What is Global Positioning System

(GPS)

HOW IT FUNCTIONS…

• The Global Positioning System (GPS) is actually a worldwide radio-navigation system formed from a constellation of 27 satellites. 24 of which are currently in use, while the other 3 are present incase of an emergency, or any others break down

HOW IT WORKS…

• These satellites weigh between 3000 and 4000 pounds, and are solar powered. They glide through space at an altitude of approximately 11,000 nautical miles (above the Earth's surface), and circulates around the globe at about 12,000 miles. Which allows the satellites to make a complete orbit around the earth twice a day.

HOW IT WORKS…

• The orbit of each satellite, is arranged so the user has at least 4 satellites over-head, any where in the world, allowing the user to receive a relatively good signal. Five ground stations that make sure the satellites are working properly. GPS uses these satellites as reference points to calculate positions accurate to just a few meters. In fact, with advanced forms of GPS you can make measurements to better than a centimeter!

Here's how GPS works in five steps:

• The basis of GPS is "triangulation" from satellites.• To "triangulate," a GPS receiver measures distance using

the travel time of radio signals.• To measure travel time, GPS needs very accurate timing.• Along with distance, you need to know exactly where the

satellites are in space.• Finally you must correct for any delays the signal

experiences as it travels through the atmosphere. You must also correct for the clock differences between the GPS receiver and the satellites.

VEHICLE TRACKING WITH GPS

TRACKING USING GPS AND RFIDsource: IBO Past Papers