2020 Healy EM122 QAT Report

Multibeam System:




  • The USCGC Healy (HLY) is equipped with a Kongsberg Maritime EM122 multibeam echosounder (1° TX x 2° RX) with Seapath 330+ (primary) and Applanix POS MV (secondary) positioning / attitude systems
  • The Multibeam Advisory Committee (MAC) was asked to assist with Quality Assurance Testing (QAT) of the ship’s multibeam echosounders ahead of the 2020 field season; due to widespread travel restrictions, MAC personnel provided remote support for line planning and data analysis from shore
  • MAC communication with Healy and UCSD/STARC personnel (Lee Ellett, Brendon Mendenhall, Daniel Yang) commenced in June 2020 with planning for calibrations (‘patch tests’) for the EM122 using both position / attitude systems as the primary feeds off the coast of Washington and opportunistic testing of swath accuracy, EM hardware health, and RX noise levels over a range of speeds
  • The calibration and accuracy test plan was developed with proven calibration sites used for other vessels, including during the 2017 Healy EM122 QAT by Paul Johnson and Vicki Ferrini; detailed reports of the 2017 QAT and 2014 noise testing are available at https://mac.unols.org/category/ships/healy
  • This report describes the calibration results and implementation in SIS, as well as opportunistic system hardware health, swath coverage, and noise testing
    The granite block remains the origin for all sensor reference frames; Seapath and POS MV output are valid at
    the granite block
  • EM122, Seapath, and POS MV configurations are based on vessel surveys performed by IMTEC (2010, 2014) with updates based on tape measurements of new antenna positions (2014-17) and appropriate modifications based on calibration results
  • Healy and STARC personnel confirmed that no modifications have been made to the EM122, Seapath, and POS MV installations since the 2017 QAT, aside from a Seapath antenna upgrade (see note in this report)
  • While this report describes the most recent calibration results, the 2017 QAT report should be referenced for more details of the system geometry review (e.g., ship reference frame and survey documentation, sources for antenna offsets, etc.)
Attachment Size
HLY_2020_EM122_QAT_report_v1p1.pdf 10.55 MB