Seabed reflection measurement uncertainty
Abstract
The seabed reflection coefficient is a fundamental property of the ocean waveguide. Measurements of the frequency and angular dependence of the reflection coefficient can provide information about the geoacoustic properties of the seabed or can be used as an input to propagation models. The uncertainty of the measurements must be known in order to determine prediction uncertainties for the acoustic field and/or the geoacoustic properties. Analysis indicates that the reflection measurements have a standard deviation from +/0.51 dB at full angular resolution depending on frequency and experiment geometry. The dominant contribution to the error is source amplitude variability, and a new processing approach was developed that reduces the error for frequencies above a few hundred Hz. Further reduction in the uncertainty can be obtained by averaging in angle, for example, a +/1° angle averaging leads to a standard deviation of less than +/0.5 dB. Errors in the angle estimate are a few tenths of a degree from 034° grazing angle: the crucial angular range for predicting longrange propagation or for geoacoustic property inversion.
 Publication:

Acoustical Society of America Journal
 Pub Date:
 October 2003
 DOI:
 10.1121/1.1605388
 Bibcode:
 2003ASAJ..114.1861H
 Keywords:

 acoustic wave reflection;
 underwater acoustic propagation;
 acoustic waveguides