This paper presents an experimental study of localisation of a body mounted ultra-wideband (UWB) antenna. Several three-dimensional localisation experiments have been performed, using a miniature tapered-slot antenna mounted on the human body as a mobile station and three Vivaldi antennas as base stations, to comprehend the level of accuracy that can be achieved and assess how precisely the tiny movements of the mobile station could be resolved. Time of Arrival data fusion and peak detection techniques have been used to compute the position of the target node in terms of x, y, z cartesian coordinates. The antennas are envisioned to be employed in a pulse based time-of-flight motion tracking system, using the upper end of the UWB band. The geometry and performance of a UWB Vivaldi antenna designed for the project is also presented.