• Title/Summary/Keyword: Small UAVs

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Target Level of Safety Analysis in Airworthiness Certification for Military UAV (군용무인기의 감항인증 목표안전수준 분석)

  • Lee, Narae;Jeon, Byung-Il;Chang, Young-Keun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.10
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    • pp.840-848
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    • 2013
  • Airworthiness certification of military aircraft is a government's certification that it must have airworthiness and ability to demonstrate its requested function and performance. NATO released STANAG-4671 to establish the minimum airworthiness requirements for UAVs between 150kg and 20,000kg MTOW in 2009. Up to now, there are no clear airworthiness certification criteria and guideline for small UAV which is less than 150kg. STANAG-4671 is used for military UAV airworthiness certification in Korea as Other Airworthiness Certification Criteria. However, since STANAG-4671 requires the same Target Level of Safety without regard to MTOW, excessive Target Level of Safety or design requirements could be applied to relatively small-medium UAV. In this paper, classification and criteria of airworthiness certification for military UAV were investigated and a Target Level of Safety was analyzed based on MTOW using ground victim criteria.

FPGA based HW/SW co-design for vision based real-time position measurement of an UAV

  • Kim, Young Sik;Kim, Jeong Ho;Han, Dong In;Lee, Mi Hyun;Park, Ji Hoon;Lee, Dae Woo
    • International Journal of Aeronautical and Space Sciences
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    • v.17 no.2
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    • pp.232-239
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    • 2016
  • Recently, in order to increase the efficiency and mission success rate of UAVs (Unmanned Aerial Vehicles), the necessity for formation flights is increased. In general, GPS (Global Positioning System) is used to obtain the relative position of leader with respect to follower in formation flight. However, it can't be utilized in environment where GPS jamming may occur or communication is impossible. Therefore, in this study, monocular vision is used for measuring relative position. General PC-based vision processing systems has larger size than embedded systems and is hard to install on small vehicles. Thus FPGA-based processing board is used to make our system small and compact. The processing system is divided into two blocks, PL(Programmable Logic) and PS(Processing system). PL is consisted of many parallel logic arrays and it can handle large amount of data fast, and it is designed in hardware-wise. PS is consisted of conventional processing unit like ARM processor in hardware-wise and sequential processing algorithm is installed on it. Consequentially HW/SW co-designed FPGA system is used for processing input images and measuring a relative 3D position of the leader, and this system showed RMSE accuracy of 0.42 cm ~ 0.51 cm.

A Study on the Changes in the Physical Environment of Resources in Rural Areas Using UAV -Focusing on Resources in Galsan-Myeon, Hongseong-gun- (무인항공기를 활용한 농촌 지역자원의 물리적 환경변화 분석연구 - 홍성군 갈산면 지역자원을 중심으로 -)

  • An, Phil-Gyun;Kim, Sang-Bum;Cho, Suk-Yeong;Eom, Seong-Jun;Kim, Young-Gyun;Cho, Han-Sol
    • Journal of the Korean Institute of Rural Architecture
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    • v.23 no.4
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    • pp.1-12
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    • 2021
  • Recently, the use of unmanned aerial vehicles (UAVs) is increasing in the field of land information acquisition and terrain exploration through high-altitude aerial photography. High-altitude aerial photography is suitable for large-scale geographic information collection, but has the disadvantage that it is difficult to accurately collect small-scale geographic information. Therefore, this study used low-altitude UAV to monitor changes in small rural spaces around rural resources, and the results are as follows. First, the low-altitude aerial imagery had a very high spatial resolution, so it was effective in reading and analyzing topographic features. Second, an area with a large number of aerial images and a complex topography had a large amount of point clouds to be extracted, and the number of point clouds affects the three-dimensional quality of rural space. Third, 3D mapping technology using point cloud is effective for monitoring rural space and rural resources because it enables observation and comparison of parts that cannot be read from general aerial images. In this study, the possibility of rural space analysis of low-altitude UAV was verified through aerial photography and analysis, and the effect of 3D mapping on rural space monitoring was visually analyzed. If data acquired by low-altitude UAV are used in various forms such as GIS analysis and topographic map production it is expected to be used as basic data for rural planning to maintain and preserve the rural environment.

