FLYING THE RUNWAY

AERIUM Analytics recently completed flights at two Canadian airports using the Microdrones mdLiDAR1000 system. by Renee Knight, Senior Editor

AERIUM Analytics, a Canada-based unmanned aircra systems service provider, is focusing on an area that most other providers aren’t: its team recently used the mdLiDAR1000 system for projects at two airports in Canada.

AERIUM first began flying at airports in 2017, focusing on wildlife management and data collection. While the team uses other systems for the wildlife aspect, the mdLiDAR1000 has proven to be valuable in collecting high quality data sets to be used for engineering and design by AERIUM’s airport clients.

AERIUM purchased the mdLiDAR1000 in early 2018 to offer clients a more complete data collection solution that goes beyond basic videos and photogrammetry. And because of the focus on serving airport clients, the team knew whatever LiDAR-equipped system they chose would be operated in controlled airspace. After doing research, AERIUM found that Microdrones offered a robust, reliable and highly accurate solution, and was one of the few drones compliant with Transport Canada regulations for flight in controlled airspace.

“We have flown runways in the past using photogrammetry and we discovered that due to the nature of runway surfaces, photogrammetry requires specific conditions in order to be as effective as LiDAR for data analysis,” said Brandon Southgate, remote sensing and geomatics specialist for AERIUM Analytics. “It’s hard to resolve and build a point cloud using paint lines and bare concrete. Instead of an indirect measurement, LiDAR is a direct measurement, so we’re able to get a much more accurate height of the runway surface with LiDAR than with photogrammetry.”

“Time saved is definitely a big aspect of it. But the data quality or point density is probably the biggest benefit.”
Brandon Southgate
remote sensing and geomatics specialist, AERIUM Analytics

The Projects

AERIUM completed a project at the Edmonton International Airport in Alberta last October. The team deployed 10 flights in one day, covering two runways, Southgate said. The client is using the data collected to build engineerbased data sets on how the runways look structurally, helping to determine if any repairs are needed. They’d also like to look at taxiways and aprons, which is a project Southgate expects to complete in the near future. That information will be used to help with design engineering and water management.

During the October project, the runways only needed to be shut down for a brief period, Southgate said. While AERIUM flew the system over one runway, air traffic was directed to the other runway so that both could be flown without a huge impact to the airport. This required a lot of communication with the air traffic control tower, Nav Canada and the airport.

The client is now going through the data collected, and so far is happy with the project. Edmonton International is one of the few airports actually using drones, and the team there has been very excited about the projects AERIUM has completed. They’ve been working with the service provider for nearly three years, starting with a focus on wildlife management and then moving on to including the LiDAR flights with the Microdrones integrated system.

Last summer, AERIUM f lew a five-day project with the mdLiDAR1000 at the Erik Nielsen Whitehorse International Airport in Yukon. Like in Edmonton, the team collected data for engineering purposes and water management. The drone completed about 25 flights, covering the entire airport.

Originally, AERIUM was brought on to help determine which of the trees located at the end of one of the runways were problematic. The system was able to collect the data needed to identify which trees should be cut down and which were in the correct range limit.

Most other airports are completing these types of projects by manually surveying with a total station or GPS receiver on a pole, or by using manned aircraft, Southgate said. When manned aircraft come in, it requires much bigger, more expensive equipment, and the process is significantly slower. So, in the case of the project completed in Edmonton, runways would have been shut down much longer, resulting in a bigger impact on the airport.

“Time saved is definitely a big aspect of it,” Southgate said. “But the data quality or point density is probably the biggest benefit.”

Another benefit of using the Microdrones system is the ability to collect data more frequently for better tracking. Typically, projects like the one completed in Edmonton only happen once a year because of the time required and the expense. Using drones, data can be collected as often as the airport wants to collect it.

Challenges

When deploying drones at an airport, the biggest challenge is of course regulatory, Southgate said. That’s why having a compliant, reliable system like the mdLiDAR1000 was so key.

“Just getting access to the airspace for the time required, that’s the toughest,” Southgate said. “Because the engineering groups and the GIS teams definitely want the data.”

