The Comparative Analysis Of Multi-Beam Sounding System, Side-Scan Sonar And Magnetometer In The Wreck Detection

"The projects of the navigational obstruction detection in Zhejiang and Fujian coastal area" as the basis in this paper, wreck detection work commenced looking for possible existing navigational obstruction on the map, thereby improving the utilization of the shipping lanes to ensure safe navigation. The project is a mandatory task, which requires accuracy and speed of wreck detection. Combined with the specific requirements of the project and the actual situation of the survey area, a set of high efficiency integrated detection method was designed, and its applied research has been conducted.In the field of bathymetry, multi-beam sounding system proved its superiority with wide coverage and high efficiency, is commonly used in hydrographic and oceanographic survey. Using multi-beam sounding system to detect seafloor target, cases of seabed can’t be reflected visually real-time, a digital terrain model should be built at first, then the terrain images should be built based on DTM to reflect subtle changes caused by slope and aspect in topography. Multi-beam sounding system uses 3D visualization method to determine target, and measures its position and height directly in 3D GIS system, the shape features of object can be viewed from different angles too.Side-scan sonar is a common tools in underwater targets(such as shipwrecks, mines, pipelines, etc.) detection, which is characterized by high-resolution, real-time continuous display of acoustic images. The quality and the general scale of target could be quickly determined while surveying at sea. In all kinds of emergency sweep survey and target detection work, side-scan sonar has played an important role.Marine magnetometer has good detection sensitivity when detecting ferromagnetic object only, for ensuring the safety of the instrument and keeping magnetometer detector as close to the target as possible, survey ship must regulate speed to control the depth of towing detector, so that the weather conditions during survey and the ship type selection has been limited, which makes detecting seabed targets by magnetometer with certain limitations. Marine magnetometer was usually working with side-scan sonar, multi-beam sounding systems simultaneously, in order to achieve the best detection results in practical projects.In this paper, the engineering practical applications of multi-beam systems, side-scan sonar and marine magnetometer for detecting shipwrecks were compared and analyzed, the advantages and disadvantages of three kinds of detection method were summarized. Practice has proved that: the advantage of multi-beam sounding system is the high positioning accuracy, however, its detecting efficiency is lower than the side-scan sonar due to the restrictions of depth and beam angle. Marine magnetometer is often used as a means to verify the conclusion, not the top priority probing tools in the wreck detection. Multi-beam sounding system, side-scan sonar and marine magnetometer have a good complementary and the determination accuracy could be improved by using these instruments together in wreck detection.