Fast-track U3 U-space advanced services and CNS capabilities

Expected Outcome

To significantly advance the following development actions:

• IR-6-01 U3 U-space advanced services addressing aspects such as common altitude reference, collaborative interface with ATC, tactical conflict detection and resolution, fairness in strategic deconfliction, etc.

Scope

The following list of R&I needs is proposed as an illustration of the potential project content, but it is not meant as prescriptive. Proposals may include other research elements beyond the proposed research elements below if they are justified by their contribution to achieve the expected outcomes of the topic and are fully aligned with the development priorities defined in the European ATM Master Plan.

• Collaborative interface with ATC: dynamic airspace reconfiguration (ATM/U-space)

Research shall further develop dynamic airspace reconfiguration (DAR) concept to facilitate that UAS traffic can access ATC controlled areas, ensuring the safe separation of UAS and crewed operations. Research objective is to develop a highly dynamic, responsive, and granular delegation of portions of controlled airspace in the ATM–U-space shared airspace (AUSA) to either ATC or U-space control, subject to ATM and U-space operational demands respectively. Research shall address the definition of ATM and UTM responsibilities and may address the impact on ATM and UTM capacity. AUSA is a region of controlled airspace where airspace delegation between ATM and U-space can occur.

The volumes in AUSA may extend from ground or a specified altitude and have a ceiling that may reach into any altitude of the controlled airspace. The horizontal shape and vertical boundaries of each volume can dynamically change before and during execution of an operation in AUSA. This can effectively create a “safe bubble” around the crewed aviation in those cases when most of the AUSA airspace is delegated to U-Space.

The research must consider the specific needs of military/state drones. Note that there is on-going work under project ENSURE.

• Operation of open and certified drones in controlled airspace without dynamic airspace reconfiguration (DAR)

This element aims at creating a concept for the operation of drones in controlled airspace that is not AUSA. It can also be used in AUSA as an alternative to DAR, e.g. to allow the operation of a single drone for which DAR is not practical. The first target use case is the operation of drones at controlled airports, e.g. for airport service activities (surveillance, delivery, NAVAID calibration). In this case, the drone will follow an ATC clearance. Communication between the drone pilot and ATC will be facilitated by a U-space service. The research must establish whether direct communication between the drone pilot is required. Acceptable clearances and minimum performance requirements for the drone may be required for this kind of operations, and the drone pilot may be required to undergo specific training (e.g. similarly to what is required for operating airport vehicles).

• Enhanced drone flight authorisation processes

As per the current regulation, to operate a flight in U-space airspace the operator must submit a drone flight plan to the U-space service provider (USSP), which the USSP must issue an authorisation for. For a flight plan to be accepted/authorised, it needs to comply with all known airspace constraints (e.g., geographical zones) and be strategically deconflicted from other drone flight plans. The objective of the research is to contribute to further develop the drone flight plan standard (including both data format, data exchange protocols and processes) beyond the existing (e.g., ASTM F-3548-21[1]) to include enhancements, such as:

• A two-step authorisation process, with first a drone flight plan acceptance to be followed by an authorisation to proceed (equivalent to a clearance for take-off) to be issued shortly before the flight moves to an activated status. Where the two-step process is not deemed necessary, the two authorisations will be issued simultaneously. The drone flight acceptance would be issued if the drone flight plan is complete and does not infringe any airspace restrictions, while the authorisation to proceed would be given after the applicable strategic deconfliction process has been completed. Both authorisations would have a time tolerance attached.
• The introduction of a limited authorisation option, where a flight plan is authorised to an (airborne) clearance limit rather than all the way to destination. Before proceeding beyond the clearance limit, the drone operator will need to receive an authorisation to proceed. This kind of authorisation is expected to be particularly useful for drones conducting successive inspection operations where the time the drone will need to spend over each of the inspection targets can’t be known in advance.
• Definition of non-first-in-first-out (non-FIFO) fair prioritisation rules in pre-departure strategic deconfliction, allowing the prioritisation of the flight authorisation for e.g. state or medical drones, or for ensuring a fair competitive environment for all drone operators. Note that a non-FIFO prioritisation rule that is not based on a FIFO principle[2] may require the revocation or amendment of an authorisation previously given to a lower priority flight to be able to authorise a higher priority flight.
• Inclusion of flight permission to fly in certain geozones as part of the digital U-space flight authorisation process.
• Update flight authorisation standard to include new elements from undergoing projects, such as vertiport selection and slot reservation.
• Interoperability between USSP and common information services (CIS).
• Standard to cover actual flight plan (not just interoperability between USSPs).

