• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
• /
• pp.191-196
• /
• 2006

In GPS Positioning, the error of satellite orbit will affect user's position accuracy directly, it is important to determine the satellite orbit precise. The real-time orbit is needed in kinematic GPS positioning, the precise GPS orbit from IGS would be delayed long time, so orbit prediction is key to real-time kinematic positioning. We analyze the GPS predicted ephemeris, on the base of comparison of EKF and UKF, a new orbit prediction method is put forward based on UKF in this paper, the result shows that UKF improves the orbit predicted precision and stability. It offers a new method for others satellites orbit determination as Galileo, and so on.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
• /
• 한국우주과학회 2004년도 한국우주과학회보 제13권2호
• /
• pp.376-379
• /
• 2004

Operational orbit determination (OOD) depends on the capability of generating accurate prediction of spacecraft ephemeris in a short period. The predicted ephemeris is used in the operations such as instrument pointing and orbit maneuvers. In this study the orbit prediction problem consists of the estimating diverse arc length orbit using GPS navigation data, the predicted orbit for the next 48 hours, and the fitted 30-hour arc length orbits of double differenced GPS measurements for the predicted 48-hour period. For 24-hour orbit arc length, the predicted orbit difference from truth orbit was 205 meters due to the along-track error. The main error sources for the orbit prediction of the Low Earth Orbiter (LEO) satellite are solar pressure and atmosphere density.

• 한국항공우주학회지
• /
• 제42권3호
• /
• pp.270-278
• /
• 2014

본 논문에서는 우주물체 궤도예측의 개선 방안에 관하여 기술하였다. 운용위성과 우주물체와의 근접 가능성 여부를 확인하기 위해 이용되는 TLE(Two-Line Element)를 가관측으로 사용하였고, 비행역학시스템을 통해 궤도결정 및 예측을 수행하였다. 궤도를 결정함에 있어 일정기간 내 일련의 TLE를 이용하여 상태벡터를 가정하였고, 결정기간 및 가관측수(pseudo-observations)에 따른 예측결과 오차를 분석하였다. 또한, 제안된 방식을 적용할 경우 궤도예측 정밀도가 향상 되는지를 알아보기 위해 수 미터 수준의 정밀궤도 확인이 가능한 아리랑위성 2, 3호를 대상으로 먼저 적용하였으며, 동일한 조건으로 우주물체에 적용한 결과를 분석하였다. 우주물체 궤도예측의 RMS 오차 비교 결과, 7일 전파기준으로 궤도 예측 정밀도를 약 90% 향상시킬 수 있었다. 우주물체의 개선된 궤도예측은 매일 수행되는 충돌가능성 분석에 이용되어 위험성이 높은 근접 우주물체의 1차적인 선별에 활용가능 할 것이다.

• Journal of Astronomy and Space Sciences
• /
• 제19권2호
• /
• pp.89-96
• /
• 2002

General along-track acceleration was estimated in the KOMPSAT-1 orbit determination process. Several sets of the atmospheric drag and solar radiation pressure coefficients were also derived with the different spacecraft area. State vectors in the orbit determination with the different spacecraft area were compared in the time frame. The orbit prediction using the estimated coefficients was performed and compared with the orbit determination results. The orbit prediction with the different general acceleration values was also carried out for the comparison

• Journal of Positioning, Navigation, and Timing
• /
• 제12권2호
• /
• pp.167-176
• /
• 2023

This study presents the performance analysis of real-time orbit determination and prediction for navigation message generation of Regional Navigation Satellite System (RNSS). Since the accuracy of ephemeris and clock correction in navigation message affects the positioning accuracy of the user, it is essential to construct a ground segment that can generate this information precisely when designing a new navigation satellite system. Based on a real-time architecture by an extended Kalman filter, we simulated orbit determination and prediction of RNSS satellites in order to assess the accuracy of orbit and clock prediction and signal-in-space ranging errors (SISRE). As a result of the simulation, the orbit and clock accuracy was at 0.5 m and 2 m levels for 24 hour determination and six hour prediction after the determination, respectively. From the prediction result, we verified that the SISRE of RNSS for six hour prediction was at a 1 m level.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.92.4-92
• /
• 2001

