• Title/Summary/Keyword: Flight operations functions

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Implementation and Test of the Automatic Flight Dynamics Operations for Geostationary Satellite Mission

  • Park, Sang-Wook;Lee, Young-Ran;Lee, Byoung-Sun;Hwang, Yoo-La;Galilea, Javier Santiago Noguero
    • Journal of Astronomy and Space Sciences
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    • v.26 no.4
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    • pp.635-642
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    • 2009
  • This paper describes the Flight Dynamics Automation (FDA) system for COMS Flight Dynamics System (FDS) and its test result in terms of the performance of the automation jobs. FDA controls the flight dynamics functions such as orbit determination, orbit prediction, event prediction, and fuel accounting. The designed FDA is independent from the specific characteristics which are defined by spacecraft manufacturer or specific satellite missions. Therefore, FDA could easily links its autonomous job control functions to any satellite mission control system with some interface modification. By adding autonomous system along with flight dynamics system, it decreases the operator's tedious and repeated jobs but increase the usability and reliability of the system. Therefore, FDA is used to improve the completeness of whole mission control system's quality. The FDA is applied to the real flight dynamics system of a geostationary satellite, COMS and the experimental test is performed. The experimental result shows the stability and reliability of the mission control operations through the automatic job control.

Functional analysis of air transport mission (항공 수송 임무의 기능 분석에 관한 연구)

  • Song, Youn-Seob
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.16 no.4
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    • pp.41-48
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    • 2008
  • Functional analysis of air transport mission is conducted to establish the performance requirements of the commercial transport designs. The analysis process begins by making a top-down analysis to the aircraft system level mission functions. Correctly interpreting the top-level performance requirements is the first step in designing and building an aircraft system. Each function and sub-function is allocated and examined to the aircraft level and flight operations phase to optimize the system performance and design requirements, such that these lower-level requirements can be traced back to the top-level requirements they are designed to fulfill. Special attention is given to making sure all interfaces, both internal and external, are addressed. The results are also in good resources of functional hazard assessment involved in certification processes.

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Seat Allocation Model for Single Flight-leg using Linear Approximation Technique (선형근사 기법을 이용한 단일비행구간의 좌석할당 모형)

  • Song, Yoon-Sook;Lee, Hwi-Young
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2008.10a
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    • pp.65-75
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    • 2008
  • Over the last three decades, there are many researches focusing on the practice and theory of RM in airlines. Most of them have dealt with a seat assignment problem for maximizing the total revenue. In this study, we focus on a seat assignment problem in airlines. The seat assignment problem can be modeled as a stochastic programming model which is difficulty to solve optimally. However, with some assumptions on the demand distribution functions and a linear approximation technique, we can transform the complex stochastic programming model to a Linear Programming model. Some computational experiments are performed to evaluate out model with randomly generated data. They show that our model has a good performance comparing to existing models, and can be considered as a basis for further studies on improving existing seat assignment models.

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An Airline Scheduling Model and Solution Algorithms

  • AL-Sultan, Ahmed Thanyan;Ishioka, Fumio;Kurihara, Koji
    • Communications for Statistical Applications and Methods
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    • v.18 no.2
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    • pp.257-266
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    • 2011
  • The rapid development of airlines, has made airports busier and more complicated. The assignment of scheduled to available gates is a major issue for daily airline operations. We consider the over-constrained airport gate assignment problem(AGAP) where the number of flights exceeds the number of available gates, and where the objectives are to minimize the number of ungated flights and the total walking distance or connection times. The procedures used in this project are to create a mathematical model formulation to identify decision variables to identify, constraints and objective functions. In addition, we will consider in the AGAP the size of each gate in the terminal and also the towing process for the aircraft. We will use a greedy algorithm to solve the problem. The greedy algorithm minimizes ungated flights while providing initial feasible solutions that allow flexibility in seeking good solutions, especially in case when flight schedules are dense in time. Experiments conducts give good results.

Operational Validation of the COMS Satellite Ground Control System during the First Three Months of In-Orbit Test Operations (발사 후 3개월간의 궤도 내 시험을 통한 통신해양기상위성 관제시스템의 운용검증)

  • Lee, Byoung-Sun;Kim, In-Jun;Lee, Soo-Jeon;Hwang, Yoo-La;Jung, Won-Chan;Kim, Jae-Hoon;Kim, Hae-Yeon;Lee, Hoon-Hee;Lee, Sang-Cherl;Cho, Young-Min;Kim, Bang-Yeop
    • Journal of Satellite, Information and Communications
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    • v.6 no.1
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    • pp.37-44
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    • 2011
  • COMS(Chollian) satellite which was launched on June 26, 2010 has three payloads for Ka-band communications, geostationary ocean color imaging and meteorological imaging. In order to make efficient use of the geostationary satellite, a concept of mission operations has been considered from the beginning of the satellite ground control system development. COMS satellite mission operations are classified by daily, weekly, monthly, and seasonal operations. Daily satellite operations include mission planning, command planning and transmission, telemetry processing and analysis, ranging and orbit determination, ephemeris and event prediction, and wheel off-loading set point parameter calculation. As a weekly operation, North-South station keeping maneuver and East-West station keeping maneuver should be performed on Tuesday and Thursday, respectively. Spacecraft oscillator updating parameter should be calculated and uploaded once a month. Eclipse operations should be performed during a vernal equinox and autumnal equinox season. In this paper, operational validations of the major functions in COMS SGCS are presented for the first three month of in-orbit test operations. All of the major functions have been successfully verified and the COMS SGCS will be used for the mission operations of the COMS satellite for 7 years of mission life time and even more.

