ATSEP maintain for their Air Navigation Services Provider (ANSP)
- Communication,
- Navigation,
- Surveillance and
- AirTraffic Management (ATM) systems/equipments.
However, other infrastructure is also often maintainded by them, such as Power Supplies or Meteo systems and sensors.
New technical challenges in the ATSEP domain are cyber security, virtual datacenters and Towers.
What IFATSEA concerned all these infrastructure are safety relevant, and several safety critical and should only maintained and certified by ATSEP who are trained and competent.
Reg 2017/373, in Article 6 Service providers, state that
(h) for providers of communication, navigation or surveillance services, in addition to the requirements of points (a), (b) and (c), the requirements laid down in Annex VIII (Part-CNS);
CNS.OR.100 Technical and operational competence and capability
(a) A communication, navigation or surveillance services provider shall ensure the availability, continuity, accuracy and integrity of their services.
(b) A communication, navigation or surveillance services provider shall confirm the quality level of the services they are providing, and shall demonstrate that their equipment is regularly maintained and, where required, calibrated.
https://www.easa.europa.eu/faq/45949
Nowadays DataProcesing is often used instead of ATM infrastructure, to avoid confusion with ATM services.