Improving shallow-water multibeam target detection at low grazing angles

Pereira, Doulgas Luiz da Silva

Repositório Institucional da Produção Científica da Marinha do Brasil (RI-MB)

Use este identificador para citar ou linkar para este item: https://hdl.handle.net/20.500.14867/848289

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Campo DC	Valor	Idioma
dc.contributor.advisor	Clarke, J. E. Hughes	-
dc.contributor.author	Pereira, Doulgas Luiz da Silva	-
dc.date.accessioned	2026-03-27T12:20:58Z	-
dc.date.available	2026-03-27T12:20:58Z	-
dc.date.issued	2015	-
dc.identifier.citation	PEREIRA, Douglas Luiz da Silva. Improving shallow-water multibeam target detection at low grazing angles. 2015. 111 f. Dissertação (Master of Science in Engineering) – Department of Geodesy and Geomatics Engineering, University of New Brunswick, Fredericton, 2015.	pt_BR
dc.identifier.uri	https://hdl.handle.net/20.500.14867/848289	-
dc.description	Beyond approximately 60º incidence angle, many modern multibeam echo sounders have difficulty maintaining sufficient depth accuracy and seabed target detection to comply with International Hydrographic Organization (IHO) standards. In some cases, a target at such a low grazing angle is not detected due to limitations of the existing bottom detection method and filters applied by the manufacturer. In lieu of clear positive bathymetric indicators, a data gap within the bathymetric surface or a shadow in the backscatter image may be the only indication of the presence of that target. This research presents a refined bottom detection algorithm based on the Bearing Direction Indicator (BDI) method. The BDI approach can markedly improve target detection capability at low grazing angles in shallow waters by independently discriminating each echo’s direction of arrival irrespective of the beam spacing. The algorithm can be applied in post-processing as long as the water column data is retained. Two test datasets were collected using an EM 2040D employing angular sectors as wide as +/-82°. Data were acquired over a site with multiple IHO-compliant anthropogenic objects to assess the EM 2040D ability to detect low-grazing-angle targets prior to, and after, application of the newly developed algorithm. Results obtained clearly illustrate that the BDI algorithm can enhance low-grazing-angle target detection/definition.	pt_BR
dc.language.iso	en	pt_BR
dc.publisher	Diretoria de Hidrografia e Navegação (DHN)	pt_BR
dc.rights	openAccess	pt_BR
dc.subject	Multibeam echo sounder	pt_BR
dc.subject	Low grazing angles	pt_BR
dc.subject	Shallow water	pt_BR
dc.subject	Bathymetry	pt_BR
dc.subject	Batimetria	pt_BR
dc.subject	Ecobatímetro multifeixe	pt_BR
dc.title	Improving shallow-water multibeam target detection at low grazing angles	pt_BR
dc.title.alternative	Aprimoramento da detecção de alvos por multifeixe em águas rasas a baixos ângulos rasantes	pt_BR
dc.type	doctoralThesis	pt_BR
dc.subject.dgpm	Hidrografia	pt_BR
dc.subject.setorMarinha	Diretoria-Geral de Navegação (DGN)	pt_BR
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