A survey of transducer and sonar electroacoustic test and calibration facilities in the U.S.A.

Underwater electroacoustic measurements are made in test facilities which typically provide an environment that allows free-field (a homogenous isotropic medium free of boundaries) and/or far-field (where the pressure is a spherically diverging wave) conditions. Though some testing can be completed in the near-field (where the spherical wave is not sufficiently planar), this is a less common technique. Free-field facilities can be large-size natural sites such as lakes, ponds and quarries, allowing tests at low frequencies, and also smaller man-made indoor or outdoor tanks. A few facilities allow additional test capabilities, in addition to the classical electroacoustic tests, by introducing extreme hydrostatic pressure and temperature conditions. In addition to their internal projects, the government-owned test facilities offer services to companies such as CTG/ITC to test and calibrate their products. In this paper, transducer and sonar test facilities, and their capabilities are presented. There are other commercial or privately owned test facilities providing similar or other services but these are not covered in this paper.