What is GPS?
GPS is an acronym for Global Positioning System. It is a system developed from Global Navigation Satellite System(GNSS). GPS is operated by United States.
Similar to GPS, other systems are also developed by countries like China, India and Russia.
Using GPS it is possible to get the position of any location on earth surface by making use of GPS devices. These GPS receivers form a cone of visibility into the space. A minimum of 4 satellites normally have to be present in visibility cone of GPS device for identifying the position.
What are Various Components of GPS?
GPS mainly consists of 3 different components.
- Space Segment
- Control Segment
- User Segment
Space segment of GPS consists of 24 satellites, which are revolving in medium earth orbits (MEO). Medium earth orbits are present at an altitude of about 20,200 Kms above the earth surface.
There will be 6 such orbits in case GPS system. These orbits are positioned at an inclination of 30 degree with respect to each other.
All satellites arranged into 6 orbits with 4 satellites in each orbit. It takes approximately 12 hours for each satellite to complete revolution in the orbit.
These orbits and satellites are positioned in such a fashion, it is possible to have a minimum of 4 satellites always from any location on earth surface.
Also there exists a highly accurate atomic clock system, which is used for sending time related information in the form of signals to the ground stations or devices.