• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.349-352
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• 2007

The Fourth Assessment Report of IPCC predicted that global warming is already happening and it should be caused from the increase of greenhouse gases by the extension of human activities. These global changes will give a serious influence for human society. Global environment can be monitored by the earth observation using satellite. For the observation of global climate change and resolving the global warming process, satellite should be useful equipment and its detecting data contribute to social benefits effectively. JAXA (former NASDA) has made a new plan of the Global Change Observation Mission (GCOM) for monitoring of global environmental change. SGLI (Second Generation GLI) onboard GCOM-C (Climate) satellite, which is one of this mission, provides an optical sensor from Near-DV to TIR. Characteristic specifications of SGLI are as follows; 1) 250 m resolutions over land and area along the shore, 2) Three directional polarization observation (red and NIR), and 3) 500 m resolutions temperature over land and area along shore. These characteristics are useful in many fields of social benefits. For example, multi-angular observation and 250 m high frequency observation give new knowledge in monitoring of land vegetation. It is expected that land products with land aerosol information by polarization observation are improved remarkably. We are studying these possibilities by ground data and satellite data.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2004년도 대한지구물리학회.한국지구물리탐사학회 공동학술대회 초록집
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• pp.3-17
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• 2004

Space-borne Earth observation technique is one of the most cost effective and rapidly advancing Earth science research tools today and the potential field and micro-wave radar applications have been leading the discipline. The traditional optical imaging systems including the well known Landsat, NOAA - AVHRR, SPOT, and IKONOS have steadily improved spatial imaging resolution but increasing cloud covers have the major deterrent. The new Earth observation satellites ENVISAT (launched on March 1 2002, specifically for Earth environment observation), ALOS (planned for launching in 2004 - 2005 period and ALOS stands for Advanced Land Observation Satellite), and RADARSAT-II (planned for launching in 2005) all have synthetic aperture radar (SAR) onboard, which all have partial or fully polarimetric imaging capabilities. These new types of polarimetric imaging radars with repeat orbit interferometric capabilities are opening up completely new possibilities in Earth system science research, in addition to the radar altimeter and scatterometer. The main advantage of a SAR system is the all weather imaging capability without Sun light and the newly developed interferometric capabilities, utilizing the phase information in SAR data further extends the observation capabilities of directional surface covers and neotectonic surface displacements. In addition, if one can utilize the newly available multiple frequency polarimetric information, the new generation of space-borne SAR systems is the future research tool for Earth observation and global environmental change monitoring. The potential field strength decreases as a function of the inverse square of the distance between the source and the observation point and geophysicists have traditionally been reluctant to make the potential field observation from any space-borne platforms. However, there have recently been a number of potential field missions such as ASTRID-2, Orsted, CHAMP, GRACE, GOCE. Of course these satellite sensors are most effective for low spatial resolution applications. For similar objects, AMPERE and NPOESS are being planned by the United States and France. The Earth science disciplines which utilize space-borne platforms most are the astronomy and atmospheric science. However in this talk we will focus our discussion on the solid Earth and physical oceanographic applications. The geodynamic applications actively being investigated from various space-borne platforms geological mapping, earthquake and volcano .elated tectonic deformation, generation of p.ecise digital elevation model (DEM), development of multi-temporal differential cross-track SAR interferometry, sea surface wind measurement, tidal flat geomorphology, sea surface wave dynamics, internal waves and high latitude cryogenics including sea ice problems.

• 한국광학회지
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• 제11권1호
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• pp.6-12
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• 2000

위성에 탑재된 지구관측용 카메라는, 지상의 망원경과 같은 원리로, 우주상공에서 지표면 관측을 자동적으로 수행하고 관측정보를 지상으로 전달해 주는 장치다. 이용 목적에 따라 카메라의 해상도 또는 분해능, 관측대역, 관측폭, 위성의 궤도 등의 규격이 결정된다. 고해상도는 카메라 관련 제반 기술 및 경험이 부족한 국내의 여건에 적합한 소형 위성용 고해상도 카메라의 규격을 제시하며 이에 따른 광학 설계와 제작, 조립 및 측정오차를 제시한다.

