Re: That's why the EU has started Galileo...
Perhaps it's time for someone to build an NTP-disciplined oscillator. :) (NTP has lots of short time yitter, but obviously no long term drift, so it might work)
It does work, sorta. The 3G femtocell devices use long sequences (2hrs or so) of NTP queries to get enough accuracy to discipline the local oscillator. My device seems to do it every 24 hours or so.
As for local knowledge, that seems to be disappearing for all the services that need it. I was talking to a coastguard officer recently & he said that his area would be concentrating to the national centre in Fareham, but that his people didn't want to move to Fareham so their local expertise would be lost.
Cheap inertial devices are getting better so they may be stable enough soon for trips of a few hours, especially with road lock to estimate the drifts. Also the nav display function 'I think I'm here. Touch the screen where I really am' would set it up for a journey.