• Korean Journal of Remote Sensing
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• v.39 no.6_1
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• pp.1389-1399
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• 2023

KOMPSAT-3/3A (K3/K3A) absolute radiometric calibration study was conducted based on a Field Line of sight Automated Radiance Exposure (FLARE) system. FLARE is a system, which has been developed by Labsphere, Inc. adopted a SPecular Array Radiometric Calibration (SPARC) concept. The FLARE utilizes a specular mirror target resulting in a simplified radiometric calibration method by minimizing other sources of diffusive radiative energies. Several targeted measurements of K3/3A satellites over a FLARE site were acquired during a field campaign period (July 5-15, 2021). Due to bad weather situations, only two observations of K3 were identified as effective samples and they were employed for the study. Absolute radiometric calibration coefficients were computed using combined information from the FLARE and K3 satellite measurements. Comparison between the two FLARE measurements (taken on 7/7 and 7/13) showed very consistent results (less than 1% difference between them except the NIR channel). When additional data sets of K3/K3A taken on Aug 2021 were also analyzed and compared with gain coefficients from the metadata which are used by current K3/K3A, It showed a large discrepancy. It is assumed that more studies are needed to verify usefulness of the FLARE system for the K3/3A absolute radiometric calibration.

• 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.

• 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.

• 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.

• 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.

• Korean Journal of Remote Sensing
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• v.27 no.1
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• pp.1-7
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• 2011

Satellite imagery information have not been fully utilized due to the low R&D investment in remote sensing application though Korea had succeeded in developing series of earth observing satellites during the last decades. However, another series of earth observing satellites such as KOMPSAT 3, 3-A, 5 are going to be launched in the near future. And recent global warming issues stimulate both private and public sectors to make the most of satellite imagery information. Therefore, it is inevitable to promote the utilization of Korean satellite imagery information. In this study, we analyzed the demand and restrictions in exploitation of satellite imagery information in Korea through the online survey and interview. The results showed that the standardization of pre-processing, service of detailed technical information, fast and reliable image data delivery system are mostly required.

• 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.