When the International Civil Aviation Organisation mandated that all aircraft flying
in controlled air space must be fitted with ATC (mode S) capable transponders most of the worlds
military aircraft needed to be updated.
Older transponders are responsible for reporting an aircrafts identity and altitude when interrogated
from the ground. For military aircraft the transponder can
also reply to encrypted interrogations with a series of encrypted replies that allow a decision to
be made if the aicraft is a friend or foe (IFF). Mode S transponders are considerably more complex having data link, collision avoidance, GPS position reporting etc.
Raytheon(uk), a subsidiary of one of the worlds largest defence companies, had developed much of the
hardware for the European Fighter Aircraft transponder (which included the new modes) but the
software had been developed by another EFA partner.
Raytheon subcontracted the software development to Aonica as we allready had the experience
of developing components of the European Fighter Aircraft IFF Interrogator software.
The software was developed, documented and tested to DOD military standards and coded in Misra C.
The Raytheon IFF 4800 series transponders offer Modes 1,2,3A,C,4 and S and an integral Mode 4
cryptographic computer.
Other features include interfaces for a Mode S air data link processor,
collision avoidance system and GPS position reporting,
