12 ms·

Astral navigation is probably accurate enough

• K0balt 16d ago
  Dead reckoning with a minute or two to get a gps fix with the jammer off once a day.
  • Peanuts99 16d ago
    What's to stop someone spoofing a GPS signal during that fix?
    • K0balt 16d ago
      Nothing, and if it were subtle enough it could be effective at making it drift around. Lots of ways to get a rough fix though, and you don’t need very good absolute accuracy offshore, using a compass and log to DR your way around. Even better if you have a wind vane and anemometer. The majority of your drift will be wind driven.