The R/V Neil Armstrong is a new vessel operated by Woods Hole Oceanographic Institute (WHOI) equipped with Kongsberg Maritime (KM) EM122 (12 kHz) and EM710 (70-100 kHz) multibeam echosounders. The hardware installation, calibration, software configuration, and performance of these systems were evaluated during a sea acceptance trial involving WHOI, KM, Multibeam Advisory Committee (MAC), and NOAA Office of Coast Survey personnel.
Executive Summary
The R/V Sikuliaq is equipped with Kongsberg Maritime (KM) EM302 (30 kHz) and EM710 (70-100 kHz) multibeam echosounders and a Seapath 320 positioning and attitude system with C-NAV DGNSS auxiliary input. These systems were reviewed by the Multibeam Advisory Committee (MAC) and personnel from NOAA, the University of Alaska Fairbanks (UAF), and Kongsberg Maritime (KM) during sea acceptance trials (SAT) in August 2014.
Executive Summary
Executive Summary
A Kongsberg EM710 multibeam echosounder was installed on the NOAA Ship Fairweather by Bay Ship and Yacht Co. of Alameda, CA in December, 2014. This mapping sonar replaced a Reson 8160 and a Reson 7111.
The performance of the EM710 was evaluated during sea‐trials from 9 February to 13 February, 2015. The performance of this system as installed and integrated meets the manufacturer specification and is adequate to meet the intended charting mission. All modes of operation were tested between 50 and 500 meters.
Gates Acoustic Services was tasked by University of Alaska, Fairbanks, to investigate and quantify acoustic issues associated with operation of the R/V SIKULIAQ. An at-sea investigation was accomplished during ship operations in deep water out of San Juan, Puerto Rico on September 12-18, 2014.
The multibeam systems and attendant sensors on R/V Sikuliaq were successfully evaluated. The installation and integration of the systems is compliant with current best-practices and there are no major deficiencies that should hinder anticipated missions. Installation parameters and configurations of the systems have been verified and all patch-tests have been completed and loaded to the systems. As configured at the end of the SAT cruise and as detailed in this report, the systems are ready for generalized mapping activities including bathymetry, seafloor backscatter, and water-column work.
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.
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.
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.