Wideband synthetic aperture beamforming for through-the-wall imaging

A synthetic aperture beamforming approach that uses ray perturbation theory has been presented to account for the effects of transmission through a single uniform wall. The design of the beamformer incorporates the effects of the wall through which the imaging system is looking. These effects include the reduction in propagation and speed and wave refraction. An approach using planar arrays for extending the 2D to 3D through-the-wall beamforming has also been discussed. This additional feature is instrumental to effective target identification and classification. Lastly, two techniques for mitigating the detrimental effects of unknown walls in imaging quality and reliability have been proposed using the bias in imaged target location when incorporating incorrect walls and the effect of wall ambiguities on the target spread and intensity profile.