  We present a novel device-free stationary person detection and ranging
method, that is applicable to ultra-wide bandwidth (UWB) networks. The method
utilizes a fixed UWB infrastructure and does not require a training database of
template waveforms. Instead, the method capitalizes on the fact that a human
presence induces small low-frequency variations that stand out against the
background signal, which is mainly affected by wideband noise. We analyze the
detection probability, and validate our findings with numerical simulations and
experiments with off-the-shelf UWB transceivers in an indoor environment.
