• 한국항공운항학회지
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• 제30권1호
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• pp.1-11
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• 2022

The capacity of Jeju International Airport has reached its limit due to a surge in air traffic demand such as passengers and cargo and the continuous expansion of Low Cost Carriers (LCC). Despite COVID-19 that has began in November 2019, Jeju International Airport still has continuous demand in terms of passenger and cargo transportation. As a result, it is undeniable that the delay rate also unexpectedly increased as the air traffic volume at Jeju International Airport continued to increase. In this study, the correlation between Turnaround Time and delay rates of national airlines is analyzed based on past flight data at Jeju International Airport, and the cumulative delay time trend for sampled airlines is compared with Turnaround Time. Through this study, it is expected to contribute to securing aircraft operation efficiency and on-time by analyzing delays related to Turnaround Time at Jeju International Airport.

• International Journal of Aeronautical and Space Sciences
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• 제17권1호
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• pp.54-63
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• 2016

A novel attitude tacking control method using Time Delay Control (TDC) scheme is developed to provide robust controllability of a rigid hexacopter in case of single or multiple rotor faults. When the TDC scheme is developed, the rotor faults such as the abrupt and/or incipient rotor faults are considered as model uncertainties. The kinematics, modeling of rigid dynamics of hexacopter, and design of stability and controllability augmentation system (SCAS) are addressed rigorously in this paper. In order to compare the developed control scheme to a conventional control method, a nonlinear numerical simulation has been performed and the attitude tracking performance has been compared between the two methods considering the single and multiple rotor faults cases. The developed control scheme shows superior stability and robust controllability of a hexacopter that is subjected to one or multiple rotor faults and external disturbance, i.e., wind shear, gust, and turbulence.

• 한국항공운항학회지
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• 제21권1호
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• pp.15-22
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• 2013

In oceanic flight routes, HF radio and satellite data links have weather restrictions, long propagation delay and low data throughput. In this paper, we propose oceanic aeronautical communications scheme in the VHF band based on ad-hoc communication. The proposed scheme organizes autonomously a multi-hop network that is divided into multiple local network using aircraft to fly long-distance communication and supports a hybrid type of multiple access, which consists of random access and TDMA (Time Division Multiple Access) scheme. In addition, several algorithms to apply spatial reuse of transmission to multi-hop long range communication environments have been proposed. The proposed system proves performance improvement on delay time as an effective solution to communicate end-to-end on the oceanic flight routes and strengthens the reliability of oceanic aeronautical communication.

• 항공우주시스템공학회지
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• 제18권1호
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• pp.29-36
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• 2024

최근 도심항공모빌리티(Urban Air Moility, UAM)의 개념이 미래항공모빌리티(Advanced Air Mobility, AAM)으로 확장되면서 틸트로터형 수직 이착륙기에 관한 연구개발이 활발하다. 틸트로터의 경우 수직비행과 수평비행 사이에 천이비행을 하게 되는데 천이비행 구간의 비행 안정성을 확보하기 위해 블레이드 피치각 제어시스템을 활용할 수 있다. 또한 개별 블레이드 제어(Individual Blade Control, IBC)를 통하여 천이비행 구간 동안 발생하는 소음 및 진동을 감소시킬 수 있다. 본 논문에서는 전기-기계식 구동기 기반 블레이드 피치각 제어시스템의 개별 블레이드 제어를 위한 외란 관측기와 시간 지연제어기를 설계하고 수치 시뮬레이션을 통해 설계한 제어기들의 성능을 비교분석한다.

• 대한임베디드공학회논문지
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• 제11권1호
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• pp.39-46
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• 2016

According to general architecture of flight simulator made up of several independent rendering display systems, display synchronization problem between them naturally happens. In addition, since the flight simulator is usually implemented in the same networks where network delay is not big concern, it is necessary to consider different factors of existing synchronization technique. Among them, in this paper, we propose a new display synchronization scheme for flight simulator where each system has different rendering capacity. In the proposed scheme, each system is synchronized by considering maximum and minimum frames per second (FPS) while considering level of detail and latency. Also, experimental results are given to demonstrate the suitability of the proposed scheme for display synchronization scheme.

• 제어로봇시스템학회논문지
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• 제18권5호
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• pp.433-438
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• 2012

In this paper, a operation network system equipped with onboard wireless communication systems and ground-based mission control systems is proposed for swarm flight of small UAVs. This operating system can be divided into two networks, UAV communication network and ground control system. The UAV communication network is intend to exchange the informations of navigation, mission and flight status with minimum time delay. The ground control system consisted of mission control systems and UDP network. Proposed operation network system can make a swarm flight of various UAVs, execute complex missions decentralizing mission to several UAVs and cooperte several missions. Finally, PILS environments are developed based on the total operating system.

• International Journal of Aeronautical and Space Sciences
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• 제17권1호
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• pp.120-131
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• 2016

The full results of troubleshooting process related to the flight control system of a tilt-rotor type UAV in the flight tests are described. Flight tests were conducted in helicopter, conversion, and airplane modes. The vehicle was flown using automatic functions, which include speed-hold, altitude-hold, heading-hold, guidance modes, as well as automatic take-off and landing. Many unexpected problems occurred during the envelope expansion tests which were mostly under those automatic functions. The anomalies in helicopter mode include vortex ring state (VRS), long delay in the automatic take-off, and the initial overshoot in the automatic landing. In contrast, the anomalies in conversion mode are untrimmed AOS oscillation and the calibration errors of the air data sensors. The problems of low damping in rotor speed and roll rate responses are found in airplane mode. Once all of the known problems had been solved, the vehicle in airplane mode gradually reached the maximum design speed of 440km/h at the operation altitude of 3km. This paper also presents a comprehensive detailing of the control systems of the tilt-rotor unmanned air vehicle (UAV).

• 한국항공운항학회지
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• 제18권1호
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• pp.19-26
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• 2010

To expand the application area of global navigation satellite systems, precision landing is one of the most critical area to be solved. For the development and validation of the precision landing system, many aspects need to be analyzed including the system architecture, signal characteristics, atmospheric delay, communication delay, accuracy, integrity, and availability. Among them, the signal characteristics analysis requires the processing of measurements collected by real-flight experiments. This paper presents the processing results of the real measurements collected by a flight and landing experiment. To process and analyze the data, double differencing position-domain hatch filter is utilized. Accuracy of the proposed filter is evaluated utilizing reference trajectory generated by commercial software. Finally, by comparing with conventional range domain characteristics of position domain filter is analyzed.

• Journal of Positioning, Navigation, and Timing
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• 제2권1호
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• pp.49-57
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• 2013

When pseudolite navigation system is applied to wide area, the tropospheric delay is the main error factor. In this study, we experimentally compared and analyzed the performance of the conventional pseudolite tropospheric delay models. The integration method using radiosonde meteorological data was suggested to derive the reference value for the comparison and analysis. Flight tests were carried out to analyze the performance of the tropospheric delay models according to the elevation angle and distance conditions between the user receiver and the pseudolite. As the results of this study, we provided the basis for the choice of tropospheric delay model appropriate to the relative location characteristics of the pseudolite and the user.

• 한국항공운항학회:학술대회논문집
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• 한국항공운항학회 2007년 춘계학술대회 논문집
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• pp.11-12
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• 2007