<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">José Manuel Villadangos</style></author><author><style face="normal" font="default" size="100%">Ureña, J.</style></author><author><style face="normal" font="default" size="100%">J.J. Garcia</style></author><author><style face="normal" font="default" size="100%">Manuel Mazo</style></author><author><style face="normal" font="default" size="100%">Álvaro Hernández</style></author><author><style face="normal" font="default" size="100%">Ana Jiménez</style></author><author><style face="normal" font="default" size="100%">Ruíz, Daniel</style></author><author><style face="normal" font="default" size="100%">Carlos De Marzziani</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Measuring Time-of-Flight in an Ultrasonic LPS System Using Generalized Cross-Correlation</style></title><secondary-title><style face="normal" font="default" size="100%">Sensors</style></secondary-title><short-title><style face="normal" font="default" size="100%">Sensors</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">generalized cross-correlation; ultrasonic LPS; phase transform; Kasami codes</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year><pub-dates><date><style  face="normal" font="default" size="100%">11/2011</style></date></pub-dates></dates><pub-location><style face="normal" font="default" size="100%">Basilea</style></pub-location><volume><style face="normal" font="default" size="100%">11</style></volume><pages><style face="normal" font="default" size="100%">10326 - 10342</style></pages><language><style face="normal" font="default" size="100%">English</style></language><abstract><style face="normal" font="default" size="100%">In this article, a time-of-flight detection technique in the frequency domain is described for an ultrasonic Local Positioning System (LPS) based on encoded beacons. Beacon transmissions have been synchronized and become simultaneous by means of the DS-CDMA (Direct-Sequence Code Division Multiple Access) technique. Every beacon has been associated to a 255-bit Kasami code. The detection of signal arrival instant at the receiver, from which the distance to each beacon can be obtained, is based on the application of the Generalized Cross-Correlation (GCC), by using the cross-spectral density between the received signal and the sequence to be detected. Prior filtering to enhance the frequency components around the carrier frequency (40 kHz) has improved
estimations when obtaining the correlation function maximum, which implies an
improvement in distance measurement precision. Positioning has been achieved by using hyperbolic trilateration, based on the Time Differences of Arrival (TDOA) between a reference beacon and the others.</style></abstract><issue><style face="normal" font="default" size="100%">11</style></issue></record></records></xml>