The project aimed at detailed scanning and mapping of the Roșia Poieni Quarry, its spillway and the Geamăna tailings pond, using LiDAR technology to obtain accurate and high resolution data for the entire 865 ha area.
Image 1 – Areas of interest
The process was carried out in two stages as follows:
Phase 1: DSM generation
In the first stage, we generated a Digital Surface Model (DSM), which served as the basis for future LiDAR sensor flights. The goal was to maintain a constant altitude above the ground, thus ensuring a uniform density of points in the resulting point cloud especially given differences in elevation above 600m.
- Team 1 was responsible for scanning the quarry and the spill, simultaneously using two DJI Mavic 3 Enterprise drones equipped with 20 MP cameras. The flight plans were created in the DJI Pilot 2 application, using the real-time following function, which allows a constant distance to the ground to be maintained by optical sensors integrated in the drones. This contributed to a high-quality DSM.
- The one-person Team 2 managed the scanning of the Geamăna settling pond, using a DJI M350 RTK drone equipped with a 45 MP DJI Zenmuse P1 45 MP sensor. The flight plan was also realized through the DJI Pilot 2 application, using the satellite DSM import function. This method allowed a constant distance to the ground to be maintained, using a DSM generated from satellite imagery that was accurate enough to serve as the basis for subsequent LiDAR flights.
In the first phase, over 6000 images were captured over 32 flights in a single day.
Phase 2: LiDAR data capture
After capturing the raw data for the DSM, it was processed on the same day, using a workstation to generate the final DSMs, which formed the basis for the LiDAR data capture.
Universal Ground Control Software (UgCS) flight planning software was used to capture the LiDAR data.
Image 2 – LiDAR flight mission based on previously generated DSM from the drone
The previously generated DSMs were imported into UgCS and served as the basis for all flight plans, either for the Roșia Poieni Quarry, the spillway, or the Geamăna tailings pond.
Data collection was carried out using the YellowScan Surveyor Ultra system, which utilizes LiDAR technology to collect high point density data essential for detailed mapping of large areas. With a 360° field of view, this system can collect 640,000 points per second in a single echo and has the ability to record up to three echoes, making it particularly effective in difficult areas such as forested areas. This feature ensures complete and detailed coverage and fast data processing. Surveyor Ultra offers 3.0 cm accuracy and 2.5 cm precision, making it ideal for applications that require extremely precise measurements.
The LiDAR sensor has been mounted on the Hexadrone Tundra 2 professional drone, known for its ruggedness and modularity, designed to handle the most demanding missions. The drone can carry a payload of up to 8 kg thanks to the ability to quickly change arms, which enabled a flight time of up to 42 minutes when equipped with LiDAR for this project. The Tundra 2 is equipped with the terrain following function, essential for maintaining a constant altitude above the ground using the previously generated DSM. Designed to withstand dust and water (to IP54 standard) and tested for the harshest conditions, the Tundra 2 offers reliability and performance, being UAF certified and used even by the French military. In less than 3 minutes, the drone can be set up and ready to use, its transportation is made easy thanks to a special backpack developed in collaboration with the French special forces or a Pelicase-type protective case.
Figure 3 – Colored point cloud, Quarry
In the second stage, 649GB of data were generated over 17 flights resulting in a point cloud (digital model) consisting of 3,541,723,963 (yes, 3.5 billion) points.
