An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without a human pilot aboard. UAVs are a component of an unmanned aircraft system (UAS); which include a UAV, a ground-based controller, and a system of communications between the two. The flight of UAVs may operate with various degrees of autonomy: either under remote control by a human operator or autonomously by onboard computers.
Compared to manned aircraft, UAVs were originally used for missions too “dull, dirty or dangerous” for humans. While they originated mostly in military applications, their use is rapidly expanding to commercial, scientific, recreational, agricultural, and other applications, such as policing, peacekeeping, and surveillance, product deliveries, aerial photography, agriculture, smuggling, and drone racing. Civilian UAVs now vastly outnumber military UAVs, with estimates of over a million sold by 2015, so they can be seen as an early commercial application of autonomous things, to be followed by the autonomous carand home robots.
Multiple terms are used for unmanned aerial vehicles, which generally refer to the same concept.
The term drone, more widely used by the public, was coined in reference to the early remotely-flown target aircraft used for practice firing of a battleship’s guns, and the term was first used with the 1920’s Fairey Queen and 1930’s de Havilland Queen Bee target aircraft. These two were followed in service by the similarly-named Airspeed Queen Wasp and Miles Queen Martinet, before ultimate replacement by the GAF Jindivik.
The term unmanned aircraft system (UAS) was adopted by the United States Department of Defense (DoD) and the United States Federal Aviation Administration in 2005 according to their Unmanned Aircraft System Roadmap 2005–2030. The International Civil Aviation Organization (ICAO) and the British Civil Aviation Authorityadopted this term, also used in the European Union’s Single-European-Sky (SES) Air-Traffic-Management (ATM) Research (SESAR Joint Undertaking) roadmap for 2020. This term emphasizes the importance of elements other than the aircraft. It includes elements such as ground control stations, data links and other support equipment. A similar term is an unmanned-aircraft vehicle system (UAVS) remotely piloted aerial vehicle (RPAV), remotely piloted aircraft system (RPAS). Many similar terms are in use.
A UAV is defined as a “powered, aerial vehicle that does not carry a human operator, uses aerodynamic forces to provide vehicle lift, can fly autonomously or be piloted remotely, can be expendable or recoverable, and can carry a lethal or nonlethal payload”. Therefore, missiles are not considered UAVs because the vehicle itself is a weapon that is not reused, though it is also unmanned and in some cases remotely guided.
The relation of UAVs to remote controlled model aircraft is unclear. UAVs may or may not include model aircraft. Some jurisdictions base their definition on size or weight, however, the US Federal Aviation Administration defines any unmanned flying craft as a UAV regardless of size. For recreational uses, a drone (as apposed to a UAV) is a model aircraft that has first person video, autonomous capabilities or both.
Most UAVs use a radio frequency front-end that connects the antenna to the analog-to-digital converter and a flight computer that controls avionics (and that may be capable of autonomous or semi-autonomous operation).
Radio allows remote control and exchange of video and other data. Early UAVs had only uplink. Downlinks (e.g., realtime video) came later.
In military systems and high-end domestic applications, downlink may convey payload management status. In civilian applications, most transmissions are commands from operator to vehicle. Downstream is mainly video. Telemetry is another kind of downstream link, transmitting status about the aircraft systems to the remote operator. UAVs use also satellite “uplink” to access satellite navigation systems.
The radio signal from the operator side can be issued from either:
- Ground control – a human operating a radio transmitter/receiver, a smartphone, a tablet, a computer, or the original meaning of a military ground control station (GCS). Recently control from wearable devices, human movement recognition, human brain waves was also demonstrated.
- Remote network system, such as satellite duplex data links for some military powers. Downstream digital video over mobile networks has also entered consumer markets, while direct UAV control uplink over the celullar mesh is under researched.
- Another aircraft, serving as a relay or mobile control station – military manned-unmanned teaming (MUM-T).
ref: wikipedia.org