Uncertainties and Interdisciplinary Transfers through the End-to-End System (UNITES)
Abstract
The objective of this phase of the project was to characterize the transfer of uncertainties from the acoustic environment to the sonar and its signal processing in probabilistic terms. This involved construction, calibration, and evaluation of uncertainty and variability models for the system and its components. It also involved developing generic methods for efficiently and simply characterizing, parameterizing, and prioritizing variabilities in the end-to-end system (ETES) and uncertainties arising from regional scales and processes. The authors applied a model ETES of modular design to investigate the combined effect of mesoscale structure and short-wavelength internal waves on acoustic transmission loss at low to moderate frequencies in the coastal environment. As a first guess, they viewed the internal wave field as being superimposed on the mesoscale field. Since these two fields can be expected to interact physically as well as acoustically, a proper simulation would account for exchange of energy, momentum, and heat between the mesoscale field and the small-scale internal wave field. The modular design of their prototype ETES system allows them to make incremental but steady progress by increasing the complexity and level of detail represented in each component of the model. In their study of uncertainty due to a random internal wave field, they found that some very small-scale features show differences of the order of 10db between the perturbed and unperturbed cases. The effect of the perturbation on the ray structure is particularly evident in shorter wavelength cases. The differences in the range-averaged transmission losses are smaller, typically a few db at 25Hz, but fields obtained by slightly different methods of range averaging can also differ by a few db.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 15, 2005
- Accession Number
- ADA430211
Entities
People
- Allan Robinson
- Philip Abbot
- Robert N. Miller
Organizations
- Oregon State University