Airborne LASER bathymetric data applicability to Nautical Cartography: Case study for Fernando de Noronha

• Autor(a) principal: Do Nascimento, Guilherme Antonio Gomes
• Data de Publicação: 2021
• Outros Autores: Galo, Maurício [UNESP]
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.11137/1982-3908_2021_44_37487; http://hdl.handle.net/11449/230386
• topic: Hydrographic Survey; Light Detection And Ranging (LiDAR); Vertical Uncertainty

A Hydrographic Survey (HS) has as main goal to obtain data for editing and updating nautical documents, these, focused on the safety of navigation. In order to establish a standard of uncertainty parameters for nautical charts, the International Hydrographic Organization (IHO) defines minimum levels of confidence for different orders. Depth information influences the maximum operational draft for a vessel to safely travel in a region, causing impact on port operations and limiting the commercial transactions. As a complement to the traditional survey technique conducted with a boat-coupled echosounder, there is the option of performing a HS using LiDAR (Light Detection And Ranging) technology from aircraft, through LiDAR aerial bathymetry (ALB - Airborne LASER Bathymetry) system, which can operate with LASER pulses both only in the green region of the electromagnetic spectrum, as in conjunction with pulses in near-infrared region. Considering these points, this work analyzed the differences between the information obtained by these two techniques, with an aim to evaluate the ALB’s potential of application to update nautical charts. Data were acquired in the Fernando de Noronha Archipelago in 2011, while the reference dataset was obtained in the same year by a multibeam echosounder campaign. The evaluations allowed to estimate the dynamic of the depth discrepancies between the two systems in different depths, relief and seafloor composition in the area of interest. The impossibility of mapping areas deeper than 50 m was observed, as well as those in breaking zones. However, the overlap of up to four flight strips indicated the possibility of expanding the seabed description. The sample uncertainty obtained showed an outcome that fitted the HS to order 1A, according to IHO parameters.