The first SAW based IFF system and its operation in Austrian aerospace defence

Starting in 1976 for the Austrian air surveillance (SSR) system, required by the neutrality status of Austria, an identification friend or foe system (IFF) was designed, simulated and realized at the Vienna university of technology in about 20 diploma and PHD theses in cooperation with the Austrian ministry of defense and Schrack inc., Vienna. Goal was to make it resistant against deceptive electronic counter measures (ECM). Using surface acoustic wave (SAW) chirp filters identification signals with high time bandwidth product were achieved. The IFF was flight tested in 1988 and came to successful use in the Yugoslavian civil war 1991, when Austrian airspace neutrality was violated by MIG fighter planes, equipped with ECM.