engleski

Analysis of State-of-the-Art Hydrographic Survey Technologies

Bathymetry data is critical for safety of navigation and is used for many other applications. The world’s oceans cover 71% of the Earth, but we still have mapped less than 20 % of the world’s oceans and 50 % of the total global continental shelf area (shelf depth is shallower than 200 m) was unsurveyed or inadequate surveyed according to IHO S-44 standards. Continental shelves make up about 8% of the entire area covered by oceans and seas and the remaining parts have a poorly defined sea bottom. Therefore, it is necessary to find efficient and preferably coast effective methods of bathymetry determination. Determination bathymetry or measurement of underwater topography is very challenging and demanding task. Therefore efforts are being made to find new techniques which will successfully solve this task, besides performing traditional survey by using big and expensive hydrographic research vessels. The decision goes in two directions solving: airborne/spaceborne and in situ measurement techniques. Today three types of airborne/spaceborne shallow waters bathymetric measurement techniques are most commonly used: LiDAR or laser scanner technique, Satellite Derived Bathymetry technique (multispectral imagery) or its sub-variant Airborne Derived Bathymetry (ADB), and SAR technique (Synthetic aperture radar - SAR imagery). There are also two in situ techniques which have started to be used in the last few years: Unmanned autonomous vehicle (UAV) and Underwater drone or Remotely Operated Vehicles (ROV). The paper briefly describes each of these “non-traditional” data collection techniques as new and innovative technologies that can increase the efficiency of collecting bathymetric data. The description include all advantages and disadvantages of individual techniques, the achieved measurements accuracy and ranges of the sea depths. Finally, it was concluded that SDB and LiDAR methods are suitable for bathymetric survey of shallow coastal areas, SAR method is used to determine the offshore depth ranging between about 10 and 100 m, while ASVs, USVs, AUVs, and UUVs are appropriate for a variety of offshore and coastal hydrographic surveys.

hydrography ; airborne/spaceborne techniques ; in situ techniques

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