Just a word about Vasi's and Papi's, as I do maintenance on these devices.  Usually you just have a white light bulb, with a red lense about two inches blocking the lower half of the light, so when you are viewing the light from a low enough angle, all you see is the light through the red lense. 

And as for LORAN, it was basically the pre satellite version of GPS. Instead of using satellites for informations, it uses signals from ground transmitters to figure out its location.