K-Staters design and build a low-cost remote sensing tool for environmental studies

A Kansas State University research team is prototyping a small, inexpensive remote-control plane as a sensing tool, also known as an unmanned aerial vehicle, to collect environmental data. The team plans to test it over the Konza Prairie Biological Station near Manhattan this summer.

If the sensing tool performs as the team hopes, it will be made available to climate scientists, who would then be able to reconstruct it to obtain high-resolution images and reliable data.

The development of the sensing tool is part of a three-year research instrumentation project that began in fall 2005 with a $597,000 National Science Foundation grant.

The researchers are Dale Schinstock, assistant professor of mechanical engineering; Jay Ham, a professor of agronomy and an environmental biophysicist; and Doug Goodin, professor of geography and a remote sensing expert. Schinstock is in charge of developing the airframe and the remote control systems for the sensing tool, while Ham and Goodin will put it to work once it’s flight worthy.

According to the researchers, the sensing tool/unmanned aerial vehicle should be capable of “flying low and slow” just a few feet above the ground. The onboard payload of digital cameras, spectral radiometers and other remote sensing instruments will produce high-resolution images and data about small groups of plants and their environmental stress level.

At just 15 pounds with payload, the bantamweight hobby airframe with an 80-inch wingspan has been modified to house the remote sensing instruments in a carbon fiber-reinforced fuselage. A K-State graduate student designed and built an autopilot for first phases of the project. However, the researchers have opted for incorporating a commercially available autopilot so the sensing tool can be reproduced easily by others.

“This will be very easy to use. Its weight and size allow it to be launched by hand and flopped down in the grass for landings,” Schinstock said.

“Furthermore, we’re relying on an electric propulsion system that makes it extremely reliable and easy to use,” he said. “Battery power eliminates emissions and messy fuels that could compromise the data collection systems and greatly reduces vibration.”

According to Schinstock, the remote sensing tool will meet a need shared by thousands of environmental scientists worldwide. For just a few thousand dollars, researchers will have a way to collect data for small ecosystem sites at low altitudes and at very slow speeds. Until now, climate research has required costly, piloted airplanes and satellites for earth’s images and data, he said.

“Small remote-control planes can be put to work in a variety of environmental settings,” Ham said. “We want them to be comparatively cheap to build and operate. They’ll provide a data-collection tool that offers tremendous flexibility to users. We’re really developing a new tool for researchers that will allow them to go out and comprehensively map the vegetation in a field-sized area, for example, one square section.”

Schinstock said the concept of using the sensing tool for nonmilitary applications opens up many possibilities for collecting reliable data in tricky or dangerous settings, such as studying dispersal of a smoke plume during a prairie fire; checking smokestack emissions; counting livestock in the pens at a feedlot; or checking crop fields for problem areas, for example.

“We keep thinking of new civilian uses for it,” Ham said. He also said it will help his own research, which focuses on measuring the movement of gases between the prairie and the atmosphere.

Ham collects data via a mini-network of six meteorological towers on the Konza Prairie and the Rannells Flint Hills Prairie Preserve. The Konza towers are a component of the regional network, Ameriflux. Counterpart networks in Europe, Asia and Oceania also collect ecological data, which then flows to FLUXNET central locations, including Oak Ridge National Laboratory, for computer modeling the climate.

“Our role is to study the tallgrass prairie ecosystem and how land management impacts that ecosystem. In Kansas, we’re interested in how management decisions like grazing and burning, coupled with year-to-year weather variations, impact the movement of carbon dioxide between the surface and the atmosphere,” Ham said.

“Through these networks we’re trying to get a good understanding of all the major ecosystems in the world: grasslands versus Amazon forests versus African savannah versus tundra in Alaska,” Ham said.

“The earth’s atmosphere links all cultures and nations. By that, I mean that carbon dioxide emitted in China, for example, can impact the vegetation in North America or Europe and vice versa. Any decisions about climate change have to be based on a complete global analysis,” he said.

“Having this remote sensing tool will support a lot of environmental research that’s already going on in Kansas and also elsewhere,” Ham said. “Because it can fly as low as 15 feet and as slow as 30 miles per hour if necessary, we’re going to be able to see details that we cannot measure with a regular piloted aircraft.

“I think it will be possible not only to be able to say how much and what species of vegetation are there, but more importantly, to know the stress status of the plants: Is there water stress? Are the plants photosynthesizing at a high rate? We should be able to discern that information down to pixels representing less than a square foot of land area.”