Sinan Gezici Zafer Sahinoglu Andreas F. Molisch Hisashi Kobayashi H. Vincent Poor A Two-Step Time of Arrival Estimation Algorithm for Impulse Radio Ultra Wideband Systems http://arxiv.org/abs/cs/0507006 2005 CoRR abs/cs/0507006 db/journals/corr/corr0507.html#abs-cs-0507006 informal publication