Multibeam Advisory Committee (MAC) – Three Years of Working Towards the Consistent Acquisition of High Quality Multibeam Echosounder Data Across the US Academic Fleet

Abstract:

In 2010 the National Science Foundation (NSF) held a meeting to address the variability in quality of multibeam echosounder (MBES) data for ships of the US Academic Fleet. The participants of this meeting identified that there was a strong need to coordinate operational efforts for multibeam data acquisition across all vessels of the fleet. To address this need, the University of New Hampshire’s Center for Coastal and Ocean Mapping joined with Lamont-Doherty Earth Observatory in submitting a proposal to NSF to form the Multibeam Advisory Committee (MAC), which was funded in the fall of 2011.

The MAC through the last three years has assembled a team of experts who have been called upon to respond to questions about MBES data acquisition and data quality, conduct shipboard assessments of MBES systems, create documentation supporting best practices for multibeam acquisition and data workflow, and to develop tools to support both data acquisition and quality assessment. Tools and techniques developed through the MAC include:

• SVP Editor – a graphical display and editing program for SVP, CTD, XBT, and XSV data. This program integrates directly with multibeam acquisition software to both receive navigation and depth information, used during the processing of the sound velocity data, and also has the ability to send edited and processed cast directly to the sounder.
• MBES Accuracy and Swath Performance Tools - tools which can assess both the accuracy of MBES bathymetric data as compared to a reference surface grid and to examine swath width performance of MBES systems as a function of depth.
• Remote Patch Test Support - the MAC provides patch test site selection, detailed execution plans, and tools to support the transmittal of a downsized raw MBES data files from ships over satellite in order to determine the angular offset values (pitch, heading, and roll) for MBES systems with no MAC personnel on board. 
• Built In Self Test (BIST) Evaluation Tools – tools which can plot and evaluate BIST data including TX and RX array impedance and noise assessment.

While these tools and techniques were developed specifically to address the needs of collecting high quality MBES data for ships of the US Academic fleet, they can and have been used for other MBES systems outside of the fleet.