• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.4
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• pp.77-84
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• 2015

Recently, as the needs for eco-friendly aero propulsion system increase gradually, many study works have been conducted to develop the hybrid propulsion system for High Altitude Long Endurance(HALE) UAV. In this study, we analyzed both suitable energy distribution and management methodology among the total energy collected from solar cell and the total required energy of aerial vehicle and required energy of the regenerative fuel cell(RFC) for driving in the night time and optimized the energy balance mechanism based on the ascribed mission profile.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2006.05a
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• pp.152-157
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• 2006

Satellite imagery is generally used for investigating the damage from natural disaster for wide area and remotely piloted vehicle or aerial photos are used for the local damage. But for more detailed information such as damages of public facilities, these methods are inadequate and so in this case field surveying has been carried out. We tried to estimate the damage of public facilities faster and more accurately using photogrammetric method. We developed a digital stereo camera system by fixing two digital cameras on a frame, and with this system the photos of actually damaged areas were collected. The damages were estimated from these stereo photos. Then the estimated data was compared with field surveying data in order to verify our system.

• Korean Journal of Remote Sensing
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• v.32 no.3
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• pp.275-285
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• 2016

This study analyzes the accuracy of ortho imagery based on whether camera calibration performed or not, using an unmanned aerial vehicle which equipped smart camera. Photgrammetric UAV system application was developed and smart camera performed image triangulation, and then created image as ortho imagery. Image triangulation was performed depending on whether interior orientation (IO) parameters were considered or not, which determined at the camera calibration phase. As a result of the camera calibration, RMS error appeared 0.57 pixel, which is more accurate compared to the result of the previous study using non-metric camera. When IO parameters were considered in static experiment, the triangulation resulted in 2 pixel or less (RMSE), which is at least 200 % higher than when IO parameters were not considered. After generate ortho imagery, the accuracy is 89% higher when camera calibration are considered than when they are not considered. Therefore, smart camera has high potential to use as a payload for UAV system and is expected to be equipped on the current UAV system to function directly or indirectly.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.5
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• pp.117-127
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• 2018

The author tried to propose the orthographic and DTM (digital terrain model) creation and evaluate the accuracy for an university campus using UAV (unmanned aerial vehicle) system. Most previous studies used GPS-based data, but in this paper, the observations of triangulation level measurements was used for comparison of accuracy. Accuracy analysis results showed that the operational requirements for aerial photographic standards are satisfied in all scenaries. The author confirmed availability in aviation photo measurements and applications using UAV (Drone). In order to create a sophisticated DTM and contour, we need to eliminate interference from building, trees, and artificial objects. The results of this study are expected to be used as the basis for future studies in the creation of DTM and the accuracy assessments using Drone.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.9
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• pp.724-733
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• 2017

Accidents caused by upset condition leads to fatal damage to both manned and unmanned aircraft. This paper deals with real-time detection of these aircraft upset situations to prevent further severe situations. Firstly, the difference between sensor measurement and predicted measurement from Extended Kalman filter is monitored to determine whether a target aircraft goes into an upset condition or not. In addition, repeating the time update stage of the Extended Kalman filter for a specific length of time can enable future upset situation prediction. The results of aforementioned both the approaches will build a bridge to upset prevention for future generation of manned/unmanned aircraft.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.3
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• pp.251-262
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• 2021

The airworthiness certification of lightning indirect effects becomes an important issue in personal air vehicles (PAVs), which are being actively developed around the world. PAVs are very vulnerable to lightning strikes, because of miniaturization, use of the electric engines, composite materials, and application of unmanned navigation systems. In this study, we first examined various steps of certifications for lightning indirect effects shown in AC 20 136B issued by the Federal Aviation Administration (FAA). We then applied certification guidelines for equipment transient design level listed in RTCA DO 160G Section 22 to PAVs and investigated lightning transient environments inside the PAVs. We also analyzed the aircraft level tests specified in SAE ARP 5416A by using electromagnetic computational analysis software EMA3D. Finally, we analyzed the actual transient level for PAVs and derived the data necessary for conformity certification.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.1
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• pp.61-69
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• 2013

In an evaluation process of aircraft flying qualities, a clear and concise application interface is important since an evaluation process requires numerous repeated evaluation. This flight evaluation program have implemented efficient flight evaluation user interface along with changed trim condition interface and composed of comprehensive evaluation interface have mounted all automated FQ evaluation modules that was selected to be compose of 14 items in respect of an unmanned fixed-wing aircraft. Accordingly when it is necessary to design the flight control system as well as to develop a FQ considered aircraft, this S/W can be utilized as a tool that is a useful test evaluation S/W with scalability and enable to reduce the time and the cost of verification and evaluation process.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.6
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• pp.488-494
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• 2013

The control law design and analysis environment of the FBW helicopter system have been developed using model base design method. The model based design is generally used in a aircraft, unmanned aerial system and automobile as well as rotorcraft development. The model based design provides many advantages such as development risk and schedule reduction using simulation and autocode generation. This paper describes a development of process for verification and validation of auto generated code for FBW helicopter flight control law. And this process is applied for Fly-By-Wire Helicopter Development Project. The results of functional test for auto generated code meet several specific requirements.

• Journal of Biosystems Engineering
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• v.35 no.4
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• pp.215-223
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• 2010

In order to develop an precision aerial pesticide application system to be attached to an unmanned helicopter which can be applied to small lots of land, this study analyzed the flowing and spraying characteristics of the spray droplets by the main rotor downwash by setting the application conditions at the flight altitude of 3 m, the diameter of main rotor of 3.1 m, the boom length of around 2.8 m, and the spraying rate of 8 L/ha. The results of this study are summarized below. Through analysis of the covering area ratio of the spray droplets by main rotor downwash by nozzle type, boom with tilt angle and height, it was found that the covering area ratio of the twin flat-fan nozzle of around 25% was more uniform than other types of nozzle, also boom with $10^{\circ}$ tilt angle and spraying height of 3 m was shown to be the appropriate conditions for aerial application of pesticides. It was found that the nozzle position to minimize the scattering loss of spray droplets due to vortex phenomenon at both ends of the main rotor was around 10 cm from the end of the main rotor. An application test for the aerial pesticide application system attached to the HUA-ACEI unmanned helicopter developed by the Rural Development Administration showed that the range of covering area ratio of the spray droplets was 10-25%, and the spraying width was approximately 7 m when over 10% of covering area ratio was considered for valid spraying.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.9
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• pp.88-93
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• 2003

This Paper described the simulation program development for helicopter. In the design of flight control system to accomplish some special missions like UAV, it is important to minimize the execution time obtaining a linear model from nonlinear model that is used for design of controller. The first step for this kind of purpose is to complete a nonlinear model that contains full dynamic characteristics. The second step is to get the trim values that are obtained from the nonlinear model by solving an algebraic equation. And then stability and control derivatives are derived through hovering to forward flight by numerical perturbation that will be used for linear model for a specified flight condition. The software program(HeliSim) is developed by using MATLAB GUI and will provide easy modeling procedure. The suggested method in this paper is much more simpler than any other method like a fully scale helicopter model. The advantage of our suggested method will reduce the computational time due to simple formula to extract a linear model from nonlinear model that will be beneficially used for flight control system of unmanned helicopter by some reduction of computational load.