Lost in space

This shift from ground aids to satellite-based navigation has been underway since 1995 and has included approvals for en route and non‑precision approach navigation as well as more sophisticated uses such as the GBAS (ground-based augmentation system) GLS landing system for all six runway ends at Sydney and multiple, specially-authorised, required navigation (RNP) approaches around Australia and overseas.

GPS – or to use its generic GNSS label – is also the fundamental building block for the radar-replacing ADS-B (automatic data surveillance – broadcast) system, that now provides a five-mile ATC separation standard across the entire Australian continent.

The US FAA was first to realise that while GPS is an excellent system (and has operated without interruption for over 20 years) its level of accuracy is limited by its design and interaction with the environment within which it operates. For example the ever changing ionosphere accounts for the biggest error, at times up to 30m. This makes GPS alone unsuitable to provide precision lateral or vertical navigation without some form of augmentation.

WAAS, or the wide area augmentation system, was deployed in the US in July 2003 to overcome these limitations and now provides some 4,000 approaches across the US, Canada and Mexico. It has become the primary Category I landing guidance system in the US replacing ILS, allowing localiser performance with vertical guidance – LPV – approaches down to 250 or 200ft minima.

SBAS, or the satellite-based augmentation system has now been accepted by ICAO as one of the three fundamental augmentation technologies for GNSS.

Many other states have now deployed or are deploying SBAS around the world. While aviation provided the primary impetus for SBAS development, that industry is now a minor user of the system and its advantages are now recognised across an expanding user base. The European SBAS (EGNOS) publicly lists the users of the systems as being aviation, road, agriculture, mapping, maritime, construction and engineering and location-based services. SBAS also provides enhanced timing services for use in the finance and power industries and is now a fundamental component of many states’ positioning, navigation and timing (PNT) infrastructure.

With current and planned SBAS deployment worldwide, Australia could soon become the largest landmass in the world that is not served by at least one SBAS. This has considerable economic consequences through reduced efficiency in aviation, maritime, rail, agriculture and finance industries.

More significantly the lack of a national SBAS will expose Australians to increased levels of risk, particularly in the transport sector. Most imported systems (including all cars from 2017) will be designed as if they are operating in an SBAS environment. Road, rail, ship, aircraft and agricultural vehicles with integral, inbuilt intelligent transport systems (ITS) will not operate to the efficiency and safety parameters they have been designed to if SBAS is not available.

Recognition of the importance of innovation has become fundamental to Australia’s continued economic development and is a major plank in government policy. Despite earlier government studies recommending an updated review, at this time there is no publicly-announced plan to even consider the establishment of an SBAS in Australia – an innovation, judging from developments overseas, that would provide economic and safety benefits that far outweigh the relatively small investment required.

SBAS has been discussed at Australian Strategic Air Traffic Management Group and the high-level Aviation Policy Group and there has been a proposal for a limited trial system to be deployed. While SBAS systems are already functional around the world, the apparent lack of progress in deployment in Australia indicates that such a trial could provide an excellent basis for not only raising public and institutional awareness, but also providing the building blocks both intellectually and technically for the development of a mature system.

The time has come for the Australian Government agencies, particularly the Department of Industry, Innovation and Science, to seriously and publicly consider SBAS funding and development as an integral part of the innovation program.

SBAS would provide economic and safety benefits that far outweigh the small investment required.