Global Positioning System, or GPS (noun, “GLOW-ball Poh-ZIH-shun-ing SIS-tem”)
This is a system that can track location by using satellites in space and receivers on Earth. GPS can also calculate where something is and how fast it’s moving. The system is run by the U.S. Air Force and uses a network of more than 30 satellites that orbit the planet. These satellites send out regular signals that can be detected on Earth. Any device with a GPS receiver — such as a smartphone — can receive these signals.
A GPS receiver measures how long it takes for signals from different satellites to hit it. It then calculates its position from that information. Once the GPS receiver knows its own position it can place that location on a map. Then, the map can use the location information to calculate how to get from that spot to wherever a person wants to go.
The system relies on stations on Earth to communicate with the satellites. These stations track each satellite’s location in space and the health of its batteries. They can also change a satellite’s position around the Earth.
Lots of things now have GPS receivers inside, including smartphones, cars and even dog collars. People put GPS receivers on anything they want to find if it gets lost, or to help them travel to a new place. But they won’t help you if you’re inside a building. GPS signals are very weak. They can be blocked by mountains or buildings.
In a sentence
Scientists use tags with GPS receivers on them to help track wild animals as they go about their lives.