PUSHED to the
BORDERLINE
BLM Mosaics America With Cast Aside DOD Equipment
ROAD SHOW
By Danielle Lucey The landscape is changing, and the Bureau of Land Management is watching and waiting. The agency is tasked with mapping the grasslands, forests and creek beds of the country, monitoring their changes and feeding the data to other agencies. But for them, another landscape may soon be shifting — after years of tweaking and rigging Department of Defense unmanned aircraft, the shifting UAS commercial market could soon herald for the bureau an era where its systems aren’t second-hand military spy tools, but are actually made to map. uuu
“For us, it’s not just a pretty map,” says Lance Brady, UAS program lead for the BLM. Brady’s life path led him to unmanned mapping from a blended background of manned aviation and aerial photography. A second-generation BLM employee, Brady spent his childhood growing up near the regions in Arizona he and his mixed BLM-U.S. Geological Survey crew mapped on a mission with Unmanned Systems in mid-November. He now lives in Colorado and is the point person for all of BLM’s unmanned flight activity.
Photos: AUVSI.
These projects are the antithesis of government waste. Brady and the crew use a mix of traditional photogrammetry equipment and UAS that are the agency’s version of the Island of Misfit Toys.
The Department of the Interior, which houses the BLM, has 22 old Honeywell T-Hawk kits, two platforms in each, initially bought by the Army at $750,000 a pop. Originally BLM also received 15 AeroVironment Raven
kits, each containing three aircraft, from the military. Because of wear and tear, it now has two of the kits, which had an original price tag of $250,000 each. Both systems were cast aside by the military, but they came at no cost to the BLM. The Army either was going to give away the systems or be forced to destroy them — and more importantly their GPS data. When the Afghanistan and Iraq conflicts were ramping up, Secretary of Defense Donald Rumsfeld famously said, “You go to war with the army you have, not the army you might want or wish to have at a later time.” For that era’s army, drones were the shiny, flashy new tool when it was in desperate and immediate need of good surveillance data. And these T-Hawks now used by BLM clearly were The Drones You Have for the Department of Defense. For one, they are ruthlessly loud. The gas engine destroyed any hope of mission secrecy for the Army. It also forced troops to lug special fuel around instead of the standard grade typically used by the military. “They realized it didn’t really meet their mission,” says Brady. Shaped like a small trash can and reminiscent in din of a lawnmower, now those UAS are The Drones You Have for the BLM. Bestowed on the agency three years ago, they do have an impressive hour-long flight capability, higher than many vertical takeoffs on the market today nearly a decade later. But the engine proves a little too much for the ductedfan system’s body, creating a good amount of vibration that adds a layer of difficulty to good imagery capture. Brady longs for a platform that was
made expressly for mapping. Free aircraft aside, these missions have a low price tag in other ways. The BLM and USGS crew, both based near Denver, prefer to drive to their missions if they can, even if they are eight hours away. Though it hasn’t happened yet, the flight crew has contemplated camping instead of staying in government-rate hotels, since often their field work is more than three hours from the nearest town. And there are no elaborate lunches for Brady and crew. Most days consist of instant soup heated up in an electric Thermos, packed sandwiches, kids’ squeezable applesauce and trail mix. November’s mission brought the team to the Las Cienegas National Conservation Area, just outside of Tucson, to image an eroding grassland area and an area of trees. They also headed south to Douglas, Arizona, to look at a creek bed that alternates between dry and inundated in the monsoon season. Safety is key to all the agencies’ operations. Each day begins with a briefing, and each witness to the operations has to sign a flight log. “It’s all about mission planning, and after that it’s all about check lists and paying attention,” says USGS Mission Lead John Vogel. There are a few basic ground rules on the four-day mission. No flying if the winds go above 15 mph. Always be on the lookout for manned aircraft that might have missed their notices to airmen. Do not be closer than a few hundred feet to the aircraft upon takeoff and landing. This mission has an atypical request — be on the lookout for any border crossings. JANUARY 2015 | UNMANNED SYSTEMS
| 37
The Douglas creek bed is spitting distance away from Agua Prieta, Mexico. The area the BLM and USGS had to map was so close to the fence that Vogel had to stand next to it to make sure the T-Hawk didn’t accidentally fly out of U.S. territory. Reapers from nearby Fort Huachuca patrol those skies in earnest every day. But the little T-Hawks proved so loud that a BLM border security patrolman tasked with the crew’s safety reported, after radioing with U.S. Customs and Border Protection, that border-crossing activity was down that day, likely because of all the racket. The BLM doesn’t need a certificate of authorization from the Federal Aviation Administration to fly. It operates under a memorandum of understanding, so each night before a mission Brady clears the next day’s activities with the agency. “We inundated them with COAs, and they’re in remote areas like this,” says Brady. “In terms of safety, what’s the safety issue out here with air traffic?” After proving their track record, the FAA agreed upon the memorandum. They opted for the T-Hawk instead of the Raven for these flights because of its higher payload capacity. “Raven can cover more ground, and it’s better suited to windy conditions, but it doesn’t have the payload ability, so it’s a tradeoff,” he says. And not all the BLM’s missions are done with UAS. When a bureau field office poses a task to Brady, he assesses if unmanned aircraft are the right tool at all. For instance,
Brady retrieves the T-Hawk after a flight imaging grassland in Arizona.
