ABSTRACT
This chapter describes our research on wideband piezoelectric transducers and microelectromechanical systems (MEMS) sensors for ultrasonic in-air applications. It describes the wideband transducers and sensor arrays investigated in our work and evaluate their performance. The chapter discusses use of the transducers and sensor array in an indoor ultrasonic local positioning systems (LPSs). It reviews of ultrasonic in-air transducer technologies was presented. The chapter describes how MEMS sensors can be used to construct ultrasonic receiver arrays. It considers use of piezoelectric transducers and MEMS sensors as wideband ultrasonic transmitters and receivers for mobile applications. The chapter describes characterization of four modified transmitters and a receiver array. It develops a prototype indoor ultrasonic LPS based on the transducers and sensors. Ultrasonic LPSs are distinguished by their ability to estimate location with a high degree of resolution at low cost. Experiments were conducted to assess the performance of the LPS in estimation of beacon-mobile devices range.
