I give up, my only hope is it only effects the north.
bye bye dear Europe
I need some beer and salted nuts after that.
Believe it or not, I tried before posting, but a date and time are not much to go on, and too much else to do than spend a couple of minutes, though I did learn that UTC is GMT.
Ah well, if the world ends then at least when it happens I’ll be somewhere I’ve never been before.
I suspect it’s GPS Rollover, I don’t know much about it, but I know a man who does.
Quite a few of you got it !
GPS week rollover.
GPS provides Position, Navigation and Timing information, all or some of which is widely used in commerce as well as transport.
The system is limited with respect to numbering the week in the time element. These are numbered 0 to 1023 ie 1024 weeks.
GPS Week Zero started 6th January 1980.
The first reset was 21st August 1999
Next reset of the week counter from 1023 to Zero will be 6th April 2019.
GPS time is currently ahead of UTC time by 18 secs
So GPS week rollover will ocurr Saturday 6th April 2019 at 23:59:42 UTC
Hope you found this mega-useful and a welcome change from Brexit/Brain-teasers and Cycling Visibility 
So incredibly useful, I really don’t know what we would have done without it, so many thanks Don. I shall have people on hand to sooth the horses & told the house staff to cover the mirrors & put all the silverware into draws.
Nice to know in the end, but I suspect a totally unknown subject to most people.
But why is GPS time wrong? Is it to do with relativity and space travel? Doesn’t it have potential knock-on effects, and would be better radio controlled from the atomic clock?
IB,
Good questions.
GPS relies on Atomic clocks. The cesium clocks are very accurate and very reliable. Their accuracy might have now been bettered, but that’s what we still use. The GPS Master clocks are based in Colarado Springs (I think). And there are monitoring stations, with atomic clocks around the equator. These clocks are never “adjusted” but keep “perfect” time. However, the earth’s daily spin and annual orbit around the sun does change (the earth is slowing down). UTC is adjusted from time to time to to account for these long-term spin and orbit changes. The atomic clocks aren’t "adjusted, but simply “coded” with the number of seconds that have been added to UTC.
Each satellite in the GPS constellation has four atomic clocks. These are programmed just like the earthbound clocks re UTC, but they are also “adjusted” prior to launch to account for both general relativity and Special relativity (Gravity and Relative Speed) so should keep reasonable time compared to the master clock.
The GPS system needs to know the “time” to about a nao-second (time it takes radio waves to travel one foot). The Atomic clocks know this. Your GPS receiver doesn’t contain an atomic clock. But it does contain a computer, as well as the UHF receiver. It simply needs a minimum of four satellite signals to find a solution for three space co-ordinates (Lat, Long, “Height”) plus “time”. It updates this solution every second (five times per second if using SBAS). This means your GPS reveiver has, “in effect”, Atomic accuracy time. it just needs to add “18 seconds” to give UTC with atomic clock accuracy.
If your i-Pad contains a Sim card, or you have a modern cell-phone, you will have a gps solution system and UTC time, with atomic clock accuracy. No need for those flashy Breitling, Rolex Omega watches !
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I expect so. On the advice of a couple of chaps I met in a pub a few weeks ago (Nigel and Boris I think their names were), I contacted Chris Grayling and arranged for him to sort out all the preprations needed. He told me that he has a unique record and to leave it all in his safe hand.
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Good advice ! Just don’t travel anywhere around midnight 6th/7th April, even though Chris/Boris/Nigel say it’s all in hand !
It is safe to leave the bunker yet?
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Apparently 
Definitely.
But just to be on the safe side, I made sure that I wasn’t flying last Saturday/Sunday night.
Looks like we can all relax for another 20 years…
Ok, Ok , relax ?? what with Brexit, Global warming, Debenhams, Boeing 737 Max and The so-called Orange One, not to mention Brunai, Sudan, Yemen, Kashmir …
…relax, with Statement into those HH special, Focal Speakers …
Oh, I give up, i’m living on a permanent knife-edge with a diet of mogadons !
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My trusty ten year old TomTom satnav no longer can get a time signal from the GPS system and TomTom say it’s terminal, and offer me 30% discount on a new one…
Yep, that’s modern technology for you.
10 years doesn’t seem too bad, but I think the industry norm is meant to be 15 years, then renew.
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