Another challenge is the perception people have when it comes to drones flying in and around airports. Many people don’t understand drones can be used in positive, controlled ways in this space. Projects like these can build community confidence.



Data collected with mdLiDAR1000 is used by airport clients for future engineering and design planning.

THE mdLiDAR1000:

  • Is a fully integrated system that produces 3D point clouds optimized for a variety of other applications, including land surveying, construction, oil and gas, and mining.
  • Consistently provides an accuracy of 6 cm (0.2 ft) when flown at 40 m (130 ft) at a speed of 3 m/s (6.7 mph).
  • Is an end-to-end LiDAR solution that combines a drone, a LiDAR payload, a fully integrated software workflow and top-notch support.

Why Microdrones

Not only does Microdrones offer a compliant system that can be flown in restricted airspace, the robust, complete solution makes it possible for Southgate and his team to collect highly accurate data for airport clients.

“We needed the system to be reliable,” Southgate said. “We’re usually able to collect the data we need and keep going. When we do have issues, Microdrones has been pretty responsive. They’re always just a phone call away.”

A BETTER VIEW WITH LIDAR

The team at Spatial Data Consultants is flying the Microdrones mdLiDAR3000 to gather even more details for their clients. by Renee Knight

About a year ago, the team at Spatial Data Consultants decided to invest in drone technology. They knew they wanted a professional grade UAS that could deploy LiDAR, make them more efficient and provide richer data. To get started, they invested in the mdMapper1000 photogrammetry package from Microdrones, and then worked with the company to develop the LiDAR payload that is now on the mdLiDAR3000.

The High Point, North Carolina based geospatial consulting firm was the first to take delivery of the mdLiDAR3000, Director of UAS Services Robert Chrismon said, and began working with the system last August.

“Our focus was to get the LiDAR application. We bought the smaller drone to get familiar with the platform,” Chrismon said. “It gave us a system to train our pilots on as well as an opportunity to use a drone when LiDAR wasn’t necessary. But our main focus was to get into LiDAR, which is why we went with Microdrones and the integrated LiDAR payload.”

At first, the team used the system for volumetric calculations in landfills, but soon realized other applications were an even better fit, such as design surveys, Chrismon said. With LiDAR, they’re able to penetrate through vegetation, which is one of the biggest benefits the technology offers land surveyors.

“You get multiple returns with a LiDAR system that helps penetrate vegetation and get down to bare earth,” he said.

“You can’t do that with photogrammetry. The drone can cover more ground than a conventional survey and get richer data. So a big part of this is the time savings and the richness of the data we get afterwards.”

The Applications

The team deploys the system at least weekly, Chrismon said, whether they have a specific project or are experimenting with new uses. They’re mostly doing topographic and planimetric mapping. The system is flying over rural areas, some wooded some not, that are anywhere from 20 to 200 acres in size.

The team’s most recent project involved a historic graveyard at a local church, Chrismon said, with tombstones dating back to the late 1700s. They used the drone to survey the entire graveyard and generate a database of grave locations. The geo database makes it possible for the owners to keep track of existing lots and build a history, something they struggled with before.

For now, the company has two trained pilots on staff, including Chrismon. As they develop more uses for the technology, they may expand their UAS team, he said. Not only does the company fly their own systems, they also process all their data in-house.

The Benefits Over Other Methods

Chrismon has been working in land surveying since the mid-1990s and said conventional methods he’s used in the past are a lot more time consuming and in a lot of situations not as accurate as aerial LiDAR. Before, workers would walk an area with a ground total station and a prism, taking shots every 25 to 50 feet.

Completing surveys in wooded areas takes a lot of effort, he said, with workers having to physically carve out lines of sight to see through the woods and collect the data. With aerial LiDAR, they’re able to penetrate through tree canopies to get the information they need without having to spend time carving out sections.

“When you do a conventional survey you work on a grid and locate points every 25 to 50 feet. With LiDAR, you’re getting 30 to 80 points in a square meter,” he said. “So instead of having one point every 25 feet, you have one point every few inches. The information you can extract from that data is much richer.”

Although he hasn’t worked out the numbers, Chrismon imagines the increased efficiencies and time savings leads to reduced costs as well.

