Amateur Radio operators use a system called APRS to track their location. Some handheld and mobile radios come with APRS, or ham operators can use a computer or smartphone top update and share their location with other operators.
Essex APRS Map:
Here’s a real-time map of amateur radio activity in Essex now:
iPhone APRS Application
Don’t want to splash out on expensive APRS equipment? If you have a smartphone, you can use this to report your position to an APRS server. It’s very easy to set up, and quite impressive.
Want to see a good example of APRS in action? Check out the Truckcam.tv site to see live video feeds from some Essex Hams