The present report comprises part of the scheduled reporting within the FOI project "EW in Network Centric Defence". One important purpose is to provide a technical and theoretical foundation for performed and coming simulations of electronic warfare attacks against radar- and SSR-based air defence systems. The report also provides an outline of the personnel´s perception and interpretation of an ongoing attack. The effect of possible deceptive measures on the decisions on the higher C2I levels is also discussed. This analysis is based on concepts from information and detection theory, and also perception psychology. These concepts were introduced and discussed in earlier reports by the same author within the above mentioned FOI project .