• International Journal of Aeronautical and Space Sciences
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• 제2권2호
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• pp.95-107
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• 2001

This paper is devoted to the parameter optimization of unmanned aerial vehicle's (UAV) flight control laws. Optimization procedure is based on the ideas of mixed $H_2/H_{\infty}$ control of multi-model plants. By using this approach, some partial $H_2$-terms defining the performance of nominal and parametrically perturbed Flight Control System (FCS) responses to deterministic command signals in stochastic atmosphere as well as $H_{\infty}$-terms defining robustness of the FCS can be incorporated in the composite cost function. Special penalty function imposed on the location of closed-loop system's poles keeps the speed of response and oscillatory properties for both nominal and perturbed FCS in reasonable limits. That is the reason why this procedure may provide reasonable trade-off between the performance and robustness of FCS that are very important especially for UAV. Its practical importance is illustrated by case studies of lateral and longitudinal control of small UAV.

• 한국항행학회논문지
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• 제18권4호
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• pp.288-295
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• 2014

현재 사용 중인 계기착륙장치(ILS)는 시스템 특성상 동시에 다수의 입항하는 항공기가 사용하기 어렵고, 활주로 방향별로 장비들이 설치되어야 한다. 또한 착륙하는 항공기들이 일정한 구역에서 단일 비행경로만으로 착륙절차가 구성되어야 한다는 한계점이 있다. 이에 항공 교통량이 증가하게 된다면 입항하는 항공기들의 체공 시간이 더욱 증가하게 될 것이다. 이러한 한계점을 보완하기 위해 GNSS를 이용한 착륙시설로 GBAS가 개발 되었다. 본 논문에서는 비행시험 전 시뮬레이터를 이용하여 태안 비행장에서 실제 사용 하고 있는 항공기 착륙절차와 Curved approach를 이용한 절차를 비교 하였다. 비교 결과 Curved approach 절차를 이용하게 되면 기존절차보다 비행시간이 감소되어 연료 및 소음공역회피 등과 같은 효과가 일어 날 수 있을 것으로 판단된다.

• 한국항공운항학회지
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• 제23권2호
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• pp.51-56
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• 2015

This paper presents the procedure of drag prediction for EAV-1, based on a numerical analysis correlated to an in-flight test. EAV-1, developed by Korea Aerospace Research Institute, is a small-sized UAV to test a hydrogen-fuel cell power system. The long-endurance test flight of 4.5 hours provides numerous in-flight data. The thrust and drag of EAV-1 during the flight test are estimated based on the wind-tunnel test results for EAV-1's propeller performance. In addition, the CFD analysis using a commercial Navier-Stokes code is carried out for the full-scale EAV-1. The computational result suggests that the initial CFD analysis substantially under-predicts the in-flight drag in that the discrepancy is up to 27.6%. Therefore, additional investigation for more accurate drag prediction is performed; the effect of propeller slipstream is included in the CFD analysis through "fan disk" modelling. Also, the additional drag from airplane trim and load factor that actually exists during the flight test in a circular path is considered. These supplemental analyses for drag prediction turn out to be effective since the drag discrepancy reduces to 2.3%.

• 한국항공운항학회지
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• 제18권2호
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• pp.54-59
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• 2010

The flight deck crew must manage complexity during daily flight operations. The Airline may obtain data regarding threats and errors through LOSA(Line Operations Safety Audits) on normal flights as predictive safety tool in Safety Management System of the Airline to actively improve the systems such as SOP(Standard Operation Procedure), training, evaluation and the TEM(Threat and Error Management) for the flight deck crew. The flight deck crew make errors when they fail managing threats. The crew mismanage around ten percent of threats and commit errors. The major mismanaged threats are aircraft malfunction, ATC(Air Traffic Communication), and wether threats. The effective countermeasures of TEM for manageing threats are leadership, workload management, monitor & cross check, Vigilance, communication environment and cooperation of the crew. It is important that organizations must monitor for the hazards of threats and improve system for the safer TEM environments.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.171-174
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• 2007

The COMS flight software is implemented by ADA language and the high level application program language (APL). The APL is used to implement the Interpreted Program (IP) functions which are running on the processor. The IP functions have been developed for the payload management and monitoring with the automatic on-board operational procedure. The IP allows an easier re-programming if necessary. The ground can load or unload IP separately from ADA code in the RAM flight software. The uploaded IP is interpreted and executed by the Interpreted Program Environment (IPE) which is one of the functions implemented in the RAM flight software. In this paper, we introduce the IP and IPE function.

