breadsmasher@lemmy.world 1 day ago
wouldn’t it be noticed immediately since space satellites would be out of sync, and GPS locations wouldnt be accurate etc?
presuming worldwide = earth
Came here to say this. Hopefully the systems in place are resilient enough to handle a leap minute (especially since they already exist), but it would definitely cause some instant issues.
The average person probably wouldn’t notice, but anyone working with time sensitive equipment would.
Do leap minutes really exist? I’ve never heard of that before? I don’t think we’ve ever had 60 leap seconds since the inception of the idea.
Its ambiguous to see how different people interpret it. My thought when I typed the question was that anything that is closer to Earth than the moon is considered part of “World Wide”, but I can see how some people would interpret satelites are not part of “World Wide”.
No what they mean is that GPS uses timestamps to calculate position so messing with time would mess with position. GPS is so precise at measuring time we need to account for time dilation due to Einstein and satellites traveling at speed.
So do we need to take time dilation into account?
1 minute forward in all reference frames? Is there an 81pSec difference in the time jump?
Yeah we need to account for time dilation but since op doesn’t specify this it would break GPS.
That wacky Einstein, still dilating time from beyond the grave.
lordnikon@lemmy.world 1 day ago
Yeah but they said all clocks so all the sats would still be in sync just like we had a leep second it would just be a leep minute.
Rivalarrival@lemmy.today 1 day ago
The GPS almanac is a table of the exact orbital information of every satellite. Every receiver needs a copy of the almanac to understand where the satellites are supposed to be, so that it can determine where it is in relation to those satellites.
When their clocks all shift one minute simultaneously, the almanac isn’t updated. Every satellite is 60 seconds away from where the almanac says it should be.
If the satellites were geostationary, receivers would still work, they’d just be off by 0.25 degrees of longitude as the entire constellation would be shifted the same amount. But the GPS constellation consists of satellites in a variety of inclined orbits. Nothing is where the almanac thinks it is, and nothing is where it is supposed to be in relation to anything else.
Parent comment is correct: GPS will immediately fail, and remain down until an updated almanac is published and distributed.
lordnikon@lemmy.world 1 day ago
Interesting so I guess they update the almanac when a leep second is preformed
DankOfAmerica@reddthat.com 1 day ago
No, the almanac accounts for the leap second since it was created. It doesn’t need to be updated.
davidgro@lemmy.world 1 day ago
The GPS ‘time zone’ does not account for leap seconds at all and is currently 18 seconds ahead of UTC. The GPS navigation messages from the satellites do however include the current offset.
Deceptichum@quokk.au 1 day ago
Satellites aren’t world wide, they’re world orbiting.
BradleyUffner@lemmy.world 7 hours ago
And even if they were included, we have clocks on Mars now that would be out of sync.