@conference {743, title = {Optimal test-point positions for calibrating an ultrasonic LPS system}, booktitle = {13th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA 2008)}, year = {2008}, month = {09/2008}, pages = {338-344}, author = {Daniel Ruiz and Ure{\~n}a, J. and Jos{\'e} Manuel Villadangos and Gude, I. and J.J. Garcia and {\'A}lvaro Hern{\'a}ndez and Ana Jimenez} }