JAM NAVIGATION
BUSTERS
As threats to GPS rise, the idea of restoring the eLoran
navigation system to act as a backup is gaining support in
the USA
David Hughes
The number of GPS outages
reported by aircrews rose
dramatically to 3,000 in Europe in
2018 and now aircraft operators and airlines
are starting to pay attention to the problem.
That is in contrast to a decade ago, when
Gerhard Berz, the senior expert for
navigation systems at Eurocontrol, said it
seemed that GPS always worked, so pilots
and international air transport associations
needn’t spend much time thinking about
potential problems. “Now aircraft operators
and airlines are starting to pay attention to
issues related to GPS outages,” he says. These
problems are often briefed now as part of the
industry’s safety oversight efforts.
“So there is quite a lot going on with GNSS
outages and we are quite busy,” Berz says.
The term global navigation satellite systems
(GNSS) encompasses several systems: US
Air Force GPS, European Galileo, Russian
Glonass and Chinese BeiDou.
Jamming consequences
The FAA says that GPS jamming and
spoofing events in the US are rare
occurrences, but that the agency has
participated in numerous GPS jamming and
spoofing tests with the Department of
Defense over the past 20 years.
Jamming is when another signal
overpowers GPS, which is easy to do since
GPS has a very weak signal – less than a
millionth of a billionth of a watt, according
to Brad Parkinson who is known as the
father of GPS. Parkinson served in the US
Air Force and as a colonel led the
development of GPS. He also founded
the Stanford Center for Position, Navigation
and Time in the USA and still consults for
the FAA.
As recently as June, NASA’s Aviation Safety
Reporting System reported that an aircraft
wandered off course and narrowly avoided
crashing into a mountain after the pilot
40 AIR TRAFFIC TECHNOLOGY INTERNATIONAL 2020