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정지궤도 위성의 LAE Burn Strategy Planning
김방엽(Bang-Yeop Kim),이호형(Ho-Hyoung Lee) 한국항공우주연구원 2007 항공우주기술 Vol.6 No.2
정지궤도 위성의 전이궤도 해석 과정의 중요한 부분인 LAE(Liquid Apogee Engine, 액체원지점엔진) 분사전략 수립을 위한 프로그램을 개발하였다. 본 프로그램에서 다루고 있는 LAE 분사전략 수립은 전이궤도 해석의 첫 단계로서, 초기 전이궤도 요소와 지상 TT&C 중계소의 위치, 위성체 성능 파라미터를 입력받아 여러 제한 조건을 만족하면서 선택 가능한 분사 전략들을 계산하는 과정이다. 본 연구에서 개발된 프로그램은 일반적인 LAE를 사용하는 정지궤도 위성을 대상으로 하였으며 최대 여섯 개의 예비 분사 전략과 최대 6회까지 LAE를 분사하는 상황을 가정하였다. 본 프로그램에서 입출력 부분에는 MS-엑셀이 사용되었으며 계산 과정은 MATLAB 함수를 사용하여 구현되었다. A program for LAB (liquid Apogee Fngine) firing strategy calculation was developed. This program can be used as the first stage of transfer orbit analysis, which process receives input parameters as like initial orbit elements, ground IT&C stations positions, satellite performances and makes firing user-selectable strategies. The developed program is dedicated to GEO satellites which using LAE generally and it can calculate six hick-up strategies and deals situation its maximum firing number is six. The MS-EXCEL software was used for the input and output process. And the numerical calculation part was embodied with MATLAB functions.
Geostationary Transfer Orbit Mission Analysis Software Development
Kim, Bang-Yeop 한국우주과학회 2008 한국우주과학회보 Vol.17 No.2
The Korean first geostationary meteorological satellite, COMS, will be launched during second half of 2009. For the next meteorological geostationary satellite mission, KARI is now preparing the development process and tools. As one of the endeavor, a sof
Alternating Sunspot Area and Hilbert Transform Analysis
Kim, Bang-Yeop,Chang, Heon-Young 한국우주과학회 2011 Journal of Astronomy and Space Sciences Vol.28 No.4
We investigate the sunspot area data spanning from solar cycles 1 (March 1755) to 23 (December 2010) in time domain. For this purpose, we employ the Hilbert transform analysis method, which is used in the field of information theory. One of the most important advantages of this method is that it enables the simultaneous study of associations between the amplitude and the phase in various timescales. In this pilot study, we adopt the alternating sunspot area as a function of time, known as Bracewell transformation. We first calculate the instantaneous amplitude and the instantaneous phase. As a result, we confirm a ~22-year periodic behavior in the instantaneous amplitude. We also find that a behavior of the instantaneous amplitude with longer periodicities than the ~22-year periodicity can also be seen, though it is not as straightforward as the obvious ~22-year periodic behavior revealed by the method currently proposed. In addition to these, we note that the phase difference apparently correlates with the instantaneous amplitude. On the other hand, however, we cannot see any obvious association of the instantaneous frequency and the instantaneous amplitude. We conclude by briefly discussing the current status of development of an algorithm for the solar activity forecast based on the method presented, as this work is a part of that larger project.