Estimation of the general along-track acceleration was performed in the KOMPSAT-1 orbit determination process. Several sets of the atmospheric drag and solar radiation pressure coefficients were also derived with the different spacecraft area. State vectors in the orbit determination with the different spacecraft area were compared in the time frame. The orbit prediction using the estimated coefficients was performed and compared with the orbit determination results. The orbit prediction with the different general acceleration values was also carried out for the comparison.

• 항공우주기술
• /
• 제7권1호
• /
• pp.223-228
• /
• 2008

본 논문에서는 아리랑위성 2호의 영상촬영 계획 절차를 살펴보고, 각 단계에서 발생할 수 있는 궤도예측 오차를 분석하였다. 이를 위해 영상촬영 계획을 수립하는 PSS와 명령계획을 작성하는 MAPS에서 각각 계산된 자세정보를 상호 비교하여 궤도예측 오차의 원인을 규명하였다. 또한, 아리랑위성 2호의 실제 영상자료를 이용하여 촬영된 영상의 중심점과 미리 계획된 목표지점 사이의 이탈거리인 촬영 지향오차를 계산하였다. 영상촬영 계획은 실제 촬영일보다 이전에 수행되어 궤도예측 오차를 어느 정도 포함하게 되므로, 영상촬영 계획 시 일정한 Margin을 적용해야 할 것으로 판단된다.

• 한국정밀공학회지
• /
• 제9권3호
• /
• pp.157-164
• /
• 1992

This study concerns about the orbit prediction and orbit determination of Korean future communication satellite, called 'Moogunghwa", which will be motioned in the geo-stationary orbit. Perturbation effect on the satellite orbit due to nonspherical gravitation of the earth, gravitation of the sun and moon, radiation of sun, drag of the atmosphere was investigated. Cowell's method is used for orbit prediction. Orbit determination was performed by using Extended Kalman Filter which is suitable for real-time orbit determination. The result shows that the chacteristics of the satellite orbit has east-west and south-north drift. So the periodic control time and control value in the view of the periodic of error can be provided. The orbit determination demonstrated the effectiveness since the convergence performance on the positon and velocity error, and state error standard deviation is reasonable.able.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
• /
• pp.692-697
• /
• 1992

This study concerns about the orbit prediction and orbit determination of Korean future communication satellite, called "Moogunghwa", which will be motioned in the geo-stationary orbit. Perturbation effect on the satellite orbit due to nonspherical geopotential term, lunar and solar gravity, drag force of the atmosphere and solar radiation pressure was investigated. Cowell's method is used for orbit prediction. Orbit determination was performed by using EKF which is suitable for real-time orbit determination. The result shows that the characteristics of the satellite orbit has drift. So the periodic control time and control value in the view of the periodic of error can be provided. The orbit determination demonstrated the effectiveness since the convergence performance on the position and velocity error , and state error standard deviation is reasonable.easonable.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1992년도 춘계학술대회 논문집
• /
• pp.200-205
• /
• 1992

This study concerns about the orbit prediction and orbit determination of Korean future connumication satellite, called "Moogunghwa" , which will be motioned in the geo-stationary orbit. Perturbation effect on the satellite orbit due to nonspherical term, lunar and solar gravity, drag force of the atmospher, and solar radiation pressure was investigated. Cowell's method is used for orbit prediction. Orbit determination was performed by using Extended Kalman Filter which is suitable for real-time orbit determination. The result shows that the chacteristics of the satellite orbit has east-west and south-north drift. So the periodic control time and control value in the view of the periodic of error can be provided. The orbit determination demonstrated the effectiveness since the convergence performance on the positon and velocity error, and state error standard deviation is reasonable.