Human error, bad weather and ineffective ground radar can all have serious consequences for airport safety, increasing the risk of an accident. However, new complementary airport safety systems promise to prevent such incidents in the future.
"Though technology has come a long way towards improving airport safety, current systems using ground radar or cameras to detect aircraft and other vehicles suffer from deficiencies," says Haibin Gao, a researcher at Saarland University in Germany. New, more efficient and more accurate systems are needed to prevent accidents, especially as the world's skies and airports buzz with an ever-increasing number of commercial and private aircraft.
Saving lives is the central goal of safety improvements, but there are also significant economic benefits. Reducing the number of near misses between planes, and between planes and ground vehicles – thousands of which occur worldwide each year – would save airlines and airport operators billions of euros in lost efficiency. By being able to pinpoint the exact location and course of an aircraft or vehicle, airports would be able to maintain current capacity even during periods of poor visibility.
AN ALTERNATIVE TO GROUND RADAR?
So what are these technologies, and just how much will they improve safety? "They are all very innovative and they are likely to have a vast impact on the future of air traffic control at airports," says Gao, who is developing magnetic sensors to detect and track aircraft in the IST project ISMAEL. "They could even be a cheap alternative to ground radar."
Two IST projects funded under the EU's Sixth Framework Programme, AIRNET and SAFE-AIRPORT, are applying emerging technologies to reduce the risk of accidents on the ground and during takeoff and landing, opening the door, through their collaborative efforts, to multi-sensory detection, tracking and identification systems for planes and ground vehicles. The projects expect to have commercial products on the market within two to three years.
ISMAEL is developing arrays of magnetic sensors to detect the slight influence on the Earth's magnetic field of the metal body structure of aircraft and ground vehicles, allowing their exact location to be pinpointed.
AIRNET is using wireless technologies and the EGNOS satellite positioning system – a precursor of Galileo – to communicate with transponders on-board aircraft and vehicles to identify and locate them, with an accuracy of up to 7.5m, thus providing air traffic controllers, airport operators and managers of fleets of ground vehicles with a comprehensive overview of all airport movements.
SAFE-AIRPORT, meanwhile, is developing phased array microphone antennas to pick up the engine and the aerodynamic noise of aircraft up to 6nm in the air or on the ground, allowing them to be tracked and identified.
"The complementary nature of the three projects is obvious" explains AIRNET coordinator Franck Presutto at M3 Systems in France. "AIRNET is focusing on tracking aircraft and ground vehicles equipped with transponders, but it can't detect vehicles that lack transponders. That is where ISMAEL comes in, because it can locate non-cooperative vehicles, while SAFE-AIRPORT tracks approaching aircraft with high accuracy, which would also benefit ground management. We are possibly looking to combine all three systems into something that could ultimately replace ground radar."
To date, ground radar, or surface movement radar (SMR), has been employed at large airports with heavy traffic to keep track of aircraft. However, it has several disadvantages. SMR cannot 'see' around buildings, a hazard at large airports with many aircraft parking bays. Moreover, the number of radar antennas that can be installed is limited by the health risks and by the electromagnetic radiation interference they produce.
Ground radar systems are also rather expensive, leaving them out of the reach of small airports, which are forced to settle for the watchful eye of air traffic controllers or camera-based detection systems. Both of these methods, however, are prone to error and become ineffective in bad weather and low visibility.
"In Thessalonica, for example, fog shuts the airport for long periods in winter because they can't see the aircraft," says Haibin Gao, "while Frankfurt faces difficulties in monitoring parking stands due to shadowing effects."
ISMAEL's magnetic sensor system will be tested at both the small Greek airport and the large German one later this year. It will be able to detect aircraft and vehicles in fog and around buildings. The commercial variant, which is due in 2007, is expected to cost far less than ground radar.
AIRNET began testing in January 2006 at Porto Airport. The field tests campaign was completed and a full validation of the AIRNET system and services in real operational conditions concluded.
AIRNET is not limited to the surveillance, monitoring and control of vehicles and aircraft in the airport movement area. It is designed to be fully integrated with the airport operational management system (AOMS), the ATC system, handler management systems and even airport security systems.
"We can expect to see an increase in safety through shared awareness of ground movements between all controllers and operators," says Franck Presutto, "and we also believe it will increase efficiency." With AIRNET, baggage handling during bad weather will be safer and more efficient, allowing airports to reduce delays and increase capacity.
With air traffic increasing at an average rate of 6% a year, airports, both large and small, are feeling the strain of managing more and more planes. Meanwhile, the expansion of existing airports and the construction of new ones is becoming less feasible due to environmental concerns. The solution is to give airports the ability to handle more aircraft, and to do so safely.
This could be achieved by improving the use of available ground and air space, while at the same time reducing the risk of accidents. The SAFE-AIRPORT acoustic system, the first to employ phased array microphones in civilian aviation, will provide these benefits by alerting controllers if a plane deviates from its flight path.
"Because they do not produce electromagnetic radiation or noise pollution, multiple arrays can be used to detect aircraft from their engine and aerodynamic noise with very high precision," explains Alessandro Ferrando, SAFE-AIRPORT coordinator at D'Appolonia in Italy.
"Also, unlike radar, they can detect the composite, non-metallic bodies that are likely to be used widely in civil aviation in the future." What's more, the system costs of these technologies will be within the range of small airports, thus improving safety and augmenting capacity in a sector seeing constant growth.
All three projects plan to maintain their collaboration, and all expect their systems to have a major impact on aviation safety and airport capacity. It could contribute to future ATM systems, by suggesting solutions to the limited collaborative planning and limited facilities for real-time information exchange between ATM and aerodrome-operating authorities, in line with some components of the International Civil Aviation Organisation's Global Operational Concept.
The three projects have already established synergies to develop their cooperation, and a common web portal presenting their approach is currently under construction.
"We're solving two of the three major problems facing the civil aviation sector: safety and capacity," says Presutto. "The third is security, and I think we may go on to work in that field in future projects. Then we will have a definitive solution to all the major problems facing airlines, airports and passengers, a solution the costs of which will be so low that even small airports will be able to afford it."