Next Article in Journal
Biochemical Markers for Assessing Aquatic Contamination
Next Article in Special Issue
Tactile Fabric Panel in an Eight Zones Structure
Previous Article in Journal
Mapping and Assessment of Degraded Land in the Heihe River Basin, Arid Northwestern China
Previous Article in Special Issue
Flexible Time-Triggered Sampling in Smart Sensor-Based Wireless Control Systems
Sensors 2007, 7(11), 2579-2598; doi:10.3390/s7112579

Determining Position Inside Non-industrial Buildings Using Ultrasound Transducers

2,* , 1
1 TT- Area Electrònica, Enginyeria i Arquitectura La Salle, Quatre Camins 30 08022 Barcelona, Spain 2 Department d’Electrònica, Enginyeria i Arquitectura La Salle, Quatre Camins 30 08022 Barcelona, Spain 3 TT La Salle, Enginyeria i Arquitectura La Salle, Quatre Camins 30 08022 Barcelona, Spain 4 Parc d’Innovació La Salle, Quatre Camins 30 08022 Barcelona, Spain
* Author to whom correspondence should be addressed.
Received: 20 October 2007 / Accepted: 29 October 2007 / Published: 2 November 2007
(This article belongs to the Special Issue Intelligent Sensors)


The position determination inside a building where no GPS signal is beingreceived can be ascertained using laser transmitters in industrial situations where there areno people or using triangulation of the signal strength, normally electro-magnetic signals,if the required accuracy is more than a metre. Our solution is aimed at situations wherepeople are present and where the required accuracy is less than 30 cm, such as in shoppingprecincts or supermarkets. To achieve this, a network of ultrasonic transmitters is fittedinto the ceiling which receives a synchronised time signal. Each transmitter has a uniqueidentifier code and emits its code with a delay with respect to the common time signalwhich is proportional to its code number with an ASK modulation over the ultrasonic bandcentred on 40 KHz. The receivers circulating beneath the transmitters receive the codes ofthose within their detection range, translate the time delays into distances and then obtaintheir position by triangulation since the receivers know the position of every transmitter.Since the receivers are not synchronised with the common time signal or the actual speedof the sound, whose value varies appreciably with temperature, relative humidity andatmospheric pressure, a consecutive approximation algorithm has been introduced. This isbased on the fact that the Z coordinator of the receiver is known and constant and thus it is possible, with only three different identifiers received, to deduce the phase of the common time signal and estimate the speed of the sound with a fourth identifier.
Keywords: Ultrasound; positioning Ultrasound; positioning
This is an open access article distributed under the Creative Commons Attribution License (CC BY) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Share & Cite This Article

Further Mendeley | CiteULike
Export to BibTeX |
MDPI and ACS Style

Escudero, F.; Margalef, J.; Luengo, S.; Alsina, M.; Ribes, J.M.; Pérez, J. Determining Position Inside Non-industrial Buildings Using Ultrasound Transducers. Sensors 2007, 7, 2579-2598.

View more citation formats

Related Articles

Article Metrics

For more information on the journal, click here


Cited By

[Return to top]
Sensors EISSN 1424-8220 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert