The latest episode in a long, successful story: ASTERIX categories 063 and 253 updated

A graphical representation of code.

From Babel to a one-stop shop for manufacturers and users.

In the past, different manufacturers encoded radar data in different languages, making it complicated for air traffic control centres to exchange them. To solve this problem, EUROCONTROL developed a unique data exchange language: the ‘all-purpose structured EUROCONTROL surveillance information exchange’ (ASTERIX) for both civil and military applications. It was just one language to run them all.

To keep this standard language current, we regularly update the categories (CATs for shot) – these are the documents describing the low-level implementation of a data format.

EUROCONTROL’s experts have just released new editions.

Category 063 (ed. 1.5) on Sensor Status Reports, clarifies that data item I063/070 has to be encoded in two’s complement, which is a way to encode negative numbers in binary format.

Category 253 (ed. 10) on Remote Monitoring and Control Information defines new source application identifiers in data item I253/030, adds data items (I253/120 and I253/130) for the transmission of extended transparent application data and allows the possibility of adding a reserved expansion field.

A global standard for a global community

ASTERIX is a globally accepted standard which establishes a common reference/rule for the transmission of air traffic services (ATS) information. It is also a state-of-the-art surveillance data format which has been adopted by a large diversified community of users from all over the world.


  • compact as it is designed for communication media with limited bandwidth. It follows rules that enable to transmit all the information needed, with the smallest data load possible;
  • versatile as it allows to encode any type of data;
  • open as its definition and specifications are free;
  • community driven as supported by a dedicated community of users who get a “plug and play” solution. They do not need to develop their own interfaces and the application of ASTERIX ensures interoperability between systems and users.

More about ASTERIX

For more on our innovative solution and it's library of categories.

Why we need new standards in ATM

ATM is evolving towards a more open architecture as well as new certification and regulatory frameworks, but any modernisation must go hand in hand with the evolution of standards and the ways we develop them.

Standards are essential for deployment, interoperability, harmonisation and enhanced operational efficiency. They also lower the costs of procurement and demonstrating regulatory compliance.

EUROCONTROL’s wide range of specifications and guidelines have played a central role over the years.

Specifications such as All-Purpose Structured EUROCONTROL Surveillance Information Exchange (ASTERIX), but also On-Line Data Interchange (OLDI), lie at the core of the current ATM system, following decades of progressive technical and operational developments.

Enabling a Single European Digital Sky

EUROCONTROL intends to be at the forefront of the evolution in standards while continuing to play a key role in providing them, notably for network operations, operational improvements and deployment. All this will help facilitate the digital transformation of the European Single Sky.

EUROCONTROL and standardisation

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