Review of DJI Phantom 4 RTK for the Surveying Industry

Gruber, Gregory William John (2019) Review of DJI Phantom 4 RTK for the Surveying Industry. [USQ Project]

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Abstract

This report focuses on a very-small Remote Piloted Aircraft (RPA), the DJI Phantom 4 RTK, being a low-cost commercial grade Unmanned Aerial Vehicle (UAV). This UAV is considered for commercial application due to its integrated RTK GNSS receiver and high-resolution sensor. Research indicates the use of very-small RPA, in particular the DJI Phantom series, with the use of Ground Control Points (GCPs), may be suitable for photogrammetry.

To implement new technology into smaller organisations there is a requirement for economic benefit. Large organisations are currently utilising aerial photogrammetry to provide their client with large-scale surveys in a short duration of time. There is limited literature however with regards to a UAVs direct-cost and accuracy for surveying applications. The aim of this report is to provide a qualitative and quantitative analysis of the DJI Phantom 4 RTK to assist in determining its feasibility for implementation purposes.

This report investigates the background information required to understand photogrammetry properties to enable sufficient image correlation and to provide a method to successfully create a photogrammetric model of acceptable accuracy given mapping standards. The methodology prescribed has been implemented and results stated with discussions further identifying the limitations of application within the surveying industry. The tested applications have been further analysed against more traditional surveying methods to provide a direct-cost comparison and to identify differences in model accuracy.

It was found the UAVs pre-calibrated camera is insufficient for aerial photogrammetry due to focal shift. As a result, it was determined, the use of 2 GCPs is sufficient to constrain the cameras focal length during processing. From the geodetic control, at the 95% confidence level, the DJI Phantom 4 RTK is capable of producing a model to the limiting map accuracy of 1:100 with 0.1 m contours indicated. Upon further investigation, when directly comparing against more traditional surveying methods, the created Digital Elevation Models (DEMs) due to their spatial resolution contained significant error. The main errors were located in features of vertical and rigid nature.

Generally, when flying at altitudes of 60-80 m, it was possible to achieve a vertical accuracy of 0.05 m at the 95% confidence level from flat or sloped surfaces with a limiting map accuracy of 1:100 and 0.2 m contour interval. Suitable applications may include flood modelling, cut and fill diagrams of work-as-executed surveys and contour surveys. Where higher accuracy is required, design specifications should be higher or terrestrial survey may be required.

The main economic benefit of a UAVs use however is its ability to reduce the resources required to perform a task and to significantly reduce the risk of personal injury. This factor alone should not be overlooked when determining the associated costs and benefits of a UAV operation.


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Item Type: USQ Project
Item Status: Live Archive
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying (1 Jul 2013 - 31 Dec 2021)
Supervisors: Liu, Xiaoye
Qualification: Bachelor of Spatial Science (Honours) (Surveying)
Date Deposited: 18 Aug 2021 03:43
Last Modified: 26 Jun 2023 22:34
URI: https://sear.unisq.edu.au/id/eprint/43131

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