The BLM and USGS have collaborated on missions for years after receiving UAS flight training together.
if they want him to image 5,000 to 10,000 acres, Brady will tell them to either focus on a smaller area or do a traditional mission. “Right now I don’t see these taking away from any of our manned aircraft programs,” Brady says. But that is not the case this week. “We could never do this mission with a manned aircraft,” he says, calling it too low and too risky. Brady recalls one mission for the U.S. Department of Agriculture’s Agricultural Research Service where they were flying ultralight manned aircraft at 500 feet. “That’s a huge safety red flag for me.” These photogrammetry and mosaicking tasks have their roots in a much older profession than aviation. Missions called for ground surveying, where a person on foot would shoot around 500 or 600 photographs, ensuring there was enough overlap to create a mosaic in post-processing. UAS are a “tremendous time saver” versus that method, says Brady, which they sometimes still use. Still the crew needs to do some legwork before they can send the UAS up in the air. Prior to all their Arizona flights, they used handheld GPS units to place ground control targets, about one square foot in size and painted black and orange in a four-checker pattern. “Without the targets, we can use GPS embedding in the imagery, but now we’re talking in yards instead of inches,” says Vogel, in terms of the accuracy. The flights — 15 in total for the week at about a half-hour each —
Brady getting the T-Hawk out of the case and assembled.
Dustin, left, and Vogel, right, discuss a flight mission.
represent a small portion of the work the crew does. “This part is the easy part, the flying,” says Brady. During each flight, the team places a new camera on the T-Hawk, sometimes favoring a Pentax Ricoh GR, which has a faster shutter speed, and sometimes using a Cannon SX260, which has the added bonus of embedded GPS data. All the data get overlapped into a mosaic that their software displays as a series of dots. Flying this way, they can get between two to three centimeters’ accuracy. They are flying low on these missions — between 200 and 250 feet — because that provides the best detail in their images. “There’s that trade-off of height and detail,” says Vogel. On a typical flight, the T-Hawk will fly in transects — mowing the lawn in one direction and then flying perpendicular to those lines. It captures around 500 to 600 images per sortie. Flying this way, they can determine the topography of an area by measuring the angles around an object, according to Mark Bauer, a geographer at USGS. Staggering flight elevations also refines this process, and they can combine different resolutions. “If you have too much scale difference, it will break,” he explains. You can’t do a 1,200-foot flight and then one at 400 feet. Bauer says it doesn’t matter what the lighting conditions are outside when they capture, but you want different tools for different scenarios. “If you are forced to use a smaller sensor, then the answer to that is a sunny nice day, but in terms of collecting a more clean picture,” then clouds would be better, he says. “That would be better, but you need a larger sensor size.” The team can process a lot of 40 |
UNMANNED SYSTEMS | JANUARY 2015
the data on site, using the software Agisoft PhotoScan, which leverages a technique with its roots in range imaging called structure from motion. The software looks for correlations among the hundreds of images and creates a three-dimensional point cloud. Google Earth or a geographic information system layer could find common points too, but “it’s a lot more challenging,” says Brady. However, “we’re kind of software agnostic,” he says, since structure from motion is common. He selected PhotoScan because it has the most efficient workflow. It can find 40,000 points in common in one photo to make the mosaic. Each data point has an x, y and z value, but the software assigns positions and an RGB value based on the imagery. It also sorts out color discrepancies. For instance, the Ricoh is modified to capture in the near infrared, which means in post-processing it displays some unnatural colors. The data take a couple of hours to process. “Imagine if you were in a virtual reality world. … That’s somewhat what the surface would look like,” says Brady. All the data are stored at BLM’s National Operations Station in Colorado, but in the future Brady hopes to distribute it online. Some of it is sensitive, like for cultural resources programs that might attract
