“…Background and Motivation P ASSIVE radar network systems have recently received a growing interest, which use signals of opportunity such as television broadcasts [1], frequency modulation (FM) Manuscript M. Sellathurai is with the School of Engineering and Physical Sciences, Herriot Watt University, Edinburgh EH14 4AS, U.K. e-mail: mathini@ieee.org. commercial radio [2], global positioning system (GPS) [3], universal mobile telecommunications systems (UMTS) [4][5][6], and WiFi [7], as illuminators for target detection, estimation, and classification. Since only receivers are required in passive radar networks, they have the advantages of low probability of intercept (LPI) [8][9][10] and low implementation costs.…”