This week has seen confusion in the US over reported failure of GPS with, on 10 June, the FAA publishing ‘Outage Summary’ maps of the country.
The problem imerged when Automatic Dependent Surveillance - Broadcast (ADS-B), used to track and identify aircraft, failed in many areas. ADS transponders use GNSS as the reference for aircraft position and height.
But, with other modes of transport unaffected, it soon became apparent that the problem did not stem from GPS itself, but from a faulty update to a large class of airborne GNSS receivers provided by Rockwell Collins. The problem is also worldwide.
The FAA has issued a temporary waiver to allow affected aircraft to fly under certain conditions, including a height restriction of FL280 (~28,000ft), using ‘traditional airways and/or navaids’.
It will be interesting to see a final report on this debacle . . further details from the RNT Foundation