@conference {212, title = {Relative positioning system using simultaneous round trip time of flight measurements.}, booktitle = {11th IEEE Int. Conf. on Emergy Technologies and Factory Automation (ETFA 2006)}, year = {2006}, month = {09/2006}, pages = {602 - 605}, address = {Praga, Rep{\'u}blica Checa}, isbn = {1-4244-0881-1}, author = {Carlos De Marzziani and Ure{\~n}a, J. and Manuel Mazo and {\'A}lvaro Hern{\'a}ndez and J.J. Garcia and Ana Jimenez and Mar{\'\i}a del Carmen Perez and Alberto Ochoa and Jos{\'e} Manuel Villadangos} }