in reports |

2024 R/V Revelle EM712/EM124 QAT

Cruise ID: RR2401
Multibeam System: EM712/EM124
Dates: February 12, 2024

  1. During the winter 2023-24 maintenance period, the R/V Roger Revelle (RR) underwent significant engine work and received a new Seapath 380 receiver and HMI (the MRU 5+ and antennas were not modified)
  2. The Multibeam Advisory Committee (MAC) was asked to assist with routine Quality Assurance Testing (QAT) for the ship’s multibeam echosounders; due to scheduling conflicts, the MAC provided remote support for planning and data analysis leading up to and throughout the QAT
  3. Planning followed the standard MAC SAT/QAT checklist, starting with configuration review, hardware health, and noise testing following the engine work; calibrations for both systems were carried out at proven sites near San Diego used by a variety of vessels (e.g., 2023 Sally Ride EM124 and EM712 QAT)
  4. Dockside configuration reviews indicated a rollback to outdated offsets for the EM124 (e.g., potentially by loading an older PU parameters file during software updates); all EM124 offsets were checked again and updated to post-2023 QAT results, including a TX array pitch correction that was detected after the 2020 SAT and applied during the 2023 QAT between Chile and South Africa
  5. Noise testing initially showed very high levels; this was determined to be caused by ballasting operations, and subsequent noise testing showed levels more in line with the 2020 EM124 and EM712 SAT results
  6. The MAC thanks the Revelle’s shipboard technicians for collecting all QAT data, re-running some tests to verify results (e.g., RX noise), and following up with questions to ensure data quality throughout the process
  7. EM124 and EM712 calibrations proceeded smoothly, aside from minor complications stemming (potentially) from swath stabilization during significant yaw in one of the two EM712 heading test files
  8. This report describes the procedures and results for system geometry review, geometric calibrations, hardware health monitoring, and RX noise characterization for the EM124 and EM712, with recommendations for future data collection
  9. The MAC is available to assist with planning opportunistic testing to round out routine quality assurance testing (QAT) over the field season ahead; these priorities for additional testing would include:
    a. Swath coverage data over wide depth ranges for both systems with all other acoustic systems secured
    b. Accuracy crossline testing over existing reference surfaces (e.g., see 2020 SAT report for options) or at new reference sites that can be planned in the vessel’s future working areas
    c. Follow-up with Kongsberg regarding low Z values observed for 16 channels on one EM712 RX module

Attached Documents

Report:

Revelle_2024_EM712_EM124_QAT_report_v1Download

Related Information