A vehicle is classified as an unmanned aerial system (UAS) when there is no person on board to guide controls, or decide direction or speed of the vehicle. UAS are equipped with on-board flight and navigation controls to be piloted remotely or through Global Positioning System (GPS) waypoints in autopilot mode. In general, the shape and size of the system governs classification of UAS into four different types (explained below). Proposed regulations from the Federal Aviation Administration (FAA) classify a UAS with gross weight of less than 55 lbs (25 kg) as a small UAS (sUAS). Most of the newer sUAS are controlled from ground stations using remote control, multi-channel bidirectional communication systems, which generally use a frequency of 2.4 GHz in the United States. Most systems also have autopilot and auto land capability. From an application standpoint, sUAS, which are the focus of this fact sheet, are integrated with sensing modules on board that appear to have a wide range of applications in agricultural production management when combined with soil, weather, and relevant crop growth information.
Types of Unmanned Aerial Systems
Shape, size, flight time, control type, and payload capabilities influence the selection of sUAS for agricultural applications. The sUAS can be classified into four types: parachute, blimp, rotocopter, and fixed-wing systems. Each type has favorable and unfavorable attributes, depending on application.
Motorized parachutes are easy to fly in no-wind conditions with varied payload, but are challenging to operate under windy conditions. They can be maneuvered at low speeds and offer longer flight time compared with the other three types discussed in this article. However, they cannot hover at a chosen point of interest and need a runway for take-off and landing.
Blimps commonly are used in commercial advertising and may be used in agricultural aerial imaging applications. Blimps can hover in place so it is possible to take clear images of selected areas. However, blimps may be difficult to fly in windy conditions and they are slow to move from one location to another.