• Journal of Astronomy and Space Sciences
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• v.38 no.1
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• pp.65-82
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• 2021

For the vast majority of geostationary satellites currently in orbit, station keeping activities including orbit determination and maneuver planning and execution are ground-directed and dependent on the availability of ground-based satellite control personnel and facilities. However, a requirement linked to satellite autonomy and survivability in cases of interrupted ground support is often one of the stipulated provisions on the satellite platform design. It is especially important for a geostationary military-purposed satellite to remain within its designated orbital window, in order to provide reliable uninterrupted telecommunications services, in the absence of ground-based resources due to warfare or other disasters. In this paper we investigate factors affecting the robustness of a geostationary satellite's orbit in terms of the maximum duration the satellite's station keeping window can be maintained without ground intervention. By comparing simulations of orbit evolution, given different initial conditions and operations strategies, a variation of parameters study has been performed and we have analyzed which factors the duration is most sensitive to. This also provides valuable insights into which factors may be worth controlling by a military or civilian geostationary satellite operator. Our simulations show that the most beneficial factor for maximizing the time a satellite will remain in the station keeping window is the operational practice of pre-emptively loading East-West station keeping maneuvers for automatic execution on board the satellite should ground control capability be lost. The second most beneficial factor is using short station keeping maneuver cycle durations.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.458-458
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• 2000

Quick evaluations of two in-plane orbit maneuvers using small see of real-time CPS navigation solutions were peformed lot the KOMPSAT-1 spacecraft operation. Real-time GPS navigation solutions of the KOMPSAT-1 were collected during the Korean Ground Station(KGS) pass. Only a few sets of position and velocity data after completion of the thruster firing were used for the quick maneuver evaluations. The results were used for antenna pointing data predictions for the next station contact. Normal orbit maneuver evaluations using large see of playback GPS navigation solutions were also performed and the result were compared with the quick evaluation results.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.4
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• pp.474-483
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• 2012

In this paper, a collision avoidance maneuver was sought for low Earth orbit (LEO) and geostationary Earth orbit (GEO) satellites maintained in a keeping area. A genetic algorithm was used to obtain both the maneuver start time and the delta-V to reduce the probability of collision with uncontrolled space objects or debris. Numerical simulations demonstrated the feasibility of the proposed algorithm for both LEO satellites and GEO satellites.

• Journal of Astronomy and Space Sciences
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• v.12 no.1
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• pp.102-111
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• 1995

A series of east/west and north/south station-keeping maneuvers were simulated for the KOREAST spacecraft which has to be maintained within $\pm$0.05 at the nominal longitude of $116^{\circ}$E. Weekly an biweekly based station-deeping maneuver plannings were used, and weekend maneuvers were avoided. All of the station-keeping maneuver plannings and executions were performed using KOREASTA Mission Analysis Software on VAX/VMS operating system. Fourteen weeks station-keeping maneuvers were performed and various station-keeping orbital parameters were obtained.

• Journal of Aerospace System Engineering
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• v.4 no.4
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• pp.37-43
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• 2010

Need for agile satellites increases for performing various mission due to increase of satellite image applications and users. This paper performs attitude maneuver analysis by using Satellite Tool Kit(STK) made by AGI. In order to automate the STK analysis process, a MATLAB program is developed to generate STK input data and to process STK output data. Five attitude maneuver modes are analyzed and attitude angle variation and required torques are calculated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.2
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• pp.141-149
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• 2010

This paper contains impulsive maneuver which considers fuel consumption balance of chief satellite and deputy satellite in satellite formation flying. Thrust input is obtained by Lagrange' Multiplier method which is constructed by cost function with weight parameter of each satellite. Energy matching constraint is applied for boundedness of relative orbit, and theoretical solutions are verified by simulation results. Simulations are divided into two scenarios, with or without air-drag effect. This paper's results are expected to be used in real satellite formation flying, when fuel-balancing impulsive maneuver for relative orbit boundedness is needed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.9
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• pp.53-59
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• 2006

Need for agile satellite increases for performing various mission due to increase of satellite image applications and users. In high resolution satellite TDI (time delay and integration) method is adopted in order to improve SNR. But image quality can be degraded by satellite maneuver. In this paper requirements for remote sensing in high resolution satellite with agility are extracted and an approach to operate the agile satellite to perform the missions are proposed. The proposed approach in this paper will be applicable to system level design and analysis.

