• Journal of Korean Society for Geospatial Information Science
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• v.23 no.2
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• pp.39-48
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• 2015

Lately, Unmanned Aerial Vehicles(UAV), Unmanned Aerial Systems(UAS) or also often known as drones, as a data acquisition platform and as a measurement instrument are becoming attractive for many photogrammetric surveying applications, especially generation of the high density point clouds(HDPC). This paper presents the performance evaluation of a low-cost rotary wing quadrocopter UAS for generation of the HDPC in a test bed environment. Its performance was assessed by comparing the coordinates of UAS based HDPC to the results of Network RTK GNSS surveying with 62 ground check points. The results indicate that the position RMSE of the check points are ${\sigma}_H={\pm}0.102m$ in Horizonatal plane, and ${\sigma}_V={\pm}0.209m$ in vertical, and the maxium deviation of Elevation was 0.570m within block area of ortho-photo mosaic. Therefore the required level of accuracy at NGII for production of ortho-images mosaic at a scale of 1:1000 was reached, UAS based imagery was found to make use of it to update scale 1:1000 map. And also, since this results are less than or equal to the required level in working rule agreement for airborne laser scanning surveying of NGII for Digital Elevation Model generation of grids $1m{\times}1m$ and 1:1000 scale, could be applied with production of topographic map and ortho-image mosaic at a scale of 1:1000~1:2500 over small-scale areas.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.249-249
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• 2016

무인항공기(UAV)는 군사적 목적으로 개발되었지만, 최근 다양한 분야에서 활용되고 있다. 수자원 관리를 위해서도 시대적 흐름에 따라 드론과 관련된 많은 연구가 진행되고 있다. 이수임 등(2015)은 UAV영상을 활용한 수변구조물의 DSM 생성 및 정확도 연구를 통해 지상 LIDAR와 같은 수준의 DSM 및 더욱 정확한 GCP 취득의 필요성을 제시했다. 이용창(2015)은 회전익 UAS 영상기반 고밀도 측점자료의 위치 정확도를 평가하였다. 이인수 등(2013)은 초경량 고정익무인항공기 사진측량기법의 정사영상 정확도 평가를 수행하였다. 또한 김민규 등(2010)은 풍수해 모니터링을 위한 UAV 적용성 분석을 실시하였고, 김홍래 등(2014)은 UAV를 활용한 감시정보정찰 임무분석 및 설계도구 개발을 위한 연구를 수행하였다. 상기와 같이 수자원 분야 활용을 위한 많은 연구가 보고 되고 있으나, 아직까지 드론 활용의 대부분은 항공영상 취득 및 분석기술 개발에 집중되어 있다. 본 연구에서는 무인항공기를 수재해 감시 및 관리 기술에 적용하기 위해 수행되었다. 수재해 감시 및 관리를 위한 방법으로 NIR(Near Infrared) 센서를 부착한 '재해관리용 드론'을 개발하고 현장실험을 수행하였다. 실험결과 NIR센서를 탑재한 드론은 수재해 관리에 매우 유용하게 활용될 수 있을 것으로 판단되었다.

• Journal of the Korean earth science society
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• v.24 no.3
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• pp.205-215
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• 2003

A precise and dense Bouguer anomaly is one of the most important data to improve the knowledge of our environment in the aspect of geophysics and physical geodesy. Besides the precise absolute gravity station net, we should consider two parts; one is to improve the precision in gravity measurement and correction of it, and the other is the density of measurement both in number and distribution. For the precise positioning, we have tested how we could use the GPS properly in gravity measurement, and deduced that the GPS measurement for 5 minutes would be effective when we used DGPS with two geodetic GPS receivers and the baseline was shorter than 40km. In this case we should use a precise geoid model such as PNU95. By applying this method, we are able to reduce the cost, time, and number of surveyors, furthermore we also get the benefit of improving in quality. Two kind of computer programs were developed to correct crossover errors and to calculate terrain effects more precisely. The repeated measurements on the same stations in gravity surveying are helpful not only to correct the drifts of spring but also to approach the results statistically by applying network adjustment. So we can find out the blunders of various causes easily and also able to estimate the quality of the measurements. The recent developments in computer technology, digital elevation data, and precise positioning also stimulate us to improve the Bouguer anomaly by more precise terrain correction. The gravity data of various sources, such as land gravity data (by Choi, NGI, etc.), marine gravity data (by NORI), Bouguer anomaly map of North Korea, Japanese gravity data, altimetry satellite data, and EGM96 geopotential model, were collected and processed to get a precise and dense Bouguer anomaly in and around the Korean Peninsula.