Abstract
Abstract. Unmanned Aerial Vehicles (UAV) are established platforms for photogrammetric surveys in remote areas. They are lightweight, easy to operate and can allow access to remote sites otherwise difficult (or impossible) to be surveyed with other techniques. Very good accuracy can be obtained also with low-cost UAV platforms as far as a reliable ground control is provided. However, placing ground control points (GCP) in these contexts is time consuming and requires accessibility that, in some cases, can be troublesome. RTK-capable UAV platforms are now available at reasonable costs and can overcome most of these problems, requiring just few (or none at all) GCP and still obtaining accurate results. The paper will present a set of experiments performed in cooperation with ARPA VdA (the Environmental Protection Agency of Valle d’Aosta region, Italy) on a test site in the Italian Alps using a Dji Phantom 4 RTK platform. Its goals are: a) compare accuracies obtainable with different calibration procedures (pre- or on-the-job/self-calibration); b) evaluate the accuracy improvements using different number of GCP when the site allows for it; and c) compare alternative positioning modes for camera projection centres determination, (Network RTK, RTK, Post Processing Kinematic and Single Point Positioning).
Highlights
1.1 UAV surveys in mountain areasUnmanned Aerial Vehicles (UAV), easy to operate and lightweight enough to be carried on the spot on foot, are established platforms for photogrammetric surveys for agencies in charge of environmental monitoring in mountain regions or remote areas
380 x 530 m wide while the actual extent controlled by check points (CP) is smaller: about 330x330 m wide
Nineteen high visibility targets of 50x50 cm size have been deployed over the area and measured twice with a Leica GS16 in RTK mode with respect to a Geomax Zenith 35 Pro set over a reference point determined in ETRF2000(2008) coordinates with respect to the CORS regional network
Summary
Unmanned Aerial Vehicles (UAV), easy to operate and lightweight enough to be carried on the spot on foot, are established platforms for photogrammetric surveys for agencies in charge of environmental monitoring in mountain regions or remote areas. As far as some basic aerial photogrammetry rules are correctly employed, very good accuracy can be obtained with low and middle-cost UAV platform. Though providing Ground Control Points (GCP) according to traditional aerial photogrammetry rules, significant systematic deformations show up in the ground coordinates. Providing a good ground control network can limit significantly these effects and improves drastically the final quality of the survey. Many authors in the recent past investigated thoroughly the influence of GCP number and spatial distribution on the accuracy of the photogrammetric reconstruction, both addressing operational case studies, e.g. Many authors in the recent past investigated thoroughly the influence of GCP number and spatial distribution on the accuracy of the photogrammetric reconstruction, both addressing operational case studies, e.g. (Gindraux et al, 2017), (Tonkin and Midgley, 2016), (James et al, 2017 a) and numerical simulations (James et al, 2017 b)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
