E/V Nautilus Spring 2014 Quality Assessment Report

Multibeam System: 

Summary and Recommendations

  • As it stands now, the EM302 and associated sensors are working well as compared to other EM302s evaluated recently. The patch test revealed very slight residual angular offsets, indicating a successful reinstallation of the MRU and no apparent change to any other component of the system.

E/V Nautilus Spring 2015 Quality Assessment Report

Multibeam System: 

Summary and Recommendations

  • Heading into the 2015 operating season, the EM302 and associated sensors aboard E/V Nautilus are working well compared to previous evaluations and to other EM302 systems examined recently. The patch test showed no pitch or yaw bias and only a very slight residual angular offset for roll, indicating no major changes to the system geometry.

Falkor Fall 2014 Quality Assessment Report

The EM302 and EM710 multibeams were successfully calibrated and verified for use with both the loaner Seapath MRU and the new POS MV. Angular offsets were small except for the roll bias for both the EM710 and EM302. As both multibeam systems have the same large roll bias, it is likely the result of a shift in the mounting angle of the MRU. Both SIS acquisition systems have been updated with the new calibration results.

Falkor Spring 2014 Quality Assessment Report

The transducer impedances are similar to baseline measurements in 2012 and with those taken in 2013. Transducer conditions, based on these tests, are acceptable and there is no sign of degradation of the transducer arrays.

Noise levels for the EM710 remain unchanged and very low. Noise levels for the EM302 have increased at higher speeds though they remain low when the ship is stationary in the water, suggesting that the increase is associated with flow noise and/or the propulsion system.

NOAA Ship Rainier 2013 Multibeam System Review

Sensor geometry reconfiguration was successfully completed and tested on Rainier and a 14 ms orientation time delay was applied in SIS to accommodate an observed latency in the transmission of motion data from the POSMV to SIS. We feel that these two modifications will improve the data quality with the geometry reconfiguration allowing for successful application of TrueHeave in postcprocessing and the time-delay configuration improving the data quality of soundings as corrected in real-time by SIS.

Falkor 2013 Multibeam Echosounder System Review

The transducer impedances are similar to baseline measurements with exception of the EM710 transducer impedances. This latter potential issue is being examined with the manufacturer but we do not feel, after consultation with the manufacturer, that there is any cause for concern. Noise levels have not changed significantly since the 2012 trials in “Science” mode. Review of the noise results by Tim Gates indicates that there are some modules reporting higher noise levels compared to measurements taken by Gates in early 2012 and may warrant a closer investigation

Falkor 2012 Multibeam Echosounder System Review

RV Falkor is equipped with Kongsberg Maritime (KM) EM302 and EM710 multibeam echosounders (MBES). Both systems underwent Sea Acceptance Trials (SATs) in May 2012 in Sognefjord, Norway. The bathymetric and topographic constraints imposed by the fjord limited the ability to fully test the EM302. Additional system testing was conducted during a second set of trials while in transit from Newcastle-upon-Tyne, UK to Nuuk, Greenland in July 2012.

Thompson 2010 Sea Acceptance Report


A sea acceptance trial (SAT) was conducted to evaluate the performance of the EM302 multibeam echosounder (MBES) onboard the R/V Thomas G. Thompson in October 2010 off the coast of Washington state. Excellent sea conditions permitted continuous acquisition with all planned survey sites being successfully mapped. It is the intent of this report to document the results of the SAT and to provide recommendations on further improvements that can be made to maximize the performance and accuracy of the system for both bathymetric and acoustic backscatter measurements.

Langseth 2011 Acoustic Test Report

R/V MARCUS G. LANGSETH’s acoustic signature was successfully measured during this acoustic test. The levels of the EM 122 were controlled by propeller cavitation. The quietest vessel condition/speed was when the controllable pitch propellers were set to 85 percent pitch with an engine speed of 600 RPM. This yielded a ship speed of 10 knots and a sonar level of 52 dB. The seismic system created high levels when it was operating.

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