Acoustic signature of an AUV

In this presentation further results from an experimental analysis of the acoustic signature of an Ocean Explorer class AUV are presented. The results to be presented include, data collected in an open water environment with the AUV operating at cruising speed, measurements performed in a reverberant test tank on an AUV model, and measurements in the reverberant test tank of an AUV under typical operating conditions. Different operating conditions and different mountings for the main propulsion and control module (podule) inside the AUV are considered. Inside the podule are the propulsion motor and the motors for the control surfaces with penetrations for the main propulsion shaft and the shafts for the control surfaces. Considered in the measurements is the influence of the propeller, the mounting of the podule, and the covering the podule with a compliant layer. It is shown that for the type of AUV considered here, the type of mounting of the podule is not very significant and that significant energy is transferred through the water trapped in between the podule and the AUV hull. Furthermore, the propeller has a significant influence on the acoustic signature.