Overview

Green Sky was engaged by a client to conduct a survey of approx. 36ha of land in Queensland. The purpose of the survey was to capture high-accuracy data for land planning purposes as well as inspecting areas that were inaccessible due to poor terrain access. Green Sky used the DJI M300 RTK with DJI L1 drone for the survey. Two EMLID RS2+ GNSS receivers were used; one was used as a base station and the other as a rover to lay many ground control points (GCPs) The survey required the use of PPK (post-processed kinematic) to achieve an accuracy of 5cm.

Challenge

The main challenge of the project was to capture high-accuracy data over a large area of land, while also producing a 3D model that showed accurate contours for land planning. The location of the site also presented challenges, as it was in a remote area without reliable mobile coverage, as well as difficult and hard to reach areas.

Process

Green Sky worked closely with the landowner to define the deliverables required for the project. Prior to the flight operation, we confirmed the land boundary with the owner via a KML to ensure complete site coverage. Green Sky set up the EMLID RS2+ as a base station. GCP’s were placed throughout the parcel of land at different locations and elevations with the EMLID R2S+ rover. In the DJI M300 drone remote, the terrain follow mode were activated and a flight altitude of 50m AGL was selected. 3 different take off/landing locations were required to maintain visual line of sight (VLOS) throughout the drone flight.
To process the surveying data, we used specialized cloud software that allowed us to create and share a 3D model representing the land's contours accurately. Since we couldn't use RTK, we relied on PPK to achieve centimetre-level accuracy. This technique involved using two EMLID RS2+ GNSS receivers, with one acting as a base station and the other as a rover. The resulting data was then post-processed using PPK to ensure the highest possible accuracy.

Result

The data captured by Green Sky was provided to the client in the form of high-resolution photos, LiDAR data, and a 3D model of the land. The client was able to use the data for land planning purposes and to make informed decisions about the development of the land. The use of ground control points and PPK ensured that the data was accurate to within a few centimeters, which was crucial for the planning and development of the site.

Conclusion

Green Sky was able to overcome the challenges of capturing high-accuracy data over a large area of land, while also producing a 3D model that accurately represented the contours of the land. The use of the DJI L1 drone and ground control points, combined with post-processing using specialized software and PPK, ensured that the data was accurate to within the required 5cm. The client was ecstatic with the results and was able to use the data for land planning purposes.

Output

Green Sky provided the client with high-resolution photos, LiDAR data, and a 3D model of the land. The data was used for land planning purposes and to make informed decisions about the development of the land. The use of ground control points and PPK ensured that the data was accurate to within 5cm, which was crucial for the planning and development of the site.