Research shall consider the dataset in the appendix of the regulation and may investigate the potential benefits of using additional data fields. The format of flight plan should be standardized and include all the required information (same info to be exchanged between USSPs, between USSP and user, between USSP and CIS), although research may conclude that some fields might not need to be exchanged between USSPs. Research shall address the time dimension of the authorisation process (e.g., when the authorisation process starts, when the process finishes, etc.).

To facilitate ATM-U-space interoperability the data formats should be as close as possible to the standards used for crewed aviation. The applicability of the SWIM standards for USSP-USSP-CISP data exchange should be investigated (e.g., publish/subscribe).

Note that CISP USSP interface is defined in EU IR 2021/664 and EU IR 2021/665 and their associated AMC/GM.

• U-space tactical separation management service for drones

Separation is defined as the tactical process of maintaining drones above the separation minima (between themselves or between a drone and a restricted access geozone). When it is foreseen that the distance will be below the separation minima (based on the information available from a trajectory prediction based on tracking and flight plan information), the tactical separation service will provide a modification of the trajectory to the drone or drones involved through the USSPs. When the trajectory of two or more drones needs to be modified, more than one USSP may need to be involved.

The primary objective of the separation service is to allow drones to receive flight authorisation for beyond visual line of sight (BVLOS) flight without the requirement that the planned trajectories be strategically deconflicted as currently required by the current U-space easy access rules in areas where the ground risk is such that the risk of collisions between drones needs to be mitigated. For areas with higher ground risk (e.g., over densely populated areas) a separation service may be the preferred option. It is expected that the implementation of the route modification proposed by the separation service will be mandatory for users having accepted a flight authorisation without prior strategic deconfliction (flight authorisation with tactical separation commitment). If time allows the drone operators or the USSPs may propose an alternative to the route modification proposed by the separation service. The research must define the process to define the separation minima, which may be dependent on the drone capabilities. The deconflictions (e.g., lateral deviation, vertical deviation, speed change, etc.) should consider the uncertainties in the current and future positions, for example relating to the altimetry system.

A tactical separation service may also make it possible for a USSP to grant authorisation for a drone to fly when there is uncertainty on whether it might find airspace restrictions along the route (e.g. if a restricted access geozone might become active). The separation between drones and crewed VFR aircraft entering U-space airspace is covered in the dedicated element “Separation between uncontrolled crewed VFR flights and drones”. The research may explore the synergies between these two separation services.

Research could also consider a combined strategic/tactical concept where some degree of pre-departure strategic deconfliction is still required, but there is a tactical separation service to cover the non-nominal situation where two or more drones are predicted to become closer than defined tactical and/or strategic separation minima, e.g. due to one or more drones having deviated from their flight authorisation beyond the allowed or expected buffers. In this context, the term tactical separation service refers to any modification to the authorisation of a drone flight that is already airborne, regardless of the time ahead from the current drone position where the new authorisation deviates from the original authorisation. When two or more drones are involved in the separation loss, a fair prioritisation framework may be defined to decide which drone (or drones) should be asked to change their trajectory (when time allows). Note it is expected that the buffers for the strategic deconfliction in a combined strategic/tactical concept could be lower than in the current strategic-separation-only concept.

Research shall consider scenarios including simultaneous operations of drones with different capabilities. The research output shall include operational concept and technical requirements including CNS requirements. Note that there is on-going work under projects SPATIO and U-AGREE.

