Avionics News February 2020 - 20

AIR-TRAFFIC SURVEILLANCE GOES GLOBAL
Continued from page 19

Thankfully, science and entrepreneurship now offer
systems capable of tracking an aircraft literally from
launch to landing - at least for aircraft equipped with
automatic dependent surveillance-broadcast and a topmounted ADS-B antenna.
Aireon arrives:
Satellite-based surveillance here and now
Now when people hear that the Federal Aviation
Administration's new air-traffic surveillance system is
"satellite based," the phrase often lends a misconception
to the concept. ADS-B, with all its benefits, only uses
data from satellite-navigation receivers to inform airtraffic control systems with highly accurate data packages
originating from the tracked aircraft.
Satellites do not, in this case, monitor and report the
position of tracked aircraft. The aircraft's GPS navigator
calculates its position based on the GPS constellation
orbiting above Earth. The aircraft's ADS-B system,
be it a universal access transceiver or Mode S 1090ES
transponder, then broadcasts the data for the use of airtraffic controllers and other aircraft with ADS-B In or
TCAS.
The new systems include one from a company called
Aireon, with free surveillance via the Irish Aviation
Authority. This system employs the same ADS-B Out data
packets broadcast by the individual aircraft. That's where
the similarities end.
Let's examine the options available, how they work and
the equipment requirements for participation.
Eyes in space relay traffic
in the atmosphere
Aireon's website includes a resource page titled "It's
just ADS-B." And that ADS-B works similarly to the
systems put in by the FAA, the European Organisation for
the Safety of Air Navigation, the Australian authorities
and sundry other nations with a vested interest in
managing the flow of air traffic within, to and from their
respective sectors of airspace.
Here's a little background and a few questions to
resolve at the start. First, what's different? The biggest
difference stems from the link between the surveilled
aircraft and the controllers' screens.
Most people in aviation by now know that in the
United States the FAA spent years and billions building
a network of about 500 ground stations that receive the
individual ADS-B Out squawks of aircraft. Those ground
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stations receive the data packets of individual aircraft, and
the data received by those stations then moves through
a network of communications links and computers,
eventually showing up on the display screens of the
controllers and directly on the cockpit displays of aircraft
equipped with ADS-B In.
It's an effective solution to eliminating most secondary
surveillance radar from the loop for all but terminal areas
and coastal areas. Aireon's system, conversely, eschews
ground stations and instead links to controllers through
ADS-B receivers flying aboard a network of satellites
operated by Aireon's parent company, Iridium LLC.
Iridium Communications launched Aireon in 2011 as
a joint venture with Nav Canada, NATS, ENAV, Naviair
and the Irish Aviation Authority. Their goal: to develop
a global air-traffic surveillance system - one usable in
real time, around the globe and beyond the range of the
existing ground-based radar network and ground-based
ADS-B receivers.
Nav Canada invested $150 million for a 51% stake
in the project. Five years later, Aireon launched its
partnership with FlightAware to provide space-based
ADS-B services to airlines and other aircraft operators.
Qatar Airways became the launch customer.
More than three years ago, in January 2017, Aireon
launched and deployed the first of multiple ADS-B
payloads on Iridium Next satellites, each carrying
10 Aireon ADS-B transceivers as payloads. In the
ensuing two years, Aireon followed up with seven more
launches leading up to the eighth - and last launch - in
January 2019. That final launch completed the satellite
constellation and put the total in-orbit Aireon payloads at
75 satellites, 66 operational and nine in-orbit spares.
National air navigation service providers, including
Nav Canada, NATS, ENAV, IAA, Naviair, Isavia,
CAAS of Singapore, ATNS of South Africa, DCANSP, ASECNA and Seychelles all have data services
agreements with Aireon.
The FAA and Aireon
Those good with remembering dates of noteworthy
events likely recall that the FAA issued its final rule on
the adoption of ADS-B Out back in the spring of 2010,
giving operators just under 10 years to adapt and equip.
That's the significance of Jan. 1, 2020, in the U.S. - the
date controllers shifted to air-traffic surveillance using
GPS-generated data from individual aircraft instead
of transponder-derived data as reflected by secondary
surveillance radar.
Aireon, however, didn't come into existence and start
working on its now-operational satellite-receiver-based

Avionics News February 2020

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