Ocean acoustic propagation modelling in the vicinity of submerged structures

O.C. Rodríguez1,2, orodrig@ualg.pt
A. Silva1,2, asilva@ualg.pt
S.M. Jesus1,2, sjesus@ualg.pt
1LARSyS, IST, Lisbon
2University of Algarve
Campus de Gambelas, PT-8005-139 Faro, Portugal

Autonomous underwater vehicle (AUV) navigation heavily relies on point-to-point acoustic communications with a surface ship or with underwater companions. Transmission and reception of acoustic packets depends significantly on the impulse response of the acoustic channel which, as relative distances increase, can be described by acoustic propagation models well designed for the underwater environment. In complex environments, as near submerged structures, underwater canyons or Sea Mountains the reflection of sound energy from the bottom, walls and sea surface induces a complex behaviour of the impulse response, whose anticipation is of main importance for the prediction of communications performance and for mission planning. The communication performance of two AUVs, navigating in formation for the inspection of an underwater canyon, is evaluated through simulations over a real bathymetry, using a two-dimensional (2D) and a three-dimensional (3D) acoustic propagation models. The behaviour of 2D and 3D models is analysed in terms of eigenrays and corresponding impulse responses, and the communication performance is evaluated considering the resulting inter-symbolic interference and impulse response lengths.

Work supported by LARSys - PEst-OE/EEI/LA0009/2013