I think everyone has a vague idea of Sat Nav working by picking up signals from satellites "Out There" somewhere. However, I got asked the question, "Why does a Sat Nav need to see 4 satellites to get a fix?". So I desided to find out. The first surprise was just how many satellites are involved.
We are working with Navteq to report new or missing map data. so if anyone finds a road or point of interest that is different to what is on the map, they can now report this directly to Navteq at:- http://mapreporter.navteq.com/dur-web-external/
Tom-Tom, Garmin and Navigon amongst others all have ranges of products with Western Europe maps and we are frequently asked about a Western European version for ProNav, our navigation system designed for HGV's and all larger vehicles.