In this paper, an ultra-wideband (UWB) synthetic aperture radar system that can perform 3D localization of objects is implemented. The system consists of a moving platform that positions two UWB horn antennas. The 3D image construction is performed using the delay-sum beamforming algorithm. Experiments were performed using two data acquisition techniques, namely, background measurements technique and change detection. The former can be used for imaging stationary targets while the latter is applicable for moving objects. At different distances and orientations from the antennas, various targets were imaged. Through-wall imaging was also considered. The system is augmented with a graphical user interface that allows the user to change input parameters and display a 3D image of the target along with plots of frequency and time analysis at different antenna positions. The results demonstrate the system applicability for many indoor applications.