Hello,
We have verified with the GPS chip vendor that the issue indeed was the GLONASS days since Leap Year rollover that rolled over at 00:00 Moscow Time since 2020 is a leap year.
By now, most devices may have automatically recovered from the incident, but if any issue is persisting, a reboot is the required recovery mechanism. This can be done via the AP if the AP is providing the power to the UGPS/cnPulse.
It only affects devices with firmware AXN_5.1.1 and has also impacted PacketFlux devices that utilize the same chip and firmware. If you use any of those, please work with PacketFlux on the recovery.
For cnPulse and UGPS, we are working with the GPS chip vendor to further identify firmware root cause and will determine next steps as we go forward. For now, on devices running AXN_5.1.1, we can expect this issue to reoccur on the next Leap Year rollover event which is 00:00 Moscow Time, Jan 1 2024 as well as following leap years.
For further updates on this topic, please follow the thread here: http://community.cambiumnetworks.com/t5/PMP-450/GPS-Sync-Loss/m-p/113517#M8891