Frankfurt Airport (FRA) is the first international hub in Europe to commence regular operations of a satellite-supported precision approach system for aircraft called Ground Based Augmentation System (GBAS). A cooperative initiative of the airport, air traffic control, and the largest home-base carrier, GBAS was officially inaugurated on September 3 by Dr. Stefan Schulte, Fraport AG’s executive board chairman; Robert Schickling, DFS Deutsche Flugsicherung GmbH’s managing director of operations; and Kay Kratky, Deutsche Lufthansa AG’s member of the board Passage.
The primary advantage of GBAS is that a wide range of approach procedures can be offered with a single system. Up to 49 approach flights to different runways can be now be supported by a single GBAS station. Because of the diversity of flight approach options, there is the opportunity to develop new approach route solutions, thereby relieving noise blight for area residents. Furthermore, GBAS requires far less testing than an ILS system that has to be checked and calibrated regularly with the aid of specially-equipped aircraft.
In the long term, the new landing approach system will also be able to facilitate segmented landing approaches – with the goal of further reducing the impact of aircraft noise in the region. In the medium term, GBAS also will make it possible to introduce steeper approaches on all of FRA’s landing runways, increasing from currently 3 degrees to 3.2 degrees – up until now only possible for Runway Northwest. Along with the GBAS installation on the ground, it is necessary for aircraft to be equipped with the corresponding receivers. To first utilization potential of the system is possible with GBAS-capable aircraft types such as the Airbus A380, Boeing 747-8, 787, and 737-NG. The cost for installing and operating the GBAS ground station runs at about €5 million, while equipping the aircraft for GBAS also requires investment in the millions of euros.
For precision approach flights, GBAS provides digital guidance and works using the so-called Diferential Global Positioning System (DGPS) procedure. The new technology delivers considerable advantages compared to the existing approach procedure used at FRA. For example, satellite navigation based on the American Global Positioning System (GPS) offers accuracy within 10 meters. Furthermore, this accuracy can be increased with the aid of GBAS a ground station. Signals transmitted by the GPS satellites are received by the GBAS system on the ground, compared with its own position, and then transmitted to the landing aircraft as a corrected signal with approach coordinates. In this manner, the approaching aircraft can determine its own position with much more accuracy.
When all aircraft in the future are equipped with the corresponding GBAS onboard receivers, then GBAS will be able to fully replace the instrument landing system (ILS) technology.