• Journal of Ocean Engineering and Technology
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• v.34 no.5
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• pp.351-360
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• 2020

Of late, demand for test sites for marine equipment such as ASV, AUV, ROV, and various underwater sensors is increasing. The authors have focused on an oscillating water column (OWC), which is being constructed near Chagwido Island Jeju, as one of the test-sites. The main objective of the OWC is to produce wave energy and develop technologies. It has been built in the sea approximately 1 km off the coast. It has berth accommodation and some rooms that can be used as laboratories. To investigate the feasibility of its usage as a test site for marine equipment, we acquired bathymetric data around the OWC by using a multi-beam echo sounder and a single-beam scanning sonar. The accessibility of the OWC from nearby ports and the use of support vessels or ships were also investigated. 3D point cloud data from the multi-beam echo sounder and 2D acoustic images from the scanning sonar are expected to be used as references for identifying changes over time. In addition, through these experiments, we derived a procedure to use this facility as a test site by using the IDEF0 functional modelling method. Based on this preliminary investigation and previously reported examples, we determined the general conditions and preferences for evaluating the performance of various marine equipment heuristically. Finally, we developed five applications that were derived from this investigation.

• Korean Journal of Remote Sensing
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• v.11 no.3
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• pp.129-145
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• 1995

SeaBeam2000, a multibeam echo sounder, is a new generation seabed mapping system of which a single swath covers an angular range of -60.deg. to 60.deg. from the vertical direction with 121 beams. It provides high-density and high-quality bathymetric data along with sidescan acoustic data. The purpose of the research is to develop a system for processing multibeam underwater acoustic and bathymetric data using digital signal processing techniques. Recently obtained multibeam echo sounder data covering a survey area in the East Sea of Korea ($37{\circ}$.00'N to $37{\circ}$30'N and $129{\circ}$40'E to $130{\circ}$30'E) are preliminarily processed using the developed system and reproduced in the raster image format as well as three dimensionally visualized form.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.3
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• pp.273-281
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• 2002

Determination of sediment type is generally based on ground truthing. This method, however, provides information only for the limited sites. Recent developments of remote classification of seafloor sediments made it possible to obtain continuous profiles of sediment types. QTC View system, which is an acoustic instrument providing digital real-time seabed classification, was used to classify seafloor sediment types in the Suyoung Bay, Pusan. QTC View was connected to 50 kHz echo sounder, All parameters of QTC View and echo sounder are uniformly kept during survey. By ground truthing, the sediments are classified into seven types, such as slightly gravelly sand, slightly gravelly sandy mud, gravelly muddy sand, clayey sand, sandy mud, slightly gravelly muddy sand, and rocky bottom. By the first remote classification using QTC View, four sediment types are clearly identified, such as slightly gravelly sand, gravelly mud, slightly gravelly muddy sand, and rocky bottom. These are similar to the result of the second survey. Also the result of remote classification matches well with that of ground truthing, but for sediment type determined by minor component. Therefore, QTC View can effectively be used for remote classification of seafloor sediments.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.4
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• pp.28-39
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• 2014

Several studies have been performed globally on the construction of integrated systems that are available for the integrated use of 3D geographic information on terrain and oceans. Research on 3D geographic modeling is also facilitated by the application of Lidar surveying, which enables the highly accurate realization of 3D geographic information for a wide area of land. In addition, a few marine research organizations have been conducting investigations and surveying diverse ocean information for building and applying MGIS(Marine Geographic Information System). However, the construction of integrated geographic information systems for both terrain and oceans has certain limitations resulting from the inconsistency in reference systems and datum levels between two data. Therefore, in this investigation, integrated geospatial information has been realized by using a combined topographical map, after matching the reference systems and datum levels by integration of airborne Lidar data and multi-beam echo sounder data. To verify the accuracy of the integrated geospatial information data, ten randomly selected samples from study areas were selected and analyzed. The results show that the 10 analyzed data samples have an RMSE of 0.46m, which meets the IHO standard(0.5m) for depth accuracy of hydrographic surveys.

• Korean Journal of Remote Sensing
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• v.33 no.3
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• pp.313-324
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• 2017

A lava tube is one of the hot issues of lunar science because it is regarded as a good candidate place for setting a lunar base. Recently much effort has been made to find lunar lava tubes. However, preceding works mainly made use of high-resolution lunar surface image data in conjunction with geomorphological consideration to present some lava tube candidates. Yet, those candidates stay no more than indirect indications. We propose a new data analysis technique of High Frequency (HF) radar observation data to find lunar lava tubes of which location depth is smaller than the range resolution of the radar pulse. Such shallow target echoes cannot be resolved from surface echoes, which presents the different location of the lunar surface compared to that of real lunar surface. The proposed technique instead finds the surface range (distance from LRS to the reflector of the most intense signal) anomaly which occurs as a result of the low range resolution of LRS pulse. We applied this technique to the surface range of Kaguya Lunar Radar Sounder (LRS) data. The surface range was deduced to make LRS surface elevation which was compared with the average surface elevation of Kaguya Digital Terrain Model (DTM). An anomalous discrepancy of the surface elevation was found in the Rima Galilaei area, which suggests the existence of a shallow lava tube.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.3
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• pp.295-301
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• 2008

Bathymetric data collected using a multi-beam echo sounder during marine scientific survey is essential for geologic and oceanographic research works. Accurate measurment of sound velocity profile(SVP) in water-column is important for bathymetric data processing. SVP can vary at different locations during the survey undertaken for wide areas. In addition, an observational error can occur when different equipments(Sound Velocity Profiler, Conductivity Temperature Depth, eXpendable BathyThermograph) are used for measuring SVP at the same water column. In this study, we used an MB-system software to show changes in bathymetry caused by variation of SVP. The analyses showed that the sound velocity(SV) changes due to the depth and thickness of thermocline had more significant effects on the resulting bathymetric data than those of surface mixed layer. The observational errors between SVP measuring instruments did not cause much differneces in the processed bathymetric data. Bathymetric survey line is better to be established to the direction that the change of temperature can be minimize to reduce the variation of SVP during the data acquisition along the survey line.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.06a
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• pp.236-236
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• 2011

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.65-65
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• 2008

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• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2005.11a
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• pp.3-6
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• 2005

• Ocean and Polar Research
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• v.28 no.4
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• pp.467-473
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• 2006

The EM 120, a newly installed multibeam echo sounder on RM Onnuri, has several advantages over the previously installed SeaBeam 2000 in performance and thus data quality. The EM 120 system provides a bottom topographic map with high resolution by (1) increasing the number of beams, (2) increasing the across track swath range, (3) measuring the more accurate sound velocity within the water column, and (4) improving stabilization for pitching, rolling, and yawing of the ship. This study compares EM 120 and SeaBeam 2000 echo sounders in terms of the data quality from the same survey area in the Clarion-Clipperton Zone, NE Pacific. Our result shows that the EM 120 provides more precise topographic data than the SeaBeam 2000. Although overall trends of data, such as topographic direction and relief, are similar for both echo sounders, the water depths measured by the EM 120 are shallower than that of SeaBeam 2000 by 80 to 90 meters.