How a GPS Receiver
Works (an alternate site to visit if you don't have the Shockwave
plug-in installed for your Web browser)
NOVA Online: the online companion Web site for Lost at Sea--The Search
for Longitude, a new NOVA program (which first aired 6 October
1998). You'll find lots of interesting navigation- and GPS-related
information and activities, including Play GPS: The New
Navigation (a very cool Shockwave game which helps you to
visualize how GPS determines your position on Earth).
Virtual
Earthquake (the process used to locate the epicenter of an earthquake
is similar to the way in which the global postioning system determines
your location)