What was the first radio navigation system capable of triangulating your position, and when was it built? How accurate was it and what was its range?
This does not have to be GPS or a satellite system. A series of 3 or more radio towers, broadcasting beacon signals, can be anywhere on Earth. A receiver in theory can calculate its position if it knows the distance to each one.
This would require two things: (1) Accurate chronometers so that the receiver and beacons have their time in sync. (2) Precise chronometers capable of resolving time down to the millisecond or finer. These two things are needed because the speed of light is so fast, a difference of 1 millisecond evaluates to an error of 30 km (19 mi). OTOH, 1 microsecond would be 30 meters, which is good enough accuracy for the old days.
Can those things even be done with old analogue tech from the WW2 era or even earlier? I'm hoping to find a system capable of resolving your position down to 1 km or so, which should be good enough for naval purposes in the old days.
I did look into this around the WW2 era. I found The Battle of the Beams, which seems to revolve around a directional beam sent out towards London, and probably based on distance but only by measuring strength/weakness of the signal. I found The Sonne System and its predecessor, the Elektra, but again, those seemed to be based on finding your direction to an anchor beacon, not distance.
I couldn't find any that measure time delay from 3 or more anchor beacons. The system doesn't actually have to calculate distance and then position. That might be asking too much from the 1940's. Instead, it just needs to measure time delay and display it on a screen. The crew of a ship or airplane could then do the calculations.
(P.S., I couldn't find any better tags. I saw "radiation" but not "radio." Can't think of what else would be a good tag except electricity and computers.)