• Enhanced ground risk assessment

The aim of the research is to provide automated support for the assessment of the ground risk of drone operations (the proposal should provide means to obtain the dynamic population density as per specific operations risk assessment (SORA) 2.5 plus subsequent versions, and also explore other risks and inputs useful to be included in enhanced guidelines to perform airspace risk assessment (ARA)). The basis for the ground risk assessment is expected to combine multiple information sources and be applicable both before the flight and during the conduct of the flight:

• Before the flight: platform for municipalities/authorities to evaluate the increase or decrease of the ground risks due to events (e.g., opening/closure of public spaces, festivals, sports events, etc.), consider historical mobile phone concentration and camera data, etc. At the same time, digital means to communicate this information to drone operators, both inside and outside U-space should be provided, updating (in the case of drone operations within U-space airspace) automatically the flight authorisations.
• In real time (during the flight execution): consider live camera and mobile phone data, platform for municipalities/authorities to report issues, etc. As in the previous case, digital means to communicate issues by municipalities and authorities should be provided, updating (in the case of drone operations within U-space airspace) automatically the flight authorisations in real time.
• Governance mechanisms to dynamically report and implement changes on UAS zones due to events or disruptions affecting the ground risks should be established and taken into account when defining digital means or platform to report this information to drone operators.
• Research shall take into consideration U-space lifecycle and coordination for U-space airspace establishment under Article 18.f of 664 Implementing Rule.

Research shall address the potential needs of a secured and trusted data base to support the elaboration the ground risk assessments.

Proposals shall elaborate a thorough state-of-the-art analysis on U-space ground risk management including relevant previous R&I work (both in and outside of SESAR).

Research shall take into consideration the work done under EASA on this element. Research may address the potential use of satellite data from the European Union Agency for the space programme (EUSPA) and from the statistical office of the European Union (EUROSTAT) regarding population data. Note that there is on-going work under project U-AGREE.

• Enhanced geofencing service

Geofencing allows U-space geographical zones with restricted access to be loaded into a drone pre-departure, potentially including mandatory update before each take-off, and may also include in-flight update. The concept includes the prevention of non-authorised flight at the level of the drone software. Geofencing is a useful mechanism to prevent accidental unauthorised entry into areas where drone flight is restricted, increasing safety levels (for example around airports and over sensitive areas over critical infrastructure or security-sensitive areas, etc.). The technology is mature and standardized (ED-269, ED-270 and ED-318), but there is a need to set up the framework to allow its widespread adoption. The gaps include database management framework, legal and liability issues, U-space services to process users’ authorisation to fly inside a restricted zone and specific processes to allow full access to state drones (e.g., police drones, border control, etc.). Note that geofencing is an option in the current regulation within the geo-awareness service.

Proposals shall elaborate a thorough state-of-the-art analysis on geofencing including relevant previous R&I work (both in (e.g., project Geosafe) and outside of SESAR), and not limited to European context. Research shall consider the recommendations included in the EASA report “study and recommendations regarding unmanned aircraft system geo-limitations”[3].

Research shall include a study of documented drone incidents that might have been prevented with a geofencing system to support the safety case.

Geofencing is a dual-use civil-military concept and technology. The project should consider the specific geofencing needs from the military community.

• Low-ground-risk DAA-based drone operations in drone only geozones

The objective of these research is to develop and validate a concept for the operation for small drones to operate over areas where there is no crewed aviation and with low-ground-risk without a requirement for pre-departure strategic deconfliction, where collisions between drones are prevented by the on-board DAA systems. When two drones are in conflict, the two DAA systems could coordinate with each other, for example based on a wifi connection as considered by previous SESAR project PERCEVITE. The concept must include a process for flight authorisation without strategic deconfliction of the planned 4D volumes, which could consider a DCB process to ensure a maximum density of operations as part of the criteria for approval. The capacity of airspace should be dynamically defined, e.g. there would be a default capacity, but it could be reduced in case of an increase in the ground risk (e.g., seasonally or due to an event) or the air risk, or under certain meteorological conditions.

Air-risk must also be mitigated. It is envisioned that the operation would be restricted to very low level (VLL). An altitude buffer below the upper level of VLL (500 ft) should be defined and validated. The size of the buffer could depend on the altimetry used by the drone (e.g., barometric, geometric GNSS, geometric real time kinematic (RTK), etc.) and on the capability of the drone DAA system to detect and avoid crewed aircraft. Both cooperative and non-cooperative crewed aircraft flying above VLL must be considered.

