The U-Space: The Journey to Integrate UAM-UAS into Airspace

Airspace management is on a journey to integrate urban air mobility (UAM) and unmanned aircraft systems (UAS) in the airspace system. Progress is being made in
this domain sustained by a set of main drivers. Mario Pierobon spoke to industry experts to assess the progress made, see what else is needed to proceed with the integration and learn how artificial intelligence (AI) is being used in integrating UAM and UAS into the airspace.

Europe is progressing in the creation of ‘U-space’, the ecosystem that will allow UASs to operate at scale. This has been made possible thanks to a number of factors working in parallel, namely an enabling policy and regulatory framework, a strong, collaborative and inclusive research base and a highly committed industry made up of first-movers ready to deploy, explains Andreas Boschen, executive director of SESAR 3 Joint Undertaking.

Progress So Far

According to Eduardo Garcia, CANSO manager for European ATM coordination and safety, what is currently being faced is a new era for aviation. “The speed of change and rate of innovation will be faster in the next 20 years than they have been in the last decades. To safely accommodate all airspace users in our sky without congestion or increased delay requires new ways of thinking and increased collaboration,” he says. “As we look towards this new future, we can clearly see many opportunities in front of us, but standing in our way are multiple barriers, key challenges that stretch wide across our sector, and extend deep into traditional characteristics that are the by-product of legacy systems and the industry’s prestigious history.”

Andreas Boschen
SESAR 3 Joint Undertaking

Detailed technical European Union (EU) rules have been adopted in 2019 to integrate low-and medium-risk drone operations in the airspace, introducing mandatory registration of operators or the need for a risk assessment and authorization for the ‘specific’ category of operations, according to a European Commission (EC) official. “Current drone operations already take place under this harmonized framework. Rules and procedures for the management of drone traffic (U-space) entered into force in January this year and are available to Member States to manage their airspace and allow the safe expansion of drone operations,” the EC official says. “Finally, work is underway to revise the entire aviation regulatory framework to allow the highest risk operations, including the transport of passengers. The first operations of passenger drones, initially with a pilot on board, are planned for 2024.”

Eduardo Garcia
CANSO

SESAR research and innovation is allowing U-space to be progressively deployed based on increasing availability of enabling technologies, according to Boschen. “With our recently completed very large-scale demonstrations, we are facilitating the deployment of advanced services, such as detect and avoid, altitude reference measurement, and the interface with manned aviation. Within our SESAR programme, a mature concept of operations (CONOPS) covering UAM has now been developed to show the big picture and maintain coherency. UAM will initially comprise piloted vehicles with unpiloted air taxis expected to come into operation at a later stage,” he says.

Several digital sky demonstrators recently got underway as part of the SESAR research and innovation programme, and more industrial research projects are planned to start later in 2023, according to Boschen. “Together these demonstrators and industrial research projects are offering a real ecosystem with test sites in numerous regions and cities across Europe involving many regional and local authorities, who will ultimately integrate drones into their mobility policy,” he affirms. “Standardization activities are also ongoing, involving all European bodies and in harmony with global bodies; indeed Europe has a UTM Standardization Coordination Group (EUSCG) to define the future standardization requirements and roadmaps.”

Joel Klooster
Inmarsat Aviation

According to Joel Klooster, senior vice president of aircraft operations and safety at Inmarsat Aviation, while still in its infancy, the UAM UAS market has evolved rapidly over the last couple of years, and there are some clear goals and milestones the industry is working towards. “With so much innovation on the horizon, it is crucial that key players in the UAV sector work together to meet the regulatory challenges that lie ahead. The U.S. and Europe have published near to mid-term CONOPS with many different flight trials planned or already taking place, which cover various unmanned aircraft systems (UAS) integration scenarios,” he affirms. “However, this testing is still very tightly controlled, typically via waiver, exemption, or by mandating that any newly developed autonomous vehicles must fly in a wholly segregated airspace. End-state integration is managed as safely and efficiently as possible through an ongoing effort to develop standards and regulations for every facet of UAM and advanced air mobility (AAM).

Inmarsat Aviation has designed and developed Velaris, the connectivity service catering specifically for the sector. “Powered by our ELERA global satellite network, Velaris is a global, reliable, and totally scalable connectivity service supporting Command and Control (C2) for UAS. It enables everything from simple tracking and identification for small UAVs to full aero safety services for those operating in controlled airspace. Most critically, it makes it possible for UAVs to be trackable and controllable securely beyond visual line of sight (BVLOS),” says Klooster. “Also paving the way for UAVs to be safely integrated into commercial airspace is the European Space Agency’s (ESA) Iris air traffic management modernization programme, which is powered by Inmarsat satellite services. We provide secure Internet Protocol (IP) connectivity to relieve pressure on near-capacity, congested VHF radio links and deliver high-bandwidth, cost-effective satellite-based data link communications for global air traffic management (ATM) modernization. Together with ESA, we have also invested in the miniaturization of satellite communications terminal technology, allowing almost any class of UAV to be connected BVLOS.”

