• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.12
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• pp.977-985
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• 2020

KOMPSAT-3A launched in 2015 provides Middle InfraRed(MIR) images with 3.3~5.2㎛. Though the satellite provide high resolution images for estimating bright temperature of ground objects, it is different from existing satellites developed for natural science purposes. An atmospheric compensation process is essential in order to estimate the surface brightness temperature from a single channel MIR image of KOMPSAT-3A. However, even after the atmospheric compensation process, there is a brightness temperature error due to various factors. In this paper, we analyzed the cause of the brightness temperature estimation error by tracking signal flow from camera physical characteristics to image processing. Also, we study on possibility of improvement of MIR brightness temperature bias error of KOMPSAT-3A using GEOKOMPSAT-2A. After bias compensation of a real nighttime image with a large bias error, it was confirmed that the surface brightness temperature of KOMPSAT-3A and GEOKOMPSAT-2A have correlation. We expect that the GEOKOMPSAT-2A images will be helpful to improve MIR brightness temperature bias error of KOMPSAT-3A.

• Korean Journal of Remote Sensing
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• v.35 no.6_4
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• pp.1313-1318
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• 2019

The Korea Aerospace Research Institute (KARI) has developed and operated a total of three KOMPSAT series(K-3, 3A and 5). The main purpose of satellite development is to utilize data obtained from satellites. In other words, continuous efforts should be made to improve the accuracy of data processing and expand the application areas. This special issue introduces pre-processing and application technologies based on optic and Synthetic Aperture Radar (SAR) sensors of KOMPSAT series. It is believed that more systematic research and development will be needed as follow-up KOMPSAT series and small satellites are under development.

• The Magazine of the IEIE
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• v.42 no.4
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• pp.35-43
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• 2015

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.32.6-33
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• 2010

현재 우리나라에서는 고해상도 광학관측위성인 다목적실용위성 3호(EO), 3A호(EO/IR)를 개발 중에 있으며, 이들의 개발 현황과 앞으로의 발전 방향에 대한 소개를 하고자 함. 지구표면의 정밀/광역 관측에 큰 장점을 지닌 관측위성은 많은 기술적 난관이 있으며, 이를 극복하기 위한 위성 본체 및 대구경 광학계 기술을 소개하고자 한다. 일반 천문 망원경용 광학계와의 차이점을 위주로 다목적실용위성 3호, 3A호의 위성광학계 설계의 특징과 현재 개발 중인 위성용 카메라의 조립 시험에 대한 현황을 위주로 향후 우리가 나아가야할 방향에 대한 고찰이 있을 예정이다. 또한 위성의 운영 특성과 운영 시 필요한 검보정 (Cal/Val) 과정에 대한 준비 상황도 소개하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.936-939
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• 2015

현재 우리나라의 대표적인 저궤도실용위성 시리즈인 '다목적실용위성'은 K2, K3, K5, K3A(2호, 3호, 5호, 3A호) 이렇게 총 네 가지로 구성되어 있다. 본 논문에서는 한국항공우주연구원에서 운영하는 다목적실용위성 K3인 일상 임무계획(Mission Planning)의 모듈 자동화 시스템 개발에 대한 내용을 다뤘다. 그중에서도, 일상적으로 반복 수행되는 K3 임무계획 업무 중에서 수동 작업을 자동화하기 위해 객체지향 CBD 개발 방법론을 토대로 C#을 이용한 자동화 시스템을 구조화 시키는 방안에 대해 주력하였다. 그 결과로 자동화 개념 정립을 위한 Feasibility Study를 수행할 것이다. 이를 다목적실용위성 K3 임무계획 중 일상적인 임무계획에 한하여 제한적으로 적용할 수 있을 것으로 기대하며, 이는 나아가 본 선행연구 결과물을 이용하여 K3 임무계획 자동화시스템에 적용에 적극 활용될 수 있을 것이다.

• Journal of Korea Water Resources Association
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• v.56 no.8
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• pp.497-508
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• 2023

Agricultural reservoirs are crucial structures for water resources monitoring especially in Korea where the resources are seasonally unevenly distributed. Optical and Synthetic Aperture Radar (SAR) satellites, being utilized as tools for monitoring the reservoirs, have unique limitations in that optical sensors are sensitive to weather conditions and SAR sensors are sensitive to noises and multiple scattering over dense vegetations. In this study, we tried to improve water body detection accuracy through optical-SAR data fusion, and quantitatively analyze the complementary effects. We first detected water bodies at Edong, Cheontae reservoir using the Compact Advanced Satellite 500(CAS500), Kompsat-3/3A, and Sentinel-2 derived Normalized Difference Water Index (NDWI), and SAR backscattering coefficient from Sentinel-1 by K-means clustering technique. After that, the improvements in accuracies were analyzed by applying K-means clustering to the 2-D grid space consists of NDWI and SAR. Kompsat-3/3A was found to have the best accuracy (0.98 at both reservoirs), followed by Sentinel-2(0.83 at Edong, 0.97 at Cheontae), Sentinel-1(both 0.93), and CAS500(0.69, 0.78). By applying K-means clustering to the 2-D space at Cheontae reservoir, accuracy of CAS500 was improved around 22%(resulting accuracy: 0.95) with improve in precision (85%) and degradation in recall (14%). Precision of Kompsat-3A (Sentinel-2) was improved 3%(5%), and recall was degraded 4%(7%). More precise water resources monitoring is expected to be possible with developments of high-resolution SAR satellites including CAS500-5, developments of image fusion and water body detection techniques.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.2
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• pp.113-125
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• 2012

