SURVEILLANCE
that shows the location and identification
information of all aircraft and vehicles
with an accuracy of one metre,” he says.
“It is a requirement that anyone who
travels around at the airport in low
visibility must be equipped with such a
transponder so that air traffic controllers
have full control over the ground traffic at
all times.”
Long and short range
ATC and SMR radars are different. ATC
includes long-range Air Route Surveillance
Radar (so-called ARSR) that can track
aircraft up to 250 nautical miles; and
Airport Surveillance Radar (or ASR) with
a range of 60 nautical miles. ATC radar
looks up to track targets whereas SMR
looks down, and typically has a range of
about two nautical miles (three or four
kilometres). Because ATC radar tracks
targets that are far away, the update
rate may be about every five seconds,
whereas the SMR update rate must be
every second. Moreover, the two systems
operate on different bands: ATC radar
uses L, S or C band, whereas SMR works
on the X or Ku band.
Larger airports may have different
towers for air and ground movements.
On the ground, controllers can monitor
movements from towers, aided by the
radars and cameras, as well as radio
communications.
Each flight has a flight plan that includes
the routing, as well as any “reservations”
xxx
being joint use facilities in association
with the Royal Norwegian Air Force.
Thomas Østvang is a senior system
engineer with Avinor for ATC surveillance
systems, and is responsible for the three
SMRs at Oslo airport.
“We have Terma radar with Easat
antennae,” he says. “We collaborated with
Terma and Easat when we opened the
airport in 1998, and added a third radar
in 2012 when we built a new terminal and
pier here at the airport. This work was
finalised in 2017.”
All three of the Oslo SMRs are now the
new solid state versions, which require
less maintenance and operate on reduced
power. Østvang adds that the radar are
located at each runway, with one in the
centre of the airport for best coverage.
In addition to the radar, Avinor uses the
MLAT system from the Czech supplier
Era. “This is a collaborative system that
sends a signal to interrogate airplanes and
vehicles. We depend on the transponders
in the aircraft and vehicles to answer us
back,” Østvang explains.
According to Østvang, there are about
200 transponders installed in the vehicles
travelling around Oslo airport.
“The controllers have a display that
merges the data from the radar and MLAT
An overview of both the apron and
the sky is essential at any airport
needed to get the aircraft from one airport
to another. That information accompanies
the aircraft from departure gate to arrival
gate.
Controllers are focused on safety
but a busy airport must run efficiently,
especially during the busiest periods.
Taxi-ing aircraft don’t want to waste fuel,
for example, yet there are many vehicle
movements that must also be managed.
NAV CANADA is an air navigation
service provider, managing the ATC
operations as well as surface movements.
According to the spokesperson, every
vehicle will have a transponder if it goes
into the manoeuvring area. However, gate
control is under the airport authority.
“If a vehicle will not be operating
on the manoeuvring area, like a tug or
baggage cart, then it doesn’t have to have
a transponder,” explains NAV CANADA’s
Dave Ferriss, Manager of the Surveillance
More flights equates to busier ramps
and the need for constant monitoring
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