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 car and home robots.
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.
The Israeli Tadiran Mastiff, which first flew in 1973, is seen by many as the first modern battlefield UAV, due to its data-link system, endurance-loitering, and live video-streaming.
In 1849 Austria sent unmanned, bomb-filled balloons to attack Venice. UAV innovations started in the early 1900s and originally focused on providing practice targets for training military personnel.
In the 1973 Yom Kippur WarIsrael used UAVs as decoys to spur opposing forces into wasting expensive anti-aircraft missiles.
In 1973 the U.S. military officially confirmed that they had been using UAVs in Southeast Asia (Vietnam). Over 5,000 U.S. airmen had been killed and over 1,000 more were missing or captured. The USAF 100th Strategic Reconnaissance Wing flew about 3,435 UAV missions during the warat a cost of about 554 UAVs lost to all causes. In the words of USAF GeneralGeorge S. Brown, Commander, Air Force Systems Command, in 1972, "The only reason we need (UAVs) is that we don't want to needlessly expend the man in the cockpit." Later that year, General John C. Meyer, Commander in Chief, Strategic Air Command, stated, "we let the drone do the high-risk flying ... the loss rate is high, but we are willing to risk more of them ... they save lives!"
During the 1973 Yom Kippur War, Soviet-supplied surface-to-air missile batteries in Egypt and Syria caused heavy damage to Israeli fighter jets. As a result, Israel developed the first UAV with real-time surveillance. The images and radar decoys provided by these UAVs helped Israel to completely neutralize the Syrian air defenses at the start of the 1982 Lebanon War, resulting in no pilots downed. The first time UAVs were used as proof-of-concept of super-agility post-stall controlled flight in combat-flight simulations involved tailless, stealth technology-based, three-dimensional thrust vectoring flight control, jet-steering UAVs in Israel in 1987.
Manned and unmanned aircraft of the same type generally have recognizably similar physical components. The main exceptions are the cockpitand environmental control system or life support systems. Some UAVs carry payloads (such as a camera) that weigh considerably less than an adult human, and as a result can be considerably smaller. Though they carry heavy payloads, weaponized military UAVs are lighter than their manned counterparts with comparable armaments.
Small civilian UAVs have no life-critical systems, and can thus be built out of lighter but less sturdy materials and shapes, and can use less robustly tested electronic control systems. For small UAVs, the quadcopter design has become popular, though this layout is rarely used for manned aircraft. Miniaturization means that less-powerful propulsion technologies can be used that are not feasible for manned aircraft, such as small electric motors and batteries.
Control systems for UAVs are often different than manned craft. For remote human control, a camera and video link almost always replace the cockpit windows; radio-transmitted digital commands replace physical cockpit controls. Autopilot software is used on both manned and unmanned aircraft, with varying feature sets.
The primary difference for planes is the absence of the cockpit area and its windows. Tailless quadcopters are a common form factor for rotary wing UAVs while tailed mono- and bi-copters are common for manned platforms.
Position and movement sensors give information about the aircraft state. Exteroceptive sensors deal with external information like distance measurements, while exproprioceptive ones correlate internal and external states.
Non-cooperative sensors are able to detect targets autonomously so they are used for separation assurance and collision avoidance.
Degrees of freedom (DOF) refer to both the amount and quality of sensors on-board: 6 DOF implies 3-axis gyroscopes and accelerometers (a typical inertial measurement unit – IMU), 9 DOF refers to an IMU plus a compass, 10 DOF adds a barometer and 11 DOF usually adds a GPS receiver.
UAVs employ open-loop, closed-loop or hybrid control architectures.
Open loop—This type provides a positive control signal (faster, slower, left, right, up, down) without incorporating feedback from sensor data.
Closed loop – This type incorporates sensor feedback to adjust behavior (reduce speed to reflect tailwind, move to altitude 300 feet). The PID controller is common. Sometimes, feedforward is employed, transferring the need to close the loop further.
Automatic flight involves multiple levels of priority.
UAVs can be programmed to perform aggressive manœuvres or landing/perching on inclined surfaces, and then to climb toward better communication spots. Some UAVs can control flight with varying flight modelisation, such as VTOL designs.
UAVs can also implement perching on a flat vertical surface.
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:
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).
ICAO classifies unmanned aircraft as either remotely piloted aircraft or fully autonomous. Actual UAVs may offer intermediate degrees of autonomy. E.g., a vehicle that is remotely piloted in most contexts may have an autonomous return-to-base operation.
