AIR TRAFFIC TECHNOLOGY INTERNATIONAL 2020 45.
The FAA says that eLoran would be a
suitable backup for aviation but using it
would require all aircraft to be equipped with
new avionics which makes it unaffordable
for aviation compared to DME/DME and
VOR. However, if eLoran becomes an
operational system in the future, the FAA
says it would assess its viability as a backup
for aviation. However, the FAA also
highlights that the current reversion to
DME/ DME is seamless. Current avionics on
aircraft automatically switch to DME/DME
RNAV if GPS becomes unavailable and
aircrews currently fly RNAV arrivals,
departures and conventional airway routes.
Parkinson believes that eLoran is a cheap
insurance policy. “Granted there are no
commercial receivers right now. You need
the signal first and then you will get a user.
I’m convinced we are going to end up with
some simple augmentation to a computer
chip and it is going to cost very little. The
interfaces are going to be the same if you do
it right. It will not be as accurate. It might be
25 meters, maybe something like that.”
The USA is in the enviable position of being
one country covering a large part of a
continent. That makes it much easier to
establish an eLoran backup system. Berz
believes that establishing an eLoran system
in Europe is a nonstarter because it would
face major political and financial hurdles.
Europe did have a Loran system that covered
the British Isles and France. Stations in
Russia might still be working but
information from the country is unclear. A
new common system with continental
coverage in Europe would have to include
installations in the UK, Scandinavia, France,
all of the Mediterranean states and also
Russia among others.
However, Berz believes that if the USA
built an eLoran backup system and aircraft
started to be equipped there, the situation in
Europe could change. The maritime industry
could also be a prime mover on the system.
And these two are not the only industries
benefiting from GPS. A study released in
June by the National Institute of Standards
and Technology, “Economic Benefits of the
Global Positioning System”, identifies US$1.4
trillion in benefits from GPS over 33 years to
private industries in the USA. These
industries included agriculture, electricity,
finance, location-based services, mining,
maritime, oil and gas, surveying and
telecommunications. There are three billion
GPS receivers in use and the study estimates
a widespread outage would cost the United
States US$1 billion per day.
But eLoran would not be a panacea.
Goward says that systems engineering says
you need to have three to five sources for
something you can’t live without, so the PNT
advisory board has been advocating a multilayered
approach. A single backup to GPS is
better than no backup, but the advisory
board has advocated a balance of using GPS/
GNSS, an inertial measurement unit for
navigation, a clock for timing, and a difficult
to disrupt terrestrial signal such as eLoran.
“The government instituting a single
backup and encouraging the use of others is
the first step to a more complete
architecture,” says Goward. The foundation
he leads has also approached the US
Government about establishing a more
complete system for detecting and warning
mariners and other users about GPS
disruptions around the world.
“Others see us as calling the GPS baby
ugly, but we see it as calling the GPS baby
precious and deserving of as much
protection as we can give it,” Goward says.
We haven’t been doing enough to protect it
in terms of the signals and with
complementary capability that would
dissuade people from messing with GPS and
provide users some capability when GPS is
not available.” v