10/13/2017 — admin
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. This report describes the procedures and results of the sea acceptance trial during cruise AR01-03 (February 10-17, 2016) off Charleston, South Carolina, including the following major activities:
- After review of the shipyard survey performed in Charleston, a full geometric calibration and verification routine was performed for each echosounder using the primary motion sensor.
- Self-reference surfaces were collected to evaluate the relative across track depth accuracy of each system for single-pass survey lines under typical survey modes.
- Active and passive receiver noise measurements were collected for both systems with the vessel operating under a variety of speeds and headings relative to the prevailing swell to evaluate the platform noise environment.
- Transmitter and receiver element impedance measurements were collected for both systems to establish a baseline for identifying early warning signs for any possible transducer degradation.
- Swath coverage as a function of depth was examined for both echosounders using data collected from the continental shelf to the abyssal plain.
- SSP Manager was installed to simplify XBT processing for application in SIS.
- The position feed to the EM122 and EM710 was switched from initial C-NAV feed to the tightly-coupled POS MV position/attitude solution.
In several operations, the effect of prevailing swell, strong winds, and associated bubble sweep resulted in severely degraded data quality. The initial sailing date was delayed 48 hours due to elevated sea state, and at-sea operations were adjusted on-the-fly to accommodate the conditions and collect the most useful data for characterizing the new systems under the circumstances.