Acoustical properties of an immersed corner-cube retroreflector alone and behind screen for ultrasonic telemetry...

Ultrasonic telemetry measurements consist in remotely detecting and locating an object. To maximize the signal-to-noise ratio, a target may be used, positioned at a reference point. In this framework, the ultrasonic reflective characteristics of a corner-cube retroreflector (CCR) are investigated. The most interesting property of a CCR is its ability to fully reverse an incoming wave in the same direction under certain conditions. Theoretical developments are performed in order to understand its acoustic behaviour, and experimentations are made in various configurations: CCR alone in water, and behind an immersed plate that acts as a screen, with normal and non-normal incidence. The results highlight its strong performance. Moreover, the study of two other couples of CCR material and surrounding fluid underlines the relevance of considering the acoustic properties of each medium, as they have a strong influence on the acoustic response of the CCR.