Assisted GPS: How your phone knows where it is

Assisted GPS is used by millions of smartphone users every day to get driving directions, find places, and find themselves. As it turns out, the good old GPS satellite system, by itself, works very slowly and often not at all when you're indoors or walking beneath tall buildings. That's why the GPS software in your phone relies heavily on cellular and Wi-Fi networks to help it figure out where it is.

But ask a hundred people what those networks actually do to help the GPS system, and you might get a hundred different answers. We hope that this handy infographic will help clear up the mystery.