A Comparison of Control Methods for Small UAV Considering Ice Accumulation and Uncertainty (결빙 현상과 불확실성을 고려한 소형 무인항공기 제어기법 비교 연구)

  • Hyodeuk An;Jungho Moon
    • Journal of Aerospace System Engineering
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    • v.17 no.5
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    • pp.34-41
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    • 2023
  • This paper applies the icing effect and wing rock uncertainty to small unmanned aerial vehicles (UAVs), which have recently attracted attention. Attitude control simulations were performed using various control methods. First, the selected platform, the Skywalker X8 UAV with blended wing-body (BWB) configuration, was linearized for both its baseline form, and a form with applied icing effects. Subsequently, using MATLAB SimulinkⓇ, simulations were conducted for roll and pitch attitude control of the baseline configuration and the configuration with icing effects, employing disturbance observer-based PID control, model reference adaptive control, and model predictive control. Furthermore, the study introduced wing rock uncertainty simultaneously with icing effects on the configured model-a combination not previously explored in existing research-and conducted simulations. The performance of each control Method was compared and analyzed.

Methodology of Test for sUAV Navigation System Error (소형무인항공기 항법시스템오차 시험평가 방법)

  • SungKwan Ku;HyoJung Ahn;Yo-han Ju;Seokmin Hong
    • Journal of Advanced Navigation Technology
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    • v.25 no.6
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    • pp.510-516
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    • 2021
  • Recently, the range of utilization and demand for unmanned aerial vehicle (UAV) has been continuously increasing, and research on the construction of a separate operating system for low-altitude UAV is underway through the development of a management system separate from manned aircraft. Since low-altitude UAVs also fly in the airspace, it is essential to establish technical standards and certification systems necessary for the operation of the aircraft, and research on this is also in progress. If the operating standards and certification requirements of the aircraft are presented, a test method to confirm this should also be presented. In particular, the accuracy of small UAV's navigation required during flight is required to be more precise than that of a manned aircraft or a large UAV. It was necessary to calculate a separate navigation error. In this study, we presented a test method for deriving navigation errors that can be applied to UAVs that have difficulty in acquiring long-term operational data, which is different from existing manned aircraft, and conducted verification tests.

Orthophoto and DEM Generation in Small Slope Areas Using Low Specification UAV (저사양 무인항공기를 이용한 소규모 경사지역의 정사영상 및 수치표고모델 제작)

  • Park, Jin Hwan;Lee, Won Hee
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.34 no.3
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    • pp.283-290
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    • 2016
  • Even though existing methods for orthophoto production in traditional photogrammetry are effective in large areas, they are inefficient when dealing with change detection of geometric features and image production for short time periods in small areas. In recent years, the UAV (Unmanned Aerial Vehicle), equipped with various sensors, is rapidly developing and has been implemented in various ways throughout the geospatial information field. The data and imagery of specific areas can be quickly acquired by UAVs at low costs and with frequent updates. Furthermore, the redundancy of geospatial information data can be minimized in the UAV-based orthophoto generation. In this paper, the orthophoto and DEM (Digital Elevation Model) are generated using a standard low-end UAV in small sloped areas which have a rather low accuracy compared to flat areas. The RMSE of the check points is σH = ±0.12 m on a horizontal plane and σV = ±0.09 m on a vertical plane. As a result, the maximum and mean RMSE are in accordance with the working rule agreement for the airborne laser scanning surveying of the NGII (National Geographic Information Institute) on a 1/500 scale digital map. Through this study, we verify the possibilities of the orthophoto generation in small slope areas using general-purpose low specification UAV rather than a high cost surveying UAV.

