Global Positioning System
GPS is a complex technology, but understanding it can be quite easy if you take it one step at a time. This tutorial is designed to give you a good basic understanding of the principles behind GPS without loading you down with too much technical detail. For those details see the reference links in our GPS Guide.
We recommend that you follow the tutorial in the order that it is presented, especially the "How GPS works" section. In that section the logic of the explanation develops one step at a time. Trying to figure out where you are and where you are going is probably one of man's oldest pastimes. Navigating and positioning are crucial to so many activities and yet the process has always been quite cumbersome. Over the years, all kinds of technologies have tried to simplify the task, but every one has had some disadvantage.
Finally, the U.S. Department of Defense decided that the military had to have an extremely precise form of worldwide positioning. And fortunately they had the kind of money ($12 billion!) it took to build something really good. The result is the Global Positioning System, a system that's changed navigation forever.