TY - CONF T1 - Ultrasonic beacon-based Local Positioning System using Loosely Synchronous codes T2 - 5th IEEE International Symposium on Intelligent Signal Processing (WISP2007) Y1 - 2007 A1 - María del Carmen Perez A1 - Ureña, J. A1 - Álvaro Hernández A1 - Carlos De Marzziani A1 - Ana Jimenez A1 - José Manuel Villadangos A1 - Fernando J. Álvarez KW - Acoustic LPS KW - asynchronous detection KW - DS-CDMA KW - IFW KW - ISI KW - LS-codes KW - MAI. AB - This work presents the development of a Local Positioning System (LPS), based on the transmission of ultrasonic signals, which have been previously encoded by Loosely Synchronous (LS) codes. The LPS consists of several ultrasonic emitters located at known positions in the environment, and of a portable receiver that computes its position by measuring the Differences in Times of Arrival (DTOA) between a reference emitter and the others. LS codes exhibit an %Zero Correlation Zone (ZCZ) Interference Free Window (IFW) in the auto-correlation and cross-correlation functions. Therefore, if the relative time-offset of the codes are within the IFW, it is possible to have simultaneous emissions without interference, as well as to reduce the multipath effect. JF - 5th IEEE International Symposium on Intelligent Signal Processing (WISP2007) PB - IEEE CY - Alcalá de Henares, España VL - 1 SN - 1-4244-0829-6 UR - http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4447594 ER -