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1984년 ~ 2025년까지 1,253 건의 한국우주과학회지를 계간으로 확인하실 수 있습니다.
- The Korean Space Science Society (The Korean Astronomical Society)
- 계간 (Quarterly)
- ISSN : 1225-052x (ISSN : 1225-052x)
1225-052x
- DB구축현황 : 1,253건 (DB Construction : 1,253 Articles)
총 게시글 1,253건
페이지 53/126
521
- Song, Yong-Jun
- 韓國宇宙科學會誌 = Journal of astronomy & space sciences
- 27, n.1
- pp.31-42
- 2010
- 원문 바로보기
We developed a computer program to predict solar interference period. To calculate Sun's position, we used DE406 ephemerides and Earth ellipsoid model. The Sun's position error is smaller than 10arcsec. For the verification of the calculation, we used TU media ground station on Seongsu-dong, and MBSAT geostationary communication satellite. We analysis errors, due to satellite perturbation and antenna align. The time error due to antenna align has -35 to +16 seconds at <TEX>$0.1^{\circ}$</TEX>, and -27 to +41 seconds at <TEX>$0.25^{\circ}$</TEX>. The time errors derived by satellite perturbation has 30 to 60 seconds.
522
- Lee, Jae-Yoon
- Journal of astronomy and space sciences
- 27, n.2
- pp.129-134
- 2010
- 원문 바로보기
Rain attenuation can cause a serious problem that an availability of space communication link on Ka band becomes low. To reduce the effect of rain attenuation on the error performance of space communications in Ka band, an adaptive coding and modulation (ACM) scheme is required. In this paper, to achieve a reliable telemetry data transmission, we propose an adaptive coding and modulation level using turbo code recommended by the consultative committee for space data systems (CCSDS) and various modulation methods (QPSK, 8PSK, 4+12 APSK, and 4+12+16 APSK) adopted in the digital video broadcasting-satellite2 (DVB-S2).
523
- Koo, Cheol-Hea
- Journal of astronomy and space sciences
- 27, n.4
- pp.407-412
- 2010
- 원문 바로보기
Software reusability is one of key factors which impacts cost and schedule on a software development project. It is very crucial also in satellite simulator development since there are many commercial simulator models related to satellite and dynamics. If these models can be used in another simulator platform, great deal of confidence and cost/schedule reduction would be achieved. Simulation model portability (SMP) is maintained by European Space Agency and many models compatible with SMP/simulation model interface (SMI) are available. Korea Aerospace Research Institute (KARI) is developing hardware abstraction layer (HAL) supported satellite simulator to verify on-board software of satellite. From above reasons, KARI wants to port these SMI compatible models to the HAL supported satellite simulator. To port these SMI compatible models to the HAL supported satellite simulator, simulation scheduler is preliminary designed according to the SMI standard.
524
- Lee, D.H.
- Journal of astronomy and space sciences
- 27, n.4
- pp.401-406
- 2010
- 원문 바로보기
We have measured and analyzed the dark data of two PICNIC IR arrays (P574 and P560) obtained through the Cosmic Infrared Background ExpeRiment (CIBER). First, we identified three types of bad pixels: the cold, the hot, and the transient, which are figured in total as 0.06% for P574 and 0.19% for P560. Then, after the bad pixels were masked, we determined the dark noise to be 20.5 <TEX>${\pm}$</TEX> 0.05 <TEX>$e^-$</TEX> and 16.1 <TEX>${\pm}$</TEX> 0.05 <TEX>$e^-$</TEX>, and the dark current to be 0.6 <TEX>${\pm}$</TEX> 0.05 <TEX>$e^-$</TEX>/sec and 0.7 <TEX>${\pm}$</TEX> 0.05 <TEX>$e^-$</TEX>/sec for P574 and P560, respectively. Finally, we discussed glitches and readout modes for a future mission.
