How does GPS work, and why is it so accurate?

GPS stands for Global Positioning System, and it helps us find where we are on Earth using special satellites.

Imagine you have a big clock in your bedroom, and it’s also on the kitchen table and in the living room. If all those clocks tick perfectly together, you can figure out how far away each one is, just like how GPS works with satellites up in space.

There are about 30 satellites orbiting Earth, each carrying a very accurate clock. They send messages down to your phone or car, telling the exact time they sent it. Your device gets those messages and uses the time it took for them to arrive, like how long it takes for you to walk from one room to another, to figure out how far away each satellite is.

By using signals from at least four satellites, your phone can calculate exactly where you are on Earth, like knowing which corner of a big room you're in based on the clocks ticking around you.

The clocks on the satellites are super precise, they lose only one second every 100 years! That means your phone can tell your location almost perfectly, like knowing exactly where you are in a giant playground with just a few clues.