Jack Elston 2016-06-29 04:37:45
Manned aviation has been used for agricultural applications for decades, so why all the sudden interest in unmanned aircraft systems (UAS)? There are crop dusters for spray applications, manned aircraft equipped with cameras capable of aerial photography including hyperspectral imaging, and a plethora of satellite measurements to choose from. As you might guess, the answer is not simple. It may be a surprise, but UAS have been involved in agriculture since the 1990s. One of the earliest examples can be found in spray applications for rice. The typically rugged terrain that is terraced for rice doesn’t lend itself to simple, uniform application of fertilizers and pesticides, so a motorcycle-size unmanned helicopter was developed to navigate the difficult terrain and provide precise delivery of the needed additives. While this technology was successful in accomplishing its primary application, it wasn’t adopted for use in other crops or regions because it was simply too expensive and maintenance-intensive when compared to more traditional application methods. The consumer electronics revolution helped to bring about the next generation of agricultural UAS. Miniaturization of the sensors necessary for guidance and imaging occurred simultaneously with improved battery energy density. This allowed the creation of vehicles small enough to be simple to operate while still carrying a useful payload and sufficient flight time. With these advances, on-demand data became a reality. Additionally, the continued push for “connectivity” throughout the U.S. allowed collection of crop and management data in near realtime, which is essential for precision agriculture. Finally, the migration to cloud computing meant that an abundance of computing power was available to average citizens. Farmers no longer needed to rely on an outdated home PC to provide the answers they needed; instead, they had access to server farms and online experts. So really, UAS are only a small part of a vertical technology chain, but they’re a great way to get on-demand data from a unique viewpoint. Where is all this headed? Given that precision agriculture is all about the data, why care about UAS? It’s because they’re rapidly becoming the least expensive option for on-demand data. We can now collect NDVI and full visible spectrum maps every hour, instead of only few times a season with manned aviation or up to once a day but at low resolution with satellites. With all this high temporal and spatial resolution data, we’re figuring out better ways to determine plant and animal health. Ultimately, that will lead to more efficient farming and better yields. Determining plant stress ASABE member Jose Chavez and his team at Colorado State University (CSU) are working to develop models that use canopy temperature as an indicator of plant stress. They’re hoping that routine temperature observations will be able to determine watering schedules and techniques. Our company, Black Swift Technologies LLC, worked with CSU to develop a custom UAS solution containing an EO camera, multispectral camera, shortwave IR camera, and longwave IR sensor. The IR sensor was used to support the model development, while the other sensors allow the team to validate their assumptions using independent sensors and methods. Experiments are currently in progress, and so far the results have shown an encouraging correlation between canopy temperature and plant stress. Managing variable-rate irrigation Black Swift Technologies has also worked with ASABE member Wayne Woldt, director of the NU-AIRE laboratory at the University of Nebraska-Lincoln (UNL), to develop typical approaches to agricultural flight profiles. In addition, Black Swift Technologies worked with the UNL team to integrate a sensor pack for variable-rate irrigation (VRI) into our SwiftPilot autopilot system. Tight integration of the autopilot and payload allows the sensors to be triggered automatically and logged at the appropriate rates. This precision is required for mosaicking of images, creating a data product that provides a complete view of a field for irrigation management purposes. The current focus of the UNL team is to use these images to improve the use of VRI technology. While VRI equipment is available from irrigation manufacturers, the understanding of where, when, and how much irrigation water to apply is still underdeveloped. Measuring soil moisture Both of the above applications use indirect methods and complex models to determine soil moisture. The predominant method in practice today is still direct measurement, using time-intensive soil moisture probes. In collaboration with the Center for Environmental Technology at the University of Colorado under an ongoing NASA grant, Black Swift Technologies is developing UAS technology that will significantly improve the measurement of soil moisture from the air. This new technology is a simple-to-operate system with a highly capable passive L-band microwave radiometer that provides measurements of volumetric soil moisture content over plot-size areas. The technology employed in this small aircraft is based on concepts similar