• 항공우주시스템공학회지
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• 제6권1호
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• pp.19-25
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• 2012

Nowadays, the demand of civil application of an UAV has been being increased all over the world. And many projects are going on to develop a new regulatory system for an UAV to access a national airspace. Especially, to fly UAV over the non-restricted airspace as a standard airworthiness standard, many authority funded research institutes and associations are studying regulatory environment. For the UAV to access civil airspace, the certification system of the aviation regulation have to allow this. FAA of US, CASA of Australia and European authorities are now issuing an experimental airworthiness certificate to a civil UAV. This is the first step of issuing a standard airworthiness certificate. And many people believe that civil UAV can fly over a NAS if some technical issues are resolved. In this study, I would like to present an international trends of a civil UAV regulation system, reliability trend of unmanned aerial system and would like to bring up a our regulatory environment and suggest an UAV regulatory policy.

• 항공우주시스템공학회지
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• 제2권4호
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• pp.31-37
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• 2008

To operate UAV in the civil airspace, the airworthiness of UAV system have to be proven by the civil certification system. However, it is difficult for UAV to be certified by the existing certification system because the existing certification system has been developed for the manned aircraft. So, many civil aviation authorities and research institutes are studying developing airworthiness standards for UAV certification. To develop an airworthiness standards for UAV, the airworthiness level of safety have to be established based on UAV categorization. I would like to introduce an quantitative methods for establishing airworthiness level of safety of UAV based on UAV categorization and example of Smart UAV.

• Journal of Positioning, Navigation, and Timing
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• 제4권2호
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• pp.57-65
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• 2015

Global Navigation Satellite System (GNSS) including Global Positioning System (GPS) is an important element for navigation of both the military and civil Unmanned Aerial Vehicle (UAV). Contrary to the military UAVs, the civil UAVs use the civil signals which are unencrypted, unauthenticated and predictable. Therefore if the civil signals are counterfeited, the civil UAV’s position can be manipulated and the appropriate movement of the civil UAV to the target point is not achieved. In this paper, spoofing on the autonomous navigation UAV is implemented through field experiments. Although the demanded conditions for appropriate spoofing attack exists, satisfying the conditions is restricted in real environments. So, the Way-point of the UAV is assumed to be known for experiments and assessments. Under the circumstances, GPS spoofing signal is generated based on the Software-based GNSS signal generator. The signal is emitted to the target UAV using the antenna of the spoofer and the effect of the signal is analyzed and evaluated. In conclusion, taking the UAV to the target point is hardly feasible. To implement the spoofing as expectation, the position and guidance system of the UAV has to be known. Additionally, the GPS receiver on the UAV could be checked whether it appropriately tracks the spoofing signal or not. However, the effect of the spoofing signal on the autonomous UAV has been verified and assessed through the experimental results. Spoofing signal affects the navigation system of the UAV so that the UAV goes off course or shows an abnormal operation.

• Smart Structures and Systems
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• 제13권6호
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• pp.1065-1094
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• 2014

Civil engineers always face the challenge of uncertainty in planning, building, and maintaining infrastructure. These works rely heavily on a variety of surveying and monitoring techniques. Unmanned aerial vehicles (UAVs) are an effective approach to obtain information from an additional view, and potentially bring significant benefits to civil engineering. This paper gives an overview of the state of UAV developments and their possible applications in civil engineering. The paper begins with an introduction to UAV hardware, software, and control methodologies. It also reviews the latest developments in technologies related to UAVs, such as control theories, navigation methods, and image processing. Finally, the paper concludes with a summary of the potential applications of UAV to seismic risk assessment, transportation, disaster response, construction management, surveying and mapping, and flood monitoring and assessment.

• 상하수도학회지
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• 제32권6호
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• pp.573-581
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• 2018

The purpose of this study is to evaluate the fixed wing type domestic UAV for monitoring of algae bloom in aquatic environment. The UAV used in this study is operated automatically in-flight using an automatic navigation device, and flies along a path targeting preconfigured GPS coordinates of desired measurement sites input by a flight path controller. The sensors used in this study were Sequoia multi-spectral cameras. The photographed images were processed using orthomosaics, georeferenced digital surface models, and 3D mapping software such as Pix4D. In this study, NDVI(Normalized distribution vegetation index) was used for estimating the concentration of chlorophyll-a in river. Based on the NDVI analysis, the distribution areas of chlorophyll-a could be analyzed. The UAV image was compared with a airborne image at a similar time and place. UAV images were found to be effective for monitoring of chlorophyll-a in river.

• 한국건설관리학회논문집
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• 제18권5호
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• pp.41-49
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• 2017

토목공사 발주기관은 공사현장이 대부분 원거리에 위치하고 담당공무원도 다수의 현장을 관리하게 되므로 간접적 방식으로 현장을 관리하고 있다. 토목공사 현장은 광범위한 작업구역을 가지므로 현장 실무자의 보고에 의한 간접적 관리방식으로는 사업전체의 현황을 신속하게 파악하기가 쉽지 않다. 이러한 문제점을 해소하기 위해 발주기관과 현장간의 현장관리시스템은 오프라인에서 온라인방식으로 변화되고 있다. 본 연구에서는 UAV에서 취득한 현장의 3차원정보를 활용하여 원거리에 위치한 현장과 감독기관간에 관련 정보를 온라인으로 공유할 수 있는 개선된 현장관리시스템을 제시한다. 이를 위하여 연구에서는 다수의 실제 현장의 현장관리 운영체계의 문제점을 분석하여 UAV활용 현장관리시스템에 필요로 하는 공사현황보고 및 온라인 정보관리 등의 주요기능을 도출하였다. 연구에서 개발된 시스템은 실제 공사 중인 현장에 적용하여 활용성을 검증하였으며, 다수의 현장 조사를 통하여 기존의 간접적 현장관리 방식과의 효율성 개선사항을 분석하였다.

