The airline I work for is having this issue. The story we’re getting is that at approximately 3:00z on 6/9/19, the WAAS system on all of the GPS satellites received a software upgrade and that the software upload was somehow corrupted.
That sounds unlikely but possibly just because it's a slight misintepretation of events. It would be more likely that the software update was applied correctly but that some niche receivers either are not fully compliant to the standard or have obscure bugs in rarely exercised code which have been triggered by the new software version on the satellites. I say niche because there's likely to be testing on a decent spread of real receivers for this type of critical system.
A plausible explanation from recent Hackaday comments (
leap seconds often cause "fun"):
Josh says:
June 11, 2019 at 7:13 am This particular issue is directly related to certain GPS units from Collins Aerospace (formerly Rockwell Collins). A software design error resulted in the system misinterpreting GPS updates due to a “leap second” event. Collins has advised its customers to not power on the units until June 16, the next scheduled update by the US government to the GPS constellation.