How does a GPS device pinpoint your exact location?

A GPS device uses signals from satellites to find your location like a detective using clues from different places.

Imagine you have a toy phone that can talk to toy astronauts floating high above in space. These astronauts send messages down to Earth, and your toy phone listens for them. Each message tells the phone how far away it is from each astronaut.

Now imagine you're playing hide-and-seek with three friends, one behind the couch, one by the door, and one near the window. If they all shout out how far away they are from you, you can figure out where you must be hiding!

GPS works like this: your phone gets messages from satellites that tell it how far away each satellite is. Since the satellites are in different places above Earth, your phone uses those distances to guess exactly where you are, just like figuring out where you're hiding by listening to all your friends.

The GPS phone also needs to know what time it is very accurately. This helps it calculate distance correctly because the messages take a tiny bit of time to travel from the satellite to your phone. If the time isn’t right, it might think you’re in the next room when you're actually in your bedroom!