• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.179-186
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• 2015

This paper proposes the target path detection algorithm using statistical characteristics of an activated time lag along a moving path of target from a neighboring sensor in PDR(Pulse Doppler Radar) sensor node environment based on USN(Ubiquitous Sensor Network) with a limitation detecting only an existence of moving target. In the proposed algorithm, detection and non-detection time lag obtained from the experimental data are used. The experimental data are through repetitive action of each 500 times about three path scenarios such as passing in between two sensors, moving parallel to two sensors, and turning through two sensors. From this experiments, error detection percentages of three path scenarios are 5.67%, 5.83%, and 7.17%, respectively. They show that the proposed algorithm can exactly detect a target path using the limited PDR sensor nodes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.977-984
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• 2000

Atmospheric boundary layer over equatorial maritime continent was analyzed with Doppler radar. An L-band (1357.5 MHz) boundary layer radar (BLR) has been in continuous successful operation in Selpong, Indonesia(6.45, 106.7E), since November 1992. The performance of the BLR with respect to the observation height range and the wind measurement reliability has been examined on the basis of simultaneous meteorological observations. In the dry season (10-12 October 1993), we have found two types of strong echo structures appearing systematically in the equatorial planetary boundary layer with diurnal variations on clear days. The first type is the striking appearance of a strong echo layer ascending from below 300 m (in the morning) to above 3-5 km (in the afternoon), which is identified with a diurnal variation of the top of the mixing planetary boundary layer. As expected, it is higher in the Indonesian equatorial region than in midlatitudes. Another type is a layered echo appearing at 2-3 km heights from nighttime to morning, which seem to be coincident with humidity gaps. In the rainy season (20-21 February 1994), the height of the atmospheric mining was lower than that in the dry season.

• Journal of Navigation and Port Research
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• v.45 no.4
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• pp.204-211
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• 2021

The Maritime Domain Awareness system is a component that is necessary to enhance the awareness of all situations occurring at sea in relation to security, safety, economy, and the environment. To establish a marine situation recognition system that is currently being introduced in major maritime countries after approval by the International Maritime Organization's Maritime Safety Committee in 2010, operational measures should be established. For the purpose of establishing a technological foundation for the efficient construction of a Korean maritime situation recognition system, this study analyzed the status of each system (RADAR, VHF, and V-PASS, etc.) and proposed the application of data and communication standards.

• Korean Journal of Remote Sensing
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• v.40 no.3
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• pp.285-293
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• 2024

This study explores the use of Sentinel-1 Synthetic Aperture Radar (SAR), processed through Google Earth Engine (GEE), to monitor changes in the areas of Antarctic ice shelves. Focusing on the Campbell Glacier Tongue (CGT) and Drygalski Ice Tongue (DIT),the research utilizes GEE's cloud computing capabilities to handle and analyze large datasets. The study employs Otsu's method for image binarization to distinguish ice shelves from the ocean and mitigates detection errors by averaging monthly images and extracting main regions. Results indicate that the CGT area decreased by approximately 26% from January 2016 to January 2024, primarily due to calving events,while DIT showed a slight increase overall,with notable reduction in recent years. Validation against Sentinel-2 optical images demonstrates high accuracy,underscoring the effectiveness of SAR and GEE for continuous, long-term monitoring of Antarctic ice shelves.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.3
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• pp.155-164
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• 2023

About 75% of vessel collision accidents are caused by human error, which causes enormous economic loss, environmental pollution, and human casualties, thus research on automatic collision avoidance of vessels is being actively conducted. In addition, vessels must comply with the COLREGs rules stipulated by IMO when performing collision avoidance with other vessels in motion. In this study, the collision risk was calculated by estimating the position and velocity of other vessels through the Probabilistic Data Association Filter (PDAF) algorithm based on RADAR sensor data. When a collision risk is detected, we propose an event-triggered Nonlinear Model Predict Control (NMPC) algorithm that geometrically creates waypoints that satisfy COLREGs and follows them. To verify the proposed algorithm, simulations through MATLAB are performed.

