[time-nuts] GPS Weekly Rollover Fail

[Tim Shoppa]

This will be my Z3801A's second rollover and its third 1024-week epoch.

Is there any pre-1980 GPS equipment still out there that will be undergoing
a third rollover and fourth 1024-week epoch?

Was the 1978-1979 Block 1 GPS usage, using a different base date, or were
there more fundamental changes in 1980?  The Block 1 birds were still in
use in the 1990's.

Tim N3QE

On Wed, Feb 6, 2019 at 8:18 AM Bob kb8tq <kb8tq at n1k.org> wrote:

> Hi
>
> One would *hope* that everybody making multi GNSS modules would be cross
> checking
> and taking care of GPS rollover that way. It’s always nice to see them
> explicitly stating
> that they are doing it.
>
> Bob
>
> > On Feb 6, 2019, at 12:57 AM, Michael Wouters <michaeljwouters at gmail.com>
> wrote:
> >
> > BeiDou, Galileo and GLONASS all broadcast UTC time of day (or thereabouts
> > for GLONASS - it's offset by the timezone for Moscow) so any multi-GNSS
> > receiver has a sanity check on UTC calculated from GPS.
> >
> > Michael
> >
> > On Wed, 6 Feb 2019 at 11:03 am, Bob kb8tq <kb8tq at n1k.org> wrote:
> >
> >> Hi
> >>
> >> From what I can see, you can send it a command that puts a new “oldest
> >> date”
> >> number into flash. Since it also tracks Glonass and Galileo, that will
> >> stretch out the
> >> time before you *need* to do something (like into the next century).
> They
> >> also have
> >> the “no dates before the firmware was issued” check.  There may be other
> >> date
> >> checks in there. Those are just what I’ve found so far.
> >>
> >> It also is likely that the “new” GPS sats will be flying within 19
> years.
> >> That will add
> >> more bits to the GPS time fields. Who knows if the “modern” modules
> >> already handle
> >> those bits or not ….
> >>
> >> Bob
> >>
> >>> On Feb 5, 2019, at 5:23 PM, Hal Murray <hmurray at megapathdsl.net>
> wrote:
> >>>
> >>>
> >>> kb8tq at n1k.org said:
> >>>> The F9P has multiple cross checks, traps, and even a user configurable
> >>>> “oldest  possible date” entry.
> >>>
> >>> Neat/thanks.
> >>>
> >>> Is that stored in flash, or lost on power cycle?
> >>>
> >>> If it's in flash, I can "fix" things for another 20 years by extracting
> >> the
> >>> device from its box, taking it to a bench setup, running a flash-update
> >>> program, then reassembling things.  As ugly as that is, it may be
> >> simpler than
> >>> updating the firmware in the box.
> >>>
> >>>
> >>> --
> >>> These are my opinions.  I hate spam.
> >>>
> >>>
> >>>
> >>>
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