Future Uses

While LiDAR applications are the firm’s focus, the team is also looking for more ways to use photogrammetry and the md4-1000, Chrismon said. They recently invested in an inspection package from Microdrones.

“We’re looking to grow the inspection side with photos and videos,” he said. “It could be infrastructure inspection, it could be asset management, it could be monitoring environmental issues. We are eager to utilize the +inspection package for our mdMapper1000.”

Why Microdrones

When Chrismon first began looking for a system to invest in, he saw what he described as a lot of low-end toys that didn’t provide what he needed. He wanted a professional grade solution with the ability to integrate different payloads. As he worked with the Microdrones team to develop the LiDAR payload, he was impressed with how the laser scanner, inertial measurement unit (IMU), software and app that controls the interface all integrate together. The integration is smooth, which was important to him.

Chrismon also has been pleased with the level of customer service he’s received from the team at Microdrones, he said.

“We were their first customers using the LiDAR unit so we definitely worked with them more than a typical customer,” Chrismon said. “The service and responsiveness have been great. If we do have an issue, they’re quick to jump on it and give us a solution or feedback. They’re a great group to work with.”

LiDAR: IT’S ALL IN THE DETAILS

ESP Associates, an engineering design and consulting firm, is deploying the Microdrones mdLiDAR3000 to capture more detailed, accurate images for their clients. by Renee Knight

When Brian Flaherty and his team at ESP Associates, an engineering design and consulting firm, started flying drones for clients in 2015, they didn’t see the benefits they had hoped for. While the unmanned aircraft systems (UAS) did help save time on certain projects, the traditional photogrammetry they offered just didn’t provide the accuracy the surveying industry requires.

That’s why they decided to invest in the Microdrones md4-3000 with LiDAR last September. LiDAR gives them the accuracy they were missing, making it possible to penetrate through canopies to see the ground below in a lot more detail than with traditional imagery. They’ve completed about 30 successful flights since delivery, and Flaherty has been pretty happy with the results from the DL system, which uses the Riegl MiniVUX-1DL.

“LiDAR provides better accuracy than photogrammetry, especially under canopy. With photogrammetry, you’re limited to how good a surface model is going to be. If there’s a canopy you really can’t model the surface. LiDAR penetrates through the canopy and collects a lot more information,” said Flaherty, a licensed surveyor who oversees the UAV department for the North Carolina based company. “In North Carolina, we have a lot of canopy, and most of our projects fall in wooded areas. This system from Microdrones just seemed like the best tool for us.”

Detailed surface from LiDAR collection.

How They’re Using the Technology

The team is mostly using the drone for land development, Flaherty said. Clients basically want to know if land they’re interested in is feasible for a project, so ESP collects aerial imagery that allows the engineering group to complete a preliminary design, and then a final design if the client decides to move forward with the project.

Not only can they give their clients more detailed information with this system, they also can get it to them much faster than if they used the traditional methods that involve ground crews walking the area with survey equipment. Before, it might take a month to collect the information they need to map a 200 acre site. With the Microdrones system, they can gather the same information in about two days.

“The turn-around time is much quicker and the accuracy is much better,” Flaherty said. “With this system you’re getting 100 points a square meter, where traditionally you’d get one point every 35 feet or so. You get a lot more information to interpret.”

Using this technology, the team also can see their own field mistakes, such as a bad rod height, Flaherty said. If there’s a branch in the way of one of their five foot rods, for example, the crew might extend the rod two feet so they can collect that point. If they forget to enter the change, the data collected will be off. The two foot difference will show up in the LiDARcollected data, enabling them to account for the error.

There’s also software being developed that will make it possible to use point clouds collected via LiDAR to obtain tree sizes and counts, which Flaherty describes “as a very big thing in development” that can be used during tree surveys.

A surface created from ground points with the trees kept in for visual.

The firm is interested in using the Microdrones system to look at canopy encroachments in right-of-ways as well, Flaherty said, and working with departments of transportation to collect information in areas trucks with mobile LiDAR systems can’t get to. They’ve even done a few pilot projects for these types of flights, but they’re not ready for prime time just yet.

