DRMP combines data from the mdLiDAR3000, mobile and terrestrial LiDAR to quickly create accurate point clouds.
by Renee Knight
As seen in the June/July 2021 Issue of Inside Unmanned Systems
When the team at DRMP Inc. first invested in UAS in 2016, it was because they needed an innovative approach for a challenging project. They were tasked with creating a design level topo of the runway and taxiways at Ascension Island, an isolated volcanic island in the middle of the Atlantic Ocean. The fixed-wing solution they purchased allowed them to quickly complete the mission, and the drone program took off from there.
The Orlando-headquartered company, which provides civil infrastructure services, progressed to rotary drones and eventually decided to start flying a LiDAR payload, Charlotte Surveying/Geospatial Manager August Thick said from DRMP's Charlotte, N.C., location. They already used terrestrial and mobile scanners, so it just made sense to add drone-based LiDAR to the mix. And after doing their research, it was clear the mdLiDAR3000 from Microdrones was the best fit.
“All of our terrestrial and mobile scanners are Riegl, so we were drawn to the Microdrones system because we could equip it with the miniVUX2UAV,” Thick said. “We also liked that it was a complete solution. We didn’t have to build a system and try to make everything fit. It was already retrofitted to the scanner and all the offsets were calculated. The fact it’s built in Canada and not in China is also a benefit, as we do a lot of federal jobs that don’t allow us to use Chinese-made drones.”
“ALL OF OUR TERRESTRIAL AND MOBILE SCANNERS are Riegl, so we were drawn to the Microdrones system because we could equip it with the miniVUX-3UAV. We also liked that it was a complete solution.”August Thick, Charlotte Surveying/Geospatial Manager, DRMP
DRMP invested in the mdLiDAR3000 about a year ago, and the team typically flies the system once a week or even more for bigger projects, Thick said. They combine the drone-collected LiDAR data with their mobile and terrestrial LiDAR solutions, which has proven to be a significant time saver.
One of those projects involved flying 6.5 miles of Florida state Road 538 for a widening project, Thick said. The mobile system scanned the actual roadway, and that data was supplemented with the drone LiDAR data.
“We used the drone for basically everything that wasn’t pavement, so ditches, the ground beyond the ditches, fences, powerlines—anything we needed for a design level topo,” he said. “If we would have done that conventionally it would have probably taken triple the amount of time. We basically set targets and flew all that in two or three days. If we did that conventionally it would have taken two to three weeks.”
After the flights, point clouds from both solutions were combined into one big point cloud, Thick said, and then put into a program called topoDOT, a point cloud CAD software for 3D maps and models, to create the final deliverable.
The user friendly mdInfinity software from Microdrones was used to create the initial point cloud, Thick said, a fast, easy process.
DRMP deployed the system to gather the information needed to obtain permits for a landfill expansion in Florida, Thick said, as an example of another application. They flew the new site, which was about 100 acres, in a day, a project that normally would have taken as long as a week and a half.
The mdLiDAR3000 also was deployed in Osceola County, Florida, for a different type of expansion, this one a road corridor. The objective was to create a new roadway design, extending the dead-end road 3,000 feet to meet up with another dead-end road to make it one pass through.
“It was a mix of cow fields and open woods, so it was perfect for a LiDAR drone mission,” Thick said. “There were no obstructions, and it was a quick, easy job to do with a drone. It really saved time; we flew that entire job in a day.”
Not only does the drone offer significant time savings, it also provides the accuracy DRMP needs while giving them updated imagery to use along with the data, Thick said.
“It’s just as accurate as traditional methods,” he said. “The accuracy we’re getting raw is around, .10 horizontally and .15 vertically. The targets check so well we really wouldn’t need to waste time on adjustments if it’s strictly groundwork, although we still typically adjust for the little bit of extra accuracy. If you’re getting a shot on the ground conventionally, the rod can sink down that much if you’re not careful. So, if you’re hitting targets in that range, it’s a good indicator the data is really good.”
The team has been happy with the time savings and the accuracy the system provides and is looking into other ways to use the technology, Thick said. One of those is stockpile volume calculations on construction sites, something the system can handle much faster than ground crews.
“Contractors get paid by how much dirt they bring in or take out,” Thick said. “Drones are so much more accurate calculating that because instead of crews getting data every 100 feet, the drone gets data from everywhere.”
They also plan to use the mdLiDAR3000 to fly the landslides that occur each year in the mountainous regions of North Carolina, Thick said, a task they’ve been handling with other UAS. With the mdLiDAR3000, they won’t have to set out nearly as many targets because LiDAR requires fewer adjustments than photogrammetry, making the missions more efficient and safer.
The team continues to look for new use cases and ways to incorporate the mdLiDAR3000 into projects, Thick said.
“We’ve gotten comfortable with what we’re seeing out of the system and the consistency of the accuracy we get day to day,” he said. “We’re trusting it more and we’re using it more.”
Not only did the DRMP team like the fact the mdLiDAR3000 offered a complete solution, they were also impressed with the company. Microdrones is a leader in the drone industry and has proven to be a reliable partner that provides exceptional support.
“Any questions we’ve had they’ve answered. If there’s a software update that would help with productivity, they’re good about contacting us and letting us know and also helping when needed,” Thick said. “The longevity of the company was a big selling point for us. And the system was already set up with the Riegl miniVUX sensors we use, and those are top of the line when it comes to LiDAR sensors.”
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