• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.6
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• pp.741-747
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• 2009

For construction of 3D virtual city models, airborne digital cameras, laser scanners, multi-oblique photograph systems and other devices are currently being used. With such advanced techniques, precise 3D spatial information can be collected and high quality 3D city models can be built in a considerably large area. The 3D spatial information to be built has to provide the latest information that quickly reflects the causes of any change due to urban development. In this study, a UAV photogrammetric method using low cost UAV and digital camera was proposed to acquire and update 3D spatial information effectively on small areas where information continuously change. In the proposed UAV photogrammetric method, the elements of interior orientation were acquired through camera calibration and the vertical and oblique photographs were taken at 9 points and the 3D drawing of ground control points and buildings was performed using 20 images among the pictured images. This study also analyzed the accuracy of the proposed method comparing with ground survey data and digital map in order to examine whether the method can be used in on-demand 3D spatial information update on relatively small areas.

• Journal of Aerospace System Engineering
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• v.16 no.1
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• pp.40-48
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• 2022

Recent studies have reported about UAV-based disaster rescue system adopting AR technology. Performing a disaster rescue training in an environment similar to an actual disaster site results in high costs and risk of accidents. In this paper, we propose a simulation software using VR technology so that rescuer can safely and inexpensively train the operation of the disaster rescue system. Through the analysis of the existing system, we derived the requirements for virtualizing training, and developed the simulation software using Unreal Engine and Airsim API. Simulation results show that the proposed simulation software can effectively simulate the operation of the conventional disaster rescue system.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.2
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• pp.173-178
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• 2007

Recently, fires happen to occur owing to various factors. However, the demage caused by the fire is eyer increasing because timely actions could not be taken. To reduce the demage, a development of fire detection system which makes it possible to take adequate actions is requited. In this work, a sensor network-based fire detection system which utilizes both sensor nodes equipped with smoke sensor and unmaned helicopter is proposed. The proposed system is composed of unmaned helicopter which can gather the measurement data from the deployed sensor nodes and the embedded system which can get visual information on the firing spot and transmit these images to a remote server computer. The proposed system is applied to actual test bed to verify its feasibility.

• Journal of Aerospace System Engineering
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• v.16 no.1
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• pp.81-85
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• 2022

In this study, we conducted a structural design and analysis of air intake of aircraft engine using composite materials. First, an investigation on structural design requirement of target structure was carried out. The distributed pressure load and acceleration condition was applied to structural design. To evaluate the structural design result, finite element analysis was carried out. The stress, deflection and buckling analysis for structural safety evaluation was performed. Finally, it was confirmed that the air intake through structural analysis is safety.

• 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 for Aeronautical & Space Sciences
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• v.36 no.5
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• pp.448-454
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• 2008

This paper deals with a behavior based decentralized control strategy for UAV swarming utilizing the artificial potential functions and the sliding mode control technique. Individual interactions for swarming behavior are modeled using the artificial potential functions. The motion of individual UAV is directed toward the negative gradient of the combined potential. For tracking the reference trajectory of UAV swarming, a swarming center is considered as the object of control. The sliding-mode control technique is adopted to make the proposed swarm control strategy robust with respect to the system uncertainties and the varying mission environment. Numerical simulation is performed to verify the performance of the proposed controller.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.11
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• pp.990-998
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• 2007

Adaptive output feedback control technique using Neural Networks(NN) is proposed for uncertain nonlinear Multi-Input Multi-Output(MIMO) systems. Modified Dynamic Inversion Model(MDIM) is introduced to decouple uncertain nonlinearities from inversion-based control input. MDIM consists of approximated dynamic inversion model and inversion model error. One NN is applied to compensate the MDIM of the system. The output of the NN augments the tracking controller which is based upon a filtered error approximation with online weight adaptation laws which are derived from Lyapunov's direct method to guarantee tracking performance and ultimate boundedness. Several numerical results are illustrated in the simulation of Van der Pol system and unmanned helicopter with model uncertainties.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.5
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• pp.41-47
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• 2002

In this paper, a guidance law applicable to aircraft automatic landing is proposed and its performance is compared with the conventional ILS-type landing approach. The concept of miss distance, which is commonly used in the missile guidance laws, and Lyapunov stability are effectively combined to obtain the landing guidance law. The new landing guidance law is integrated into the existing controller and is applied to the landing approach and flare phases of landing procedure. Numerical simulation results show that the new landing guidance law is a viable alternative to the conventional strategies that directly control the longitudinal deviation or altitude.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.4
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• pp.117-124
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• 2015

RAM (Reliability, Availability and Maintenance) has been applied to design and analysis tools which affects system's operational sustainability and its life cycle cost as RAM-c(2009 DoD). RAM-c plays also an important role to guarantee the system engineering for mission assurance. Reliability is highly related to the probability of system failure. Availability means mission capability or the condition of ready to mission. Maintenance includes both the repair to recover the system in the event of failure/unexpected breakdown and proactive maintenance to prolong the design service life of the system or machinery. It is the purpose that this paper is to analyze and conclude the objective service life of UAV. The more UAV is operated, the less the level of its reliability becomes. Repairing failures and supplying spare parts on time, system reliability could be improved up until the time over target. Applying statistical Weibull distributions, this paper suggests the analysis of the design service life and economic life of UAV based on RAM-c with operational data.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.4
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• pp.65-74
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• 2014

Unmanned aerial vehicles(UAVs) refer to the aircraft which carries no human pilot and is operated under remote control or in autonomous operational mode. As the UAVs can perform the dull, dangerous and difficult missions, various kinds of UAVs with different sizes and weights have been developed and operated for both civil and military application. As the avionics and communication technology related to the UAVs are matured, the demand for the UAVs is dramatically increased. Therefore, It is important to develope airworthiness process and regulations of the UAVs to minimize related risk to the man and environment. This paper describes related regulations and classification of the small UAVs for different international airworthiness authorities. The analysis of the CS-LURS verses Stanag 4702 and Stanag 4703 can provide guidelines for the generation of the airworthiness certification criteria for the small UAVs in civil sector. This paper conducted kinetic impact energy analysis of the loss of the small UAVs control scenarios and of the very small UAVs under 66 joules. Based on the analysis, the energy impact analysis can be considered before the design certification approval for the small UAVs.