Abstract: The invention is an improved guided wave level measurement device. A guided wave measuring device includes a waveguide, a signal generator and a signal receiver, where the signal generator and signal receiver are operationally connected to the waveguide. The improvement included a target which is displaceable with respect to the waveguide and coupled to the waveguide. The target presents a reflective surface and the position of the target is detectable through time of flight measurements of a signal generated by the signal generator.