An Unmanned Aerial Vehicle for Rangeland Photography

Abstract

Abstract Because of its perceived impracticality and expense, aerial photography from unmanned aerial vehicles (UAVs) remains virtually unused as a rangeland management tool. This underuse suggested 2 objectives. The first was to develop a UAV from off-the-shelf components that could acquire low-altitude large-scale photography for rangeland documentation. The second was to assess the UAV flight characteristics. A remotely controlled UAV suitable for 35-mm photography was built in 56 hours at a cost of $1 480. In a 2-year test period, the UAV successfully completed 100+ sorties at elevations ranging from 10 m to 1 000 m above ground. The average distance required for takeoff is 18.2 m whereas landing requires an average of 22.5 m. Average UAV airspeed at takeoff is about 11.4 m·s −1 . Typical cruise speed during photograph acquisition is 13.8 m·s −1 , resulting in 6.9 mm of blur from forward-image motion. The UAV is an inexpensive tool for monitoring rangeland condition from an aerial perspective. It is currently being used to map squarrose knapweed ( Centaurea virgata Lam. ssp. squarrosa Gugl.) density at several rangeland sites in Utah.