• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.429-429
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• 2004

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.11
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• pp.33-40
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• 2005

The reliability of flight control system(FCS) for Unmanned Air Vehicle(UAV) is underestimated because of the design restrictions such as small size, low cost and light weight. However because the failure of FCS may cause the loss of aircraft, the reliability of FCS must be analysed and validated whether it meet the reliability requirements in design phase.In this paper the failure rate of subsystems was divided with its function based on the design experience of FCS. The redundancy models which satisfy the system reliability requirements were suggested. These results may be utilized in the hardware design of FCS.

• Journal of Platform Technology
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• v.8 no.1
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• pp.3-9
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• 2020

In Korea, 63% of the nation's land is made up of forests, and the average temperature of the earth has been increasing. Forest service has been operating a proactive control system for preventing the spread of forest pests such as Pine wilt disease. but there were some hurdles in timely control due to weather, topography and manpower management difficulties. In this paper, we propose a model for building fast, accurate and efficient control system by categorizing the damage and dead wood automatically based on the images acquired using small unmanned aerial vehicles based on information and communication technology. In particular, the proposed model establishes an effective response system for government affairs through cooperation in the private sector. It can also create new jobs in the unmanned aerial vehicle business and service industries.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.3
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• pp.267-274
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• 2009

Recently, UAVs (Unmanned Aerial Vehicles) are expected much as the Unmanned Systems for various missions. These missions are often based on the Vision System. Especially, missions such as surveillance and pursuit have a process which is carried on through the transmitted vision data from the UAV. In case of small UAVs, monocular vision is often used to consider weights and expenses. Research of missions performance using the monocular vision is continued but, actually, ground and target model have difference in distance from the UAV. So, 3D distance measurement is still incorrect. In this study, Mean-Shift Algorithm, Optical Flow and Subspace Method are posed to estimate the relative depth. Mean-Shift Algorithm is used for target tracking and determining Region of Interest (ROI). Optical Flow includes image motion information using pixel intensity. After that, Subspace Method computes the translation and rotation of image and estimates the relative depth. Finally, we present the results of this study using images obtained from the UAV experiments.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.4 s.19
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• pp.20-25
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• 2004

The existing antenna that equipped with Micro Aerial Vehicle, microstrip antenna only can send and receive image signal because of limited bandwidth. But, proposed antenna that equipped with Micro Aerial Vehicle flight introduces tapered type patch antenna, also improves bandwidth then can transfer present location, altitude, movement speed. Furthermore, as a result of introduce stacked type, it transfers more quality of image signal, and represents most suitable performance in Korean peninsula that has many mountain peaks. In this paper, to transmit and receive the wideband signals with a antenna system, the wideband microstrip antenna is proposed and designed. This antenna operates at 2.4GHz. In this thesis, the resonance frequency of 2.4GHz and the reflective loss of the antenna of -22dB were calculated by measuring the fabricated Tapered Microstrip Patch Antenna which was designed with the resonance of 2.4GHz. The calculated gain and efficiency of antenna were 6.7dB and $60\%$ respectively. The characteristic of the bandwidth shows with $50\~60MHz$ which is $6.02\%$ at the basis of -l5dB reflective loss. The experimental results can be used in the characteristic of the resonators and this antenna produces a greatly enhanced bandwidth.

• Journal of Advanced Navigation Technology
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• v.16 no.4
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• pp.571-577
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• 2012

In this paper, we design a flight controller using a dynamic compensator for a small unmanned aerial vehicle. The proposed method ensures flight stability during altitude holding and waypoints passing by improving the transient response and steady state error. The control system consists of dual feedback loops with an inner loop and a outer loop. The inner loop has a PD controller to improves the transient response and the outer loop has a dynamic compensator to reduce overshoot in the transient response and improve the steady state error. The performance of the proposed method is evaluated by flight test on a small UAV.

• Journal of Advanced Navigation Technology
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• v.21 no.1
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• pp.145-152
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• 2017

As a popularization of small UAS to have improved flight performance and easiness of controlling, the UAS industry is increased and also small UAS is to be a new threat for airspace security of national strategic infrastructure. Rising the new threat makes the negative side effect of small UAS operation. This phenomena brought to new R&D needs "defense system" for small UAS/UAV - called Anti-Drone. The paper addressed case study of defects, accidents and threats by small UAS/UAV as world wide level, and research and development trend of UAS defense system as each technical category - CONOP (Concept of Operation), identification/recognition method and control/supremacy techniques. As a result, this suggests the direction what and where drone defense system should be applied first and required for Korean society in the view of society system (regime) and a point of view for minimizing side effect as UAS popularization.

• Journal of Advanced Navigation Technology
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• v.8 no.2
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• pp.105-111
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• 2004

This paper describes the design of navigation system for an unmanned target drone which is operated by Korean army as for anti-air gun shooting training. Current target drone is operated by pilot control of on-board servo motor via remote control system. Automatic flight control system for the target drone greatly reduces work load of ground pilot and can increase application area of the drone. Most UAVs being operated nowdays use high-priced sensors as AHRS and IMU to measure the attitude, but those are costly. This paper introduces the development of low-cost automatic flight control system with low-cost sensors. The integrated automatic flight control system has been developed by integrating combining power module, switching module, monitoring module and RC receiver as an one module. The performance of navigation for low cost unmanned aerial vehicle, unmanned target drone as our test bed in this paper is verified by both Hardware in the loop simulation(HILS) to test performance of GPS as GPS output frequency high and results of flight test.

• Journal of Aerospace System Engineering
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• v.11 no.4
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• pp.22-29
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• 2017

A study is performed for the effective detection method of a fault which is occurred during operation in a small turbojet engine with non-linear characteristics used by unmanned air vehicle. For this study the non-linear dynamic model of the engine is derived from transient thermodynamic cycle analysis. Also for inducing real operation conditions the controller is developed associated with unscented Kalman filter to estimate noises. Sequential probability ratio test is introduced as a real time method to detect a fault which is manipulated for simulation as a malfunction of rotational speed sensor contaminated by large amount of noise. The method applied to the fault detection during operation verifies its effectiveness and high feasibility by showing good and definite decision performances of the fault.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.5
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• pp.407-415
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• 2002

In this paper, mutual coupling effect between antennas mounted on UAV(Unmanned Air Vehicle), operating In different frequency bands, is calculated for supposing efficient arrangement. For the calculation, FDTD method is used, simulation parameters are confined to distance between antennas, height of antennas, types of ground, etc. The simulation data are compared with those of other numerical method to confirm accuracy of the results. It is appeared that the critical factor of mutual coupling is height of an antenna relative to that of the other antenna.