525
- Kwak, Young-Sil
- Journal of astronomy and space sciences
- 27, n.3
- pp.205-212
- 2010
- 원문 바로보기
To better understand the physical processes that maintain the high-latitude lower thermospheric dynamics, we have identified relative contributions of the momentum forcing and the heating to the high-latitude lower thermospheric winds depending on the interplanetary magnetic field (IMF) and altitude. For this study, we performed a term analysis of the potential vorticity equation for the high-latitude neutral wind field in the lower thermosphere during the southern summertime for different IMF conditions, with the aid of the National Center for Atmospheric Research Thermosphere-Ionosphere Electrodynamics General Circulation Model (NCAR-TIEGCM). Difference potential vorticity forcing and heating terms, obtained by subtracting values with zero IMF from those with non-zero IMF, are influenced by the IMF conditions. The difference forcing is more significant for strong IMF <TEX>$B_y$</TEX> condition than for strong IMF <TEX>$B_z$</TEX> condition. For negative or positive <TEX>$B_y$</TEX> conditions, the difference forcings in the polar cap are larger by a factor of about 2 than those in the auroral region. The difference heating is the most significant for negative IMF <TEX>$B_z$</TEX> condition, and the difference heatings in the auroral region are larger by a factor of about 1.5 than those in the polar cap region. The magnitudes of the difference forcing and heating decrease rapidly with descending altitudes. It is confirmed that the contribution of the forcing to the high-latitude lower thermospheric dynamics is stronger than the contribution of the heating to it. Especially, it is obvious that the contribution of the forcing to the dynamics is much larger in the polar cap region than in the auroral region and at higher altitude than at lower altitude. It is evident that when <TEX>$B_z$</TEX> is negative condition the contribution of the forcing is the lowest and the contribution of the heating is the highest among the different IMF conditions.
526
- Seo, Yoon-Kyung
- Journal of astronomy and space sciences
- 27, n.4
- pp.393-400
- 2010
- 원문 바로보기
Korea Astronomy and Space Science Institute has been developing one mobile satellite laser ranging system named as accurate ranging system for geodetic observation-mobile (ARGO-M). Preliminary design of ARGO-M operation system (AOS) which is one of the ARGO-M subsystems was completed in 2009. Preliminary design results are applied to the following development phase by performing detailed design with analysis of pre-defined requirements and analysis of the derived specifications. This paper addresses the preliminary design of the whole AOS. The design results in operation and control part which is a key part in the operation system are described in detail. Analysis results of the interface between operation-supporting hardware and the control computer are summarized, which is necessary in defining the requirements for the operation-supporting hardware. Results of this study are expected to be used in the critical design phase to finalize the design process.
527
- Kim, Chun-Hwey
- Journal of astronomy and space sciences
- 27, n.4
- pp.263-278
- 2010
- 원문 바로보기
Many filtered CCD measures form the basis of six new light curves of the eclipsing system SW Lyn. From these measures and additional observations for eclipse timing, 47 new times of minimum light over the time-interval of about 13 years have been calculated. The complex period variability can be sorted into a linear period improvement with 5.8-year and 33.9-year periodic terms. The shorter cyclic term of these is ascribed to a cool companion of the eclipsing pair but the longer one has no testable interpretation at present. The new light curves are synthesized by the 2003 version of the Wilson-Devinney differential corrections computer code. The results incorporate a source of 'third light' which comes from the cool companion star that had been identified by the cycling of the period of the eclipsing pair and also had previously been identified spectroscopically. There is a measure of satisfaction with current understanding of the SW Lyn eclipsing system because of consistent syntheses of all historical light curves. This agreeable convergence, however, comes partly at the expense of an unanticipated temperature of the hot star and of a photospheric spot that has no obvious basis in the detached character modeled for the binary. We offer predictions of changes in the stellar parameters if the modeled detached-configuration should be wrong. The SW Lyn stellar system is still difficult to understand.
528
- Kwak, Young-Hee
- Journal of astronomy and space sciences
- 27, n.2
- pp.173-180
- 2010
- 원문 바로보기
As a preparatory study for Global Positioning System-Very Long Baseline Interferometry (GPS-VLBI) hybrid system, we examined if VLBI type observation of the GPS signal is realizable through a test experiment. The test experiment was performed between Kashima and Koganei, Japan, with 110 km baseline. The GPS L1 and L2 signals were received by commercial GPS antennas, down-converted to video-band signals by specially developed GPS down converters, and then sampled by VLBI samplers. The sampled GPS data were recorded as ordinary VLBI data by VLBI recorders. The sampling frequency was 64 MHz and the observation time was 1 minute. The recorded data were correlated by a VLBI correlator. From correlation results, we simultaneously obtained correlation fringes from all 8 satellites above a cut-off elevation which was set to 15 degree. 87.5% of L1 fringes and 12.5% of L2 fringes acquired the Signal to Noise Ratios which are sufficient to achieve the group delay precision of 0.1nsec that is typical in current geodetic VLBI. This result shows that VLBI type observation of GPS satellites will be readily realized in future GPS-VLBI hybrid system.
529
- 박재익
- 韓國宇宙科學會誌 = Journal of astronomy & space sciences
- 26, n.1
- pp.99-110
- 2009
- 원문 바로보기
이 연구의 목적은 편대비행위성의 항법 및 궤도제어를 위한 실시간 Hardware-In-the-Loop(HIL) 시뮬레이션 테스트베드를 개발하는데 있다. HIL 시뮬레이션 테스트베드는 실제와 비슷한 하드웨어 환경을 구성하여 주어진 편대비행임무 요구조건에 따른 새로운 개념의 알고리즘을 테스트할 수 있는 시뮬레이터이다. HIL 시뮬레이션 테스트베드는 실제의 인공위성 시스템 인터페이스와 최대한 유사하게 설계되었으며 환경 컴퓨터, GPS 시뮬레이터, GPS 수신기, 비행제어 컴퓨터, 시각화 컴퓨터 등 총 5개의 독립적인 시스템으로 구성되어 있다. Spirent Communication사의 GSS6560 다중패널 RF 시뮬레이터와, (주)세트렉아이에서 제작한 우주용 GPS 수신기를 사용하여 실제와 유사한 GPS 관측데이터를 사용한다. GPS 수신기로부터 획득한 관측데이터는 비행제어 컴퓨터 시스템으로 전송되고 이를 통해 편대비행위성의 절대위치 및 상대위치결정을 수행하였다. 또한 이 결과를 바탕으로 비행제어 컴퓨터 시스템은 궤도조정에 필요한 제어값을 계산하여 환경 컴퓨터 시스템으로 전송한다. 이렇게 5개의 독립적인 시스템을 유기적으로 통합하여 폐순환반복(closed-loop) HIL 시뮬레이션 테스트베드를 설계하였다. 이 논문에서는 편대비행 위성의 항법 및 제어 알고리즘 테스트를 위한 실시간 HIL 시뮬레이션 테스트베드의 전반적인 구성방법과 세부적인 구성요소에 대해 설명하였다 저궤도 편대비행위성의 편대유지 임무에 대한 가상의 시나리오를 설정하여 위성 편대비행의 항법 및 궤도제어 알고리즘을 실험적으로 검증하였다.
530
- 민병희
- 韓國宇宙科學會誌 = Journal of astronomy & space sciences
- 26, n.3
- pp.329-344
- 2009
- 원문 바로보기
일광절약시간제는 하절기에 낮 시간을 효율적으로 활용하기 위한 것이다. 한국은 해방이후부터 1988년까지 12번의 일광절약시간제를 시행하였다. 지난 20여년간 이 제도가 실시되지 않았으나, 최근에 일광절약시간제의 시행에 관한 문제가 다시 제기되고 있다. 이 논문에서는 세계 여러 국가의 일광절약시간제 시행경향, 한국의 일광절약시간제 실시의 역사를 살펴보고, 일출 몰시각 변화에 따른 낮의 길이 변화를 계산해 한국에 적합한 일광절약시간제 시행시기를 연구하였다. 한국은 동경 <TEX>$135^{\circ}$</TEX> 표준자오선을 사용하고 있는데, 일출시각과 표준자오선의 지역적 치우침을 고려해 계산한 결과, 5월 두번째 일요일이나 4월 두번째 일요일이 적절한 일광절약시간제의 시작시기임을 알아내었다. 또한 일광절약시간제를 시행할 경우 발생하는 한국표준시에 대한 시간마찰과 이에 파생되는 문제들을 논하였다.