• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.2
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• pp.33-39
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• 2013

Multilateration(MLAT) may complement secondary surveillance radar and also act as a real-time backup for the ADS-B system. This System is using time difference of arrival (TDOA) and based on triangulation principle. Each TDOA measurement defines a hyperbola describing possible aircraft locations. The accuracy in MLAT system depends on the positional relationship of the receiver and aircraft. There are various algorithms to localize aircraft based on TOA estimation. In this paper, we use least square method and extended Kalman filter and compare their results. Study results show that the extend Kalman filter provides a better performance than the least square method.

• 한국지형공간정보학회:학술대회논문집
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• 2004.10a
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• pp.67-72
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• 2004

21세기 지식정보화 사회를 당면하면서 정치, 경제, 문화 등의 환경이 다양한 형태로 급속히 변하고 있다. 다양한 형태의 정보를 적절한 기술을 이용하여 보다 효율적으로 수집하고 이를 신속하고 정확하게 분석하여 합리적인 의사결정을 하여야 하는데 사회변화의 속도가 급변함에 따라 당면한 문제들의 해결과 미래의 정보 수요에 부응하기 위한 핵심 기술로서 GIS는 정보화시대에서 무엇보다 정보시스템의 구축을 위한 계획 수립이 절실하게 되었다. 이러한 지리정보시스템에 동영상데이터의 연계기능을 더하여 영상을 기반으로 직접 사용자와 상호작용을 하며 데이터를 분석, 관리, 출력하는 동영상지리정보시스템(Video Geographic Information System: Video GIS)이 GIS 분야에 있어 새로운 연구 분야로 떠오르고 있다. 본 연구에서는 사회변화의 속도가 급변하는 도시기반시설물들을 효율적으로 개발, 관리하고 비행선촬영시스템을 통하여 취득된 동영상 자료를 객체추적 알고리즘에 의해 데이터의 양을 줄였다. 수치지도와 동영상데이터의 공간정보를 연계시켜 도시지역에 존재하는 각종 시설물을 관리할 수 있는 동영상 정보시스템을 Prototype으로 구축하여 그 가능성을 제시하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.217-221
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• 2007

In this study, forced vibrations analysis was performed for main wing of small scale WIG vehicle which is equipped two-stroke pusher type propeller engine, in terms of structural. for the frequency response analysis, excitations were assumed by H-mode(Horizontal mode), X-mode(Twisted mode) which is main vibration mode of engine, and for the transient response analysis, excitations were assumed by L-mode(Longitudinal mode) with propeller thrust which is occurred when it revolution.

• Journal of Aerospace System Engineering
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• v.4 no.1
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• pp.15-18
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• 2010

In the hot summer manual spray work for plants would be the hardest one among the agricultural field works. Besides the physical load the possible toxication would strongly ask a way to do the job on behalf of human. Although an aircraft with sprayer could be a good candidate, the manned airplanes do not play proper roles in our country because of field geometry. Today, unmanned helicopter as expensive as 200,000 dollars can do the job with high risk of control. Therefore safe and cheap air vehicle with sprayer, if developed, could be a great help to agriculture.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.125-131
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• 2004

최근 급속한 도시화와 국토개발에 의해 대규모의 사회기반시설이 확충되면서 각종 재해와 환경오염이 우리의 생활환경을 위협하고 있다. 따라서 체계적이고 효율적으로 시설물을 관리하기 위한 핵심기술로서의 GIS는 정보화시대에서 그 활용성이 높이 평가되고 있다. 이러한 지리 정보시스템에 비디오 데이터 연계 기능을 더하여 영상을 기반으로 직접 사용자와 상호작용을 하며 공간 데이터를 분석, 관리, 출력하는 비디오 지리 정보 시스템(Video Geographic Information System: Video GIS)이 GIS 분야에 있어서 새로운 연구 분야로 떠오르고 있다. 본 연구에서는 급변하는 도시지역의 시설물들을 실시간적으로 관리를 하기 위해 비행선촬영시스템을 통하여 취득된 비디오 자료를 데이터베이스화하고 이를 공간정보와 연계시켜 도시지역에 존재하는 각종 시설물을 관리할 수 있는 동영상 정보시스템을 prototype으로 구축하여 그 가능성을 제시하였다.