It is envisioned that the concept could be applied only in geographical areas where there is no crewed aviation. Even in this case, the safety case must address the contingency of a crewed aircraft entering the drone-only due to a flight emergency (e.g., via DAA). Planned crewed flights e.g. for a helicopter flight landing or military aircraft doing low level training should also be addressed (e.g., by DAA in combination with the provision of real-time information on the crewed flight plan to the drone operators via the USSP). Flight authorisation could be given for a limited time (e.g., 15 min) and be confirmed every 15 min. Proposals shall include an airspace risk assessment.

If the research is successful, a regulatory evolution should be proposed (e.g., for a new type of U-space airspace with different flight authorisation rules for these DAA-based operation areas).

• Altimetry for drones in very low level (VLL)

The objective of this research element is to provide altimetry solutions for drones. Both barometric and geometric altimetry solution should be considered. The research must study the comparative benefits of barometric vs. geometric altimetry for drones and investigate the operational impact of having drones with barometric and geometric altimeters flying in the same airspace volume (e.g. buffers in the separation minima to account for the different reference systems), and the comparability with QNH-corrected altimeter readings from certified aircraft.

• Barometric: when below the transition layer, barometric altimeters in (crewed or uncrewed) certified aircraft correct based on the local pressure at the airport or region via the use of the QNH setting. All aircraft flying in an airspace volume use the same QNH setting, which makes it possible to compare their altitudes and apply vertical separation between them. In contrast, small drones that use barometric altimeters use the pressure differential with respect to the take-off “home point”. If the elevation of the home point is known (e.g., from GNSS or from a chart), a QNH-like setting can be generated and used to correct the barometric altitude, hence providing a reasonably accurate altitude above MSL. However, drones taking off from different home points could have different QNH-like correction settings, which might make their altitudes not comparable in the general case (although the difference between the settings for drones taking off from sufficiently proximate home points might be negligible). The use of a regional-type QNH-like altimeter correction setting for drones could be used to ensure a common reference but would result in drones potentially having a non-zero altitude reading at the home point. The research should investigate the different options to make barometric altitudes from drones with different home points comparable, e.g. correction based on known elevation of home point for proximate home points (proximity parameter to be defined), use of regional correction settings for all drones in a specific volume, etc. The research should also investigate the comparability of altitudes between drones using barometric altimetry with some type of home-point or regional correction and QNH-corrected barometric altitude from certified aircraft.
• Geometric: geometric altimetry for drones is GNSS based and can use different means e.g., EGNOS, GBAS, real time kinematic (RTK) augmentation etc. to increase its precision. The research on geometric altimetry shall consider the research performed by SESAR project ICARUS. The research must characterise (providing a quantification) the comparability between geometric altimetry of drones with/without augmentation and aircraft flying with a QNH, focusing on the VLL airspace (500 ft or below).

The following additional altimetry-related areas of research are also in scope:

• Altimetry in the network identification and tracking reports from drones: drones provide altitude information through the tracking and remote identification services. For each of the altimetry methods considered in the research, the project should assess potential impact of using the method for reporting altitude in the network identification and tracking transmissions.
• Digital surface model (DSM) and digital terrain model (DTM) database management, including business aspects and service provision.
• Augmentation systems for increasing the precision of vertical altimetry in urban environments (e.g., EGNOS, GBAS, multi-drone cooperative, navigation using anchor vehicles, etc.).

The research should avoid proposing solutions enforcing additional requirements to other airspace users (in particular general aviation) and should be easy to understand for non-aviators (considering drone pilots in the open and specific categories). Applications to support the situational awareness of drone pilots in terms of altimetry are in scope.

Note that in this call WA 5-3 there is an element addressing altimetry for certified aircraft. While it may not be required that open and specific category drones and certified aircraft use the same altimetry system, projects working in altimetry for drones and projects working in altimetry for certified aircraft should share information and consider interoperability at low altitude or applicable buffers for separation.

