GPS Trak reporting a CPU fault to the UEM


Error

- CPU fault observed on the TRAK 9100 GPS Module Receiver.

- The fault occurs intermittently and clears automatically in some cases, but can last longer than 30 minutes.

Environment

- Product: ASTRO TRAK 9100

- Firmware Version: 

Root Cause

- The CPU fault on the TRAK system is triggered by a time jump in the 1PPS signal from the GNSS receiver.

- This occurs as a safety measure to ensure the integrity of the 1PPS timing signal sent to downstream equipment.

- The GNSS receiver may provide an incorrect 1PPS signal due to corrupted GPS almanac information downloaded from satellites.

Workaround/Fix

- If the CPU fault clears automatically after approximately 30 minutes, no further action is necessary, as this behavior indicates the internal timing realigned successfully following detection of a time discrepancy.

- If the CPU fault lasts longer than 30 minutes then monitor the unit and if it persist replace the Trak Unit

- For TRAK units prior to version 9101-15/16, a CPU fault indicates a defective module that should be replaced.