The whole process of aerial photography took about 15 minutes.
Preliminary processing was carried out on the-site using a field notebook. We carried out Post-processing of GNSS measurements and photogrammetric processing with using the coordinates of the centers of images determined with a centimeter accuracy by the on-board GNSS receiver (Pic. 3). As a result points cloud (Pic. 4, 5,6) orthomosaic (Pic. 9 ). and DTM were created (Pic.8)
To assess the quality of data we used ground control points provided by the customer. The errors in plan and height were up to 8 cm and 15 cm, respectively. After focal distance calibrating with using at least one of the reference points, the accuracy in height was improved up to 8 cm.
Finally digital terrain model was created by automatic classification of the points cloud (Pic 7,8)
It should be noted that the resulting 3D model with 5 cm resolution corresponds to LIDAR data, and it is possible to classify vegetation, buildings, structures and other technological objects and create a detailed and accurate 3D terrain model.
The results of this projects fully meet the requirements of the customer and showed, on a practical example, the following advantages of unmanned aerial survey technology before using traditional methods:
— high accuracy and details
— high efficiency and productivity
— high percentage of automation of the processing
— low cost
— short terms of project implementation
