There is a “GPS week rolover” patch available at https://source.sierrawireless.com/resources/airprime/software/airprime-em_mc-series-gps-week-rollover/.
Although the rollover issue occurs on 6th April 2019, the page states that devices won’t be affected until Nov 2019.
Does anyone know why there is a difference in those dates? We have a large number of these devices in use and are trying to determine with greater certainty when they will truely be affected by the rollover.
Bevis
where do you see “the rollover issue occurs on 6th April 2019”?
This is detailed on mony many places on the web, for instance here:
The GPS week is stored as a 10bit number, meaning it rolls over every 19.7 years, the next one will be 6th April 2019.
I don’t see such date mentioned here:
https://source.sierrawireless.com/resources/airprime/software/airprime-em_mc-series-gps-week-rollover/
The difference has to do with the underlying calculation.
The April 6, 2019 date is the 10 bit field (1024 week) rollover date.
On the MC7304, an additional field to is used to calculate the GPS week.
This is a "Minimum GPS Week" that is used together with the “GPS Week” to determine the current week.
The value for the affected modules is 1054.
The difference between the two values is 30 weeks, hence the later date: Nov 3, 2019.
The correction is actually to update the “Minimum GPS Week” value to 1738, pushing the rollover date to Dec 12, 2032.
That’s very useful, thank you!