• Journal of Mechanical Science and Technology
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• v.19 no.9
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• pp.1695-1705
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• 2005

Reaction wheels and thrusters are commonly used for the satellite attitude control. Since satellites frequently need fast maneuvers, the minimum time maneuvers have been extensively studied. When the speed of attitude maneuver is restricted due to the wheel torque capacity of low level, the combinational use of wheel and thruster is considered. In this paper, minimum time optimal control performances with reaction wheels and thrusters are studied. We first identify the features of the maneuvers of the satellite with reaction wheels only. It is shown that the time-optimal maneuver for the satellite with four reaction wheels in a pyramid configuration occurs on the fashion of single axis rotation. Pseudo control logic for reaction wheels is successfully adopted for smooth and chattering-free time-optimal maneuvers. Secondly, two different thrusting logics for satellite time-optimal attitude maneuver are compared with each other: constant time-sharing thrusting logic and varying time-sharing thrusting logic. The newly suggested varying time-sharing thrusting logic is found to reduce the maneuvering time dramatically. Finally, the hybrid control with reaction wheels and thrusters are considered. The simulation results show that the simultaneous actuation of reaction wheels and thrusters with varying time-sharing logic reduces the maneuvering time enormously. Spacecraft model is Korea Multi-Purpose Satellite (KOMPSAT)-2 which is being developed in Korea as an agile maneuvering satellite.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.29-32
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• 1999

Korea Multi-Purpose SATellite(KOMPSAT) is scheduled to be launched by TAURUS launch vehicle in November, 1999. Tracking, Telemetry and Command(TT&C) operation and the flight dynamics support should be performed for the successful Launch and Early Orbit Phase(LEOP) operation. After the first contact of the KOMPSAT spacecraft, initial orbit determination using ground based tracking data should be performed for the acquisition of the orbit. Although the KOMPSAT is planned to be directly inserted into the Sun- synchronous orbit of 685 km altitude, the orbit maneuvers are required fur the correction of the launch vehicle dispersion. Flight dynamics support such as orbit determination and maneuver planning will be performed by using KOMPSAT Mission Analysis and Planning Subsystem(MAPS) in KOMPSAT Mission Control Element(MCE). The KOMPSAT MAPS have been jointly developed by Electronics and Telecommunications Research Institute(ETRI) and Hyundai Space & Aircraft Company(HYSA). The KOMPSAT MCE was installed in Korea Aerospace Research Institute(KARI) site for the KOMPSAT operation. In this paper, the orbit determination and maneuver planning are introduced and simulated for the KOMPSAT spacecraft in LEOP operation. Initial orbit determination using short arc tracking data and definitive orbit determination using multiple passes tracking data are performed. Orbit maneuvers for the altitude correction and inclination correction are planned for achieving the final mission orbit of the KOMPSAT.

• Transactions on Control, Automation and Systems Engineering
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• v.3 no.3
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• pp.196-202
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• 2001

Quick evaluations of two in-plane orbit maneuvers using small sets of real-time GPS navigation solutions were performed for the KOMPSAT-1 spacecraft operation. Real-time GPS navigation solutions of the KOMPSAT-1 were collected during the Korean Ground Station(KGS) pass. Only a few sets of position and velocity data after completion of the thruster firing were used for the quick maneuver evaluations. The results were used for antenna pointing data predictions for the next station contact. Normal orbit maneuver evaluations using large sets of playback GPS navigation solutions were also performed and the result were compared with the quick evaluation results.