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    The ConTech revolution

    The construction industry is in the throes of its own digital transformation with new technologies changing and upgrading the way construction sites are managed from start to finish. Drones have been one of the biggest game changers and are now an integral part of the information-gathering and data collection stages of an infrastructure construction project.

    Using drones, sites can be surveyed from above as often as necessary. This makes it much easier to track progress as well as to identify any potential roadblocks or deviations from design before they pose a serious threat to either safety or the timeline of the project. However, drones do not build models of construction sites by themselves. They capture raw data which must be fed into a specialist system for creating 3D photogrammetry models.

    To create a survey-grade model and gather reliable data, contractors use ground control points (GCPs) that are associated with a precise known location.
    The biggest hindrance to the use of drones is the need to measure the GCPs’ geographic locations, and the huge amounts of time this process can take when done manually. In particular for large infrastructure projects like building new roads or highways, it can take hours for a surveyor to go out and place the GCPs in the right places, measure their geographic location, and then manually upload them to the mapping system and mark them one-by-one.

    This process has to be repeated each time the drones are sent out to collect data which, in some projects, can be as often as every day.

    Fortunately, the digital transformation of the construction industry continues apace, and with it comes new opportunities to use artificial intelligence (AI) and machine learning (ML). The introduction of Virtual Ground Control Points (vGCPs) will simplify the GCP marking and mapping process.

    Traditional use of ground control points for aerial mapping

    When a drone flies over a construction site, it takes pictures that will later be used to create a Digital As-Built replication of the site for planning and monitoring purposes. Ground control points provide anchor points that enable the map to be set in the right location and position. In order to produce a highly accurate model of a construction site, GCPs for aerial mapping need to be carefully distributed and measured throughout the site. Significant thought and planning goes into where the GCPs will be placed and whether they will need to be painted or if there is a pre-existing landmark that can be used. Typically, a site should have at least five GCPs to be mapped accurately, but larger sites can have many more than that. The surveyor who places the GCPs must be sure that they will be clearly visible from the air and will not be blocked by trees, buildings or other landmarks.

    Traditionally, the entire GCP process has been done manually. Once it is determined where the GCPs will go, a surveyor has to travel to the location and physically place them, keeping careful track of where each GCP is located and taking note of any characteristics of pre-existing landmarks that are being used. The location of each GCP must also be precisely measured using Real Time Kinematic (RTK) GPS in order to pinpoint the latitude, longitude and elevation of the exact center of the GCP. This information is then manually fed into the 3D photogrammetry system so that it can be used to create the model.

    To ensure that each new model is comparable and shares the same level of accuracy with each one that was previously created, the entire process must be repeated every time that a drone is sent to record a site. This can take hours, or even days, significantly delaying the progress of a project.

    As construction benefits increasingly from digitalization, the GCP process has remained manual and inefficient, which does not make sense. Virtual GCPs based on AI have the potential to change the story.

    Virtual ground control points – leveraging AI technology to automate the mapping process

    Datumate’s DatuBIM solution introduces the Virtual Ground Control Point (vGCP), an artificial intelligence based GCP that simplifies, minimizes, and almost completely eliminates the use of physical GCPs. This technology streamlines the entire procedure while retaining absolute precision.

    While there is no escaping the use of physical GCPs at the outset of a project, with an AI-based solution this only has to happen once, instead of each time the drone is sent up. This is where valuable hours of personnel time are saved.

    The initial setup involves laying out physical GCPs and manually measuring their locations. The DatuBIM AI engine automatically identifies the physical GCP marking structure and centerpoint. Beginning with the second flight, the DatuBIM’s Automatic Geo-Referencing (AGR) algorithm identifies features existing in both flights and creates a set of Virtual Ground Control Points. In every subsequent flight, a new set of vGCPs is created based on data gathered in the previous flight, eliminating any further use of physical GCPs. Of course, if physical GCPs (such as slabs of concrete that were initially used as GCPs) remain at the site, the AI engine will automatically take them into account.

    As noted, the Virtual Ground Control Point relies on the power of AI-driven Automatic Geo-Referencing and image processing algorithms. As soon as the DatuBIM system creates the 3D photogrammetry model of the construction site, it begins matching up images and features that it recognizes from previous flights. The more often flights occur, the more information the system can process and learn about the location, ensuring that the models take into account any changes to the terrain over time and remain enduringly accurate.

    In addition, DatuBIM automatically detects the Local Coordinate System without the need for any additional hardware or software. This means that regardless of the coordinate system used by the ground surveyor to take measurements with the GCPs, DatuBIM can detect the coordinate data type and apply it to each survey flight.

    The ConTech opportunity

    As the construction industry continues along this journey of digital transformation, there are tremendous opportunities for companies to streamline their processes, increase efficiency, and retain their competitive edge. Datumate’s Virtual Ground Control Point saves valuable time and money while maintaining the survey grade accuracy of construction site mapping and modeling.