Sea Technology

JUN 2016

The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community

Issue link: http://sea-technology.epubxp.com/i/692292

Contents of this Issue

Navigation

Page 29 of 72

www.sea-technology.com June 2016 / st 29 T o marine archaeologists, ancient wrecks offer a boun- ty of information from a certain time period. Because of the lack of natural light and low visibility underwater, traditional optical imaging has limitations for underwa- ter exploration. Acoustic imaging can investigate turbid regions and collect relevant information better than tra- ditional imaging, with divers needed to confrm the value of cultural relics. However, divers cannot know their reference position amid turbidity. When the tide comes and goes, rushing currents affect the safety of divers, so it is necessary that these moving targets are accurately and effectively tracked in real time for navigation safety. Underwater monitoring systems are widely applied to research in oceans, lakes, rivers and other waters. Be- cause a sonar system can image in poor visibility, turbid water, it is widely used in marine mapping and marine mineral resource exploration. An underwater multisensor support system enables in- teractive tasks between divers and an operating platform command center. Military Wreck In August 2015, we explored a shipwreck that is close to the East Sea of the Yangtze River estuary, where the water is turbid with poor visibility. The wreck is of a military boat sunk in the early part of the 20th century. The goal was to confrm the wreck in August, which offered suitable weather offshore. First, we examined historical records and accounts from local fshermen to determine the approximate location of the wreck, then we used unmanned sweeping survey boats with side scan sonar for a large-scale search to determine the general orientation of the wreck, then we used multi- beam sonar to scan the wreck area carefully. To understand the general shape of the wreck, we obtained a hydroacous- tic fgure of the area, and two divers were sent to identify details. Sensor Platform We placed a multisensory platform on the water surface, with the following sensors: a Trimble AgGPS 542 GNSS re- ceiver, Kongsberg Mesotech Ltd. (KML) imaging and profl- ing header sonar, LinkQuestTrackLink 1500 high-accuracy Multisensor Diver Tracking And Localization Underwater Monitoring System for Wreck Exploration By Hengli Liu • Dr. Yi Yang • Dr. Jun Luo A diver performs an underwater exploration task.

Articles in this issue

Links on this page

Archives of this issue

view archives of Sea Technology - JUN 2016
loading...
Sea Technology