The TopSky (formerly EUROCAT)^[1] system is a computerised air traffic control and management solution^[buzzword] developed by Thales Air Systems (formerly Thomson CSF).^[2] It utilises a distributed computing architecture and is capable of integrating geographically dispersed air traffic control units within a Flight Information Region (e.g. control towers at different airports and en route control centres) into a single coherent system.

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During 2012, the Thales marketing name has been changed from Eurocat to TopSky.

TopSky handles a large variety of different functions required for the smooth operation of air traffic control and management. A non-exhaustive list includes:^[3]

• Surveillance data processing and track correlation (radar, ADS-B, ADS-C etc.)
• Flight plan processing
• Communication (CPDLC etc.)
• Aeronautical information data processing (NOTAMs, QNH, wind aloft etc.)
• Flow control and sequencing
• Human-machine interfacing (e.g. correlating data to generate controller's display)
• Data recording
• Controller situational awareness and alerts generation
  • Squawk Emergency (EMG), Radio Failure (RAD), Hijack (HIJ)
  • Short Term Conflict Alert (STCA), Minimum Safe Altitude Warning (MSAW), Danger Area Infringement Warning (DAIW) etc.
  • Non-Transgression Zone (NTZ) alert, DUPE Alerts, FPCF Alerts.

The software is used in many countries, including: