Unmanned aerial vehicles, also known as drones , entered our lives as hobby products and toys, and in a very short period of time they directly adapted to many different industrial systems. As a result, the surveying industry, which uses remote sensing methods frequently due to many professional fields, has also received its share from these technological toys.
In the world of drone, where we discover a new feature almost every day, we have examined RTK plugin which is one of the most critical features for surveyors. For this case study, we compared the asbuilt studies of a bridge project using UAV technology with and without RTK. If you still stay in between and can’t decide, reading this article will make your choice easier.
“Yes, there is a fact that almost all of us are aware that drone technology is an important turning point for the future of the surveying industry. The efficiency and profitability you receive will of course be directly proportional to how effectively you can use these devices.”
Summary of the Study
After the completion of the construction phase of the road projects, the project is put into service and transferred to the institution to operate. Although the road projects are manufactured in accordance with the approved design, due to the changes made during the construction, it is obligatory to produce as-built projects on the finished production before starting the operation phase.
In this context, a bridge project, ongoing construction in Istanbul, was conducted with the help of UAV. High resolution point data was created by establishing ground control points, the final product was compared with the existing project data and the basemap was created for drawing the corrected projects.
For a total area of approximately 1.5 hectares, a total of 6 minutes of flight was carried out at a height of 60 m, and 71 photographs of 1.8 cm / pixel ground sampling distance (GSD) were collected with 80% transverse to longitudinal overlap rates. The UAV’s camera is then set to take pictures every two seconds, and a total of 650 photographs were taken by performing movements on a designated line which is an approximate distance of 10 m from details of beams, columns, wall surfaces.
After the image processing step, the required cross-sections were taken with the help of the 3D point cloud obtained and asbuilt studies could be performed on it. These studies clearly show that it is possible to produce basemaps with sufficient accuracy on the final products made with unmanned aerial vehicles.
Using RTK, you can measure even in the most demanding locations. In addition to the variety of areas where you can measure with RTK, you can take advantage of such issues as measuring time, equipment need.
Although you do not need ground control points when measuring with RTK, it can continue to be used as a confirmation of the studies. The results of the research show that it is possible to get very close results with both UAVs with and without RTK. Therefore, the establishment of ground control points is no longer a necessity.
3D Bridge Model Obtained from 40 million Points
We would like to thank Hasan Bora Yavuz, İdris Gökdemir, Utku Arslan and Emrah Erdem Özlü who shared his master thesis on “Use of New Technologies in Highway Projects”.
We would like to thank the GNSS Teknik family for their support in the preparation and implementation of this study.