How does GPS know the exact location of your phone?

GPS knows where your phone is by using signals from satellites that are up high in space.

Imagine you have a friend who lives far away, but they can tell you exactly how far they are from you by sending you a message on your phone. GPS works kind of like that, but with many friends (the satellites) all around the sky.

How it finds your location

Satellites send out messages to your phone, telling it when the message was sent. Your phone gets these messages and figures out how long it took for each one to arrive. From that, it can tell how far away each satellite is.

By using signals from at least four satellites, your phone can figure out its exact spot on Earth, like solving a puzzle with clues from different directions!

Why it’s so accurate

Each satellite is moving very fast and has very good clocks inside them. These clocks help the phone calculate distances more precisely, just like knowing exactly when you start running helps you measure how far you go.

Your phone can even tell if you're walking or driving, because it knows where you were a little while ago!

Take the quiz →

Examples

  1. A GPS receiver on your phone receives signals from satellites in the sky.
  2. The time it takes for each signal to reach your phone helps calculate its distance from the satellite.
  3. By using signals from multiple satellites, your phone can find your exact location.

Ask a question

See also

Discussion

Recent activity