Multirotors in the rainforest.

Multirotors in the rainforest.

Jonathan Dandois, postdoctoral research fellow for the Smithsonian Tropical Research Institute in Panama, studies the Barro Colorado Island’s rainforest canopy’s cycle of producing fruit, flowers and leaves and, for him, the dawn of multirotor technology was a game changer.

“[Before multirotors research was conducted] primarily through ground-based surveys by field personnel visiting a sample of trees and looking up at tree crowns,” Dandois said. “Now we can collect high resolution data for all the canopy trees over a plot in less than an hour.”

Dandois uses multirotors to “produce high resolution images mosaic maps of the forest every week of a 1,000 meter by 500 meter permanent forest plot.” It is the most practical form of imaging remote sensing for him to see changes in the forest canopy, as well as individual trees.

“I wanted to be able to collect high resolution aerial imagery over landscapes on-demand at high frequency and low cost,” Dandois said. “Multirotors fit just right.”

Dandois flies a simple point and shoot digital camera on his multirotor, with the shutter button secured with a velcro strap so it will shoot continuously at 10 MP and two frames per second. He uses 3DR Pixhawk flight control system and a back-up GPS tracker.

“Our goal is to collect imagery of the canopy in the same exact way every week with a technically simple and autonomous system,” Dandois said.

In the past six years, Dandois estimates he’s spent close to $60,000 on multirotor projects.

“For cameras, I’ve kept it to the cheap point, less than $200,” Dandois explained.

He has upgraded from APM to Pixhawk, the battery pack in his tx to a lipo pack for a longer life, and is now running 16 inch props for longer flights. He changed from an Octo configuration to a Quad configuration in order to reduce weight is using a Spectrum DX7s tx because it’s comparable and easy to use with 3DR flight controllers. He also switched to MaxAmps for longer flight times.

MaxAmps batteries have a greater power density that allows us to achieve longer flight times,” Dandois said. Jonathan has a selection of 4-cell MaxAmps LiPo batteries he uses to power his multirotors. He is currently using the 22000mah 4s, 11000mah 4s and 6500mah 4s.

He explained that means he and his team can cover larger areas of forest in a single mission and launch from better take of locations and improved flight time means more data.

“No other brands have the same density, size and flight time performance,” Dandois said.

In the future, Dandois hopes to see cheaper systems that can fly longer and can take-off, fly a mission, land, download data, and recharge batteries – all on a fixed schedule for “truly automated remote sensing.”

Dandois has flown over China, Panama, Costa Rica and New Jersey, but he said his favorite place to fly was in Baltimore, Maryland where he flew over 120 flights in a three month period for research.

“I could drive my car right into the middle of the field to set up my ground control station and easily conduct five to ten back-to-back autonomous flights over the forest with no distractions and a nice view,” Dandois said.


-Jessica Else/Blogger –