NEXT GENERATION MAPPING – SAVING TIME IN CONSTRUCTION SURVEYING WITH DRONES
STRABAG Deploys the Phantom 4 RTK for Construction Surveying to Create Precise 3D Models
The European highway network stretches across 80,000 km and multiple countries. In 2017, Germany ranked second in Europe and forth globally with 12,996 km of highways, making Germany a main transit country for millions of passenger cars and trucks on their way to destinations in Eastern or Southern Europe, creating heavy stress on the existing structures.
STRABAG – Specialists in Roadwork Construction
Executing the Ministry’s plan is a challenging venture that requires long term planning and coordination of private sector firms and specialists to complete these large scale roadwork construction projects.
STRABAG SE, Europe’s sixth largest construction group, and its German subsidiary STRABAG AG are major players in transport infrastructure construction, which accounts for 37% of STRABAGs output volume. With over 100 years of experience and 70,000+ employees globally, STRABAG has deserved its top market position for good reasons. One is staying ahead on technological innovation.
Drone data can accelerate work progress on construction sites
With drones, STRABAG is able to create more detailed 3D models in less time
DJI Phantom 4 RTK – A Game Changer for Construction Surveying
Built for Surveyors
Without GCPs, the achievable horizontal accuracy is up to 3cm and vertical accuracy up to 5 cm within the global WGS84 reference network used by the Phantom 4 RTK. In areas that lack mobile network coverage the Phantom 4 RTK allows surveyors to use PPK for subsequent evaluation while keeping the same accuracy provided by RTK.
“When setting up the flight path, we need to select the altitude and overlap. The P4R provides an integrated flight planning app in the remote control including all relevant surveying parameters to make the flight planning easy and efficient,” says Philipp Mielke, Teamleader Business Unit Digital Object Survey and UAV at STRABAG.
The built-in flight planning app simplifies the setting of operational parameters
The Phantom 4 RTK was built to make drone mapping easy, convenient and efficient with the ability to fly for up to 30 minutes, letting users map a large area in one flight. Even if the area is too large to map on a single battery charge, the Operation Resumption function of the GS RTK App automatically resumes the mission after the battery has been replaced. The Phantom 4 RTK saves mappers even more time by flying the mapping plan with curved edges and turning while maintaining a consistent speed. The ability to fly at a consistent height across complex terrain and specific corridor mapping functions are big improvements for surveyors. DJI Mobile SDK enables these features.
If battery change is required for larger mappings, the Phantom 4 RTK resumes the mission automatically
Captured data can easily be integrated into third-party photogrammetry software, delivering industry acceptable point clouds and 3D-models. Philipp Mielke emphasizes that “solutions to upload the drone data from an on-site laptop to the cloud for processing are another step to make on-site surveying innovative. It makes surveyors independent of geographical distances between construction site and their office to permit immediate and powerful data processing.” Visualizing the 3D-model in the cloud shortly after the data was captured allows engineers on site to review the construction work and initialize next steps.
Due to the highly detailed and comprehensive survey data, surveyors and CAD technicians can be sure that they gather all the data in one go without having to return to the construction site to collect additional information, thus saving time. After processing the 3D point cloud from the captured drone photos, the data is post-processed according to the individual project requirements. Typical initial workflows include classification of the point cloud for filtering out unwanted objects such as vegetation, vehicles and artificial objects, feature vectorization and extraction. The processed data is then used for digital terrain and surface modelling, mass and volume calculations, and building information modelling (BIM).
Once processed the Phantom 4 RTK image data can be used to create a variety of deliverables:
In addition to 3D deliverables, 2D orthophotos can be created with third-party software to provide excellent overviews of large construction sites from a bird’s eye view. Both 2D and 3D data is also a good base for pioneering project meetings, driving regular coordination and project reviews.
Drones - Digitizing the Constuction Industry
Drone generated 3D models offer a variety of analysis and evaluation options. Depending on the required accuracy the most common use cases are surveying, inspection, documentation and construction progress monitoring. All of the above are accomplished with drones at the Würzburg construction site.
“STRABAG seeks to expand drone usage for construction projects globally. We currently employ 170 surveyors in Germany and 300 all over Europe. The new DJI Phantom 4 RTK is an easy-to-use and versatile drone with integrated RTK network functionalities. This combination will allow STRABAG to equip more teams with drones to make construction surveying workflows quicker and more efficient,“ Thomas Gröninger summarizes. “The DJI Phantom 4 RTK is an essential addition to the tool box of the surveyor and will take a major role in the process of digitalizing the construction industry.”