ADS-L as the technological basis for visibility
ADS-L (Automatic Dependent Surveillance - Light) is a system that transmits the position and identity of an aircraft by radio without the need for expensive certified ADS-B hardware or frequency bands requiring a licence. In contrast to conventional transponders, ADS-L relies on more cost-effective sensor technology and therefore contributes to electronic visibility, particularly in low airspace.
The ADS-L 4 SRD860 specification enables the use of unlicensed 860 MHz frequency ranges to make aircraft visible at close range. This technology is particularly relevant in the context of European U-Space, i.e. the controlled airspace that will enable drones, manned aviation and automated services to co-exist safely in the future.
Significance for U-Space and BVLOS operations
With the development of U-Space - an airspace supported by digital services - comes the need to be able to recognise and track all airspace users electronically. ADS-L is designed to make manned aircraft visible when entering these zones, thereby avoiding conflicts with drones. At the same time, drone operators benefit from a better situational awareness and greater acceptance in line with safety requirements, especially when flying beyond visual line of sight (BVLOS).
The new specification contributes to a consistent picture of air traffic by strengthening interoperability between manned and unmanned aviation. This not only benefits safety, but also creates the basis for automated traffic flows that are expected in urban or industrial environments in the future.
New content in edition 2
Edition 2 of ADS-L 4 SRD860 now available includes a number of relevant enhancements based on both technical experience and industry feedback:
Refined transmission requirements
Following initial implementations, transmission parameters were specified more precisely, data quality was improved and the behaviour in the frequency band was further specified. The aim is to increase reliability while minimising system complexity.
Extended ground-to-air forwarding
A newly integrated mechanism enables the transmission of air traffic data and hazard reports from the ground to the air. This allows pilots to be informed in good time about traffic situations, airspace structures or meteorological risks. This concept is similar to ground-based services commonly used in the transponder environment, but in a simplified form.
Preparation for unmanned aerial vehicles
The link with existing standards for the remote identification of drones makes it clear that ADS-L will also be used in the unmanned sector in the long term. This will result in a harmonised approach to visibility requirements across different aircraft classes.
Improved interoperability and future viability
In future, ADS-L devices will be able to transmit their own capabilities, creating a kind of „self-description“ of the system. This facilitates integration into networks, scaling to more participants and future system expansions.
Interaction between regulation and industry
The new specification was developed in close consultation between regulatory authorities, manufacturers of avionics and drone systems, operator associations and user groups. This cooperative approach is intended to ensure that the specification remains practicable and meets the needs of a heterogeneous range of users - from gliders to professional drones.
A coordinated approach is crucial, as aviation is currently undergoing a transformation process: alongside traditional manned aviation, drone services, air taxis, automated supply chains and new classes of aircraft are establishing themselves in urban airspace. Technologies such as ADS-L provide the basis for sharing access instead of restricting it.
Outlook and opportunities for participation
EASA invites manufacturers, operators and associations to participate in the ADS-L Coalition. The aim of this forum is to support implementation, stimulate innovation and ensure that systems, regulations and real operating environments remain harmonised.
Europe is thus taking a cooperative approach to making electronic visibility the norm. This is also relevant because safety in lower airspace is increasingly being organised digitally and based on data. Visibility and situational awareness will become key pillars if manned and unmanned aviation share the same airspace in the future.
Conclusion
With the publication of the new ADS-L 4 SRD860 specification, European aviation is setting another milestone on the way to greater safety, efficiency and coordination in airspace. The technology enables cost-effective electronic visibility, facilitates access to U-space and creates a harmonised basis for the integration of new air traffic participants. The further developments of Issue 2 also show that Europe not only wants to regulate aviation, but also actively develop it further - with the aim of creating a networked and sustainable air transport system.
Source references:
Flieger.News
