Passive multiarray image fusion for RF tomography by opportunistic sources

The large diffusion of wireless infrastructures in public and private areas is currently stimulating research on surveillance radar systems capable of exploiting network transmissions as potential sources of opportunity. Since these sources are generally narrowband, we propose in this letter a single-frequency approach for imaging targets by using passive arrays deployed around the scattering scene. Single-frequency data allow casting the imaging as an inverse source problem, which avoids the need to retrieve information about the sources prior to imaging. The drawbacks of the highly coarse resolution and blinding effects due to the sources are overcome by employing a multiarray image fusion strategy in conjunction with a change detection scheme for imaging moving targets. The proposed approach is tested via numerical experiments based on full-wave synthetic data corresponding to an indoor scenario.