The ANTENNAE project aims to adapt 3GPP telecommunications standards for communication, navigation, and surveillance (CNS) services to support safe and efficient low-altitude aircraft operations.
The ANTENNAE project explores the applicability of 3GPP telecommunications standards for delivering the full range of communication, navigation, and surveillance services to all classes of aircraft operating at low altitude while supporting key Air Traffic Management (ATM) and U-space stakeholders. The ANTENNAE solution looks at the use of 5G and next-generation (6G and beyond) cellular networks through a hybrid connectivity framework that integrates terrestrial (TN) and non-terrestrial (NTN) systems. The integrated CNS concept leverages efficient spectrum use to offer greater service resilience, improved connection capacity, and the service continuity needed for cost-efficient, safe aviation operations at low altitude.
From take-off to landing: The critical role of CNS in aviation
Communication, navigation, and surveillance is the cardiovascular system of airspace management, enabling safe aviation operations in crowded airspace where thousands of aircraft are flying. CNS was originally designed for legacy high-altitude aircraft, with three fragmented and poorly integrated domains: ‘C’, ‘N’, and ‘S’. These three domains complement each other and underpin safe aviation operations by providing air navigation services. In the current CNS ecosystem, each domain operates independently, using distinct technologies, hardware, and frequency bands.
- Communication plays a crucial role in facilitating data exchange between aircraft-to-aircraft, aircraft-to-ground, and ground-to-ground. For example, Controller Pilot Data Link Communications (CPDLC) and Aircraft Communication Addressing and Reporting System (ACARS) are widely adopted aviation communication protocols that have been in use for several decades in manned aircraft.
- Navigation is essential for flight planning and ensuring that aircraft fly safely from one location to another within the correct air corridor in controlled airspace in accordance with international standards. Navigation services are key enablers for geofencing solutions to prevent aircraft from entering restricted areas. The Global Navigation Satellite System (GNSS) is the most widely adopted system for aircraft navigation. Beacon-based navigation solutions, including Distance Measuring Equipment (DME), Very High-frequency Omnidirectional Range (VOR), Instrument Landing System (ILS), and Non-directional Beacon (NDB), are other well-known technologies to support manned aircraft navigation during different flight phases.
- Surveillance enables situational awareness by detecting, tracking, and identifying aircraft. It makes sure only authorised aircraft are within its designated areas. In manned aviation, traditional surveillance systems include the Airborne Collision Avoidance System (ACAS), Automatic Dependent Surveillance-Broadcast (ADS-B), Primary Surveillance Radar (PSR), and Secondary Surveillance Radar (SSR).
All three domains, ‘C’, ‘N’, and ‘S’, are equally important and essential for any stage of any flight and therefore are heavily integrated into the aircraft systems, making them the backbone of aviation.
The limits of legacy CNS in a changing airspace
Emerging U-space operations within the Innovative/Advanced Air Mobility concept are creating new challenges for the airspace by enabling a new generation of small, highly manoeuvrable, and highly automated aircraft to operate at low altitudes alongside legacy aviation users. Traditional CNS systems and their key technologies were designed for high-altitude aircraft and provide limited coverage at lower altitudes, where the next-generation aerial vehicles, including Unmanned Aircraft Systems (UAS) and Vertical Take-off and Landing (VTOL) Capable Aircraft (VCA), will fly for aerial work, logistics, human transportation, and public services. The legacy CNS technologies face challenges to meet the requirements of next-generation aircraft and U-space operations. The key challenges are as follows:
- The current CNS system, originally designed for high-altitude aircraft and ATM, provides limited coverage at very low-level altitude and metropolitan areas for U-space operations.
- Each service ‘C’, ‘N’, and ‘S’ uses a separate device or several devices, technology, and frequency spectrum, resulting in high development and operational costs.
- Due to safety and operational complexity reasons, it is challenging for small unmanned aircraft to carry multiple radio devices and batteries to power and use a fragmented CNS system.
For UAS and VCA operations to share the airspace with legacy aviation, the coordination and deconfliction require new CNS infrastructure to ensure airspace safety.
Rethinking CNS: From fragmentation to integration
The growing UAS and VCA users at low altitude calls for an innovative, sustainable, and cost-effective CNS solution. Integrated CNS (ICNS) concept delivers the ‘C’, ‘N’, and ‘S’ services through the same technology stack. This means that ICNS will eliminate the need for multiple onboard hardware devices, reducing the number of required network devices and the aircraft’s battery payload. ICNS considers the C, N, and S domains as a harmonised framework. This new concept allows one domain to support and complement another domain. Given this, all systems for C, N, and S services might be combined and harmonised into a single system. ICNS also helps minimise the carbon footprint of wireless systems.
Bridging today and tomorrow: ANTENNAE’s path to integrated CNS
The ANTENNAE project investigates the applicability of 3GPP telecommunications standards for delivering ICNS services at low altitude to support both piloted and U-space operations. To achieve this goal, the ANTENNAE project considers integrated terrestrial and non-terrestrial networks to deliver continuous coverage and a full range of CNS services to low-altitude operating aircraft, while supporting key aviation stakeholders.
The role of ground networks will be to provide the primary connection in areas with well-developed infrastructure. Satellite networks, in turn, will support CNS operations in regions beyond the ground network coverage, such as oceanic and rural areas. Commercial cellular networks are optimised for ground users, with down-tilted antennas serving streets and buildings, and therefore do not adequately support aerial users. Satellite systems can provide coverage at altitudes above the effective range of terrestrial networks. Additionally, satellites can help offload CNS traffic from the ground network, reducing congestion during peak hours and in high-air-traffic-density areas. In the event of an outage, these networks can act as a fallback for each other, strengthening resilience and improving connection availability and service continuity required for autonomous operations Beyond Visual Line of Sight (BVLOS).
By leveraging the benefits of 3GPP terrestrial and non-terrestrial networks, ANTENNAE introduces an ICNS framework that supports both high- and low-level altitude operations, optimises airspace capacity, and reduces fuel and battery consumption, thereby lowering carbon emissions. Thus, the ANTENNAE enhance safety and sustainability, meeting the current and future needs of ATM and U-space systems with improved capacity, performance, and latency compared to legacy CNS systems.
Disclaimer
This project received funding from SESAR 3 JU and the European Commission and operates under the Grant Agreement 101167288.
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