Incorporating the System

ESP has three trained pilots who fly the Microdrones system for clients, Flaherty said. The pilots fly at sites all over the country to support all of their offices. Flaherty also has a Part 107 license.

After the flights, the team handles downloading and processing the information gathered, Flaherty said. It takes about a day to process a day’s worth of flying. They also still use ground crews to collect some of the data they need, so incorporating that information takes a little bit more finesse and time.

After deciding to implement drones, ESP also had to educate clients about the technology and how it can help them make better business decisions, Flaherty said. Some were a bit apprehensive at first, but now most are on board.

“It’s aerial technology and some of our clients have gotten bitten in the past from doing topos (topographic maps) from imagery,” he said. “Now, we find most of our clients realize the benefits of time savings and accuracy from this type of technology.”

Why Microdrones

While Flaherty knew Microdrones developed rugged, reliable systems (he had used other models in the past) that wasn’t the only reason he opted to invest in the mdLi- DAR3000 last fall. He wanted to purchase a system from a company he could turn to with any questions or problems. He certainly found that with Microdrones.

“They support their product. Whenever there’s an issue they get in there and fix it,” he said. “With most of the other platforms we’ve dealt with, it was very painful to get support. It was a no-brainer to go with Microdrones mainly because of the support they offer.”

Details, Details

The ESP team recently flew a wooded area to provide a client with a topographic map. The client needed the map to determine if there was enough volume in their stock piles to fill in the basins there. The area was very dense with a lot of power lines, but because they used LiDAR, they were able to give this client exactly what was asked for.

This is just one example of a successful use case, all made possible by having the ability to deploy LiDAR on a UAS.

“We flew that 40 acre field in about three hours. It would have been a week’s worth of work for a field crew,” Flaherty said. “If you take out the trees, you can see the ground very well. You can see a lot of detail. It’s pretty impressive. You would never get that type of detail with photogrammetry.”

MAPPING CONSTRUCTION SITES FOR BETTER OUTCOMES

Before Ashley Thomas Pittman and the team at Brent Scarbrough & Co. Inc., a Georgia-based heavy steel construction company, clears a site for a project, they need to know its contours and how much dirt must be brought in or taken out to achieve the proper elevations. The engineer-supplied topographic maps are designed to provide that guidance but often aren’t very accurate—leading to extra work that costs time, money and frustration.

That’s why Pittman, who’s with the company’s GPS/ Layout Department, decided to start looking into using an unmanned aircraft system (UAS) to create these maps, and ultimately invested in the mdMapper1000DG from Microdrones about a year ago. Deploying the system is more efficient and safer than traditional surveying methods, and provides the information he needs to efficiently complete his job.

“We were having a big disparity between the existing topo that came with the set of plans and what we were finding on the site. We really found some shocking differences,” Pittman said. “We’d be two-thirds or three-fourths done with a site and realize we didn’t have enough dirt or that we had too much dirt. That should be worked out ahead of time. We can raise the site according to anticipated overages or shortages at no additional cost if we know in advance. When we’re surprised toward the end, we have to remove all the dirt to fit a different type of topo.”

The Benefits of UAS

Brent Scarbrough typically works on large sites that are between 50 and 60 acres, said Matt Rosenbalm, the Microdrones Southern U.S. sales manager. The sites are filled with heavy equipment and often have treacherous terrain. Before the construction company began deploying the mdMapper1000DG, two or three workers would survey the sites with a GPS rover, a time-consuming, often dangerous, task. Now, they can get the data needed to build 3-D modules and perform volume calculations in minutes.

civil_maps_-_3dmappingtech

“A drone flight takes a fraction of the time of almost anything we were doing by hand with conventional GPS instruments,” Pittman said. “I can topo a 10 acre site that might have taken a day to complete in 12 minutes. Twelve minutes versus 10 hours is kind of a no-brainer.”

The company has one drone pilot who handles all the flights, Pittman said. He was trained by SITECH South, the region’s official Microdrones distributor. He can fly as much as needed, usually 2-3 times a week. The pilot then processes the data, which takes about four hours to complete. The drone also now comes equipped with LiDAR, making it possible for the team to access data in less than an hour.

