Air Transport World

Precision landings to the meter: Qantas moves forward with global landing system.(AVIONICS & SYSTEMS)

Qantas has a glo bal reputation for its extraordinary safety record for jet aircraft operations and as a leader in the development of ETOPS, FANS and more recently Flex Tracks (ATW, 4/06, p. 3). So it comes as no surprise to find that the down under airline is the first to introduce the GNSS Global Landing System to commercial service, resulting in impressive improvements in landing precision as well as significant fuel savings and noise reduction.

Australia with its vast distances, sparse population and enormous outback long has depended upon satellites for navigation. In 1994 the Civil Aviation Safety Authority, then called the Civil Aviation Authority, approved the use of global positioning satellites as a supplement to IFR en route navigation, putting the country in the forefront for regulation of GNSS technology. Further expanded approvals followed.

ICAO uses the term GNSS to represent the collective global satellite navigation capability for civil aviation applications. The core satellite constellation is the US Global Positioning System developed for military use and made available for civilian application at the end of the Cold War. The GPS constellation has been through many permutations since the first satellite went up in 1978. The European Union is developing its own system dedicated to civil use, dubbed Galileo, although it has been delayed by funding problems (ATW, 9/05, p. 54). The US and EU are working on total compatibility of the systems.

Errors stemming from satellite availability, clock errors, receiver errors and fluctuation in the ionosphere and troposphere all can affect the integrity of the data being broadcast, resulting in a cumulative error of 15 m. …

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