• ETRI Journal
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• v.30 no.1
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• pp.59-67
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• 2008

The necessity for the precise time synchronization of measurement data from multiple sensors is widely recognized in the field of global positioning system/inertial navigation system (GPS/INS) integration. Having precise time synchronization is critical for achieving high data fusion performance. The limitations and advantages of various time synchronization scenarios and existing solutions are investigated in this paper. A criterion for evaluating synchronization accuracy requirements is derived on the basis of a comparison of the Kalman filter innovation series and the platform dynamics. An innovative time synchronization solution using a counter and two latching registers is proposed. The proposed solution has been implemented with off-the-shelf components and tested. The resolution and accuracy analysis shows that the proposed solution can achieve a time synchronization accuracy of 0.1 ms if INS can provide a hard-wired timing signal. A synchronization accuracy of 2 ms was achieved when the test system was used to synchronize a low-grade micro-electromechanical inertial measurement unit (IMU), which has only an RS-232 data output interface.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.645-648
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• 2005

The COMS(Communication, Ocean and Meteorological Satellite), a multi-mission geo-stationary satellite, is being developed by KARl. The first mission of the COMS is the meteorological image and data gathering for weather forecast by using a five channel meteorological imager. The second mission is the oceanographic image and data gathering for marine environment monitoring around Korean Peninsula by using an eight channel Geostationary Ocean Color Imager(GOCI). The third mission is newly developed Ka-Band communication payload certification test in space by providing communication service in Korean Peninsula and Manjurian area. There were many low Earth orbit satellites for ocean monitoring. However, there has never been any geostationary satellite for ocean monitoring. The COMS is going to be the first satellite for ocean monitoring mission on the geo-stationary orbit. The meteorological image and data obtained by the COMS will be distributed to end users in Asia-Pacific area and it will contribute to the improved weather forecast.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.637-640
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• 2005

In the development of a electronic system for a optical payload comprising mainly EOS(Electro-Optical Sub-system) and PDTS(Payload Data Transmission Sub-system), many aspects should be investigated and discussed for the easy implementation, for th e higher reliability of operation and for the effective ness in cost, size and weight as well as for the secure interface with components of a satellite bus, etc. As important aspects the interfaces between a satellite bus and a payload, and some design features of the CEU(Camera Electronics Unit) inside the payload are described in this paper. Interfaces between a satellite bus and a payload depend considerably on whether t he payload carries the PMU(Payload Management Un it), which functions as main controller of the Payload, or not. With the PMU inside the payload, EOS and PDTS control is performed through the PMU keep ing the least interfaces of control signals and primary power lines, while the EOS and PDTS control is performed directly by the satellite bus components using relatively many control signals when no PMU exists inside the payload. For the CEU design the output channel configurations of panchromatic and multi-spectral bands including the video image data inter face between EOS and PDTS are described conceptually. The timing information control which is also important and necessary to interpret the received image data is described.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.320-323
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• 2008

This study attempts to establish a system extracting and monitoring cultural grounds of seaweeds (lavers, brown seaweeds and seaweed fulvescens) and abalone on the basis of both KOMPSAT-2 and Terrasar-X data. The study areas are located in the northwest and southwest coast of South Korea, famous for coastal cultural grounds. The northwest site is in a high tidal range area (on the average, 6.1 min Asan Bay) and has laver cultural grounds for the most. An semi-automatic detection system of laver facilities is described and assessed for spacebome optic images. On the other hand, the southwest cost is most famous for seaweeds. Aquaculture facilities, which cover extensive portions of this area, can be subdivided into three major groups: brown seaweeds, capsosiphon fulvescens and abalone farms. The study is based on interpretation of optic and SAR satellite data and a detailed image analysis procedure is described here. On May 25 and June 2, 2008 the TerraSAR-X radar satellite took some images of the area. SAR data are unique for mapping those farms. In case of abalone farms, the backscatters from surrounding dykes allows for recognition and separation of abalone ponds from all other water-covered surfaces. But identification of seaweeds such as laver, brown seaweeds and seaweed fulvescens depends on the dampening effect due to the presence of the facilities and is a complex task because objects that resemble seaweeds frequently occur, particularly in low wind or tidal conditions. Lastly, fusion of SAR and optic spatial images is tested to enhance the detection of aquaculture facilities by using the panchromatic image with spatial resolution 1 meter and the corresponding multi-spectral, with spatial resolution 4 meters and 4 spectrum bands, from KOMPSAT-2. The mapping accuracy achieved for farms will be estimated and discussed after field verification of preliminary results.

