Technology
How does GPS work?
GPS works by using a network of satellites that constantly broadcast their position and the time. Your device receives signals from several satellites and calculates its exact location from how long each signal took to arrive.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how GPS works.
Step by step
- 1Around 30 satellites orbit Earth, each broadcasting its position and a precise time.
- 2Your receiver measures the tiny delay of signals from at least four satellites.
- 3From those delays it triangulates latitude, longitude, and altitude.
- 4Atomic clocks on the satellites make the timing precise.
Frequently asked questions
- How many satellites does GPS need?
- At least four to pin down your 3D position (latitude, longitude, and altitude).
- Does GPS need the internet?
- No — GPS itself works from satellite signals; the internet only helps load maps and speed up the first fix.
- Why is GPS sometimes inaccurate?
- Tall buildings, tree cover, and atmospheric effects can delay or block satellite signals.