Precision Improvement and Reduction of Blind Zones in Ultrasonic Transducers Golay Complementary Sequences
Amélioration de la Précision et Réduction des Zones Masquées de Capteurs À Ultrasons Grâce À l'Utilisation de Séquences Complémentaires de Golay
OPEN ACCESS
Sensorial systems based on ultrasonic transducers present some constraints,which reduce their performances. Typical problems are low precision in measurements,and the existence of a blind zone in front of transducers,where reflectors can not be detected if transducers are used as emitters and receivers. In order to improve the precision achieved by these transducers,binary sequences are often used to code the emission,so afterwards,distances can be determined using correlation techniques. The usage of Golay complementary sequences allows to increase remarkably the precision obtained by an isolated ultrasonic transducer. Also,it permits to eliminate the mentioned blind zone,thanks to their auto-correlation characteristics. These two features are very interesting in order to use ultrasonic transducers in more complex sensorial associations.
Résumé
Les systèmes sensoriels basés sur les capteurs à ultrasons présentent certaines contraintes qui ont tendance à réduire leur performance. Parmi les problèmes typiques, nous pouvons citer la faible précision des mesures et l'existence à l'avant des capteurs de zones masquées, zones où les réflecteurs ne peuvent pas être détectés si les capteurs sont utilisés comme émetteurs et récepteurs. Dans le but d'améliorer la précision des mesures réalisées par ces capteurs, les émissions sont le plus souvent codées par des séquences binaires. Les distances peuvent être alors déterminées en faisant appel à des techniques de corrélation. Dans ce cadre, ce travail présente les résultats obtenus lors de l'utilisation de séquences complémentaires de Golay, lesquelles permettent d'augmenter de manière significative la précision obtenue à partir d'un capteur à ultrasons isolé. Elles permettent également d'éliminer les zones masquées précédemment citées grâce à leurs caractéristiques d'autocorrélation.Ces deux fonctions seront très intéressantes dans l'optique d'une utilisation de capteurs à ultrasons dans le cadre d'associations sensorielles plus complexes.
Ultrasonic sensorial systems, Golay complementary sequences, precision improvement, reduction of blind zones.
Mots clés
Systèmes sensoriels à ultrasons,séquences complémentaires de Golay,amélioration de la précision,réduction des zones masquées.
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