Together with the parallel report "Quantitative Decisions in a Network Centric Defence", FOI-R--1390, November 2004,by Lars Falk, the present report describes results obtained within the FOI-project "Electronic Warfare and Network Centric Defence" up to October 2004. Following the introduction of quantitatively defined concepts from (communication based) information theory, detection theory, general estimation theory, and also perception psychology, it is shown that these concepts lend themselves well to quantitative analysis of decision processes in a general air defence system where hitherto only intuitive judgements, and/or assumptions, formed the basis for critical decisions. An important result from Bayesian detection and estimation theory applied to general desicion making, is that all available prior knowledge must be used in order to reach decisions that are optimal.