Optimizing Installation and Operation Properties of an AUV-Mounted Swath Sonar Sensor for Automated Marine Gas Seep Detection – a Modelling Approach

Tuesday, 16 December 2014
Stefan Wenau1, Tai Fei1, Zsuzsanna Tóth2, Hanno Keil2, Volkhard Spiess2 and Dieter Kraus3, (1)MARUM - University of Bremen, Bremen, Germany, (2)University of Bremen, Bremen, Germany, (3)Bremen University of Applied Sciences, Institute of Water-acoustics, Sonar Engineering and Signal Theory, Bremen, Germany
The detection of gas bubble streams in the water column by single- and multibeam sonars has been a common procedure in the research of marine seep sites. In the framework of the development of an AUV capable of automatic detection and sampling of gas bubble streams, such acoustic flares were modelled in MATLAB routines to assess the optimal sonar configuration for flare detection. The AUV development (IMGAM-project) is carried out as a cooperation of the company ATLAS Hydrographic and the MARUM at the University of Bremen. The combination of sensor inclination, sonar carrier frequency and pulse characteristics affect the ability of the system to detect bubble streams of different sizes and intensities. These variations in acoustic signal return from gas bubble streams depending on acquisition parameters can affect the detectability and acoustic properties of recorded acoustic flares in various seepage areas in the world’s oceans. We show several examples of acoustic signatures of previously defined bubble streams under varying acquisition parameters and document the effects of changing sensor parameters on detection efficiency.