[time-nuts] GPS Weekly Rollover Fail

[Bob kb8tq]

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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