A core element of the system is the Sensor Data Fusion (SDF) server to present detector output to end-users. The basic structure of SDF has been designed with regards to the requirements of the ISMAEL system and a significant part of it has already been developed. The Sensor Data Fusion Server can be divided in five subsystems:
1) The Graphical User Interface;
2) The Data Processing Unit;
3) The Tracker of the system;
4) The ASTERIX encoder (for data interchange with other surveillance systems) and
5) The Data Transmission Unit.