• Journal of Astronomy and Space Sciences
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• v.15 no.2
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• pp.427-436
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• 1998

The apogee manoeuvre of $KOREASAT-1{cdot}2{cdot}3$ is basic elliptical orbit transfer converting orbit plane. The KOREASAT-3 is planed for multi-burn manoeuvres using the liquid apogee engine while the $KOREASAT-1{cdot}2$ used the apogee kick motor that executes a single burn in the apogee of transfer orbit using the solid propellant. This study analyzed the multi-burn manoeuvres using the liquid apogee engine and the propellant control method and developed the simulation tools. For the purpose of precise simulation, We designed tools in the basic of orbit propagation software, COWELL5, that was developed by members of Center for Astrodynamics in Yonsei university and the results can be displayed in 3-D graphic of $STK/VO^{TM}$.

• Current Industrial and Technological Trends in Aerospace
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• v.8 no.2
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• pp.31-38
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• 2010

Environment and climate changes affect all aspects of our society. The enhanced remote sensing technology made the satellite to be widely used in the environment monitoring applications. Geostationary environmental monitoring is also actively researched due to the increased needs for the monitoring of diurnal environmental changes, troposhperic pollution and its origin. In this paper, recent development trends of geostationary environment monitoring payloads are introduced. GEO-CAFE and GIFTS missions are researched by the leading of the NASA and Sentinel-4 by the ESA. Those missions are in the state of detailed conceptual design and hardware development preparing with the launch plan in the late 2010s. By considering these development trends, domestic environment monitoring payloads shall be developed with careful analysis on the mission and data application.

• Environmental engineer
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• s.325
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• pp.15-15
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• 2013

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.267-271
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• 2004

The satellite in the geostationary orbit rotates around Earth center with the same angular rate as the Earth. So, the Earth can be observed with sequential time series. GOES(Geostationary Operational Environmental Satellites)-9 is a meteorological satellite, which is now located at 155ㆁE geostationary orbit location in order to monitor East-Asia meteorological environment including Korean Peninsular. Every meteorological information is acquired from GOES-9 with the period of about 1 hour. COMS(Communication, Ocean and Meteorological Satellite) has been developed by KARI(Korea Aerospace Research Institute) since 2003 and will be launched at 2008. COMS will be located at different orbit location compared to GOES-9. In this study, a simulated COMS image which is the perspective from different geostationary orbit location is generated using an GOES-9 image.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.3
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• pp.335-342
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• 2014

In this paper We study on test methods and procedures for Hybrid Track Circuit's practicalization. It's possible to apply to HTC's Seoulmetro and high-speed train by proposing test method considering special rail environment and RFID tag and leader, antenna We also present the test methods and procedures for safe and reliable of interface among the Hybrid track circuit devices.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.9
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• pp.914-924
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• 2010

In this paper, results on the orbit analysis for the KOMPSAT-2 satellite using a real orbit data during the LEOP and normal mission lifetime are presented. In particular, the preparation and performance of an orbit operations during the LEOP is emphasized and the effects of space environments (i.e., Solar activity) on orbit evolutions are investigated comparing to those of the KOMPSAT-1 satellite. The summarized results in this paper would be an important reference to improve the stability and effectiveness of satellite operations during the LEOP and normal mission lifetime in case of LEO satellites such as successors of KOMPSAT-2 (i.e., KOMPSAT-3, KOMPSAT-3A, KOMPSAT-5).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.895-904
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• 2008

CWR (Continuous Welded Rail) may be broken when a temperature drop below the neutral temperature changes in axial force, causing tensile fracture and rail gap, in winter. Rail-breaks may lead to the damage of the rail and wheel by dynamic load, and the reduction of running safety if not detected before the passage of a train. In this study, the track and train coupled model with open gap for dynamic interaction analysis, is proposed. Linear track and train systems is coupled by the nonlinear Herzian contact spring and the complete system matrices of total track-train system is constructed. And the interaction phenomenon considering open gap, was defined by assigning the irregularity functions between the two sides of a gap. Time history analysis, which have an iteration scheme such as $Newmark-{\beta}$ method based on Modified Newton-Raphson methods, was performed to solve the nonlinear equation. Finally, numerical studies are performed to assess the effect of various parameters of system, apply to various speeds, open gap size and the support stiffness of rail.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.6
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• pp.339-346
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• 2018

An Industry Foundation Classes(IFC), which is a data schema developed focusing on architecture, is being expanded to civil engineering structures. However, it is difficult to create an information model based on extended IFC since the BIM software cannot provide support functions. To manage a railway track based on the extended IFC, this paper proposed a method to create an alignment-centered separated railway track model and convert it to an extended IFC-based information model. First, railway track elements have been classified into continuous and discontinuous structures. The continuous structures were created by an alignment-based software, and discontinuous structures were created as independent objects through linkage of the discretized alignment. Second, a classification system and extended IFC schema for railway track have been proposed. Finally, the semantic information was identified by using the property of classification code and user interface. The availability of the methods was verified by developing an extended IFC-based information model of the Osong railway site.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.7
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• pp.629-635
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• 2012

This paper presents a performance analysis of the GPS(Global Positioning System) receiver on board in LEO satellites, based on the comparison of its in-orbit performances and corresponding ground test results. An extensive ground tests on the subject GPS receiver has been performed in diverse conditions under the right frame of ground test environments and the analysis of in-orbit performances has also been performed with the huge amount of accumulated GPS data which has been in operation for 6 years since its launch on 2006. For this analysis, we chose three sets of in-orbit data; the data during the early mission period, the data at the 3-year mission completion time, and the most recent in-orbit data. As the performance measures, we selected the position and time synchronization accuracy, and the comparative analysis shows the concurrency between the in-orbit performances and the ground test results with in these performance measures, verifying the validity of the ground test. It is expected that the test configuration and analysis method presented in this paper can be applied to developing and verifying the future Koreanized satellite GPS receivers.

• Journal of Aerospace System Engineering
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• v.15 no.5
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• pp.89-97
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• 2021

STEP Cube Lab-II (Cube Laboratory for Space Technology Experimental Project-II) is a 6U Cube satellite equipped with optical and infrared cameras for monitoring Mt. Paektu volcanic eruption signs and earth observation in the Korean peninsula. To guarantee successful mission operation of the cube satellite in orbit, thermal design is essential for the electronic equipment, and must be kept within the allowable temperature range during the mission period. Thus, it is necessary to analyze the predictable orbital thermal environment. The STEP Cube Lab-II is launched through the KSLV-II, however, the operation orbit has not been determined due to the unknown launch time. In this study, we performed a thermal analysis of the satellite and investigated the heat flux according to launch time to analyze the worst orbital conditions that could occur.