Raise your hand if you don't rely on GPS. Any takers? No?
Now raise your hand if you understand what your GPS is doing when it concludes "You are HERE". I don't see many hands this time, either.
We have reached an interesting situation, where many (if not most) sailors entrust the safe navigation of their ship to a little black box whose operating principle is known only by a rare few.
You don't need to understand how GPS works in order to use it. Nevertheless, it is undeniably interesting—and a bit humbling—to delve into the inner workings of our favourite navigation tool.