• Journal of Aerospace System Engineering
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• v.10 no.4
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• pp.90-97
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• 2016

GEO-KOMPSAT-2A and GEO-KOMPSAT-2B are under development by KARI to replace the COMS mission, and will be launched in 2018 and 2019, respectively. GEO-KOMPSAT-2 will be launched and injected into the GTO (Geostationary Transfer Orbit) by the Ariane V launcher. Once injected into the GTO, the satellites are transferred to the drift orbit by applying a series of apogee engine burns. The burn epoch time, duration, and intervals are selected such that the satellite is placed closest to the target drift longitude, or at the drift start longitude. For GEO-KOMPSAT-2, four or five LAE (Liquid Apogee Engine) burns will be applied for drift orbit injection. This paper establishes the GEO-KOMPSAT-2 LAE burn plan, considering predefined constraints and adjustments, taking into account the perturbing forces. Two approaches have been analyzed: the first is a single shot approach, whereas the other is an iteration based optimal solution. Optimal solution has been obtained using the Focusleop, a geostationary satellite LEOP tool.

• Journal of Astronomy and Space Sciences
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• v.21 no.2
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• pp.153-166
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• 2004

Interplanetary trajectories using the gravity assists are studied for future Korean interplanetary missions. Verifications of the developed softwares and results were performed by comparing data from ESA's Mars Express mission and previous results. Among the Jupiter exploration mission scenarios, multi-planet gravity assist mission to Jupiter (Earth-Mars-Earth-Jupiter Gravity Assist, EMEJGA trajectory) requires minimum launch energy ($C_3$) of 29.231 $Km^2$/$S^2$ with 4.6 years flight times. Others, such as direct mission and single-planet(Mars) gravity assist mission, requires launch energy ($C_3$) of 75.656 $Km^2$/$S^2$ with 2.98 years flight times and 63.590 $Km^2$/$S^2$ with 2.33 years flight times, respectively. These results show that the planetary gravity assists can reduce launch energy, while EMEJGA trajectory requires the longer flight time than the other missions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.677-682
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• 2016

Recently, because Global Positioning System (GPS) achieves accuracy for engagement of enemy targets, GPS guided weapons have a wide range of applications from land through sea to air. Especially, when GPS guided weapon is then launched, it reads current position and searches a course to the target. As we all know, because GPS signals are weak, these signals can be affected by interference. If jamming signal is strong enough, it can jam the receiver of GPS guided weapon. Therefore, anti-jamming technique is an important thing under these conditions. In this paper, the controlling azimuth angle was used to improve navigation performance of precision guided missile under jamming conditions. First of all, precision missiles by GPS positioning such as SLAM-ER and JDAM were investigated. Also, the azimuth cutoff angle of satellites for usable navigation under jamming signals was analyzed by experimental tests. As a result, we found that azimuth cutoff angle under 140 degree can help ensure continuous GPS reception under the missile guidance.

• Aerospace Engineering and Technology
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• v.2 no.2
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• pp.66-75
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• 2003

A high intensity acoustic test facility has been constructed at Korea Aerospace Research Institute (KARI). Spacecrafts are tested in the facility to check the reliability on acoustic environment of launch vehicles. The reverberant chamber of the facility has a volume of 1,228 cubic meters and provides an acoustic environment of 152 dB over the frequency range of 25 Hz to 10,000 Hz. This paper describes how the basic parameters of the facility including a chamber and power generation system are designed. Moreover, design parameters including acoustic spectrum, acoustic modulator characteristics, reverberation time and isolation characteristics are experimentally verified during acceptance tests.

• Journal of Satellite, Information and Communications
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• v.6 no.1
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• pp.109-114
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• 2011

Ka-band payload of COMS (Communication, Ocean and Meteorological Satellite) launched in June 2010 was developed by ETRI with Korean local companies and also the in-orbit test (IOT) for the Ka-band payload was carried out entirely with domestic technology. The Ka-band payload IOT consisted of the antenna pattern measurements and the payload RF performance test was performed during about 40 days from 10 days after the launch. In this paper, the IOT methods and the results for the Ka-band payload are described in detail. According to the comparisons of each IOT test result with the corresponding ground test result, we can show that the Ka-band payload IOT and verification was successfully achieved and that all Ka-band channels of COMS are to be normal.

• Aerospace Engineering and Technology
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• v.10 no.1
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• pp.98-106
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• 2011

This paper is summarized for designing launch vehicle autopilot structure with attitude angle command from guidance algorithm and for evaluating performance of autopilot using launch vehicle six-degree of freedom simulation program. The suggested autopilot has heritage from KSR-III/KSLV-I upper stage autopilot designing experience, and it has two design point. The one is, it must have same performance with KSR-III/KSLV-I upper stage autopilot, the other is, it must be simple autopilot structure and use low number of variable to apply on-board system. It is evaluated the performance using launch vehicle six-degree of freedom simulation program in case of roll maneuvering and no roll control flight condition.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.96-99
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• 2012

The test facility for confirming performance of a propulsion system is essential infra-structure to develop launch vehicle system. Using the PSTC, cold flow and combustion tests are performed to the propulsion system of individual stage in launcher. Moreover the ground test for the total launching process is conducted. In order to construct the PSTC, we not only have surveyed technology of internal and external countries, but also actively use the case in terms of the system. The test facility consists of feeding system, test stand, control and measurement, and flame deflector.

• Defense and Technology
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• no.2 s.168
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• pp.46-53
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• 1993

첨단과학 기술을 이용한 무기체계의 개발추세에서도 박격포가 다른 무기체계로 대체되지 않고 각광을 받고 있는 이유는, 야포와 비교해 볼때 구조의 단순성, 고사각 사격기능, 살상효과 우수 기동성 우수, 높은 발사속도 등의 장점을 가지고, 야포와 더불어 화력지원용으로 최일선에서 긴요하게 사용되기 때문이다

• Defense and Technology
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• no.3 s.121
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• pp.52-61
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• 1989

화력장비혁명의 내용을 알려면 단순히 정밀유도무기나 레이저 유도무기군만을 볼것이 아니라 전반적인 화력장비 차원에서의 잠재력을 살펴야 한다. 화력장비의 성능은 감시능력, 목표식별, 목표포착, 발사계획 및 조종통제, 파괴력 그리고 각 구성체계간의 신뢰성 있는 통신 능력에 달려있다. 이러한 기반위에서 각 요소들은 계속 기술적으로 발전하고 있다. 우리는 컴퓨터나 발전된 통신기술에 의해서 우선적으로 가능하게 된 자동전투관리시스템(ABMS)의 발전을 생각해야 한다

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.12
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• pp.1207-1215
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• 2008

Satellite generates a complex electromagnetic noise by conducted and radiated coupling effect of the various electrical instruments. This noise may cause serious problems on the satellite system. To minimize the electromagnetic coupling effects and maintain the system safety margin, system noise reduction technique should be applied from the beginning of the system design. The COMS system is evaluated by measuring the conducted noise on system electrical power leads at PSR(Power Supply Regulator) and verifying a 6 dB system safety margin under the complex noise environment with current injection. The radiated noise due to the complex transmit antenna configuration is evaluated by integrating all unit-level RE measurement results, and the RF compatibility between spacecraft and launch vehicle is analyzed with the above estimations. This paper describes the COMS EMC compatibility analysis with respect to each unit level EMC test results, and RF compatibility analysis between spacecraft and launch vehicle. The analyzed results will be reflected on FM(Flight Model) EMC test.