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The Maritime Administration issued one of its periodic advisories the other day about GPS and AIS jamming and spoofing. 

It included a note, as usual, about repeated reports from the eastern and central Mediterranean Sea, Persian Gulf, and the Red Sea.

2022-010-Various-GPS Interference & AIS Spoofing


The MARAD notice also included, again per usual, a link to the USCG NAVCEN problem report web page which we always find interesting.

It seemed to us that the reports posted on the site were coming from a much more varied set of places than has been the case. Lots more from South America, Northern Europe, and the U.S. 

Interesting how many are classified by the government as “unknown interference” or “insufficient information.”

We found one to be a particularly interesting account:

USER: During departure from the Tocumen International Airport (MPTO) [Panama], climbing through approximately 400 feet AGL, the aircraft lost all GPS guidance. GPS signal was normal on the ground. It was not lost until airborne. GPS guidance on iPad’s was still available. It only affected the aircraft system. The pilot returned to base and the GPS unit was replaced. On departure, it occurred again. The pilot returned to base and shifted to a different aircraft. On departure it occurred again. Speaking with the avionics shop, this issue was affecting all aircraft in the area, including airline traffic. The loss of signal seems to occur within a radius of approximately 40nm, centered somewhere within Panama City or the canal zone. This occurrence first took place Wednesday, August 17, and is ongoing.

The government’s notes on this report included the comment “Inter-agency partners confirmed known GPS interference in the area.”

The Canal Zone is five miles from the airport. Not that far for a jammer on a transiting ship to be the problem. Then again, the jammer could be in the even closer city, or somewhere along the highway that runs right past the airport. 

Here is the mystery, though. Aviation receivers are supposed to be much more resistant to interference than off-the shelf devices. Why then was the GPS on the iPad (probably part of the pilot’s electronic flight bag) unaffected when lots of aviation certified receivers were?

You just never know…