In June 2019, one of our pro-users International Forestry Natural Resources Institute Finland (Luke) ran some accuracy tests of DJI MAVIC 2 PPK upgraded by Topodrone team.
Luke conducted aerial survey in Joensuu city, Finland using DJI MAVIC 2 with additionally installed EMLID Reach M+ GNSS receiver on board and EMLID REACH RS+ as a base station.
The goal was to create a detailed 3D model and an orthomosaic without using ground control points for aerial triangulation and check the accuracy of the model by comparing with already measured check points on the ground.
Before flights 8 ground control points (GCPs) were set at the test site. All GCPs were captured with a Reach RS+ rover. Corrections were acquired from an RS+ base in RTK mode.
Pic. 1 Area of interest, GCPs location (blue croses)
Pic. 2 Processing in RTKLIB
Then survey mission was prepared in PIX4D capture app, double grid mission with 80 % front and side overlapping at 80 miters altitude was setup. Than aerial survey was performed, whole process took less than twenty minutes, at the same time REACH RS+ base station was collecting raw GNSS data for further processing. Pic.1
After flight, raw logs from the drone and base station were downloaded and post-processed using the geospatial analysis RTK LIB and TOPOSETTER software. This was done in order to get precise x,y,z position of each photo. Pic.2
At the next step, institute engineers imported images captured by the drone together with the list of accurate photos coordinates to PIX4D software.
Photogrammetry processing in PIX4D software did not take a lot of time and was made totally in automatic mode, only precise position of images location were used for aerial triangulation.
Once initial processing step of block triangulation was done, eight ground control points were imported to the project to check accuracy. Total RMS error was no more than 3 cm. You can see results against GCPs in Tab.1
Pic. 3 Pix4D data processing
Please follow the link to download the full Pix4D report.
Tab. 1. Pix4D accuracy report
Finally 3D points cloud was generated together with automatic classification.
"There is a great advantage in using DJI MAVIC 2 PPK upgraded by Topodrone team. Reach M+ connected by Topodrone synchronization system with 20 Mp camera for capturing photo events with centimeter level accuracy converts DJI MAVIC 2 Pro drone to an affordable professional survey tool. It allows us to spend fewer man-hours than on a traditional survey, now we don’t need to lay GCPs And because of optimizing the resources of the team, we can deliver the best quality data to our clients promptly. What I also would like to add about DJI MAVIC 2 PPK is that it’s very easy to configure and use." — Eugene Lopatin, Senior Researcher, International Forestry Natural Resources Institute Finland (Luke)
TOPODRONE SA is an official partner of PIX4D
REGION RESELLER OF TOPODRONE PRODUCTS IN FINLAND FORGIS OY
Pic.4 3D model
