Development testing of the Mark XIIA Mode 5 next-generation identification friend-or-foe (IFF) system is under way, led by the US Navy. The system is intended to replace the ageing Mark XII IFF, and resolve long-standing performance limitations and concerns over security of the encryption algorithm used for the Mode 4 "question and answer" interrogation.
Mode 5 is a new digital waveform that provides secure co-operation identification of friendly platforms, and is designed to be inserted into the latest open-architecture IFF interrogators and transponders. The waveform includes a new communications-security algorithm that only transponder-equipped platforms can decode.
In use for 40 years, the Mark XII IFF has severe performance limitations including range, self-interference or garble, multipath fading and interference from civil air traffic control systems. Flight testing of Mode 5 has demonstrated enhanced security, multipath performance, anti-garble, reduced ATC interference and NATO interoperability, says the USN.
New features of Mode 5 include a random reply delay that minimises the probability that transponder replies from closely spaced targets will interfere with each other. Another is lethal interrogation, which the USN says allows the friendly platform to operate in stealthy emission-control mode.
The USN plans initial operational capability with Mark XIIA Mode 5 in 2007.
GRAHAM WARWICK/WASHINGTON DC
Source: Flight International
