Air traffic controllers of Deutsche Flugsicherung GmbH (DFS) monitor up to 10,000 aircraft movements in the sky while making sure that air traffic continues without any disruptions. In doing so, the controllers work on large radar screens that had established themselves many years ago. When it comes to estimating flight altitudes, however, the air traffic controllers must fall back on displays with labels, since current displays do not provide a view of the third dimension.

But that could change all of a sudden. At least that is the long-term objective of the research project that the DFS is conducting together with Cassidian, a member of the EADS Group. Additional project participants include the Deutsches Zentrum für Luft- und Raumfahrt (DLR) in Braunschweig and Christie partner 3Dims GmbH of Frankfurt, which specialises in 3D simulations.

The point of the research project is to conduct tests at individual workstations that are designed to provide air traffic controllers with a 3D model of the air space. A prerequisite for the entire system was high resolution. For instance, every aircraft was supposed to be displayed with all relevant data, as air traffic controllers are accustomed to at their normal workstations.

That means screen edges could not be blurry whatsoever and the detailed image should follow every movement of the air traffic controller's head to ensure that the controllers always have an optimum viewing angle.

To fulfil these requirements, 3Dims created a special workstation, inside of which there are two projectors aimed at two rear projection panels that are arranged at a 60° angle to one another. The projectors are subject to the following prerequisites for a high resolution system: Resolution of 1920 x 1200 pixels, active stereo support and ultra-wide-angle lenses.

Friedhelm Birk, founder and managing director of 3Dims GmbH, decided after an in-depth benchmarking study of a variety of devices to use two Mirage WU7K-M units from Christie. While projectors with WUXGA resolution deliver 7,000 ANSI lumens, they operate with reduced power which conserves the lamps and cuts operating costs. He explains: "It was especially important that the devices are absolutely flicker-free, which Christie projectors are. That can be attributed to the the 3-Chip DLP technology which is used. Moreover the customer was delighted, since he had expected that the required performance would call for installing gigantic projectors, but that was not necessary."

Christie projectors also scored points with the brightness of the image over the entire area from top to bottom. With two screens arranged one above the other, air traffic controllers inevitably have to look down at the lower display at an angle. In such cases, the displays are normally dark there. Projectors, on the other hand, deliver an evenly bright, balanced and seamless image. Birk adds: "That was definitely one of the reasons why we received the contract."

Another reason was definitely the dedication and technical expertise that 3Dims has to offer. For instance, a separate controller was built into the housing to control approximately all 20 interacting systems and to handle the activation and deactivation of all individual units. It also notes that projectors still have to run after being switched off. Moreover, a complex temperature monitoring system was integrated.

Christie projectors are cooled using an auxiliary fan that moves the hot air out of the system and away from the front side, where air currents could cause the images to flicker or flutter.
Another important point for a precise image is that the projectors are mounted in a stable and precise manner. To this end, 3Dims relies on special racks , where the projectors are mounted on aluminium plates such that they can be adjusted in three axes.

3Dims used Plexiglas as the projection panels, which were laminated with a special projection film.

Besides double projection, an active 3D stereo system is used with active shutter glasses for the three-dimensional image. A tracking mechanism, which was integrated in the shutter glasses, detects even the smallest movements of the controller's head and causes the system to react accordingly. An infrared system from Advanced Realtime Tracking is used with corresponding markers at the edge of the glasses and sensors to the left and right of the projection screens.

The objective of the project is to test such a system in order to investigate whether it would offer air traffic controllers an actual additional benefit without being a source for any additional risks. To answer this, training sessions have already been carried out and a number of other research projects are being conducted with regard to the absolute safety relevance of this topic.

For 3Dims, the project was already a complete success that required tremendous commitment. For instance, two employees spent a good month working on the design, always making subsequent adjustments in meetings and further honing the result, which was well worth the effort in any case, considering: "All parties involved have been quite impressed by the quality of the 3D projections which have exceeded all previous simulation attempts done so far", says Birks with satisfaction.