1 Wideband Synthetic Aperture Beamforming for Through-the-Wall Imaging

Through-the-wall radar imaging (TWRI) and sensing is emerging as an important area of research and development [1]-[6]. A TWRI system provides enhanced situational awareness in operational environments for a variety of civilian and military applications. In particular, a TWRI system facilitates real-time information-gathering and intelligent decision-making about the contents of the indoor scene. Compared to other radar applications, TWRI faces unique challenges due to signal propagation through walls. The composition and thickness of the wall, its dielectric constant, and the angle of incidence affect the strength and characteristics of the propagating signal. The change in propagation speed and wave refraction must be taken into account for effective and accurate imaging. Failure to do so would cause undesirable errors in determining the nature and the locations of the targets behind walls. In this lecture note, we present a synthetic aperture beamforming approach that uses ray perturbation theory to account for the effects of transmission through a single uniform wall. RELEVANCE Through-the-wall beamforming discussed in this lecture note, and imaging and sensing through walls, in general, can be used in search and rescue missions, surveillance and reconnaissance, an