the wrong attention, so it would be carefully selected. Brady says people could use the Freedom of Information Act to obtain his data, but there’s an easier alternative — just ask. “We’ll hand out data if we have time,” he says. uuu
Gita Bodner is one of those people that would like more data. An ecologist with The Nature Conservancy, she’s spent nine years focusing her efforts on restoring the grassland the BLM and USGS imaged on day one of their mission. The area has been aerially imaged since 1930, but today is the first day Bodner has ever seen it done with an unmanned aircraft. “None of [the older imagery] is anywhere near this high resolution, where you can tell what plants are what and you can tell easily the difference between the giant perennial grasses that are the foundation of that ecosystem and the low-growing annuals that will come and go,” she says. The grass in this area, called sacaton, is hardy. It stands as tall as a person and it can live as long as 100 years. It grows in floodplains like the one in Las Cienegas, but the water table there has dropped. When these grasses die, the soil under them becomes very fine and easily gets washed away in the summer and winter runoff from the Santa Rita Mountains. It is also victim to wind erosion, which
was particularly pronounced this past spring, explains Bodner. “We just want to make sure that if there’s any injuries to those places that we get those healed up as fast as possible, because when they’re healthy, they can handle the biggest storm you can throw at them,” she says. “When they’re not healthy, they will basically unravel.” And though the technology to image these areas is particularly sophisticated on this mission, Bodner says the way to fix the problem is very low-tech. Strategically placing rocks around the soil is an easy way to prevent further erosion. This past summer, local high school students did this through a program called Youth Engaged Stewardship that chose the sacaton grasslands as a restoration project. “They’re going to be so excited to use this imagery, because it will show them how effective their work was this last summer, and it will show them areas that they might want to choose for next school year project and next summer projects.”
Ideally, she’d like the area imaged every summer, so she could see which plants still are green and have access to water. “The ability to get the images when you want them is going to be great. I’m already excited into talking them into coming back.” uuu
The partnership between BLM and USGS was grown from proximity. The agencies’ Colorado offices are down the street from one another. The DOI is also sparse on pilots — the BLM has four and USGS has about five that are certified on unmanned aircraft. “We have to work collaboratively, because there are not many pilots and there are only so many systems to go around,” says Brady. They all got their training together, initially in a two-week course on the Raven and then with a follow-up one-week class on T-Hawk. This particular mission did not require a pilot’s license for the opera-
tors, though other missions do. The T-Hawk takes off and lands through remote control, but the transects are flown autonomously. Brady estimates they have flown around 20 to 25 individual projects on the T-Hawk and have racked up about 350 to 400 flight hours between USGS and the BLM. “We have to turn away work,” says Brady. “We’ve got a lot of stuff going on.” Still, Brady has been looking for ways to make things better instead of just making do. Camera technology is changing faster than UAS technology can keep up with, he says. And the stabilization on T-Hawk isn’t where he needs it to be. “We find issues with aerial photography and satellite stuff, … but we’ve had problems with our imagery as well,” he says. “Our aircraft is shaking like crazy.” He hopes to have new aircraft within a year’s time. “We want aircraft that are specifically designed for mapping. … We need some flexibility,” he says. JANUARY 2015 | UNMANNED SYSTEMS
®
| 41
MicroPilot is the choice of over 850 clients in 70 countries
World Leader in Professional UAS Autopilots
Board Autopilots
Triple Redundant Autopilots
Horizon Ground Control Station
HORIZONmp
• No fly zones, safe altitude and radio range • Integrated simulator provides
trueHWIL
Enclosed Autopilots
Xtender validate
training mode • Multi UAV and Multi GCS Support • Point and Click Waypoint editor histor • See video footprint, history, and cursor
1 (204) 344-5558 | info@micropilot.com | www.micropilot.com
UAS Autopilots | GCS Sooware | Integraaon Tools