Unmanned aerial vehicles (UAVs), or drones, are operated remotely or autonomously without a human pilot on board. UAVs are also sometimes called unmanned aircraft systems (UAS) to highlight the components other than the vehicle itself that are common to a UAV, including a control system and a datalink between the vehicle and the control system.

UAVs are used in a wide range of civil and military applications, in which they mitigate the risk inherent in traditional manned aircraft surveillance and provide increased performance without the restrictions created by a human pilot. One common role is remote observation or surveillance for such functions as natural resource exploration, disaster relief, wildlife conservation, archeological surveys, and other scientific research. UAVs are also used in military operations for logistics, reconnaissance, and combat attacks.

The video below provides a general overview of UAV operation.

Video credit: Northrop Grumman

Specifications

Unmanned aerial vehicles have a number of key values that define their performance, including:

• Weight – the vehicle’s relative mass including all onboard systems with or without fuel or batteries
• Max ascent speed – the highest speed that the vehicle can rise through the atmosphere
• Max descent speed – the highest speed that the vehicle can move down through the atmosphere
• Max speed – the top horizontal speed attainable by the craft
• Max service ceiling above sea level – the highest altitude that the vehicle is designed to operate at
• Max flight time – the duration of flight that the vehicle is capable of, determined by power expenditure and available fuel or power reserves
• Operating temperature – the range of environmental temperatures at which the craft can operate
• Hover accuracy – the vertical altitude and horizontal distance within which the vehicle can maintain its position compared to the target location
• Dimensions – the spatial sizes of length, width, and height of the vehicle, in addition to specific measurements like wing span, diagonal size, propeller diameter, etc.

Components

Unmanned aerial vehicles have a variety of equipment that function together to accomplish the tasks required by the UAV operator. Large UAVs are often powered by traditional aircraft engines, while small UAVs are usually powered by lithium-ion batteries. Onboard computing hardware may include system on a chip (SOC) integrated circuits or single board computers (SBS).

UAV sensors capture data about both the external environment and the internal operating status of its own systems. This information is utilized by the autonomous control system to execute flight programs or relayed to a remote operator for operation of the craft. The communications system transmits data between the vehicle and ground control stations. A radio frequency system sends and receives information such as system status, location, and video.

The software flight stack controls various functions of a UAV and includes firmware, middleware, and the overall operating system. Firmware handles low level execution of machine instructions by the processor, middleware is responsible for functions such as navigation and flight control, and the operating system carries out processor intensive functions like obstacle avoidance and decision making.

Autonomy

Many unmanned aerial vehicles have autonomous capabilities controlled by artificial intelligence. UAVs offer various degrees of autonomy by accepting sensor data and initiating action through multiple control loops. The base layer algorithmic control consists of managing flight stability and maneuverability, data communications, and power distribution. The second layer contains system management, navigation, and path planning. The most sophisticated level of autonomous control involves mission planning, cognitive autonomy that allows UAVs to make and change tactical and strategic goals with little outside guidance.

Applications

Unmanned aerial vehicles serve in a wide range of roles, including military, commercial, and recreational functions. Military applications include reconnaissance, attack, defense, and targets for training. Civil applications include recreational and hobby use, commercial or professional aerial surveillance, motion picture filming, journalism, law enforcement, search and rescue, research, conservation, pollution monitoring, oil and gas surveying, disaster relief, agriculture, archeology, and cargo transport.

Image credits:

DJI | Northrop Grumman