Satellite-based precision landing systems will be essential to reduce airport bottlenecks as air traffic grows around the world.

That’s the view of Honeywell Aerospace, whose SmartPath ground-based augmentation system (GBAS) is just gaining traction after many years of development.

SmartPath has been deployed at more than 25 airports around the world, including Houston; Newark, NJ; Bremen, Germany; and Rio de Janeiro. Certification is imminent at Sydney, and at Frankfurt; Málaga, Spain; and Chennai, India, later this year.

SmartPath is the world’s only certified GBAS precision landing system, says Brian Davis, vice president for Asia-Pacific air transport and regional airlines at Honeywell Aerospace. It replaces traditional instrument landing systems (ILSs) and can save an airport $400,000 a year in maintenance costs. While each runway end at an airport requires its own ILS, a single GBAS can offer 26 different approaches and covers all runways, at a cost equivalent to that of one ILS. The approaches can be used simultaneously by numerous aircraft, allowing more efficient use of airspace through reduced separation and different glide paths.

The glide paths, says Davis, could be different for widebodies and narrowbodies, to reduce the separation required for wake turbulence.

GBAS’s ground equipment includes four global navigation satellite system (GNSS) reference receivers, a GBAS computing facility and a very high frequency (VHF) data broadcast transmitter. This ground equipment is complemented by GBAS avionics aboard the aircraft. The GBAS ground facility receives positioning data from GNSS satellites, computes error corrections and satellite health information and broadcasts the necessary information every half second to all equipped aircraft transitioning from air routes to terminal airspace. The result is positioning accuracy to within 3.3 ft down to 200 ft, a category I approach, regardless of terrain, obstacles or climatic conditions.

Davis says there is a great deal of interest in GBAS from China, “where a lot of green-field airports can leapfrog the industry.” And the aircraft are already equipped – most delivered since 2004 or so have multi-mode receivers that can be made GBAS-compatible with a service bulletin or software upgrade.