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Current technologies employed for use of small, unmanned aerial systems (sUAS), or “drones”, for remote sensing (RS) activities that support the information needs of agricultural operations are expensive, provide relatively small geographic coverage, and typically produce data of limited scientific quality. Research is currently underway that will someday yield sense-and-avoid technologies that will enable sUAS to detect and safely avoid potential collisions with conventional and UAS air traffic. Other on-going research will result in the development of a nation-wide air traffic management system that will fully integrate UAS flights into US airspace. Together, these two research products will allow safe, long-duration sUAS flights, or flights that are “beyond-visual-line-of-sight” (BVLOS). As BVLOS technologies come on line, there will likely be a decrease in the per-acre cost of sUAS-based RS, which, in turn, will spur incentives for development of sUAS that can fly much further and cover much more area than platforms that are now in common use. A decrease in per-acre RS costs well likely result in an increased demand for RS technology in support of agricultural operations. However, adoption of BVLOS technologies that support greater access to US airspace for agricultural RS applications will present challenges to commonly used sUAS RS approaches that do not scale well as sUAS geographical coverage and flight times increase. Of particular concern are radiometric calibration of imagery and the cost and time required for generation of high-quality orthomosaics, point cloud algorithms, effects of temporal changes in surface spectral and thermal response, and delivery of time-sensitive image products to the grower. This paper examines the implications of these future challenges for sUAS RS in agriculture and offers insights into their solution that are topics of research today. In addition to examining the topics of radiometric calibration and orthorectification, other aspects, such as field protocols in the design and execution of flights and the need for additional on-board sensors, will be discussed.
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