• 항공우주시스템공학회지
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• 제9권3호
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• pp.17-22
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• 2015

The UAV industry grows rapidly and the civil UAV market which preparing the commercial services is expected to accelerate the growth. The new opportunities from the technological progress and deregulation show two kinds of organizational structure in the UAV industry. The companies from the traditional aircraft industry and the other sectors like IT industry have different organizational structures of the value chains, supply chains and the regulatory policies which related with them. And from the isomorphism theory it is predicted that those structures will change and converge to certain similar homogeneous features as the UAV industry matures. The matured form will be resulted by the new regulatory policies about the airspace, certifications and the operation rules about the UAV and the future market size and growth speed are also affected by them.

• Computers and Concrete
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• 제31권5호
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• pp.457-468
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• 2023

Buildings, bridges, and dams are examples of civil infrastructure that play an important role in public life. These structures are prone to structural variations over time as a result of external forces that might disrupt the operation of the structures, cause structural integrity issues, and raise safety concerns for the occupants. Therefore, monitoring the state of a structure, also known as structural health monitoring (SHM), is essential. Owing to the emergence of the fourth industrial revolution, next-generation sensors, such as wireless sensors, UAVs, and video cameras, have recently been utilized to improve the quality and efficiency of building forensics. This study presents a method that uses a target-based system to estimate the dynamic displacement and its corresponding dynamic properties of structures using UAV-based video. A laboratory experiment was performed to verify the tracking technique using a shaking table to excite an SDOF specimen and comparing the results between a laser distance sensor, accelerometer, and fixed camera. Then a field test was conducted to validate the proposed framework. One target marker is placed on the specimen, and another marker is attached to the ground, which serves as a stationary reference to account for the undesired UAV movement. The results from the UAV and stationary camera displayed a root mean square (RMS) error of 2.02% for the displacement, and after post-processing the displacement data using an OMA method, the identified natural frequency and damping ratio showed significant accuracy and similarities. The findings illustrate the capabilities and reliabilities of the methodology using UAV to evaluate the dynamic properties of structures.

• 대한원격탐사학회지
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• 제36권5_3호
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• pp.1013-1025
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• 2020

UAV (Unmanned Aerial Vehicle) 플랫폼은 소규모 지역의 영상을 저비용으로 신속하게 취득이 가능하다는 장점이 있어 재난모니터링과 스마트시티 분야에 널리 활용되고 있다. UAV 기반 정사영상 및 DSM (Digital Surface Model) 제작 시 cm 급 정확도를 확보하기 위하여 UAV 영상의 위치보정을 위한 지상기준점(Ground Control Points, GCP)이 필수적이다. 하지만, 현장 GCP 취득을 위한 현장방문, 대공표지 설치에는 상당한 인력과 시간이 소요된다. 따라서 본 연구에서는 GCP 현장 취득을 대체하기 위한 방법으로 사전에 구축되어 활용가능한 세 가지 공간정보를 GCP로 이용하는 방법을 제시하였다. 연구에 사용한 세 가지 공간정보는 첫째, 25 cm 급 정사영상과 1:1000 수치지형도 기반 DEM (Digital Elevation Model), 둘째, 모바일매핑시스템(Mobile Mapping System, MMS)으로 취득한 점군 데이터, 셋째, MMS 데이터와 UAV 데이터를 융합하여 만든 하이브리드 점군 데이터이다. 세 가지 공간정보로부터 취득한 GCP를 이용하여 각각에 대하여 UAV 정사영상과 DSM (Digital Surface Model, DSM)을 생성하였다. 생성된 3가지 결과를 현장 RTK-GNSS 측량으로 취득한 검사점과 비교하여 3차원 위치 정확도평가를 진행하였다. 실험결과, 세 번째 경우인 MMS와 UAV를 융합한 하이브리드 점군 데이터를 GCP로 사용하였을 때, UAV 정사영상과 DSM의 최종 정확도가 수평방향의 RMSE는 8.9 cm, 수직방향의 RMSE는 24.5 cm로 가장 높게 나타났다. 또한, 현장 측량을 대체하기 위해 활용한 공간정보로부터 취득한 GCP의 분포는 수평 위치 정확도 보다 수직 위치 정확도에 더 많은 영향을 미치는 것으로 나타났다.

• 한국지리정보학회지
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• 제21권3호
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• pp.127-137
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• 2018

최근 들어 UAV(무인항공기) 및 드론을 이용하여 다양한 활용기술에 대한 연구들이 이루어지고 있다. 특히, 측량분야에서는 UAV에 탑재된 디지털 카메라나 다양한 센서들을 이용하여 취득된 고해상도의 영상자료를 바탕으로 해당 지형을 모니터링하거나, 고해상도의 정사영상 및 DSM, DEM을 생성하기 위한 기술에 관한 연구들이 수행되고 있다. 본 연구에서는 UAV와 VRS-GPS를 이용하여 GCP 정합수에 따른 정확도를 분석하여 보았다. 먼저 VRS-GPS를 이용해 지상기준점을 선점한 후 UAV를 이용하여 기본고도 150m로 촬영을 실시하였으며, 646장의 영상정보를 취득하여 DSM과 정사영상을 제작하기 위해 pix4d mapper버전을 사용하여 RMSE를 분석한 결과 GCP 정합수를 5장 이상만 하여도 국가 기본도(축척 : 1/5,000) 제작 작업규정의 오차범위를 준수하고 있어 수치지도 수정 갱신 업무까지도 충분이 활용이 가능한 것으로 판단되었다.