• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
• /
• pp.457-462
• /
• 1990

Lately, at an epock of full-scale satellite ranching plan of Korea, T.T.C (Tracking, Telemetery & Command) is a indispensable part. In this paper, particular attention is given to orbit determination problem of role of T.T.C. Orbit determination, which is applied to Kalman Filter and Smoothing Filter, use the observation data which is given by satellite tracking radar system, and then the simulation is accomplished. As a result, it shows effectiveness.

• 항공우주시스템공학회지
• /
• 제9권2호
• /
• pp.57-62
• /
• 2015

The satellite orbit is continuously changing due to space environment. Especially for low earth orbit, atmospheric drag plays an important role in the orbit altitude decay. Recently, solar activities are expected to be high, and relevant events are occurring frequently. In this paper, analysis on the impact of geomagnetic storm on LEO satellite orbit is presented. For this, real flight data of KOMPSAT-2, KOMPSAT-3, and KOMPSAT-5 are analyzed by using the daily decay rate of mean altitude is calculated from the orbit determination. In addition, the relationship between the solar flux and geomagnetic index, which are the metrics for solar activities, is statistically analyzed with respect to the altitude decay. The accuracy of orbit prediction with both the fixed drag coefficient and estimated one is examined with the precise orbit data as a reference. The main results shows that the improved accuracy can be achieved in case of using estimated drag coefficient.

• Korean Journal of Mathematics
• /
• 제21권3호
• /
• pp.271-283
• /
• 2013

In this paper, a generalized Adams-Moulton method that is a $m$-step method derived by using the Taylor's series is proposed to solve the satellite orbit determination problem. We show that our proposed method has produced much smaller error than the original Adams-Moulton method. Finally, the accuracy performance is demonstrated in the satellite orbit correction problem by giving a numerical example.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
• /
• pp.783-787
• /
• 1993

The dynamics for a two-body problem including perturbations due to nonspherical gravitation of the earth, gravitation of the sun and moon, radiation of the sun is studied. Orbit determination was performed by SVD filter. The simulation result shows that the characteristics of the satellite orbit have east-west and south-north drift. Therefore, the periodic magnitude of the control time and value in the view of the periodicity of error can be provided, and this result can be basic data to a station keeping problem with an orbit determination result.

• Journal of Astronomy and Space Sciences
• /
• 제35권4호
• /
• pp.227-233
• /
• 2018

This study presents the generation and accuracy assessment of predicted orbital ephemeris based on satellite laser ranging (SLR) for geostationary Earth orbit (GEO) satellites. Two GEO satellites are considered: GEO-Korea Multi-Purpose Satellite (KOMPSAT)-2B (GK-2B) for simulational validation and Compass-G1 for real-world quality assessment. SLR-based orbit determination (OD) is proactively performed to generate orbital ephemeris. The length and the gap of the predicted orbital ephemeris were set by considering the consolidated prediction format (CPF). The resultant predicted ephemeris of GK-2B is directly compared with a pre-specified true orbit to show 17.461 m and 23.978 m, in 3D root-mean-square (RMS) position error and maximum position error for one day, respectively. The predicted ephemeris of Compass-G1 is overlapped with the Global Navigation Satellite System (GNSS) final orbit from the GeoForschungsZentrum (GFZ) analysis center (AC) to yield 36.760 m in 3D RMS position differences. It is also compared with the CPF orbit from the International Laser Ranging Service (ILRS) to present 109.888 m in 3D RMS position differences. These results imply that SLR-based orbital ephemeris can be an alternative candidate for improving the accuracy of commonly used radar-based orbital ephemeris for GEO satellites.

• International Journal of Aerospace System Engineering
• /
• 제7권2호
• /
• pp.6-12
• /
• 2020

The precise prediction of future position of satellite depends on the accurate determination of orbit, which is also helpful in performing orbit maneuvers and trajectory correction maneuvers. For estimating the orbit of satellite many methods are being used. Some of the conventional methods are based on (i) Differential Correction (DC) (ii) Extended Kalman Filter (EKF). In this paper, Differential Evolution (DE) is used to determine the orbit. Orbit Determination using DC and EKF requires some initial guess of the state vector to initiate the algorithm, whereas DE does not require an initial guess since a wide range of bounds for the design unknown variables (orbital elements) is sufficient. This technique is uniformly valid for all orbits viz. circular, elliptic or hyperbolic. Simulated observations have been used to demonstrate the performance of the method. The observations are generated by including random noise. The simulation model that generates the observations includes the perturbation due to non-spherical earth up to second zonal harmonic term.