Drivers and Barriers

Indeed, drones are already being used as everyday tools in an ever-widening range of data-intensive industries, including agriculture, construction, surveillance, filming, healthcare, emergency medical services, energy, the environment, public safety, and security, points out the EC official. “In the future, drones could also be used as platforms for communication hubs, for weather and pollution monitoring, and for the maintenance of renewable energy installations, particularly offshore wind farms,” the EC official affirms. “In general, they offer a faster, more flexible and more economical and/or safer alternative to other modes of transport, such as helicopters. Further progress in the integration of drones into the airspace will require additional work on the Single European Sky rules to take into account the differences between the navigational performance of manned and unmanned aircraft.”

The key driver behind the progress so far in Europe has been industry expressing a clear and pressing business need and the European Commission putting in place a comprehensive and enabling policy framework in a timely manner, according to Boschen. “Added to that is the strong cooperation with the aforementioned standardization and certification bodies and the full inclusion of all stakeholders in the building of the U-space drone ecosystem,” he says. “In our area of research and innovation alone, we have succeeded in bringing on board all the relevant stakeholders, including cities and civic authorities, as well as emergency services and airports. This exposes lessons and experience not evident from sand-boxed research,” he says.

The true driver of industry change has been the ‘industry’ itself, namely the designers and manufacturers of new, primarily electric vertical takeoff and landing (eVTOL) aircraft, and traditional airlines who see an opportunity to expand their services to connect passengers door-to-door, explains Klooster. “The vehicles are here; several are almost certified and ready to fly while many more are in late design/early testing phases. The business cases are also solid, with many major market contenders working to advance progress,” he says.

As the drone services market continues to take shape in Europe, pressure is on to make sure that these air vehicles are safely and securely integrated into an already busy airspace, according to Garcia. “Transforming infrastructure and services to support such operations is critical to harnessing the potential of the sector, unlocking market growth, jobs and services for EU citizens,” he says. “However, a simple adaptation of the current air traffic management system is not enough; accommodating these air vehicles in the numbers forecasted requires a new approach. Citizens’ confidence and acceptance will be critical to the further development of the drone services market.”

The hope is that drone management and integration will ultimately allow for a large series of operations in harmony with the current ATM system.

Indeed, public perception of the UAV industry is mixed, points out Klooster. “As to the safety, cybersecurity and the environmental impact of UAVs, public opinion is beginning to shift as the number of use cases showing how UAVs can be used in critical scenarios is increasing, such as vaccine delivery to remote areas, rescue missions to save lives, and drone use in risky surveillance or remote inspection situation,” he says. “To increase awareness of UAV capabilities, in July 2022 Inmarsat announced a global partnership with Flight Crowd – a collaboration designed to improve engagement and understanding across the air mobility and aviation sectors, the public and the government. Through a series of collaborative outreach projects, we set out to showcase the wide-ranging benefits of this new industry, highlighting the capabilities of UAM and how it can support the mobility of people, goods and services while encouraging communities to have a say in the future of the flight industry themselves.”

According to Boschen, one obstacle is the terminology used to describe what is being done in the UAM/UAS domain. “Even now, stakeholders use terms differently, for example terms relating to altitude and height, separation, separation standards and minima, surveillance, tracking and so on,” he says. “Standardizing all these terms, and driving a common approach to performance requirements, will be essential going forward. This is something SESAR has placed a lot of emphasis on in the CONOPS. Before UAM can be contemplated, further work will also be needed on defining the flight rules, as well as certification and standardization for safe separation.”

One thing which is limiting progress in the industry is the delay in advancing current aviation regulations to accommodate the necessary changes to support the integration, observes Klooster. “Changing regulations is a very long and laborious process, primarily due to the fact that the existing airspace system is complicated, and not because there is a lack of desire for collaboration in the industry. Industry and regulators must work together to safely allow for the integration of a huge number of new aircraft types with varying capabilities, flight characteristics and operational purposes, while continuing to ensure the airspace remains accessible and efficient for existing users who are flying today,” he says. “In addition, key players must ensure that rules are aligned internationally so that new UAM operators do not have to adopt different equipment or procedures in each country they intend to operate in.”

