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

David Taylor david-taylor at blueyonder.co.uk.invalid
Thu Aug 15 08:22:05 UTC 2013

On 15/08/2013 08:34, Rob wrote:
> David Taylor <david-taylor at blueyonder.co.uk.invalid> wrote:
>> On 14/08/2013 17:44, Rob wrote:
>> []
>>> How does a "good" receiver know the correct time?  Does it rely on
>>> local (backed-up) storage, or is there some way of receiving it via
>>> the almanac?  Or are "good" receivers hardwired as well, only with
>>> a different valid span?
>>> I would not be surprised when "good" receivers turn out to have just
>>> a different moment or mode of failure.
>> []
>> Some receivers have battery backup, in fact all but one of the receiver
>> types I use have this.
> Ok but what happens when the battery is replaced?

Hope and pray?  Wish for a large capacitor or flash-rom?

I had thought that either ephemeris or almanac data might contain the 
real UTC time, but apparently it does not.  Obviously a system designed 
too far in advance of the Year2000 fuss and bother!
Web: http://www.satsignal.eu

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