[hosay123]

If some condition existed that exceeded GPS intended design, you most certainly wouldn't learn of it first from some random anecdote on HN.. more likely the front page of the BBC as the transportation system instantly collapses

So the anecdote itself is noise, it's intended to show how seriously intractable a problem accurate time is, but it doesn't do that, instead it only demonstrates OP's lack of familiarity with GPS and willingness to regurgitate corporate old wives' tales

[joshuamorton]

A single satellite mildly misbehaving on occasion won't necessarily cause catastrophe. You're normally connected to more than the requisite 3 satellites anyway, so you might notice less accuracy, but not anything terrible.

Most of these systems are designed to work if you lose GPS entirely, so they fail gracefully.

Planes won't actually fall out of the sky if GPS makes mistakes. That's y2k fearmongering.

Why is it hard to believe that a group using GPS for a unique purpose has unique needs and detect unique issues?

[cloudwizard]

https://www.bbc.com/news/technology-35491962

Could this be it?

[skrebbel]

Sub-millisecond flaws in GPS would make the transportation system collapse? Why?

[ihattendorf]

Here's an interesting article[1] about how relativity affects GPS satellites. The clock ticks in a GPS satellite need to be accurate to within 20-30 nanoseconds for accuracy, and they tick 38 microseconds/day faster to account for relativity.

[1] http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps....

[dleslie]

Triangulation of location is bounded by the accuracy of those clocks.

1 microsecond is 300 meters of error.

[ninkendo]

Precise geolocation relies on extreme time accuracy (the story always being that relativistic time dilation effects with the difference in gravity on the surface vs LEO must be accounted for), so yeah, it wouldn't surprise me one bit that the accuracy required is on the order of much less than a millisecond.