Reports of recurring GPS reception problems near Tacoma, WA in the US and the port of Plymouth in the UK have been received by the US Coast Guard Navigation Center, the agency that collates such reports from the public. See reports for 9/27/2018 and 10/2/2018.
The posted US government analysis of these reports is:
“The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.”
The causes for the incidents are listed as “User Equipment.”
Yet the folks reporting the problems said they have repeatedly experienced disruptions in the same locations. It may well be that their receivers are particularly sensitive to disruptions and user equipment is indeed the problem. Or it could be that many users have problems in these areas, but these two are the only ones who (a) know the procedures for reporting the problem, and (b) took the time to do so.
We wonder if it wouldn’t be a better to list “Unknown Interference” as the cause.
We also wonder if the US and UK shouldn’t investigate such reports on-scene and, as appropriate, locate and mitigate such recurring problems.