ABSTRACT
This chapter describes the technologies that deal with imaging, localizing, and tracking behind-the-wall targets, which are either stationary or in motion, using an array with collocated or distributed apertures. There is a wide variety of potential applications for through-the-wall imaging systems that come with different performance requirements. Radar imaging achieves its range and cross-range resolutions of targets through the exploitation of, respectively, the bandwidth of the signals and the aperture of an array of sensors used in the operation. Target localization can be based on the combination of the direction of arrival (DOA) and range information measured at one or multiple positions, or range-only or DOA-only information measured at multiple positions through, respectively, trilateration and triangulation. When moving targets are of interest, an appropriate use of the time–frequency analysis of the Doppler signatures can facilitate significant signal-to-noise ratio enhancement, clutter suppression, and target separation and discrimination.
