[time-nuts] Thunderbolt GPS rollover

[paul swed]

Interesting to see

On Thu, Jun 7, 2012 at 6:34 PM, Azelio Boriani <azelio.boriani at screen.it>wrote:

> So we must find a way to upload a new firmware for the TBolt before the
> 2017... that is download the actual firmware (3.00) correct the bias and
> upload the corrected one.
>
> On Thu, Jun 7, 2012 at 10:48 PM, David McGaw <n1hac at alum.dartmouth.org
> >wrote:
>
> > Not true.  GPS week is imbedded in the GPS data.
> >
> > David
> >
> >
> > On 6/7/12 4:39 PM, Mark Sims wrote:
> >
> >> Most GPS receivers base their rollover point from their data of
> >> manufacture/firmware creation/etc.   The week rolls over 1024 weeks
> after
> >> that.   They tend to not be dependent upon when the actual GPS week
> rolls
> >> over.  Better receivers have ways of inferring the actual week after a
> >> rollover occurs...  it appears that the Thunderbolt does not do this.
> >> Also,  most GPS receivers do not cease to work after a rollover...  they
> >> just report a bad date.
> >>
> >>  From the Thunderbolt manual:
> >> The first week number roll-over will occur as August 21, 1999 (GPS)
> >> transitions to August 22, 1999 (GPS). The ThunderBolt adjusts for this
> week
> >> rollover by adding 1024 to any week number reported by GPS which is less
> >> that week number 936 which began on December 14, 1997. With this
> technique,
> >> the ThunderBolt will provide an accurate translation of GPS week number
> and
> >> TOW to time and date until July 30, 2017.
> >>
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> >
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