• 대한임베디드공학회논문지
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• 제13권5호
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• pp.253-259
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• 2018

Recently, small satellite industries are rapidly changing. Demand for high performance small satellites is increasing with the expansion of Earth Observation Satellite market. A next-generation small satellites require a higher resolution image storage capacity than before. However, there is a problem that the HW configuration of the existing small satellite image storage device could not meet these requirements. The conventional data storing system uses SDRAM to store image data taken from satellites. When SDRAM is used in small satellite platform of a next generation, there is a problem that the cost of physical space is eight times higher and satellite price is two times higher than NAND Flash. Using the same satellite hardware configuration for next-generation satellites will increase the satellite volume to meet hardware requirements. Additional cost is required for structural design, environmental testing, and satellite launch due to increasing volume. Therefore, in order to construct a low-cost, high-efficiency system. This paper shows a next-generation solid state recorder unit (SSRU) using MRAM and NAND Flash instead of SDRAM. As a result of this research, next generation small satellite retain a storage size and weight and improves the data storage space by 15 times and the storage speed by 4.5 times compare to conventional design. Also reduced energy consumption by 96% compared to SDRAM based storage devices.

• Journal of Astronomy and Space Sciences
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• 제29권4호
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• pp.407-411
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• 2012

Space-borne remote sensing is an effective and inexpensive way to identify crop fields and detect the crop condition. We examined the multi-temporal spectral characteristics of rice fields in South Korea to detect their phenological development and condition. These rice fields are compact, small-scale parcels of land. For the analysis, moderate resolution imaging spectroradiometer (MODIS) and RapidEye images acquired in 2011 were used. The annual spectral tendencies of different crop types could be detected using MODIS data because of its high temporal resolution, despite its relatively low spatial resolution. A comparison between MODIS and RapidEye showed that the spectral characteristics changed with the spatial resolution. The vegetation index (VI) derived from MODIS revealed more moderate values among different land-cover types than the index derived from RapidEye. Additionally, an analysis of various VIs using RapidEye satellite data showed that the VI adopting the red edge band reflected crop conditions better than the traditionally used normalized difference VI.

• 대한원격탐사학회지
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• 제26권6호
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• pp.653-664
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• 2010

The land surface reflectance is a key parameter influencing the climate near the surface. Therefore, it must be determined with sufficient accuracy for climate change research. In particular, the characteristics of the bidirectional reflectance distribution function (BRDF) when using earth observation system (EOS) are important for normalizing the reflected solar radiation from the earth's surface. Also, wide swath satellites like SPOT/VGT (VEGETATION) permit sufficient angular sampling, but high resolution satellites are impossible to obtain sufficient angular sampling over a pixel during short period because of their narrow swath scanning. This gives a difficulty to BRDF model based reflectance normalization of high resolution satellites. The principal objective of the study is to add BRDF modeling of high resolution satellites and to supply insufficient angular sampling through identifying BRDF components from SPOT/VGT. This study is performed as the preliminary data for apply to high-resolution satellite. The study provides surface parameters by eliminating BRD effect when calculated biophysical index of plant by BRDF model. We use semi-empirical BRDF model to identify the BRD components. This study uses SPOT/VGT satellite data acquired in the S1 (daily) data. Modeled reflectance values show a good agreement with measured reflectance values from SPOT satellite. This study analyzes BRD effect components by using the NDVI(Normalized Difference Vegetation Index) and the angle components such as solar zenith angle, satellite zenith angle and relative azimuth angle. Geometric scattering kernel mainly depends on the azimuth angle variation and volumetric scattering kernel is less dependent on the azimuth angle variation. Also, forest from land cover shows the wider distribution of value than cropland, overall tendency is similar. Forest shows relatively larger value of geometric term ($K_1{\cdot}f_1$) than cropland, When performed comparison between cropland and forest. Angle and NDVI value are closely related.

