Transition towards high performance of air-ground connectivity (multilink)

Topic updates

29 January 2026

18 September 2025

Call HORIZON-SESAR-2025-DES-IR-02 has closed on the 16-09-2025.

39 proposals have been submitted for a total EU grant requested of around 315 MEUR.

The breakdown per topic is: 

Evaluation results are expected to be communicated in February 2026.

15 July 2025

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Transition towards high performance of air-ground connectivity (multilink)

TOPIC ID: HORIZON-SESAR-2025-DES-IR-02-WA2-1

Type of grant: Call for proposals

General information

Programme: Horizon Europe (HORIZON)

Call: Digital European Sky Industrial Research 02 (HORIZON-SESAR-2025-DES-IR-02)

Type of action: HORIZON-JU-RIA HORIZON JU Research and Innovation Actions

Type of MGA: HORIZON Lump Sum Grant [HORIZON-AG-LS]

Status: Forthcoming

Deadline model: single-stage

Planned Opening Date: 01 April 2025

Deadline dates: 16 September 2025 17:00 (Brussels time)

Topic description

Expected Outcome:

To significantly advance the following development actions:

• IR-2-01: Complete development of successor(s) to VHF datalink mode 2 (VDL2): L-band digital aeronautical communications system (LDACS), hyper-connected ATM, and satellite communications covering civil-military dual use.
• IR-2-02: Aircraft as a sensor, including transmission of humidity information to ground, etc.

This includes advancing the capabilities of the following systems:

• Airborne systems: aircraft sensors.
• Air-ground systems: air-ground communication links.

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.

• Hyper Connected ATM

Research aims at completing the delivery of hyper-connectivity solutions that allow the use of non-safety-approved commercial public air-ground communication links and networks (e.g., 5G mobile networks, commercial Ku/Ka-band satellite communication, etc.) as a complement to legacy safety links, whilst meeting the required safety, security, and performance standards for safety-related air-ground communications. The proposed solution will leverage state of the art “at hand” commercial radio infrastructure already deployed to serve in-flight connectivity for passengers, use them ‘as they are,’ and aim at enhancing some end-to-end cockpit communications general performance (e.g., bandwidth, latency, etc.) in nominal conditions.

Research shall consider an interim precursor scenario integrating the hyper connected ATM concept into the existing environments (ACARS and ATN/OSI), but also a target scenario considering the full integration of the hyper connected concept within an ATN/IPS environment and the future communication infrastructure (FCI). To complete TRL6, research activities shall consider the execution of live flight trials involving test aircraft with on-board pre-industrial prototypes. These live flight trials can be performed in Europe and may be extended across continents for addressing global interoperability aspects.

Research shall address the alignment with European Space Agency (ESA) Iris programme research initiatives, which are addressing the use of Ka band satellite technologies for safety critical communication.

Note that work on this research element is on-going under project FCDI SESAR solution 0339 “Hyper Connected ATM Precursor” and SESAR solution 0340 "FCI Services - IPS Enhancements".

The hyperconnected ATM concept is based on the use of public networks for aviation safety-critical data traffic. As safety-critical data traffic increases, VDLM2 may not have the capability to back-up the whole safety-critical data traffic, which increases the need for multilink, including making use of non-aviation networks. Hyperconnected ATM is a set of mechanisms that allows making use of both safety and non-safety links (e.g., AOC data could go over non-safety critical links). Research shall consider situations in the safety and security cases such as avoid single point of failure for two different communication providers (that may have back-up contracts between them), or simultaneous failure of the services of all satellite communications due to atmospheric phenomena or cyber-attack, etc. Since hyperconnected ATM uses public networks, research shall consider advanced techniques and approaches to enhance cybersecurity to address new attack models/vectors that may stem from the new scenario. Also, research shall address potential conflicts with spectrum frequency allocation.

Research should also investigate applicability to HAO.

• Complete the development of digital voice CONOPS and technical capability

The research area addresses the development of the technical capability to exchange digital voice services. Digital voice is foreseen to replace VHF radio completely in the long term in all operational environments: continental (en-route (flight-centric or with geographic sectors, continental high and low density), TMA and tower (TWR), including ground and platform control) and oceanic. The proposed technical solutions should be configurable to support both party line and point-to-point ATS-pilot communication. The research’s initial step will consist of describing the applicable operational use-cases for digital voice (i.e., CONOPS).

