New drone aircraft to act as crop scout
By Larry Dreiling
As producers undertake spring planting, it's useful to look at what is ahead of them in the near future as they complete their purchases of seed, fertilizer, and crop protection products.
Likewise, it's rather fun to see what may be ahead just a few short years from now as the research community takes new technology and reduces it from the "gee whiz" stage down to a useful product or service.
Unmanned Aerial Vehicles, or drones, lately have become the talk of modern warfare. Since 2004 the U.S. Air Force and Central Intelligence Agency have been using UAVs to strike at terrorist targets, primarily in Pakistan, according to the Bureau of Investigative Journalism.
Using Global Positioning System navigation and loaded with bombs, these drones have struck more than 300 targets. Estimates indicate they've taken out more than 2,000 terrorists in the process with no loss of American lives.
Now this drone technology is moving down onto the farm.
The Kansas State University Department of Agronomy recently purchased a new MAJA Unmanned Aircraft System, with the intent of installing imaging systems on it for studying plant productivity, monitoring plant growth stages, assessing plant health, and mapping plant composition for characterizing changes in distribution of invasive and toxic plant species.
Kevin Price, Ph.D., a K-State professor in agriculture/natural resources/remote sensing/GIS has teamed up with a talented radio-controlled aircraft hobbyist, Deon van der Merwe, Ph.D., an associate professor and head of the Toxicology Section at the K-State Veterinary Diagnostic Laboratory, to develop a very high-resolution airborne imaging system that will carry a near infrared, and a natural color camera at the same time.
It will also be equipped with a first-person viewing video camera that will allow the researchers to view the area over which the plane is flying in real time, while recording high resolution images of the over flight area below.
The cost of the MAJA, which is battery powered, Price said, was about $300. The cameras cost extra. The research is being funded by a $40,000 grant to the K-State Agronomy Department.
"It won't be too many years from now that crop scouts will be using this technology instead of four-wheelers," Price said. "The GPS units on these planes are so small that they will be able to load their data and it will tell the plane how to fly from one point to another transecting the entire field for the information they need."
Once a Certificate of Authorization is obtained from the Federal Aviation Administration, the aircraft will be equipped with autonomous flying capabilities so it can be flown to predetermined locations within a line of sight.
Flight lines can be predetermined and uploaded to the autopilot, and the plane flown along these lines to create picture coverage of areas or fields of interest. The images can be digitally "stitched" together to form whole field mosaics.
This system will generate 12 megapixel images in NIR infrared, red, green, and blue wavelengths, which will assist in measuring crop growth, weed development and insect infestations.
"This will help us create mosaic images using the natural color camera with an overlay of the NIR in the different wavelengths," Price said. "This multi-spectral photography combined with the use of computer techniques to capture estimates of things like net primary productivity of biomass, or types of vegetation.
"We can also do things like map for distribution of sericea lespedeza invasions, or find old world bluestem grass. There's dozens and dozens of applications."
It can be flown up to several thousand feet or more above the ground, but for safety reasons, it will be flown below 600 feet--and mostly below 400 feet. That will permit the capture of very detailed images of features of interest on the ground.
"One of the best things we'll be able to do is phenotyping, an indirect way of determining genetics," Price said. "One of the challenges for crop breeders now is selecting crosses from thousands and thousands of choices. They have to go into the field and eyeball what crosses work best in offering desirable traits. If they're lucky, they'll survey a whole field of plots just once over the course of a growing season.
"Instead, we can fly the plane over the nursery plots every week or so and look at the growth patterns of all the test plots. We can develop a chronological score to see which plants are growing more rapidly than others, which are producing more biomass, and we can even develop models over time to estimate yields of that crop. This way, the breeder than have a faster, better way of determining seed sources."
Price also said he is working with the Kansas Forest Service to look at the BTUs produced by burning Eastern Red Cedar trees as a source for electrical generation. Using wood chips for electrical generation is nothing new in Kansas, as Frito-Lay's Topeka plant uses them in sustainable power consumption.
"We plan to develop a whole new industry of harvesting these trees as biofuel," Price said. "We think that buying using these in electrical generation we can cut energy costs by one-third and recycling carbon rather than putting carbon out into the atmosphere."
The pixel size will be from 0.25 to 2 inches (depending on whether a telephoto or wide angle lens setting is used) for images captured at 400 feet above the ground, so individual plants can be observed and studied.
While Price brings the science, van der Merwe brings his decades-long experience in flying model aircraft to the research. Price said having a person with that experience is crucial to developing the strategies needed to teach others how to use the UAS as a holistic system for serious work, and not as a toy.
"This is an application of things I learned as a hobby," van der Merwe said. "A lot of people use this for first-person view cameras. These are perfect for use for research.
Kevin and I share an interest in remote sensing, so it was natural for us to work together."
Also being tested is a hexacopter, a small, six rotor, flying object about the size of the average desktop.
Both the MAJA and the hexacopter are built by Bormatec, a German company specializing in these type of precision UASs. The MAJA is made of expanded polypropylene, a denser, but lighter form of product you'd find in a foam drink cup.
The airframe is partially cut in two with a lightweight composite hinge, allowing van der Merwe to open the airframe to expose two spaces in which to securely nestle the cameras.
"The empty weight of the airframe is about 1.5 kilograms," van der Merwe said. "With a complete load, it's about three kilograms. With the EPP airframe, and no wheels, we can land the UAS in a field and it won't crash. It's quite resilient."
The hexacopter, Price said, can carry cameras that can bring that pixel size down to centimeters, because it's a stable platform. Using calibration panels on the ground, pixels can be converted to percent reflectance values to normalize images for date-to-date changes in incoming solar radiation.
"Using the autonomous mode will allow us to get those very accurate images," van der Merwe said. "As we work further on the research, and as the cost of the equipment continues to decrease as interest rises, a crop scout will be able to get some very high quality images at a much lower cost. The only limitation is capability of the aircraft and the location of where you fly."
Because the drone is being used in research in an autonomous mode by a program aboard the UAV rather than primarily a handheld radio control, an FAA Certificate of Authorization is required.
"We are in the process of getting an FAA Certificate of Authorization so the plane can be safely used in areas approved by the FAA," Price said. "This certificate requires the pilot in command to hold a Pilot Certificate, and it requires preauthorization of areas to be flown by the FAA."
Says van der Merwe, "For the hobbyist, there aren't many restrictions on the use of these, but for research and commercial use there's different levels of restrictions for use, for example, in cities and near military bases (K-State is near the U.S. Army's Fort Riley), but in mostly rural areas there are fewer restrictions.
"This is a technology that will be of great use for us in Kansas with our wide open spaces."
Supporting faculty on the research include molecular breeding specialist Jesse Poland, Ph.D., theoretical plant modeler Steve Welch, Ph.D., wheat breeder Allan Fritz, Ph.D., and soybean breeder Bill Schapaugh, Ph.D.
Graduate students currently involved in the project are David Burchfield (an M.A. student in geography), who will be using these data to study prairie conditions, and Nan An (a Ph.D. student in agronomy), who is studying Flint Hills Tallgrass productivity.
"We have also been working with Josh Brungardt and Dr. Kurt Barnhart of the K-State-Salina Aviation Department with matters related to FAA flight approval," Price said.
Larry Dreiling can be reached by phone at 785-628-1117, or by email at firstname.lastname@example.org.