New Thinking on UAS Traffic Management

Back in 2015 at the Air Traffic Control Association’s annual meeting, I heard a presentation by Google’s Dave Vos on small unmanned aerial systems (UAS), writes US industry expert Bob Poole.

To the surprise of most of us in the room, he did not propose somehow extending the FAA air traffic control system down to ground level to manage thousands of small UASs. Instead, Google’s vision was that those flying below 500 ft. above ground level would interface with multiple local airspace service providers. Those providers would register the vehicles, interface with ATC when/where necessary, provide users with airspace data, and keep the UASs from colliding or intruding into restricted areas.

In the three years since then, that approach has become the mainstream view. NASA continues to work on concepts for UAS traffic management (UTM), and the FAA has begun contracting with multiple providers of Low Altitude Authorization and Notification Capability (LAANC) services called USSs (UAS Service Suppliers). The first two USSs approved by the FAA were AirMap and Verizon’s Skyward. LAANC is considered a precursor to an eventual NASA-developed UTM.

But the field is wide open for fresh thinking on what UTM should consist of. MITRE is doing research on various communications and surveillance concepts and has concluded that ADS-B will likely be unable to handle huge numbers of small UASs due to co-channel interference. It is looking into the possible use of 4G or 5G wireless communication for low-altitude surveillance, but says that some kind of UAS-to-UAS surveillance will be needed for UAS operations above 500 ft. and below about 2,000 ft. That may be the airspace targeted by air-taxi UAS operators.

The most interesting approach I have seen is the Altiscope Blueprint—a proposed UTM roadmap developed by Airbus’s Aoperation in Silicon Valley. It begins with the premise that between urban package delivery and air taxi services, the UTM system below 2,000 ft. must be able to cope with huge numbers of UASs—e.g. up to 11,000 flights per hour of UAS air taxis during peak periods in large urban areas.

As outlined by Graham Warwick in Aviation Week (Oct. 1-14, 2018), Altiscope suggests two sets of rules, analogous to conventional aviation’s VFR and IFR. They would be Basic Flight Rules (BFR) and Managed Flight Rules (MFR). The former would be based on self-separation, in which UAS operators take full responsibility, but this will be possible only in low-density areas. MFR requires flights to coordinate their trajectory with a (not the) traffic management service.

In high-demand (especially urban) low-altitude airspace, flight corridors will need to be defined, each managed by a single traffic service. Regulators would certify providers of “microservices” such as flight tracking or fleet management. A detect-and-avoid (DAA) capability for UASs would serve as a backup to the traffic management services, much as TCAS provides a backup to prevent collisions that ATC has failed to prevent.

Finally, the Blueprint envisions progress occurring at various levels, defined as follows:

  • Level 0: visual line-of-sight UAS operation, no automation.
  • Level 1: basic detect-and-avoid to enable beyond-visual-line-of-sight operation.
  • Level 2: autonomous beyond-visual flight in low-density airspace.
  • Level 3: conditional automation, with BFR and MFR plus DAA, to permit some flights into controlled airspace.
  • Level 4: high automation, with certified autonomy, fleets that self-coordinate, and corridor control services in high-density airspace.
  • Level 5: on-demand operations in high-density airspace, with UASs certified for all phases of flight.

The Blueprint is visionary, and may or may not be what actually evolves. But it exemplifies the consensus that traditional air traffic control will not be extended down to very low altitudes. Rather, various companies will provide traffic and coordination services for specific locations and levels of operation. And if these ideas prove themselves at low altitudes, might they eventually inspire new models for air traffic management at higher altitudes?

Airbus’s A3 tells Air Traffic Management that the Blueprint for the Sky: The Roadmap for the Safe Integration of Autonomous Aircraft represents months of careful analysis by Airbus on the future needs for the airspace, the widespread impact of its forthcoming changes, and the development of the tools required for its enablement.

The Blueprint is Airbus’ vision for UTM including stakeholder roles, air traffic configuration, and system architecture. It has been reviewed by a number of independent parties, including representatives from IATA, NATCA, GUTMA, the World Economic Forum, and the New Zealand Ministry of Transport.

It is significant because one of today’s biggest industry challenges is the number of new types of autonomous aircraft being introduced, such as drones and air taxis. For example, in January of 2018, the FAA announced it had registered one million drones in the United States alone, with three million forecasted having been shipped worldwide in 2017. While the public benefit could be massive from the use of these unpiloted systems, there is currently no infrastructure equipped to accommodate them and as the number of aircraft in our skies continue to increase, we need systems in place to safely and efficiently manage this traffic.

Additionally, there is no consensus on what the airspace of the future will contain and what change is necessary. Some players are more aggressively pushing new applications – Amazon for delivery, or Uber for UAM. However, there is no real comprehensive vision from the perspective of a player that can effectively serve all markets (like Airbus). And there’s very little public data that shows the significant volume of traffic that we will likely see even at very low market penetration.

Governments and industry professionals around the world have initiated efforts across a variety of countries and regulatory agencies. While these efforts are each highly individualized (each region uses different terminology and structure), their architectures, underlying principles to unmanned traffic management (UTM), and overall approaches are actually very similar – each one consists of systems run by regulatory authorities, independent service providers, data providers, operators, and aircraft. While this step is positive, it is necessary to unify and harmonise these systems in order to ensure vehicles, and technology built for one region will be interoperable across regions – and that’s where the Blueprint comes in.

The Blueprint is designed to catalyse collaboration as well as to educate and spark informed discussions between all stakeholders. Its goal is to align readers across the industry, creating an understanding, at a high level, of the actions needed to realise a fully autonomous sky. By formulating standardised rules, procedures, and nomenclatures The Blueprint is intended to encourage innovation, ensure safety, maximize market potential, and speed up both the adoption and integration of autonomous systems worldwide. It is not a standalone document, but instead, serves as a public unveiling of what Airbus has determined, and a foundation from which we can publish more content or become more involved publicly.