HIGH-FLYING TECH

Whether he’s conducting missions at the Lubrecht Experimental Forest in Greenough, the Bear Paw Mountains on the Hi-Line, the Moulton Reservoir Ski Trails, or the mountainous areas of the Sheep Creek district in southern Ravalli County, when Geophysics Professor Dr. Xiaobing Zhou uses any of his drone systems, folks nearby often stop and take notice. It would be hard not to. His drones and drone-borne equipment are large, and carry what Zhou says is some of the best aero-geophysical and remote sensing equipment in Montana, used in his geophysical research focused on both hydrological impacts after wildfire, and identifying areas where rare earth minerals occur in Montana.

“Quite a few people are interested in what we are doing with our remote sensing research,” Zhou said, as he gave a demonstration with the GEM AirGRAD magnetic gradiometer. “This is a big, important instrument for us. It’s used to detect magnetic minerals. Some minerals that contain rare earth elements have magnetic signatures we can detect when flying the drone with the magnetic system.”

Rare earth elements are critical components of smart phones, flat screen televisions, computers, newer light bulbs, hybrid and electric car batteries, and pieces of laser- and precision-guided missile technology essential to U.S. defense agencies. For the past two years Montana Tech’s research facilities have been conducting more than a dozen projects funded by the DEVCOM Army Research Laboratory (ARL), focused on exploring, extracting, and processing critical minerals and rare earth elements.

Zhou’s research is one of those projects. “These minerals are very important,” Zhou said.

His magnetic gradiometer setup is comprised of a custom drone measuring a couple of feet tall, with a 10-feet-long tow cable to carry a payload of an approximately 8.5-kg, 12-feet-long fiber glass tube that has an oblong head at one end with electronics inside, with two sensors set up at the other end, 5 feet apart. When it lifts off, it
looks like the drone is towing a giant orange and white arrow in the sky. The instrument is so long it takes two tripods to hold it when it’s not flying. The magnetic gradiometer holds a pair of high-precisionsensitivity potassium UAV magnetometers, a laser altimeter to record the drone’s height above ground, and a GPS for location tracking. An inertial navigation system is constantly tracking yaw, pitch, and roll. All of the data collected are transferred in real-time to the computer on the ground, where Starlink internet provides real-time surface topography data so that the drone can fly at almost constant altitude in remote areas. The drone battery lasts about 10 minutes, so to fly for a long time in remote areas, Zhou carries a set of 10 batteries and four gasoline-powered generators.

“We are limited in flight time by the battery right now, but as technology has advanced, sensors have become much smaller. It has expanded what we can do with our drones,” Zhou said.

Zhou demonstrated by showing a small, 3-D printed gadget thatholds several circuit boards, a radar system a student built. In contrast, the world’s first radar system, constructed in 1935, included four steel towers 360 feet tall set in a line about 180 feet apart. The student’s version of radar fits in the palm of a human hand. Integrating the technology prior to takeoff was a challenge. In addition to using the magnetic gradiometer to seek out minerals containing rare earths, Zhou also has drones equipped with instruments that collect hyperspectral and light detection and ranging (LiDAR) data. Whereas most drones on the hobbyist market are fully integrated together, Zhou’s drones are made up of systems made by different companies in different countries that take a bit of expertise to piece together so they operate in sync.

However Zhou is two years into the ARL project, and at this point using the systems has gotten much easier. Zhou first earned his drone pilot license in 2017. Even though he’s an experienced pilot, flying his research drones is still a bit nerve-wracking at times.

“We want to prevent crashes,” Zhou said. “This drone, along with the hyperspectral and LiDAR system, costs more than $300,000. It is a bit stressful to fly it because of its high cost.”

Zhou usually flies the drone, taking care to maintain a constant altitude from the ground despite any topography changes, while his students monitor data and assist in other ways.

In September, second-year Earth Science and Engineering student Umer Masood, of Pakistan, had the opportunity to go with Zhou to the Sheep Creek area of the Bitterroot National Forest, which has been identified as an area that could contain significant rare earth element deposits. The trip required camping at the beautiful Alta campground.

“I enjoyed it,” Masood said. “We do cool stuff. We go fly drones in the woods. We get to camp when we are working. That’s one of the best parts for me. I come from a really huge town of 2 million people where there’s not a lot of outdoor stuff to do.”

While much of Zhou’s focus is on minerals containing rare earths elements, he also uses his drones to gather data useful in forest management, particularly in measuring the impact of wildfires on the snowpacks in the forest. When trees burn it reduces cover for winter snowpack, which may in turn cause snow cover changes for the watershed. Zhou’s sensors have the ability to estimate biomass, snow coverage, moisture content, and more.

Students have also shown interest in using drones for projects involving search and rescue functions. Zhou says he’s focused on using the larger, more expensive drones for his research, just because it would be difficult to replace the expensive equipment in the event of a crash. There are a number of smaller, less expensive
drones that students train on at Montana Tech. There are more than a half dozen different types of small drones with varying functions and payloads, including fixed wing systems that resemble small model airplanes. One consists of a small, remote-controlled boat that has seven sensors on its underside that can monitor a bevy of water-quality datapoints. In addition to operating drones, students can learn to develop sensors.

“We’ve built sensors to measure air quality and other things over the
years,” Zhou said.

Montana Tech has two drone certificate programs and a number of classes available to students that focus on drone skills. The Unmanned Aerial Systems Development and Analytics graduate certificate and the Unmanned Aerial Systems Applications and Design undergraduate certificate are designed to vastly increase students’ skills and knowledge while minimizing the number of additional credits needed to earn the credentials.

Montana Tech is also part of the Montana Space Grant Consortium, which works to strengthen education in Montana in NASA-related fields, including remote sensing.

Zhou said the equipment, expertise, and programs housed at Montana Tech for remote sensing and drone work hold tremendous potential for students, researchers, and the community.

“We can really do a lot of wonderful work with this equipment that we have,” Zhou said. “Regionally there are great possibilities for airborne work.”