> I can imagine something like GPS was envisioned well before the first satellites were even launched into orbit. I don’t know about that. Maybe it was. What I

> I can imagine something like GPS was envisioned well before the first satellites were even launched into orbit. I don’t know about that. Maybe it was. What I do know is that we have documented speculation about satelite based navigation the days right after the launch of Sputnik. American scientist figured out the orbit of Sputnik independently from the Russians by measuring the dopler shift of the radio transmission with their radios. Then knowing where their radio is located they used an iterative optimisation process to identify the orbital parameters of the satelite. Immediately there they were talking about how if the orbit of the satelite were known they could use the same process backwards to fix their location. That was 21 years before the launch of the first GPS satelite. Now, that is not exactly how GPS signals work, and with good reasons. But it is the first documented seed of the idea of satelite based navigation that I am aware of. Source: https://secwww.jhuapl.edu/techdigest/Content/techdigest/pdf/V19-N01/19-01-Guier.pdf https://secwww.jhuapl.edu/techdigest/Content/techdigest/pdf/...