Rakhasa Wrote:I'd expect any competent Spaceman to be able to navigate without SPS. After all, you might have poured coffee into it...ECSNorway Wrote:Navigation via star-sighting, and by improvised STL SPS, are standard components of the General Spaceman curriculum (Navigation 102) at Greenwood U.Navigation via Star-sihgting and other means are more precise, but not something that your random person in the street woudl be wiling to work on. The SPS may ony be precise withing a few kilometers,or even dozens/hundreds of kilometers far away from the inhabited zones, but it will be precise enough for normal use ("We want to go to Mars" "Turn twenty decrees left"). Before GPS, you needed to learn star navigation to cross the Atlantic ocean, but not to cross the English Channel or use a rowboat.
The General Spaceman curriculum would be for the profesionals pilots in cargo and passenger transports, military ships, astronomy/space hobbists and the like.
As to accuracy, I think that depends on how much you're willing to pay. Civilian GPS can be accurate to about metre level, and if you fiddle about enough, for surveying purposes you can get it down to sub centimeter level. If you say that FTL comms is 10k 'c', and proportionally affects accuracy (this assumes you can't wave-up better clocks) first generation SPS would be good for 10km accuracy, or 100m level for survey work.
Well away from civilized areas you would have difficulty getting better than the 10km accuracy. Technical improvements are likely to give 1km accuracy, but to get much better than that you'll need to do some serious work on the clocks.
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"It is the business of the future to be dangerous" - Hawkwind