Basic autonomy comes from proprioceptive sensors. Advanced autonomy calls for situational awareness, knowledge about the environment surrounding the aircraft from exterioceptive sensors: sensor fusion integrates information from multiple sensors.
One way to achieve autonomous control employs multiple control-loop layers, as in hierarchical control systems. As of 2016 the low-layer loops (i.e. for flight control) tick as fast as 32,000 times per second, while higher-level loops may cycle once per second. The principle is to decompose the aircraft's behavior into manageable "chunks", or states, with known transitions. Hierarchical control system types range from simple scripts to finite state machines, behavior trees and hierarchical task planners. The most common control mechanism used in these layers is the PID controller which can be used to achieve hover for a quadcopter by using data from the IMUto calculate precise inputs for the electronic speed controllers and motors.
Examples of mid-layer algorithms:
Path planning: determining an optimal path for vehicle to follow while meeting mission objectives and constraints, such as obstacles or fuel requirements
Trajectory generation (motion planning): determining control maneuvers to take in order to follow a given path or to go from one location to another
Trajectory regulation: constraining a vehicle within some tolerance to a trajectory
Full autonomy is available for specific tasks, such as airborne refueling or ground-based battery switching; but higher-level tasks call for greater computing, sensing and actuating capabilities. One approach to quantifying autonomous capabilities is based on OODA terminology, as suggested by a 2002 US Air Force Research Laboratory, and used in the table below:
Most range sensors analyze electromagnetic radiation, reflected off the environment and coming to the sensor. The cameras (for visual flow) act as simple receivers. Lidars, radars and sonars (with sound mechanical waves) emit and receive waves, measuring the round-trip transit time. UAV cameras do not require emitting power, reducing total consumption.
Radars and sonars are mostly used for military applications.
Reactive autonomy has in some forms already reached consumer markets: it may be widely available in less than a decade.
Cutting-edge (2013) autonomous levels for existing systems
SLAM combines odometry and external data to represent the world and the position of the UAV in it in three dimensions. High-altitude outdoor navigation does not require large vertical fields-of-view and can rely on GPS coordinates (which makes it simple mapping rather than SLAM).
Two related research fields are photogrammetry and LIDAR, especially in low-altitude and indoor 3D environments.
Robot swarming refers to networks of agents able to dynamically reconfigure as elements leave or enter the network. They provide greater flexibility than multi-agent cooperation. Swarming may open the path to data fusion. Some bio-inspired flight swarms use steering behaviors and flocking.[clarification needed]
In the military sector, American Predators and Reapers are made for counterterrorism operations and in war zones in which the enemy lacks sufficient firepower to shoot them down. They are not designed to withstand antiaircraft defenses or air-to-air combat. In September 2013, the chief of the US Air Combat Command stated that current UAVs were "useless in a contested environment" unless manned aircraft were there to protect them. A 2012 Congressional Research Service (CRS) report speculated that in the future, UAVs may be able to perform tasks beyond intelligence, surveillance, reconnaissance and strikes; the CRS report listed air-to-air combat ("a more difficult future task") as possible future undertakings. The Department of Defense's Unmanned Systems Integrated Roadmap FY2013-2038 foresees a more important place for UAVs in combat. Issues include extended capabilities, human-UAV interaction, managing increased information flux, increased autonomy and developing UAV-specific munitions. DARPA's project of systems of systems, or General Atomicswork may augur future warfare scenarios, the latter disclosing Avenger swarms equipped with High Energy Liquid Laser Area Defense System (HELLADS).
The global military UAV market is dominated by United States and Israel companies. By sale numbers, The US held over 60% military-market share in 2017. Four of top five military UAV manufactures are American including General Atomics, Lockheed Martin, Northrop Grumman and Boeing, followed by the Chinese company CASC. Israel companies mainly focus on small surveillance UAV system and by quantity of drones, Israel exported 60.7% (2014) of UAV on the market while the United States export 23.9% (2014); top importers of military UAV are The United Kingdom (33.9%) and India (13.2%). United States alone operated over 9,000 military UAVs in 2014. General Atomics is the dominant manufacturer with the Global Hawk and Predator/Mariner systems product-line.
The civilian drone market is dominated by Chinese companies. Chinese drone manufacturer DJI alone has 75% of civilian-market share in 2017 with $11 billion forecast global sales in 2020. Followed by French company Parrot with $110m and US company 3DRobotics with $21.6m in 2014. As of March 2017, more than 770,000 civilian UAVs were registered with the U.S. FAA, though it is estimated more than 1.1 million have been sold in the United States alone.
