Illuminator of Opportunity Localization for Digital Broadcast-Based Passive Radar in Moving Platforms

This article addresses the problem of illuminator of opportunity (IO) localization for digital broadcast-based passive radar (PR) on moving platforms. Due to the orthogonal frequency division multiplexing (OFDM) modulation, digital broadcast [DTMB, digital video broadcasting terrestrial (DVB-T), and digital audio broadcasting (DAB), etc.] signals have a periodic structure. Using the periodic structure of the signal, we propose a digital broadcast IO localization method by a single PR on a moving platform, including a fine time of arrival (TOA) estimation and a closed-form IO localization solution. Taking the DTMB signal as an example, a fine TOA estimation method is proposed using the time-domain pseudorandom noise sequence. Simulation analyzes show that the fine TOA estimation method can obtain an accuracy close to that of Cramér–Rao lower bound (CRLB), and it is robust to multipath environments and Doppler. The closed-form IO localization solutions for the linear track case and nonlinear track case are derived using the two-step weighted least squares method. Field testing campaigns of TOA estimation on the stationary platform are carried out, and the TOA estimation accuracy can reach 0.1 m in practical environments. A digital broadcast IO localization experiment is carried out in Northwest China, and the effectiveness of the location method is demonstrated.