• 대한원격탐사학회지
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• 제38권6_4호
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• pp.1911-1923
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• 2022

The availability of high-resolution satellite images provides precise information without direct observation of the research target. Korea Multi-Purpose Satellite (KOMPSAT), also known as the Arirang satellite, has been developed and utilized for earth observation. The machine learning model was continuously proven as a good classifier in classifying remotely sensed images. This study aimed to compare the performance of the support vector machine (SVM) model in classifying the land cover of the Delaware River port area on high and medium-resolution images. Three optical images, which are KOMPSAT-2, KOMPSAT-3A, and Sentinel-2B, were classified into six land cover classes, including water, road, vegetation, building, vacant, and shadow. The KOMPSAT images are provided by Korea Aerospace Research Institute (KARI), and the Sentinel-2B image was provided by the European Space Agency (ESA). The training samples were manually digitized for each land cover class and considered the reference image. The predicted images were compared to the actual data to obtain the accuracy assessment using a confusion matrix analysis. In addition, the time-consuming training and classifying were recorded to evaluate the model performance. The results showed that the KOMPSAT-3A image has the highest overall accuracy and followed by KOMPSAT-2 and Sentinel-2B results. On the contrary, the model took a long time to classify the higher-resolution image compared to the lower resolution. For that reason, we can conclude that the SVM model performed better in the higher resolution image with the consequence of the longer time-consuming training and classifying data. Thus, this finding might provide consideration for related researchers when selecting satellite imagery for effective and accurate image classification.

• 대한공간정보학회지
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• 제20권1호
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• pp.117-123
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• 2012

세계 각국은 우주개발에 대한 많은 관심으로 인하여 자국의 지구관측위성을 발사하고 있다. 이로 인해 고해상도 위성영상은 날로 증가하고 있다. 또한 웹 환경의 발달로 인하여 일반 사용자는 위성영상을 쉽게 접하고 있다. 본 연구에서는 위성영상의 활용성을 높이고자 위성의 센서모델링에 대한 해박한 지식이 다소 없더라도 쉽게 3차원 좌표를 획득할 수 있도록 웹 기반 위성사진측량에 대한 기초연구를 수행하였다. 웹 환경에서 고해상도 위성영상을 이용하여 3차원 좌표를 결정하기 위한 여러 요소기술을 분석하고 IKONOS 위성영상을 이용하여 사례연구를 수행하였다. 센서모델링 방법중의 하나인 평행투영모델을 적용하여 에피폴라 영상을 생성하고 웹 환경에서 3차원 위치를 결정할 수 있는 프로토타입 형태의 프로그램을 구현하였다. 이를 통해 일반 사용자도 쉽게 웹 환경에서 3차원 위치를 결정할 수 있었고 기 구축된 공간정보의 갱신과 서비스 분야에 활용될 수 있음을 알았다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.162-164
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• 2003

The multi-disciplinary research project Strengthening Local Authorities in Risk Management (SLARIM), initiated by ITC, includes three case study cities in Asia. An important question is: what are the essential data for risk management and how to access such data. The role of common sources (e.g. census data), data derived from remote sensing (high-resolution satellite imagery, aerial photos), and data from close sensing (field observation, including mobile GIS) to acquire essential risk management data will be discussed. Special attention is given to the question of the minimum area and to disaggregating population data. A few examples are given of Kathmandu / Lalitpur, Nepal.

• 한국항공우주학회지
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• 제33권8호
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• pp.99-104
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• 2005

인공위성에서 구조체의 역할은 발사환경 및 궤도상의 모든 발생 가능한 환경에서 위성체를 안전하게 지지하는 것이다. 인공위성의 개발단계에서 구조 및 열 개발모델은 유한요소모델 보정 및 구조강도/특성 확인 등의 구조적인 특징과 열평형시험을 통한 열적 안정성의 확인을 그 목적으로 한다. 이때 얻어진 결과는 실제 비행모델의 개발 시 구조 및 열적 안정성 검증 등의 중요한 자료로써 활용된다. 본 논문에서는 고정밀 지구관측위성의 구조 및 열 개발모델에 대해 구조 관점에서의 설계/해석에 대해 기술하고 또한 모달 시험을 통한 시험결과와 유한요소해석과의 비교에 대해 기술한다.