• Korean Journal of Remote Sensing
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• v.20 no.4
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• pp.227-234
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• 2004

The synchronization of Time Delay and Integration (TDI) against the temporal variation of osculating altitude in the operation of high resolution satellite imager was studied. The characteristics of osculating altitude variation was analyzed and its impact on the performance of TDI imger was also investigated. A practical ]me rate control method was proposed to compensate instantaneous TDI mismatch due to the osculating altitude variation, so that geometrical performance enhancement was achieved by the proposed method. This study is applicable to real satellite operation and can be useful for satellite image quality enhancement.

• Journal of the military operations research society of Korea
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• v.34 no.1
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• pp.31-45
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• 2008

This paper describes a development of the operational architecture of a low altitude air defense automation system using a systems engineering approach. The future battlefield is changing to new system of systems that command and control by the network based BM/C4I. Also, it is composed of various sensors and shooters in an single theater. Future threats may be characterized as unmanned mewing bodies that the strategic effect is great such as UAVs, cruise missiles or tactical ballistic missiles. New threats such as low altitude stealth cruise missiles may also appear. The implementation of a low altitude air defense against these future threats is required to complex and integrated approach based on systems engineering. In this view, this work established an operational scenario and derived operational requirements by identifying mission and future operational environments. It is presented the operational architecture of the low altitude air defense automation system by using the CORE 5.0.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.749-756
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• 2013

This paper presents an algorithm concerning the ground altitude measurement using a laser altimeter and an ultrasonic rangefinder for UAV(Unmanned Aerial Vehicle). A simple ground test conducted using the laser altimeter and ultrasonic rangefinder that are used for conducting the low altitude measurement of UAV and identify the characteristics of each sensor. Especially, the disadvantages of the laser altimeter were checked through the ground test. After that who those are participated in this paper planned the algorithm which is complemented by the ultrasonic rangefinder and the experiment was conducted. The laser altimeter and the ultrasonic rangefinder were fused by a loosely coupled method by Kalman filter. The paper shows that stable value of altitude complemented by the ultrasonic rangefinder that covers the laser altimeter's drawbacks can be measured through the ground test.

• The Journal of Korean Institute of Information Technology
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• v.16 no.12
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• pp.49-56
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• 2018

As the era of the 4th industrial revolution comes, there is a growing interest in the use of UAVs. While various technologies are being developed using drones, controlling flight of drones is the most basic. Hovering control is essential in order to enable autonomous flight, especially during flight control of drones. In this paper, we design drones based on ATmega2560, Sonar, Optical Flow, and acceleration / gyro 6 axis sensor for drones hovering control, and developed horizontal control, altitude control, position tracking and fixed algorithm based on PID control. In this research, in order to measure the objective result of the drone, keeping the altitude immediately after the drone takes off according to the time, measure the movement value until the position is fixed and stable hovering is maintained and compared analyzed. Experimental results show that the drones can stably hover within 4cm horizontal and 2cm vertical from 50cm above the reference coordinates.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.3
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• pp.18-27
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• 2015

Many studies have shown that having perception of spatial information is important for air traffic control officer (ATCO) since it helps them understand the current situation and predict the situation it leads to. However, little or no research has been done to investigate if there is any difference at the levels of expertise in perceiving spatial information and predicting a prospective situation. This study investigates the difference between expert and novice ATCO groups in how accurately each group of ATCO perceive spatial information such as position, altitude, speed, and flying direction, and predicting such information they will encounter shortly. In completing a task to watch the movement of airplanes displayed on the computer monitor as a blip, the participants were asked to predict the position, speed, and the altitude of the aircraft in a minute by marking on the sector map. The results show that the expert group performed better in accuracy and had tendency to overestimate on position and altitude; however, no significant difference was found between the two groups in terms of reading a flying direction. Therefore reading a flying direction may not be a reliable indicator to judge expertise of ATCO. But the expert group shows better predicting performance by perceiving spatial information such as airplane's position and altitude with feeling on time. The study suggests that it is important to enhance perceptive skills in ATCO training in improving their expertise in predicting accuracy traffic situation, preventing from air collision, and improving productivity for more efficient air traffic flow. A further study on the relationship between the perception of spatial information and the sense of time in predicting future information and effectiveness as an independent factor would contribute to providing more insights into expertise of ATCOs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3161-3167
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• 2010

Hall sensors of BLDC(brushless DC) motor are used to detect a position information for a control mechanism, which implements an algorithm for velocity and position control. Actual azimuth and altitude were measured to evaluate a control precision. The measurement revealed comparatively good accuracy that the measured values were $2.02^{\circ}$ and $1.01^{\circ}$ respectively, and the maximum error falls within $1.86^{\circ}$. The developed monitoring system of photovoltaic generation plants is a LCU(Local Control Unit) based on an integrated monitoring system which supports 1:N method for multiple simultaneous connections, remote control and real-time system state monitoring.

• Journal of Advanced Navigation Technology
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• v.21 no.5
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• pp.450-458
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• 2017

This paper presents dynamic modelling and simulation study on attitude/altitude control of an insect-mimicking flapping micro aerial vehicle during hovering. Mathematical modelling consists of three parts: simplified flapping kinematics, flapping-wing aerodynamics, and six degree of freedom dynamics. Attitude stabilization is accomplished through linear quadratic regulator based on the linearized model of the time-varying nonlinear system, and altitude control is designed in the outer loop using PID control. The performance of the proposed controller is verified through numerical simulation where attitude stabilization and altitude control is done for hovering. In addition, it is confirmed that the attitude channel by periodic control is marginally stable against periodic pitching moment caused by flapping.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.105-110
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• 2008

Unmanned helicopter has several abilities such as vertical take off, hovering, low speed flight at a specific altitude. Such vehicles are becoming popular in actual applications such as search and rescue, aerial reconnaissance and surveillance in the case of a large size disaster and forest fire. In this paper, a flight control system was designed for an unmanned helicopter. This paper was concentrated on describing the systematic design, electronic equipments and their interconnections for realizing the autonomous flight and aerial monitoring. A study on the autonomous waypoint navigation and altitude control performance were performed and tested on a test unmanned helicopter and the performance and the feasibility were represented.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1863-1866
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• 2005

In this paper we propose a platform that is applicable to low altitude remote sensing. Basic idea of the platform is based on the model helicopter. On big difference from the conventional model helicopter is that our platform has four main rotors. Furthermore, vision control strategy is introduced so that operator can use the platform without any specialized intensive knowledge

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.137-143
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• 2013

In recent years, the interest in a various energy sources is increasing. Among these energies, there are many kinds of researches for the kite which can generate the energy from high-altitude wind power. There are many attempts to apply the kite to the wind power generation and ship salvage, and it must require the flight control of the kite for this applications. In this paper, we suggest this flight controller based on the flight technique of sport kite. For this controller based on the human controller, we design the simple fuzzy controller with simple fuzzy rules.