• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.454-456
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• 2000

다른 여느 분야의 소프트웨어 개발 분야보다도 형상관리의 필요성의 나타나는 분야로 위성탑재 소프트웨어 분야를 꼽을 수 있는데 이는 위성소프트웨어의 기본적인 특성에 기인한다고 볼 수 있다. 위성 탑재 소프트웨어는 여느 소프트웨어보다도 그 신뢰성을 중시하고 있으며 이러한 신뢰성은 개발 과정상의 잘 정의되어진 형상관리에 있다. 본 논문에서는 아리랑 위성 탑재 소프트웨어 개발에 과정에서의 형상관리 방법 및 절차를 기술하였으며 이러한 형상관리하에 아리랑 위성 탑재 소프트웨어는 개발되고 위성에 탑재되어 그 임무를 훌륭히 수행하고 있다. 이 논문을 통해서 고도의 신뢰성을 요구하는 소프트웨어 개발에 있어서의 형상관리 방법에 도움이 되고자 한다.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.99-99
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• 2003

우리나라 최초의 실용급 지구관측위성인 아리랑 1호는 지난 2003년 2월 21일부로 목표로 하였던 임무운영기간 3년을 완수하였다. 아리랑 1호의 정상 임무운영에 사용되는 탑재체는 전장광학카메라, 해양관측카메라, 그리고 우주과학 탑재체이며, 2001년 8월 원인을 알 수 없는 과전류 발생으로 임무가 중단된 우주과학 탑재체를 .제외한 나머지 탑재체들은 임무 운영기간동안 정상적으로 운영되었다. 전자광학카메라는 한반도를 비롯한 전 세계를 대상으로 지리정보를 위한 영상자료를 획득하는 것이 목적이었으며, 해양관측카메라는 생물학적 해양지도 및 해양환경 관측을 위한 자료를 획득하는 것이다. 우주과학 탑재체는 고에너지 전하입자에 의한 Single Event Upset현상, 우주방사능 관측, 그리고 전자의 온도 및 밀도 측정이 주요 목표였다. 당초 목표했던 임무운영기간을 초과한 현재(2003년 7월 1일 기준)까지 우주과학 탑재체를 제외한 나머지 탑재체들은 정상적으로 운영되고 있다. 본 논문은 아리랑 1호 발사 후 약 3년 6개월간의 기간동안 수행된 탑재체 운영결과들을 정리하였다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.1
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• pp.1-7
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• 2003

Practical use is increasing on the aerial ortho image recently, and much researches for geographic information system build that use high resolution satellite image cause this are progressing. Also many researches that use KOMPSAT-1 satellite image of resolution 6.6m are performing in these days, estimation for between aerial photo and satellite image is needed. In this treatise scanned image of aerial photo, using aerial photo resampling image of resolution equal with KOMPSAT-1 image using aerial photo, and KOMPSAT-1 satellite image use for experimental image making each orthoimage, classified feature for estimate. We evaluated to what level that an separation item could be able to estimate in each orthoimage. As result of estimation analysis, In the classified feature in aerial photo orthoimage with aerial photo resampling image orthoimage is about 61%, KOMPSAT-1 satellite image orthoimage is almost 41% could estimated. Through this investigation estimate, KOMPSAT-1 satellite sue to map updating, geographic information og non-approach area and environment inspect.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.4
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• pp.156-166
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• 2014

As of 2014, KARI (Korea Aerospace Research Institute) operates two high-resolution satellites such as Kompsat-2 and Kompsat-3. Kompsat-3 has capability of in-track stereo images acquisition but it is quite limited because the stereo mode lowers the spatial coverage in a trajectory. In this paper we analyze the epipolar geometry from the heterogeneous Kompsat-2 and Kompsat-3 image combination to epipolar resample them for 3D spatial data acquisition. The analysis was carried out using the piecewise approach with RPCs (Rational Polynomial Coefficients) and the result showed the parabolic epipolar curve pattern. We also concluded that the third order polynomial transformation is required for epipolar image resampling. The resampled image pair showed 1 pixel level of y-parallax and can be used for 3D display and digitizing.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.11
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• pp.1144-1151
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• 2010

The increasing number of orbital debris objects is a risk for satellites because of past 50 years space activities. The LEO (low earth orbit) where KOMPSAT-2 and KOMPSAT-5 are operated is including about 84% of the total space debris. Thus, the space missions need to consider the space debris. In this paper, we analysis the orbit characteristics and spatial density of space debris about KOMPSAT-2 that is in activity and KOMPSAT-5 that will be launched in 2010. Analyzed probability damage and collision with space debris are also performed. ESA MASTER2005 and of NASA DAS2.0 are used to analysis KOMPSAT mission environment. As a result, it is noted that KOMPSAT-2's collision probability was far more than KOMPSAT-5 because KOMPSAT-2's orbit has high density composed space debris.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.6_1
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• pp.455-461
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• 2013

