A noncoherent approach to radar localization through unknown walls

A simple and practical noncoherent approach to through-the-wall radar detection and localization in the presence of unknown walls is presented. The technique corrects for the shifts introduced in target location estimates due to ambiguities in the wall thickness and dielectric constant. Data is collected using three independent monostatic single-antenna radar units, employing stepped-frequency signals, at two or more different standoff positions of the radar system from the wall. In post-data acquisition processing, one of the wall parameters assumes a fixed value. Localization is then performed, for different assumed values of the other parameter at different standoff positions, using a trilateration-based technique that incorporates the presence of the wall. Target displacement trajectories, each corresponding to a different standoff position, are then formed and the cross-over point is estimated to be the target location. The results show that the radar system is able to correctly locate targets behind unknown walls.