Re: Galactic positioning system
If you recall the Pioneer and Voyager plaques, a visual representation of the non-random blips of certain pulsars were included for that very purpose - to locate Sol System for the hypothetical finders.
It didn't, as I recall, account for the gradual winding down of those beacons - but as aids to interstellar navigation go, 'twas a clever first use of the "GPS".
E'
