[time-nuts] End Of The World
Martin Burnicki
martin.burnicki at burnicki.net
Thu Jul 2 09:36:08 UTC 2015
Bob Camp wrote:
> Well it sounds like there are (so far) no major reports of extreme behavior. There still seem to be
> *lots* of reports of systems that do not handle things gracefully. I wonder if the data above is
> specific to a chip set (which it probably is) or to how Glonass handles leap seconds (yikes !!!).
As said in my previous email, it was a NVD8C-CSM v3.1 module
specifically set to GLONASS-only mode.
I'm assuming the problem is specific to GLONASS.
The GPS satellites sends their data frames in 6 second intervals aligned
with GPS time which is linear, with constant offset to TAI, so the data
frames are not affected by a leap second.
It's been quite a while that I looked at some GLONASS specs, but if I
remember correctly the data frames sent by GLONASS satellites are
aligned with UTC. So if a leap second is inserted or deleted there *is*
some interruption in the sequence of the data frames.
So it's much more difficult for receivers to keep tracking GLONASS
satellites than GPS satellites over a leap second, and I'm not
specifically surprised that GLONASS receiver at least loose sync when a
leap second occurs.
Martin
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