23 November 2016

Satellite Communications

A satellite is characterized by:

  • Its position relative to earth
  • Rotation time around the earth
  • How it handles communications

There are 3 types of satellites:

  • Low earth orbit (LEO) satellites are placed 160 – 480 km above earth. Many satellites are required to form a complete network. Since it is near the earth surface, it can send/receive signals quickly. They form a ring pattern than follows the earth’s curvature. A satellite circles the earth every 90 minutes.
  • Medium earth orbit (MEO) satellites are placed 9,600 - 19,200 km above earth. There are 12 different orbit patterns. The number of satellite required is less than LEO. It is usually used by government agencies for weather forecasting and gathering intelligence information.
  • Geostationary earth orbit (GEO) satellites are 35,600 km above earth. Its rotation time is 24 hours. Signals take longer to travel and gives rise to distortion. It is used for various services, such as data, voice, location-base, emergency services.
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