Sonar array measurement facility

Abstract

DED has developed a facility for the accurate calibration of towed line sonar arrays which is small and noise immune enough that it can be installed at any site requiring such measurements. The facility consists of a series of cylindrical transducers submerged in a water tank. The array under test is pushed through the transducers and the free field voltage sensitivity of each channel is measured one-at-a-time by comparison against some of the transducers. The remaining transducers project acoustical energy into the water. This facility is an outgrowth of a concept developed by NRL/USRD [J. F. Zalesak and W. J. Trott, J. Acoust. Soc. Am. 62, 91–101 (1977)]. Within limits, the accuracy of this facility meets the requirements of the Navy's towed line arrays. Typically, between 20 Hz and 2 kHz, measurements are repeatable within ±0.7 dB and correlate with the Navy's measurements within ±0.7 dB. During the past three years, the facility has performed over 3000 measurements and is presently under development as a product line.