GPS
I have one of the first really "dumb" GPS units that came out -- a Magellan Meridian XL -- and it still works fine as a backup to its descendants! Hell, even some of the old Loran-C units are still quite serviceable, but expect that to dwindle in coming years. Upshot; today's GPS units get fancier and more capable, but they still are charged with just one thing...telling you where you are. The number of sats a unit can "see" is based on what's flying overhead and to get a basic fix, all you need is two because the units triangulate regardless. How many they see is more of marketing hyperbole than functionality of purpose. The nice thing about the more they "see" the more consistent your readouts if one drops off for some reason. In flying, we talk about using "all the resources you have in the cockpit." Same goes for sailing.