• Journal of Information Processing Systems
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• v.13 no.2
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• pp.321-339
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• 2017

In this work, we are interested in the extraction of areas of interest from satellite images by introducing a MO-TRIBES/OC-SVM approach. The One-Class Support Vector Machine (OC-SVM) is based on the estimation of a support that includes training data. It identifies areas of interest without including other classes from the scene. We propose generating optimal training data using the Multi-Objective TRIBES (MO-TRIBES) to improve the performances of the OC-SVM. The MO-TRIBES is a parameter-free optimization technique that manages the search space in tribes composed of agents. It makes different behavioral and structural adaptations to minimize the false positive and false negative rates of the OC-SVM. We have applied our proposed approach for the extraction of earthquakes and urban areas. The experimental results and comparisons with different state-of-the-art classifiers confirm the efficiency and the robustness of the proposed approach.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.3
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• pp.22-27
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• 2012

In oceanic flight routes, HF radio and satellite data links have been used for air-to-ground communication, but these systems have long propagation delay and low data throughput. In this paper, we propose a reliable system to overcome the weakness of current HF radio and satellite communication systems for oceanic aeronautical flight routes. The proposed scheme uses only one aeronautical VHF channel in multi-hop oceanic communication environments and supports a hybrid type of multiple access, which consists of random access and TDMA (Time Division Multiple Access) scheme. The proposed system improves performance on delay and throughput as an effective solution to communicate end-to-end on the oceanic flight routes and strengthens the reliability of oceanic aeronautical communication.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.1
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• pp.98-106
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• 2003

Because satellite images have the advantage of high resolution, multi-spectral, revisit and wide swath characteristics, it is increased to utilize satellite image and get information little by little in nowadays. In order to utilize remote sensed images effectively, it is necessary to process satellite images through many processing steps. Among them, geometric correction is essential step for satellite image processing. In this study, we constructed geometric correction data using LANDSAT satellite images. First, we extracted GCPs from maps and constructed database over the Korean peninsular. Second, LANDSAT satellite images, 165 scenes were corrected geometrically using GCP database. Finally, we made 7 mosaic images by means of geometric correction images over Korean peninsular. We think that constructed geometric correction data will be used for many application fields as basic data.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.145-148
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• 2007

The Korea Multi-Purpose Satellite-2 (KOMPSAT-2) was launched in July 2006 and The main mission of the KOMPSAT-2 is a high resolution imaging for the cartography of Korea peninsula by utilizing Multi Spectral Camera (MSC) images. The camera resolutions are 1 m in panchromatic scene and 4 m in multi-spectral imaging. KOMPSAT-2 measure the position, velocity and attitude data of satellite using by star sensor, gyro sensor, and GPS sensor. This paper provides an initial geometric accuracy assessment of the KOMPSAT-2 high resolution image, both geometric Cal/Val overview.

• Journal of Satellite, Information and Communications
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• v.9 no.3
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• pp.47-52
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• 2014

This paper introduces the Optical Camera Communications (OCC) using image processing technique. The architecture and operation of OCC system are given. To enhance data rate which is limited by sampling operation of commercial 30fps camera, multi colors transmission technique is employed, leading to the importance of color image processing technique. Multi color encoding and image processing based decoding will be proposed in the paper.

• Proceedings of the KSRS Conference
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• 2006.03a
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• pp.398-403
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• 2006

2008년 발사를 목표로 개발되고 있는 통신해양기상위성(COMS : Communication, Ocean and Meteorological Satellite)의 기상 탑재체를 이용한 기상 관측 임무는 기상청 기상위성센터(가칭)의 고유 임무로서, 이는 기상탑재체에서 관측한 자료를 수신 처리하여 고품질의 영상과 분석 자료를 생산하여 기상 예보 업무에 활용하고, 위성을 통하여 국내외 사용자들에게 분배하는 것 등을 포함한다. 위성을 통한 기상 자료 서비스는 국내에서는 최초로 시도되는 것으로, 국제기상위성운영 기관들의 모임인 기상위성조정그룹회의(CGMS Coordination Group for Meteorological Satellites)에서 권고하는 High Rate Information Transmission/Low Rate Information Transmission(HRIT/LRIT)라는 특정 자료 형태를 사용하여 분배하게 된다. 따라서 본 논문에서는 CGMS에서 권고하는 CCSDS (Consultative Committee for Space Data Systems) 전송 규격과 일본의 MTSAT-1R(Multi-functional Transport Satellite) 위성 사용자 서비스 자료 형태를 참고하여 통신해양기상위성의 효과적인 기상자료 분배를 위한 HRIT/LRIT 데이터 전송률을 분석하여 보았다.