How does GPS know your exact location on Earth?

GPS knows your exact location on Earth by using special signals from satellites up in space.

Imagine you're playing hide and seek in a big park with 20 friends. Each friend has a unique way of calling out, like one says “hello” every second, another says it every 1.5 seconds, and so on. When you hear the calls, you can figure out how far away each friend is by counting how many seconds pass between their calls.

GPS works kind of the same way. There are satellites in space sending signals down to Earth, like your friends calling out. Your phone or GPS device listens for these signals and uses them to calculate where it is.

Each satellite sends a signal that includes the exact time it was sent. Your GPS device compares this with the time it receives the signal. The difference in time tells how far away the satellite is, just like counting seconds between calls in hide and seek.

By using signals from at least four satellites, your GPS can find your exact location on Earth, like knowing exactly where you're hiding in that big park!