Title
Efficient calculation of broadband acoustic scattering from a partially, obliquely buried cylinder
Author
Nijhof, M.J.J.
Espana, A.
Williams, K.
Publication year
2013
Abstract
An efficient model for the Target In Environment Response (TIER) of buried/half buried, mine-like objects and UXOs is essential for the development and training of automatic target detection and classification methods and for use in sonar performance prediction models. For instance, to investigate the influence of burial depth and orientation on the TIER of an object, a prediction is required for a range of burial depths and object orientation angles. This implies the need for an efficient model since the TIER must be calculated for a considerable number of cases. An efficient computational technique for predicting the TIER of proud, buried, and partially, obliquely buried axially symmetric mine-like objects and UXOs is presented. The method is based on a hybrid model that consists of an incident field model, a Finite Element (FE) model describing the local response of a target, and a Helmholtz-Kirchhoff Integral model describing the resulting wave propagation to greater distances. For most cases of interest, the FE model can be replaced by a lookup table yielding the local response to a set of linearly independent ‘non-physical’ incident fields. Linear combinations of these responses can be used to reconstruct the response of an arbitrary incident field by decomposing it in terms of the components of this pre-calculated set. Test results for an obliquely buried aluminium cylinder demonstrate that the use of a look-up table speeds up the calculation process considerably when multiple Synthetic Aperture Sonar (SAS) runs are simulated, with no loss of accuracy. Typically, building the lookup table can be done in the time needed to evaluate a single SAS run with the FE based model. For the considered case, evaluation of subsequent SAS runs using the lookup table is 20 times faster compared to using the FE based model.
Subject
Physics & Electronics
AS - Acoustics & Sonar
TS - Technical Sciences
Defence Research
Marine
Defence, Safety and Security
Target In Environment Response,
Finite Elements,
Helmholtz Kirchhoff Integral
Unexploded ordnance
buried Objects
Target Detection
Sonar
Underwater acoustics
To reference this document use:
http://resolver.tudelft.nl/uuid:df4c0fcd-37aa-4f4e-987d-0251ca0fe603
TNO identifier
483503
Source
Proceedings of 1st International Conference on Underwater Acoustics (UAC), 23-28 June 2013, Corfu, Greece, 697-702
Document type
conference paper