Page 61: of Marine Technology Magazine (March 2014)

Instrumentation: Measurement, Process & Analysis

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tinuing to collect multibeam data. High-Interest Targets For high resolution point cloud data collection, an R2Sonic 2024 Ultra High Resolution (UHR) mulitibeam sonar was used. With the ultra-high resolution sonar system, the crew collected high- resolution point cloud data for about 20 historic assets of particular interest. As a further effort in providing the most accurate point cloud data possible, GNSS phase data and inertial data were collected and logged with an Applanix POS MV motion reference unit. Data were then post processed with Appla- nix?s POSPac MMS software providing a ?true heave? blended GNSS / inertial solution. The post processed data  les were then read into a hydrographic survey software package. Martin de Kievit, business development manager for Trimble Marine in the Heavy Civil Construction division, explains that the survey software grabs input from the GNSS receiver where it allows for dis- play and editing of track lines, sound-ing pro les and text data. The software system correlates time-tagged tide, ves- sel position, motion and sound velocity correction data which are used to accu-rately plot and record locations.?Our surveys reported some 300 targets [artifacts] and about 20 ?new? wreckage sites were more fully devel- oped,? said Nash. As submerged targets of interest were more fully developed and accurately located, crews also launched small manned submarines to capture  lm footage of various high-pro le wreck- age sites. Led by Andy Sherrell of Sher- rell Ocean Services, the crew  lmed sites in order to capture color and de-tails of what the servicemen may have faced on that fateful June day. Using video, sonar, 3D imagery and 3D visu- alizations, the crew is essentially ?peel- ing back the water to bring these stories to life,? Nash added. With higher resolution images and precise point cloud data, the crew is hoping to determine the actual ship, aircraft or vehicle name of the artifacts revealed. With this information, histori- ans will also endeavor to derive names, ranks and associations of the crewmem- bers that were aboard the vessels or vehicles when they were sunk and de- stroyed. Updating the GIS Database During the months to come, teams will continue to work with the mas- sive 11TB data set. The United King- dom Hydrographic Of ce (UKHO) and the French nautical charting authority (SHOM) are collaborating in an effort to update the international wreck data-base for the area. Because a large per- centage of these identi ed artifacts are newly discovered or were inaccurately positioned previously, the team is work- ing to make these corrections before they deliver the complete survey data to the UNESCO World Heritage Com- mittee for review. To commemorate the event, MC4 and LCL Production are producing a 90-minute documentary for the international market. PBS/Nova will broadcast an adaptation in North Amer- ica, both to be aired memorializing the 70th anniversary. Honoring Those Who Were There on ?The Longest Day? During the of cial 70th Anniversary D-Day ceremony scheduled for June 2014, veterans, dignitaries and archeol- ogists will meet along this historic coast to honor those who have served and sac- ri ced. Led by the French Department of Underwater Archeological Research, manned submarines will also escort a handful of WWII veterans and histori- ans underwater to investigate a few of the high-pro le identi ed wrecks. ?Nearly everyone we approached about providing support for this his- toric mapping expedition, by means of donating equipment or personnel, was extremely supportive and enthusiastic about the project,? said Nash. ?Every- one has considered it an honor to be in-volved in this effort, and I know I feel that way, as do our guys.? MTR #2 (50-65).indd 61MTR #2 (50-65).indd 612/21/2014 3:51:13 PM2/21/2014 3:51:13 PM

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