Although “sexy” isn’t the first adjective that pops into the minds of most people when they see us, here at the Roswell Flight Test Crew, we’ve had the good fortune to be involved in some of the sexiest FPV flying that there is to be done: monitoring structural and wildland firefighting exercises, conducting scientific research to help restore endangered species, and demonstrating cutting-edge technology.
All of that is über-cool—we’re incredibly grateful to have had those opportunities, and to the wonderful people who made it all possible—but the truth is that all of those applications represent a tiny fraction of the real work that sUAS or drones will do in the future.
According to the Association of Unmanned Vehicle Systems International (AUVSI), approximately 80% of the sUAS flying in the US during the next decade will operate within a single industry: agriculture.
Although it’s not especially glamorous or dynamic, sUAS have the potential to dramatically improve crop yields by alerting farmers to problems before they can be detected by any other means. On a hungry, crowded planet such as ours, that could be the difference between survival and starvation in the coming century.
Farming from Above
In the US, we annually lose 12% of our crops to pests and another 12% to disease. If we could eliminate these problems, we’d increase the output of our farms by one third. That’s food in the bellies of a lot of hungry people, both here and abroad.
Furthermore, the total value of our nation’s crops is nearly $140 billion per year, so even a modest improvement in yield would have a substantial economic impact—and sUAS can make that happen.
To understand how, we need to take a quick detour back to your freshman science class.
Let’s begin in the biology lab. As you will recall, the substance that gives plants their green color is called chlorophyll. It is responsible for absorbing the sun’s rays as part of a process called photosynthesis. By combining sunlight, water, and carbon dioxide through this process, the plant generates the fuel it needs to survive and grow.
Now we’re going to skip ahead a semester, from biology to physics. As Sir Isaac Newton taught us, when we look out at the world, we perceive the color of objects based on the specific frequency of light waves that they reflect back at us. This set of frequencies, between about 390 and 700 nanometers, constitutes the visible light spectrum.
Additionally, there are light waves that we cannot see with our own eyes because their wavelengths are either too long or too short. Light waves that are 700 nanometers or longer are referred to as “infrared,” while those that are 390 nanometers or shorter are called “ultraviolet.”
Now that you’re ready for the midterm, let’s take a look at what all of this means for the use of sUAS in agriculture. There is a correlation between plant health and chlorophyll levels: healthy plant, more chlorophyll. If the plant is affected by pests or disease, there is less chlorophyll. That makes perfect sense but, unfortunately, we can’t detect the declining levels of chlorophyll with the naked eye until the plant has already suffered some serious damage.
However, this decline also causes a change in the light waves the plant reflects outside of the visible light spectrum. Specifically, a plant with low levels of chlorophyll will reflect much more light in the near-infrared frequencies at roughly 700 nanometers than a healthy plant. That difference can be detected three or four days before the human eye can discern it.
Detecting the problem sooner means fixing the problem earlier, and decreasing the percentage of our crops lost to pests and disease. Furthermore, this technology will allow farmers to target water and fertilizer precisely where they are needed, rather than indiscriminately blanketing an entire field, improving efficiency.
Best of all, this can be done with conventional hobby airplanes. The near-infrared sensors are inexpensive and lightweight—easily within the carrying capacity of models that are for sale on the Internet today.
Being Sexy Isn’t Enough
That all sounds great, right? Farming dates back to the Neolithic Age and the first cultivated crops grown in the Fertile Crescent more than 10,000 years ago. Having a sense of that long history makes farmers dubious about how some piece of newfangled technology is supposed to change the world.
Helping them overcome that inherent skepticism was the challenge laid before us when we were invited to conduct a flight demonstration at the Unmanned Aerial Systems Precision Farming Forum in Yamhill County, Oregon, this past December.
The fields were bare and the ground was frozen solid, so it was obvious that we weren’t going to be doing an actual crop survey in the near-infrared spectrum, but we didn’t want to merely show up with one of our FPV multirotors and fly around outside the meeting hall. People would no doubt be intrigued by our peculiar-looking flying machines, but we wanted to give them a sense about how an sUAS could allow them to see things that were invisible to the naked eye.
To accomplish this goal, we brought out our FLIR Tau2 640 thermal-imaging camera. The FLIR is sensitive to wavelengths between 8,000 and 14,000 nanometers. This is much too deep in the infrared spectrum to be useful for this type of crop survey, but absolutely brilliant for finding lost hikers and tracking the progress of wildfires.
Sensor in hand, we needed a target, something warm enough to show up on the FLIR, but small enough that it wouldn’t draw attention to itself out on the field where we were giving our demonstration. An electric space heater would have worked great, but the orange glow and the extension cord would have been a dead giveaway.
We finally stumbled on the idea of using those disposable hand warmers. When you break the airtight seal and expose them to the air (or more specifically the oxygen in the air), iron particles inside the pouch undergo an accelerated rusting process, giving off heat in an exothermic reaction.
A few minutes before the farmers emerged into the frosty morning air, we ripped open the warming packets and laid them out in patterns on the ground. With our audience huddled under propane heaters, we launched the RQCX-5 Firefly into the air. The live video feed patched onto a large, flat-screen monitor that was set up for the demonstration.
We made one pass over the field with a visible light camera active, then switched over to the FLIR. The warming pouches, lost among the frost and snow in the visible light image, suddenly appeared as a glowing patch on the ground—just like a distressed plant on a near-infrared image.
A New Frontier
As a part of its new program to embrace the FPV community, AMA plans to provide support for light commercial and purposeful-use applications of RC aircraft; the agricultural use of sUAS is at the top of the list. This will give the AMA a chance to establish a relationship with a multibillion dollar industry, while simultaneously educating a new class of users about safe, responsible flying and literally helping to feed the world.
This is an opportunity unlike any that the AMA has had in its entire 77-year history, and it will likely open up new frontiers for the organization’s members as well, given their depth of knowledge about how to build, maintain, and fly these systems. Even the FAA has recognized the potential.
In a statement issued on November 25, 2013, FAA official Les Dorr stated that, “Farmers may operate an unmanned aircraft over their own property for personal use and guidelines for the operations of model aircraft, such as those published by the Academy of Model Aeronautics, may be used by farmers as reference for safe model UAS operations.”