An unmanned aerial vehicle for range management. Hardin, Perry^*,1, ¹ BYU Department of Geography, Provo, UT, USA

ABSTRACT- Large-scale aerial photography from unmanned aerial vehicles (UAVs) remains virtually unused as a rangeland tool. To remedy this underutilization, this research had two objectives; 1) to develop a UAV from off-the-shelf components that could acquire low-altitude large-scale photography for documenting rangeland and, 2) to determine the feasibility of using the UAV under operational conditions. A remotely controlled UAV suitable for 35 mm photography was built in 56 hours at a total equipment cost of $1380. The UAV has successfully completed 100+ sorties at elevations ranging from 10 to 1850 m above local terrain (16 to 2070 m above sea level). Typical cruise speed during picture acquisition is 13.8 m/s. At that groundspeed, image blur from forward aircraft motion is 6.9 mm. Because of this low value, resolution is almost entirely dependent on aircraft altitude above ground. Picture quality is uniformly excellent, and patterns not discernable on the ground are frequently visible on the air photography. The UAV has been used to successfully map the location of squarrose knapweed ( Centaurea virgata Lam. ssp. squarrosa Gugl.) at four range sites in Utah as well as acquire range condition photography of sites in New Mexico, Texas, Utah, and Colorado.

KEY WORDS: aerial photography, unmanned aerial vehicles, range documentation