'GOOGLE EARTH ON STEROIDS'
High-tech drone gives UF researchers a bird's-eye view of nests off Cedar Key
Published: Wednesday, May 7, 2014 at 6:01 a.m.
Last Modified: Wednesday, May 7, 2014 at 2:51 p.m.
CEDAR KEY — About 300 feet above Seahorse Key, the 9-foot-long wings of an unmanned aircraft wink in and out of view as the drone flies back and forth over the brown pelicans, white ibises, great blue herons and other birds nesting in the black mangroves on the northwest point of the island.
Its electric motor buzzes in and out of earshot, occasionally blending with the chittering of the roosting birds, which are undisturbed by the passes the drone makes as researchers with the Florida Cooperative Fish and Wildlife Research Unit monitor it via computer on a skiff rocking in the gentle chop of the Gulf of Mexico.
Equipped with a high-resolution digital camera, the 14-pound aircraft designed and built by University of Florida mechanical and aerospace engineering graduate students is photographing the nests with pinpoint accuracy for wildlife officials to study.
They are testing the drone — which they prefer to call an unmanned aircraft system — to see how accurately it can locate those nests. But they also are testing to see if the birds are disturbed by the plane's constant passing movement.
A camera on a pole near the shore records the birds' reactions, if any.
“We don't see any reaction from the birds, which is nice,” said Peter Frederick, research professor with the Department of Wildlife Ecology and Conservation at UF and a member of the research team — a joint effort between UF and several state and federal agencies.
The aircraft is the latest in the evolution of unmanned aircraft systems research at UF and represents the latest technology available, he said.
“The first thing we flew was a radio-controlled plane that we glued a video camera onto,” Frederick said. “This is much more advanced.”
And please don't call it a drone, he said. “Drone sounds military,” Frederick said. “It has a negative connotation of killing, of some unthinking thing.”
Also, it implies a thoughtless instrument flying through the air without human control, he said.
“It really is a system, with its photo equipment, georeferencing data, linked to a computer on the ground,” he said. “It is very integrated with humans on ground at all times.”
Unlike the radio-controlled airplanes flown by hobbyists on the weekend, flying Nova 2.1 is no simple matter. The FAA must inspect the aircraft and issue a Certificate of Airworthiness before it can fly. The FAA also requires a special permit to fly the plane and requires that a licensed pilot operate the controls and maintain the same open radio frequency as the Cedar Key airport to communicate with any pilots flying other aircraft in the area.
UF also must file each day's flight plan with the airport, called a Notice to Airmen, which lets other pilots know how high the UF plane is going to be.
The drone flies autonomously along a computer-programmed flight path, cutting a tight, precise swath of overlapping rows — much like a lawn mower pattern, which is why they call it “lawn mower mode” when the aircraft is doing its thing, Frederick said.
The drone's payload includes an on-board GPS unit that provides real-time location and a military-grade inertial measurement unit that monitors the craft's altitude and speed that also can adjust for pitch, roll and yaw so that it stays on target even when the crosswinds are blowing. Matt Burgess, a graduate student and coordinator of the Unmanned Aircraft Systems Research Program, sits under a black shroud monitoring the drone via a computer while pilot Joe DiRodio mans the hand-held controls.
If an emergency arises, DiRodio can switch over to manual mode and bring the plane in for a soft landing on the water — as he had to do once on this particular Monday morning.
The aircraft developed an aileron problem at takeoff, and the crew thought it had taken on water. DiRodio was able to put it on manual and bring it down so they could check it over, make the repairs needed and send it back into the air.
The bottom of the fuselage is designed like the hull of a Boston Whaler, and its propeller flexes backward so it doesn't break or cause the plane to pitch nose first into the water.
A conventional airplane or helicopter also can't get within 300 feet of hundreds of nesting birds without frightening them off in a mighty explosion of flight. Frederick could fly over the rookery in an airplane, at about 1,000 feet, but then he wouldn't get as accurate images as the drone can provide, either.
“I can fly a Cessna over this and take pictures. Anyone can do that,” Frederick said. “This can fly at a lower altitude and get the precise location of the pictures with its onboard GPS.”
That accuracy is crucial to getting a good relationship between the hundreds of pictures taken so they can be stitched together into one giant aerial photo of the nesting grounds.
The objective is to measure nest turnover — to document total number of nests during a nesting season. On Seahorse Key, the nesting season lasts from March through June, Frederick said.
The birds nesting one week could be completely different from the birds nesting another week, he said. By coming out each week to photograph the nests, he and his team will record a history of each dot or nest for the season — and use computer modeling to figure out the super-population, or all of the birds that nested here this year.
Most of Frederick's work is in the Florida Everglades, where the application of this technology can help produce far more accurate estimates of nesting birds, where colonies can range for miles. (One limitation is that the FAA won't allow the drone within a 30-mile radius of Miami International Airport, which covers a large part of the Everglades, Frederick said.)
Knowing how many birds are nesting helps scientists manage the natural resources. They can tell how the birds are thriving, which in turn tells them how the habitat is doing. A shift in the brown pelican population, for example, could mean a collapse of the fisheries, as has been observed in the Indian River Lagoon.
The Nova 2.1 has been this team's workhorse for four years now, and represents the fourth or fifth evolution of this unmanned craft, said Peter Ifju, a professor of mechanical and aerospace engineering at UF. Graduate student Tyler Ward built the camera system, and fellow graduate student Abraham Balmori built the plane.
The craft is equipped with an electric motor powered by an 11-amp lithium battery that consumes about 200 watts of power during a steady cruise with a cruising speed between 35 and 45 mph, and eats up thousands of watts on takeoff, Ifju said.
It has a flight time of a little over an hour. It takes 20 images a minute — or about 1,000 photos during a 50-minute sweep over Seahorse Key. It can photograph two-thirds of a square mile in two 50-minute passes.
After nearly an hour in the air, the drone completed its first sweep. DiRodio landed it on the water, and the crew retrieved it. They picked it out of the water and took the wings off to access the payload inside the fuselage. They swapped out the battery and download the data it had recorded. Forty minutes later, the drone was ready to launch again.
After the crew ran through a pre-flight checklist, graduate student Travis Whitley held it in the air above his head and pitched it into the wind like a javelin once the engine was running. It climbed steeply into the clear blue sky in a spiral for its second pass over the nesting area.
Ifju had been working on micro air vehicles since the 1990s when he met Franklin Percival, the program leader of the Unmanned Aircraft Systems Research Program at UF, and got involved in this group about 12 years ago. Technology developed by Ifju's research lab has been patented and used by local drone builder Prioria Robotics.
Funding has come from a variety of sources, including the U.S. Geological Survey, the U.S. Army Corps of Engineers and other organizations that want surveys done.
The Nova is the same model that is sold commercially by Altavian, a Gainesville company started by several of Ifju's graduate students in 2011.
The unmanned aircraft has agricultural uses, as well. It can survey tomato crops for blight or orange groves for trees that are resistant to citrus greening.
The aircraft has evolved as the needs of the researchers have grown, Ifju said. Wildlife biologists, for example, wanted higher resolution and images, Ifju said.
The craft is equipped with a high-resolution, 10-megapixel camera that takes 1-inch-by-1-inch photos, an entire order of magnitude better than Google Earth's satellite cameras, which shoot 1-foot-by-1-foot squares.
“This is Google Earth on steroids,” Ifju said. “If the eggs in the nests had a high contrast with their background, we could actually count the eggs in the nest.”