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 processing 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 eliminated 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 controls 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 inexperienced 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 management. 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 terrestrial 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 require 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 significant benefits. More are being discovered with every flight.
Is an autonomous flying laser scanner a good fit for your projects? These considerations can help you decide.
• What accuracy is required? Autonomous flying laser scanner technology captures data at plus or minus 1 to 2 cm, or .05 ft. If you need a quarter inch or better accuracy, you’ll want to use a terrestrial laser scanner for reality capture instead of or as a supplement to the aerial scan data.
• How quickly do you need the data? When productivity is paramount, an autonomous flying laser scanner is an order of magnitude faster than even the fastest terrestrial laser scanners.
• What are the site conditions? The autonomous operation of the technology provides significant safety benefits when capturing data in potentially hazardous situations.
• Are there airspace restrictions? Unlike other UAVs, which typically fly a few hundred feet off the ground for data capture, autonomous flying laser scanners operate within 25 feet of the structures being scanned. This proximity minimizes issues due to airspace restrictions. Built-in AirMap functionality lets you quickly check to see whether an airspace authorization is required.
• Is your project indoors or outdoors? Because the technology uses GNSS for navigation, it is limited to outdoor use. For projects requiring indoor data capture, consider using a robot-mounted autonomous solution or a handheld or stationary laser scanner instead.
• How much detail do you need? Capturing a point cloud with lidar gives you a higher level of detail than generating a point cloud from photogrammetry, especially for objects with vertical spacing. If your project requires a high level of detail, an autonomous flying laser scanner provides an advantage over other UAVs. (Explore sample datasets here.)
• What size is the project?
Because they fly at low altitudes, autonomous systems are not suitable for capturing large-scale topographic data. However, they are ideal for capturing smaller areas and structures where productivity, safety and detail are paramount.
• Is there a better way to capture the data?
Autonomous flying laser scanners might not be the best solution for every application—but they provide a distinct advantage compared to traditional UAV systems and, in some cases, terrestrial laser scanners. Whether used alone or in combination with other technologies, these full lidar UAVs make it fast and easy to scan inaccessible areas, stay safe on the site and capture all the data you need.
With their simple operation, impressive data quality and broad usability, autonomous flying laser scanners make it possible to harness the power of 3D digital data to deliver tremendous value. Finally, the vision of a UAV on every project is within reach.
To learn more about laser scanning and other solutions to maximize your surveying and engineering potential, get in touch with a surveying and engineering expert at Leica Geosystems.
Bryan Baker is the Unmanned Aircraft System (UAS) sales manager for Leica Geosystems in the US and Canada. He has been in the geospatial industry for his entire career and has a passion for aviation and technology. He’s an ASPRS certified mapping scientist, an instrument-rated commercial pilot, and a small UAS remote pilot. He’s also a factory-certified UAS trainer and an FAA Certified Flight Instructor. In his spare time, he volunteers as an FAA Safety Team representative and is a designated “Drone Pro” for the southwestern US. Bryan can be reached at firstname.lastname@example.org.