TECHNOLOGY
The concept sounded great, the benefits
attractive, though with the traditional role of
ANSPs being to deliver this kind of change,
the threat of a disruptive technology
company entering the ATM market
prompted some focussed work by NATS to
lead the operationalisation and deployment
of this new technology within the ICAO
regulatory arena to assure that ADS-B
deployment within the critical North
Atlantic (NAT) Airspace artery was
supported by the ICAO North Atlantic
Systems Planning Group (NAT SPG).
By early 2012 NATS and NAV CANADA
led the development of a vision for 2025 that
saw the planned deployment of LEO
surveillance within NAT airspace. At a
detailed level, substantial work was necessary
to create a strategy and concept of
operations; new longitudinal and lateral
separation standards and to develop the
benefits and business case to gain industry,
customer and regulatory support.
NATS delivered this change via a project
named TELSTAR, the name being a nod to
the transformational role that one of the first
satellites played in enabling such
transformational change in so many aspects
of our modern day lives.
A simple concept
NATS’ Concept of Operations, strengthened
through close cooperation with NAV
CANADA and in turn the ICAO NAT
groups to form the NAT Concept of
Operations, was simple and followed a
similar path to that led by NATS previously
to deliver Reduced Longitudinal and Lateral
Separation minima (RLongSM and RLatSM).
This involved the acquisition and
presentation of aircraft position information
from Aireon’s ATS Surveillance System
alongside Controller-Pilot DataLink
Communications/ADS-C messages provided
by FANS Datalink. ATC procedural
clearances, and hence safe separation,
continue to be safeguarded from entry to exit
within oceanic airspace.
New flight monitoring tools, underpinned
by ADS-B data, were developed to manage
new separation standards that are now
distance, not time, based. ATM system tools
now assist the controller to determine and
maintain minimum separation between
flight trajectories, providing warnings and
alerts when minima are approached or
breached.
Whilst most tools echo what FANS
DataLink has done for many years on the
NAT, the real breakthrough is the underlying
Aireon ADS-B data. Aireon’s North Atlantic
ADS-B performance is outstanding,
updating aircraft position data as frequently
as every four to five seconds with
signal latency of less than one second,
frequently better than many terrestrial
surveillance sources.
34 AIR TRAFFIC TECHNOLOGY INTERNATIONAL 2020
NATS’ oceanic controllers are very
efficient today, frequently handling around
70 simultaneous Air Traffic Movements
(ATMs), so introducing ADS-B wasn’t
targeted at driving operational efficiencies,
that was considered unrealistic given the
Aireon’s space-based ADS-B signals
broadcast from aircraft equipped with
1090MHz ADS-B transponders