Ultrasound Transducers for Large-Scale Metrology: A Performance Analysis for Their Use by the MScMS

The Mobile Spatial coordinate Measuring System (MScMS) is a distributed wireless-sensor-network-based system used to perform dimensional measurements of large-scale objects. The system consists of a wireless mobile probe with ultrasonic (US) transceivers, the position of which is determined using a distributed constellation of US transceivers arranged around the measuring area. These US transceivers, which are known as Crickets, transmit US signals to each other and measure their time of flight (TOF) to determine the mutual distances. The MScMS is able to calculate the Cartesian coordinates of the object surface points touched by the wireless mobile probe. This paper aims to experimentally evaluate the performance of the US transducers on each of the MScMS Crickets. The experiments are designed and performed by means of a statistical factorial plan to identify the most important factors affecting the transducers' performance on TOF measurements. Particular attention is given to the error derived by the US signal attenuation and the method of US pulse detection. The results are analyzed in detail and fully interpreted. Finally, some considerations about possible actions to improve the MScMS measuring system are given.