The research area covers the development of the digital voice capability for L-band Digital Aeronautical Communications System (L-DACS), Satcom and hyper connected ATM solution. Besides interoperability, RF spectrum supportability needs to be addressed with military systems including military systems providing service to civil aircraft. To complete TRL6, research activities shall consider the execution of live flight trials involving test aircraft with on-board pre-industrial prototypes. These live flight trials can be performed in Europe and may be extended across continents for addressing global interoperability aspects. On L-DACS digital voice capability, research shall consider the work done under SESAR solution PJ.33-W3-02 “L-DACS digital voice capability”, which achieved TRL4 in SESAR 2020.

• Aircraft as a sensor

Research aims at improving flight safety and efficiency by enriching usual MET information sources with MET data from on-board sensors (e.g., icing, hail, turbulence, wind, humidity sensors and temperature) provided via data link services. The service could be then consumed by ground systems (e.g., trajectory predictors) in real time. This will also deliver environmental benefits by reducing CO₂ and non-CO₂ emissions (e.g., high precision humidity sensors/data are an essential ingredient for precision of contrails prediction models, and consequently for mitigation of contrails formation). Research areas may include very short-range weather forecasts based on aircraft meteorological data relay (AMDAR) and observational data assimilation (e.g., predicted wind, wind shear, etc.) during the approach and landing phases, Mode-S EHS, new possibilities emerging from ADS-C, etc., and their distribution to ground, additional enabling sensors for non-CO₂ emissions (e.g., lidars, etc.).

In addition to information from onboard sensors, pilots receive updates in various formats via datalink including simple text messages, graphical products, and satellite images. These inputs cover different timeframes, ranging from past observations to predictions for the next several hours. It falls to the pilot to organise and geo-reference these data, and temporarily build a mental picture as fast as possible. Research shall address innovative solutions to support intelligent data pre-processing, smart filtering, and integration and fusion, both on ground and on board the aircraft for the two-way exchange of data collected by the vehicle’s own sensors as well as satellite based and terrestrial navigation (e.g., exploiting multi-constellation double frequency GNSS), surveillance and weather systems. The research shall consider the novel avionics and flight crew procedures required to use this information. Downlink and uplink of weather parameters (pressure, temperature, wind speed and direction), turbulence, space weather, icing considerations and contrail related information (e.g., air humidity) shall be addressed.

The research will contribute to EUROCAE WG-76 and RTCA SC-206 MET datalink standardisation, and ICAO is also developing standards for turbulence and space weather which could be downlinked or uplinked via a SWIM purple profile service. Research shall consider the work done under solution PJ.14-W2-110 “Aircraft as an AIM/MET sensor and consumer”.

The research scope also covers the development of aircraft-centric sensing technologies able to detect obstacles on or near the runway or potential runway incursions during take-off and landing operations, including enhanced traffic surveillance technologies able to mitigate low ADS-B updates rates from aircraft on ground, or pilot aids for prediction of other-aircraft intent based on traffic movement monitoring and recognition of ATC voice and future datalink-based clearances.

Research may also include the transmission of the runway condition code (RWYCC) (partially delivered under SESAR2020 PJ.02), both for air and ground sub elements. Among the research elements, further works on air-ground synchronization is required (e.g., downlink and integration of on-board braking action computation system (OBACS) data).

This research may also cover the development of innovative LIDAR-based ATM applications.

• Pitot-static systems, which are traditionally used by flight avionics as air-data technology, present limitations related to failure modes, environmental sensitivity, etc. Research aims at developing LIDAR based solutions that, applying a different approach (based on optical means), meet or exceed the performance of traditional pitot-static systems, overcome the limitations mentioned above and support requirements for all weather and all flight phases.
• The available technologies/procedures that help the pilots recognising the presence and severity of icing conditions (e.g., weather forecast, operational procedures, etc.) are limited and they are not able to assess the severity of icing conditions. Research aims at developing LIDAR based sensors able to detect the particles present in the vicinity of the aircraft, identify their type (e.g., ice, volcanic ash, sand, dust, etc.), measure their size distribution and mass concentration in the air and quantify the severity of icing conditions.

These solutions aim at improving safety. In addition, downloading more accurate air data information from the aircraft will also improve weather models and non-CO₂ models resulting in efficiency and environmental benefits.

The development of the services to aggregate the data downlinked from the aircraft, its fusion with data from ground sensors (e.g., LIDAR, ground cameras, etc.) and the distribution of the associated improved predictions (e.g., climate MET services) and corresponding business models is also in scope.

Specific minimum requirements for this topic:

• Proposals addressing Hyper Connected ATM and digital voice capability must aim at completed delivery at TRL6, no deviation will be accepted.
• Civil-Military systems spectrum compatibility shall be addressed.

Start submission

The submission system is planned to be opened on the date stated on the topic header.

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