Passive Bistatic Radar and Waveform Diversity

This tutorial describes the basis of passive bistatic radar (PBR) systems, and in particular the nature of the waveforms of illuminators of opportunity that they exploit. It shows that there is a wide variety of such waveforms, from broadcast, communications and radionavigation transmissions, and that in general they are not optimum for radar purposes. In addition, they usually vary significantly as a function of time, with the imposed modulation. It is therefore necessary to understand the effect of the waveform on the performance of the passive bistatic radar, so as to be able to choose the most appropriate illuminator, and to use the waveform in the optimal way, and it is in this sense that PBR forms a part of the subject of waveform diversity. The tutorial presents a short summary of the properties of bistatic radar, then goes on to consider the specific case of passive bistatic radar. Next, two brief sections provide a review of the radar equation for bistatic radar and of the ambiguity function for bistatic radar, before considering the properties of a variety of different waveforms that may be used for passive bistatic radar purposes and how best to exploit them. Finally, a description is given of some practical passive bistatic radar systems and examples of results.