“Because we’re saving time we can topo way more than we ever did,” Pittman said. “And it frees up our crews to do what they need to do rather than working on a topo. That was traditionally part of their jobs, but we’ve been able to separate that out because of the drone technology.”

The high-resolution photographs the UAS collects also can be seamlessly stitched together to create mosaics of every site, Pittman said.

“That really helps when the owners, developers or anyone has a question about something on the topo,” he said. “I have a high resolution photo that shows what type of material is on a site. We can then do a stock pile evaluation and see how much of that material is there.”

Why Microdrones

When the construction company first decided to invest in a drone, the team knew they needed a commercial grade system with endurance, said Paul Shepard, a Sales Engineer for SITECH South. Brent Scarbrough purchases GPS solutions from SITECH South, so it made sense for them to consider Microdrones first. After they learned more about the mdMapper1000DG, it became clear it was exactly what they were looking for.

“They knew they’d f ly the system several times a week, and needed a drone that could handle a heavy workload as well as carry various payloads, including high-res cameras and LiDAR,” Rosenbalm said. “The mdMapper1000DG offers both, and has motors that last up to 10,000 hours with little maintenance. The system’s lower speed also produces less noise, which means it can typically f ly undetected.”

“And because the system uses direct georeferencing, there’s no need for multiple ground control targets,“ Shepard said.

“With a traditional drone, you’re going to put out 10 to 15 ground control targets,” Shepard said. “They would have to put those out uniformly across the site, intermingling with the machines. By using the mdMapper1000DG, they only need a few ground control targets, which speeds things up and keeps them out of harm’s way.

A Learning Curve

After investing in the drone, it took time for the team to incorporate the best workflow, Pittman said. They were bringing in bad data at first, but with guidance from Microdrones and SITECH South, they now have an efficient solution that quickly provides them with accurate topographic maps.

“They worked with us to make sure all the settings on the drones were correct and that we knew what they were,” Pittman said. “Flying the drone is the easiest part. The hardest part is doing the processing and having a guy in place who can replicate a good process over and over. We’re finally at that point.”

Solving a Problem

Developing accurate topographic maps can be expensive, which is why many owners choose to go with less costly, but also less accurate, methods to obtain them, Pittman said. Often, the maps aren’t a true representation of the site, which can cost construction companies a lot of time and money. The drone gives Pittman and his team access to a more accurate topographic map in less time than traditional methods, ensuring they’re properly prepared for the project from the beginning.

“The engineers can get the topo from a variety of places, whether it’s LiDAR, flood mapping or GIS. That makes a big difference, but we never know where they come from,” Pittman said. “It could be really close or it could just be an assumption of what the contours are. When we fly the drone, we get a topo we can compare to what the engineer thinks the site looks like before the dirt starts moving.”

SAFE, RELIABLE FLIGHTS PRODUCING ACCURATE RESULTS

Microdrones has been flying the mdMapper1000DG advanced aerial mapping solution at the White Birch Paper mill in Quebec City for three years, providing a safer, more cost-effective way for the company to measure wood chip piles. by Renee Knight

Every three months, a team from Microdrones flies the mdMapper1000DG over the wood chip piles stored outside the White Birch Paper mill in Quebec City, providing the mill with valuable information about their inventory.

The mill transforms these wood chips into cardboard paper, making it vital for company leaders to know exactly how much volume they have in each pile, Microdrones Canadian Sales Manager Sebastien Long said. Before they started working with Microdrones about three years ago, this was a dangerous, time-consuming task that was performed using traditional surveying methods.

Now, a process that once took a few days to complete only takes a few hours, and there’s no longer a need for workers to walk around the heavy machinery in the area or to climb on top of the wood chip piles—which is a lot like trying to walk on mounds of sand—to collect the necessary data.

“This is safer, faster and we get a better data set,” Long said. “The numbers we get are more accurate than what they used to get from surveying. In the past, they’d take images of the piles and convert that into 3-D. With the drone, they can get better coverage of the surface than someone walking the pile and taking a rating here and there, every 6 or 12 feet. The drone covers 100 percent of the pile and we’re able to give them accurate data of the volume and their inventory.”

