORK

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