• Journal of Astronomy and Space Sciences
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• 제20권3호
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• pp.227-238
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• 2003

Spacecraft mission planning functions including event prediction, mission scheduling, command planning, and ground track display have been developed for the KOMPSAT-2 mission operations. Integrated event prediction functions including satellite orbital events, user requested imaging events, and satellite operational events have been implemented. Mission scheduling functions have been realized to detect the mission conflicts considering the user specified constraints and resources, A conflict free mission scheduling result is mapped into the spacecraft command sequences in the command planning functions. The command sequences are directly linked to the spacecraft operations using eXtensible Markup Language(XML) for command transmission. Ground track display shows the satellite ground trace and mission activities on a digitized world map with zoom capability.

• 산업경영시스템학회지
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• 제39권1호
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• pp.56-63
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• 2016

We consider a satellite mission scheduling problem, which is a promising problem in recent satellite industry. This problem has various considerations such as customer importance, due date, limited capacity of energy and memory, distance of the location of each mission, etc. Also we consider the objective of each satellite such as general purpose satellite, strategic mission and commercial satellite. And this problem can be modelled as a general knapsack problem, which is famous NP-hard problem, if the objective is defined as to maximize the total mission score performed. To solve this kind of problem, heuristic algorithm such as taboo and genetic algorithm are applied and their performance are acceptable in some extent. To propose more efficient algorithm than previous research, we applied a particle swarm optimization algorithm, which is the most promising method in optimization problem recently in this research. Owing to limitation of current study in obtaining real information and several assumptions, we generated 200 satellite missions with required information for each mission. Based on generated information, we compared the results by our approach algorithm with those of CPLEX. This comparison shows that our proposed approach give us almost accurate results as just less than 3% error rate, and computation time is just a little to be applied to real problem. Also this algorithm has enough scalability by innate characteristic of PSO. We also applied it to mission scheduling problem of various class of satellite. The results are quite reasonable enough to conclude that our proposed algorithm may work in satellite mission scheduling problem.

• 한국항공우주학회지
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• 제36권12호
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• pp.1163-1170
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• 2008

본 논문에서는 위성 임무 스케줄링을 효율적으로 수행하기 위해 유전 알고리즘을 이용한 최적화 스케줄링 알고리즘을 개발하고, 시뮬레이션을 통해 검증한 결과를 기술하였다. 위성 임무 스케줄링은 위성에게 요구된 작업들과 그에 따른 제한사항 및 다양한 변수들을 종합적으로 고려하여 상호간의 시간, 조건 등의 충돌을 회피함과 동시에 위성의 자원을 최대한 활용하여 운용할 수 있는 최적의 작업시간표를 생성하는 것이다. 이러한 위성 임무 스케줄링은 요구되는 임무량이 많고, 제한조건들이 다양할수록 필수적이나, 스케줄링 기준 및 능률성은 위성의 운용목적에 따라 달라질 수 있다. 본 논문에서는 유전 알고리즘을 이용한 스케줄링 알고리즘을 운용목적이 다른 위성들에 대해 목적함수 내 가중치 조정 및 유전 알고리즘 연산자의 조합에 따라 적용한 결과를 비교, 검증하였으며, 결과적으로 다양한 위성의 스케줄링 문제에 응용할 수 있음을 증명하였다.

• 한국항공우주학회지
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• 제38권1호
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• pp.48-57
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• 2010

본 논문에서는 위성 임무 스케줄링을 효율적으로 수행하기 위한 스케줄링 최적화 알고리즘을 타부탐색 알고리즘과 유전 알고리즘을 이용해 디자인하고, 시뮬레이션을 수행한 비교 결과를 기술하였다. 위성 임무 스케줄링은 위성에게 요구된 작업들과 그에 따른 제한사항 및 다양한 변수들을 종합적으로 고려하여 상호간의 시간, 조건 등의 충돌을 회피함과 동시에 위성의 자원을 최대한 활용하여 운용할 수 있는 최적의 작업시간표를 생성하는 것이다. 위성 임무 스케줄링은 동시에 많은 변수를 고려해야 하기 때문에 연산양이 많고, 매 스케줄링 시 마다 동일한 과정을 반복적으로 수행해야 하므로, 스케줄링 최적화 알고리즘과 같은 위성 운영 자동화, 자율화가 요구되는 분야이다. 다양하게 이용되고 있는 두 가지 스케줄링 기법을 위성 임무 스케줄링 최적화에 적용해 보았다.

