Saab is testing and operating new ‘remote control tower’ technology which will enable air traffic controllers to direct flights from remote airports without the need for a manned control tower. However, the technology may also be used to enhance operations at larger airports, as BILL READ FRAeS reports.

Örnsköldsvik Airport in Sweden is controlled from a centre 90 miles away from the airport. (Saab)

In April 2015, Örnsköldsvik Airport in northern Sweden became the world’s first remotely managed airport to be operated using a remote control tower. Aircraft movements at Örnsköldsvik are not controlled through a conventional manned control tower at the airport but by a remote tower centre (RTC) located 90 miles away at Sundsvall.

The technology to enable remote tower operations has been jointly developed by Swedish air navigation provider LFV and defence and security company Saab. In addition to the Sundsvall RTC which manages operations both at Sundsvall Timrå and Örnsköldsvik airports, Saab’s remote tower system is also being tested at other sites in Sweden. Norwegian air navigation services provider (ANSP) Avinor is trialling an RTC at Bodø to remotely manage operations at a low-traffic heliport at Værøy Airport that handles four daily flights, as well as at Roest airport. Remote operations are also being tested at Linköping Airport.

The system is also being tested at other locations around the world. In 2015 Saab signed a contract with the Irish Aviation Authority for a RTC to be set up at Dublin Airport to control two remote towers at Cork and Shannon airports. The tests are due to finish in 2017, after which Irish regulators will decide if the system can be given the go-ahead. In The Netherlands, trials being conducted at Schiphol and Groningen airports, while trials have also been conducted at Leesburg Airport in Virginia, USA. In 2015 Saab conducted a non-operational evaluation at Alice Springs Airport in central Australia which was controlled from a RTC in Adelaide, 950 miles away.

Better than the real thing

The view from an RTC is very similar to a manned tower, except for a slightly compressed image.

A RTC operating room is laid out in the same way as would be found in a manned tower. Controllers are able to operate all sensors, lighting, alarms and other tower systems at the remote airfield, together with integrated flight data, electronic flight progress strips and other surveillance and air traffic management systems. Instead of windows, the RTC features a horizontal array of video screens showing panoramic real time images from 14 high-definition cameras showing an elevated view of the remote airport buildings, taxiways and runways. The camera suite includes HD video cameras, a pan-tilt-zoom (PTZ) camera, signal light gun, and microphones which transmit the sounds of aircraft taxiing and taking off. The cameras are fitted inside glass covers which are kept clear from rain or condensation using compressed air. “If one camera fails then it can be replaced by another,” explains Per Ahl, Saab VP, Head of Commercial, Civil Security and Traffic Management. However, an RTC differs from a manned tower in that the ‘outside view’ is compressed so that more visual information is fitted into a narrower field of view. “We can fit 360deg of view into 222deg of screens,” says Ahl.

Moving objects can be detected and identified. (Saab)

The view from the RTC window also differs from a manned control tower in that the screens can be enhanced with a number of additional visual overlays. These can include infrared images which can show details of the airport during hours of darkness or bad weather conditions.

A drone detected at night.

The systems can also detect moving objects across the airfield or in the sky and highlight them on the screen inside a target box. These can include not just aircraft but also moving vehicles and even people. The system can also detect small moving objects, such as birds and also drones. If the moving object is identified, it can be labelled. An alert can also be given to the controller whenever an unidentified object is detected. “The system can be used to enhance airport security by detecting unauthorised intruders or UAVs which are flying too close,” said Ahl.

Metrological sensors can also transmit information on wind and weather. All the data from the videos and sensors can be recorded in case they are needed for future analysis.

Economic advantages

A single RTC operator can oversee several airports at once. (Saab)

Saab is keen to promote the economic advantages of using RTCs to operate smaller airports. Publicity from the tests of the Leesburg remote tower claim that building or replacing a FAA-certified control tower at a US airport could cost between $4m-$9m while a remote tower system would cost a fraction of that price. There would also be cost savings in the number of personnel needed to operate the towers. RTC controllers would not have to travel to remote or weather-sensitive locations and could also direct air traffic at more than one airport. It could also enable airports to stay open longer and operate for longer periods.

Airport fixed operational costs could also be reduced by using one RTC to remotely control several regional airports with low volumes of traffic.  An RTC can supervise two or even three different airports and monitoring images transmitted from all of them which can be widened across several screens depending on which airport was currently being controlled. “For smaller airports, an RTC solution could mean the difference between it staying open or closed,” commented Ahl.

Regulatory approval

While the Swedish Transport Agency approved the RTC system for Sundsvall in 2014, the concept has not yet been approved by all the international air traffic regulators. However, Saab hopes that the various tests and demonstrations taking place around the world will show that a remote ATC system will be indistinguishable to airspace users as a manned control tower. The Sundsvall RTC passed Single European Sky ATM Research (SESAR) site acceptance testing in February 2013. The US FAA monitored the testing at Leesburg while Australian air traffic regulators followed the evaluation testing at Alice Springs.

The bigger picture

The system could also be adapted for larger airports. (Saab)

While Saab originally developed its virtual ATC application for remote airports, the company is keen to develop the technology for wider airport applications. To this end, Saab signed a contract in June with LFV to establish Saab Digital Air Traffic Solutions to market, sell, develop and operate products and services for remote air traffic control. Saab is the majority owner with 59% of shares with 41% held by LFV.

As well as being used at unmanned or limited opening hours airports with low traffic levels, the remote control tower system can also be used at major airports. “The system is scaleable,” explains Ahl. “Airports with multiple or remote runways located beyond the line of sight from the main control tower could control all their operations from one place.” In addition, an RTC operations room could be used as a back-up if a manned control tower was closed for maintenance or even in an emergency situation such as an aircraft accident or a terrorist attack. An RTC solution would also enable airports to be operated in less developed countries with limited infrastructure. There are also military and disaster relief applications where a remote tower could be deployed to a remote airstrip but controlled from a less risky location.

RTC-controlled airports also have the additional situational awareness available from infrared monitors, zoom cameras and motion sensor detection and tracking systems. They can also continue to be operated in adverse weather conditions, such as fog. These systems can also be used for training and for playback in the event of an incident.

Saab’s SAFE system for police forces could be incorporated into airport systems.

However, Saab is not stopping there and is currently looking at ways in which the RTC concept could be adapted to improve an airport’s entire situational awareness by linking together different systems used by airport users, both airside and landside. “Each airport user could access information relevant to them from a central system,” explained Ahl. “Thus, if there was a situation either inside the airport or an airside incident which would lead to flight delays or passenger congestion, information on this could be available to airline, security, baggage handling or other staff.”

Saab’s digital air traffic management system would combine and co-ordinate different airport management systems. (Saab)

Such a unified airport system could be enabled using a communications and control system from Saab called SAFE. Developed for police and emergency services, SAFE enables police operations to be co-ordinated and controlled from a central location by linking data from different sources to improve communication and situational awareness. These can include information on people, locations, resources, movement, 3D maps, satellite imagery, geofences, building schematics, heatmaps and CCTV. SAFE can also recommend particular actions or issue automatic alerts. “By incorporating platforms such as SAFE, airports would be able to not only control flights remotely but also all airport operations,” said Ahl.  

27 September 2016