• Journal of Astronomy and Space Sciences
• /
• 제27권4호
• /
• pp.345-352
• /
• 2010

Korea multi-purpose satellite-5 (KOMPSAT-5) is a low earth orbit (LEO) satellite scheduled to be launched in 2010. To satisfy the precision orbit determination (POD) requirement for a high resolution synthetic aperture radar image of KOMPSAT-5, KOMPSAT-5 has atmosphere occultation POD (AOPOD) system which consists of a space-borne dual frequency global positioning system (GPS) receiver and a laser retro reflector array. A space-borne dual frequency GPS receiver on a LEO satellite provides position data for the POD and radio occultation data for scientific applications. This paper describes an overview of AOPOD system and operation concepts of the radio occultation mission in KOMPSAT-5. We showed AOPOD system satisfies the requirements of KOMPSAT-5 in performance and stability.

• 항공우주기술
• /
• 제4권2호
• /
• pp.88-93
• /
• 2005

정지궤도 위성을 대상으로 각도 정보를 기반으로 하는 궤도결정 기술에 대한 개념 연구를 수행하였다. 정지궤도 위성의 관측 영역에 지구와 부근의 별이 동시에 촬영된다는 가정하에 지구와 별의 시야각 정보가 궤도결정의 입력으로 사용될 수 있음을 확인하였다. 최소자승법 알고리즘과 MATLAB을 사용한 시뮬레이션에서 그 수렴성을 확인할 수 있었다. 이러한 개념 연구의 대상 위성으로 통신해양기상위성을 가정하였다. 이러한 기술은 지상국의 궤도 결정의 보조 방법 또는 위성운용 자동화의 일부분으로 응용될 수 있을 것이다.

• International Journal of Aeronautical and Space Sciences
• /
• 제18권2호
• /
• pp.327-333
• /
• 2017

This study presents the orbit determination (OD) of a candidate Korea Regional Navigation Satellite System (KRNSS) using both inter-satellite links (ISLs) and ground observations. The candidate constellation of KRNSS is first introduced. The OD algorithm based on both ISL and ground observation is developed, and consists of three main components: dynamic model for Korean navigation satellites, measurement model for ISLs and ground observations, and the batch least-square filter for estimating OD parameters. As numerical simulations are performed to analyze the OD performances, the present study focuses on investigating the effects of ISL measurements on the OD accuracy of KRNSS. Simulation results show that the use of ISLs can considerably enhance the OD accuracy to one meter (design preference) under certain distributions of ground stations.

• 한국항공우주학회지
• /
• 제42권8호
• /
• pp.661-673
• /
• 2014

본 논문에서는 한국항공우주연구원에서 개발한 우주파편 충돌위험 종합관리 시스템(KARISMA, KARI Collision Risk Management System)의 궤도결정 기능을 이용하여, 정지궤도위성의 광학 관측데이터에 기반한 정밀궤도결정을 수행하였다. 광학 관측데이터로는 정지궤도 위성 ARTEMIS에 대한 유럽우주기구(ESA, European Space Agency)의 실제 광학 관측데이터를 사용하였다. 동일한 관측데이터에 대해 유럽우주기구의 정밀궤도결정 시스템을 통해 얻은 궤도결정 결과와 비교했을 때 약 420 m 정도의 평균 위치오차가 있음을 확인하였다. 또한, 4일간의 광학 관측데이터를 바탕으로 얻은 궤도결정 결과를 이용하여 궤도예측을 수행하였으며, 유럽우주기구의 궤도결정 결과와 비교했을 때 3일 동안 대략 500~600 m 수준의 위치오차를 보였다. 이러한 결과들에 기반하여 KARISMA의 궤도결정 성능이 우주파편 충돌위험 분석을 위해 사용가능한 수준임을 확인할 수 있었다.