Kompsat-3 is an optical high-resolution earth observation satellite launched in May 2012. The AEISS sensor of the Korean satellite provides 0.7m panchromatic and 2.8m multi-spectral images with 16.8km swath width from the sun-synchronous near-circular orbit of 685km altitude. Kompsat-3 is more advanced than Kompsat-2 and the improvements include better agility such as in-track stereo acquisition capability. This study investigated the characteristic of the epipolar curves of in-track Kompsat-3 stereo images. To this end we used the RPCs(Rational Polynomial Coefficients) to derive the epipolar curves over the entire image area and found out that the third order polynomial equation is required to model the curves. In addition, we could observe two different groups of curve patterns due to the dual CCDs of AEISS sensor. From the experiment we concluded that the third order polynomial-based RPCs update is required to minimize the sample direction image distortion. Finally we carried out the experiment on the epipolar resampling and the result showed the third order polynomial image transformation produced less than 0.7 pixels level of y-parallax.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.574-576
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• 1998

아리랑 위성은 자세, 전력, 열 제어 및 지상 명령 수신, 측정 데이터 수집 그리고 탑재체 지원을 위해서 3개의 80CI86 프로세서를 사용하고 있다. 단일 프로세서가 아니 여러 프로세서가 존재하게 되면 상호 간의 메시지 전달을 위해 통신 채널이 요구된다. 프로세서간의 상호 통신을 위해서 직접 연결을 사용하기도 하지만 아리랑 위성은 모듈화 개념 및 향후 확장을 위해서 MIL-STD-1553B 표준 버스 방식을 채택하고 있다. 메시지는 지상 명령 전송 및 측정 데이터 수집을 포함하므로 원활한 통신이 이루어지지 않을 경우, 위성 시스템에 심각한 문제를 발생킨다. 일반적으로 위성설계는 안정성과 신뢰성을 추구하므로 통신 설계는 다중 프로세서가 존재하는 위성의 경우 매우 중요한 의미를 지닌다. 본 논문에서는 아리랑 위성 MIL-STD-1553B 데이터 버스의 버퍼링(Buffering) 설계와 메시지의 적절한 배치를 통한 Timed-Scheduling설계 개념을 설명한다.

• Journal of Astronomy and Space Sciences
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• v.18 no.2
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• pp.153-162
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• 2001

In this paper, space radiation environment and total ionizing dose(TID) effect have been analyzed for the KOMPSAT-2 operational orbit. It has been revealed that the trapped protons are concentrated in the SAA(South Atlantic Anomaly) area and that the trapped protons and electrons, and solar protons are main factors affecting TID. It turned out that low energy Particles can be effectively blocked by aluminum shielding thickness, but high energy Particles can not be effectively blocked by increasing aluminum shielding thickness. KOMPSAT-2 total radiation dose which is accumulated continuously to spacecraft electronics has been expressed as the function of aluminum thickness. These values ran be used as the criteria for the selection of electronic parts and shielding thinkness of the KOMPSAT-2 structure or electronic box.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.10
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• pp.921-932
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• 2016

In this paper, a modified FSA(Frequency Scaling Algorithm) is proposed for KOMPSAT-5 high-resolution SAR image generation. In order to enhance performance of azimuth compression, degraded in sub-aperture processing due to the imperfect geometric parameter of data acquisition, the full-aperture signal processing algorithm is designed based on the exact time-frequency analysis. In addition, an azimuth scaling function is newly devised to make the full-aperture processing algorithm suitable for KOMPSAT-5 sliding-spotlight mode. Different from the previous sub-aperture FSA schemes, the suggested technique could accommodate the merit of unified signal processing structure regardless of operational modes of KOMPSAT-5. Through the point target simulation, it is verified that the suggested algorithm provides superior performance of azimuth compression over the existing full-aperture processing methods. The experimental results using real data acquired by KOMPSAT-5 are also given to demonstrate the effectiveness of our scheme as well.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.1
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• pp.78-85
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• 2012

Space debris is the collection of objects in orbit around the Earth that were created by humans but no longer serve any useful purpose. Since the beginning of spacecraft launch in 1957, the number of space debris has been increasing. According to USSTRATCOM, the number of space debris which were bigger than 10 cm is more than 15,000. Recently there were two critical events: One is that China shot down their satellite using missile and the other is that two satellite, United States's Iridium 33 and Russia's Cosmos 2251, collided with each other. Thanks to these events, Space environment in which KOMPSAT-2 operates has become severer. This paper presents the analysis of the number of space debris which are close to KOMPSAT-2 and the maximum conjunction probability via minimum range. Especially, this paper makes it possible to continuously monitor the space debris that is possible to hit KOMPSAT-2 through the identification and analysis.