• Separation between uncontrolled crewed VFR flights and drones

According to the standardised European rules of the air (SERA), except for take-off and landing, crewed aircraft must maintain an altitude of 1000 ft. or above the highest obstacle within a radius of 600 m when flying over cities, towns or settlements or over an open-air assembly of persons, and 500 ft. or above elsewhere. The U-space regulation allows BVLOS flights in U-space airspace subject to flight authorisation and specific operations risk assessment (SORA). U-space airspace is typically expected to be designated to cover up to 500 ft, but a higher boundary is also possible. The objective of the research is to investigate a concept to mitigate the risk of collision between crewed VFR aircraft and drones, examining different use cases:

• When the VFR aircraft is taking off or landing in U-space airspace. In this case, the U-space regulation requires that the VFR aircraft is e-conspicuous, and hence the USSP will have real-time position information. The concept should assess conflict management between drones a crewed VFR aircraft for which only the e-conspicuity information and evaluate the potential benefits of making additional information available to the USSP (e.g., the flight plan (allowing the USSP to anticipate that a VFR aircraft will take off or land), information from a flight information service (FIS) service if available, etc.).
• When the VFR aircraft is entering very low level (VLL) due to an emergency, and it is e conspicuous.
• Military low-level training operations.
• When the VFR aircraft is entering VLL due to an emergency. It is not e-conspicuous (as the entrance in VLL was unplanned, the VFR aircraft may not be equipped, or the equipment might not be switched on). In this case, the drone might use to detect the crewed aircraft. The research could investigate mitigation options for this case, e.g. use of electro-optical or sound detection equipment and DAA by drones flying below areas of intense VFR traffic and/or requirement for e-conspicuity for crewed VFR aircraft flying directly above U-space airspace.
• On the top boundary of U-space airspace: this is the case when the VFR aircraft is flying close to the ceiling of U-space airspace (typically VLL ceiling will be 500 ft, but it could be higher if the state has declared a U-space airspace with a higher ceiling) and the drone if flying just below the U-space airspace ceiling. In this case, the mitigation may include determining a maximum altitude drones should receive authorisation to fly at (e.g., 400 ft. for a U-space airspace ceiling at 500 ft) so that they stay always at a safe distance below crewed aircraft).

Research shall consider use cases including sports aviation (e.g., gliders, paragliders, ultralights, balloons, etc.), which usually do not need to file a flight plan.

The research must consider the altimetry systems used by drones and by crewed aircraft and investigate if an additional buffer is needed.

• Multidimensional optimised U-space flight planning and authorisation processes

Work is required to ensure that the new operations enabled by U-space are acceptable to the public. Specific areas of concern will be innovative air mobility (IAM) noise, visual pollution, privacy, urban and rural development, protection of natural environments, employment generation, etc. The introduction and growth of IAM must be carefully assessed and managed to ensure equity and sustainable improvement with regards to quality of life.

Research shall address the definition of a cost function for each mission including factors proven to have an impact (e.g., societal acceptance/visual pollution, noise, CO2 emissions, meteo, energy consumption, etc.) to be considered already in the flight planning process. This could give incentives to U-space operators to choose an optimised mission considering all relevant dimensions.

In addition, a consensus must be reached on the acceptable target level of safety of the different types of operations under U-space. The traditional definition for target level of safety may not be enough to encompass the context of U-space 2.0 and IAM operations (e.g., restricted geo-zones breach is not an accident, nor it would necessarily cause harmful effects to people but still considered unacceptable). Both real and perceived levels of safety should be considered. Responsibility, accountability, and liability are further fundamental societal concerns that must be considered. Allowing citizens to be involved in the overall development of the system is crucial to ensuring their consideration. General and leisure aviation needs should also be considered, especially when they are not subject to ATC.

• Counter-UAS (C-UAS) systems’ services for airport operations

The presence of drones in and around an airport can significantly affect flight operations and pose risks to the surrounding area. To ensure the safety of the airport, it is essential to detect and report drones, and appropriate measures should be implemented to address potential accidents or incidents.

