Brian Inglis wrote:
The next rollover is about April 2019, but this can happen any time
an older receiver's internal date representation used for GPS to UTC
conversion overflows. Looks like Tymserve 2100 picked about Sep 1995
for its date epoch so it hits now.
Newer GPS receivers support the extra 3 bits added to GPS extended
week allowing 8192 weeks (157 years) between rollovers - 2137 is the
next big rollover problem, but NavStar will likely not be sending the
same data on the same frequency then.
There are also GPS receivers out there which use (and have been using)
an extended week number internally instead of hardcoded limit for the 10
bit week number.
As long as there's a backup battery is OK then there's nothing to do for
the user to get the correct epoch. If the backup battery is disconnected
or fails then you can just send the current date to the device, and the
firmware computes the extended week number, including the epoch of the
GPS week number.
Martin
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
