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Improved Active Sonar Tactical Support by Through-the-Sensor REA

Author: Abrahamsson, L. · Andersson, B.L. · Ivansson, S. · Pihl, J. · Ainslie, M.A. · Benders, F.P.A. · Chalindar, B. · Colin, M. · Cristol, X. · Dybedal, J. · Eidem, E.J. · Juhel, B. · Olsen, G.K. · Vossen, R. van
Type:article
Date:2011
Source:Proceedings 4th International Conference and Exhibition on Underwater Acoustic Measurements - Technologies & Results - UAM 2011, 20-24 June 2011, Kos, Greece
Identifier: 464503
Keywords: Reverberation · Inversion · Mean grain size · Rapid environment assessment REA · Defence Research · Defence, Safety and Security · Physics & Electronics · AS - Acoustics & Sonar · TS - Technical Sciences

Abstract

Reverberation is a problem for active sonar operating in shallow waters, reducing detection probabilities and introducing false alarms. Within the European Defence Agency project Rumble-2, a demonstrator system has been developed for ”through the sensor” measurement of the bottom parameters needed to predict active sonar detection performance. An operational low-frequency active sonar is used along with a real-time inversion method. The demonstrator is a self-contained unit that reads sonar data without interfering with the on-going sonar operation. Several sea trials have been performed demonstrating its good performance. The inversion results are consistent with ground truth. Moreover, similar results are obtained for trials in the same area with quite different environmental conditions. The demonstrator tool is based on several simplifying assumptions, such as range independence and a homogeneous half-space bottom. Off-line studies, made with a sediment layer, show that the effects of a range dependent bathymetry are small in the survey area. In addition, it is shown that inversion for a grain size parameter and utilization of regression formulas for sediment sound speed and absorption are useful for stabilizing some inversion parameters.