Design and Development of an Advanced Real-Time Satellite Simulator

  • Kang, Ja-Young;Kim, Jae-Moung;Chung, Seon-Jong
    • ETRI Journal
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    • v.17 no.3
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    • pp.1-16
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    • 1995
  • An advanced real-time satellite simulator (ARTSS) has been developed to support the ground operations activities of the ETRI satellite control system, such as testing of the system facilities, validation of flight control procedures, verification of satellite commands as well as training of the ground operators. The design of ARTSS is based on the top-down approach and makes use of a modular programming to ensure flexibility in modification and expansion of the system. Graphics-based monitoring and control facilities enhance the satellite simulation environment. The software spacecraft model in ARTSS simulates the characteristics of a geostationary communication satellite using a momentum bias three-axis stabilization control technique. The system can be also interfaced with a hardware payload subsystem such as Ku-band communication transponder to enhance the simulator capability. Therefore, ARTSS is a high fidelity satellite simulation tool that can be used on low-cost desk top computers. In this paper, we describe the design features, the simulation models and the real-time operating functions of the simulator.

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Seat Allocation Model for Single Flight-leg using Linear Approximation Technique (선형근사 기법을 이용한 단일비행구간의 좌석할당 모형)

  • Song, Yoon-Sook;Lee, Hwi-Young;Yoon, Moon-Gil
    • Korean Management Science Review
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    • v.26 no.3
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    • pp.117-131
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    • 2009
  • Over the last three decades, there are many researches focusing on the practice and theory of RM in airlines. Most of them have dealt with a seat assignment problem for maximizing the total revenue. In this study, we focus on a seat assignment problem in airlines. The seat assignment problem can be modeled as a stochastic programming model which is difficulty to solve optimally. However, with some assumptions on the demand distribution functions and a linear approximation technique, we can transform the complex stochastic programming model to a Linear Programming model. Some computational experiments are performed to evaluate out model with randomly generated data. They show that our model has a good performance comparing to existing models, and can be considered as a basis for further studies on improving existing seat assignment models.

System Engineering Interfaces of Reliability Engineering in Development of Launch Vehicle (우주발사체 개발사업에서 신뢰성공학의 시스템엔지니어링 인터페이스)

  • Shin, Myoung Ho;Cho, Sang Yeon;Joh, Miok
    • Journal of the Korean Society of Systems Engineering
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    • v.2 no.1
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    • pp.31-36
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    • 2006
  • Development of launch vehicle needs a large-scale and complicated System Engineering discipline interfacing to small-quantity production with special manufacturing processes. In general, the System Engineering discipline of launch vehicle has its relationship with Production, Operations, Product Assurance and Management disciplines and its internal partitions into the functions of System Engineering Integration & Control, Requirements Engineering, Analysis, Design and Configuration and Verification. As a function of Product Assurance, reliability of launch vehicle plays an significant role in risk management, system safety, flight safety and launch certification through design assurance. Moreover, major functions of systems engineering are integrated by means of reliability in the phases of design and verification. Therefore, derailed identification of system engineering interfaces of reliability, and execution of tasks for reliability assurance is required for successful development of launch vehicle. This paper identifies specific pattern and mechanism of the interfaces between reliability and system engineering.

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Development of RTEMS SMP Platform Based on XtratuM Virtualization Environment for Satellite Flight Software (위성비행소프트웨어를 위한 XtratuM 가상화 기반의 RTEMS SMP 플랫폼)

  • Kim, Sun-wook;Choi, Jong-Wook;Jeong, Jae-Yeop;Yoo, Bum-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.6
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    • pp.467-478
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    • 2020
  • Hypervisor virtualize hardware resources to utilize them more effectively. At the same time, hypervisor's characteristics of time and space partitioning improves reliability of flight software by reducing a complexity of the flight software. Korea Aerospace Research Institute chooses one of hypervisors for space, XtratuM, and examine its applicability to the flight software. XtratuM has strong points in performance improvement with high reliability. However, it does not support SMP. Therefore, it has limitation in using it with high performance applications including satellite altitude orbit control systems. This paper proposes RTEMS XM-SMP to support SMP with RTEMS, one of real time operating systems for space. Several components are added as hypercalls, and initialization processes are modified to use several processors with inter processors communication routines. In addition, all components related to processors are updated including context switch and interrupts. The effectiveness of the developed RTEMS XM-SMP is demonstrated with a GR740 board by executing SMP benchmark functions. Performance improvements are reviewed to check the effectiveness of SMP operations.

Evaluating High-Degree-and-Order Gravitational Harmonics and its Application to the State Predictions of a Lunar Orbiting Satellite

  • Song, Young-Joo;Kim, Bang-Yeop
    • Journal of Astronomy and Space Sciences
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    • v.32 no.3
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    • pp.247-256
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    • 2015
  • In this work, an efficient method with which to evaluate the high-degree-and-order gravitational harmonics of the non-sphericity of a central body is described and applied to state predictions of a lunar orbiter. Unlike the work of Song et al. (2010), which used a conventional computation method to process gravitational harmonic coefficients, the current work adapted a well-known recursion formula that directly uses fully normalized associated Legendre functions to compute the acceleration due to the non-sphericity of the moon. With the formulated algorithms, the states of a lunar orbiting satellite are predicted and its performance is validated in comparisons with solutions obtained from STK/Astrogator. The predicted differences in the orbital states between STK/Astrogator and the current work all remain at a position of less than 1 m with velocity accuracy levels of less than 1 mm/s, even with different orbital inclinations. The effectiveness of the current algorithm, in terms of both the computation time and the degree of accuracy degradation, is also shown in comparisons with results obtained from earlier work. It is expected that the proposed algorithm can be used as a foundation for the development of an operational flight dynamics subsystem for future lunar exploration missions by Korea. It can also be used to analyze missions which require very close operations to the moon.