Development of a triaxial pressure-velocity probe for deep submergence applications

• Published in: The Journal of the Acoustical Society of America 2006-05, Vol.119 (5_Supplement), p.3445-3445
• Main Authors: McConnell, J. A., Lopath, P. D., Jensen, S. C., Trivett, D. H., Biesel, V. B., Caspall, J. J., McEachern, J. F., Coughlan, R.
• Format: Article
• Language: English
• Subjects: Marine
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4786959

A triaxial pressure-velocity probe has been developed for the purpose of measuring the ambient acoustic noise field in the ocean at frequencies below 500 Hz. The probe consists of an omnidirectional hydrophone, a compliantly suspended sphere containing a triaxial geophone, and an electronics housing that contains a four-channel preamplifier and a digital compass. All of these components are packaged in a frame which in turn is attached to a deployment cable (i.e., a strength member) and submerged to a prescribed depth. The performance specifications for the transducers include a submergence depth rating of 6 km and a noise floor of 40 dB re: 1 mPa2 per hertz. These two parameters essentially drive the design of the probe and the paper will address these topics from the standpoint of the design evolution that took place in order to meet the specifications. Other aspects of the probe’s development include efforts to mitigate flow-induced noise and shielding the compass from the magnetic field emitted by the geophones. Test data obtained on a prototype unit will be presented. [Work supported by C. M. Traweek at the Office of Naval Research Code 321MS.]