Satellite Communication

A heavy object which goes around in space due to the effect of gravitational force, used for broadband communication. In telecommunications, the use of artificial satellites to provide communication links between various points on Earth. Satellite communications play a vital role in the global telecommunications system.

Satellite communication has two main components:Ground segment: Ground segment, which consistsof fixed or mobile transmission, reception, and

, and ancillary equipment. Space segment: Space segment which primarily is the satellite itself.

A typical satellite link involves the transmission or up linking of a signal from an Earth station to a satellite. The satellite then receives and amplifies the signal and retransmits it back to Earth, where it is received and re-amplified by Earth stations and terminals

Satellite receivers on the ground include direct-to-home (DTH) satellite equipment, mobile reception equipment in aircraft, satellite telephones, and hand held devices.

1) Orbit:The path a Satellite follows around a planet is defined as an orbit.

Types of Satellite Orbits are:• Lower Earth orbit (LEO)• Middle Earth Orbit (MEO)• Geo Stationary Orbit (GEO) Types of Satellites:

• Passive satellite• Active satellite

Types of Satellites:

A) Passive Satellite: These only reflect signals from one Earth station to another, or from several Earth stations to several others. It reflect the incident EM radiation without any modification or amplification. It can't generate power.

B) Active Satellites: Satellites which can transmit power are called active satellite. These amplify or modify and retransmit the signal from the earth. Requires low power earth station and is less costly.

2) Antenna:

Antenna (or aerial) is a transducer that transmits or receives electromagnetic waves. In other words, antennas convert electromagnetic radiation into electrical current, or vice versa. Antennas generally deal in the transmission and reception of radio waves.