Accuracy assessment of real-time kinematics(RTK)measurements on unmanned aerial vehicles(UAV)for direct geo-referencing

作     者：Desta Ekaso Francesco Nex Norman Kerle Desta Ekaso;Francesco Nex;Norman Kerle

作者机构：Department of Earth Systems AnalysisITC-Faculty of Geo-Information Science and Earth Observation of the University of TwenteEnschedeThe NetherlandsDepartment of Earth Systems AnalysisITC-Faculty of Geo-Information Science and Earth Observation of the University of TwenteEnschedeThe NetherlandsDepartment of Earth Systems AnalysisITC-Faculty of Geo-Information Science and Earth Observation of the University of TwenteEnschedeThe Netherlands 

出 版 物：《Geo-Spatial Information Science》 (地球空间信息科学学报（英文）)

年 卷 期：2020年第23卷第2期

页      面：165-181页

核心收录：

学科分类：0303[法学-社会学] 0709[理学-地质学] 08[工学] 0708[理学-地球物理学] 0705[理学-地理学] 0816[工学-测绘科学与技术] 081602[工学-摄影测量与遥感] 0813[工学-建筑学] 0833[工学-城乡规划学] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：The authors would like to thank DRONExpert company for their contribution in developing the GNSS RTK/camera synchronization module. Special thanks are given to the UAV lab department of ITC for providing UAV and GPS equipment whenever it was required. 

主　　题：UAV GNSS RTK direct georeferencing aerial triangulation lever arm offset 

摘      要：Geospatial information acquired with Unmanned Aerial Vehicles(UAV)provides valuable decision-making support in many different domains,and technological advances coincide with a demand for ever more sophisticated data products.One consequence is a research and development focus on more accurately referenced images and derivatives,which has long been a weakness especially of low to medium cost UAV systems equipped with relatively inexpensive inertial measurement unit(IMU)and Global Navigation Satellite System(GNSS)receivers.This research evaluates the positional accuracy of the real-time kinematics(RTK)GNSS on the DJI Matrice 600 Pro,one of the first available and widely used UAVs with potentially surveying-grade performance.Although a very high positional accuracy of the drone itself of 2 to 3 cm is claimed by DJI,the actual accuracy of the drone RTK for positioning the images and for using it for mapping purposes without additional ground control is not known.To begin with,the actual GNSS RTK position of reference center(the physical point on the antenna)on the drone is not indicated,and uncertainty regarding this also exists among the professional user community.In this study the reference center was determined through a set of experiments using the dual frequency static Leica GNSS with RTK capability.The RTK positioning data from the drone were then used for direct georeferencing,and its results were evaluated.Test flights were carried out over a 70 x 70 m area with an altitude of 40 m above the ground,with a ground sampling distance of 1.3 cm.Evaluated against ground control points,the planimetric accuracy of direct georeferencing for the photogrammetric product ranged between 30 and 60 cm.Analysis of direct georeferencing results showed a time delay of up to 0.28 seconds between the drone GNSS RTK and camera image acquisition affecting direct georeferencing results.