• Satellite Communications and Space Industry
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• v.3 no.1
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• pp.16-19
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• 1995

• Satellite Communications and Space Industry
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• v.6 no.2 s.14
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• pp.73-83
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• 1998

• Satellite Communications and Space Industry
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• v.2 no.3
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• pp.27-35
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• 1994

• Satellite Communications and Space Industry
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• v.6 no.2 s.14
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• pp.4-5
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• 1998

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.547-549
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• 2003

위성의 개발 및 제작에는 많은 비용과 기간이 소요되며. 일반적으로 사용되는 장비들과는 전혀 다른 우주환경에서 임무를 수행하게 된다. 그리고 위성의 경우에는 발사이후에 발생하는 오류들을 수정하는 것이 거의 불가능하므로 위성의 성공적인 임무완수를 위해서는 철저한 사전검증 작업들이 필요하게 된다. 특히, 위성의 궤도, 자세를 제어하고 실제적인 임무수행을 관할하는 위성탑재소프트웨어에 대한 완벽한 검증이 필요하다. 이러한 소프트웨어의 통합 및 조립시험. 검증시험을 위해 저궤도 위성의 FSW(Flight Software) 개발단계에서 실제 위성시스템과 유사한 인터페이스를 제공하는 개발도구인 STB(Software Test Bed)가 제작되며, 제작된 STB를 통한 FSW의 검증시험 및 분석을 지원하기 위한 구문분석프로그램으로 VTSP(Verification Test Script Parser)를 개발하게 된다. 본 논문에서는 이러한 STB와 VTSP에 대한 전반적인 소개와 함께 개발된 STB와 VTSP를 이용하여 실제 위성탑재소프트웨어를 검증하기 위한 시험환경에 대해 알아보고자 한다.

• Journal of Astronomy and Space Sciences
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• v.23 no.3
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• pp.259-268
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• 2006

The use of GPS receiver at outer space becomes common in low earth orbit. Recently most of satellites use GPS receiver as navigation solution for finding satellite position. However, the accuracy of navigation solution acquiring directly from GPS receiver is not enough in satellite application such as map generation. Post-processing concepts such as Precise Orbit Determination (POD) are recently applied to satellite data processing to improve satellite position accuracy. The POD uses raw measurement data instead of navigation solution of GPS receiver. The performance of raw measurement data depends on raw measurement data accuracy and tracking loop algorithm of GPS receiver. In this paper, a method for evaluating performance of raw measurement data is suggested. Test environment and procedure of the low earth orbit satellite acquiring for navigation solution of GPS receiver and navigation solution of POD are described. In addition, accuracy on navigation solution of GPS receiver, raw measurement data, and navigation solution of POD are analyzed. The proposed method can be applicable to general low earth orbit satellite.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.7
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• pp.709-716
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• 2009

Thermal condition according to the operation attitude of a satellite in orbit would be essential to be known because the orbit attitude is a dominant factor to affect satellite thermal design. In this paper, the change in space thermal environment and the thermal effect in thermal design are studied for a low earth orbit satellite according to the yaw motion. The present satellite retains sun-pointing attitude during daylight due to the fixed type solar arrays. And it also moves along the orbit with constant yaw motion in a longitudinal axis so that a star tracker which is a star sensor for satellite's attitude control always looks into the deep space. This attitude is considered in its better visibility to the stars for a successful mission operation. Also, it is required to access the corresponding thermal effects due to the yaw motion. Therefore, we try to verify these by the thermal analysis for the satellite thermal model with the yaw motion.

• Journal of Internet Computing and Services
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• v.21 no.6
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• pp.1-12
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• 2020

Low-Orbit satellite mobile networks can provide services through miniaturized terminals with low transmission power, which can be used as reliable means of communication in the national public disaster network and defense sector. However, the high traffic environment in the emergency preparedness situation increases the new call blocking probability and the handover failure probability of the satellite network, and the increase of the handover failure probability affects the QoS because low orbit satellites move in orbit at a very high speed. Among the channel allocation methods of satellite communication, the FCA shows relatively better performance in a high traffic environment than DCA and is suitable for emergency preparedness situations, but in order to optimize QoS when traffic increases, the new call blocking and the handover failure must be minimized. In this paper, we propose LEO-DBC (LEO satellite dynamic beam width control) technique, which improves QoS by adaptive adjustment of beam width of low-orbit satellites and call time of terminals by improving FCA-QH method. Through the LEO-DBC technique, it is expected that the QoS of the mobile satellite communication network can be optimally maintained in high traffic environments in emergency preparedness situations.

• Journal of Satellite, Information and Communications
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• v.12 no.3
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• pp.93-97
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• 2017

In satellites, even a small error in flight software could cause a failure of missions. Therefore, there are strict development and verification processes for a high reliability of flight software. However, satellites on orbits could meet unexpected situations including hardware malfunction. In this case, it is necessary for flight software to be updated to cope with the unexpected situations and to continue their missions. This paper reviews reprogramming capability of next generation LEO satellites.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.167-168
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• 2008

인공위성에서 궤도 변경에 사용되는 추진계를 제외한 인공위성 본체와 탑재체의 모든 기능은 전기에너지를 이용하여 임무를 수행한다. 이러한 전기에너지가 태양전지 배열기에 의해 생성되는 만큼, 태양전지 배열기의 설계는 인공위성 개발에서 매우 중요하다. 인공위성을 위한 태양전지 배열기는 발사시의 충격과 우주환경에서의 방사능에 대한 노출을 직접적으로 받으므로 견고하게 제작되어야 하며, 인공위성의 수명 말기까지 위성 운용을 위한 충분한 전력을 생산하도록 설계되어야 한다. 본 논문에서는 저궤도 인공위성을 위한 태양전지 배열기의 제작 및 설계에 관하여 기술한다.