A Comparative Study on UAV Photogrammetry

Hager, Marcus Timothy (2017) A Comparative Study on UAV Photogrammetry. [USQ Project]


Abstract

The science of photogrammetry has long been a recognized tool in the spatial science industry. For a long time, large or complex areas have been surveyed by aerial photogrammetry. Over the recent years with the introduction of small, cheap, Unmanned Aerial Systems (UAS), a question remains, with the same general fundamental ingredients, a camera and an aircraft, can we achieve the same accuracy with these systems?

This paper focuses on a comparison of accuracy between industry standard aerial photogrammetry data and UAS photogrammetry data from a DJI Phantom 4 Drone. These systems are generally used in photographic application and are therefore quite in expensive. The systems however contain the essential characteristics to any successful photogrammetry survey that being the payload (camera), the aircraft and the ability to plan a mission to allow for the suitable overlap required to produce the 3d measurable model.

A confidence interval or level can be calculated from the experiments accuracy using statistics. The paper will replicate part of the aerial survey and compare both sets of data to a suitable control to work the Root Mean Square Error in the Distance (2d) and Height (1d) for each set of data. Ideally with the correct mission planning the surveys should have similar levels of confidence in accuracy.

These UAS systems are set to change the way surveyors deliver data. These systems are considerably cheaper than industry standard systems and aerial surveys. Levels of confidence in accuracy have found these systems to be as accurate as these other systems in normal working conditions in this report. There are surveys too large or complex for UAS like the DJI Phantom 4 but I would recommend it could be used on projects that require an accuracy of +/- 50mm and not too large that battery life becomes a burden on the survey. I recommend a flight height of 40-60m to achieve this accuracy with this UAS due to pixel size. It is noted that the heights near objects of sharp change such as roads near tall fences, trees, buildings, etc. require careful processing to ensure heights are not distorted due to these structures. A 1 is to 1 ratio was found where if the fence is 2m tall, the heights were found to be correct 2m away (without corrective processing).

Although the results of this project satisfied the aim of this project, it is recognized that these results can be improved by alternative methods mentioned in the discussion section of the report and as well as number of recommendations for future research to better understand the limitations of these systems in providing spatial data.


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Item Type: USQ Project
Item Status: Live Archive
Additional Information: Bachelor of Spatial Science (Honours)(Surveying)
Faculty/School / Institute/Centre: Current - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying (1 Jul 2013 -)
Faculty/School / Institute/Centre: Current - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying (1 Jul 2013 -)
Supervisors: Liu, Xiaoye
Date Deposited: 10 Sep 2021 04:59
Last Modified: 10 Sep 2021 04:59
URI: http://eprints.usq.edu.au/id/eprint/40810

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