Study On Passive Radar Imaging Of Static Targets And Moving Targets Using Distributed Apertures

With the increase of the types and numbers of the illuminators of opportunity in the modernsociety, such as broadcasting stations, mobile phone base stations, communication satellites, etc.,passive radar detection and imaging using illuminators of opportunity has emerged as an active areaof research in recent years. In this paper, passive radar imaging methods of static targets and movingtargets using distributed apertures are studied.A signal model of passive radar using distributed apertures is presented for static targets, which isbased on the Green’s function of the background environment and therefore is applicable to thefree-space and multipath environments. This model doesn’t require the prior knowledge of thetransmitter. Then, a binary-hypothesis-testing-based imaging method is investigated where a spatial-resolved test-statistic is determined according to the signal-to-noise-ratio (SNR) maximization criteria.The resulting image is formed by the test-statistic evaluated at each hypothesized target location. Theperformance of the imaging method in free-space and multipath environments are analyzed in detail.The narrow pulsed signal is used to demonstrate the performance of the imaging method in free-space.The linear frequency modulation (LFM) signal and the digital video broadcast-terrestrial (DVB-T)signal are used to demonstrate the performance of the imaging method in multipath envoronments.The targets of interests may be in motion. Therefore, the imaging approach of static targets isextended to apply for moving targets and we focus on the imaging method in free-space. New passiveradar imaging using distributed apertures of moving targets is proposed by using the signal model ofpassive radar. The image is formed by using the spatial-and velocity-resolved test-statistic based onthe binary-hypothesis-testing imaging method. The resulting image is formed by the test-statisticevaluated at each hypothesized target location and target velocity. We analyze the spatial and velocityresolution in terms of the four-dimensional point spread function. The single-frequency continuouswave (CW) and the linear frequency modulated continuous wave (LFMCW) are used to demonstratethe performance of the passive imaging method. The theoretical analysis and experimental resultsshow that the targets can be reconstructed correctly in the image formed by the spatial-and velocity-resolved test-statistic.