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Historically ships at sea could determine latitude through sun-sighting or stars, but longitude was impossible because they did not have a clock which was accur
by SJC_Hacker 2y ago
Historically ships at sea could determine latitude through sun-sighting or stars, but longitude was impossible because they did not have a clock which was accurate enough
I doubt they're navigating using the sun an stars, but if the airspeed indicator is accurate, and you know you're heading, all you need is an accurate clock to determine absolute position since the last known good position.
- Dylan16807 2y agoBut quartz is accurate enough for that, let alone a properly calibrated oscillator. So why is the article focused on giving planes atomic clocks?
- turnvilis 2y ago> if the airspeed indicator is accurate, and you know you're heading, all you need is an accurate clock to determine absolute position Airspeed gives speed relative to the air, not the ground. To compute ground speed, you also need winds aloft, which can be huge if the aircraft is operating in the jet stream. Getting good data for winds aloft is difficult because there are a relatively small number of actual measurements, and everything else is model output with all the usual caveats.