• 한국항공운항학회지
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• 제25권1호
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• pp.35-39
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• 2017

The engine is the most significant and essential part of the aircraft. As a result, systematical handling in the aircraft development stage is required from engine design to implementation to the full-scale airframe. This survey demonstrates the procedures demanded by the KAS 23 Civil Aircraft to acquire the engine Type Certification and the flight test procedures for ensuring the operational stability. Surveys were conducted on domestic and international aircraft engine certifications, technical regulations and documentations related to the Means of Compliance for flight test development stage. In addition, organized reference items that should be considered for the certification of engine flight test procedures were reviewed based on the KC-100.

• 한국항공우주학회지
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• 제41권8호
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• pp.657-664
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• 2013

상용 프로그램 MSC/NASTRAN의 FlightLoad를 사용하여 고세장비 유연날개 항공기의 하중해석을 수행하였다. 풍동시험 결과를 이용하여 공력모델을 보정하고, 항공기의 모든 기동조건을 묘사하기 위한 트림조건을 정립하였다. 또한 항공기 중량 모델링, 설계 임계조건 판단 및 해석용 하중카드 생성 등 모든 업무를 자동으로 생성할 수 있는 프로그램을 개발하였다. 이러한 기법과 프로그램을 이용하여 효율적인 항공기 개발을 위한 비행하중해석 절차를 수립하였다.

• 제어로봇시스템학회논문지
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• 제14권7호
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• pp.629-634
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• 2008

This paper presents the flight test procedure and the results for the airspeed indicator calibration of a light airplane the name of ChangGong-91, which is the first type certified aircraft from Korean Ministry of Construction and Transportation, as a part of the flight test validation to get the certification. The flight tests for airspeed position error calibrations are conducted using tower fly by method in order to calibrate swivel head testboom which is attached to the right wing tip of the airplane. Also system to system method is applied in order to calibrate the airspeed indicator of the cockpit. The flight test is conducted at the basis of the 'Korean Airworthiness Standard' which is the regulation of Korean Ministry of Construction and Transportation. The airspeed error range for the testboom and the airspeed indicator are determined to $-0.75{\sim}+0.75$ knot and to $-4.0{\sim}+2.0$ knots, respectively. The calibration results are applied to ChangGong-91 Flight Operation Manual.

• 품질경영학회지
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• 제49권3호
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• pp.255-268
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• 2021

Purpose: We sought to understand why a high-speed rotating projectile featuring a fuze-and-body assembly sometimes exhibited airburst, and we intended to improve the flight stability by eliminating airburst. Methods: We performed characteristic factor analysis, structural mechanics modeling, and dynamic modeling and simulation; and we scheduled firing tests to discover the cause of airburst. We used a step-by-step procedure to analyze the reliability function for selecting the bonding force standard that prevents airburst. Results: The 00MM high-speed rotating projectile features a fuze bonded to a body assembly; the bonding sometimes can break on firing. The resulting contact force, vibration and roll damping during flight generated yaw. Flight became unstable; fuze operation triggered an airburst. Our reliability test improved the bonding force standard (the force was increased). When the bonding force was at least the minimum required, a firing test revealed that airburst/flight instability disappeared. Conclusion: Analysis and identification of the causes of flight instability and airburst render military training safer and enhance combat power. Ammunition must perform as designed. Our method can be used to set standards that improve the performances of similar types of ammunition.

• Journal of Astronomy and Space Sciences
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• 제39권4호
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• pp.181-194
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• 2022

Korea Pathfinder Lunar Orbiter (KPLO), also known as Danuri, was successfully launched on 4 Aug. from Cape Canaveral Space Force Station using a Space-X Falcon-9 rocket. Flight dynamics (FD) operational readiness was one of the critical parts to be checked before the flight. To demonstrate FD software's readiness and enhance the operator's contingency response capabilities, KPLO FD specialists planned, organized, and conducted four simulations and two rehearsals before the KPLO launch. For the efficiency and integrity of FD simulation and rehearsal, different sets of blind test data were prepared, including the simulated tracking measurements that incorporated dynamical model errors, maneuver execution errors, and other errors associated with a tracking system. This paper presents the simulation and rehearsal results with lessons learned for the KPLO FD operational readiness checkout. As a result, every functionality of FD operation systems is firmly secured based on the operation procedure with an enhancement of contingency operational response capability. After conducting several simulations and rehearsals, KPLO FD specialists were much more confident in the flight teams' ability to overcome the challenges in a realistic flight and FD software's reliability in flying the KPLO. Moreover, the results of this work will provide numerous insights to the FD experts willing to prepare deep space flight operations.