Guest editorial special issue on passive radar (Part I)

Passive radar (passive coherent location, PCL) has been monitored and discussed repeatedly over the last decade by the aerospace and electronic systems community. Within the last few years system concepts, experimental systems, and technology demonstrators have been developed by research institutions, universities, and industry. The use of different types of illuminators, ranging from analogue FM-radio, analogue TV over digital broadcasters like digital audio broadcast (DAB), digital video broadcast-terrestrial (DVB-T) to cell-phone base stations, and WiFi and satellite-borne transmitters has been considered. The different illuminator systems are characterised by individual strengths and weaknesses with respect to radar requirements, and fields of application have been identified for the different sensor types.