Status signalling system

This project involved the hard- and software development for a NAVIGATION EQUIPEMENT STATUS SIGNALLING (NSS) system. This system provides status overviews of the navigational systems of Schiphol and Rotterdam airport. These status overviews are generated at a central location at Lucht Verkeers Leiding Nederland (LVNL) and sent to the tower of Schiphol airport and to the approach operator’s desks. One of the system requirements was that the system up-time would be more than 99.99%. Therefore a dual server configuration is developed that receives and monitors the statuses of the NAVAIDS through serial and parallel interfaces. These interfaces are connected in a redundant configuration. If one server or interface fails then the other server takes over without any loss of data. Since the light conditions in the tower are exceptional, special displays had to be developed that could fulfill the requirements needed in this situation. The system logs all status changes to magnetic tape for statistical investigation.


  • Dual server configuration with redundant I/O interfaces
  • Automatic switchover at malfunction
  • System up-time >99.99%
  • 24 connected display units in the tower and at the approach operator’s desks
  • Serial and parallel interfaces to several systems used at LVNL
  • High brightness tower display units