Civilian UAV market is relatively new compare to military. Companies are emerging in both developed and developing nations at the same time. Many early stage startups have received support and funding from investors like in United States and by government agencies as the case in India. Some universities offer research and training programs or degrees. Private entities also provide online and in-person training programs for both recreational and commercial UAV use.
Consumer drones are also widely used by military organizations worldwide because of the cost-effective nature of consumer product. In 2018, Israeli military started to use DJIMavic and Matrice series of UAV for light reconnaissance mission since the civilian drones is easier to use and has higher reliability. DJI drones is also the most widely used commercial unmanned aerial system that the US Army has employed.
The AIA reports large cargo and passengers drones should be certified and introduced over the next 20 years. Sensor-carrying large drones are expected from 2018; short-haul, low altitude freighters outside cities from 2025; long-haul cargo flights by the mid-2030s and then passenger flights by 2040. Spending should rise from a few hundred million dollars on research and development in 2018 to $4 billion by 2028 and $30 billion by 2036.
Flapping-wing ornithopters, imitating birds or insects, are a research field in microUAVs. Their inherent stealth recommends them for spy missions.
The Nano Hummingbird is commercially available, while sub-1g microUAVs inspired by flies, albeit using a power tether, can "land" on vertical surfaces.
Other projects include unmanned "beetles" and other insects.
Research is exploring miniature optic-flow sensors, called ocellis, mimicking the compound insect eyes formed from multiple facets, which can transmit data to neuromorphic chips able to treat optic flow as well as light intensity discrepancies.
Flight time against mass of small (less than 1 kg) drones.
UAV endurance is not constrained by the physiological capabilities of a human pilot.
Because of their small size, low weight, low vibration and high power to weight ratio, Wankel rotary engines are used in many large UAVs. Their engine rotors cannot seize; the engine is not susceptible to shock-cooling during descent and it does not require an enriched fuel mixture for cooling at high power. These attributes reduce fuel usage, increasing range or payload.
Micro air vehicles endurance is so far best achieved with flapping-wing UAVs, followed by planes and multirotors standing last, due to lower Reynolds number.
Solar-electric UAVs, a concept originally championed by the AstroFlight Sunrise in 1974, have achieved flight times of several weeks.
Solar-powered atmospheric satellites ("atmosats") designed for operating at altitudes exceeding 20 km (12 miles, or 60,000 feet) for as long as five years could potentially perform duties more economically and with more versatility than low earth orbit satellites. Likely applications include weather monitoring, disaster recovery, earth imaging and communications.
Electric UAVs powered by microwave power transmission or laser power beaming are other potential endurance solutions.
Another application for a high endurance UAV would be to "stare" at a battlefield for a long interval (ARGUS-IS, Gorgon Stare, Integrated Sensor Is Structure) to record events that could then be played backwards to track battlefield activities.
Individual reliability covers robustness of flight controllers, to ensure safety without excessive redundancy to minimize cost and weight. Besides, dynamic assessment of flight envelopeallows damage-resilient UAVs, using non-linear analysis with ad-hoc designed loops or neural networks. UAV software liability is bending toward the design and certifications of manned avionics software.
Swarm resilience involves maintaining operational capabilities and reconfiguring tasks given unita failures.
UAVs can threaten airspace security in numerous ways, including unintentional collisions or other interference with other aircraft, deliberate attacks or by distracting pilots or flight controllers. The first incident of a drone-airplane collision occurred in mid-October 2017 in Quebec City, Canada.
UAVs could be loaded with dangerous payloads, and crashed into vulnerable targets. Payloads could include explosives, chemical, radiologial or biological hazards. UAVs with generally non-lethal payloads could possibly be hacked and put to malicious purposes. Anti-UAV systems are being developed by states to counter this threat. This is, however, proving difficult. As Dr J. Rogers stated in an interview to A&T "There is a big debate out there at the moment about what the best way is to counter these small UAVs, whether they are used by hobbyists causing a bit of a nuisance or in a more sinister manner by a terrorist actor.”
By 2017, drones were being used to drop contraband into prisons.
The interest in UAVs cyber security has been raised greatly after the Predator UAV video stream hijacking incident in 2009, where Islamic militants used cheap, off-the-shelf equipment to stream video feeds from a UAV. Another risk is the possibility of hijacking or jamming a UAV in flight. In recent years several security researchers have made public vulnerabilities for commercial UAVs, in some cases even providing full source code or tools to reproduce their attacks. At a workshop on UAVs and privacy in October 2016, researchers from the Federal Trade Commission showed they were able to hack into three different consumer quadcopters and noted that UAV manufacturers can make their UAVs more secure by the basic security measures of encrypting the Wi-Fi signal and adding password protection.
