• Title/Summary/Keyword: Non-geostationary Orbit

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Analysis of Interference Effect Between Geostationary Orbit Link and Non-Geostationary Orbit Link (정지궤도 위성망과 비정지궤도 위성망간의 간섭영향 분석)

  • Kang, Chul-Gyu;Park, Cheol-Sun;Oh, Chang-Heon
    • Journal of Advanced Navigation Technology
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    • v.13 no.3
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    • pp.344-350
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    • 2009
  • In this paper, interference effect given from non-geostationary orbit link into geostationary orbit link is analyzed by BER performance. To analyze the interference effect with the angle between satellites, the angular separation is changed from $1^{\circ}$ to $8^{\circ}$, and the number of the satellite is also changed from 1 to 4 for analyzing it. From the results, the interference effect into the geostationary orbit service from non-geostationary orbit link is more increased according to the angular separation that is decreased. Especially, the small angle gives more interference effects to the geostationary orbit link. Furthermore, more number of interfering satellites gives more interference effect to the geostationary orbit link. However, the angle between the interference orbit and geostationary orbit gives more effect to the system performance then the number of the interference orbit.

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Interference Effect Analysis of Geostationary Orbit Link from Non-Geostationary Orbit Link (정지궤도 위성망과 비정지궤도 위성망간의 간섭영향 분석)

  • Kang, Chul-Gyu;Joung, Seung-Hee;Choi, Young-Seok;OH, Chang-Heon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.05a
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    • pp.919-923
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    • 2009
  • In this paper, interference effect given from non-geostationary orbit link into geostationary orbit link is analyzed by BER performance curve. To analyse the interference effect with the angle between satellites, the angular separation is changed from $1^{\circ}$ to $8^{\circ}$, and the number of the satellite is also changed from 1 to 4 for analyzing it. From the result under those research environments, the interference effect into the geostationary orbit service is more increased according to the angular separation that is decreased. Especially, the small angle gives more interference effects to the geostationary orbit link. Furthermore, more number of interfering satellites gives more interference effect to the geostationary orbit link.

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A Study on the Sharing Criteria Between NGSO/FSS and HDFS (NGSO/FSS와 HDFS간 공유 기준에 관한 연구)

  • 강병수;권태곤;이성팔
    • Proceedings of the IEEK Conference
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    • 2000.11a
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    • pp.465-468
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    • 2000
  • The interference situation for the satellite networks using non-geostationary satellite orbit (NGSO) is more complicated than the situation between geostationary satellite orbit (GSO) networks because of the time varying orbital characteristics of NGSO systems. Most of frequency bands are allocated to fixed-satellite service and liked-service in co-primary basis. In this paper, the sharing criteria between NGSO/FSS systems and HDFS (High Density Fixed-Service) are examined.

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SUN TRANSIT OUTAGE CONSIDERING SOLOR ACTIVITY AND IT'S APPLICATION TO KOREASAT (태양활동을 고려한 태양간섭현상 연구와 무궁화 위성에의 응용)

  • 노경민;최규홍;배석희
    • Journal of Astronomy and Space Sciences
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    • v.16 no.1
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    • pp.53-60
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    • 1999
  • The purpose of this paper is to predict Sun Transit Outage phenomenon(Sunout). Sunout had been studied mainly for the case of Geostationary satellite and under the assumption of 'Quiet Sun'. In this paper, we predict sunout phenomenon more precisely for non-geostationary orbit as well as geostationary orbit and specially we considered the degree of solar activity. And we compare the result of the case of C-band and Ku-band. Also the result is applied to the two KoreaSat communication system through calculating the link budget.

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A Study on the Station Relocation of the Koreasat (무궁화위성의 궤도재배치에 관한 연구)

  • Lee, Sang-Cherl;Park, Bong-Kyu;Kim, Bang-Yeop
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.8
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    • pp.87-93
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    • 2002
  • In general, station relocation for a geostationary orbit satellite is formulated as a request for moving the spacecraft from its present longitude to the target longitude within a given time interval. The station relocation maneuver is composed of drift orbit insertion maneuver and target orbit insertion maneuver. During station relocation, the satellite orbit is continually influenced by the non-spherical geo-potential. When we plan a maneuver, if we do not consider the influence, the satellite may not be relocate to desired longitude successfully. To solve this problem, we applied the linearised orbit transfer equation to acquire maneuver time and delta-V. Nonlinear simulation for the station relocation of multiple satellites is performed in order to verify the distance between two satellites.

