• Korean Journal of Remote Sensing
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• v.30 no.4
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• pp.431-444
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• 2014

As applications of spaceborne SAR imagery are extended, there are increased demands for accurate registrations for better understanding and fusion of radar images. It becomes common to adopt multi-resolution SAR images to apply for wide area reconnaissance. Geometric correction of the SAR images can be performed by using satellite orbit and attitude information. However, the inherent errors of the SAR sensor's attitude and ground geographical data tend to cause geometric errors in the produced SAR image. These errors should be corrected when the SAR images are applied for multi-temporal analysis, change detection applications and image fusion with other sensor images. The undesirable ground registration errors can be corrected with respect to the true ground control points in order to produce complete SAR products. Speeded Up Robust Feature (SURF) technique is an efficient algorithm to extract ground control points from images but is considered to be inappropriate to apply to SAR images due to high speckle noises. In this paper, an attempt is made to apply SURF algorithm to SAR images for image registration and fusion. Matched points are extracted with respect to the varying parameters of Hessian and SURF matching thresholds, and the performance is analyzed by measuring the imaging matching accuracies. A number of performance measures concerning image registration are suggested to validate the use of SURF for spaceborne SAR images. Various simulations methodologies are suggested the validate the use of SURF for the geometric correction and image registrations and it is shown that a good choice of input parameters to the SURF algorithm should be made to apply for the spaceborne SAR images of moderate resolutions.

• Journal of Satellite, Information and Communications
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• v.12 no.4
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• pp.78-86
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• 2017

Japan has a lot of interest about weapons systems development of surrounding national and has invested heavily in securing intelligence assets to get information about them, because of conflict issues between Japan and Russia with four northern islands, China with Senkaku Islands and entry policy into the Pacific. Japan has used a large budget to detect and intercept ballistic missile for reasons of the launch of the Taepodong missile in 1998. After took over SIGINT equipments which U.S. force had operated in 1950s~1960s, Japan made a technological analysis and advanced IT technology to produce superior equipments. Japan's SDF has installed them in 19 locations across Japan. In addition, Japan's JASDF has installed advanced early warning RADAR to detect aircraft and high speed ballistic missile entering JADIZ with S-band in 28 locations across Japan. It is possible to detect missile launch preparations, engine tests, and launch moments at any time for operation of 6 satellites high resolution reconnaissance system and 6 aegis ships. In close cooperation with the US, Japan is accessible to the SBIRS networks which detects the launch of a ballistic missile in neighboring countries. In the future, Because the United States wants Japan to act as part of the United States in East, south Asia, it is believed that the exchange of intelligence on the surrounding countries between two countries will be enhanced.

• Korean Journal of Remote Sensing
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• v.39 no.6_3
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• pp.1731-1745
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• 2023

Within the framework of the post-2020 climate regime, the Paris Agreement's emphasis on Nationally Determined Contributions and Biennial Transparency Reporting is paramount in addressing its long-term temperature goal. A salient issue is the treatment of wetland ecosystems within the context of Land Use, Land-Use Change, and Forestry, as defined by the Intergovernmental Panel on Climate Change. In the 2019 National Inventory Report, wetlands were recategorized as emission sources due to their designation as inundated areas. This study employs C-band radar imagery to discriminate between inundated and non-inundated regions of wetlands, enabling the quantification of their spatial dynamics. The research capitalizes on 24-period Sentinel-1 satellite data to cover both the inundation and desiccation phases while centering its attention on Ungok Wetland, a Ramsar-designated inland wetland conservation area in Korea. The inundated area is quantitatively assessed through the integration of multi-temporal Sentinel-1 Single-Look Complex (SLC) data, aerial orthophotography, and inland wetland spatial information. Furthermore, the study scrutinizes fluctuations in the maximum and minimum inundated areas, with substantial changes corroborated via drone aerial reconnaissance. The outcomes of this investigation hold the potential to make substantive contributions to the refinement of national greenhouse gas absorption and emission factors, thereby informing the development of comprehensive greenhouse gas inventories. These efforts align directly with the overarching objectives of the Paris Agreement.

• The Korean Journal of Air & Space Law and Policy
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• v.29 no.1
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• pp.97-126
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• 2014

October 4, 1957 the Soviet Sputnik 1 was launched into space the first time in the history of mankind. After launching, the realm of humankind was expanded to space. Today all countries of the world wage a fierce competition in order to utilize space for various purposes. World powers of space such as United States, Russia, China, and Japan, put reconnaissance satellites and ocean surveillance satellites into orbit, being able to easily see equipment and troops movement on earth. Each country makes efforts to occupy space assets through the militarization of space and expand national interests. Recently private companies or individuals involved in commercial space activities are becoming more prevalent. Thus, in addition to space activities for military purposes, commercial space activities become widespread. Individuals and private companies as well as nations are also involved in space activities. Outer space is not the monopoly of space powers such as the United States and Russia. The whole human race can benefit from free access to space, being the common heritage of mankind. In particular, outer space becomes an indispensable element of military activities and human life. Many countries are now entering space development, putting a lot of budget into new development programs. Republic of Korea also built the Narodo Space Center, starting its space development with budget and manpower. We have to find out ways to use space not only for military purposes but also for commercial space activities that can contribute to the national economy. In addition, through the joint efforts of the international community, we have to make efforts for preservation and peaceful use of space. Various issues relating to space activities and research should be studies in order to contribute to the progress of humanity. Those issues include the definition of outer space, space debris reduction and environmental conservation issues, non-bind measure cooperation - European International Code of Conduct, space law and national legislation related empowerment issues, arms control measures in space, and restrictions on the use of nuclear fuel. We also need to be involved in the discussion of those issues as one of responsible space countries. In addition, we try to find out regional cooperation schemes such as the ESA in the Europe actively. Currently in the Northeast Asia, cooperation bodies led by Japan and China respectively, are operated in the confrontational way. To avoid such confrontation, a new cooperative body needs to be established for cooperation on space exploration and information. The system to allow the exchange of satellite information for early warning of natural disasters needs to be built as well. In addition, efforts to enhance the effectiveness of the relevant international treaties on space, and fill in the blanks in international space laws should be made at the same time. To this end, we have to do a leading role in the establishment of standards such as non-binding measures (resolution) - Code of Conduct, being discussed in the UN and other organizations, and compliance with those standards. Courses in aerospace should be requires in law schools and educational institutes, and professional manpower need to be nurtured. In addition, the space-related technology and policy needs to be jointly studied among the private, public, and military groups, and the cross exchange among them should be encouraged.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.12
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• pp.1846-1854
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• 2022

The sophistication and diversification of mission equipment for surveillance and reconnaissance is leading to a demand for large-capacity public data links. Overseas, a T4 class(274Mbps) common data link was applied to the Global hwak, a high-altitude unmanned aerial vehicle, and various research and development are being conducted in Korea. In this paper, we propose a structure in which pilot is additionally applied to improve SNR performance while minimizing data transmission rate loss in the DVB-S2 frame structure, which is a european satellite broadcasting standard, for high-capacity transmission of T4 class or higher in the common data link. For the performance evaluation of the proposed structure, the performance of the DVB-S2 was compared and analyzed by simulating the UAV data link channel environment. As a result of simulation, 0.15% of transmission rate loss occurred at T4 class transmission rate compared to DVB-S2 in the proposed structure, but improved SNR reception performance of 0.2~0.3dB was confirmed in the UAV channel environment.