This document discusses satellite communication and the different types of satellite orbits. It provides details on some of the key events and innovations in satellite technology. The three main types of orbits discussed are low Earth orbit (LEO), medium Earth orbit (MEO), and geostationary Earth orbit (GEO). LEO satellites orbit closer to Earth while GEO satellites orbit at an altitude that matches Earth's rotation so they remain stationary over one position. The document also summarizes how satellites are used to relay communications between two ground stations on Earth.

1. Satellite Communication
K.M.Prabusankarlal
Department of Electronics &
Communication
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2. Electronic Communication
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 Sending Receiving and Processing information
through electronic system

3. Electromagnetic Spectrum
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4. Communication System
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5. Modulation and Demodulation
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6. Olden days Systems
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7. The Radio Experiment
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 1897, Marconi sent the first ever wireless communication over open
sea. The experiment, witnessed a message transversed over the
Bristol Channel a distance of 6 kms. The message read "Are you
ready"

8. Transatlantic transmissions
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 12 December 1901, using a 152.4-metre (500 ft) kite-
supported antenna for reception, the message was received at
Signal Hill in St John's, Newfoundland (now part of Canada)
signals transmitted by the company's new high-power station
at Poldhu, Cornwall. The distance between the two points was
about 3,500 kilometres

9. Wave Propagation
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 Ground Wave
 Sky Wave
 Space Wave

10. Sky Wave Propagation
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 Radio waves radiated at a high angle and reflected
by these layers return to earth at a distance from the
transmitter.

11. How does a satellite orbit?
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12. Orbit Types
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 There are three major orbits: geosynchronous orbit
(GEO), middle earth orbit (MEO), and low earth orbit
(LEO). The majority of communications satelites in
use are GEOs.

13. Low Earth Orbit (LEO)
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 LEO satellites are much closer to the earth than
GEO satellites, ranging from 500 to 1,500 km above
the surface.
 LEO satellites don’t stay in fixed position relative to
the surface, and are only visible for 15 to 20 minutes
each pass.

14. Low Earth Orbit (LEO)
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15. Medium Earth Orbit (MEO)
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 A MEO satellite is in orbit somewhere between 8,000
km and 18,000 km above the earth’s surface.
 MEO satellites are similar to LEO satellites in
functionality.
 MEO satellites are visible for much longer periods of
time than LEO satellites, usually between 2 to 8
hours.
 MEO satellites have a larger coverage area than
LEO satellites.

16. Iridium of Motorola
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17. Iridium of Motorola
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18. Geostationary Earth Orbit (GEO)
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 These satellites are in orbit 35,863 km above the
earth’s surface along the equator.
 Objects in Geostationary orbit revolve around the
earth at the same speed as the earth rotates. This
means GEO satellites remain in the same position
relative to the surface of earth.
• A GEO satellite’s distance from earth gives it a large
coverage area, almost a fourth of the earth’s surface.

19. Geostationary Earth Orbit (GEO)
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20. Artificial Satellites
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 The Soviet Union launched Sputnik 1 on Oct. 4,
1957. The world’s first artificial satellite

21. Artificial Satellites
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Sputnik-2 equipped with a rudimentary life support system
to keep its passenger, a dog named Laika

22. India’s First Satellite
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Aryabhatta April 19, 1975 , Soviet Intercosmos rocket

23. How do Satellites Work
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 Two Stations on Earth want to communicate through
radio broadcast but are too far away to use
conventional means.
 The two stations can use a satellite as a relay station
for their communication
 One Earth Station sends a transmission to the
satellite. This is called a Uplink.
 The satellite Transponder converts the signal and
sends it down to the second earth station. This is
called a Downlink.

24. GEO Communication Satellites
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25. Sections of a Satellite
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26. Satellite Frequency bands
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27. Launching Vehicles
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PSLV GSLV

28. Satellite Debris
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