Why Microdrones

The mill is located in the middle of a city and near an international airport, so when the team decided to invest in a drone for inventory management, they knew the system they chose had to be safe and reliable—they couldn’t risk it getting away from the pilot, or failing during the middle of a f light.

“They wanted to make sure they were f lying with a company that was serious on every level,” Long said. “When a large company like White Birch is flying something in the air, they have to make sure it’s reliable at all costs. That’s one of the strengths of Microdrones. We have a highly reliable platform.”

After reliability, accuracy was the next top consideration, Long said. The system had to provide at least the same level of accuracy as the manual surveys, a benchmark the Microdrones solution had no trouble reaching and surpassing.

The Advantage of DG

White Birch paper mill started with the original mdMapper solution, but then moved on to the more advanced mdMapper1000DG drone. This system features direct georeferencing (DG), which means there’s no need to lay down multiple ground control points (GCPs) on what is very dangerous terrain, Long said.

“If you use our entry level system or any other sensor or drone on the market, you have to lay down ground control points that help you get the level of accuracy you need. The GCPs help ensure the measurements from the pile are correct and that you can process the data as a volume,” Long said. “When you use DG, you don’t have to do that, which saves a lot of time. You also don’t have to walk around the piles of wood chips to put the GCPs in place, so it’s safer and the results are accurate. You’re still using a base station, but it’s easy to set up. You can also use a smart target. As long as the target is appearing in the images, you’re good to go.”

Using DG also reduces overlap, Long said, leading to faster post processing times after the 200 or so images are taken.

Overcoming Weather Conditions

The mill’s city location wasn’t the only challenge the Microdrones team had to overcome when taking on this project. They also had to contend with weather, Long said.

Quebec City is known for its harsh winters that come with extremely cold temperatures and plenty of snow, which can make flights a little difficult during that time of year, Long said. The mill is also located near the St. Lawrence River, which often brings heavy winds to the area. Pilots have to consider these conditions when it’s time to fly, but they know the robust Microdrones system is built to handle adverse weather.

A Happy Customer

Now that Microdrones handles wood chip pile surveys for White Birch, there’s no need for the mill to send workers out to do the job manually. So instead of surveyors coming away with an incomplete picture of the pile volumes, the Microdrones solution stiches the images together to create a 3-D map of the pile, and data from that 3-D model is then brought into volume calculation software to provide the exact volume of every pile on the ground.


The mdMapper1000DG flies over a wood chip pile at White Birch Paper mill in Quebec City.

“They wanted a solution that was accurate, cheaper and safer for operators on the ground and for the people in the area,” Long said. “We’ve been able to offer that, and have proven over the last three years that we can provide more accurate data than they ever had in the past.”

COURSE CORRECTIONS WITH UAS-BASED LiDAR

Frontier Precision uses fully integrated UAS-based LiDAR system to help contractor meet unusual topographic specifications. by Vicki Speed

A historic golf course in Denver, CO. became the hotspot for a demonstration of next gen integrated UAS mapping technology.

Denver Public Works and Denver Parks & Recreation are facilitating a complete redesign and revitalization of the 200-acre City Park Golf Course to integrate storm and groundwater drainage systems as part of a larger flood mitigation program in the city.

The project’s contract documents outline some sitespecific development requirements to support the stormwater management such as the integration of storm and groundwater drainage systems to temporarily hold and slow floodwater during major storms. Environmental specifications for reforestation require the contractor to carefully monitor earthwork and site development activities.

Working with the general contractor, Frontier Precision, a survey and civil engineering company headquartered in Bismarck, North Dakota with offices in Colorado, used the opportunity to compare the latest in fully integrated UAS-based LiDAR and direct georeferencing with conventional survey mapping techniques.

Flexibility & Speed

To map the 200-acre golf course, Frontier Precision got a first-hand look at Microdrones’ new mdLiDAR1000. Designed for ease-of-use, the mdLiDAR1000 is a fullyintegrated unmanned aerial system equipped with a LiDAR sensor, software and workflow capable of producing high accuracy geospatial solutions very quickly.

