"All" you need for a stellar GPS is a group of satellites (maybe 6-12) flying on VERY EXACTLY KNOWN orbits around the sun (maybe at a radius of Saturn?) and very precise clocks on them. By comparing the incoming clock-timestamps of at least 4 satellites you can calculate your position (based on your knowledge of the orbits).
So if you want centimeter precision, thats how good you need to know the current position of the satellites
(FTL makes is more difficult because the time differences become smaller)
{edit}
Pulsars are clocks as good as atomic clocks... they just do not send binary encoded timestamps. *G*
So if you want centimeter precision, thats how good you need to know the current position of the satellites
(FTL makes is more difficult because the time differences become smaller)
{edit}
Pulsars are clocks as good as atomic clocks... they just do not send binary encoded timestamps. *G*