Seabed mapping using multibeam sonar and combining with former bathymetric data

Download

index.pdf

Date

2015

Author

Gürtürk, Fatih Furkan

Metadata

Show full item record

Item Usage Stats

141
views

78
downloads

The most practical methods in underwater mapping are based on acoustic measurements. In this thesis, a simulation program was developed for mapping the sea depth with a multibeam echosounder. The factors affecting the mapping resolution and accuracy were shown on the simulation. The correction of the sound velocity profile, which affects the sonar’s performance, with the Ray Theory was explained. The error sources were explained for measured depth values on each beam and the position assigned for depth measurements. In transfer of the achieved data to earth reference frame, ship movement and ship’s position by GPS were added to the simulation with a certain error rate. In the next phase, use of previously taken bathymetric data on improvement of new measurement is conducted using a novel method. With the use of old measurements, an optimization algorithm is applied to minimize errors caused by ship movement and position assignment. With correction of ship movement data the position errors are corrected and this approach is applied in order to improve the old map data by weighting with measurement quality. In the conclusion part, simulation results were compared with the acceptable error quantity stated by the International Hydrography Organization (IHO). On specified depth measurements, error amounts are given and error amount related with ship motion data was summarized. Improvement achieved by weighting of corrected new data and previous data with their measurement quality was shown. Error results were compared on the previous map, on the new measurement and on the map after the improvement. Echosounder resolution required in a bathymetry study in accordance with the IHO standards, ship movement sensor precision, and GPS positioning precision are obtained. Data achieved after improvement were compared with the acceptable error quantity stated by the IHO standards.

Subject Keywords

Underwater acoustics., Ocean tomography., Multibeam mapping., Bathymetric maps.

URI

http://etd.lib.metu.edu.tr/upload/12619572/index.pdf
https://hdl.handle.net/11511/25308

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Underwater channel modeling for sonar applications Epçaçan, Erdal; Çiloğlu, Tolga; Department of Electrical and Electronics Engineering (2011) Underwater acoustic channel models have been studied in the context of communication and sonar applications. Acoustic propagation channel in an underwater environment exhibits multipath, time-variability and Doppler e ects. In this thesis, multipath fading channel models, underwater physical properties and sound propagation characteristics are studied. An underwater channel model for sonar applications is proposed. In the proposed model, the physical characteristics of underwater environment are considered ...
Sea surface motion induced effects on high frequency underwater acoustic signals / Güneş, Hasan; Çiloğlu, Tolga; Department of Electrical and Electronics Engineering (2014) Acoustic signal scattering from the moving sea surface constitutes one of the most significant problems in underwater communication and sonar applications when dealing with signal processing especially at high frequencies. In this thesis, a realistic 3D linear sea surface wave model which solves governing equations is combined with a ray based computationally efficient acoustic model, BELLHOP, in order to simulate the effects of the time-evolving sea surface on acoustic waves. Rough sea surface realizations...
Topology Control Vector Based Forwarding Algorithm for Underwater Acoustic Networks Yazgi, Ilkay; Baykal, Buyurman (2016-05-19) The communication range of underwater acoustic networks (UAN) is limited by the properties of underwater environment. Especially, the networks including small number of nodes have communication problems for long ranges. To challenge this problem, topology control in UAN is a promising solution. In this study, Topology Control Vector Based Forwarding Algorithm (TC-VBF) is proposed. The TC-VBF uses nodes' position to determine the forwarding vector. In this work, the TC-VBF is evaluated comparatively with alt...
Topology control vector based forwarding algorithm for underwater acoustic networks Yazgı, İlkay; Baykal, Buyurman; Department of Electrical and Electronics Engineering (2015) The communication range of underwater acoustic sensor networks (UASN) is limited by the underwater environment. Acoustic networks with huge number of sensors may have long communication range with appropriate protocols in literature. On the other hand, especially, the networks including small number of nodes have communication problems for long ranges. To challenge this problem, topology control in underwater acoustic networks is a promising solution. In this study, a novel approach, Topology Control Vector...
Near-field scanning in the time domain on a spherical surface - A formulation using the free-space Green's function Koc, S; Aydın Çivi, Hatice Özlem; Buyukdura, OM (2001-10-01) Two formulations for determining the characteristics of an unknown source of acoustic waves using the measurement of its field at its near zone are presented. The measurement in both cases is to be performed on a spherical scan surface which encapsulates the source. The first is for an ideal probe which measures the field at its location. The knowledge of the field is sufficient; its normal derivative is not required. In the second formulation a realistic probe is considered. This time it is required only t...

Citation Formats

F. F. Gürtürk, “Seabed mapping using multibeam sonar and combining with former bathymetric data,” M.S. - Master of Science, Middle East Technical University, 2015.