There is a need to define the specification of the C-UAS system components (detection, tracking, identification and counter measures):

• Come up with an operational process integrating the interoperability with other systems, actions and procedures.
• Better identify the neutralization component – not the mitigation countermeasure.
• Assessment of impact level to manage the air traffic.
• Identification of threat and different types of threat.
• Need to identify protocols, roles (of aviation security, airport operator, national authority, air navigation service provider, human operator, pilots (crewed and uncrewed aircraft), UTM service provider, law enforcement authorities, intelligence agencies and other national security entities, military, local authorities) and responsibilities.
• Response procedures using C-UAS technologies and Human machine interface (HMI).
• Recovery of airport operations.
• Reporting investigation and trend analysis.
• Data retention.

Research also addresses the development of drone intrusion management service to support and mitigate contingency and restoration actions in case of drone intrusions in the airport environment (or against other civil assets e.g., nuclear plants, sensitive data centres, etc.). The proposed solutions will increase situational awareness and eases the coordination and decision-making process between the key actors that have an active role in the actual management of the drone incursion or drone incident management cell (DIMC) as defined by EASA. Research shall consider the output of previous ASPRID project.

• U-space advanced data exchange and communication service.

The primary objective is to investigate existing data requirements and develop innovative solutions to support a harmonised and interoperable U-space data exchange and communication service. The research shall cover the identification of necessary data and information to ensure the interoperability of current U-space services, as well as, the design of guidelines, communication protocols and data management strategies required to enable the full deployment of harmonised/interoperable U-space services.

The following key areas should be addressed:

• Data exchange mechanisms: validate data exchange protocols for real-time communication between operators, U-space service providers, CISP and traditional air traffic management (ATM) systems. Explore data exchange models to enhance scalability and robustness.
• Interoperability and standardization: identify existing data format standards, protocols and processes that can support interoperability between different U-space service providers and between U-space and traditional ATM systems.
• Standardization framework: consider datasets in the appendix of the regulation, propose updates or new data fields, standards, and protocols to ensure seamless interoperability and facilitate global adoption of U-space services. Identify risks and propose guidelines / methodologies to avoid misalignment and ensure full compatibility for data exchange.
• Automated data management: design automated systems for appropriate data collection, processing, storage, and dissemination to support real-time decision-making and situational awareness (per user type (e.g., USSP, CISP, drone operator, vertiport operators etc.)).
• Cybersecurity: Endpoints, data connection and ecosystem are cybersecure thanks to enhancement to key properties of information security such as, but not limited to, strong identification, authentication and integrity. Research shall consider the on-going work by ICAO on the international aviation trust framework (IATF), which aims at developing standards and harmonised procedures for a digitally seamless sky and dependable information exchange between all parties.

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• Infrastructure monitoring services

Research addresses the development of infrastructure monitoring services, including:

• Navigation infrastructure monitoring service: the service is expected to provide up to date status information about navigation infrastructure. This service is intended to be used before and during operations. The service should give warnings of loss of navigation accuracy. Specifically, the GNSS service retrieves data from the EGNOS data access service (EDAS), from the Reference Stations database and, through the USSP API, from the U-Space Tracking and Monitoring service provided by the USSP. Once all the necessary data have been obtained, the service can provide GNSS signal monitoring, position velocity and time (PVT) and Integrity calculation. This service may also distribute correction information coming from augmentation services, and even real time kinematic (RTK) augmentation as appropriate.
• Communication infrastructure monitoring service: the service is expected to provide up to date status information about communication infrastructure. This service is intended to be used before and during operations. The service should give warnings of degradation of communications infrastructure.

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• Mitigation of noise impacts of open and specific category drones

This element covers the development of a framework to assess the noise annoyance caused by small drones and propose and validate mitigation strategies, with a focus on mitigation strategies that may be applicable in the short term, e.g. establishing minimum flying altitudes or maximum speeds.

[1] Standard Specification For UAS Traffic Management (UTM) UAS Service Supplier (USS) Interoperability.

[2] FIFO schemes include, e.g. the first-filed-first-served scheme, whereby flight authorisation requests are processed sequentially in the order they are received, i.e. a flight will not be authorised until all the flights that have previously requested an authorisation have been authorised. An alternative FIFO approach could be that requests could be processed in batches according to milestones, e.g. XX minutes before a take-off-time-interval, with authorisations being processed sequentially based on the planned take-off time.

[3] Study and Recommendations regarding Unmanned Aircraft System Geo-Limitations | EASA (europa.eu).