• Journal of Satellite, Information and Communications
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• v.1 no.2
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• pp.16-24
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• 2006

As a multi-mission GEO satellite, COMS system is being developed jointly by KARI, ETRI, KORDI, KMA, and industries from both abroad and domestic. EADS ASRTIUM is the prime contractor for manufacturing the COMS. ETRI is developing the COMS Ka-band payload and SGCS with the fund from MIC. COMS Satellite Ground Control System (SGCS) will be the only system for monitor and control of the satellite in orbit. In order to fulfill the mission operations of the three payloads and spacecraft bus, COMS SGCS performs telemetry reception and processing, satellite tracking and ranging, command generation and transmission, satellite mission planning, flight dynamics operations, and satellite simulation, By the proper functional allocations, COMS SGCS is divided into five subsystems such as TTC, ROS, MPS, FDS, and CSS. In this paper, functional design of the COMS SGCS is described as five subsystems and the interfaces among the subsystems.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.183-188
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• 2003

The present work was conducted to build a propulsion system for an airship. For this purpose, free shaft gas-turbine was modified to produce electrical power. he experiments were carried out to analyze the driving rotor condition at various power shaft loads. From this analysis, an appropriate damping device was required, and the changeable inertial moment from the fly-wheel was applied. Without the appropriate damping device, instability was found, and it was resulted as power loss. Also the amount of inertial moment was certified by the performance of dynamic transient effects from the engine test results. Knowledge gained from this research could benefit the propulsion and power conversion community by increasing the better understanding of shaft loads and inertial effects.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8B
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• pp.819-825
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• 2002

Resolution 221 requests the ITU-R to conduct studies, as a matter of urgency, on the feasibility of utilizing HAPS system as a base station to provide IMT-2000 services. And HAPS base stations should not cause harmful interference to the cellular IMT-2000 services. To study on the interference between HAPS system and cellular system is divided into two cases. One is the interference into HAPS system from the cellular system and the other is the interference into the cellular system from HAPS system. Since the former case has been already studied[1]. this paper describes the interference the interference to the noise power ration(I/N) with various parameters, such as the transmitting power, the number of users per cell, maximum antenna gain and the multibeam cell radius of HAPS. With the proposed estimation, we can determine the optimum values of various parameters in HAPS IMT-2000 system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.3
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• pp.274-280
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• 2016

Hinge driving type holding and release mechanism based on the burn wire release for application of cubesat is main payload of STEP Cube Lab. (Cube Laboratory for Space Technology Experimental Project) to be launched at 2015. It has high constraint force, low shock level as well as surmounting drawbacks of conventional nichrome burn wire release method that has relatively low constraint force and system complexity for application of multi-deployable systems. In this paper, we have proposed a flight model of holding and release mechanism for the verification of the constraint force and deployment status signal acquisition. To validate the effectiveness of the flight model, launch and on-orbit environment verification test have been performed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7B
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• pp.719-726
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• 2002

In WRC-2000, Resolution 734 was adopted to study the use of high altitude platform station(HAPS) operating in the bands above 30GHz. Therefore, frequency sharing feasibility between a new HAPS systems and an existing terrestrial fixed-service(FS) system should be analyzed primarily. In this paper, interference effects from the HAPS system into the radio-relay station are analyzed in terms of two cases; one is the interference distribution from the power-flux density(PFD) of HAPS airships, and the other the interference power from the ground stations. In conclusion, the new PFD criteria different from the exiting satellite system should be required, and the coordinated distance between the HAPS nadir and the radio-relay station should be 60km ∼ 253km for P$\sub$HG/ = -50dBW/MHz of transmitting power spectral density to share the new HAPS system into the existing FS system.