Modified Cross-Correlated Back Projection for UWB Through-Wall Surveillance

This paper presents a modified cross-correlated back projection (CBP) algorithm for ultra-wideband (UWB) through-wall surveillance (TWS). Various effects of the wall on through-wall radar imaging, such as wave refraction and change in velocity, result in longer propagation time for a given set of transmitter, pixel and receiver locations. These effects are incorporated into the proposed algorithm. By cross-correlating the outputs of UWB array elements with that of a reference channel located far away from the array center, the presented algorithm can improve the cross-range resolution of the radar images. The capability of the modified CBP algorithm to provide through-wall surveillance is verified using the computed finite-difference time-domain (FDTD) data. Simulation results show that hidden targets behind the wall can be accurately identified in both the range and the direction by using the proposed approach. In comparison to standard BP, this scheme produces images of superior quality with better cross-range resolution and smaller sidelobe levels.