Geostationary Orbit (GEO)

As all the points on circular orbit are at equal distance from earth's surface, a satellite remains at a particular distance from earth at all the time in circular orbits.
The circular equatorial orbit is exactly in the plane of the equator on the earth.
If the satellite is moving in the circular-equatorial orbit and its angular velocity is equal to earth's angular velocity, the satellite is said to be moving along with the earth.
As the satellite appears stationary from the earth it is called Geostationary Orbit.

Features of Geostationary Orbit (GEO) :

It is a Circular orbit.
The angular velocity of the satellite is equal to the angular velocity of the earth.
Period of revolution is equal to the period of rotation of the earth.
Geostationary Orbit (GEO) is in equatorial plane i.e. zero inclination with the equator.

A communication satellite in GEO orbit can cover almost 1/3 of Earth's surface, providing a more extensive reach than what any terrestrial network can achieve.
As the geosynchronous satellites remain stationary, users can fix their satellite dishes in the right direction obtaining reliable and secure communications.
Geostationary Orbit (GEO) satellites are proven, reliable and secure - with a lifespan of 10-15 years.
Compared to the Low Earth Orbit -LEO and Medium Earth Orbit - MEO systems, GEO systems have greater bandwidth due to which latter provide two-way data, voice and broadband services that may be impractical for other types of systems.

They require line-of-sight communication paths between terrestrial antennae and the satellites.
This is problematic, especially for mobile applications and in urban areas where tall buildings and other structures may block line-of-sight communication for hand-held mobile terminals.
Also, there are transmission delays associated with GEO systems, particularly for high-speed data.