Select Test Area
A test area has been selected, outside of No Flying zone of airports (pic.1). The area was about 110 000 sq. m. (11 hectares), covered by only one battery for every flight altitude ranging from 60/100/150 meters.
Set up check points & base station
The Check Points have been placed and measured in RTK mode by second REACH RS+ (Rover) in evenly distributed manner throughout the test area to establish the check control points.
Flight Mission & Aerial Image Acquisition
Three missions were planned at 60, 100, 150 meters’ altitude with 85% along and 70 % across overlapping, flights were performed with up to 9 m/s speed.
- After all the flights, set of raw images and raw GNSS data were downloaded from the drone and the base station.
- The data was converted into Rinex format and post processed by RTKLIB application and as a result precise coordinates of images exposure were received that were further embedded to photos by TOPOSETTER application.
- Datasets from different flight altitudes, i.e. 60, 100, 150 respectively were photogrammetrically processed by Photoscan software without using any Ground Control Points.
- After processing, the checkpoints coordinates were imported into the Photoscan project and checked for the accuracy of each flight.
- The data has also been checked into Traditional Stereo Photogrammetry workstation and the result was found well within 3-4 CM accuracy.
- In all the Missions, the results were well within 3-4 CM Accuracy.
Tables for the result against the GCP’s
The above results from flights of different altitudes, show that the accuracies achieved are well within two pixel of GSD and hence passes the criteria of the National Standard for Spatial Data Accuracy (NSSDA). The outcomes so achieved have taken drone photogrammetry to new heights.