Two recent reports to the US Coast Guard document persistent GPS disruptions within seven or eight nautical miles of the Saudi Arabian port of Jeddah.
These follow well documented problems in the Black Sea, around Cyprus, off-shore of Syria, and in the vicinity of Port Said, Egypt.
Saudi Arabia has had a Loran-C navigation system in operation for decades. We don’t have any information as to how extensively it is used.
Saudi Arabia Loran-C 95% and 99% Contours