This research is aimed at evaluating the land surface characterization of KOMPSAT-3A middle infrared (MIR) data. Airborne Hyperspectral Scanner (AHS) data, which has MIR bands with high spatial resolution, were used to assess land surface temperature (LST) retrieval and classification accuracy of MIR bands. Firstly, LST values for daytime and nighttime, which were calculated with AHS thermal infrared (TIR) bands, were compared to digital number of AHS MIR bands. The determination coefficient of AHS band 68 (center wavelength $4.64{\mu}m$) was over 0.74, and was higher than other MIR bands. Secondly, The land cover maps were generated by unsupervised classification methods using the AHS MIR bands. Each class of land cover maps for daytime, such as water, trees, green grass, roads, roofs, was distinguished well. But some classes of land cover maps for nighttime, such as trees versus green grass, roads versus roofs, were not separated. The image classification using the difference images between daytime AHS MIR bands and nighttime AHS MIR bands were conducted to enhance the discrimination ability of land surface for AHS MIR imagery. The classification accuracy of the land cover map for zone 1 and zone 2 was 67.5%, 64.3%, respectively. It was improved by 10% compared to land cover map of daytime AHS MIR bands and night AHS MIR bands. Consequently, new algorithm based on land surface characteristics is required for temperature retrieval of high resolution MIR imagery, and the difference images between daytime and nighttime was considered to enhance the ability of land surface characterization using high resolution MIR data.

• Journal of Aerospace System Engineering
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• v.13 no.2
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• pp.60-65
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• 2019

TerraSAR-X, launched in June 2007, and TanDEM-X, June 2010, are remote-sensing satellites with 1M resolution that are capable of observing the ground even during the nighttime and poor weather conditions. The two satellites had been developed under a public-private partnership between the German Aerospace Centre and Airbus in the interest of the commercial marketing for German satellite data. However, the data of high-grade earth remote-sensing system, such as those of the satellites, has been produced by a military satellite and thus used under limited circumstances in Germany. Therefore, a legislation to commercialize the German satellite data and to protect its national security is needed. For this, SatDSiG was enacted in December 2007. Thus this article will contain the main contents of SatDSiG and its implication for Korea, which stared to export data of Kompsat 3, 3A and 5 in 2018.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.10
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• pp.1001-1007
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• 2013

In the case of multi-mission LEO(Low Earth Orbit) operations, depending on the orbit of each satellite, one ground site is supposed to be communicated with more than two satellites at the same time. On top of that, image data processing system is generally mission-specific and 1:1 backup configuration. For the reason, if ground site has smaller number of antenna than that of satellite, interface with image data processing system would be very complicated. In this paper, considering that two LEO satellites can be operating and image data recording unit in redundancy can be easily plug-in, the implementation of matrix receiving structure is described. This matrix receiving structure has been validated from KOMPSAT-2 and -3(KOrea Multi-Purpose SATellite-2 and -3) since KOMPSAT-3 was launched in May, 2012. This structure will be applied for the KOMPSAT-3A and -5 through its expandability.

• Korean Journal of Remote Sensing
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• v.35 no.6_4
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• pp.1327-1339
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• 2019

Surface reflectance obtained by absolute atmospheric correction from satellite images is useful for scientific land applications and analysis ready data (ARD). For Landsat and Sentinel-2 images, many types of radiometric processing methods have been developed, and these images are supported by most commercial and open-source software. However, in the case of KOMPSAT 3/3A images, there are currently no tools or open source resources for obtaining the reflectance at the top-of-atmosphere (TOA) and top-of-canopy (TOC). In this study, the atmospheric correction module of KOMPSAT 3/3A images is newly implemented to the optical calibration algorithm supported in the Orfeo ToolBox (OTB), a remote sensing open-source tool. This module contains the sensor model and spectral response data of KOMPSAT 3A. Aerosol measurement properties, such as AERONET data, can be used to generate TOC reflectance image. Using this module, an experiment was conducted, and the reflection products for TOA and TOC with and without AERONET data were obtained. This approach can be used for building the ARD database for surface reflection by absolute atmospheric correction derived from KOMPSAT 3/3A satellite images.