I have a strange issue with an FMB120, latest official firmware. GNSS is sleeping (no ignition, no movement), but every three hours reported location changes (Location is in every codec8 packet). I have configured the device to send reports every minute and it's clearly visible. Usually it's insignificant, but sometimes it's up to 100 meters. All AVLs stay the same, only location updates.
The only recent change I did was turning off the GNSS Static filter (because it was causing another issue) and this could have masked this issue.
On a first glance, the only things that happen periodically at those intervals (or intervals that multiplied could be 3 hours)
- NTP Time sync - every three hours. I'm using NITZ+NTP instead of GNSS.
- FOTA - every 30 minutes
The most likely candidate is the time sync, small drifts in RTC might change what the GPS module thinks of the location, especially when GPS is off.
My questions are:
Have anyone encountered this issue?
Is there any documentation for the TM2500 and the embedded platform/SDK/architecture available?