1.1 Introduction

With the passing of time, electronic technology has come to play an increasingly important role in military operations. The electronic era, and with it the first steps in the introduction of electronics.into weapons, goes back to the time when radio and the radio direction finder were first used to give the platform position. The second step was the introduction of radar for the detection, and location in angle and in range, of hostile platforms, and its subsequent use to increase the accuracy of artillery. The last step, and probably the most lethal one, has been the use of electronic devices for precision guidance of missiles (Figure 1.1).

Figure 1.1: A missile system exploits radar signals to hit its targets with precision.

The effectiveness of electronically guided weapon systems, expressed in terms of kill probability, has risen to values very close to unity, thus leaving undefended targets little hope of escape. Consequently, almost all effective weapons now employ electronic guidance devices. However, the sophistication of today's weapon systems is such that they are rendered worthless should their electronic circuits not operate correctly. As a result, it has become essential to develop counter electronic systems capable of reducing the effectiveness of weapon guidance devices.

The fruitfulness of these countermeasure techniques has quickly become apparent. They have been developed to the point that they can seriously degrade the performance of nearly all weapon systems (Figure 1.2). The inevitable next step has been the development of counter-countermeasures to try to restore the...