• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.8
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• pp.807-815
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• 2008

In this paper, design, development and evaluation of DIP(Database Interface Program) are presented. The main purpose of this study is to improve the simulation quality to get more realistic response of target system. The designed and developed major function is composed of flexible memory structure, efficient arithmetic database language and high speed interpolation/extrapolation algorithm. To evaluate the operation speed and accuracy of returned data, trim simulation is performed based on in-house software and, DIP is applied to existing real-time simulator such as engineering HQS(Handling Quality Simulator) to evaluate reliability and performance. The result of evlaution reveals that calculation speed and data accuracy are satisfied, and flight performance is satisfied in the real-time simulator environments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.62-68
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• 2018

This study was conducted to improve the shooting stability of self propelled artillery by improving the flick rammer system. The flick rammer system is designed to reduce crew fatigue and shorten the movement and loading time of the shell compared with the conventional manual loading system. Basically, in the flick rammer system of the shooting type, fall-back occurs intermittently, which causes problems in the rapid loading. To solve this problem, a detailed C.A.E. (Computer Aided Engineering) analysis of the internal structure of the existing rapid loading field was conducted. Through this, we sought a solution that can prevent fall-back by reducing the flying distance. We then optimized the loading station to reduce the flying distance and confirmed the possibility of suppressing the fall-back compared to the existing product through actual tests in the field.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.6
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• pp.92-100
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• 2002

In this study, transonic/supersonic nonlinear flutter analysis system of a complete aircraft including forced harmonic motion pf control surfaces has been effectively developed using the modified transonic small disturbance (TSD) equation. To consider the nonlinear effects, the coupled time marching method (CTM) combining computational structural dynamics (CFD) has been directly applied for aeroelastic computations. The grid system for a complex full aircraft configuration is effectively generated by the developed inhouse code. Intransonic and supersonic flight regimes, the characteristics of static and dynamic aeroelastic effect has been investigated for a complete aircraft model. Also, nonlinear flutter flight simulations for the forced harmonic motion of control surfaces are practically presented in detail.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.475-478
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• 2006

본 논문에서는 소형 무인항공기의 정확한 위치, 속도, 자세 정보를 제공하기 위해 저급의 MEMS IMU를 이용한 항법 시스템을 제안한다. 제안하는 시스템은 비행체의 직선운동과 회전운동을 측정할 수 있는 관성측정기와 위성신호를 수신하여 항체의 위치, 속도 정보를 제공하는 GPS 수신기, 지구 자기장 정보를 이용하여 방향각 정보를 제공하는 지자기 센서들로 구성되었다. SDINS와 약결합 방식의 칼만필터를 이용한 항법 시스템은 초기정렬 알고리즘과 센서 오차 보상 알고리즘, 자력계 보상 알고리즘 및 복합항법 알고리즘으로 나뉘며, 설계된 항법 알고리즘들은 시뮬레이션과 차량 실험을 통해서 성능을 분석하였다.

• Proceedings of the KAIS Fall Conference
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• 2007.11a
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• pp.222-225
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• 2007

본 논문에서는 항공기가 레이다 감시를 회피하고 미사일의 공격으로부터 효과적으로 대응하기 위한 채프의 RCS 계산 방법에 대해 다루었다. 공중에 투하된 채프의 RCS 값은 바람, 비행체의 속도, 대기확산 속도 등에 따라서 달라진다. 채프를 레이다 사용주파수 대역에서 다이폴 안테나로 가정하고, 다이폴 안테나의 산란특성 분석을 통하여 RCS 값을 예측하였다. 본 논문에서는 다이폴 모델로 계산한 채프의 RCS값을 CST-MWS를 이용하여 계산 하였으며 기존에 소개된 실험값들과 비교하여 유사한 특성을 얻었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.199-202
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• 2008

The advantage of ultrasonic burning rate measurement of solid propellant is measuring burning rates with wide range of pressure in a single test. In the ultrasonic method, instantaneous thickness of solid propellants as function of pressure or time were measured using time of flight(TOF) of ultrasonic signals. So, uncertainties of the measured burning rates by ultrasonic method have to evaluate with variation of pressure, TOF and initial propellant thickness. In this study, we evaluated uncertainties of ultrasonic method for measuring burning rates on the types 317 and the 318 propellants.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.6
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• pp.401-410
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• 2020

In this study, a real-time Tactical UAS position compensation system based on image information developed to compensate for the weakness of location navigation information during GPS signal interference and jamming / spoofing attack is described. The Tactical UAS (KUS-FT) is capable of automatic flight by switching the mode from GPS/INS integrated navigation to DR/AHRS when GPS signal is lost. However, in the case of location navigation, errors accumulate over time due to dead reckoning (DR) using airspeed and azimuth which causes problems such as UAS positioning and data link antenna tracking. To minimize the accumulation of position error, based on the target data of specific region through image sensor, we developed a system that calculates the position using the UAS attitude, EO/IR (Electric Optic/Infra-Red) azimuth and elevation and numerical map data and corrects the calculated position in real-time. In addition, function and performance of the image information based real-time UAS position compensation system has been verified by ground test using GPS simulator and flight test in DR mode.

• 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 Advanced Navigation Technology
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• v.3 no.2
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• pp.139-146
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• 1999

A flight simulator is composed of engine, navigation systems and instrument modules. However, two problems exist here. First, the coordinate of each independent module is not same. To solve this problem, we design a method that mutual coordinates are capable of transformation each other. Second, the distance and bearing between two points on the earth are computed in a sphere shape using the spherical trigonometry. However, the computing time is very severe. In this paper, we project the sphere into the planar to reduce the computing time. An experimental result shows that the performance of the proposed method is excellent to both distance and bearing calculations in close region. Also, the computing time is reduced from $4.95{\times}10^{-4}$ seconds to $1.648{\times}10^{-4}$ seconds.