Compensation of Magnetometer in the Navigation System for Unmanned Helicopter using an Electric Motor (전기모터를 사용한 소형 무인헬리콥터에 활용될 항법장치용 자장계의 보상)

  • Lee, Gilho;Jo, Sungbeom;Kim, Jungsung;Choi, Keeyoung;Kee, Changdon;Song, Yongkyu;Koo, Wheonjoon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.11
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    • pp.997-1003
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    • 2012
  • GNSS and ARS are the most common sensors in low-end UAVs. However, these sensors are vulnerable to built-in errors and cannot measure the body heading independently. The GNSS/INS cannot fully compensate the IMU errors in initial alignment process and rectilinear flights. For an unmanned helicopter, a magnetometer can be more useful than any other sensors to obtain heading information. However, the electric motor which drives small helicopter UAV keeps the magnetometer from reading the pure magnetotelluric vector. This paper shows the effects of electric motor on the magnetometer readings, and presents a method to compensate the effects. The results are verified with flight test data. The simulation and experimental results in this paper proves that aiding GNSS/INS with magnetometer increases observability and improves accuracy.

Configuration and Performance Analyses for Conceptual Design of Small and Mid-Unmanned Aerial Vehicles (중소형 무인항공기 개념설계를 위한 형상 및 성능 분석)

  • Jeon, Byung-Il;Lee, Narae;Chang, Young-Keun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.6
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    • pp.478-487
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    • 2014
  • The simplified performance analysis and initial configuration design are required for the successful development of UAV during the conceptual design, in which empirical formulas and trend equations are utilized for the UAV performance analysis. In the conceptual design phase various UAV configurations may be considered, however, it is very inefficient and unnecessary to consider all configurations for the conceptual design. In this study, the database for the fixed wing UAVs whose MTOW is between 50kg and 1,500kg was also constructed for the selection of configuration frequently used. The parametric analyses were performed for major performance parameters, and trend equations were developed through regression analyses for these individual performance parameters.

Accuracy of Drone Based Stereophotogrammetry in Underground Environments (지하 환경에서의 드론 기반 입체사진측량기법의 정확도 분석)

  • Kim, Jineon;Kang, Il-Seok;Lee, Yong-Ki;Choi, Ji-won;Song, Jae-Joon
    • Explosives and Blasting
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    • v.38 no.3
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    • pp.1-14
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    • 2020
  • Stereophotogrammetry can be used for accurate and fast investigation of over-break or under-break which may form during the blasting of underground space. When integrated with small unmanned aerial vehicles(UAVs) or drones, stereophotogrammetry can be performed much more efficiently. However, since previous research are mostly focused on surface environments, underground applications of drone-based stereophotogrammetry are limited and rare. In order to expand the use of drone-based stereophotogrammetry in underground environments, this study investigated a rock surface of a underground mine through drone-based stereophotogrammetry. The accuracy of the investigation was evaluated and analyzed, which proved the method to be accurate in underground environments. Also, recommendations were proposed for the image acquisition and matching conditions for accurate and efficient application of drone-based stereophotogrammetry in underground environments.

Aerodynamic Characteristics of the Blended-Wing-Body for the Position and Aspect Ratio of the Inlet and Outlet of an Embedded Distributed Propulsion System (Embedded Type 분산 추진 장치의 입·출구 형상 및 위치 변화에 따른 융합익기의 공력해석)

  • Kim, Hyo-Seop;Choi, Hyun-Min;Cho, Jin-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.6
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    • pp.467-474
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    • 2012
  • UAVs for reconnaissance and intelligence operations require long endurance capability, which demands high efficiency of the propulsion system. The distributed propulsion system(DPS) generates the thrust by replacing a large propulsion system with a number of small propulsion systems. A DPS distributed along the wing span can produce gains in propulsion efficiency by reducing ejection velocity. Also, the ingestion of boundary layers through the distributed DPS inlet and ejecting flow from the outlet can improve the lift to drag ratio of the vehicle. This study investigates the effects of locations and size of the inlet and outlet of the DPS on the blended-wing-body design based on Eppler 337 airfoil, with a CFD tool. The fans in the DPS are modeled as actuator disks for computational efficiency. The best location and aspect ratio of the inlet and outlet are found from lift-to-drag ratio and pitching moment considerations.