Making Space

News that the World Radiocommunication Conference in Geneva has allocated a radiofrequency spectrum specifically for global flight tracking now places ICAO under even greater pressure to deliver a workable framework to force every aircraft in the global commercial fleet to report its position every 15 minutes within two years.
The conference which takes place once every four years convened on Monday and was surprising for the speed with which its signatory member states backed the future technology. Space-based aircraft surveillance will greatly improve flight tracking when an aircraft flies out of radar coverage, something that was called for following the disappearance of the Malaysian Airlines Flight MH370.
Now the allocation has been made, it is expected to come into force immediately and will allow ICAO – as the UN agency which writes the rulebook by which aviation operates – to continue its work on developing future standards safe in the knowledge that the frequencies have been allocated by the International Telecommunication Union, its UN communication technology counterpart.
That will be welcomed by businesses such as Aireon, developer of the world’s first space-based global air traffic surveillance system. Its satellite-based ADS-B system promises the potential of near real-time position reporting and as such offers the prospect of huge safety, efficiency and search and rescue gains for airlines flying through remote airspace.
Aireon technology will be carried on the Iridium NEXT constellation whose first satellite is scheduled for launch in April. The Harris ADS-B receiver technology that Aireon will be using will then start to feed back data during the early validation phases – the complete constellation will take around 18 months to deploy.
The allocation of a specific radio spectrum will therefore help businesses such as Aireon start to work with ICAO which is charged with developing the characteristics of any future space-based ADS-B system. As an early mover, Aireon will certainly have a comprehensive level of input into the agency’s initial work in developing the necessary safety standards.
The succesful securing of the allocation also poses a problem for ICAO’s eventual aim of making the tracking requirements ‘performance based’ and ‘technology agnostic’ especially in the longer term when aircraft will be required to send broadcast automatic alerts at a much faster rate as soon as it goes off course.
“If ICAO and its member states required airlines to obtain position reports over the ocean at update rates under a minute that for most aircraft could realistically only come from ADS-B avionics that would initially de facto impose the use of ADS-B transponders and Aireon satellites so the requirements would not be technology agnostic,” noted one industry insider.
Mike Thompson is co-founder and director for technical development at the Access Partnership which has provided regulatory licensing and technical advice to several of the air navigation service providers which have invested in Aireon. He tells Air Traffic Management that securing the allocation represents a highly important ‘gateway’ for ICAO to begin move into standards development with confidence.
“The Aireon system will be fully functional by 2018 and Aireon would be fully expecting ICAO to have the standards in place by that point,” he said.
Thompson has always been fairly confident that the allocation would happen as there was a healthy degree of political will behind the move to grant the allocation. That was apparent ever since the ITU placed the issue of exploring possible changes necessary to support global flight tracking on the WRC agenda, garnering unanimous support for that decision.
At the same time, support was bolstered by the move by ICAO to fully support primary allocation for satellite-based ADS-B at the 1090MHz frequency which meant that no changes would be needed to existing aircraft equipage, something which would have posed a significant barrier to the technology’s uptake.
Still, when any new technology requiring radio frequency is introduced, the issue is invariably assigned to an ITU working party to examine.
Thompson argues that what this technology represented however was a simple tweaking of the international spectrum rule governing terrestrial ADS-B to include its future satellite-based equivalent. As such, it was never going to threaten a massive realignment of issues, rather an administrative adjustment to the allocation.
And while ITU studies judged that no new transmissions would be created and therefore no interference risk created, it did have to study what satellite-based ADS-B would have to live with. Studies were completed in a relatively short time taking barely more than a year to accelerate once the ITU had announced its support last year.
While they concluded that space-based ADS-B could co-exist and would require no new adjustment to existing secondary surveillance radar technologies, the issues really revolved around this: how much protection would such satellite based systems require? Would they need protection from the existing aviation networks – such as secondary surveillance radar that were already out there?
“That issue really is one for ICAO to determine: how space-based ADS-B would be protected against other terrestrial systems,” said Thompson, adding, “although it does in fact complement the existing terrestrial system extremely well.”
Thompson reports that regional positions adopted at the WRC demonstrated that most were largely comfortable with the inclusion of space-based ADS-B within the band and few concerns over any impact on secondary surveillance radar systems due to the fact that the two technologies are optimally employed in completely different geographies.
With the securing of the radio spectrum allocation, Thompson says the Americas as a region have expressed very strong support for swift adoption as has Africa where the inception of space-based ADS-B would provide ATC in that region with a far better surveillance picture across the continent. A fair degree of interest has also been expressed throughout the eastern European region, most notably Russia’s commonwealth states.
Both UN specialised agencies are notorious for the length of time they take to develop standards for such technology advances and the unaccustomed speed that has seen space-based ADS-B ushered into the surveillance technology community has no doubt been driven by the tragedy of Flight MH370.
Even so, ICAO in parallel has still to develop its own standards framing the use of satellite-based data which will determine the safety rules by which an air navigation service provider must comply with in future.
That process has had little impact on the radio spectrum allocation considerations however. The caveats here revolved mostly around possible interference with existing aviation safety communications systems.
With the allocation secured it seems evident that those concerns have been allayed. An additional fear was that competing WRC agenda items – such as new mobile cellular telephony frequencies and use of existing fixed satellite system to control unmanned aerial systems – could have absorbed too much time and attention and have scuppered the hopes of space-based ADS-B champions. Again, evidently not.