DEFENCE researchers are working with the US Air Force Research Laboratory (AFRL) to develop techniques for accurate drone navigation without the use of global positioning satellite systems (GPS).
Success in this field will have immediate benefits for unmanned aerial systems (UAS) military applications and could help develop a longer-term edge for Australian UAS applications, with the eventual goal being ‘passive navigation’ capability.
“Our aim under this project is to navigate a UAS aircraft without GPS assistance to a target location 100km away,” Australian researcher Sam Dudley said. “As part of that, to maintain range safety and for operational reasons, we need to maintain communications with the aircraft over the 100km outward journey.”
Mr Dudley specialises in trying to optimise and improve the performance of a datalink between a far-off UAS and home base.
“My work has really been examining the data link for that system and trying to keep it as reliable as possible while minimising the amount of infrastructure and complexity,” Mr Dudley said.
Mr Dudley and the team use the Woomera Test Range in the South Australian desert for these trials. The entire unmanned aerial mission must be conducted from a single launch and recovery location, to minimise the number of personnel required and to reduce infrastructure.
The team chose a flight altitude of 450m above ground to optimise safety in case of a system failure and the opportunity to capture high quality data for the on-board experimental systems.
“Reliable datalink communications are paramount to the success of our extended-range flight trials, but the trade-off we made in flying at 450m is less-than-optimal for radio communication,” Mr Dudley said.
“My paper at last year’s International Aerospace Congress presented some solutions to this problem.”
Standard testing was insufficient in predicting the performance of the datalink, as reflections from the landscape at such altitudes causes significant destructive interference in otherwise clear line-of-sight conditions. Through modelling, Mr Dudley has shown it is possible to exploit these effects in order to minimise the impact on the datalink operations.
“I presented an experimentally demonstrated solution in the paper,” Mr Dudley said.
With the datalink well on the way to being stable, the team is able to pursue its key project research focus, namely passive navigation.
“That means using available emitters, whether it be light or some other radiation source or even the polarisation of the sky to guide our UAS. In many ways we take inspiration from biology, for example migrating birds, or insects finding their way back to the hive,” Mr Dudley said.
An AFRL contingent joined Mr Dudley and colleagues at Woomera earlier this year for a successful trial, one of many such trials that have taken place.
Mr Dudley said the US defence scientists appreciated the research flexibility available at the Woomera range, and also the flexible nature of the DST auto-pilot software.
AIRSERVICES announced at the recent Wings Over Illawarra Airshow it would contribute a further $10 000 to assist the Historical Aircraft Restoration Society (HARS) complete its restoration of the Southern Cross II replica aircraft.
The Southern Cross was — probably Australia’s most famous aircraft and which now rests in a special viewing hangar at Brisbane Airport – was heroically flown in 1928 by Sir Charles Kingsford Smith and Charles Ulm to make the first crossing of the Pacific Ocean by air, touching down in Brisbane from San Francisco.
The restoration to full flight status of the Southern Cross II Fokker F.VIIb/3m tri-motor replica is being carried out at the society’s aviation museum at Albion Park Airport, Wollongong.
Airservices manager for East Coast Services Sydney, Roger Chambers, said the donation would help promote the significant contribution made by the Southern Cross and its crew to Australia’s aviation history.
“Airservices is a proud sponsor of the Southern Cross II restoration project and we can’t wait to see this significant aircraft return to the air and visit airports around the country in the near future,” Mr Chambers said.
“While we continue to support general aviation and maintain Australia’s aviation heritage, this donation is important to Airservices as it ensures that future generations can admire the feats of Australia’s pioneer aviators.”
The Wings Over Illawarra Airshow attracted more than 20 000 spectators and the Southern Cross II replica made up part of this year’s Airservices display stand and is one of the many HARS aircraft on display at the airshow.
“We are again grateful for the significant contribution from Airservices towards our restoration of the Southern Cross II,” HARS restoration manager, Geoff Timms said.
“Once the Southern Cross II returns to the skies, the aircraft will embark on a national tour to educate the nation on Smithy’s achievements.”
As part of its commitment to preserving aviation heritage, Airservices also sponsors the Civil Aviation Historical Society and The Airways Museum located at Essendon Airport.