C+S July 2022 Vol. 8 Issue 7 (web)

UAVs and the New Autonomous Reality Autonomous flying laser scanners bring fast, complete reality capture within reach for everyone By Bryan Baker

A drone on every project site to capture all the as-built data—that was the vision six or seven years ago, when UAVs first took to the skies. That dream, like so many of the early UAVs, didn’t stay airborne for long. The complexity of becoming licensed, operating the aircraft and process - ing the photogrammetric data proved too unwieldy for many surveying, engineering, and construction firms. And so, while the idea of UAVs has continued to expand, the reality has fallen short—until now. The advent of autonomous flying laser scanners changes everything. Using advanced sensor fusion technology that combines LiDAR simultaneous localization and mapping (SLAM), visual SLAM, radar, and GNSS, the newest systems enable accurate and complete reality capture from the air without operator guidance. And that’s just the beginning. A Transformative Shift in UAV Technology While an FAA Part 107 Remote Pilot certification is still required in the U.S. to fly the latest autonomous solutions, these systems have elimi - nated the complexity of data capture and processing. Instead of the hours of training and practice required to create flight plans and use a joystick for UAV navigation, the drone does all the work. Simply define your scanning area on the tablet screen, press a button, and the system creates its own flight plan, collects the data, and avoids obstacles. Through the tablet interface, you see what the drone sees. Gesture con - trols make it easy to capture all the data. Double tap anywhere on the screen, and the drone flies in that direction. Swipe left, and the drone rotates left; swipe right, and it rotates right. Pinch to zoom in or out, and the drone flies backward or forward—all with complete awareness of its surroundings because it is mapping its own environment as it flies. Fast and smart, it flies up and over obstacles, capturing all the data in front and behind in a single pass. Since it captures everything as a point cloud, there’s no need to convert the data when it’s finished. And unlike photogrammetry, which can’t resolve the depth difference for smaller objects spaced vertically such as pipes, railings, and stairways, lidar data provides a measurable level of detail on all objects. As a result, it’s now possible for an inexperi - enced operator to capture in minutes what a highly skilled specialist and a team of processing experts might spend hours or even days trying to acquire with manually operated, photogrammetry-based systems. The implications for projects requiring fast, safe, comprehensive data capture are remarkable.

Proven Advantages in Speed, Safety and Data Completeness In the installation of large duct banks, documenting the precise location of the conduit before concrete is poured is imperative for asset manage - ment. The fastest, most advanced approach to digitally document these assets has been to use a high-speed terrestrial laser scanner, which can capture a 1,000-ft-long duct bank in about half a day. However, even with multiple setups from both sides of the duct bank, a stationary ter - restrial laser scanner can miss data from the sides and bottom of the trench in areas that are not within the line of sight of the laser scanner. An autonomous flying laser captures the entire trench in minutes with complete data. This approach accelerates the completion of duct banks and subsequent construction while providing an accurate and complete digital record of the assets. At oil and gas refineries, an autonomous flying laser scanner quickly and easily captures the tops of cooling towers along with details such as pipe racks, staircases and power lines. This data can be used for 3D asset management or modeling new piping for best fit. In building documentation, the technology quickly captures the entire façade of a multistory building, including balconies, window recesses, the tops of architectural details, and the roof—details that would re - quire multiple setups and significantly more time using a terrestrial laser scanner. Bridges, dams and other structures requiring measurement data and condition assessment also benefit from the advantages of autonomous flying systems. The ability to capture accurate, complete point cloud data on the tops and sides of structures without putting an operator in harm’s way creates new opportunities to augment documentation and monitoring projects with rich 3D data and enhanced visualizations. These are just a few examples of applications where the efficiency, safety and data collection capabilities of the technology provide sig- nificant benefits. More are being discovered with every flight. Key Considerations Is an autonomous flying laser scanner a good fit for your projects? These considerations can help you decide.

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July 2022 csengineermag.com

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