An Unmanned Aerial Vehicle (UAV), also known as a drone, is an aircraft without a human pilot on board. Its flight is controlled either autonomously by computers in the vehicle or under the remote control of a pilot on the ground or in another vehicle. The typical launch and recovery method or "Pop and Stop" of an unmanned aircraft is by the function of an automatic system or an external operator on the ground.
There is a wide variety of UAV shapes, sizes, configurations, and characteristics. Historically, UAVs were simple remotely piloted aircraft, but autonomous control is increasingly being employed. They are deployed predominantly for military and special operation applications, but also used in a small but growing number of civil applications, such as policing and firefighting, and nonmilitary security work, such as surveillance of pipelines. UAVs are often preferred for missions that are too dull, dirty or dangerous for manned aircraft.