• 제어로봇시스템학회논문지
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• 제16권6호
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• pp.572-578
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• 2010

In this paper, the final fitness results of the satellite mission scheduling algorithm, which is designed by using the genetic algorithm, are simulated and compared with respect to the control constants. Heuristic algorithms, including the genetic algorithm, are good to find global optima, however, we have to find the optimal control constants before its application to a problem, because the algorithm is strongly effected by the control constants. In this research, the satellite mission scheduling algorithm is simulated with different crossover probability and mutation probability, which is major control constant of the genetic algorithm.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.228-231
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• 2006

In this paper, requirements of Meteorological Administration about Meteorological Imager (MI) of Communications, Ocean and Meteorological Satellite (COMS) is analyzed for the design of COMS ground station and according to the analysis results, the distribution image size of each observation area suitable for satellite Field Of View (FOV) stated at the requirements of meteorological administration is determined and the precise satellite FOV and the size of distribution image is calculated on the basis of the image size of the determined observation area. The results in this paper were applied to the detailed design for COMS ground station and also are expected to be used for the future observation scheduling and the scheduling of distribution of user data.

• International Journal of Aeronautical and Space Sciences
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• 제17권1호
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• pp.89-100
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• 2016

Given the unpredictability of the space environment, satellite communications are manually performed by exchanging telecommands and telemetry. Ground support for orbiting satellites is given only during limited periods of ground antenna visibility, which can result in conflicts when multiple satellites are present. This problem can be regarded as a scheduling problem of allocating antenna support (task) to limited visibility (resource). To mitigate unforeseen errors and costs associated with manual scheduling and mission planning, we propose a novel method based on a genetic algorithm to solve the ground support problem of multiple satellites and antennae with visibility conflicts. Numerous scheduling parameters, including user priority, emergency, profit, contact interval, support time, remaining resource, are considered to provide maximum benefit to users and real applications. The modeling and formulae are developed in accordance with the characteristics of satellite communication. To validate the proposed algorithm, 20 satellites and 3 ground antennae in the Korean peninsula are assumed and modeled using the satellite tool kit (STK). The proposed algorithm is applied to two operation modes: (i) telemetry, tracking, and command and (ii) payload. The results of the present study show near-optimal scheduling in both operation modes and demonstrate the applicability of the proposed algorithm to actual mission control systems.

• ETRI Journal
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• 제25권5호
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• pp.387-400
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• 2003

Since its launching on 21 December 1999, the Korea Multi-Purpose Satellite-I (KOMPSAT-I) has been successfully operated by the Mission Control Element (MCE), which was developed by the ETRI. Most of the major functions of the MCE have been successfully demonstrated and verified during the three years of the mission life of the satellite. This paper presents the operational performances of the various functions in MAPS. We show the performance and analysis of orbit determinations using ground-based tracking data and GPS navigation solutions. We present four instances of the orbit maneuvers that guided the spacecraft form injection orbit into the nominal on-orbit. We include the ground-based attitude determination using telemetry data and the attitude maneuvers for imaging mission. The event prediction, mission scheduling, and command planning functions in MAPS subsequently generate the spacecraft mission operations and command plan. The fuel accounting and the realtime ground track display also support the spacecraft mission operations.

• ETRI Journal
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• 제30권1호
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• pp.1-12
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• 2008

In this paper, we propose an efficient single-resource task scheduling algorithm for the Communication, Ocean, and Meteorological Satellite. Among general satellite planning functions such as constraint check, priority check, and task scheduling, this paper focuses on the task scheduling algorithm, which resolves conflict among tasks which have an exclusion relation and the same priority. The goal of the proposed task scheduling algorithm is to maximize the number of tasks that can be scheduled. The rationale of the algorithm is that a discarded task can be scheduled instead of a previously selected one depending on the expected benefit acquired by doing so. The evaluation results show that the proposed algorithm enhances the number of tasks that can be scheduled considerably.

• 한국위성정보통신학회논문지
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• 제3권2호
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• pp.26-31
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• 2008

As a multi-mission GEO satellite, Communication, Ocean, and Meteorological Satellite (COMS) is scheduled to be launched in the year 2009. COMS has three different payloads: Ka-band communication payload, Geostationary Ocean Color Imager (GOCI) and Meteorological Imager (MI). Among the three payloads, MI and GOCI have several conflict relationships; one of them is that if MI mirror moves vertically larger than 4 Line Of Sight (LOS) angle while GOCI is imaging, image quality of GOCI becomes degraded. In this paper, MI scheduling algorithm to prevent GOCI's image quality degradation will be presented.