Nathan Stephenson, laser scanning engineer in charge of technical scanning services with Frontier Precision, was particularly excited about seeing the mdLiDAR1000 solution for the first time. He added, “We haven’t supported aerial LiDAR platforms to-date because the technology was still being developed and wasn’t yet at a cost-effective rate. But, from a technology perspective, we are moving more to the use of LiDAR with direct georeferencing because of the technology’s flexibility, ease of data collection and improved safety because of limited need for ground base stations.”

Stephenson worked with Yannick Savey, Microdrones LiDAR test pilot, to develop the flight plan. The LiDAR data was collected in four flights, each about 20 minutes in length at 3.5 m/s at an altitude of 40 m. The survey team was able to fully map the 200-acre site in less than 50 minutes with the help of direct georeferencing.

According to Microdrones, direct georeferencing is a highly efficient method for connecting aerial images to their geographic positioning on the Earth’s surface. Key in the process is the integrated GNSS/IMU that measures the true 3D coordinates and orientation angles of the sensors, which allows for direct map production. Direct georeferencing has been shown to surpass the accuracy of others georeferencing methods such as traditional aerial triangulation, RTK, and PPK. RTK and PPK have inherent problems that reduce their accuracy, productivity and efficiency. Many of these problems are revealed upon a detailed analysis of their associated mathematical and scientific principles and calculations. One of the major factors for the reduced accuracy of RTK and PPK is the calculation of orientation angles of any sensor. Direct georeferencing measures the orientation angles of the imaging sensor with high accuracy and high frequency at 200Hz or more (200 times per second)

After completing the f lights and post processing the data, Stephenson was sold. He said, “It took us six hours to f ly, process and produce the topo and contour map. That’s impressive. We really liked the fact that it is a turnkey fully integrated solution where the sensors, particularly the IMU/LiDAR, all talk to each other.”

The Forest of Trees

For the general contractor, one of the biggest advantages of the LiDAR-based solution on the golf course project was the visibility through vegetation. As part of the design, the new course design incorporates a detailed reforestation plan to preserve existing healthy stands of trees and maintain the park-like feel. Ultimately, the course will have a net gain of 500 trees.

As part of the owner specifications, the contractor is not allowed to develop the site within 1.5x the canopy width of trees. As part of the mapping process, Frontier Precision used the LiDAR data to produce a topographic survey and contour map with an emphasis on tree widths.

Stephenson says, “The greatest value for us from this project was how quickly this type of data can be collected. The contractor had performed a similar topographic survey of the site prior to construction, which took approximately two weeks and considerable labor and equipment costs. Now we’ve got some real-world cost metrics that demonstrate the value of a fully integrated UAS-based LiDAR solution.”

Talking about the mdLiDAR solution, Microdrones Savey concluded, “This project effectively demonstrated the efficiency of our system. In less than two hours, we were able make a full map of the site with a LiDAR and it took less than 50 minutes to do so with a direct georeferencing. We believe the combination of efficiency with the great precision of our systems, and the professionalism of the team, is a recipe for success.

MANAGING CONSTRUCTION SITES with MICRODRONES

Strabag, a European-based technology group for construction services, recently invested in Microdrones systems to more safely and efficiently monitor construction projects, perform inspections and complete volume calculations. by Renee Knight

Based in Vienna, Strabag SE, covers all areas of the construction industry and is responsible for complex infrastructure and facility management projects all over the world.

To help monitor and complete these projects more efficiently and cost effectively, Dr. Thomas Gröninger and the team at Strabag AG in Germany decided to invest in unmanned aerial systems (UAS) technology earlier this year. After doing their research, it was clear Microdrones offered the best solutions to meet the company’s needs.

“The most important consideration for us was the camera system,” Dr. Gröninger said. “Microdrones offers large cameras and a very good platform. The integration of Microdrones increased the efficiency of different processes in our company, which is why we invested in this very developed drone.”

Strabag also needed a secure, robust system that offered long flight duration, Dr. Gröninger said, which the Microdrones systems also provide. Over the last several months, the team has deployed the drones to monitor projects, plan construction sites, perform inspections and to compute highway surface volumes. Strabag first invested in the mdMapper1000 for its photogrammetry capabilities, and then the md4-3000 for its ability to carry heavy LiDAR sensors and mapping grade cameras.

