@conference {, title = {Android application for indoor positioning of mobile devices using ultrasonic signals}, booktitle = {2016 International Conference on Indoor Positioning Systems.}, year = {2016}, month = {10/2016}, pages = {1-10}, publisher = {IEEE}, organization = {IEEE}, address = {Alcala de Henares, Espa{\~n}a }, isbn = {978-1-5090-2425-4/16}, author = {Mar{\'\i}a del Carmen Perez and D.Gualda and E. Diaz and P. Pajuelo and Jos{\'e} Manuel Villadangos and Ure{\~n}a, J. and E. Garcia} }