• Electronics and Telecommunications Trends
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• v.37 no.1
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• pp.10-20
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• 2022

A drone without attaching guns or bombs can be a dangerous weapon, since its motor speed is greater than 3000 rpm, which is similar to that of a mower powered by a LiPo battery. The anti-drone system is the only means of detecting and neutralizing drone attacks. Many defense companies around the world provide solutions using various types of equipment (for example, radar, cameras, jamming guns, and net guns). ETRI has also developed a Low-Altitude Drone Detection (LADD) system consisting of Ku-band radar and an Electro-Optical/Infra-Red (EO/IR) camera. In this paper, we summarize recent technical advances in anti-drone systems around the world and introduce the features and describe the performance of the LADD system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.10
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• pp.1012-1019
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• 2010

In this paper, The flight data processing system was designed for multiple target flight test. For flight data processing, multiple target grouping, data fusion processing, and data slaving processing were performed and, as a data fusion filter, centralized, and federated Kalman filters were designed. A centralized kalman filter was modified in order to improve the vehicle's low altitude measurement using radar's SNR and estimation process. From the testing of multiple target missile, it confirmed flight trajectory measurement was improved in low altitude area and the beginning stage of vehicle.

• Composites Research
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• v.14 no.2
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• pp.50-59
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• 2001

The predictions of residual strength evolution and fatigue life of full scale composite rotor blade for multipurpose helicopter were studied using a strength degradation model. Flight-by-flight load spectrum was developed on the basis of FELIX standard spectrum data. The laminated structural analysis was also performed to obtain corresponding local stress and/or strain spectra for each ply of laminate skin and glass roving spar structures around the blade root where fatigue damage was severely anticipated.

• Annual Conference of KIPS
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• 2024.10a
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• pp.447-450
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• 2024

궤도상 서비싱(On-Orbit Servicing)이란, 우주 공간의 궤도에서 비행하는 인공 물체를 대상으로 상태를 점검 및 수리하거나 궤도 수정 또는 궤도 내 자세 유지, 연료 재급유, 부품 교체, 우주 쓰레기 제거 등을 제공하는 서비스이다. 이는 위성 수명 연장 및 재사용성 증대를 통한 인적, 시간적 비용절감 결과를 가져온다. 이러한 임무를 수행하기 위해서는 대상이 되는 객체를 안전하게 고정하고 유지하는 캡처 및 도킹 과정이 필요하며 데이터는 실시간 모니터링으로 감지한다. 이때, GNC(유도, 항법, 제어) 시스템의 프레임워크는 항공우주 분야에서 우주 비행체가 임무를 수행할 때 필수적인 기능을 통합하고 관리하며 수행하는 구조적 틀을 제공한다. 센서, 알고리즘, 제어기, 항법 장치 등 연관된 하드웨어와 소프트웨어가 유기적으로 작동하도록 구성되어 있으며 비행체가 목표를 정확히 수행하도록 돕는 핵심적인 역할을 한다. 본 논문에서는 기존 궤도상 서비싱의 해외 연구 현황을 파악하여 임무 사례를 통한 GNC 시스템 프레임워크의 분석을 토대로 추후 국내 궤도상 서비싱 GNC 서브시스템 프레임워크 설계 시 적용 방안에는 어떤 것이 있을지에 대하여 연구한 내용을 서술하고자 한다.

• Proceedings of the Korea Contents Association Conference
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• 2016.05a
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• pp.197-198
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• 2016

본 연구에서는 소형UAV중 쿼드콥터, 헥사콥터, 옥토콥터를 이용하여 문화재지정구역 현장에서 경로비행을 실제 운용함으로써 명승조사연구에 적용 가능한 소형UAV를 확인하고자 하였다.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.3
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• pp.77-81
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• 2012

In a cryogenic propellant tank the pressurant is contracted due to heat loss and the propellant itself evaporates. On a restartable propulsion system such phenomena are more intensive because the propellant contacts with the pressurant on the larger surface during the coast flight. Such heat and mass transfer phenomena should be considered for estimating the amount of pressurant. On the hypothesis that the heat and mass transfer quasi-equilibrium is achieved during the coast flight, the calculation process of the equilibrium pressure is presented. On the process the amount of loaded helium on the Falcon-1 second stage is calculated.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.201-205
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• 2011

In a cryogenic propellant tank the pressurant is contracted due to heat loss and the propellant itself evaporates. On a restartable propulsion system such phenomena are more intensive because the propellant contacts with the pressurant on the larger surface during the coast flight. Such heat and mass transfer phenomena should be considered for estimating the amount of pressurant. On the hypothesis that the heat and mass transfer quasi-equilibrium is achieved during the coast flight, the calculation process of the equilibrium pressure is presented. On the process the amount of loaded helium on the Falcon-1 second stage is calculated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.7
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• pp.35-44
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• 2006

When control surface failure occurs, it is conventional to correct a current control or to transform to other control. In this paper, instead of adopting a conventional way, a reconfiguration method which compensate the failure with alternative control surface deflection, depending on the level of failure, by using neural network and PCH(Pseudo-Control Hedging). The Conroller is designed of inner-loop(SCAS : Stability Command Augmentation System) with DMI(Dynamic Model Inversion) and outer-loop with Y axis acceleration feedback for a coordinate turn. Additionally, double PCH method was adopted to prevent actuator saturation and input command was generated to compensate for failure. At the end, The feasibility of the method is validated with randomly selected failure scenarios.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.1
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• pp.66-72
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• 2007

an approach to air-vehicle design, an application of the radio-controlled model flight test techniques has been presented. The approach presented in this study is to validate the air-vehicle design configuration by analyzing the flight test results of scale model with dynamic similarities, and then to apply the analyzed results to the aerodynamic design process in early stage of the air-vehicle development. To develop practically applicable similarity laws for the subscale flying model design, the air-vehicle motions are decoupled into rotational motions for stability & control similarities and translational motions for flight performance similarities. Also, detail techniques for radio-controlled model flight test have been developed. Based on the results obtained from the radio-controlled flight test, the present approach for air-vehicle design has shown to be useful to validate the air-vehicle design configuration.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.12
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• pp.997-1010
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• 2021

This study collected and analyzed flight data of SpaceX's Falcon 9 launch vehicle. All missions were classified by orbital types, such as Polar, SSO, ISS, LEO and GTO missions. In characteristic maneuvers of main engine cutoff, boostback, reentry and landing burn at each stage of 1st stage launch vehicle, changes of the physical parameters like speed, altitude, dynamic pressure and acceleration were investigated. The guidelines derived from detailed maneuver analysis were suggested, which can be used as design and evaluation references for developing reusable launch vehicle.