• Proceedings of KOSOMES biannual meeting
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• 2004.11a
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• pp.43-47
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• 2004

Two different sensors (here, KOMPSAT and RADARSAT) are considered for ship detection, and are used to delineate the detection performance for their data The experiments are set for coastal regions of Mokpo Port and Ulsan Port and field experiments on board pilot boat are conducted to collect in situ ship validation information such as ship type and length This paper introduce mainly the experiment result of ship detection by both RADARSAT SAR imagery and land-based RADAR data, operated by the local Authority of South Korean, so called vessel traffic system (VTS) radar. Fine imagery of Ulsan Port was acquired on June 19, 2004 and in-situ data such as wind speed and direction, taking pictures of ships and natural features were obtained aboard a pilot ship. North winds, with a maximum speed of 3.1 m/s were recorded Ship's position, size and shape and natural features of breakwaters, oil pipeline and alongside ship were compared using SAR and VTS. It is shown that KOMPSAT/EOC has a good performance in the detection of a moving ship at a speed of kts or more an hour that ship and its wake can be imaged. The detection capability of RADARSAT doesn't matter how fast ship is running and depends on a ship itself, e.g. its material, length and type. Our results indicate that SAR can be applicable to automated ship detection for a VTS and SAR combination service.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1245-1255
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• 2022

Terra Nova Bay polynya (TNBP) is a representative coastal polynya in East Antarctica, which is formed by strong katabatic winds. As the TNBP is one of the major sea ice factory in East Antarctica and has a great impact on regional ocean circulation and surrounding marine ecosystem, it is very important to analyze its area change and development characteristics. In this study, we detected the TNBP from synthetic aperture radar (SAR) and optical images obtained from April 2007 to April 2022 by visually analyzing the stripes caused by the Langmuir circulation effect and the boundary between the polynya and surrounding sea ice. Then, we analyzed the area change and development characteristics of the TNBP. The TNBP occurred frequently but in a small size during the Antarctic winter (April-July) when strong katabatic winds blow, whereas it developed in a large size in March and November when sea ice thickness is thin. The 12-hour mean wind speed before the satellite observations showed a correlation coefficient of 0.577 with the TNBP area. This represents that wind has a significant effect on the formation of TNBP, and that other environmental factors might also affect its development process. The direction of TNBP expansion was predominantly determined by the wind direction and was partially influenced by the local ocean current. The results of this study suggest that the influences of environmental factors related to wind, sea ice, ocean, and atmosphere should be analyzed in combination to identify the development characteristics of TNBP.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.42 no.2
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• pp.97-103
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• 2006

The integrated navigation system(INS) for fishing boat which organized the marine radar, global positioning system(GPS) compass, automatic identification system(AIS), echo sounder, GPS and electronic nautical chart(ENC) was manufactured to reduce the marine accidents of fishing boats occurred frequently at coastal and offshore. The application possibility of INS for fishing boat was examined for basic experiments in the sea. Integration display of various information, such as other vessel's behavior, depth, own vessel's position etc. was done to help the operate user who understood the circumstance around own boat. Therefore, the system will be utilized as a useful equipment for safety voyage and fishing work on the fishing ground.

• Proceedings of the KSRS Conference
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• v.2
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• pp.938-941
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• 2006

Satellite synthetic aperture radar (SAR) images from 1995 to 2001 and field measurements of sea surface wind, sea state, and vertical stratification are used for statistical analyses of internal wave (IW) occurrence and SAR imaging conditions in the northern South China Sea (NSCS). Latitudinal distribution of IW packets shows that 22% of IW packets distributed in the east of $118^{\circ}E$ and 78% of IW packets in the west of $118^{\circ}E$. The yearly distribution of IW occurrence frequencies reveals an interannual variability. The monthly SAR-observed IW occurrence frequencies show that the high frequencies are distributed from April to July and reach a peak in June. The low occurrence frequencies are distributed in winter from December to February of next year. These statistical features are explained by solitary wave dynamics.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.1
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• pp.7-15
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• 2016

Ocean wave parameters are important for safety and efficiency of operation and routing of marine traffic. In this paper, by using X-band marine radar, we try to develop an effective algorithm for collecting ocean surface information such as current velocity, wave parameters. Specifically, by exploiting iterative refinement flow instead of using fixed control schemes, an effective algorithm is designed in such a way that it can not only compute efficiently the optimized current velocity but also introduce new cost function in an optimized way. Experimental results show that the proposed algorithm is very effective in retrieving the wave information compared to the conventional algorithms.