to NASA’s Soil Moisture Active Passive (SMAP) satellite, which was designed to provide global soil moisture maps at a much larger scale. The soil moisture mapping UAS is complementary to this mission and provides local, high-resolution maps of soil moisture. Black Swift’s expertise enabled tight integration of the sensor with the UAS avionics and airframe to enable precise flight control of low-altitude missions in the range of 15 to 30 m (50 to 100 ft) above ground level. Low-altitude flight is essential for the sensor to accurately map soil moisture down to about 15 to 20 cm (6 to 8 in.) depth at up to 15 m resolution. A first prototype of the instrument was flown and validated at a NASA instrumented test site in Canton, Oklahoma, in the fall of 2015, yielding encouraging results. The soil moisture maps generated from data provided by this aircraft were shown to correlate well with in situ probes. On-going field campaigns in the summer of 2016 will focus on flying the sensor over different types of crops and soil conditions to characterize and validate the sensor for the large range of conditions it may encounter in agriculture. The team is looking to partner with crop consultants and other agriculture experts to improve water use efficiency with this technology while maintaining or increasing yields. More information on the system can be found at http://SoilMoistureMap.com. Weather prediction Additionally, Black Swift Technologies has worked with several national laboratories and the University of Colorado to improve the ability of UAS to perform atmospheric sampling. Through advanced efforts such as the 2010 Verification of the Origins of Rotation in Tornadoes Experiment 2 (VORTEX 2), the capabilities of UAS have been expanded to sampling areas beyond the reach of conventional radar and weather balloon technology. Improved knowledge of the atmosphere will further improve weather prediction. When combined with better knowledge of soil moisture content, this technology can provide better irrigation schedules as well as warnings about catastrophic events, such as flash floods. Reliability and cost reduction Finally, while several off-the-shelf UAS options are now available for collecting visual and multispectral data, the most immediate change in UAS will be continued improvements in autonomy and reliability. Currently, most of these vehicles are still prone to crashing, and they are difficult to operate. We’ve worked extensively to solve many of these issues. Several new techniques—including sensor redundancy, fault recognition and mitigation, the introduction of maintenance schedules, and the use of automatic processes to reduce the burden on the “human in the loop”—have already been incorporated into our aircraft. Although UAS might seem like little more than toys, the continued advances in their capabilities, combined with the enormous investments that continue to be made in the data infrastructure surrounding them, guarantee that UAS will become a part of the future of agricultural applications. In a business where every cent counts, knowing exactly when, where, and what to do—and what not to do—will make all the difference in profitability. Entrepreneur Jack Elston Jack Elston has over thirteen years of experience working in the UAS field and is the CEO/President and co-founder of Black Swift Technologies (BST). Elston is also the technical lead on all avionics work at BST, including the creation of a low-cost, highly capable autopilot system along with unique networking technologies to enable cooperative control of UAS. Elston received his PhD from the University of Colorado Boulder in 2011, developing a system and algorithms for UAS sampling of tornadic supercell thunderstorms. This work culminated in the design of a UAS used to conduct the first-ever intercept of a tornadic supercell thunderstorm by an unmanned aircraft as part of the NSF and NOAA funded VORTEX2 project. His research demonstrated the utility of integrating payloads into UAS to conduct meaningful scientific research. Elston’s other work at the University of Colorado involved the development of four different unmanned aircraft systems at the Research and Engineering Center for Unmanned Vehicles while conducting over 300 flight experiments. He also co-authored over 70 applications for Certificates of Authorization allowing legal operation of UAS within the national airspace. BST uniquely couples avionics expertise with consulting services. BST produces its own line of customizable autopilots, ground stations, and supporting avionics that enable customers to fly and coordinate UAS with greater precision and simplicity. Concurrently, BST offers consulting services for customers attempting to navigate the ever-dynamic and often confusing application process for legal access to U.S. airspace, as granted by the Federal Aviation Administration through Certificates of Authorization and Section 333 Exemptions. More information on this service can be found at http://ApprovedFlight.com. Jack Elston, Founder and CEO, Black Swift Technologies LLC, Boulder, Colo., USA, email@example.com.
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