Milestone in satellite-based approach procedures

GBAS transmits digital guidance data signals for precision approaches which augment and improve on satellite data from the Global Positioning System (GPS). The accuracy of the GPS is enhanced by means of correction data and the safety of the GPS constellation is also verified. A single GBAS system provides precision approaches to all runway ends while the current instrument landing system (ILS) must be installed at each end of each runway. "GBAS will replace the traditional ILS for precision approaches in the future since it is independent of weather conditions or obstacles," says Frank Brenner, Director of the DFS Business Unit Control Centre. Eurocontrols Single European Sky ATM Research Programme as well as the FAA NextGen Programme regard GBAS as a key technology to enhance air traffic capacities. The Honeywell-manufactured SmartPathTMGBAS station in Bremen has been used in test operations since 2008 and received the Federal Aviation Administration's system design approval for regular operations in September 2009. Although additional measurements have to be carried out before the German approval can be issued, the system may already be used in instrument meteorological conditions (IMC) down to the non-precision minimum. The German certificate required for unrestricted use down to the CAT I minimum is expected to be issued in 2010. DFS is currently working on solutions to use GBAS in CAT II and CAT III weather conditions as well.