Radio Propagation Characteristics Analysis of Non-geostationary Satellite(COMETS) in Clear Sky (Clear Sky에서 비정지궤도 위성(COMETS)의 전파특성 분석)

  • 김양수;최용석;이주환;김종호;이형수
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.1
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    • pp.93-101
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    • 2000
  • In this paper, propagation characteristics are analyzed under the Korean propagation condition based on the measurements for Ka-band beacon signal of COMET satellite which moves in non-geostationary orbit. Radio propagation characteristics varying as time, range, and elevation angle are presented also. As results, it is concluded that free space loss is a major parameter to the radio propagation characteristics varying as a range in clear sky. In addition, the effect of elevation angle is negligible because COMETS is observed above 40 degree.

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Simulator Development for GEO (Geostationary Orbit)-Based Launch Vehicle Flight Trajectory Prediction System (정지궤도 기반 발사체 비행 궤적 추정시스템의 시뮬레이터 개발)

  • Myung, Hwan-Chun
    • Journal of Space Technology and Applications
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    • v.2 no.2
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    • pp.67-80
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    • 2022
  • The missile early-warning satellite systems have been developed and upgraded by some space-developed nations, under the inevitable trend that the space is more strongly considered as another battle field than before. As the key function of such a satellite-based early warning system, the prediction algorithm of the missile flight trajectory is studied in the paper. In particular, the evolution computation, receiving broad attention in the artificial intelligence area, is applied to the proposed prediction method so that the global optimum-like solution is found avoiding disadvantage of the previous non-linear optimization search tools. Moreover, using the prediction simulator of the launch vehicle flight trajectory which is newly developed in C# and Python, the paper verifies the performance and the feature of the proposed algorithm.

The Analysis on the Effects of Interference between HAPS and NGSO System in the Service Link (HAPS와 NGSO 시스템의 Service Link상의 간섭영향)

  • Yang, Eui-Jang;Kim, Kyu-Hwan;Ham, Hyung-Il;Kang, Yung-Heung
    • Journal of Advanced Navigation Technology
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    • v.7 no.1
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    • pp.22-29
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    • 2003
  • In this paper, we analyze the interference effects between NGSO(Non-Geostationary Orbit) and HAPS(High Altitude Platform System) by dividing into two cases. The one is interference effects of HAPS into NGSO, the another is the interference effects of NGSO into HAPS. At the result, we canknow the interference effect into NGSO mobile station is the highest when position of NGSO is $95^{\circ}$. In this case, we can also know the interference effects from both HAPS and NGSO exceed interference criteria when the number of users are more than 20. And, in the case of the interference effect into HAPS mobile station, we can know it is the highest when elevation angle of NGSO is $87^{\circ}$, and the interference effects from both NGSO and HAPS exceed interference criteria when the number of users is more then 10. Moreover, the interference effect is the minimum, when elevation angle of NGSO is $64^{\circ}$, at this time, in case that the number of users of NGSO equal to the number of user of HAPS, the interference effects exceed interference criteria when the number of users is 190.

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MEAN ORBITAL ELEMENTS FOR GEOSYNCHRONOUS ORBIT-I. -Semi-major, eccentricity, and longitude of perigee- (정지 위성 궤도의 평균 궤도 요소-I -궤도의 장반경, 이심률, 근지점 경도-)

  • 최규홍;이정숙;박종옥;문인상
    • Journal of Astronomy and Space Sciences
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    • v.6 no.2
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    • pp.91-100
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    • 1989
  • The mean orbital elements for geosynchronou8s satellite are developed in terms of non-singular orbital elements. The true satellite position oscillates about the position calculated from the mean elements due to short period perturbations to the satellite motion. The displacement of a geostationary satellite from this mean orbit position is less than 1800m. The mean elements of ec are obtained.

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Fading channel modeling for non-geostationary orbit mobile satellite communication systems (비정지궤도 이동위성통신시스템에서의 페이딩 채널 모델링)

  • You, Moon-Hee;Park, Se-Kyoung;Lee, Soo-In
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.35S no.11
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    • pp.12-18
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    • 1998
  • In non-geostationary orbit(NGSO) satellite communication links, satellite's elevation angle at terminal is changed continuously because of the satellite movement relative to earth surface. Therefore the characteristics of the fade-effected signal received by a terminal from a NGSO satellite is also varied continuously even if the terminal is operated at fixed location. In this paper, we determine a general statistic model for the fading characteristics over NGSO satellite communication links and set up the parameters of the fading model in terms of the elevation angle according to various propagation environment and find the parameter values using the data of fading margin for commercial NGSO mobile satellite communication systems. And the fading charateristics for each environment are analyzed using this model. These results can be applied to develop the compensation algorithm and to analyze the performance of the transmission schemes for NGSO mobile satellite communication systems.

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