TOPODRONE team introduces its latest development TOPODRONE DJI Air 2S PPK - the most affordable survey drone on the market, equipped with a 20 Mp camera and a high-precision survey grade GNSS receiver on board.
TOPODRONE DJI Air 2S PPK is the most compact survey drone on the market today, providing high quality imagery with 20MP resolution, automatic flight mission planning, and up to 22 minutes of flight time.
L1/L2 GPS, GLONASS, Galileo, Beidou GNSS receiver is installed onboard TOPODRONE DJI Air 2S PPK and works in PPK (Post Processing Kinematic) mode. The unique synchronization system between DJI camera and TOPODRONE PPK equipment allows without any delay and distortion determines the moment of taking photos that provides 3-5 cm XYZ accuracy of orthophoto and 3D point cloud at distances up to 20 km from the base station.
The TOPODRONE DJI Air 2S PPK is small, foldable fits into a small case or bag, and comes with an extra set of batteries, car charger, and spare propellers.
Survey drone comes bundled with one of the most powerful TOPODRONE Post Processing software, which performs:
- Static and kinematic post processing.
- Automatic alignment of high-precision coordinates after post processing with imagery and saving them to EXIF tags.
- Support of all possible coordinate systems and geoids.
To evaluate the accuracy of the data obtained with TOPODRONE DJI Air 2S PPK we offer you the project of the aerial survey of the urban area, where more than 20 ground control points (GCPs) were measured evenly distributed over the whole work area.
Fig. 1. Collecting GCPs with EMLID Reach RS2.
Fig. 2. Check points location.
Dronelink mission planning software was used to prepare the survey mission and control the drone.
Fig. 3. Mission planning in Dronelink app.
Aerial survey was performed along the double grid route with a front and side overlap of 75% and 80%, respectively, from a height of 60 meters and a speed of 5 m/s.
After the mission, Rinex files from the Swipos VRS network at 1 Hz were downloaded.
Fig. 4. VRS base location.
The TOPODRONE Post Processing software was used for calculating precision coordinates and georeferencing of the images.
TOPODRONE Post Processing workflow is quite simple. We need to select a folder with images, download ubx file from TOPODRONE PPK equipment, set the offset of the antenna relative to the camera and download the Rinex file from the base station. Before starting the calculation you can select any coordinate system and GEOID.
We would like to pay your attention to the significantly increased speed of post processing.
It should be noted that in the new version of the software the function of graphic matching of coordinates and images is also very convenient and clear.
Fig. 5. TOPODRONE Post Processing software. The software supports great variety of any kind of geoid and coordinate system.
Fig. 6. TOPODRONE Post Processing software. Graphical interface of matching coordinates of images and photos.
After post-processing step, we got a set of images with high-precision coordinates recorded in the EXIF tags and immediately loaded them into the photogrammetric software 3Dsurvey and Agisoft Metashape.
As you know, this software has great algorithms for aerial triangulation and for removing rolling shutter camera distortions.
You can read more about this in one of our previous articles.
Fig. 7. Drone photos processing.
After performing block alignment, removing distortions caused by the rolling shutter, and focal length calibrating, we downloaded the coordinates of more than 20 GCPs evenly located across the survey area and made an accuracy assessment.
The results of comparing the control points with their locations on the images are shown in table.
Fig. 8. Accuracy report.
As you can see from the table, the errors of the control points are within 1-5 cm in XYZ position.
These outstanding results were achieved without using of any GCPs on stage of drone photos block adjustment.
Next the detailed point cloud was generated and finally 3D positions of control points were compared to the high detailed point cloud.
Fig. 9. Highly detailed point cloud.
Fig. 10. Points cloud shows poles, fences, trees, road signs buildings and structures.
Fig. 11. Points cloud shows poles, fences, trees, road signs buildings and structures.
Fig. 12. Location of checkpoints.
Fig. 13. Location of checkpoints.
Fig. 14. Location of checkpoints.
Fig. 15. Location of checkpoints.
With the outstanding results obtained in this test, we can confidently declare that TOPODRONE DJI Air 2S PPK is the most affordable surveying drone on the market powered by a 20 Mp camera and survey grade GNSS receiver providing reliable horizontal and vertical accuracy within 3-5 cm for both orthophoto and point cloud.
We can positively say that TOPODRONE DJI Air 2S PPK brings a new era of affordable mapping drones with all the necessary features of professional survey UAVs, such as high accuracy, automatic obstacle avoiding, user-friendly mission planning app and powerful post processing software.
At the meantime we invite you to review for yourself the quality of the orthophoto and point cloud obtained by TOPODRONE DJI Air 2S PPK.