Webopedia on Google+Webopedia on TwitterWebopedia on FacebookTech Bytes Blog
Main » TERM » G »

GPS - Global Positioning System

Short for Global Positioning System, a worldwide MEOsatellite navigational system formed by 24 satellites orbiting the earth and their corresponding receivers on the earth. The satellites orbit the earth at approximately 12,000 miles above the surface and make two complete orbits every 24 hours. The GPS satellites continuously transmit digital radio signals that contain data on the satellites location and the exact time to the earth-bound receivers. The satellites are equipped with atomic clocks that are precise to within a billionth of a second. Based on this information the receivers know how long it takes for the signal to reach the receiver on earth. As each signal travels at the speed of light, the longer it takes the receiver to get the signal, the farther away the satellite is. By knowing how far away a satellite is, the receiver knows that it is located somewhere on the surface of an imaginary sphere centered at the satellite. By using three satellites, GPS can calculate the longitude and latitude of the receiver based on where the three spheres intersect. By using four satellites, GPS can also determine altitude.

GPS was developed and is operated by the U.S. Department of Defense. It was originally called NAVSTAR (Navigation System with Timing and Ranging). Before its civilian applications, GPS was used to provide all-weather round-the-clock navigation capabilities for military ground, sea, and air forces.

GPS has applications beyond navigation and location determination. GPS can be used for cartography, forestry, mineral exploration, wildlife habitation management, monitoring the movement of people and things and bringing precise timing to the world.







TECH RESOURCES FROM OUR PARTNERS
DID YOU KNOW?
11 Tips to Boost Your Wi-Fi Signal

It's not just your lawnmower and household tools that your neighbor won't return. Our top picks include everything from updating device firmware... Read More »

Interesting Times: Transformation in the IT Channel

Business transformation will remain the buzzword of the moment as channel firms continue to assess the direction of their companies in the age of... Read More »

What is a Virtual Private network (VPN)?

Companies and organizations will use a VPN to communicate confidentially over a public network and to send voice, video or data. Read More »

QUICK REFERENCE
29 Free Android Apps for Cash-Strapped Students

From wacky alarm clocks to lecture hall tools and after class entertainment, these Android apps are a good fit for a student's life and budget. Read More »

Network Fundamentals Study Guide

A network is a group of two or more computer systems or devices, linked together to share resources, exchange files and electronic communications.... Read More »

Computer Architecture Study Guide

This Webopedia  study guide describes the different parts of a computer system and their relations. Read More »