Collins Aerospace has received reports that certain GPS and GLU models were not acquiring GPS constellations after power up.
The impacted units known at this time are: GPS-4000S (P/N 822-2189-100) and GLU-2100 (P/N 822-2532-100).
The root cause is a software design error that misinterprets GPS time updates. A “leap second” event occurs once every 2.5 years within the US Government GPS satellite almanac update.
Our GPS-4000S (P/N 822-2189-100) and GLU-2100 (P/N 822-2532-100) software’s timing calculations have reacted to this leap second by not tracking satellites upon power-up and subsequently failing.
A regularly scheduled almanac update with this “leap second” was distributed by the US Government on 0:00GMT Sunday June 9, 2019 and the failures began to occur after this event.
GPS Week 9 Date:
(0:00GMT Sunday June 9 to 0:00GMT Sunday June 16)
It is recommended that any GPS-4000S (P/N 822-2189-100) and GLU-2100 (P/N 822-2532-100) should not be powered on during GPS Week 9.
If GPS-4000S (P/N 822-2189-100) and GLU-2100 (P/N 822-2532-100) have not been powered on during GPS Week 9, they should return to normal operations after GPS Week 9.
If any GPS-4000S (P/N 822-2189-100) or GLU-2100 (P/N 822-2532-100) units have been or are powered on during GPS Week 9, the NVM will need to be cleared before they can regain operations.
Collins is working on a plan for NVM reset in the field. The NVM can also be cleared by Collins Service Centers.