Satellite communication


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Satellite communication

  1. 1. • Introduction. • History. • How does a satellite work? • Types of satellite. • Application of Satellite communication. • Satellite Orbit. • Types of Satellite Orbit. • Summary.
  2. 2. • The use of satellite in communication systems has become very common now-a-days. • A communication satellite is a station in space that is used for telecommunication, radio and television signals. • The construction and launch cost of a satellite are extremely high.
  3. 3. • 4th October 1957 first Satellite SPUTNIK(Russia). • 1958 first active communication satellite TELSTAR-1. • 1963 first geostationary satellite SYNCOM 2(NASA). • 1965 first commercial geostationary satellite “Early Bird” 240 duplex telephone channels or 1 TV channel. • 19th April 1975 India’s first satellite launched by Aryabhatta.
  4. 4. 1. An Earth Station sends message in GHz range. (Uplink) 2. Satellite Receive and retransmit signals back. (Downlink) 3. Other Earth Stations receive message in useful strength area. 4. Main Earth Station is in Delhi, Kolkata, Chennai, Mumbai and Shilong
  5. 5. • Satellite are divided in four major categories as follow: •Communication Satellite. •Weather satellite. •Remote-sensing satellite. •Scientific satellite.
  6. 6. • Geostationary satellites when used for the communication application are called communication satellite. • They are used in such a application are TV transmission, military application, commercial application etc…. • International Telecommunication satellite. “INTELSAT” is often used in satellite communication. • More than 140 nation are interconnected via INTELSAT system to use for computer data, TV signals etc……
  7. 7. • These satellite are used for weather prediction, for taking the photographs of clouds. • TIROS-1 was the first weather satellite. Other weather satellites are Nimbus and Meteosat. • India’s “INTELSAT” satellite is being used for three application i.e. communication. • TV transmission and meteorology or weather prediction. Thus it is a multipurpose satellite.
  8. 8. • This types of satellite can be used to find out the condition of crops, forests or minerals underground, condition of soil etc… • Indian satellite IRS is a remote sensing satellite. • Form the information obtained from the remote sensing satellite detailed maps can be prepared.
  9. 9. • These satellites are relatively simpler and of short life span. • They are used to carry out various scientific studies. India’s “Aryabhatta” was a scientific satellite.
  10. 10. • In space, satellites move in certain specific paths. These paths are called as orbits. • The selection of a particular orbit depends on the following factor: •Transmission path loss. •Earth coverage area. •Delay time. •Time period for which the satellite should be visible.
  11. 11. • Low Earth Orbit (LEO) satellites. • Medium Earth Orbit (MEO) satellites. • Geosynchronous Earth Orbit (GEO) satellites.
  12. 12. • LEO is the short form of low earth orbit satellites. • They revolve around the earth in the orbits which are 500 to2000km above the earth. • The time taken for one revolution around the earth is about to one and half hours.
  13. 13. • The medium earth orbit satellites (MEO) are at much lower altitudes as compared to GEO satellite. • Typically the MEO satellites operate in the range of 5000km to 15000km above the earth. • The time taken for one revolution around the earth is about to 6hours.
  14. 14. • The satellites orbiting in the geostationary orbit are called geostationary satellites. • These satellites are at about 36000km above the earth’s surface. • The time taken for one revolution around the earth is about one day i.e. 24hours.
  15. 15. • The communication of video signals(TV), audio signals (telephones, satellite phones) and computer data (internet). • To gain meteorological or weather information. • To monitor the status of earth’s resources such as land, forests and oceans. • To spot our mineral resources, polluted areas, sources of pollution crops, lakes and rivers etc…….
  16. 16. • Introduction. • 4th October 1957 first Satellite launched. • 19th April 1975 India’s first satellite launched by Aryabhatta. • Three types of orbits • LEO -- one and half an hrs to complete one revolution. • MEO -- 6hrs to complete one revolution. • GEO -- 24hrs to complete one revolution.