In the United States, flying close to a wildfire is punishable by a maximum $25,000 fine. Nonetheless, in 2014 and 2015, firefighting air support in California was hindered on several occasions, including at the Lake Fire and the North Fire. In response, California legislators introduced a bill that would allow firefighters to disable UAVs which invaded restricted airspace. The FAA later required registration of most UAVs.
The use of UAVs is also being investigated to help detect and fight wildfires, whether through observation or launching pyrotechnic devices to start backfires.
In April 2014, the South African Civil Aviation Authority announced that it would clamp down on the illegal flying of UAVs in South African airspace. "Hobby drones" with a weight of less than 7 kg at altitudes up to 500m with restricted visual line-of-sight below the height of the highest obstacle within 300m of the UAV are allowed. No license is required for such vehicles.
The ENAC (Ente Nazionale per l'Aviazione Civile), that is, the Italian Civil Aviation Authority for technical regulation, certification, supervision and control in the field of civil aviation, issued on May 31, 2016 a very detailed regulation for all UAV, determining which types of vehicles can be used, where, for which purposes, and who can control them. The regulation deals with the usage of UAV for either commercial and recreational use. Last version was published on December 22, 2016.
From 21 December 2015 all hobby type UAV's between 250 grams and 25 kilograms needed to be registered with FAA no later than 19 February 2016.
The new FAA UAV registration process includes requirements for:
Eligible owners must register their UAV's prior to flight.
If the owner is less than 13 years old, a parent or other responsible person must do the FAA registration.
UAV's must be marked with the FAA-issued registration number.
The registration fee is $5. The registration is good for 3 years and can be renewed for an additional 3 years at the $5 rate.
A single registration applies to all UAVs owned by an individual. Failure to register can result in civil penalties of up to $27,500 and criminal penalties of up to $250,000 and/or imprisonment for up to three years.
On 21 June 2016 the Federal Aviation Administration announced regulations for commercial operation of small UAS craft (sUAS), those between 0.55 and 55 pounds (about 250 gm to 25 kg) including payload. The rules, which exclude hobbyists, require the presence at all operations of a licensed Remote Pilot in Command. Certification of this position, available to any citizen at least 16 years of age, is obtained solely by passing a written test and then submitting an application. For those holding a sport pilot license or higher, and with a current flight review, a rule-specific exam can be taken at no charge online at the faasafety.gov website. Other applicants must take a more comprehensive examination at an aeronautical testing center. All licensees are required to take a review course every two years. At this time no ratings for heavier UAS are available.
Commercial operation is restricted to daylight, line-of-sight, under 100 mph, under 400 feet, and Class G airspace only, and may not fly over people or be operated from a moving vehicle. Some organizations have obtained a waiver or Certificate of Authorization that allows them to exceed these rules. For example, CNN has obtained a waiver for UAVs modified for injury prevention to fly over people, and other waivers allow night flying with special lighting, or non-line-of-sight operations for agriculture or railroad track inspection.
Previous to this announcement, any commercial use required a full pilot's license and an FAA waiver, of which hundreds had been granted.
As of December 20, 2017, UAV's of 250g or less are not controlled by the CAA guidances that include maintaining 50 meters from person, animal or property.
The UAV must still not go higher than 400 ft with a single pilot or 1000 ft with a pilot and spotter, however as with UAV's above 300g, if within 400 ft of a structure, you are allowed to go 400 ft higher than the structure.
Jump up^The Encyclopedia of the Arab-Israeli Conflict: A Political, Social, and Military History: A Political, Social, and Military History, ABC-CLIO, 12 May 2008, by Spencer C. Tucker, Priscilla Mary Roberts, page 1054-55 ISBN
Jump up^Z. Goraj; A. Frydrychewicz; R. Świtkiewicz; B. Hernik; J. Gadomski; T. Goetzendorf-Grabowski; M. Figat; St Suchodolski; W. Chajec. report(PDF). Bulletin of the Polish Academy of Sciences, Technical Sciences, Volume 52. Number 3, 2004. Retrieved 9 December 2015.
UVS International Non Profit Organization representing manufacturers of unmanned vehicle systems (UVS), subsystems and critical components for UVS and associated equipment, as well as companies supplying services with or for UVS, research organizations and academia.
Cities and Drones National League of Cities report on urban government use and regulation of UAS equipment
Drones and Drone Data Technical Interest Group (TIG) Technology and techniques (equipment, software, workflows, survey designs) to allow individuals to enhance their capabilities with data obtained from drones and drone surveys. Chaired by Karl Osvald and James McDonald.