A Theoretical and Experimental Investigation of Acoustic Dyadic Sensors
Abstract
This report sets the groundwork for a generalized theory of directional sensors using the Taylor series of the acoustic pressure; it moves from the basic pressure sensor to the vector sensor, on to the dyadic sensor, then on to higher-order sensors depending on the number of terms in the Taylor series. A benefit of higher-order sensors is improvement in the 3-dB beamwidth; 105 degrees for a vector sensor, 65 degrees for a dyadic sensor. An analysis shows: (1) how finite-difference approximations can be utilized to estimate the 10 terms that define the dyadic sensor, (2) it is not prudent to employ finite differences to the estimation of 2nd-order partial derivatives of the pressure, (3) a dyadic sensor be realized with 18 accelerometers and a pressure sensor and (4) that this realization requires only 1st-order finite differences, which can be performed in the pressence quantization and wide band noise effects. A partial dyadic sensor (three orthogonal accelerometer dipoles and a pressure sensor at the origin) was tested at Seneca Lake during May 2001. The experimental in-water beam pattern measurements confirmed theoretical predictions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 25, 2001
- Accession Number
- ADA393376
Entities
People
- Manuel T. Silvia