So far, not only has Dr. Gröninger been happy with the information his drones have been able to collect and how that information has helped to streamline operations, but also with the level of service Microdrones provides.

Highway measurements

One of the main ways Strabag uses the Microdrones systems involves flying over highways to complete surveys and compute surface volumes, Dr. Gröninger said.

“We fly the drone over a highway and the drone takes many pictures that have overlap. After the drone lands, we put the pictures into photogrammetry software to compute a 3-D point cloud,” he said. “We can then make a model of the area and compute volumes. We can do everything with this data.”

Strabag invested in the md4-3000 drone for its LiDAR capabilities—which are put to use for these surveys. LiDAR makes the once tedious, dangerous highway measurement process even faster, Dr. Gröninger said, because instead of having to compute the 3-D point cloud in the software after the drone lands, the point cloud is available to the team as soon as the UAS finishes gathering the information.

Normally, collecting the measurements necessary to create a 3-D model of a highway would take about a week to complete; with the Microdrones system, the team can gather the information in just one day, Dr. Gröninger said. With the old method, workers would have to walk along the highway as they measured, which can be a dangerous task, especially when traffic is heavy. Flying a drone instead doesn’t disrupt traffic and is safer for both the workers and the travelers.

“Microdrones UAS have a very long flight time and also are fail safe systems,” Dr. Gröninger said. “The quality of their UAS is very high. Because we fly the drone over highways in an area where there are many cars, it’s important to have a high security, high-quality drone so it doesn’t crash into traffic.”

Construction planning and inspection

Strabag also deploys the Microdrones systems to obtain high-resolution, 3-D images of construction sites, Dr. Gröninger said. These images can be used to help with both planning and monitoring different projects. Everyone involved with the project can easily access and refer to the images, and they can fly the site as often as they’d like. A drone typically flies over the sites once a week, Dr. Gröninger said, so construction leaders can adjust plans and schedules as necessary.

“The most important way we use the drones is creating 3-D models. Usually, we only have plans on paper and don’t have 3-D data of the construction site,” Dr. Gröninger said. “It’s all very useful for the construction leaders for both planning the site and observing the progress of the construction. We can see where to reduce costs and where to speed up processes in construction. We also get the data more quickly than if we used traditional methods.”

Strabag also deploys the drones to complete infrastructure inspections, another application that saves them time and money.

“For inspections, you usually need a person to climb, for example, on a big wall or on a tower with a camera to collect pictures for evidence,” Dr. Gröninger said. “Microdrones has a high resolution camera with optical zoom, so we can fly around the building to take the pictures. No one has to climb the building and we get the pictures very fast.”

Moving forward

As a whole, the company deploys a Microdrones system about once every two days, Dr. Gröninger said. They’ve inspected bridges in Columbia, Africa and Austria, and have flown construction sites all over Europe and the world. They plan to continue to fly UAS to streamline operations and reduce costs, and have found a trusted partner in Microdrones, the company that provided them with high-quality, reliable systems to enhance their processes and cut costs.

“Strabag sees big potential in the use of UAS technology,” Dr. Gröninger said. “We have an international project with UAS, and we’re focusing on improving our workflows with this technology. It saves time and reduces costs, and that is very important to us.”

And part of that is because they’re deploying a system that comes equipped with everything they need to be successful, developed by a team that’s constantly learning, evolving and identifying their customers’ needs—and then creating solutions to meet those needs, said Mike Dziok, Marketing Director for Microdrones. As company president Vivien Heriard Dubreuil likes to say, Microdrones doesn’t just sell drones, they sell the whole package.

“It’s the software, it’s the sensors, it’s the drone perfectly integrated with all the human aspects that tie into that,” Dziok said. “Where do I see us in five years? The leader within the geospatial, construction, engineering segments, providing fully integrated surveying solutions. There’s a lot of good technology out there, but I think it’s our people and the world-class teams that we’re building that are going to put Microdrones on top.”

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