Experimental results of passive imaging of moving continuous broadband sound sources within a sensor field

Document type: Journal Articles
Article type: Original article
Peer reviewed: Yes
Full text:
Author(s): Viktoria Tegborg, Mats Pettersson, Ingvar Claesson
Title: Experimental results of passive imaging of moving continuous broadband sound sources within a sensor field
Journal: IEEE journal of oceanic engineering : a journal devoted to the application of electrical and electronics engineering to the oceanic environment
Year: 2011
Volume: 36
Issue: 1
Pagination: 26-37
ISSN: 0364-9059
Publisher: IEEE
URI/DOI: 10.1109/JOE.2010.2066790
ISI number: 000288683100003
Organization: Blekinge Institute of Technology
Department: School of Engineering - Dept. of Electrical Engineering (Sektionen för ingenjörsvetenskap - Avd. för elektroteknik)
School of Engineering S-371 79 Karlskrona
+46 455 38 50 00
Authors e-mail: viktoria.tegborg@bth.se, viktoria.tegborg@gmail.com
Language: English
Abstract: Sparsely distributed sensors or sparse arrays can be associated with high positional accuracy and capability for large area surveillance. This paper shows, both through simulations and with real measurement data, that sparse sensor systems can be used to accomplish high-performance underwater surveillance. The paper focuses on measurement setups with several passive single hydrophones placed hundreds of meters apart in a water depth of dozen of meters. By such a setup, a sound source is more likely to move inside the array, and thus near-field processing can be considered. The sensor pairs will also be located in different directions in relation to the sound source. These two prerequisites give the possibilities to high spatial resolution. Images of the coherent sound activity for different sensor pairs are formed, and every sensor pair map is summarized into a resulting map. In this way, an arbitrary number of sound sources of a target can be resolved. Good correlation results are shown even when the sound sources are at the same distance as the baseline of the sensor pairs. This is achieved by Doppler compensating for target movement and also by whitening of the cross spectra. The analyses of the measurements also show that baseline-dependent bandwidth can improve the results. In this paper, it is indicated from experimental data that two propeller sound sources could be resolved, and in another measurement setup, the engine could be separated from the propellers.
Subject: Signal Processing\Radar and Sonar
Technoscience Studies\Innovation System and Development
Keywords: Underwater acoustics, Acoustic imaging, Acoustic measuring instruments, Imaging systems, Signal processing, Sonar, Underwater imaging