Remote air traffic control

Camera system recognizes approaching aircraft

Operating a control tower is expensive. For smaller airports in particular, this can be a financial burden. This is why Rheinmetall, acting in cooperation with the German Air Traffic Control Authority and Frequentis, developed a system that enables remote monitoring and control of several regional airports from a central location.

The air traffic controller takes a final knowing look at the runway. He then clears the Luxair plane, a Bombardier Dash 8 Q400, for takeoff, indicating the wind speed and the runway. The pilot of the plane, whose destination is Hamburg, repeats the information. The air traffic controller then watches the plane, which had arrived from Luxembourg, head down the runway at full power. A perfectly normal takeoff at a perfectly normal airport, one would think – if it weren’t for the fact that the aircraft and air traffic controller were hundreds of kilometers apart. 

The aircraft took off in Saarbrücken-Ensheim. But the air traffic controller isn’t sitting in the tower of the local airport. Instead, he’s at the Remote Tower Control Center of the German Air Traffic Control Authority at Leipzig Airport, some 450 kilometers away. Yet he can see every movement on the airfield as well as approaching and departing flights on his bank of five monitors, which enable a 360° panoramic view. The central element of this “remote control” system – in operation since the end of 2018 – is an innovative camera system developed by Rheinmetall Electronics in Bremen, complete with intelligent tracking algorithms. An important advantage of this camera technology: It makes flight operations significantly safer, especially at night and in poor weather conditions or fog. This is when the cameras really come into their own, outperforming even the most eagle-eyed air traffic controller.

Better view through sensors

Andreas Löprich, project manager at Rheinmetall Electronics, explains how the system works: “Thanks to the panoramic field of view, the air traffic controller can recognize movements in the air and on the runway, day and night. 

In effect, the ATC has the same view as he would from a real tower, but with the advantage of improved visibility at night and in poor weather – in fact, better than he would have in a conventional tower. Löprich is also quick 

to point out other advantages: “If the air traffic controller wants additional details concerning the aircraft, for instance if he wants to check if the landing gear have been lowered, all he has to do is click to get an enlarged image of the aircraft. The swiveling camera automatically swings into action, homing in on the aircraft and autonomously tracking it. This lets the ATC concentrate completely on observing and controlling the situation. This simplifies his workload to an enormous extent, and the improved visibility both day and night gives an added boost to air safety.” 

It’s also important to note that the system can automatically recognize approaching aircraft in the panoramic field of view, constantly tracking them during landing and takeoff as well as on the ground, optically enlarged to assist the air traffic controller. This also applies to ground vehicles and flocks of birds, for example. The team in Bremen developed special software to enable this type of tracking, which makes it possible to recognize and automatically track moving objects based on a video stream.

Five IR pictures per second

This innovative system also features a classic light gun function, which in an emergency the air traffic controller can use to directly transmit light signals to an approaching aircraft. This light gun is integrated into the swiveling camera, which automatically tracks the aircraft and transmits the appropriate light signals. Furthermore, the ATC can select the individual zoom factor of the camera.

The swiveling camera operates hand in hand with an additional camera featuring a 360° panoramic view, likewise designed for maximum redundancy. Here, too, it’s possible to switch from a daylight to a thermal imaging camera depending on visibility. The rotating infrared sensor for the panoramic view generates five new images per second, which is unique worldwide and forms the basis for reliable object detection. In order to withstand weather conditions of every kind, the cameras are built into a heated housing, which incidentally also features a self-cleaning function. It is installed on a special camera tower near the airport tower in Saarbrücken. 

Located near the French border, this city of 212,000 on the River Saar now has the world’s second-largest airport whose day-to-day operations are controlled remotely. Plans exist for introducing the new technology at airports in Erfurt and Dresden in the coming years. Four years in the making, Remote Tower is a joint development of the Austrian technology company Frequentis and Rheinmetall Electronics, which designed the system in close cooperation the German Air Traffic Control Authority, or DFS.  As Löprich explains, “The cameras form the centerpiece here, but DFS’s enthusiasm isn’t just due to the system’s uniqueness. In the past, this kind of remote-control monitoring was limited to airports of primarily regional importance. But with over 15,000 flights a year, Saarbrücken stands out as a significant international airport. 

According to DFS, it’s possible to save costs this way while simultaneously maintaining high safety standards. The upkeep or possible replacement of an airport tower is extremely expensive. Moreover, the system leads to greater efficiency owing to significantly more flexible utilization of the ten air traffic controllers responsible for Saarbrücken – a win-win situation, which, thanks to the greater safety it results in, ought to make passengers happier, too. 

Deutsche Flugsicherung

DFS Deutsche Flugsicherung GmbH is a federally owned corporation with some 5,400 em-ployees. Its mission is to ensure safe and punctual handling of flights. Every day, some 2,000 air traffic controllers guide up to 10,000 flights through German airspace, adding up to over three million a year. The company operates control centers in Langen (near Frankfurt), Bremen, Karlsruhe, and Munich. In addition, via its subsidiary DFS Aviation Services GmbH, the company is responsible for air traffic control operations at nine regional airports in Germany as well as at London-Gatwick and Edinburgh.