Abstract

Underwater sound is used as the premier tool to assess the physical and biological processes in the ocean. This field of underwater acoustics enables us to observe quantitatively and more specifically, entail the development and employment of acoustical methods to image underwater features, to communicate information via the oceanic wave guide, or to measure oceanic properties. Thus underwater acoustics encompasses both the science and technology necessary to deploy functioning of acoustical systems in support of both naval and commercial operations.

One of the most important properties of the oceans as far practical applications are concerned lies in their high sensitivity to the propagation of acoustic signals with frequencies especially in the range of 1Hz to 20kHz. Another reason for the practical interest in acoustic propagation in the ocean is the distance that sound can spread which may be of the order of several hundred kilometers. This range is influenced by the local propagation environment, which may vary spatially and temporally. The sound field is 5 dimensional(x,y,z,t,f). Underwater acoustic signals are also prone to losses and noises which affect system efficiency.

As the ocean is so vast, it is a difficult task to accumulate data with space and time unlike shore based system. And the studies are mostly supported with model and simulations. As such the accuracy of a propagation model output relies on representative environmental input data to the model. Bathymetry, seabed properties and sound speed profile, all influence the propagating sound and changes in these parameters may lead to considerable differences in the characteristics of the propagated sound. A variety of three-dimensional and two dimensional underwater sound propagation models with realistic ocean environmental conditions are used for assessing the propagation losses.

For a particular frequency band and environment, the choice of a suitable propagation model can be made. Most modelling efforts are focused to predict the transmission of sound energy or sound pressure. Acoustic models play an important role in the design and optimal deployment of sonar systems. During naval operations, sonar performance estimates often need to be computed in-situ with limited environmental information. This calls for the use of fast acoustic propagation models. Many naval operations are carried out in challenging and dynamic environments. This makes acoustic propagation and sonar performance behavior particularly complex and variable, and complicates prediction. This necessitates the importance of prediction of the response of the natural acoustic environment and the behavior of soundscape. In this proposed research work, it is planned to implement and exploit the models and simulation towards enhancing the detection capability of a submerged object.

Objective

To implement and exploit the models and simulation towards enhancing the detection capability of a submerged object.