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Drone Autonomy for Bridge Inspection. The Newest Tool on the Inspector’s Belt.

A Skydio 2 inspecting the underside of a bridge

Snooper trucks are expensive and dangerous

A tipped-over snooper truck endangers two inspectors mid-inspection

Drones are the clear solution

Source: AASHTO

What to look for in a drone for bridge inspections

Manual drones don’t get the job done

  • They crash. Any manual drone pilot can attest to the nervous, white-knuckle flight experience on a manual drone. Collisions are expensive, and the consequences of a collision can be severe enough to ground an entire drone program. YouTube is littered with unfortunate crash montages for DJI drones, yet to any enterprise drone operator, this is not a risk they can afford. Bridges are often over water (risks your drone) or roads (risks civilians below), and are a particularly bad environment for drones to fall out of the sky.
  • They are fully dependent on GPS and magnetometers. Under a bridge, surrounded by metal trusses, the drone can depend on neither, and cannot hold its position without constant operator input. Combine that with the fact that the most common enterprise drones, the DJI Phantom and Matrice series, are fully dependent on GPS and Magnetometers, and the obstacle-rich, GPS-denied underside of a bridge is an extremely dangerous place to fly.
  • They cannot fly up close. Because it’s so hard to keep a manual drone from crashing, inspection protocols with manual drones call for long stand-off distances to increase the pilot’s margin for error. This results in worse data, so teams have to pay more and more for increasingly expensive cameras in a fruitless quest to capture high-resolution imagery. As a result, DJI Matrice pilots invest tens of thousands of dollars in cameras like the $14,000 DJI Zenmuse XT2, which has the high resolution required to compensate for flying far away.
  • They cannot look up. Most manual drones were not designed for enterprise-level applications, so they have a limited gimbal tilt. More specifically, they cannot look straight up to inspect the underbelly of bridges. The Mavic 2 Enterprise’s gimbal, for example, is mounted on the bottom, and has no way to look up. The DJI Matrice series forces operators to choose whether to mount their gimbal on top or bottom, or sacrifice battery life (and their budget) to mount two sensors at once.

Skydio solutions for bridge inspection: Skydio 2, Autonomy and 3D Scan Turn drones from niche tools to full-on industrial automation

Autonomy is the path to automated inspection

  • It’s the bottom that matters. Today’s modeling software, such as Pix4Dcapture, is designed to script out a lawnmower-pattern flight from above the subject of interest. However, this isn’t much use for bridge inspectors, who often care more about the sides and bottom of the bridge.
  • Bridges are hard to fully cover manually. Pilots need to make sure they have full coverage of overlapping photos for every surface of a bridge to generate a 3D model. On enormous bridges, this is nearly impossible to achieve, especially across multiple batteries. So, bridge inspectors take thousands of photos, which leads to hours of processing time to generate 3D models, and piles of full hard drives or cloud storage bills.



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