Ultrasonic smart sensors the importance of the measurement principle

This paper deals with the role of the measurement principle in the concept of smart sensors. The latter will ideally provide metrological characteristics adjusted according to the task context. As shown in section two, to attain this objective, the sensor requires an intelligent measurement method, i.e. a method which provides many measures related to the sensed entity in order to validate the acquired value, and many independent and sensitive parameters in order to control the performances of the sensor as regards detection and estimation. This approach is then applied to ultrasonic range finding systems. Two implementations, using respectively a pulse echo method and a frequency modulated method are described and compared in the sense of their intelligence capabilities. The study concludes to the superiority of the frequency modulated method and to the interest of disposing of symbolic information to improve the measurement process