Magnetic sensors help manage airport traffic
Airports in Germany and Greece are testing a system that uses tiny fluctuations in the Earth's magnetic field caused by passing aircraft to improve safety
The European researchers who developed the system as part of the EU-funded Ismael project claim that arrays of cheap detectors which monitor the 'magnetic fingerprint' of planes' metallic bodies can pinpoint their location in places where alternative techniques have difficulties.
According to project leader Haibin Gao of Saarland University, tests at airports in Frankfurt, Saarbrucken and Thessaloniki have detected all passing aircraft, and in three-quarters of cases traced their location to within 7.5 metres ̵1; a level of accuracy comparable to most existing air traffic management systems.
Unlike the most common ground-based monitoring systems in use today, however, detecting changes in the Earth's magnetic field lets users 'see through' obstacles such as buildings and the fingers of airliner parking bays which create areas of shadow for radar.
Another key advantage is Ismael's ability to monitor planes in poor weather conditions.
"Thessaloniki airport has a major problem with fog, so bad in fact that it has to close for part of the year because air traffic controllers can't see the aircraft at the end of the runway 2km away. In the tests, the Ismael system showed it can solve that problem," Gao explained.
While large airports would use Ismael to complement existing traffic management technology, it could provide smaller sites with an affordable way of installing a comprehensive monitoring system. The sensor units are expected to cost several hundred euros each and although they could be installed along the whole length of a runway, just a few located at entry and exit gates and other key areas would be sufficient to boost safety.
The system is still operating on an experimental basis at Frankfurt and has attracted interest from airport operators around the world. However, the cost of components and the safety certification process mean it is likely to be several years before it is used commercially.
Gao believes the technology need not be confined to runways and docking bays. "During the course of the project, we saw the potential to use this system in crowded airport parking lots to monitor car traffic and let drivers know where unoccupied spaces are available," he said.
And because systems used in parking lots do not have to meet the same high safety and reliability standards demanded of airport systems, the Ismael technology could start being used in that context much sooner.
Image: The concept of magnetic fingerprints could improve airport safety