alt Hacker News> I guess timekeeping is relatively easy...... would imagine even a standard quartz movement would be accurate enough.
Good Lord! How wrong can you get!
Very precise timing (often taken from GNSS for convenience) is needed for much of the modern word, from IP, cellular and DAB networks, to AC phase matching the electrical mains grid. Quartz clocks are nowhere near accurate enough for these purposes.
This government report makes very sobering reading: https://www.gov.uk/government/publications/satellite-derived...
TLDR: Our dependence on GNSS for timing almost dwarfs that for navigation. And we urgently need to consider using backups (be that local atomic clocks, or long wave time signals).
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> Our dependence on GNSS for timing almost dwarfs that for navigation.
Galileo satellites also now sign the timestamp (IIRC) via a Merkle tree so you know it isn't spoofed.
I mean, considering celestial navigation was a thing long before we had accurate clocks… I’d venture they aren’t wrong at all. Or did you forget that people have been doing celestial navigation by hand for over two millennia?
Some clueless downvoting here!
In the context of position keeping I think it's not too bad.
If we focus on longitude, where timing I guess matters more, the equator moves at a speed of about 0.46 km/s. So I guess being out by 1 second translates to precisely 0.46km error. That's second order compared to the stated error of 4 km, and it will be smaller still away from the equator.
I'm working off the assumption that such a drone can sync up to an accurate time source at launch, and then only needs maintain good timekeeping for its time in the air. I guess without the accurate initial time source, it gets bad. Being a minute out is suddenly 30km of latitude direction away.