Global Positioning System (GPS) is a global satellite navigation system; based in space to provide critical information about location, weather etc. The GPS system is partly based on ground based Radio navigation system.
There are three distinct part of Global Positioning System:
First part of GPS has satellites that orbit 20000 kms above the earth in circular orbits of 12 hours. Each satellite takes 24 hours to complete a circle around Earth. The satellites are divided into six groups and each group has its own path to follow. These satellites capture the movements and send the radio signals with the information on Earth. The ground based system detects the radio signals and determine the receiver's position in terms of longitude, latitude and height.
The second part of GPS is the ground system that has an antenna and a receiver along with the communication tools for transmitting the information to the data center. The receiver much like car radio antenna detects the satellite signals and transmits them as electronic currents to the site receiver. The receiver then diverts the signals into various designated channels for a particular satellite and frequency at a particular timing.
Data center is the third part of GPS that monitors and controls the global GPS station and also retrieves and analyzes the data with the help of automated computer. The output can determine the location and distance between the satellite and the receiver. Global Positioning System is commonly used in vehicle tracking, interactive maps, Bus Route Announcement and various location based services.