How does GPS work?

One of my favorite podcasts, the Naked Scientists, from Cambridge University, posted an episode on 2 May (2010) about "GPS - Where in the World Are We?" There is lots of science news in the episode, but the part the Seniors Class will be interested in is "The Basics - GPS and Satellite Navigation":
"How does the GPS in your car actually work? And what does the future hold for GPS? Meera went to meet Dr Chaz Dixon and Colin Lee to find out more...

"Where in the world am I?  We're looking at the science of the Global Positioning System, or GPS, this week.  We find out how satellites can tell you your location, as well as communicate with the bossy little box that tells you which way to drive... In Kitchen Science, we get back to basics and locate ourselves using a map and compass!"

Click here to litsten to this portion of the broadcast.

You'll also need to listen to the following section, "The Cosmic Positioning System - GPS for Satellites" to find out how GPS satellites know where they are!

Click here to listen to this portion of the broadcast.

On the Kitchen Science portion of the podcast, you can learn how to find your position by triangulation, with a compass and a map. Click here to listen, and here to read instructions about how to be your own GPS (that's Global Positioning System).

If you're interested in science, subscribe to the podcast with this link, or through iTunes.  This is not particularly a show for children, but the some parts of each podcast episode are always easily understood - particularly the Kitchen Science section.

photo cc licensed flickr photo shared by mroach