[ntp:questions] Start of new GPS 1024 week epoch

Rob nomail at example.com
Sun Aug 11 12:38:34 UTC 2013

A C <agcarver+ntp at acarver.net> wrote:
> On 8/10/2013 23:44, David Taylor wrote:
>> Today is the start of a new GPS 1024 week epoch - see:
>>    http://adn.agi.com/GNSSWeb/
>> Folks with really old GPS units are reporting problems, those of us with
>> current millennium GPS receivers should be OK, though.
> I must not be reading the page correctly but it's showing that the 
> system only incremented the week from 728 to 729.  The 1024 week 
> rollover isn't anywhere close according to that calendar.

Probably there is some software around where the manufacturer
saw a problem coming when the week number was around that value,
and implemented a simple "if week is above 728 then take it as
is, else add 1024" in the code.

That helped the units when the first overrun occurred, but now
it causes problems.

It is like the familiar "if two-digit date is 8x or 9x then take
as 198x or 199x, else take as 20xx" that was often implemented when
the year 2000 problem was "fixed".
That will cause trouble at the end of the century as well.

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