Title :
A technique for calibration of monostatic echosounder systems
Author :
Vagle, Svein ; Foote, Kenneth G. ; Trevorrow, Mark V. ; Farmer, David M.
Author_Institution :
Inst. of Ocean Sci., Sidney, BC, Canada
fDate :
7/1/1996 12:00:00 AM
Abstract :
A calibration technique has been adapted to render complete system calibrations of high-frequency acoustical instrumentation. This is based on standard targets; specifically, precisely manufactured spheres composed of tungsten carbide with 6% cobalt binder. The use of multiple sphere sizes was found to be advantageous, both as an independent check of the calibrations, and so that resonances in the sphere responses at certain frequencies could be avoided. Complete system gains and beam patterns, which include effects of bandpass filters and finite-pulse lengths, were determined by moving the spheres individually in the transducer far-fields. Use of this procedure ensures control over the acoustical characteristics of transducers, which may change from the time of manufacture and first testing due, for example, to platform mounting. It also provides a direct means of measuring the sampling volume at relatively high and constant signal-to-noise ratios. Implementation of this technique is discussed using a multifrequency sonar system as an example
Keywords :
acoustic transducers; band-pass filters; calibration; cobalt; signal sampling; sonar; tungsten compounds; Co binder; WC; acoustical characteristics; bandpass filters; bubble sizes; calibration; constant signal-to-noise ratio; finite-pulse lengths; fish; high-frequency acoustical instrumentation; monostatic echosounder; multifrequency sonar; multiple sphere sizes; platform mounting; standard targets; transducer far-fields; Acoustic beams; Acoustic transducers; Band pass filters; Calibration; Cobalt; Frequency; Instruments; Manufacturing; Resonance; Tungsten;
Journal_Title :
Oceanic Engineering, IEEE Journal of