Skip to main content

Naval Research Laboratory is teaching drones to use thermals to soar like birds

Everyone reading this has likely seen birds soaring at some point or other, effortlessly moving through the air without flapping their wings. Unlike regular gliding, which gradually results in a bird losing altitude, soaring represents a special type of gliding in which birds fly on rising air currents, known as thermals.

Dr. Dan Edwards of the U.S. Naval Research Laboratory is also familiar with this type of energy-efficient locomotion. He has been fascinated by it since he was in college.

Recommended Videos

“I was studying autopilots and was hanging out with some of my friends from the robotics club,” Edwards told Digital Trends. “I can’t remember who said it, but someone raised the question of whether it would be possible to catch thermals using an autopilot. That got me thinking.”

Please enable Javascript to view this content

Jump forward in time, Edwards and a team of researchers are the brains behind some smart software called ALOFT, short for Autonomous Locator of Thermals. Its goal is to allow unmanned sailplanes to fly for longer than previously thought possible by using algorithms to locate thermals to surf.

“What they’re doing is finding updrafts to keep these autopilots aloft,” Edwards said. “It’s solving the question of how you program an autopilot to be able to emulate a soaring bird’s behavior to increase the endurance of unmanned vehicles.”

The ALOFT system uses sensors already built into aircraft for measuring information related to airspeed, altitude, GPS and other data. It then logs data whenever it senses the plane getting a lift from rising air currents and based on what is called a “nonlinear curve fit,” figures out the GPS points for where it thinks thermals are located. The autopilot then attempts to hitch a ride on these thermals.

“For autonomous soaring, the goal is to be able to fly for longer while using the same amount of battery or fuel — or to be able to redirect that power to do something else instead,” Edwards said.

While early flights using the ALOFT software proved a success, what is even more exciting is the current direction of the project, which aims to get multiple unmanned aerial vehicles sharing information with one another.

“We’ve created cooperative soaring, during which a number of aircraft all do their own localized sensing and then share their data with the others,” Edwards said. “Just like a flock of birds, each bird is independent, but they will also look at their neighbors to find the best thermals for soaring.”

Going forward, Edwards told us he hoped ALOFT may be incorporated into a growing number of autopilot systems. “What we’re doing at the Naval Research Lab is carrying out research that can then transition out to the wider world,” he said. “I think it would be really interesting to get this technology out to industry for both civilian and military uses.”

Given the continued concern about drone battery life, we cannot help but think his research will be gratefully received.

Luke Dormehl
Former Digital Trends Contributor
I'm a UK-based tech writer covering Cool Tech at Digital Trends. I've also written for Fast Company, Wired, the Guardian…
Hyundai Ioniq 5 sets world record for greatest altitude change
hyundai ioniq 5 world record altitude change mk02 detail kv

When the Guinness World Records (GWR) book was launched in 1955, the idea was to compile facts and figures that could finally settle often endless arguments in the U.K.’s many pubs.

It quickly evolved into a yearly compilation of world records, big and small, including last year's largest grilled cheese sandwich in the world.

Read more
Global EV sales expected to rise 30% in 2025, S&P Global says
ev sales up 30 percent 2025 byd sealion 7 1stbanner l

While trade wars, tariffs, and wavering subsidies are very much in the cards for the auto industry in 2025, global sales of electric vehicles (EVs) are still expected to rise substantially next year, according to S&P Global Mobility.

"2025 is shaping up to be ultra-challenging for the auto industry, as key regional demand factors limit demand potential and the new U.S. administration adds fresh uncertainty from day one," says Colin Couchman, executive director of global light vehicle forecasting for S&P Global Mobility.

Read more
Faraday Future could unveil lowest-priced EV yet at CES 2025
Faraday Future FF 91

Given existing tariffs and what’s in store from the Trump administration, you’d be forgiven for thinking the global race toward lower electric vehicle (EV) prices will not reach U.S. shores in 2025.

After all, Chinese manufacturers, who sell the least expensive EVs globally, have shelved plans to enter the U.S. market after 100% tariffs were imposed on China-made EVs in September.

Read more