Australian GNSS – A Snapshot

There is so much going on around the world in GNSS applications and developments that when we try to report what’s going on in a particular location, all we can really do is provide a snapshot. Each snapshot is simply a momentary picture captured at a single location — there really could be an entirely different picture around the next bend. However difficult this might be, it’s surely interesting to get a glimpse of things going on elsewhere, and hopefully we can capture some trends and innovations in the process…

In a continent the size of Australia, a country which is connected by so many lines of communication and commerce to so many other GNSS nations, it’s an impossible task to describe everything that’s going on, so I’m going to zoom in on an outfit I’ve known for a number of years and ask them to give me their “GNSS snapshot”.

GPSat in Macleod, Victoria (that’s at the bottom right hand corner of the continent), has been at the GPS game since 1993 and has crossed a number of applications boundaries. From initial OEM product and GNSS simulator representation through integration projects such as RTK container positioning at ports in East Swanson and Port Botany, huge open-pit excavator systems, and all the way to race horse velocity/position tracking systems — GPSat has grown in experience and capability over almost two decades of innovation.

GPSat got so deeply into integration programs that the company now offers not only products and systems, but also GNSS engineering services  or as they put it ‘Engineering Turnkey Project’ development. A deal of those projects were connected to the now defunct Australia AirServices Ground-based Regional Augmentation System (GRAS) – Australia’s answer to SBAS and to some extent to GBAS.

While the rest of the world was focusing on satellite-based and ground-based augmentation systems, Australia was stirring up interest in an alternate system that took advantage of a large number of existing ground radio systems used by AirServices for air-traffic communications along the major air-traffic routes. Other countries have similar radio infrastructures and also became interested in the GRAS concept as an alternative to the more expensive satellite GEO broadcast of data. The GRAS system was to use the same principles as SBAS/WAAS, but correction and ionospheric data was to be relayed through the existing network of ground radio stations, uplinking this data using GBAS/LAAS messages to aircraft also equipped and certified for GBAS/LAAS approach and landing. The system design eventually drew support and recognition from the International Civil Aviation Organization (ICAO) and was ready to be prototyped/fielded in Australia, when AirServices unexpectedly pulled the plug.

We won’t dwell here on the reasons that this project ended, rather on the by-products which grew out of years of GPSat’s support to AirServices GRAS program, including large amounts of data collection and processing using WAAS ground reference receivers at test installations at Darwin, Melbourne and in the US.

GPSat developed ground emulations of GRAS ground systems that could also be used for airborne testing. In advance of GRAS ground station fielding, the GVT Emulator provided engineering reference station capability for testing and data collection. The GMMReceiver provides a monitoring and validation tool using the actual VHF data-link and is still suitable for GBAS/LAAS system testing.

GMMReceiver.

GPSat also built a system which bridged PC-based commercial flight simulation applications such as Xplane or FlightSIM to drive a GNSS simulator, so that dynamic, simulated GPS signals are available to “fly” candidate airborne receivers. For anyone in GPS test engineering who has laboriously prepared static simulation scenarios, this could be a real time saver!

So, with the demise of GRAS, where will Australia go for precise enroute and approach navigation? With multiple GNSS constellations coming on line, the required integrity for air traffic management might just be satisfied by multiple constellations when used together. With approximately 30 GPS SVs (all original aviation integrity assessments were based on a Qty 24SV constellation), plus Galileo with GLONASS as a fall back, there might just be enough SVs for internal integrity assessment without external aids. This seems to be worth some investigation.

Now where would GPSat go next with all their technology and capability? “3D spatially aware machines,” you say. Well, I would never have guessed! So if you take GNSS positioning as the core, add inertial to overcome satellite outages, and use gaming software (an extension of the earlier flight simulator applications), add 3D models of the local area including other machine locations, and bring in radio communications between all the machines in the system — well, you have 3D spatially aware machines. Adding yet another twist — connect them all to the Internet via radio links and you can monitor and potentially manipulate these guys from anywhere in the world!

3D-SAM: Spatially aware machine.

This application is initially targeted at open-pit mining, where multiple vehicles and stationary ore/coal moving belts and other machines are constantly at risk of damage from collisions. The system is in use at AngloCoal for stockpile machinery primary navigation and Backup Anti Collision System (BACS).

Meanwhile, AirServices is working actively on GBAS/LAAS for aircraft approach and landing. Quantas has been landing Boeing 737 aircraft and the new giant Airbus-380 using this system at Sydney International Airport since 2006. Update/replacement of the Honeywell SLS-3000 GBAS/LAAS ground system by the US FAA approved SmartPath system is expected shortly.

Automatic Dependent Surveillance Broadcast (ADS-B) is also already operational in Australia too. ADS-B is an air traffic surveillance technology that enables aircraft to be accurately tracked by air traffic controllers and other pilots without the need for conventional radar. ADS-B uses GNSS/INS position transmitted by each aircraft, together with a ground network of radio stations, to acquire and track aircraft and provide controllers with wide area aircraft positional information. Aircraft also communicate with each other to provide pilots with their own situation awareness of other air traffic.

I would be amiss to complete this initial, limited snapshot without mentioning the other major use of GNSS in Australia — in agriculture. A typical farming operation in Australia could be on around 100,000 acres with maybe six rigs working around the clock during planting season, covering 3,000 acres a day. With these huge rigs, and other sprayers, trucks, and utility vehicles, typical fuel usage can top 10,000 liters daily! Automation is how this gets done, and automated agricultural guidance systems abound in Australia. Hemisphere, Trimble, and Beeline all figure highly in typical Australian guidance system installations with local distributors and installers covering major farming centers.

Finaly, there is also Locata in Canberra, an outfit whose LocataLites and LocataNets have drawn attention from some key players  — both Leica and Trimble have signed partnerships with the company in recent years. Locata has now figured out how to work with GPS but with a compatible ground-based system working at 2.4GHz in the existing Industrial, Scientific and Medical (ISM) band. With much higher power levels in a non-interfering frequency band and centimeter accuracy, while still working with GPS, this seems to
make for a really suitable potential candidate for GPS back-up in the event of jamming, among many other potential applications. And apparently low-cost dual mode GPS/Locata receivers could already be available. Things are brewing now that I’m not at liberty to discuss, but this erstwhile stealth-mode company will make  big noise soon.

So aviation, mining, agriculture, and even potential GPS back-up technology — just a snapshot of some of the sectors for which GNSS forms an essential component in Australia.
Tony Murfin
GNSS Aerospace