How does GPS know where you are?
The Dot That Knows
How does GPS know where you are?
You're walking through a city you've never been to before. You pull out your phone, open the map, and — boom — a little blue dot shows exactly where you are. No wires. No cameras watching from above. Just... satellites in space, quietly doing math. How does that work?
GPS needs at least four satellites to find you. Right now, there are about thirty of them circling Earth, each one taking twelve hours to loop around the planet. They're arranged so that no matter where you stand — desert, ocean, mountaintop — at least four can "see" you at once.