Indeed, the integration of drones remains a complex issue and there are still areas to be addressed to ensure the effective implementation of U-Space in Europe, affirms Garcia. “This includes clarity on the responsibilities of actors within the system and how to facilitate interoperability and the integration of operations. Practical aspects of implementation and the electronic transparency of all airspace users must also be addressed,” he says.

Specific Requirements

U-space requires a high level of digitalization and automation of functions in order to support more complex operations, such as assistance for conflict detection and automated detect and avoid functionalities, explains Boschen. “The aim is to achieve automated drone management and integration, allowing for a large series of operations, many of them even simultaneous, and all of this in harmonious coexistence with the current ATM system. These requirements are coming from the drone industry and the wider aviation ecosystem through use cases and are integrated into our programme for further research and operational testing through established channels, such as the European ATM Master Plan,” he affirms. “They are also being fed into regulatory and standardization processes on U-space and UAM, and there are regular changes on these needs in fora such as the European Network of U-space Demonstrators.”

BUBBLES is a project targeting the formulation and validation of a concept of separation management for UAS in the U-space. SESAR image.

Drone technologies and use cases are evolving rapidly, with new products coming to market at an increasing pace that also cover a wide range of operations, from very low to high risk, the EC official highlights. “This is why the EU, in consultation with industry, has adopted a risk-based, operation-centric regulatory framework, which is regularly reviewed and improved to keep pace with this innovative sector,” the EC official says. “As this framework is performance-based, it is necessary to encourage faster development of technical and safety standards by all stakeholders to ensure that the pace of innovation in the drone industry can be maintained.”

In addition to the design and certification requirements for vehicles and operators, UAM operators will need supporting infrastructure within urban areas, according to Klooster. “This includes vertiports or multimodal transportation hubs, refuelling and recharging capabilities, a command, control and communications link to their vehicles, and a clear, agreed set of operating rules understood by all users of the airspace,” he says. “Requirements are currently being devised by aviation standards development organizations and government agencies, and also discussed across a variety of industry forums and local planning and community outreach efforts.”

According to Garcia, in order to attract the right talent in the future, it is necessary to revolutionize training capabilities, reduce certification timelines and invest in change management processes. “All stakeholders need to jointly work to create a global traffic management integration roadmap, including a pathway to AAM to plot a course toward full convergence of ATM and unmanned aircraft systems traffic management (UTM), and establish a network/ecosystem of aviation modelling and simulation tools and sandboxes to test, trial and demonstrate new forms of service provision,” he says.

Artificial Intelligence

Looking to the future, artificial intelligence (AI) has huge potential for supporting the integration of UAM and UAS, Boschen points out. “Given the forecast number of vehicles and operations, there is a real need to automate aspects of managing the airspace and the traffic. BUBBLES, a recently completed SESAR project, developed a concept of operations for separation management where applicable separation minima are dynamically updated using AI-based algorithms to adapt them to the actual performance of communication, navigation and surveillance (CNS) systems,” he says.

Another project, USEPE, investigated the use of machine learning (ML) algorithms serving multiple purposes, for example to help identify in advance conflicts using a recurrent neural network (RNN) algorithm, explains Boschen. “The developed ML engine provides an automated quantitative assessment of separation management. However, the use of AI is a relatively new domain for air traffic management and therefore more work will be needed on the trust framework and certification of these advanced decision-making tools,” he says.

The expansion of UAS operations will require the automation of a number of functions related to flight and traffic management, observes the EC official. “These areas are likely to benefit from the application of AI and ML technologies, which use data to train algorithms to improve their performance. This is still a dynamic area of research, but one for which the European Union Aviation Safety Agency (EASA) is already studying and developing guidance,” says the EC official.

The integration of flying taxis in a safe manner into the airspace system with a combination of autonomous and crewed operations raises considerations such as air traffic controller workload, communication delays, emergency management, voice-to-text technology, mixed equipage operation, and uncooperative aircraft, according to Garcia. “Legacy air traffic management systems were not designed for the automated aircraft of tomorrow. In the future UAM environment human intervention and coordination will be the exception, not the norm,” he affirms. “Automation will support a high level of safety, security, capacity, and scalability, while extending the capabilities of people. Establishing new, desirable, and legitimate roles for personnel that complements an automated, intelligent, data-powered system is key to the evolution of the aviation sector and its talent.”

AI and ML will significantly impact drones and UTM integration in urban low-level airspace, leading to higher levels of automation and safe operation, according to Garcia. “AI will be developed and used by USSPs and UAS operators, but regulated to ensure a legal framework that balances safety and citizen rights,” he concludes.